Fixed MTP to work with TWRP

fs/ext4/Kconfig

@@ -0,0 +1,75 @@
+config EXT4_FS
+	tristate "The Extended 4 (ext4) filesystem"
+	select JBD2
+	select CRC16
+	select CRYPTO
+	select CRYPTO_CRC32C
+	help
+	  This is the next generation of the ext3 filesystem.
+
+	  Unlike the change from ext2 filesystem to ext3 filesystem,
+	  the on-disk format of ext4 is not forwards compatible with
+	  ext3; it is based on extent maps and it supports 48-bit
+	  physical block numbers.  The ext4 filesystem also supports delayed
+	  allocation, persistent preallocation, high resolution time stamps,
+	  and a number of other features to improve performance and speed
+	  up fsck time.  For more information, please see the web pages at
+	  http://ext4.wiki.kernel.org.
+
+	  The ext4 filesystem will support mounting an ext3
+	  filesystem; while there will be some performance gains from
+	  the delayed allocation and inode table readahead, the best
+	  performance gains will require enabling ext4 features in the
+	  filesystem, or formatting a new filesystem as an ext4
+	  filesystem initially.
+
+	  To compile this file system support as a module, choose M here. The
+	  module will be called ext4.
+
+	  If unsure, say N.
+
+config EXT4_USE_FOR_EXT23
+	bool "Use ext4 for ext2/ext3 file systems"
+	depends on EXT4_FS
+	depends on EXT3_FS=n || EXT2_FS=n
+	default y
+	help
+	  Allow the ext4 file system driver code to be used for ext2 or
+	  ext3 file system mounts.  This allows users to reduce their
+	  compiled kernel size by using one file system driver for
+	  ext2, ext3, and ext4 file systems.
+
+config EXT4_FS_POSIX_ACL
+	bool "Ext4 POSIX Access Control Lists"
+	depends on EXT4_FS
+	select FS_POSIX_ACL
+	help
+	  POSIX Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  To learn more about Access Control Lists, visit the POSIX ACLs for
+	  Linux website <http://acl.bestbits.at/>.
+
+	  If you don't know what Access Control Lists are, say N
+
+config EXT4_FS_SECURITY
+	bool "Ext4 Security Labels"
+	depends on EXT4_FS
+	help
+	  Security labels support alternative access control models
+	  implemented by security modules like SELinux.  This option
+	  enables an extended attribute handler for file security
+	  labels in the ext4 filesystem.
+
+	  If you are not using a security module that requires using
+	  extended attributes for file security labels, say N.
+
+config EXT4_DEBUG
+	bool "EXT4 debugging support"
+	depends on EXT4_FS
+	help
+	  Enables run-time debugging support for the ext4 filesystem.
+
+	  If you select Y here, then you will be able to turn on debugging
+	  with a command such as:
+		echo 1 > /sys/module/ext4/parameters/mballoc_debug

fs/ext4/Makefile

@@ -0,0 +1,18 @@
+#
+# Makefile for the linux ext4-filesystem routines.
+#
+
+ifeq ($(SEC_BUILD_CONF_QUICK_DMVERITY),true)
+EXTRA_CFLAGS += -DVERIFY_META_ONLY=true
+endif
+
+obj-$(CONFIG_EXT4_FS) += ext4.o
+
+ext4-y	:= balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
+		ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o \
+		ext4_jbd2.o migrate.o mballoc.o block_validity.o move_extent.o \
+		mmp.o indirect.o extents_status.o xattr.o xattr_user.o \
+		xattr_trusted.o inline.o
+
+ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
+ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o

fs/ext4/acl.c

@@ -0,0 +1,288 @@
+/*
+ * linux/fs/ext4/acl.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * Convert from filesystem to in-memory representation.
+ */
+static struct posix_acl *
+ext4_acl_from_disk(const void *value, size_t size)
+{
+	const char *end = (char *)value + size;
+	int n, count;
+	struct posix_acl *acl;
+
+	if (!value)
+		return NULL;
+	if (size < sizeof(ext4_acl_header))
+		 return ERR_PTR(-EINVAL);
+	if (((ext4_acl_header *)value)->a_version !=
+	    cpu_to_le32(EXT4_ACL_VERSION))
+		return ERR_PTR(-EINVAL);
+	value = (char *)value + sizeof(ext4_acl_header);
+	count = ext4_acl_count(size);
+	if (count < 0)
+		return ERR_PTR(-EINVAL);
+	if (count == 0)
+		return NULL;
+	acl = posix_acl_alloc(count, GFP_NOFS);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+	for (n = 0; n < count; n++) {
+		ext4_acl_entry *entry =
+			(ext4_acl_entry *)value;
+		if ((char *)value + sizeof(ext4_acl_entry_short) > end)
+			goto fail;
+		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
+		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
+
+		switch (acl->a_entries[n].e_tag) {
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			value = (char *)value +
+				sizeof(ext4_acl_entry_short);
+			break;
+
+		case ACL_USER:
+			value = (char *)value + sizeof(ext4_acl_entry);
+			if ((char *)value > end)
+				goto fail;
+			acl->a_entries[n].e_uid =
+				make_kuid(&init_user_ns,
+					  le32_to_cpu(entry->e_id));
+			break;
+		case ACL_GROUP:
+			value = (char *)value + sizeof(ext4_acl_entry);
+			if ((char *)value > end)
+				goto fail;
+			acl->a_entries[n].e_gid =
+				make_kgid(&init_user_ns,
+					  le32_to_cpu(entry->e_id));
+			break;
+
+		default:
+			goto fail;
+		}
+	}
+	if (value != end)
+		goto fail;
+	return acl;
+
+fail:
+	posix_acl_release(acl);
+	return ERR_PTR(-EINVAL);
+}
+
+/*
+ * Convert from in-memory to filesystem representation.
+ */
+static void *
+ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
+{
+	ext4_acl_header *ext_acl;
+	char *e;
+	size_t n;
+
+	*size = ext4_acl_size(acl->a_count);
+	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
+			sizeof(ext4_acl_entry), GFP_NOFS);
+	if (!ext_acl)
+		return ERR_PTR(-ENOMEM);
+	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
+	e = (char *)ext_acl + sizeof(ext4_acl_header);
+	for (n = 0; n < acl->a_count; n++) {
+		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
+		ext4_acl_entry *entry = (ext4_acl_entry *)e;
+		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+		entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch (acl_e->e_tag) {
+		case ACL_USER:
+			entry->e_id = cpu_to_le32(
+				from_kuid(&init_user_ns, acl_e->e_uid));
+			e += sizeof(ext4_acl_entry);
+			break;
+		case ACL_GROUP:
+			entry->e_id = cpu_to_le32(
+				from_kgid(&init_user_ns, acl_e->e_gid));
+			e += sizeof(ext4_acl_entry);
+			break;
+
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			e += sizeof(ext4_acl_entry_short);
+			break;
+
+		default:
+			goto fail;
+		}
+	}
+	return (char *)ext_acl;
+
+fail:
+	kfree(ext_acl);
+	return ERR_PTR(-EINVAL);
+}
+
+/*
+ * Inode operation get_posix_acl().
+ *
+ * inode->i_mutex: don't care
+ */
+struct posix_acl *
+ext4_get_acl(struct inode *inode, int type)
+{
+	int name_index;
+	char *value = NULL;
+	struct posix_acl *acl;
+	int retval;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
+	if (retval > 0) {
+		value = kmalloc(retval, GFP_NOFS);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		retval = ext4_xattr_get(inode, name_index, "", value, retval);
+	}
+	if (retval > 0)
+		acl = ext4_acl_from_disk(value, retval);
+	else if (retval == -ENODATA || retval == -ENOSYS)
+		acl = NULL;
+	else
+		acl = ERR_PTR(retval);
+	kfree(value);
+
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
+
+	return acl;
+}
+
+/*
+ * Set the access or default ACL of an inode.
+ *
+ * inode->i_mutex: down unless called from ext4_new_inode
+ */
+static int
+__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
+	     struct posix_acl *acl)
+{
+	int name_index;
+	void *value = NULL;
+	size_t size = 0;
+	int error;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
+		if (acl) {
+			error = posix_acl_equiv_mode(acl, &inode->i_mode);
+			if (error < 0)
+				return error;
+			else {
+				inode->i_ctime = ext4_current_time(inode);
+				ext4_mark_inode_dirty(handle, inode);
+				if (error == 0)
+					acl = NULL;
+			}
+		}
+		break;
+
+	case ACL_TYPE_DEFAULT:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		if (!S_ISDIR(inode->i_mode))
+			return acl ? -EACCES : 0;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	if (acl) {
+		value = ext4_acl_to_disk(acl, &size);
+		if (IS_ERR(value))
+			return (int)PTR_ERR(value);
+	}
+
+	error = ext4_xattr_set_handle(handle, inode, name_index, "",
+				      value, size, 0);
+
+	kfree(value);
+	if (!error)
+		set_cached_acl(inode, type, acl);
+
+	return error;
+}
+
+int
+ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	handle_t *handle;
+	int error, retries = 0;
+
+retry:
+	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
+				    ext4_jbd2_credits_xattr(inode));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	error = __ext4_set_acl(handle, inode, type, acl);
+	ext4_journal_stop(handle);
+	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+	return error;
+}
+
+/*
+ * Initialize the ACLs of a new inode. Called from ext4_new_inode.
+ *
+ * dir->i_mutex: down
+ * inode->i_mutex: up (access to inode is still exclusive)
+ */
+int
+ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	struct posix_acl *default_acl, *acl;
+	int error;
+
+	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
+	if (error)
+		return error;
+
+	if (default_acl) {
+		error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
+				       default_acl);
+		posix_acl_release(default_acl);
+	}
+	if (acl) {
+		if (!error)
+			error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
+					       acl);
+		posix_acl_release(acl);
+	}
+	return error;
+}

fs/ext4/acl.h

@@ -0,0 +1,72 @@
+/*
+  File: fs/ext4/acl.h
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/posix_acl_xattr.h>
+
+#define EXT4_ACL_VERSION	0x0001
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+	__le32		e_id;
+} ext4_acl_entry;
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+} ext4_acl_entry_short;
+
+typedef struct {
+	__le32		a_version;
+} ext4_acl_header;
+
+static inline size_t ext4_acl_size(int count)
+{
+	if (count <= 4) {
+		return sizeof(ext4_acl_header) +
+		       count * sizeof(ext4_acl_entry_short);
+	} else {
+		return sizeof(ext4_acl_header) +
+		       4 * sizeof(ext4_acl_entry_short) +
+		       (count - 4) * sizeof(ext4_acl_entry);
+	}
+}
+
+static inline int ext4_acl_count(size_t size)
+{
+	ssize_t s;
+	size -= sizeof(ext4_acl_header);
+	s = size - 4 * sizeof(ext4_acl_entry_short);
+	if (s < 0) {
+		if (size % sizeof(ext4_acl_entry_short))
+			return -1;
+		return size / sizeof(ext4_acl_entry_short);
+	} else {
+		if (s % sizeof(ext4_acl_entry))
+			return -1;
+		return s / sizeof(ext4_acl_entry) + 4;
+	}
+}
+
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+
+/* acl.c */
+struct posix_acl *ext4_get_acl(struct inode *inode, int type);
+int ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+extern int ext4_init_acl(handle_t *, struct inode *, struct inode *);
+
+#else  /* CONFIG_EXT4_FS_POSIX_ACL */
+#include <linux/sched.h>
+#define ext4_get_acl NULL
+#define ext4_set_acl NULL
+
+static inline int
+ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	return 0;
+}
+#endif  /* CONFIG_EXT4_FS_POSIX_ACL */
+

fs/ext4/balloc.c

@@ -0,0 +1,883 @@
+/*
+ *  linux/fs/ext4/balloc.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/time.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "mballoc.h"
+
+#include <trace/events/ext4.h>
+
+static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
+					    ext4_group_t block_group);
+/*
+ * balloc.c contains the blocks allocation and deallocation routines
+ */
+
+/*
+ * Calculate block group number for a given block number
+ */
+ext4_group_t ext4_get_group_number(struct super_block *sb,
+				   ext4_fsblk_t block)
+{
+	ext4_group_t group;
+
+	if (test_opt2(sb, STD_GROUP_SIZE))
+		group = (block -
+			 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >>
+			(EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3);
+	else
+		ext4_get_group_no_and_offset(sb, block, &group, NULL);
+	return group;
+}
+
+/*
+ * Calculate the block group number and offset into the block/cluster
+ * allocation bitmap, given a block number
+ */
+void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
+		ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	ext4_grpblk_t offset;
+
+	blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
+	offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
+		EXT4_SB(sb)->s_cluster_bits;
+	if (offsetp)
+		*offsetp = offset;
+	if (blockgrpp)
+		*blockgrpp = blocknr;
+
+}
+
+/*
+ * Check whether the 'block' lives within the 'block_group'. Returns 1 if so
+ * and 0 otherwise.
+ */
+static inline int ext4_block_in_group(struct super_block *sb,
+				      ext4_fsblk_t block,
+				      ext4_group_t block_group)
+{
+	ext4_group_t actual_group;
+
+	actual_group = ext4_get_group_number(sb, block);
+	return (actual_group == block_group) ? 1 : 0;
+}
+
+/* Return the number of clusters used for file system metadata; this
+ * represents the overhead needed by the file system.
+ */
+static unsigned ext4_num_overhead_clusters(struct super_block *sb,
+					   ext4_group_t block_group,
+					   struct ext4_group_desc *gdp)
+{
+	unsigned num_clusters;
+	int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c;
+	ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group);
+	ext4_fsblk_t itbl_blk;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	/* This is the number of clusters used by the superblock,
+	 * block group descriptors, and reserved block group
+	 * descriptor blocks */
+	num_clusters = ext4_num_base_meta_clusters(sb, block_group);
+
+	/*
+	 * For the allocation bitmaps and inode table, we first need
+	 * to check to see if the block is in the block group.  If it
+	 * is, then check to see if the cluster is already accounted
+	 * for in the clusters used for the base metadata cluster, or
+	 * if we can increment the base metadata cluster to include
+	 * that block.  Otherwise, we will have to track the cluster
+	 * used for the allocation bitmap or inode table explicitly.
+	 * Normally all of these blocks are contiguous, so the special
+	 * case handling shouldn't be necessary except for *very*
+	 * unusual file system layouts.
+	 */
+	if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
+		block_cluster = EXT4_B2C(sbi,
+					 ext4_block_bitmap(sb, gdp) - start);
+		if (block_cluster < num_clusters)
+			block_cluster = -1;
+		else if (block_cluster == num_clusters) {
+			num_clusters++;
+			block_cluster = -1;
+		}
+	}
+
+	if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
+		inode_cluster = EXT4_B2C(sbi,
+					 ext4_inode_bitmap(sb, gdp) - start);
+		if (inode_cluster < num_clusters)
+			inode_cluster = -1;
+		else if (inode_cluster == num_clusters) {
+			num_clusters++;
+			inode_cluster = -1;
+		}
+	}
+
+	itbl_blk = ext4_inode_table(sb, gdp);
+	for (i = 0; i < sbi->s_itb_per_group; i++) {
+		if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
+			c = EXT4_B2C(sbi, itbl_blk + i - start);
+			if ((c < num_clusters) || (c == inode_cluster) ||
+			    (c == block_cluster) || (c == itbl_cluster))
+				continue;
+			if (c == num_clusters) {
+				num_clusters++;
+				continue;
+			}
+			num_clusters++;
+			itbl_cluster = c;
+		}
+	}
+
+	if (block_cluster != -1)
+		num_clusters++;
+	if (inode_cluster != -1)
+		num_clusters++;
+
+	return num_clusters;
+}
+
+static unsigned int num_clusters_in_group(struct super_block *sb,
+					  ext4_group_t block_group)
+{
+	unsigned int blocks;
+
+	if (block_group == ext4_get_groups_count(sb) - 1) {
+		/*
+		 * Even though mke2fs always initializes the first and
+		 * last group, just in case some other tool was used,
+		 * we need to make sure we calculate the right free
+		 * blocks.
+		 */
+		blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) -
+			ext4_group_first_block_no(sb, block_group);
+	} else
+		blocks = EXT4_BLOCKS_PER_GROUP(sb);
+	return EXT4_NUM_B2C(EXT4_SB(sb), blocks);
+}
+
+/* Initializes an uninitialized block bitmap */
+static int ext4_init_block_bitmap(struct super_block *sb,
+				   struct buffer_head *bh,
+				   ext4_group_t block_group,
+				   struct ext4_group_desc *gdp)
+{
+	unsigned int bit, bit_max;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_fsblk_t start, tmp;
+	int flex_bg = 0;
+	struct ext4_group_info *grp;
+
+	J_ASSERT_BH(bh, buffer_locked(bh));
+
+	/* If checksum is bad mark all blocks used to prevent allocation
+	 * essentially implementing a per-group read-only flag. */
+	if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
+		grp = ext4_get_group_info(sb, block_group);
+		if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
+			percpu_counter_sub(&sbi->s_freeclusters_counter,
+					   grp->bb_free);
+		set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
+		if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
+			int count;
+			count = ext4_free_inodes_count(sb, gdp);
+			percpu_counter_sub(&sbi->s_freeinodes_counter,
+					   count);
+		}
+		set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
+		return -EIO;
+	}
+	memset(bh->b_data, 0, sb->s_blocksize);
+
+	bit_max = ext4_num_base_meta_clusters(sb, block_group);
+	for (bit = 0; bit < bit_max; bit++)
+		ext4_set_bit(bit, bh->b_data);
+
+	start = ext4_group_first_block_no(sb, block_group);
+
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
+		flex_bg = 1;
+
+	/* Set bits for block and inode bitmaps, and inode table */
+	tmp = ext4_block_bitmap(sb, gdp);
+	if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
+		ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
+
+	tmp = ext4_inode_bitmap(sb, gdp);
+	if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
+		ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
+
+	tmp = ext4_inode_table(sb, gdp);
+	for (; tmp < ext4_inode_table(sb, gdp) +
+		     sbi->s_itb_per_group; tmp++) {
+		if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
+			ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
+	}
+
+	/*
+	 * Also if the number of blocks within the group is less than
+	 * the blocksize * 8 ( which is the size of bitmap ), set rest
+	 * of the block bitmap to 1
+	 */
+	ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
+			     sb->s_blocksize * 8, bh->b_data);
+	ext4_block_bitmap_csum_set(sb, block_group, gdp, bh);
+	ext4_group_desc_csum_set(sb, block_group, gdp);
+	return 0;
+}
+
+/* Return the number of free blocks in a block group.  It is used when
+ * the block bitmap is uninitialized, so we can't just count the bits
+ * in the bitmap. */
+unsigned ext4_free_clusters_after_init(struct super_block *sb,
+				       ext4_group_t block_group,
+				       struct ext4_group_desc *gdp)
+{
+	return num_clusters_in_group(sb, block_group) - 
+		ext4_num_overhead_clusters(sb, block_group, gdp);
+}
+
+/*
+ * The free blocks are managed by bitmaps.  A file system contains several
+ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
+ * block for inodes, N blocks for the inode table and data blocks.
+ *
+ * The file system contains group descriptors which are located after the
+ * super block.  Each descriptor contains the number of the bitmap block and
+ * the free blocks count in the block.  The descriptors are loaded in memory
+ * when a file system is mounted (see ext4_fill_super).
+ */
+
+/**
+ * ext4_get_group_desc() -- load group descriptor from disk
+ * @sb:			super block
+ * @block_group:	given block group
+ * @bh:			pointer to the buffer head to store the block
+ *			group descriptor
+ */
+struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
+					     ext4_group_t block_group,
+					     struct buffer_head **bh)
+{
+	unsigned int group_desc;
+	unsigned int offset;
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	struct ext4_group_desc *desc;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (block_group >= ngroups) {
+		ext4_error(sb, "block_group >= groups_count - block_group = %u,"
+			   " groups_count = %u", block_group, ngroups);
+
+		return NULL;
+	}
+
+	group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
+	offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
+	if (!sbi->s_group_desc[group_desc]) {
+		ext4_error(sb, "Group descriptor not loaded - "
+			   "block_group = %u, group_desc = %u, desc = %u",
+			   block_group, group_desc, offset);
+		return NULL;
+	}
+
+	desc = (struct ext4_group_desc *)(
+		(__u8 *)sbi->s_group_desc[group_desc]->b_data +
+		offset * EXT4_DESC_SIZE(sb));
+	if (bh)
+		*bh = sbi->s_group_desc[group_desc];
+	return desc;
+}
+
+/*
+ * Return the block number which was discovered to be invalid, or 0 if
+ * the block bitmap is valid.
+ */
+static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
+					    struct ext4_group_desc *desc,
+					    ext4_group_t block_group,
+					    struct buffer_head *bh)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_grpblk_t offset;
+	ext4_grpblk_t next_zero_bit;
+	ext4_fsblk_t blk;
+	ext4_fsblk_t group_first_block;
+
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
+		/* with FLEX_BG, the inode/block bitmaps and itable
+		 * blocks may not be in the group at all
+		 * so the bitmap validation will be skipped for those groups
+		 * or it has to also read the block group where the bitmaps
+		 * are located to verify they are set.
+		 */
+		return 0;
+	}
+	group_first_block = ext4_group_first_block_no(sb, block_group);
+
+	/* check whether block bitmap block number is set */
+	blk = ext4_block_bitmap(sb, desc);
+	offset = blk - group_first_block;
+	if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
+		/* bad block bitmap */
+		return blk;
+
+	/* check whether the inode bitmap block number is set */
+	blk = ext4_inode_bitmap(sb, desc);
+	offset = blk - group_first_block;
+	if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
+		/* bad block bitmap */
+		return blk;
+
+	/* check whether the inode table block number is set */
+	blk = ext4_inode_table(sb, desc);
+	offset = blk - group_first_block;
+	next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
+			EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group),
+			EXT4_B2C(sbi, offset));
+	if (next_zero_bit <
+	    EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group))
+		/* bad bitmap for inode tables */
+		return blk;
+	return 0;
+}
+
+static void ext4_validate_block_bitmap(struct super_block *sb,
+				       struct ext4_group_desc *desc,
+				       ext4_group_t block_group,
+				       struct buffer_head *bh)
+{
+	ext4_fsblk_t	blk;
+	struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (buffer_verified(bh))
+		return;
+
+	ext4_lock_group(sb, block_group);
+	blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
+	if (unlikely(blk != 0)) {
+		ext4_unlock_group(sb, block_group);
+		ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
+			   block_group, blk);
+		if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
+			percpu_counter_sub(&sbi->s_freeclusters_counter,
+					   grp->bb_free);
+		set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
+		return;
+	}
+	if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
+			desc, bh))) {
+		ext4_unlock_group(sb, block_group);
+		ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
+		if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
+			percpu_counter_sub(&sbi->s_freeclusters_counter,
+					   grp->bb_free);
+		set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
+		return;
+	}
+	set_buffer_verified(bh);
+	ext4_unlock_group(sb, block_group);
+}
+
+/**
+ * ext4_read_block_bitmap_nowait()
+ * @sb:			super block
+ * @block_group:	given block group
+ *
+ * Read the bitmap for a given block_group,and validate the
+ * bits for block/inode/inode tables are set in the bitmaps
+ *
+ * Return buffer_head on success or NULL in case of failure.
+ */
+struct buffer_head *
+ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
+{
+	struct ext4_group_desc *desc;
+	struct buffer_head *bh;
+	ext4_fsblk_t bitmap_blk;
+
+	desc = ext4_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		return NULL;
+	bitmap_blk = ext4_block_bitmap(sb, desc);
+	bh = sb_getblk(sb, bitmap_blk);
+	if (unlikely(!bh)) {
+		ext4_error(sb, "Cannot get buffer for block bitmap - "
+			   "block_group = %u, block_bitmap = %llu",
+			   block_group, bitmap_blk);
+		return NULL;
+	}
+
+	if (bitmap_uptodate(bh))
+		goto verify;
+
+	lock_buffer(bh);
+	if (bitmap_uptodate(bh)) {
+		unlock_buffer(bh);
+		goto verify;
+	}
+	ext4_lock_group(sb, block_group);
+	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+		int err;
+
+		err = ext4_init_block_bitmap(sb, bh, block_group, desc);
+		set_bitmap_uptodate(bh);
+		set_buffer_uptodate(bh);
+		ext4_unlock_group(sb, block_group);
+		unlock_buffer(bh);
+		if (err)
+			ext4_error(sb, "Checksum bad for grp %u", block_group);
+		return bh;
+	}
+	ext4_unlock_group(sb, block_group);
+	if (buffer_uptodate(bh)) {
+		/*
+		 * if not uninit if bh is uptodate,
+		 * bitmap is also uptodate
+		 */
+		set_bitmap_uptodate(bh);
+		unlock_buffer(bh);
+		goto verify;
+	}
+	/*
+	 * submit the buffer_head for reading
+	 */
+	set_buffer_new(bh);
+	trace_ext4_read_block_bitmap_load(sb, block_group);
+	bh->b_end_io = ext4_end_bitmap_read;
+	get_bh(bh);
+	submit_bh(READ | REQ_META | REQ_PRIO, bh);
+	return bh;
+verify:
+	ext4_validate_block_bitmap(sb, desc, block_group, bh);
+	if (buffer_verified(bh))
+		return bh;
+	put_bh(bh);
+	return NULL;
+}
+
+/* Returns 0 on success, 1 on error */
+int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
+			   struct buffer_head *bh)
+{
+	struct ext4_group_desc *desc;
+
+	if (!buffer_new(bh))
+		return 0;
+	desc = ext4_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		return 1;
+	wait_on_buffer(bh);
+	if (!buffer_uptodate(bh)) {
+		ext4_error(sb, "Cannot read block bitmap - "
+			   "block_group = %u, block_bitmap = %llu",
+			   block_group, (unsigned long long) bh->b_blocknr);
+		return 1;
+	}
+	clear_buffer_new(bh);
+	/* Panic or remount fs read-only if block bitmap is invalid */
+	ext4_validate_block_bitmap(sb, desc, block_group, bh);
+	/* ...but check for error just in case errors=continue. */
+	return !buffer_verified(bh);
+}
+
+struct buffer_head *
+ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
+{
+	struct buffer_head *bh;
+
+	bh = ext4_read_block_bitmap_nowait(sb, block_group);
+	if (!bh)
+		return NULL;
+	if (ext4_wait_block_bitmap(sb, block_group, bh)) {
+		put_bh(bh);
+		return NULL;
+	}
+	return bh;
+}
+
+/**
+ * ext4_has_free_clusters()
+ * @sbi:	in-core super block structure.
+ * @nclusters:	number of needed blocks
+ * @flags:	flags from ext4_mb_new_blocks()
+ *
+ * Check if filesystem has nclusters free & available for allocation.
+ * On success return 1, return 0 on failure.
+ */
+static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
+				  s64 nclusters, unsigned int flags)
+{
+	s64 free_clusters, dirty_clusters, rsv, resv_clusters;
+	struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
+	struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
+
+	free_clusters  = percpu_counter_read_positive(fcc);
+	dirty_clusters = percpu_counter_read_positive(dcc);
+	resv_clusters = atomic64_read(&sbi->s_resv_clusters);
+
+	/*
+	 * r_blocks_count should always be multiple of the cluster ratio so
+	 * we are safe to do a plane bit shift only.
+	 */
+	rsv = (atomic64_read(&sbi->s_r_blocks_count) >> sbi->s_cluster_bits) +
+	      resv_clusters;
+
+	if (free_clusters - (nclusters + rsv + dirty_clusters) <
+					EXT4_FREECLUSTERS_WATERMARK) {
+		free_clusters  = percpu_counter_sum_positive(fcc);
+		dirty_clusters = percpu_counter_sum_positive(dcc);
+	}
+	/* Check whether we have space after accounting for current
+	 * dirty clusters & root reserved clusters.
+	 */
+	if (free_clusters >= (rsv + nclusters + dirty_clusters))
+		return 1;
+
+	/* Hm, nope.  Are (enough) root reserved clusters available? */
+	if (uid_eq(sbi->s_resuid, current_fsuid()) ||
+	    (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
+	    capable(CAP_SYS_RESOURCE) ||
+	    (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
+
+		if (free_clusters >= (nclusters + dirty_clusters +
+				      resv_clusters))
+			return 1;
+	}
+	/* No free blocks. Let's see if we can dip into reserved pool */
+	if (flags & EXT4_MB_USE_RESERVED) {
+		if (free_clusters >= (nclusters + dirty_clusters))
+			return 1;
+	}
+
+	return 0;
+}
+
+int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
+			     s64 nclusters, unsigned int flags)
+{
+	if (ext4_has_free_clusters(sbi, nclusters, flags)) {
+		percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
+		return 0;
+	} else
+		return -ENOSPC;
+}
+
+/**
+ * ext4_should_retry_alloc()
+ * @sb:			super block
+ * @retries		number of attemps has been made
+ *
+ * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
+ * it is profitable to retry the operation, this function will wait
+ * for the current or committing transaction to complete, and then
+ * return TRUE.
+ *
+ * if the total number of retries exceed three times, return FALSE.
+ */
+int ext4_should_retry_alloc(struct super_block *sb, int *retries)
+{
+	if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
+	    (*retries)++ > 3 ||
+	    !EXT4_SB(sb)->s_journal)
+		return 0;
+
+	jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
+
+	return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
+}
+
+/*
+ * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
+ *
+ * @handle:             handle to this transaction
+ * @inode:              file inode
+ * @goal:               given target block(filesystem wide)
+ * @count:		pointer to total number of clusters needed
+ * @errp:               error code
+ *
+ * Return 1st allocated block number on success, *count stores total account
+ * error stores in errp pointer
+ */
+ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
+				  ext4_fsblk_t goal, unsigned int flags,
+				  unsigned long *count, int *errp)
+{
+	struct ext4_allocation_request ar;
+	ext4_fsblk_t ret;
+
+	memset(&ar, 0, sizeof(ar));
+	/* Fill with neighbour allocated blocks */
+	ar.inode = inode;
+	ar.goal = goal;
+	ar.len = count ? *count : 1;
+	ar.flags = flags;
+
+	ret = ext4_mb_new_blocks(handle, &ar, errp);
+	if (count)
+		*count = ar.len;
+	/*
+	 * Account for the allocated meta blocks.  We will never
+	 * fail EDQUOT for metdata, but we do account for it.
+	 */
+	if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) {
+		spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+		dquot_alloc_block_nofail(inode,
+				EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
+	}
+	return ret;
+}
+
+/**
+ * ext4_count_free_clusters() -- count filesystem free clusters
+ * @sb:		superblock
+ *
+ * Adds up the number of free clusters from each block group.
+ */
+ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
+{
+	ext4_fsblk_t desc_count;
+	struct ext4_group_desc *gdp;
+	ext4_group_t i;
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	struct ext4_group_info *grp;
+#ifdef EXT4FS_DEBUG
+	struct ext4_super_block *es;
+	ext4_fsblk_t bitmap_count;
+	unsigned int x;
+	struct buffer_head *bitmap_bh = NULL;
+
+	es = EXT4_SB(sb)->s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		grp = NULL;
+		if (EXT4_SB(sb)->s_group_info)
+			grp = ext4_get_group_info(sb, i);
+		if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
+			desc_count += ext4_free_group_clusters(sb, gdp);
+		brelse(bitmap_bh);
+		bitmap_bh = ext4_read_block_bitmap(sb, i);
+		if (bitmap_bh == NULL)
+			continue;
+
+		x = ext4_count_free(bitmap_bh->b_data,
+				    EXT4_CLUSTERS_PER_GROUP(sb) / 8);
+		printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
+			i, ext4_free_group_clusters(sb, gdp), x);
+		bitmap_count += x;
+	}
+	brelse(bitmap_bh);
+	printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
+	       ", computed = %llu, %llu\n",
+	       EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
+	       desc_count, bitmap_count);
+	return bitmap_count;
+#else
+	desc_count = 0;
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		grp = NULL;
+		if (EXT4_SB(sb)->s_group_info)
+			grp = ext4_get_group_info(sb, i);
+		if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
+			desc_count += ext4_free_group_clusters(sb, gdp);
+	}
+
+	return desc_count;
+#endif
+}
+
+static inline int test_root(ext4_group_t a, int b)
+{
+	while (1) {
+		if (a < b)
+			return 0;
+		if (a == b)
+			return 1;
+		if ((a % b) != 0)
+			return 0;
+		a = a / b;
+	}
+}
+
+/**
+ *	ext4_bg_has_super - number of blocks used by the superblock in group
+ *	@sb: superblock for filesystem
+ *	@group: group number to check
+ *
+ *	Return the number of blocks used by the superblock (primary or backup)
+ *	in this group.  Currently this will be only 0 or 1.
+ */
+int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+	if (group == 0)
+		return 1;
+	if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_SPARSE_SUPER2)) {
+		if (group == le32_to_cpu(es->s_backup_bgs[0]) ||
+		    group == le32_to_cpu(es->s_backup_bgs[1]))
+			return 1;
+		return 0;
+	}
+	if ((group <= 1) || !EXT4_HAS_RO_COMPAT_FEATURE(sb,
+					EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
+		return 1;
+	if (!(group & 1))
+		return 0;
+	if (test_root(group, 3) || (test_root(group, 5)) ||
+	    test_root(group, 7))
+		return 1;
+
+	return 0;
+}
+
+static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
+					ext4_group_t group)
+{
+	unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
+	ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
+	ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
+
+	if (group == first || group == first + 1 || group == last)
+		return 1;
+	return 0;
+}
+
+static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
+					ext4_group_t group)
+{
+	if (!ext4_bg_has_super(sb, group))
+		return 0;
+
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG))
+		return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
+	else
+		return EXT4_SB(sb)->s_gdb_count;
+}
+
+/**
+ *	ext4_bg_num_gdb - number of blocks used by the group table in group
+ *	@sb: superblock for filesystem
+ *	@group: group number to check
+ *
+ *	Return the number of blocks used by the group descriptor table
+ *	(primary or backup) in this group.  In the future there may be a
+ *	different number of descriptor blocks in each group.
+ */
+unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
+{
+	unsigned long first_meta_bg =
+			le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
+	unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
+
+	if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) ||
+			metagroup < first_meta_bg)
+		return ext4_bg_num_gdb_nometa(sb, group);
+
+	return ext4_bg_num_gdb_meta(sb,group);
+
+}
+
+/*
+ * This function returns the number of file system metadata clusters at
+ * the beginning of a block group, including the reserved gdt blocks.
+ */
+static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
+				     ext4_group_t block_group)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	unsigned num;
+
+	/* Check for superblock and gdt backups in this group */
+	num = ext4_bg_has_super(sb, block_group);
+
+	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
+	    block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
+			  sbi->s_desc_per_block) {
+		if (num) {
+			num += ext4_bg_num_gdb(sb, block_group);
+			num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
+		}
+	} else { /* For META_BG_BLOCK_GROUPS */
+		num += ext4_bg_num_gdb(sb, block_group);
+	}
+	return EXT4_NUM_B2C(sbi, num);
+}
+/**
+ *	ext4_inode_to_goal_block - return a hint for block allocation
+ *	@inode: inode for block allocation
+ *
+ *	Return the ideal location to start allocating blocks for a
+ *	newly created inode.
+ */
+ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	ext4_group_t block_group;
+	ext4_grpblk_t colour;
+	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
+	ext4_fsblk_t bg_start;
+	ext4_fsblk_t last_block;
+
+	block_group = ei->i_block_group;
+	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
+		/*
+		 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
+		 * block groups per flexgroup, reserve the first block
+		 * group for directories and special files.  Regular
+		 * files will start at the second block group.  This
+		 * tends to speed up directory access and improves
+		 * fsck times.
+		 */
+		block_group &= ~(flex_size-1);
+		if (S_ISREG(inode->i_mode))
+			block_group++;
+	}
+	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
+	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
+
+	/*
+	 * If we are doing delayed allocation, we don't need take
+	 * colour into account.
+	 */
+	if (test_opt(inode->i_sb, DELALLOC))
+		return bg_start;
+
+	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
+		colour = (current->pid % 16) *
+			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
+	else
+		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
+	return bg_start + colour;
+}
+

fs/ext4/bitmap.c

@@ -0,0 +1,98 @@
+/*
+ *  linux/fs/ext4/bitmap.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/jbd2.h>
+#include "ext4.h"
+
+unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
+{
+	return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
+}
+
+int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh, int sz)
+{
+	__u32 hi;
+	__u32 provided, calculated;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!ext4_has_metadata_csum(sb))
+		return 1;
+
+	provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
+	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
+		hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
+		provided |= (hi << 16);
+	} else
+		calculated &= 0xFFFF;
+
+	return provided == calculated;
+}
+
+void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh, int sz)
+{
+	__u32 csum;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!ext4_has_metadata_csum(sb))
+		return;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
+	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
+		gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
+}
+
+int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh)
+{
+	__u32 hi;
+	__u32 provided, calculated;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
+
+	if (!ext4_has_metadata_csum(sb))
+		return 1;
+
+	provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
+	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
+		hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
+		provided |= (hi << 16);
+	} else
+		calculated &= 0xFFFF;
+
+	if (provided == calculated)
+		return 1;
+
+	return 0;
+}
+
+void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh)
+{
+	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
+	__u32 csum;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!ext4_has_metadata_csum(sb))
+		return;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
+	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
+		gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
+}

fs/ext4/block_validity.c

@@ -0,0 +1,253 @@
+/*
+ *  linux/fs/ext4/block_validity.c
+ *
+ * Copyright (C) 2009
+ * Theodore Ts'o (tytso@mit.edu)
+ *
+ * Track which blocks in the filesystem are metadata blocks that
+ * should never be used as data blocks by files or directories.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include "ext4.h"
+
+struct ext4_system_zone {
+	struct rb_node	node;
+	ext4_fsblk_t	start_blk;
+	unsigned int	count;
+};
+
+static struct kmem_cache *ext4_system_zone_cachep;
+
+int __init ext4_init_system_zone(void)
+{
+	ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, 0);
+	if (ext4_system_zone_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+void ext4_exit_system_zone(void)
+{
+	kmem_cache_destroy(ext4_system_zone_cachep);
+}
+
+static inline int can_merge(struct ext4_system_zone *entry1,
+		     struct ext4_system_zone *entry2)
+{
+	if ((entry1->start_blk + entry1->count) == entry2->start_blk)
+		return 1;
+	return 0;
+}
+
+/*
+ * Mark a range of blocks as belonging to the "system zone" --- that
+ * is, filesystem metadata blocks which should never be used by
+ * inodes.
+ */
+static int add_system_zone(struct ext4_sb_info *sbi,
+			   ext4_fsblk_t start_blk,
+			   unsigned int count)
+{
+	struct ext4_system_zone *new_entry = NULL, *entry;
+	struct rb_node **n = &sbi->system_blks.rb_node, *node;
+	struct rb_node *parent = NULL, *new_node = NULL;
+
+	while (*n) {
+		parent = *n;
+		entry = rb_entry(parent, struct ext4_system_zone, node);
+		if (start_blk < entry->start_blk)
+			n = &(*n)->rb_left;
+		else if (start_blk >= (entry->start_blk + entry->count))
+			n = &(*n)->rb_right;
+		else {
+			if (start_blk + count > (entry->start_blk +
+						 entry->count))
+				entry->count = (start_blk + count -
+						entry->start_blk);
+			new_node = *n;
+			new_entry = rb_entry(new_node, struct ext4_system_zone,
+					     node);
+			break;
+		}
+	}
+
+	if (!new_entry) {
+		new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
+					     GFP_KERNEL);
+		if (!new_entry)
+			return -ENOMEM;
+		new_entry->start_blk = start_blk;
+		new_entry->count = count;
+		new_node = &new_entry->node;
+
+		rb_link_node(new_node, parent, n);
+		rb_insert_color(new_node, &sbi->system_blks);
+	}
+
+	/* Can we merge to the left? */
+	node = rb_prev(new_node);
+	if (node) {
+		entry = rb_entry(node, struct ext4_system_zone, node);
+		if (can_merge(entry, new_entry)) {
+			new_entry->start_blk = entry->start_blk;
+			new_entry->count += entry->count;
+			rb_erase(node, &sbi->system_blks);
+			kmem_cache_free(ext4_system_zone_cachep, entry);
+		}
+	}
+
+	/* Can we merge to the right? */
+	node = rb_next(new_node);
+	if (node) {
+		entry = rb_entry(node, struct ext4_system_zone, node);
+		if (can_merge(new_entry, entry)) {
+			new_entry->count += entry->count;
+			rb_erase(node, &sbi->system_blks);
+			kmem_cache_free(ext4_system_zone_cachep, entry);
+		}
+	}
+	return 0;
+}
+
+static void debug_print_tree(struct ext4_sb_info *sbi)
+{
+	struct rb_node *node;
+	struct ext4_system_zone *entry;
+	int first = 1;
+
+	printk(KERN_INFO "System zones: ");
+	node = rb_first(&sbi->system_blks);
+	while (node) {
+		entry = rb_entry(node, struct ext4_system_zone, node);
+		printk("%s%llu-%llu", first ? "" : ", ",
+		       entry->start_blk, entry->start_blk + entry->count - 1);
+		first = 0;
+		node = rb_next(node);
+	}
+	printk("\n");
+}
+
+#ifdef VERIFY_META_ONLY
+struct rb_root *ext4_system_zone_root(struct super_block *sb)
+{
+	return &EXT4_SB(sb)->system_blks;
+}
+#endif
+int ext4_setup_system_zone(struct super_block *sb)
+{
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_group_desc *gdp;
+	ext4_group_t i;
+	int flex_size = ext4_flex_bg_size(sbi);
+	int ret;
+
+	if (!test_opt(sb, BLOCK_VALIDITY)) {
+		if (EXT4_SB(sb)->system_blks.rb_node)
+			ext4_release_system_zone(sb);
+		return 0;
+	}
+	if (EXT4_SB(sb)->system_blks.rb_node)
+		return 0;
+
+	for (i=0; i < ngroups; i++) {
+		if (ext4_bg_has_super(sb, i) &&
+		    ((i < 5) || ((i % flex_size) == 0)))
+			add_system_zone(sbi, ext4_group_first_block_no(sb, i),
+					ext4_bg_num_gdb(sb, i) + 1);
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1);
+		if (ret)
+			return ret;
+		ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1);
+		if (ret)
+			return ret;
+		ret = add_system_zone(sbi, ext4_inode_table(sb, gdp),
+				sbi->s_itb_per_group);
+		if (ret)
+			return ret;
+	}
+
+	if (test_opt(sb, DEBUG))
+		debug_print_tree(EXT4_SB(sb));
+	return 0;
+}
+
+/* Called when the filesystem is unmounted */
+void ext4_release_system_zone(struct super_block *sb)
+{
+	struct ext4_system_zone	*entry, *n;
+
+	rbtree_postorder_for_each_entry_safe(entry, n,
+			&EXT4_SB(sb)->system_blks, node)
+		kmem_cache_free(ext4_system_zone_cachep, entry);
+
+	EXT4_SB(sb)->system_blks = RB_ROOT;
+}
+
+/*
+ * Returns 1 if the passed-in block region (start_blk,
+ * start_blk+count) is valid; 0 if some part of the block region
+ * overlaps with filesystem metadata blocks.
+ */
+int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
+			  unsigned int count)
+{
+#ifndef VERIFY_META_ONLY
+	struct ext4_system_zone *entry;
+	struct rb_node *n = sbi->system_blks.rb_node;
+#endif
+
+	if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
+	    (start_blk + count < start_blk) ||
+	    (start_blk + count > ext4_blocks_count(sbi->s_es))) {
+		sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
+		return 0;
+	}
+#ifndef VERIFY_META_ONLY
+	while (n) {
+		entry = rb_entry(n, struct ext4_system_zone, node);
+		if (start_blk + count - 1 < entry->start_blk)
+			n = n->rb_left;
+		else if (start_blk >= (entry->start_blk + entry->count))
+			n = n->rb_right;
+		else {
+			sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
+			return 0;
+		}
+	}
+#endif
+	return 1;
+}
+
+int ext4_check_blockref(const char *function, unsigned int line,
+			struct inode *inode, __le32 *p, unsigned int max)
+{
+	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
+	__le32 *bref = p;
+	unsigned int blk;
+
+	while (bref < p+max) {
+		blk = le32_to_cpu(*bref++);
+		if (blk &&
+		    unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
+						    blk, 1))) {
+			es->s_last_error_block = cpu_to_le64(blk);
+			ext4_error_inode(inode, function, line, blk,
+					 "invalid block");
+			return -EIO;
+		}
+	}
+	return 0;
+}
+

fs/ext4/dir.c

@@ -0,0 +1,611 @@
+/*
+ *  linux/fs/ext4/dir.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/dir.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 directory handling functions
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ * Hash Tree Directory indexing (c) 2001  Daniel Phillips
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/rbtree.h>
+#include "ext4.h"
+#include "xattr.h"
+
+static int ext4_dx_readdir(struct file *, struct dir_context *);
+
+/**
+ * Check if the given dir-inode refers to an htree-indexed directory
+ * (or a directory which could potentially get converted to use htree
+ * indexing).
+ *
+ * Return 1 if it is a dx dir, 0 if not
+ */
+static int is_dx_dir(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+
+	if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
+		     EXT4_FEATURE_COMPAT_DIR_INDEX) &&
+	    ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
+	     ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
+	     ext4_has_inline_data(inode)))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Return 0 if the directory entry is OK, and 1 if there is a problem
+ *
+ * Note: this is the opposite of what ext2 and ext3 historically returned...
+ *
+ * bh passed here can be an inode block or a dir data block, depending
+ * on the inode inline data flag.
+ */
+int __ext4_check_dir_entry(const char *function, unsigned int line,
+			   struct inode *dir, struct file *filp,
+			   struct ext4_dir_entry_2 *de,
+			   struct buffer_head *bh, char *buf, int size,
+			   unsigned int offset)
+{
+	const char *error_msg = NULL;
+	const int rlen = ext4_rec_len_from_disk(de->rec_len,
+						dir->i_sb->s_blocksize);
+
+	if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
+		error_msg = "rec_len is smaller than minimal";
+	else if (unlikely(rlen % 4 != 0))
+		error_msg = "rec_len % 4 != 0";
+	else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
+		error_msg = "rec_len is too small for name_len";
+	else if (unlikely(((char *) de - buf) + rlen > size))
+		error_msg = "directory entry across range";
+	else if (unlikely(le32_to_cpu(de->inode) >
+			le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
+		error_msg = "inode out of bounds";
+	else
+		return 0;
+
+	/* for debugging, sangwoo2.lee */
+	print_bh(dir->i_sb, bh, 0, EXT4_BLOCK_SIZE(dir->i_sb));
+	/* for debugging */
+
+	if (filp)
+		ext4_error_file(filp, function, line, bh->b_blocknr,
+				"bad entry in directory: %s - offset=%u(%u), "
+				"inode=%u, rec_len=%d, name_len=%d",
+				error_msg, (unsigned) (offset % size),
+				offset, le32_to_cpu(de->inode),
+				rlen, de->name_len);
+	else
+		ext4_error_inode(dir, function, line, bh->b_blocknr,
+				"bad entry in directory: %s - offset=%u(%u), "
+				"inode=%u, rec_len=%d, name_len=%d",
+				error_msg, (unsigned) (offset % size),
+				offset, le32_to_cpu(de->inode),
+				rlen, de->name_len);
+
+	return 1;
+}
+
+static int ext4_readdir(struct file *file, struct dir_context *ctx)
+{
+	unsigned int offset;
+	int i;
+	struct ext4_dir_entry_2 *de;
+	int err;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	int dir_has_error = 0;
+
+	if (is_dx_dir(inode)) {
+		err = ext4_dx_readdir(file, ctx);
+		if (err != ERR_BAD_DX_DIR) {
+			return err;
+		}
+		/*
+		 * We don't set the inode dirty flag since it's not
+		 * critical that it get flushed back to the disk.
+		 */
+		ext4_clear_inode_flag(file_inode(file),
+				      EXT4_INODE_INDEX);
+	}
+
+	if (ext4_has_inline_data(inode)) {
+		int has_inline_data = 1;
+		int ret = ext4_read_inline_dir(file, ctx,
+					   &has_inline_data);
+		if (has_inline_data)
+			return ret;
+	}
+
+	offset = ctx->pos & (sb->s_blocksize - 1);
+
+	while (ctx->pos < inode->i_size) {
+		struct ext4_map_blocks map;
+		struct buffer_head *bh = NULL;
+
+		map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
+		map.m_len = 1;
+		err = ext4_map_blocks(NULL, inode, &map, 0);
+		if (err > 0) {
+			pgoff_t index = map.m_pblk >>
+					(PAGE_CACHE_SHIFT - inode->i_blkbits);
+			if (!ra_has_index(&file->f_ra, index))
+				page_cache_sync_readahead(
+					sb->s_bdev->bd_inode->i_mapping,
+					&file->f_ra, file,
+					index, 1);
+			file->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
+			bh = ext4_bread(NULL, inode, map.m_lblk, 0);
+			if (IS_ERR(bh))
+				return PTR_ERR(bh);
+		}
+
+		if (!bh) {
+			if (!dir_has_error) {
+				EXT4_ERROR_FILE(file, 0,
+						"directory contains a "
+						"hole at offset %llu",
+					   (unsigned long long) ctx->pos);
+				dir_has_error = 1;
+			}
+			/* corrupt size?  Maybe no more blocks to read */
+			if (ctx->pos > inode->i_blocks << 9)
+				break;
+			ctx->pos += sb->s_blocksize - offset;
+			continue;
+		}
+
+		/* Check the checksum */
+		if (!buffer_verified(bh) &&
+		    !ext4_dirent_csum_verify(inode,
+				(struct ext4_dir_entry *)bh->b_data)) {
+			EXT4_ERROR_FILE(file, 0, "directory fails checksum "
+					"at offset %llu",
+					(unsigned long long)ctx->pos);
+			ctx->pos += sb->s_blocksize - offset;
+			brelse(bh);
+			continue;
+		}
+		set_buffer_verified(bh);
+
+		/* If the dir block has changed since the last call to
+		 * readdir(2), then we might be pointing to an invalid
+		 * dirent right now.  Scan from the start of the block
+		 * to make sure. */
+		if (file->f_version != inode->i_version) {
+			for (i = 0; i < sb->s_blocksize && i < offset; ) {
+				de = (struct ext4_dir_entry_2 *)
+					(bh->b_data + i);
+				/* It's too expensive to do a full
+				 * dirent test each time round this
+				 * loop, but we do have to test at
+				 * least that it is non-zero.  A
+				 * failure will be detected in the
+				 * dirent test below. */
+				if (ext4_rec_len_from_disk(de->rec_len,
+					sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
+					break;
+				i += ext4_rec_len_from_disk(de->rec_len,
+							    sb->s_blocksize);
+			}
+			offset = i;
+			ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
+				| offset;
+			file->f_version = inode->i_version;
+		}
+
+		while (ctx->pos < inode->i_size
+		       && offset < sb->s_blocksize) {
+			de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
+			if (ext4_check_dir_entry(inode, file, de, bh,
+						 bh->b_data, bh->b_size,
+						 offset)) {
+				/*
+				 * On error, skip to the next block
+				 */
+				ctx->pos = (ctx->pos |
+						(sb->s_blocksize - 1)) + 1;
+				break;
+			}
+			offset += ext4_rec_len_from_disk(de->rec_len,
+					sb->s_blocksize);
+			if (le32_to_cpu(de->inode)) {
+				if (!dir_emit(ctx, de->name,
+						de->name_len,
+						le32_to_cpu(de->inode),
+						get_dtype(sb, de->file_type))) {
+					brelse(bh);
+					return 0;
+				}
+			}
+			ctx->pos += ext4_rec_len_from_disk(de->rec_len,
+						sb->s_blocksize);
+		}
+		offset = 0;
+		brelse(bh);
+		if (ctx->pos < inode->i_size) {
+			if (!dir_relax(inode))
+				return 0;
+		}
+	}
+	return 0;
+}
+
+static inline int is_32bit_api(void)
+{
+#ifdef CONFIG_COMPAT
+	return is_compat_task();
+#else
+	return (BITS_PER_LONG == 32);
+#endif
+}
+
+/*
+ * These functions convert from the major/minor hash to an f_pos
+ * value for dx directories
+ *
+ * Upper layer (for example NFS) should specify FMODE_32BITHASH or
+ * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
+ * directly on both 32-bit and 64-bit nodes, under such case, neither
+ * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
+ */
+static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return major >> 1;
+	else
+		return ((__u64)(major >> 1) << 32) | (__u64)minor;
+}
+
+static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return (pos << 1) & 0xffffffff;
+	else
+		return ((pos >> 32) << 1) & 0xffffffff;
+}
+
+static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return 0;
+	else
+		return pos & 0xffffffff;
+}
+
+/*
+ * Return 32- or 64-bit end-of-file for dx directories
+ */
+static inline loff_t ext4_get_htree_eof(struct file *filp)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return EXT4_HTREE_EOF_32BIT;
+	else
+		return EXT4_HTREE_EOF_64BIT;
+}
+
+
+/*
+ * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
+ * directories, where the "offset" is in terms of the filename hash
+ * value instead of the byte offset.
+ *
+ * Because we may return a 64-bit hash that is well beyond offset limits,
+ * we need to pass the max hash as the maximum allowable offset in
+ * the htree directory case.
+ *
+ * For non-htree, ext4_llseek already chooses the proper max offset.
+ */
+static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	int dx_dir = is_dx_dir(inode);
+	loff_t htree_max = ext4_get_htree_eof(file);
+
+	if (likely(dx_dir))
+		return generic_file_llseek_size(file, offset, whence,
+						    htree_max, htree_max);
+	else
+		return ext4_llseek(file, offset, whence);
+}
+
+/*
+ * This structure holds the nodes of the red-black tree used to store
+ * the directory entry in hash order.
+ */
+struct fname {
+	__u32		hash;
+	__u32		minor_hash;
+	struct rb_node	rb_hash;
+	struct fname	*next;
+	__u32		inode;
+	__u8		name_len;
+	__u8		file_type;
+	char		name[0];
+};
+
+/*
+ * This functoin implements a non-recursive way of freeing all of the
+ * nodes in the red-black tree.
+ */
+static void free_rb_tree_fname(struct rb_root *root)
+{
+	struct fname *fname, *next;
+
+	rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
+		while (fname) {
+			struct fname *old = fname;
+			fname = fname->next;
+			kfree(old);
+		}
+
+	*root = RB_ROOT;
+}
+
+
+static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
+							   loff_t pos)
+{
+	struct dir_private_info *p;
+
+	p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
+	if (!p)
+		return NULL;
+	p->curr_hash = pos2maj_hash(filp, pos);
+	p->curr_minor_hash = pos2min_hash(filp, pos);
+	return p;
+}
+
+void ext4_htree_free_dir_info(struct dir_private_info *p)
+{
+	free_rb_tree_fname(&p->root);
+	kfree(p);
+}
+
+/*
+ * Given a directory entry, enter it into the fname rb tree.
+ */
+int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
+			     __u32 minor_hash,
+			     struct ext4_dir_entry_2 *dirent)
+{
+	struct rb_node **p, *parent = NULL;
+	struct fname *fname, *new_fn;
+	struct dir_private_info *info;
+	int len;
+
+	info = dir_file->private_data;
+	p = &info->root.rb_node;
+
+	/* Create and allocate the fname structure */
+	len = sizeof(struct fname) + dirent->name_len + 1;
+	new_fn = kzalloc(len, GFP_KERNEL);
+	if (!new_fn)
+		return -ENOMEM;
+	new_fn->hash = hash;
+	new_fn->minor_hash = minor_hash;
+	new_fn->inode = le32_to_cpu(dirent->inode);
+	new_fn->name_len = dirent->name_len;
+	new_fn->file_type = dirent->file_type;
+	memcpy(new_fn->name, dirent->name, dirent->name_len);
+	new_fn->name[dirent->name_len] = 0;
+
+	while (*p) {
+		parent = *p;
+		fname = rb_entry(parent, struct fname, rb_hash);
+
+		/*
+		 * If the hash and minor hash match up, then we put
+		 * them on a linked list.  This rarely happens...
+		 */
+		if ((new_fn->hash == fname->hash) &&
+		    (new_fn->minor_hash == fname->minor_hash)) {
+			new_fn->next = fname->next;
+			fname->next = new_fn;
+			return 0;
+		}
+
+		if (new_fn->hash < fname->hash)
+			p = &(*p)->rb_left;
+		else if (new_fn->hash > fname->hash)
+			p = &(*p)->rb_right;
+		else if (new_fn->minor_hash < fname->minor_hash)
+			p = &(*p)->rb_left;
+		else /* if (new_fn->minor_hash > fname->minor_hash) */
+			p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&new_fn->rb_hash, parent, p);
+	rb_insert_color(&new_fn->rb_hash, &info->root);
+	return 0;
+}
+
+
+
+/*
+ * This is a helper function for ext4_dx_readdir.  It calls filldir
+ * for all entres on the fname linked list.  (Normally there is only
+ * one entry on the linked list, unless there are 62 bit hash collisions.)
+ */
+static int call_filldir(struct file *file, struct dir_context *ctx,
+			struct fname *fname)
+{
+	struct dir_private_info *info = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+
+	if (!fname) {
+		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
+			 "called with null fname?!?", __func__, __LINE__,
+			 inode->i_ino, current->comm);
+		return 0;
+	}
+	ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
+	while (fname) {
+		if (!dir_emit(ctx, fname->name,
+				fname->name_len,
+				fname->inode,
+				get_dtype(sb, fname->file_type))) {
+			info->extra_fname = fname;
+			return 1;
+		}
+		fname = fname->next;
+	}
+	return 0;
+}
+
+static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct dir_private_info *info = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct fname *fname;
+	int	ret;
+
+	if (!info) {
+		info = ext4_htree_create_dir_info(file, ctx->pos);
+		if (!info)
+			return -ENOMEM;
+		file->private_data = info;
+	}
+
+	if (ctx->pos == ext4_get_htree_eof(file))
+		return 0;	/* EOF */
+
+	/* Some one has messed with f_pos; reset the world */
+	if (info->last_pos != ctx->pos) {
+		free_rb_tree_fname(&info->root);
+		info->curr_node = NULL;
+		info->extra_fname = NULL;
+		info->curr_hash = pos2maj_hash(file, ctx->pos);
+		info->curr_minor_hash = pos2min_hash(file, ctx->pos);
+	}
+
+	/*
+	 * If there are any leftover names on the hash collision
+	 * chain, return them first.
+	 */
+	if (info->extra_fname) {
+		if (call_filldir(file, ctx, info->extra_fname))
+			goto finished;
+		info->extra_fname = NULL;
+		goto next_node;
+	} else if (!info->curr_node)
+		info->curr_node = rb_first(&info->root);
+
+	while (1) {
+		/*
+		 * Fill the rbtree if we have no more entries,
+		 * or the inode has changed since we last read in the
+		 * cached entries.
+		 */
+		if ((!info->curr_node) ||
+		    (file->f_version != inode->i_version)) {
+			info->curr_node = NULL;
+			free_rb_tree_fname(&info->root);
+			file->f_version = inode->i_version;
+			ret = ext4_htree_fill_tree(file, info->curr_hash,
+						   info->curr_minor_hash,
+						   &info->next_hash);
+			if (ret < 0)
+				return ret;
+			if (ret == 0) {
+				ctx->pos = ext4_get_htree_eof(file);
+				break;
+			}
+			info->curr_node = rb_first(&info->root);
+		}
+
+		fname = rb_entry(info->curr_node, struct fname, rb_hash);
+		info->curr_hash = fname->hash;
+		info->curr_minor_hash = fname->minor_hash;
+		if (call_filldir(file, ctx, fname))
+			break;
+	next_node:
+		info->curr_node = rb_next(info->curr_node);
+		if (info->curr_node) {
+			fname = rb_entry(info->curr_node, struct fname,
+					 rb_hash);
+			info->curr_hash = fname->hash;
+			info->curr_minor_hash = fname->minor_hash;
+		} else {
+			if (info->next_hash == ~0) {
+				ctx->pos = ext4_get_htree_eof(file);
+				break;
+			}
+			info->curr_hash = info->next_hash;
+			info->curr_minor_hash = 0;
+		}
+	}
+finished:
+	info->last_pos = ctx->pos;
+	return 0;
+}
+
+static int ext4_release_dir(struct inode *inode, struct file *filp)
+{
+	if (filp->private_data)
+		ext4_htree_free_dir_info(filp->private_data);
+
+	return 0;
+}
+
+int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
+		      int buf_size)
+{
+	struct ext4_dir_entry_2 *de;
+	int nlen, rlen;
+	unsigned int offset = 0;
+	char *top;
+
+	de = (struct ext4_dir_entry_2 *)buf;
+	top = buf + buf_size;
+	while ((char *) de < top) {
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+					 buf, buf_size, offset))
+			return -EIO;
+		nlen = EXT4_DIR_REC_LEN(de->name_len);
+		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
+		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
+		offset += rlen;
+	}
+	if ((char *) de > top)
+		return -EIO;
+
+	return 0;
+}
+
+const struct file_operations ext4_dir_operations = {
+	.llseek		= ext4_dir_llseek,
+	.read		= generic_read_dir,
+	.iterate	= ext4_readdir,
+	.unlocked_ioctl = ext4_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext4_compat_ioctl,
+#endif
+	.fsync		= ext4_sync_file,
+	.release	= ext4_release_dir,
+};

fs/ext4/ext4_extents.h

@@ -0,0 +1,274 @@
+/*
+ * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
+ * Written by Alex Tomas <alex@clusterfs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public Licens
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
+ */
+
+#ifndef _EXT4_EXTENTS
+#define _EXT4_EXTENTS
+
+#include "ext4.h"
+
+/*
+ * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
+ * becomes very small, so index split, in-depth growing and
+ * other hard changes happen much more often.
+ * This is for debug purposes only.
+ */
+#define AGGRESSIVE_TEST_
+
+/*
+ * With EXTENTS_STATS defined, the number of blocks and extents
+ * are collected in the truncate path. They'll be shown at
+ * umount time.
+ */
+#define EXTENTS_STATS__
+
+/*
+ * If CHECK_BINSEARCH is defined, then the results of the binary search
+ * will also be checked by linear search.
+ */
+#define CHECK_BINSEARCH__
+
+/*
+ * If EXT_STATS is defined then stats numbers are collected.
+ * These number will be displayed at umount time.
+ */
+#define EXT_STATS_
+
+
+/*
+ * ext4_inode has i_block array (60 bytes total).
+ * The first 12 bytes store ext4_extent_header;
+ * the remainder stores an array of ext4_extent.
+ * For non-inode extent blocks, ext4_extent_tail
+ * follows the array.
+ */
+
+/*
+ * This is the extent tail on-disk structure.
+ * All other extent structures are 12 bytes long.  It turns out that
+ * block_size % 12 >= 4 for at least all powers of 2 greater than 512, which
+ * covers all valid ext4 block sizes.  Therefore, this tail structure can be
+ * crammed into the end of the block without having to rebalance the tree.
+ */
+struct ext4_extent_tail {
+	__le32	et_checksum;	/* crc32c(uuid+inum+extent_block) */
+};
+
+/*
+ * This is the extent on-disk structure.
+ * It's used at the bottom of the tree.
+ */
+struct ext4_extent {
+	__le32	ee_block;	/* first logical block extent covers */
+	__le16	ee_len;		/* number of blocks covered by extent */
+	__le16	ee_start_hi;	/* high 16 bits of physical block */
+	__le32	ee_start_lo;	/* low 32 bits of physical block */
+};
+
+/*
+ * This is index on-disk structure.
+ * It's used at all the levels except the bottom.
+ */
+struct ext4_extent_idx {
+	__le32	ei_block;	/* index covers logical blocks from 'block' */
+	__le32	ei_leaf_lo;	/* pointer to the physical block of the next *
+				 * level. leaf or next index could be there */
+	__le16	ei_leaf_hi;	/* high 16 bits of physical block */
+	__u16	ei_unused;
+};
+
+/*
+ * Each block (leaves and indexes), even inode-stored has header.
+ */
+struct ext4_extent_header {
+	__le16	eh_magic;	/* probably will support different formats */
+	__le16	eh_entries;	/* number of valid entries */
+	__le16	eh_max;		/* capacity of store in entries */
+	__le16	eh_depth;	/* has tree real underlying blocks? */
+	__le32	eh_generation;	/* generation of the tree */
+};
+
+#define EXT4_EXT_MAGIC		cpu_to_le16(0xf30a)
+
+#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
+	(sizeof(struct ext4_extent_header) + \
+	 (sizeof(struct ext4_extent) * le16_to_cpu((hdr)->eh_max)))
+
+static inline struct ext4_extent_tail *
+find_ext4_extent_tail(struct ext4_extent_header *eh)
+{
+	return (struct ext4_extent_tail *)(((void *)eh) +
+					   EXT4_EXTENT_TAIL_OFFSET(eh));
+}
+
+/*
+ * Array of ext4_ext_path contains path to some extent.
+ * Creation/lookup routines use it for traversal/splitting/etc.
+ * Truncate uses it to simulate recursive walking.
+ */
+struct ext4_ext_path {
+	ext4_fsblk_t			p_block;
+	__u16				p_depth;
+	__u16				p_maxdepth;
+	struct ext4_extent		*p_ext;
+	struct ext4_extent_idx		*p_idx;
+	struct ext4_extent_header	*p_hdr;
+	struct buffer_head		*p_bh;
+};
+
+/*
+ * structure for external API
+ */
+
+/*
+ * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
+ * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
+ * MSB of ee_len field in the extent datastructure to signify if this
+ * particular extent is an initialized extent or an unwritten (i.e.
+ * preallocated).
+ * EXT_UNWRITTEN_MAX_LEN is the maximum number of blocks we can have in an
+ * unwritten extent.
+ * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
+ * unwritten one. In other words, if MSB of ee_len is set, it is an
+ * unwritten extent with only one special scenario when ee_len = 0x8000.
+ * In this case we can not have an unwritten extent of zero length and
+ * thus we make it as a special case of initialized extent with 0x8000 length.
+ * This way we get better extent-to-group alignment for initialized extents.
+ * Hence, the maximum number of blocks we can have in an *initialized*
+ * extent is 2^15 (32768) and in an *unwritten* extent is 2^15-1 (32767).
+ */
+#define EXT_INIT_MAX_LEN	(1UL << 15)
+#define EXT_UNWRITTEN_MAX_LEN	(EXT_INIT_MAX_LEN - 1)
+
+
+#define EXT_FIRST_EXTENT(__hdr__) \
+	((struct ext4_extent *) (((char *) (__hdr__)) +		\
+				 sizeof(struct ext4_extent_header)))
+#define EXT_FIRST_INDEX(__hdr__) \
+	((struct ext4_extent_idx *) (((char *) (__hdr__)) +	\
+				     sizeof(struct ext4_extent_header)))
+#define EXT_HAS_FREE_INDEX(__path__) \
+	(le16_to_cpu((__path__)->p_hdr->eh_entries) \
+				     < le16_to_cpu((__path__)->p_hdr->eh_max))
+#define EXT_LAST_EXTENT(__hdr__) \
+	(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
+#define EXT_LAST_INDEX(__hdr__) \
+	(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
+#define EXT_MAX_EXTENT(__hdr__) \
+	(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
+#define EXT_MAX_INDEX(__hdr__) \
+	(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
+
+static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
+{
+	return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
+}
+
+static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
+{
+	return (struct ext4_extent_header *) bh->b_data;
+}
+
+static inline unsigned short ext_depth(struct inode *inode)
+{
+	return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
+}
+
+static inline void ext4_ext_mark_unwritten(struct ext4_extent *ext)
+{
+	/* We can not have an unwritten extent of zero length! */
+	BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
+	ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
+}
+
+static inline int ext4_ext_is_unwritten(struct ext4_extent *ext)
+{
+	/* Extent with ee_len of 0x8000 is treated as an initialized extent */
+	return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
+}
+
+static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
+{
+	return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
+		le16_to_cpu(ext->ee_len) :
+		(le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
+}
+
+static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
+{
+	ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
+}
+
+/*
+ * ext4_ext_pblock:
+ * combine low and high parts of physical block number into ext4_fsblk_t
+ */
+static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
+{
+	ext4_fsblk_t block;
+
+	block = le32_to_cpu(ex->ee_start_lo);
+	block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
+	return block;
+}
+
+/*
+ * ext4_idx_pblock:
+ * combine low and high parts of a leaf physical block number into ext4_fsblk_t
+ */
+static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix)
+{
+	ext4_fsblk_t block;
+
+	block = le32_to_cpu(ix->ei_leaf_lo);
+	block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
+	return block;
+}
+
+/*
+ * ext4_ext_store_pblock:
+ * stores a large physical block number into an extent struct,
+ * breaking it into parts
+ */
+static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
+					 ext4_fsblk_t pb)
+{
+	ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
+	ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
+				      0xffff);
+}
+
+/*
+ * ext4_idx_store_pblock:
+ * stores a large physical block number into an index struct,
+ * breaking it into parts
+ */
+static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
+					 ext4_fsblk_t pb)
+{
+	ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
+	ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
+				     0xffff);
+}
+
+#define ext4_ext_dirty(handle, inode, path) \
+		__ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
+int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
+		     struct inode *inode, struct ext4_ext_path *path);
+
+#endif /* _EXT4_EXTENTS */
+

fs/ext4/ext4_jbd2.c

@@ -0,0 +1,321 @@
+/*
+ * Interface between ext4 and JBD
+ */
+
+#include "ext4_jbd2.h"
+
+#include <trace/events/ext4.h>
+
+/* Just increment the non-pointer handle value */
+static handle_t *ext4_get_nojournal(void)
+{
+	handle_t *handle = current->journal_info;
+	unsigned long ref_cnt = (unsigned long)handle;
+
+	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
+
+	ref_cnt++;
+	handle = (handle_t *)ref_cnt;
+
+	current->journal_info = handle;
+	return handle;
+}
+
+
+/* Decrement the non-pointer handle value */
+static void ext4_put_nojournal(handle_t *handle)
+{
+	unsigned long ref_cnt = (unsigned long)handle;
+
+	BUG_ON(ref_cnt == 0);
+
+	ref_cnt--;
+	handle = (handle_t *)ref_cnt;
+
+	current->journal_info = handle;
+}
+
+/*
+ * Wrappers for jbd2_journal_start/end.
+ */
+static int ext4_journal_check_start(struct super_block *sb)
+{
+	journal_t *journal;
+
+	might_sleep();
+	if (sb->s_flags & MS_RDONLY && !ext4_journal_current_handle())
+		return -EROFS;
+	WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE);
+	journal = EXT4_SB(sb)->s_journal;
+	/*
+	 * Special case here: if the journal has aborted behind our
+	 * backs (eg. EIO in the commit thread), then we still need to
+	 * take the FS itself readonly cleanly.
+	 */
+	if (journal && is_journal_aborted(journal)) {
+		ext4_abort(sb, "Detected aborted journal");
+		return -EROFS;
+	}
+	return 0;
+}
+
+handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
+				  int type, int blocks, int rsv_blocks)
+{
+	journal_t *journal;
+	int err;
+
+	trace_ext4_journal_start(sb, blocks, rsv_blocks, _RET_IP_);
+	err = ext4_journal_check_start(sb);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	journal = EXT4_SB(sb)->s_journal;
+	if (!journal)
+		return ext4_get_nojournal();
+	return jbd2__journal_start(journal, blocks, rsv_blocks, GFP_NOFS,
+				   type, line);
+}
+
+int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
+{
+	struct super_block *sb;
+	int err;
+	int rc;
+
+	if (!ext4_handle_valid(handle)) {
+		ext4_put_nojournal(handle);
+		return 0;
+	}
+	sb = handle->h_transaction->t_journal->j_private;
+	err = handle->h_err;
+	rc = jbd2_journal_stop(handle);
+
+	if (!err)
+		err = rc;
+	if (err)
+		__ext4_std_error(sb, where, line, err);
+	return err;
+}
+
+handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line,
+					int type)
+{
+	struct super_block *sb;
+	int err;
+
+	if (!ext4_handle_valid(handle))
+		return ext4_get_nojournal();
+
+	sb = handle->h_journal->j_private;
+	trace_ext4_journal_start_reserved(sb, handle->h_buffer_credits,
+					  _RET_IP_);
+	err = ext4_journal_check_start(sb);
+	if (err < 0) {
+		jbd2_journal_free_reserved(handle);
+		return ERR_PTR(err);
+	}
+
+	err = jbd2_journal_start_reserved(handle, type, line);
+	if (err < 0)
+		return ERR_PTR(err);
+	return handle;
+}
+
+static void ext4_journal_abort_handle(const char *caller, unsigned int line,
+				      const char *err_fn,
+				      struct buffer_head *bh,
+				      handle_t *handle, int err)
+{
+	char nbuf[16];
+	const char *errstr = ext4_decode_error(NULL, err, nbuf);
+
+	BUG_ON(!ext4_handle_valid(handle));
+
+	if (bh)
+		BUFFER_TRACE(bh, "abort");
+
+	if (!handle->h_err)
+		handle->h_err = err;
+
+	if (is_handle_aborted(handle))
+		return;
+
+	printk(KERN_ERR "EXT4-fs: %s:%d: aborting transaction: %s in %s\n",
+	       caller, line, errstr, err_fn);
+
+	jbd2_journal_abort_handle(handle);
+}
+
+int __ext4_journal_get_write_access(const char *where, unsigned int line,
+				    handle_t *handle, struct buffer_head *bh)
+{
+	int err = 0;
+
+	might_sleep();
+
+	if (ext4_handle_valid(handle)) {
+		err = jbd2_journal_get_write_access(handle, bh);
+		if (err)
+			ext4_journal_abort_handle(where, line, __func__, bh,
+						  handle, err);
+	}
+	return err;
+}
+
+/*
+ * The ext4 forget function must perform a revoke if we are freeing data
+ * which has been journaled.  Metadata (eg. indirect blocks) must be
+ * revoked in all cases.
+ *
+ * "bh" may be NULL: a metadata block may have been freed from memory
+ * but there may still be a record of it in the journal, and that record
+ * still needs to be revoked.
+ *
+ * If the handle isn't valid we're not journaling, but we still need to
+ * call into ext4_journal_revoke() to put the buffer head.
+ */
+int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
+		  int is_metadata, struct inode *inode,
+		  struct buffer_head *bh, ext4_fsblk_t blocknr)
+{
+	int err;
+
+	might_sleep();
+
+	trace_ext4_forget(inode, is_metadata, blocknr);
+	BUFFER_TRACE(bh, "enter");
+
+	jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
+		  "data mode %x\n",
+		  bh, is_metadata, inode->i_mode,
+		  test_opt(inode->i_sb, DATA_FLAGS));
+
+	/* In the no journal case, we can just do a bforget and return */
+	if (!ext4_handle_valid(handle)) {
+		bforget(bh);
+		return 0;
+	}
+
+	/* Never use the revoke function if we are doing full data
+	 * journaling: there is no need to, and a V1 superblock won't
+	 * support it.  Otherwise, only skip the revoke on un-journaled
+	 * data blocks. */
+
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
+	    (!is_metadata && !ext4_should_journal_data(inode))) {
+		if (bh) {
+			BUFFER_TRACE(bh, "call jbd2_journal_forget");
+			err = jbd2_journal_forget(handle, bh);
+			if (err)
+				ext4_journal_abort_handle(where, line, __func__,
+							  bh, handle, err);
+			return err;
+		}
+		return 0;
+	}
+
+	/*
+	 * data!=journal && (is_metadata || should_journal_data(inode))
+	 */
+	BUFFER_TRACE(bh, "call jbd2_journal_revoke");
+	err = jbd2_journal_revoke(handle, blocknr, bh);
+	if (err) {
+		ext4_journal_abort_handle(where, line, __func__,
+					  bh, handle, err);
+		__ext4_abort(inode->i_sb, where, line,
+			   "error %d when attempting revoke", err);
+	}
+	BUFFER_TRACE(bh, "exit");
+	return err;
+}
+
+int __ext4_journal_get_create_access(const char *where, unsigned int line,
+				handle_t *handle, struct buffer_head *bh)
+{
+	int err = 0;
+
+	if (ext4_handle_valid(handle)) {
+		err = jbd2_journal_get_create_access(handle, bh);
+		if (err)
+			ext4_journal_abort_handle(where, line, __func__,
+						  bh, handle, err);
+	}
+	return err;
+}
+
+int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
+				 handle_t *handle, struct inode *inode,
+				 struct buffer_head *bh)
+{
+	int err = 0;
+
+	might_sleep();
+
+	set_buffer_meta(bh);
+	set_buffer_prio(bh);
+	if (ext4_handle_valid(handle)) {
+		err = jbd2_journal_dirty_metadata(handle, bh);
+		/* Errors can only happen due to aborted journal or a nasty bug */
+		if (!is_handle_aborted(handle) && WARN_ON_ONCE(err)) {
+			ext4_journal_abort_handle(where, line, __func__, bh,
+						  handle, err);
+			if (inode == NULL) {
+				pr_err("EXT4: jbd2_journal_dirty_metadata "
+				       "failed: handle type %u started at "
+				       "line %u, credits %u/%u, errcode %d",
+				       handle->h_type,
+				       handle->h_line_no,
+				       handle->h_requested_credits,
+				       handle->h_buffer_credits, err);
+				return err;
+			}
+			ext4_error_inode(inode, where, line,
+					 bh->b_blocknr,
+					 "journal_dirty_metadata failed: "
+					 "handle type %u started at line %u, "
+					 "credits %u/%u, errcode %d",
+					 handle->h_type,
+					 handle->h_line_no,
+					 handle->h_requested_credits,
+					 handle->h_buffer_credits, err);
+		}
+	} else {
+		if (inode)
+			mark_buffer_dirty_inode(bh, inode);
+		else
+			mark_buffer_dirty(bh);
+		if (inode && inode_needs_sync(inode)) {
+			sync_dirty_buffer(bh);
+			if (buffer_req(bh) && !buffer_uptodate(bh)) {
+				struct ext4_super_block *es;
+
+				es = EXT4_SB(inode->i_sb)->s_es;
+				es->s_last_error_block =
+					cpu_to_le64(bh->b_blocknr);
+				ext4_error_inode(inode, where, line,
+						 bh->b_blocknr,
+					"IO error syncing itable block");
+				err = -EIO;
+			}
+		}
+	}
+	return err;
+}
+
+int __ext4_handle_dirty_super(const char *where, unsigned int line,
+			      handle_t *handle, struct super_block *sb)
+{
+	struct buffer_head *bh = EXT4_SB(sb)->s_sbh;
+	int err = 0;
+
+	ext4_superblock_csum_set(sb);
+	if (ext4_handle_valid(handle)) {
+		err = jbd2_journal_dirty_metadata(handle, bh);
+		if (err)
+			ext4_journal_abort_handle(where, line, __func__,
+						  bh, handle, err);
+	} else
+		mark_buffer_dirty(bh);
+	return err;
+}

fs/ext4/ext4_jbd2.h

@@ -0,0 +1,450 @@
+/*
+ * ext4_jbd2.h
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
+ *
+ * Copyright 1998--1999 Red Hat corp --- All Rights Reserved
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * Ext4-specific journaling extensions.
+ */
+
+#ifndef _EXT4_JBD2_H
+#define _EXT4_JBD2_H
+
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include "ext4.h"
+
+#define EXT4_JOURNAL(inode)	(EXT4_SB((inode)->i_sb)->s_journal)
+
+/* Define the number of blocks we need to account to a transaction to
+ * modify one block of data.
+ *
+ * We may have to touch one inode, one bitmap buffer, up to three
+ * indirection blocks, the group and superblock summaries, and the data
+ * block to complete the transaction.
+ *
+ * For extents-enabled fs we may have to allocate and modify up to
+ * 5 levels of tree, data block (for each of these we need bitmap + group
+ * summaries), root which is stored in the inode, sb
+ */
+
+#define EXT4_SINGLEDATA_TRANS_BLOCKS(sb)				\
+	(EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)   \
+	 ? 20U : 8U)
+
+/* Extended attribute operations touch at most two data buffers,
+ * two bitmap buffers, and two group summaries, in addition to the inode
+ * and the superblock, which are already accounted for. */
+
+#define EXT4_XATTR_TRANS_BLOCKS		6U
+
+/* Define the minimum size for a transaction which modifies data.  This
+ * needs to take into account the fact that we may end up modifying two
+ * quota files too (one for the group, one for the user quota).  The
+ * superblock only gets updated once, of course, so don't bother
+ * counting that again for the quota updates. */
+
+#define EXT4_DATA_TRANS_BLOCKS(sb)	(EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + \
+					 EXT4_XATTR_TRANS_BLOCKS - 2 + \
+					 EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
+
+/*
+ * Define the number of metadata blocks we need to account to modify data.
+ *
+ * This include super block, inode block, quota blocks and xattr blocks
+ */
+#define EXT4_META_TRANS_BLOCKS(sb)	(EXT4_XATTR_TRANS_BLOCKS + \
+					EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
+
+/* Define an arbitrary limit for the amount of data we will anticipate
+ * writing to any given transaction.  For unbounded transactions such as
+ * write(2) and truncate(2) we can write more than this, but we always
+ * start off at the maximum transaction size and grow the transaction
+ * optimistically as we go. */
+
+#define EXT4_MAX_TRANS_DATA		64U
+
+/* We break up a large truncate or write transaction once the handle's
+ * buffer credits gets this low, we need either to extend the
+ * transaction or to start a new one.  Reserve enough space here for
+ * inode, bitmap, superblock, group and indirection updates for at least
+ * one block, plus two quota updates.  Quota allocations are not
+ * needed. */
+
+#define EXT4_RESERVE_TRANS_BLOCKS	12U
+
+#define EXT4_INDEX_EXTRA_TRANS_BLOCKS	8
+
+#ifdef CONFIG_QUOTA
+/* Amount of blocks needed for quota update - we know that the structure was
+ * allocated so we need to update only data block */
+#define EXT4_QUOTA_TRANS_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
+		EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) ?\
+		1 : 0)
+/* Amount of blocks needed for quota insert/delete - we do some block writes
+ * but inode, sb and group updates are done only once */
+#define EXT4_QUOTA_INIT_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
+		EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) ?\
+		(DQUOT_INIT_ALLOC*(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)\
+		 +3+DQUOT_INIT_REWRITE) : 0)
+
+#define EXT4_QUOTA_DEL_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
+		EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) ?\
+		(DQUOT_DEL_ALLOC*(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)\
+		 +3+DQUOT_DEL_REWRITE) : 0)
+#else
+#define EXT4_QUOTA_TRANS_BLOCKS(sb) 0
+#define EXT4_QUOTA_INIT_BLOCKS(sb) 0
+#define EXT4_QUOTA_DEL_BLOCKS(sb) 0
+#endif
+#define EXT4_MAXQUOTAS_TRANS_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_TRANS_BLOCKS(sb))
+#define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
+#define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))
+
+static inline int ext4_jbd2_credits_xattr(struct inode *inode)
+{
+	int credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
+
+	/*
+	 * In case of inline data, we may push out the data to a block,
+	 * so we need to reserve credits for this eventuality
+	 */
+	if (ext4_has_inline_data(inode))
+		credits += ext4_writepage_trans_blocks(inode) + 1;
+	return credits;
+}
+
+
+/*
+ * Ext4 handle operation types -- for logging purposes
+ */
+#define EXT4_HT_MISC             0
+#define EXT4_HT_INODE            1
+#define EXT4_HT_WRITE_PAGE       2
+#define EXT4_HT_MAP_BLOCKS       3
+#define EXT4_HT_DIR              4
+#define EXT4_HT_TRUNCATE         5
+#define EXT4_HT_QUOTA            6
+#define EXT4_HT_RESIZE           7
+#define EXT4_HT_MIGRATE          8
+#define EXT4_HT_MOVE_EXTENTS     9
+#define EXT4_HT_XATTR           10
+#define EXT4_HT_EXT_CONVERT     11
+#define EXT4_HT_MAX             12
+
+/**
+ *   struct ext4_journal_cb_entry - Base structure for callback information.
+ *
+ *   This struct is a 'seed' structure for a using with your own callback
+ *   structs. If you are using callbacks you must allocate one of these
+ *   or another struct of your own definition which has this struct
+ *   as it's first element and pass it to ext4_journal_callback_add().
+ */
+struct ext4_journal_cb_entry {
+	/* list information for other callbacks attached to the same handle */
+	struct list_head jce_list;
+
+	/*  Function to call with this callback structure */
+	void (*jce_func)(struct super_block *sb,
+			 struct ext4_journal_cb_entry *jce, int error);
+
+	/* user data goes here */
+};
+
+/**
+ * ext4_journal_callback_add: add a function to call after transaction commit
+ * @handle: active journal transaction handle to register callback on
+ * @func: callback function to call after the transaction has committed:
+ *        @sb: superblock of current filesystem for transaction
+ *        @jce: returned journal callback data
+ *        @rc: journal state at commit (0 = transaction committed properly)
+ * @jce: journal callback data (internal and function private data struct)
+ *
+ * The registered function will be called in the context of the journal thread
+ * after the transaction for which the handle was created has completed.
+ *
+ * No locks are held when the callback function is called, so it is safe to
+ * call blocking functions from within the callback, but the callback should
+ * not block or run for too long, or the filesystem will be blocked waiting for
+ * the next transaction to commit. No journaling functions can be used, or
+ * there is a risk of deadlock.
+ *
+ * There is no guaranteed calling order of multiple registered callbacks on
+ * the same transaction.
+ */
+static inline void ext4_journal_callback_add(handle_t *handle,
+			void (*func)(struct super_block *sb,
+				     struct ext4_journal_cb_entry *jce,
+				     int rc),
+			struct ext4_journal_cb_entry *jce)
+{
+	struct ext4_sb_info *sbi =
+			EXT4_SB(handle->h_transaction->t_journal->j_private);
+
+	/* Add the jce to transaction's private list */
+	jce->jce_func = func;
+	spin_lock(&sbi->s_md_lock);
+	list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);
+	spin_unlock(&sbi->s_md_lock);
+}
+
+/**
+ * ext4_journal_callback_del: delete a registered callback
+ * @handle: active journal transaction handle on which callback was registered
+ * @jce: registered journal callback entry to unregister
+ * Return true if object was successfully removed
+ */
+static inline bool ext4_journal_callback_try_del(handle_t *handle,
+					     struct ext4_journal_cb_entry *jce)
+{
+	bool deleted;
+	struct ext4_sb_info *sbi =
+			EXT4_SB(handle->h_transaction->t_journal->j_private);
+
+	spin_lock(&sbi->s_md_lock);
+	deleted = !list_empty(&jce->jce_list);
+	list_del_init(&jce->jce_list);
+	spin_unlock(&sbi->s_md_lock);
+	return deleted;
+}
+
+int
+ext4_mark_iloc_dirty(handle_t *handle,
+		     struct inode *inode,
+		     struct ext4_iloc *iloc);
+
+/*
+ * On success, We end up with an outstanding reference count against
+ * iloc->bh.  This _must_ be cleaned up later.
+ */
+
+int ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
+			struct ext4_iloc *iloc);
+
+int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode);
+
+/*
+ * Wrapper functions with which ext4 calls into JBD.
+ */
+int __ext4_journal_get_write_access(const char *where, unsigned int line,
+				    handle_t *handle, struct buffer_head *bh);
+
+int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
+		  int is_metadata, struct inode *inode,
+		  struct buffer_head *bh, ext4_fsblk_t blocknr);
+
+int __ext4_journal_get_create_access(const char *where, unsigned int line,
+				handle_t *handle, struct buffer_head *bh);
+
+int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
+				 handle_t *handle, struct inode *inode,
+				 struct buffer_head *bh);
+
+int __ext4_handle_dirty_super(const char *where, unsigned int line,
+			      handle_t *handle, struct super_block *sb);
+
+#define ext4_journal_get_write_access(handle, bh) \
+	__ext4_journal_get_write_access(__func__, __LINE__, (handle), (bh))
+#define ext4_forget(handle, is_metadata, inode, bh, block_nr) \
+	__ext4_forget(__func__, __LINE__, (handle), (is_metadata), (inode), \
+		      (bh), (block_nr))
+#define ext4_journal_get_create_access(handle, bh) \
+	__ext4_journal_get_create_access(__func__, __LINE__, (handle), (bh))
+#define ext4_handle_dirty_metadata(handle, inode, bh) \
+	__ext4_handle_dirty_metadata(__func__, __LINE__, (handle), (inode), \
+				     (bh))
+#define ext4_handle_dirty_super(handle, sb) \
+	__ext4_handle_dirty_super(__func__, __LINE__, (handle), (sb))
+
+handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
+				  int type, int blocks, int rsv_blocks);
+int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle);
+
+#define EXT4_NOJOURNAL_MAX_REF_COUNT ((unsigned long) 4096)
+
+/* Note:  Do not use this for NULL handles.  This is only to determine if
+ * a properly allocated handle is using a journal or not. */
+static inline int ext4_handle_valid(handle_t *handle)
+{
+	if ((unsigned long)handle < EXT4_NOJOURNAL_MAX_REF_COUNT)
+		return 0;
+	return 1;
+}
+
+static inline void ext4_handle_sync(handle_t *handle)
+{
+	if (ext4_handle_valid(handle))
+		handle->h_sync = 1;
+}
+
+static inline int ext4_handle_is_aborted(handle_t *handle)
+{
+	if (ext4_handle_valid(handle))
+		return is_handle_aborted(handle);
+	return 0;
+}
+
+static inline int ext4_handle_has_enough_credits(handle_t *handle, int needed)
+{
+	if (ext4_handle_valid(handle) && handle->h_buffer_credits < needed)
+		return 0;
+	return 1;
+}
+
+#define ext4_journal_start_sb(sb, type, nblocks)			\
+	__ext4_journal_start_sb((sb), __LINE__, (type), (nblocks), 0)
+
+#define ext4_journal_start(inode, type, nblocks)			\
+	__ext4_journal_start((inode), __LINE__, (type), (nblocks), 0)
+
+#define ext4_journal_start_with_reserve(inode, type, blocks, rsv_blocks) \
+	__ext4_journal_start((inode), __LINE__, (type), (blocks), (rsv_blocks))
+
+static inline handle_t *__ext4_journal_start(struct inode *inode,
+					     unsigned int line, int type,
+					     int blocks, int rsv_blocks)
+{
+	return __ext4_journal_start_sb(inode->i_sb, line, type, blocks,
+				       rsv_blocks);
+}
+
+#define ext4_journal_stop(handle) \
+	__ext4_journal_stop(__func__, __LINE__, (handle))
+
+#define ext4_journal_start_reserved(handle, type) \
+	__ext4_journal_start_reserved((handle), __LINE__, (type))
+
+handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line,
+					int type);
+
+static inline void ext4_journal_free_reserved(handle_t *handle)
+{
+	if (ext4_handle_valid(handle))
+		jbd2_journal_free_reserved(handle);
+}
+
+static inline handle_t *ext4_journal_current_handle(void)
+{
+	return journal_current_handle();
+}
+
+static inline int ext4_journal_extend(handle_t *handle, int nblocks)
+{
+	if (ext4_handle_valid(handle))
+		return jbd2_journal_extend(handle, nblocks);
+	return 0;
+}
+
+static inline int ext4_journal_restart(handle_t *handle, int nblocks)
+{
+	if (ext4_handle_valid(handle))
+		return jbd2_journal_restart(handle, nblocks);
+	return 0;
+}
+
+static inline int ext4_journal_blocks_per_page(struct inode *inode)
+{
+	if (EXT4_JOURNAL(inode) != NULL)
+		return jbd2_journal_blocks_per_page(inode);
+	return 0;
+}
+
+static inline int ext4_journal_force_commit(journal_t *journal)
+{
+	if (journal)
+		return jbd2_journal_force_commit(journal);
+	return 0;
+}
+
+static inline int ext4_jbd2_file_inode(handle_t *handle, struct inode *inode)
+{
+	if (ext4_handle_valid(handle))
+		return jbd2_journal_file_inode(handle, EXT4_I(inode)->jinode);
+	return 0;
+}
+
+static inline void ext4_update_inode_fsync_trans(handle_t *handle,
+						 struct inode *inode,
+						 int datasync)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (ext4_handle_valid(handle)) {
+		ei->i_sync_tid = handle->h_transaction->t_tid;
+		if (datasync)
+			ei->i_datasync_tid = handle->h_transaction->t_tid;
+	}
+}
+
+/* super.c */
+int ext4_force_commit(struct super_block *sb);
+
+/*
+ * Ext4 inode journal modes
+ */
+#define EXT4_INODE_JOURNAL_DATA_MODE	0x01 /* journal data mode */
+#define EXT4_INODE_ORDERED_DATA_MODE	0x02 /* ordered data mode */
+#define EXT4_INODE_WRITEBACK_DATA_MODE	0x04 /* writeback data mode */
+
+static inline int ext4_inode_journal_mode(struct inode *inode)
+{
+	if (EXT4_JOURNAL(inode) == NULL)
+		return EXT4_INODE_WRITEBACK_DATA_MODE;	/* writeback */
+	/* We do not support data journalling with delayed allocation */
+	if (!S_ISREG(inode->i_mode) ||
+	    test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
+		return EXT4_INODE_JOURNAL_DATA_MODE;	/* journal data */
+	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA) &&
+	    !test_opt(inode->i_sb, DELALLOC))
+		return EXT4_INODE_JOURNAL_DATA_MODE;	/* journal data */
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
+		return EXT4_INODE_ORDERED_DATA_MODE;	/* ordered */
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
+		return EXT4_INODE_WRITEBACK_DATA_MODE;	/* writeback */
+	else
+		BUG();
+}
+
+static inline int ext4_should_journal_data(struct inode *inode)
+{
+	return ext4_inode_journal_mode(inode) & EXT4_INODE_JOURNAL_DATA_MODE;
+}
+
+static inline int ext4_should_order_data(struct inode *inode)
+{
+	return ext4_inode_journal_mode(inode) & EXT4_INODE_ORDERED_DATA_MODE;
+}
+
+static inline int ext4_should_writeback_data(struct inode *inode)
+{
+	return ext4_inode_journal_mode(inode) & EXT4_INODE_WRITEBACK_DATA_MODE;
+}
+
+/*
+ * This function controls whether or not we should try to go down the
+ * dioread_nolock code paths, which makes it safe to avoid taking
+ * i_mutex for direct I/O reads.  This only works for extent-based
+ * files, and it doesn't work if data journaling is enabled, since the
+ * dioread_nolock code uses b_private to pass information back to the
+ * I/O completion handler, and this conflicts with the jbd's use of
+ * b_private.
+ */
+static inline int ext4_should_dioread_nolock(struct inode *inode)
+{
+	if (!test_opt(inode->i_sb, DIOREAD_NOLOCK))
+		return 0;
+	if (!S_ISREG(inode->i_mode))
+		return 0;
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		return 0;
+	if (ext4_should_journal_data(inode))
+		return 0;
+	return 1;
+}
+
+#endif	/* _EXT4_JBD2_H */

fs/ext4/extents_status.h

@@ -0,0 +1,157 @@
+/*
+ *  fs/ext4/extents_status.h
+ *
+ * Written by Yongqiang Yang <xiaoqiangnk@gmail.com>
+ * Modified by
+ *	Allison Henderson <achender@linux.vnet.ibm.com>
+ *	Zheng Liu <wenqing.lz@taobao.com>
+ *
+ */
+
+#ifndef _EXT4_EXTENTS_STATUS_H
+#define _EXT4_EXTENTS_STATUS_H
+
+/*
+ * Turn on ES_DEBUG__ to get lots of info about extent status operations.
+ */
+#ifdef ES_DEBUG__
+#define es_debug(fmt, ...)	printk(fmt, ##__VA_ARGS__)
+#else
+#define es_debug(fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+#endif
+
+/*
+ * With ES_AGGRESSIVE_TEST defined, the result of es caching will be
+ * checked with old map_block's result.
+ */
+#define ES_AGGRESSIVE_TEST__
+
+/*
+ * These flags live in the high bits of extent_status.es_pblk
+ */
+#define ES_SHIFT	60
+
+#define EXTENT_STATUS_WRITTEN	(1 << 3)
+#define EXTENT_STATUS_UNWRITTEN (1 << 2)
+#define EXTENT_STATUS_DELAYED	(1 << 1)
+#define EXTENT_STATUS_HOLE	(1 << 0)
+
+#define EXTENT_STATUS_FLAGS	(EXTENT_STATUS_WRITTEN | \
+				 EXTENT_STATUS_UNWRITTEN | \
+				 EXTENT_STATUS_DELAYED | \
+				 EXTENT_STATUS_HOLE)
+
+#define ES_WRITTEN		(1ULL << 63)
+#define ES_UNWRITTEN		(1ULL << 62)
+#define ES_DELAYED		(1ULL << 61)
+#define ES_HOLE			(1ULL << 60)
+
+#define ES_MASK			(ES_WRITTEN | ES_UNWRITTEN | \
+				 ES_DELAYED | ES_HOLE)
+
+struct ext4_sb_info;
+struct ext4_extent;
+
+struct extent_status {
+	struct rb_node rb_node;
+	ext4_lblk_t es_lblk;	/* first logical block extent covers */
+	ext4_lblk_t es_len;	/* length of extent in block */
+	ext4_fsblk_t es_pblk;	/* first physical block */
+};
+
+struct ext4_es_tree {
+	struct rb_root root;
+	struct extent_status *cache_es;	/* recently accessed extent */
+};
+
+struct ext4_es_stats {
+	unsigned long es_stats_last_sorted;
+	unsigned long es_stats_shrunk;
+	unsigned long es_stats_cache_hits;
+	unsigned long es_stats_cache_misses;
+	u64 es_stats_scan_time;
+	u64 es_stats_max_scan_time;
+	struct percpu_counter es_stats_all_cnt;
+	struct percpu_counter es_stats_lru_cnt;
+};
+
+extern int __init ext4_init_es(void);
+extern void ext4_exit_es(void);
+extern void ext4_es_init_tree(struct ext4_es_tree *tree);
+
+extern int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
+				 ext4_lblk_t len, ext4_fsblk_t pblk,
+				 unsigned int status);
+extern void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
+				 ext4_lblk_t len, ext4_fsblk_t pblk,
+				 unsigned int status);
+extern int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
+				 ext4_lblk_t len);
+extern void ext4_es_find_delayed_extent_range(struct inode *inode,
+					ext4_lblk_t lblk, ext4_lblk_t end,
+					struct extent_status *es);
+extern int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
+				 struct extent_status *es);
+
+static inline int ext4_es_is_written(struct extent_status *es)
+{
+	return (es->es_pblk & ES_WRITTEN) != 0;
+}
+
+static inline int ext4_es_is_unwritten(struct extent_status *es)
+{
+	return (es->es_pblk & ES_UNWRITTEN) != 0;
+}
+
+static inline int ext4_es_is_delayed(struct extent_status *es)
+{
+	return (es->es_pblk & ES_DELAYED) != 0;
+}
+
+static inline int ext4_es_is_hole(struct extent_status *es)
+{
+	return (es->es_pblk & ES_HOLE) != 0;
+}
+
+static inline unsigned int ext4_es_status(struct extent_status *es)
+{
+	return es->es_pblk >> ES_SHIFT;
+}
+
+static inline ext4_fsblk_t ext4_es_pblock(struct extent_status *es)
+{
+	return es->es_pblk & ~ES_MASK;
+}
+
+static inline void ext4_es_store_pblock(struct extent_status *es,
+					ext4_fsblk_t pb)
+{
+	ext4_fsblk_t block;
+
+	block = (pb & ~ES_MASK) | (es->es_pblk & ES_MASK);
+	es->es_pblk = block;
+}
+
+static inline void ext4_es_store_status(struct extent_status *es,
+					unsigned int status)
+{
+	es->es_pblk = (((ext4_fsblk_t)
+			(status & EXTENT_STATUS_FLAGS) << ES_SHIFT) |
+		       (es->es_pblk & ~ES_MASK));
+}
+
+static inline void ext4_es_store_pblock_status(struct extent_status *es,
+					       ext4_fsblk_t pb,
+					       unsigned int status)
+{
+	es->es_pblk = (((ext4_fsblk_t)
+			(status & EXTENT_STATUS_FLAGS) << ES_SHIFT) |
+		       (pb & ~ES_MASK));
+}
+
+extern int ext4_es_register_shrinker(struct ext4_sb_info *sbi);
+extern void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi);
+extern void ext4_es_lru_add(struct inode *inode);
+extern void ext4_es_lru_del(struct inode *inode);
+
+#endif /* _EXT4_EXTENTS_STATUS_H */

fs/ext4/file.c

@@ -0,0 +1,614 @@
+/*
+ *  linux/fs/ext4/file.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/file.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 fs regular file handling primitives
+ *
+ *  64-bit file support on 64-bit platforms by Jakub Jelinek
+ *	(jj@sunsite.ms.mff.cuni.cz)
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/mount.h>
+#include <linux/path.h>
+#include <linux/aio.h>
+#include <linux/quotaops.h>
+#include <linux/pagevec.h>
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * Called when an inode is released. Note that this is different
+ * from ext4_file_open: open gets called at every open, but release
+ * gets called only when /all/ the files are closed.
+ */
+static int ext4_release_file(struct inode *inode, struct file *filp)
+{
+	if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
+		ext4_alloc_da_blocks(inode);
+		ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
+	}
+	/* if we are the last writer on the inode, drop the block reservation */
+	if ((filp->f_mode & FMODE_WRITE) &&
+			(atomic_read(&inode->i_writecount) == 1) &&
+		        !EXT4_I(inode)->i_reserved_data_blocks)
+	{
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ext4_discard_preallocations(inode);
+		up_write(&EXT4_I(inode)->i_data_sem);
+	}
+	if (is_dx(inode) && filp->private_data)
+		ext4_htree_free_dir_info(filp->private_data);
+
+	return 0;
+}
+
+static void ext4_unwritten_wait(struct inode *inode)
+{
+	wait_queue_head_t *wq = ext4_ioend_wq(inode);
+
+	wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0));
+}
+
+/*
+ * This tests whether the IO in question is block-aligned or not.
+ * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
+ * are converted to written only after the IO is complete.  Until they are
+ * mapped, these blocks appear as holes, so dio_zero_block() will assume that
+ * it needs to zero out portions of the start and/or end block.  If 2 AIO
+ * threads are at work on the same unwritten block, they must be synchronized
+ * or one thread will zero the other's data, causing corruption.
+ */
+static int
+ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos)
+{
+	struct super_block *sb = inode->i_sb;
+	int blockmask = sb->s_blocksize - 1;
+
+	if (pos >= i_size_read(inode))
+		return 0;
+
+	if ((pos | iov_iter_alignment(from)) & blockmask)
+		return 1;
+
+	return 0;
+}
+
+static ssize_t
+ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct mutex *aio_mutex = NULL;
+	struct blk_plug plug;
+	int o_direct = file->f_flags & O_DIRECT;
+	int overwrite = 0;
+	size_t length = iov_iter_count(from);
+	ssize_t ret;
+	loff_t pos = iocb->ki_pos;
+
+	/*
+	 * Unaligned direct AIO must be serialized; see comment above
+	 * In the case of O_APPEND, assume that we must always serialize
+	 */
+	if (o_direct &&
+	    ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
+	    !is_sync_kiocb(iocb) &&
+	    (file->f_flags & O_APPEND ||
+	     ext4_unaligned_aio(inode, from, pos))) {
+		aio_mutex = ext4_aio_mutex(inode);
+		mutex_lock(aio_mutex);
+		ext4_unwritten_wait(inode);
+	}
+
+	mutex_lock(&inode->i_mutex);
+	if (file->f_flags & O_APPEND)
+		iocb->ki_pos = pos = i_size_read(inode);
+
+	/*
+	 * If we have encountered a bitmap-format file, the size limit
+	 * is smaller than s_maxbytes, which is for extent-mapped files.
+	 */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+		if ((pos > sbi->s_bitmap_maxbytes) ||
+		    (pos == sbi->s_bitmap_maxbytes && length > 0)) {
+			mutex_unlock(&inode->i_mutex);
+			ret = -EFBIG;
+			goto errout;
+		}
+
+		if (pos + length > sbi->s_bitmap_maxbytes)
+			iov_iter_truncate(from, sbi->s_bitmap_maxbytes - pos);
+	}
+
+	iocb->private = &overwrite;
+	if (o_direct) {
+		blk_start_plug(&plug);
+
+
+		/* check whether we do a DIO overwrite or not */
+		if (ext4_should_dioread_nolock(inode) && !aio_mutex &&
+		    !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
+			struct ext4_map_blocks map;
+			unsigned int blkbits = inode->i_blkbits;
+			int err, len;
+
+			map.m_lblk = pos >> blkbits;
+			map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
+				- map.m_lblk;
+			len = map.m_len;
+
+			err = ext4_map_blocks(NULL, inode, &map, 0);
+			/*
+			 * 'err==len' means that all of blocks has
+			 * been preallocated no matter they are
+			 * initialized or not.  For excluding
+			 * unwritten extents, we need to check
+			 * m_flags.  There are two conditions that
+			 * indicate for initialized extents.  1) If we
+			 * hit extent cache, EXT4_MAP_MAPPED flag is
+			 * returned; 2) If we do a real lookup,
+			 * non-flags are returned.  So we should check
+			 * these two conditions.
+			 */
+			if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
+				overwrite = 1;
+		}
+	}
+
+	ret = __generic_file_write_iter(iocb, from);
+	mutex_unlock(&inode->i_mutex);
+
+	if (ret > 0) {
+		ssize_t err;
+
+		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
+		if (err < 0)
+			ret = err;
+	}
+	if (o_direct)
+		blk_finish_plug(&plug);
+
+errout:
+	if (aio_mutex)
+		mutex_unlock(aio_mutex);
+	return ret;
+}
+
+static const struct vm_operations_struct ext4_file_vm_ops = {
+	.fault		= filemap_fault,
+	.map_pages	= filemap_map_pages,
+	.page_mkwrite   = ext4_page_mkwrite,
+	.remap_pages	= generic_file_remap_pages,
+};
+
+static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	file_accessed(file);
+	vma->vm_ops = &ext4_file_vm_ops;
+	return 0;
+}
+
+static int ext4_file_open(struct inode * inode, struct file * filp)
+{
+	struct super_block *sb = inode->i_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct vfsmount *mnt = filp->f_path.mnt;
+	struct path path;
+	char buf[64], *cp;
+
+	if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
+		     !(sb->s_flags & MS_RDONLY))) {
+		sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
+		/*
+		 * Sample where the filesystem has been mounted and
+		 * store it in the superblock for sysadmin convenience
+		 * when trying to sort through large numbers of block
+		 * devices or filesystem images.
+		 */
+		memset(buf, 0, sizeof(buf));
+		path.mnt = mnt;
+		path.dentry = mnt->mnt_root;
+		cp = d_path(&path, buf, sizeof(buf));
+		if (!IS_ERR(cp)) {
+			handle_t *handle;
+			int err;
+
+			handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
+			if (IS_ERR(handle))
+				return PTR_ERR(handle);
+			BUFFER_TRACE(sbi->s_sbh, "get_write_access");
+			err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+			if (err) {
+				ext4_journal_stop(handle);
+				return err;
+			}
+			strlcpy(sbi->s_es->s_last_mounted, cp,
+				sizeof(sbi->s_es->s_last_mounted));
+			ext4_handle_dirty_super(handle, sb);
+			ext4_journal_stop(handle);
+		}
+	}
+	/*
+	 * Set up the jbd2_inode if we are opening the inode for
+	 * writing and the journal is present
+	 */
+	if (filp->f_mode & FMODE_WRITE) {
+		int ret = ext4_inode_attach_jinode(inode);
+		if (ret < 0)
+			return ret;
+	}
+	return dquot_file_open(inode, filp);
+}
+
+/*
+ * Here we use ext4_map_blocks() to get a block mapping for a extent-based
+ * file rather than ext4_ext_walk_space() because we can introduce
+ * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
+ * function.  When extent status tree has been fully implemented, it will
+ * track all extent status for a file and we can directly use it to
+ * retrieve the offset for SEEK_DATA/SEEK_HOLE.
+ */
+
+/*
+ * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
+ * lookup page cache to check whether or not there has some data between
+ * [startoff, endoff] because, if this range contains an unwritten extent,
+ * we determine this extent as a data or a hole according to whether the
+ * page cache has data or not.
+ */
+static int ext4_find_unwritten_pgoff(struct inode *inode,
+				     int whence,
+				     struct ext4_map_blocks *map,
+				     loff_t *offset)
+{
+	struct pagevec pvec;
+	unsigned int blkbits;
+	pgoff_t index;
+	pgoff_t end;
+	loff_t endoff;
+	loff_t startoff;
+	loff_t lastoff;
+	int found = 0;
+
+	blkbits = inode->i_sb->s_blocksize_bits;
+	startoff = *offset;
+	lastoff = startoff;
+	endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits;
+
+	index = startoff >> PAGE_CACHE_SHIFT;
+	end = endoff >> PAGE_CACHE_SHIFT;
+
+	pagevec_init(&pvec, 0);
+	do {
+		int i, num;
+		unsigned long nr_pages;
+
+		num = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
+		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
+					  (pgoff_t)num);
+		if (nr_pages == 0) {
+			if (whence == SEEK_DATA)
+				break;
+
+			BUG_ON(whence != SEEK_HOLE);
+			/*
+			 * If this is the first time to go into the loop and
+			 * offset is not beyond the end offset, it will be a
+			 * hole at this offset
+			 */
+			if (lastoff == startoff || lastoff < endoff)
+				found = 1;
+			break;
+		}
+
+		/*
+		 * If this is the first time to go into the loop and
+		 * offset is smaller than the first page offset, it will be a
+		 * hole at this offset.
+		 */
+		if (lastoff == startoff && whence == SEEK_HOLE &&
+		    lastoff < page_offset(pvec.pages[0])) {
+			found = 1;
+			break;
+		}
+
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+			struct buffer_head *bh, *head;
+
+			/*
+			 * If the current offset is not beyond the end of given
+			 * range, it will be a hole.
+			 */
+			if (lastoff < endoff && whence == SEEK_HOLE &&
+			    page->index > end) {
+				found = 1;
+				*offset = lastoff;
+				goto out;
+			}
+
+			lock_page(page);
+
+			if (unlikely(page->mapping != inode->i_mapping)) {
+				unlock_page(page);
+				continue;
+			}
+
+			if (!page_has_buffers(page)) {
+				unlock_page(page);
+				continue;
+			}
+
+			if (page_has_buffers(page)) {
+				lastoff = page_offset(page);
+				bh = head = page_buffers(page);
+				do {
+					if (buffer_uptodate(bh) ||
+					    buffer_unwritten(bh)) {
+						if (whence == SEEK_DATA)
+							found = 1;
+					} else {
+						if (whence == SEEK_HOLE)
+							found = 1;
+					}
+					if (found) {
+						*offset = max_t(loff_t,
+							startoff, lastoff);
+						unlock_page(page);
+						goto out;
+					}
+					lastoff += bh->b_size;
+					bh = bh->b_this_page;
+				} while (bh != head);
+			}
+
+			lastoff = page_offset(page) + PAGE_SIZE;
+			unlock_page(page);
+		}
+
+		/*
+		 * The no. of pages is less than our desired, that would be a
+		 * hole in there.
+		 */
+		if (nr_pages < num && whence == SEEK_HOLE) {
+			found = 1;
+			*offset = lastoff;
+			break;
+		}
+
+		index = pvec.pages[i - 1]->index + 1;
+		pagevec_release(&pvec);
+	} while (index <= end);
+
+out:
+	pagevec_release(&pvec);
+	return found;
+}
+
+/*
+ * ext4_seek_data() retrieves the offset for SEEK_DATA.
+ */
+static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct ext4_map_blocks map;
+	struct extent_status es;
+	ext4_lblk_t start, last, end;
+	loff_t dataoff, isize;
+	int blkbits;
+	int ret = 0;
+
+	mutex_lock(&inode->i_mutex);
+
+	isize = i_size_read(inode);
+	if (offset >= isize) {
+		mutex_unlock(&inode->i_mutex);
+		return -ENXIO;
+	}
+
+	blkbits = inode->i_sb->s_blocksize_bits;
+	start = offset >> blkbits;
+	last = start;
+	end = isize >> blkbits;
+	dataoff = offset;
+
+	do {
+		map.m_lblk = last;
+		map.m_len = end - last + 1;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
+			if (last != start)
+				dataoff = (loff_t)last << blkbits;
+			break;
+		}
+
+		/*
+		 * If there is a delay extent at this offset,
+		 * it will be as a data.
+		 */
+		ext4_es_find_delayed_extent_range(inode, last, last, &es);
+		if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
+			if (last != start)
+				dataoff = (loff_t)last << blkbits;
+			break;
+		}
+
+		/*
+		 * If there is a unwritten extent at this offset,
+		 * it will be as a data or a hole according to page
+		 * cache that has data or not.
+		 */
+		if (map.m_flags & EXT4_MAP_UNWRITTEN) {
+			int unwritten;
+			unwritten = ext4_find_unwritten_pgoff(inode, SEEK_DATA,
+							      &map, &dataoff);
+			if (unwritten)
+				break;
+		}
+
+		last++;
+		dataoff = (loff_t)last << blkbits;
+	} while (last <= end);
+
+	mutex_unlock(&inode->i_mutex);
+
+	if (dataoff > isize)
+		return -ENXIO;
+
+	return vfs_setpos(file, dataoff, maxsize);
+}
+
+/*
+ * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
+ */
+static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct ext4_map_blocks map;
+	struct extent_status es;
+	ext4_lblk_t start, last, end;
+	loff_t holeoff, isize;
+	int blkbits;
+	int ret = 0;
+
+	mutex_lock(&inode->i_mutex);
+
+	isize = i_size_read(inode);
+	if (offset >= isize) {
+		mutex_unlock(&inode->i_mutex);
+		return -ENXIO;
+	}
+
+	blkbits = inode->i_sb->s_blocksize_bits;
+	start = offset >> blkbits;
+	last = start;
+	end = isize >> blkbits;
+	holeoff = offset;
+
+	do {
+		map.m_lblk = last;
+		map.m_len = end - last + 1;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
+			last += ret;
+			holeoff = (loff_t)last << blkbits;
+			continue;
+		}
+
+		/*
+		 * If there is a delay extent at this offset,
+		 * we will skip this extent.
+		 */
+		ext4_es_find_delayed_extent_range(inode, last, last, &es);
+		if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
+			last = es.es_lblk + es.es_len;
+			holeoff = (loff_t)last << blkbits;
+			continue;
+		}
+
+		/*
+		 * If there is a unwritten extent at this offset,
+		 * it will be as a data or a hole according to page
+		 * cache that has data or not.
+		 */
+		if (map.m_flags & EXT4_MAP_UNWRITTEN) {
+			int unwritten;
+			unwritten = ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
+							      &map, &holeoff);
+			if (!unwritten) {
+				last += ret;
+				holeoff = (loff_t)last << blkbits;
+				continue;
+			}
+		}
+
+		/* find a hole */
+		break;
+	} while (last <= end);
+
+	mutex_unlock(&inode->i_mutex);
+
+	if (holeoff > isize)
+		holeoff = isize;
+
+	return vfs_setpos(file, holeoff, maxsize);
+}
+
+/*
+ * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
+ * by calling generic_file_llseek_size() with the appropriate maxbytes
+ * value for each.
+ */
+loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	loff_t maxbytes;
+
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
+	else
+		maxbytes = inode->i_sb->s_maxbytes;
+
+	switch (whence) {
+	case SEEK_SET:
+	case SEEK_CUR:
+	case SEEK_END:
+		return generic_file_llseek_size(file, offset, whence,
+						maxbytes, i_size_read(inode));
+	case SEEK_DATA:
+		return ext4_seek_data(file, offset, maxbytes);
+	case SEEK_HOLE:
+		return ext4_seek_hole(file, offset, maxbytes);
+	}
+
+	return -EINVAL;
+}
+
+const struct file_operations ext4_file_operations = {
+	.llseek		= ext4_llseek,
+	.read		= new_sync_read,
+	.write		= new_sync_write,
+	.read_iter	= generic_file_read_iter,
+	.write_iter	= ext4_file_write_iter,
+	.unlocked_ioctl = ext4_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext4_compat_ioctl,
+#endif
+	.mmap		= ext4_file_mmap,
+	.open		= ext4_file_open,
+	.release	= ext4_release_file,
+	.fsync		= ext4_sync_file,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= iter_file_splice_write,
+	.fallocate	= ext4_fallocate,
+};
+
+const struct inode_operations ext4_file_inode_operations = {
+	.setattr	= ext4_setattr,
+	.getattr	= ext4_getattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext4_listxattr,
+	.removexattr	= generic_removexattr,
+	.get_acl	= ext4_get_acl,
+	.set_acl	= ext4_set_acl,
+	.fiemap		= ext4_fiemap,
+};
+

fs/ext4/fsync.c

@@ -0,0 +1,151 @@
+/*
+ *  linux/fs/ext4/fsync.c
+ *
+ *  Copyright (C) 1993  Stephen Tweedie (sct@redhat.com)
+ *  from
+ *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
+ *                      Laboratoire MASI - Institut Blaise Pascal
+ *                      Universite Pierre et Marie Curie (Paris VI)
+ *  from
+ *  linux/fs/minix/truncate.c   Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4fs fsync primitive
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ *  Removed unnecessary code duplication for little endian machines
+ *  and excessive __inline__s.
+ *        Andi Kleen, 1997
+ *
+ * Major simplications and cleanup - we only need to do the metadata, because
+ * we can depend on generic_block_fdatasync() to sync the data blocks.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/writeback.h>
+#include <linux/jbd2.h>
+#include <linux/blkdev.h>
+
+#include "ext4.h"
+#include "ext4_jbd2.h"
+
+#include <trace/events/ext4.h>
+
+/*
+ * If we're not journaling and this is a just-created file, we have to
+ * sync our parent directory (if it was freshly created) since
+ * otherwise it will only be written by writeback, leaving a huge
+ * window during which a crash may lose the file.  This may apply for
+ * the parent directory's parent as well, and so on recursively, if
+ * they are also freshly created.
+ */
+static int ext4_sync_parent(struct inode *inode)
+{
+	struct dentry *dentry = NULL;
+	struct inode *next;
+	int ret = 0;
+
+	if (!ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY))
+		return 0;
+	inode = igrab(inode);
+	while (ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {
+		ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);
+		dentry = d_find_any_alias(inode);
+		if (!dentry)
+			break;
+		next = igrab(dentry->d_parent->d_inode);
+		dput(dentry);
+		if (!next)
+			break;
+		iput(inode);
+		inode = next;
+		ret = sync_mapping_buffers(inode->i_mapping);
+		if (ret)
+			break;
+		ret = sync_inode_metadata(inode, 1);
+		if (ret)
+			break;
+	}
+	iput(inode);
+	return ret;
+}
+
+/*
+ * akpm: A new design for ext4_sync_file().
+ *
+ * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
+ * There cannot be a transaction open by this task.
+ * Another task could have dirtied this inode.  Its data can be in any
+ * state in the journalling system.
+ *
+ * What we do is just kick off a commit and wait on it.  This will snapshot the
+ * inode to disk.
+ */
+
+int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
+	int ret = 0, err;
+	tid_t commit_tid;
+	bool needs_barrier = false;
+
+	J_ASSERT(ext4_journal_current_handle() == NULL);
+
+	trace_ext4_sync_file_enter(file, datasync);
+
+	if (inode->i_sb->s_flags & MS_RDONLY) {
+		/* Make sure that we read updated s_mount_flags value */
+		smp_rmb();
+		if (EXT4_SB(inode->i_sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
+			ret = -EROFS;
+		goto out;
+	}
+
+	if (!journal) {
+		ret = generic_file_fsync(file, start, end, datasync);
+		if (!ret && !hlist_empty(&inode->i_dentry))
+			ret = ext4_sync_parent(inode);
+		goto out;
+	}
+
+	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (ret)
+		return ret;
+	/*
+	 * data=writeback,ordered:
+	 *  The caller's filemap_fdatawrite()/wait will sync the data.
+	 *  Metadata is in the journal, we wait for proper transaction to
+	 *  commit here.
+	 *
+	 * data=journal:
+	 *  filemap_fdatawrite won't do anything (the buffers are clean).
+	 *  ext4_force_commit will write the file data into the journal and
+	 *  will wait on that.
+	 *  filemap_fdatawait() will encounter a ton of newly-dirtied pages
+	 *  (they were dirtied by commit).  But that's OK - the blocks are
+	 *  safe in-journal, which is all fsync() needs to ensure.
+	 */
+	if (ext4_should_journal_data(inode)) {
+		ret = ext4_force_commit(inode->i_sb);
+		goto out;
+	}
+
+	commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
+	if (journal->j_flags & JBD2_BARRIER &&
+	    !jbd2_trans_will_send_data_barrier(journal, commit_tid))
+		needs_barrier = true;
+	ret = jbd2_complete_transaction(journal, commit_tid);
+	if (needs_barrier) {
+		err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+		if (!ret)
+			ret = err;
+	}
+out:
+	trace_ext4_sync_file_exit(inode, ret);
+	return ret;
+}

fs/ext4/hash.c

@@ -0,0 +1,208 @@
+/*
+ *  linux/fs/ext4/hash.c
+ *
+ * Copyright (C) 2002 by Theodore Ts'o
+ *
+ * This file is released under the GPL v2.
+ *
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/cryptohash.h>
+#include "ext4.h"
+
+#define DELTA 0x9E3779B9
+
+static void TEA_transform(__u32 buf[4], __u32 const in[])
+{
+	__u32	sum = 0;
+	__u32	b0 = buf[0], b1 = buf[1];
+	__u32	a = in[0], b = in[1], c = in[2], d = in[3];
+	int	n = 16;
+
+	do {
+		sum += DELTA;
+		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
+		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
+	} while (--n);
+
+	buf[0] += b0;
+	buf[1] += b1;
+}
+
+
+/* The old legacy hash */
+static __u32 dx_hack_hash_unsigned(const char *name, int len)
+{
+	__u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+	const unsigned char *ucp = (const unsigned char *) name;
+
+	while (len--) {
+		hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));
+
+		if (hash & 0x80000000)
+			hash -= 0x7fffffff;
+		hash1 = hash0;
+		hash0 = hash;
+	}
+	return hash0 << 1;
+}
+
+static __u32 dx_hack_hash_signed(const char *name, int len)
+{
+	__u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+	const signed char *scp = (const signed char *) name;
+
+	while (len--) {
+		hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));
+
+		if (hash & 0x80000000)
+			hash -= 0x7fffffff;
+		hash1 = hash0;
+		hash0 = hash;
+	}
+	return hash0 << 1;
+}
+
+static void str2hashbuf_signed(const char *msg, int len, __u32 *buf, int num)
+{
+	__u32	pad, val;
+	int	i;
+	const signed char *scp = (const signed char *) msg;
+
+	pad = (__u32)len | ((__u32)len << 8);
+	pad |= pad << 16;
+
+	val = pad;
+	if (len > num*4)
+		len = num * 4;
+	for (i = 0; i < len; i++) {
+		if ((i % 4) == 0)
+			val = pad;
+		val = ((int) scp[i]) + (val << 8);
+		if ((i % 4) == 3) {
+			*buf++ = val;
+			val = pad;
+			num--;
+		}
+	}
+	if (--num >= 0)
+		*buf++ = val;
+	while (--num >= 0)
+		*buf++ = pad;
+}
+
+static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
+{
+	__u32	pad, val;
+	int	i;
+	const unsigned char *ucp = (const unsigned char *) msg;
+
+	pad = (__u32)len | ((__u32)len << 8);
+	pad |= pad << 16;
+
+	val = pad;
+	if (len > num*4)
+		len = num * 4;
+	for (i = 0; i < len; i++) {
+		if ((i % 4) == 0)
+			val = pad;
+		val = ((int) ucp[i]) + (val << 8);
+		if ((i % 4) == 3) {
+			*buf++ = val;
+			val = pad;
+			num--;
+		}
+	}
+	if (--num >= 0)
+		*buf++ = val;
+	while (--num >= 0)
+		*buf++ = pad;
+}
+
+/*
+ * Returns the hash of a filename.  If len is 0 and name is NULL, then
+ * this function can be used to test whether or not a hash version is
+ * supported.
+ *
+ * The seed is an 4 longword (32 bits) "secret" which can be used to
+ * uniquify a hash.  If the seed is all zero's, then some default seed
+ * may be used.
+ *
+ * A particular hash version specifies whether or not the seed is
+ * represented, and whether or not the returned hash is 32 bits or 64
+ * bits.  32 bit hashes will return 0 for the minor hash.
+ */
+int ext4fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
+{
+	__u32	hash;
+	__u32	minor_hash = 0;
+	const char	*p;
+	int		i;
+	__u32		in[8], buf[4];
+	void		(*str2hashbuf)(const char *, int, __u32 *, int) =
+				str2hashbuf_signed;
+
+	/* Initialize the default seed for the hash checksum functions */
+	buf[0] = 0x67452301;
+	buf[1] = 0xefcdab89;
+	buf[2] = 0x98badcfe;
+	buf[3] = 0x10325476;
+
+	/* Check to see if the seed is all zero's */
+	if (hinfo->seed) {
+		for (i = 0; i < 4; i++) {
+			if (hinfo->seed[i]) {
+				memcpy(buf, hinfo->seed, sizeof(buf));
+				break;
+			}
+		}
+	}
+
+	switch (hinfo->hash_version) {
+	case DX_HASH_LEGACY_UNSIGNED:
+		hash = dx_hack_hash_unsigned(name, len);
+		break;
+	case DX_HASH_LEGACY:
+		hash = dx_hack_hash_signed(name, len);
+		break;
+	case DX_HASH_HALF_MD4_UNSIGNED:
+		str2hashbuf = str2hashbuf_unsigned;
+	case DX_HASH_HALF_MD4:
+		p = name;
+		while (len > 0) {
+			(*str2hashbuf)(p, len, in, 8);
+			half_md4_transform(buf, in);
+			len -= 32;
+			p += 32;
+		}
+		minor_hash = buf[2];
+		hash = buf[1];
+		break;
+	case DX_HASH_TEA_UNSIGNED:
+		str2hashbuf = str2hashbuf_unsigned;
+	case DX_HASH_TEA:
+		p = name;
+		while (len > 0) {
+			(*str2hashbuf)(p, len, in, 4);
+			TEA_transform(buf, in);
+			len -= 16;
+			p += 16;
+		}
+		hash = buf[0];
+		minor_hash = buf[1];
+		break;
+	default:
+		hinfo->hash = 0;
+		return -1;
+	}
+	hash = hash & ~1;
+	if (hash == (EXT4_HTREE_EOF_32BIT << 1))
+		hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;
+	hinfo->hash = hash;
+	hinfo->minor_hash = minor_hash;
+	return 0;
+}

fs/ext4/ioctl.c

@@ -0,0 +1,700 @@
+/*
+ * linux/fs/ext4/ioctl.c
+ *
+ * Copyright (C) 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/capability.h>
+#include <linux/time.h>
+#include <linux/compat.h>
+#include <linux/mount.h>
+#include <linux/file.h>
+#include <asm/uaccess.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+
+#define MAX_32_NUM ((((unsigned long long) 1) << 32) - 1)
+
+/**
+ * Swap memory between @a and @b for @len bytes.
+ *
+ * @a:          pointer to first memory area
+ * @b:          pointer to second memory area
+ * @len:        number of bytes to swap
+ *
+ */
+static void memswap(void *a, void *b, size_t len)
+{
+	unsigned char *ap, *bp;
+	unsigned char tmp;
+
+	ap = (unsigned char *)a;
+	bp = (unsigned char *)b;
+	while (len-- > 0) {
+		tmp = *ap;
+		*ap = *bp;
+		*bp = tmp;
+		ap++;
+		bp++;
+	}
+}
+
+/**
+ * Swap i_data and associated attributes between @inode1 and @inode2.
+ * This function is used for the primary swap between inode1 and inode2
+ * and also to revert this primary swap in case of errors.
+ *
+ * Therefore you have to make sure, that calling this method twice
+ * will revert all changes.
+ *
+ * @inode1:     pointer to first inode
+ * @inode2:     pointer to second inode
+ */
+static void swap_inode_data(struct inode *inode1, struct inode *inode2)
+{
+	loff_t isize;
+	struct ext4_inode_info *ei1;
+	struct ext4_inode_info *ei2;
+
+	ei1 = EXT4_I(inode1);
+	ei2 = EXT4_I(inode2);
+
+	memswap(&inode1->i_flags, &inode2->i_flags, sizeof(inode1->i_flags));
+	memswap(&inode1->i_version, &inode2->i_version,
+		  sizeof(inode1->i_version));
+	memswap(&inode1->i_blocks, &inode2->i_blocks,
+		  sizeof(inode1->i_blocks));
+	memswap(&inode1->i_bytes, &inode2->i_bytes, sizeof(inode1->i_bytes));
+	memswap(&inode1->i_atime, &inode2->i_atime, sizeof(inode1->i_atime));
+	memswap(&inode1->i_mtime, &inode2->i_mtime, sizeof(inode1->i_mtime));
+
+	memswap(ei1->i_data, ei2->i_data, sizeof(ei1->i_data));
+	memswap(&ei1->i_flags, &ei2->i_flags, sizeof(ei1->i_flags));
+	memswap(&ei1->i_disksize, &ei2->i_disksize, sizeof(ei1->i_disksize));
+	ext4_es_remove_extent(inode1, 0, EXT_MAX_BLOCKS);
+	ext4_es_remove_extent(inode2, 0, EXT_MAX_BLOCKS);
+	ext4_es_lru_del(inode1);
+	ext4_es_lru_del(inode2);
+
+	isize = i_size_read(inode1);
+	i_size_write(inode1, i_size_read(inode2));
+	i_size_write(inode2, isize);
+}
+
+/**
+ * Swap the information from the given @inode and the inode
+ * EXT4_BOOT_LOADER_INO. It will basically swap i_data and all other
+ * important fields of the inodes.
+ *
+ * @sb:         the super block of the filesystem
+ * @inode:      the inode to swap with EXT4_BOOT_LOADER_INO
+ *
+ */
+static long swap_inode_boot_loader(struct super_block *sb,
+				struct inode *inode)
+{
+	handle_t *handle;
+	int err;
+	struct inode *inode_bl;
+	struct ext4_inode_info *ei_bl;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode))
+		return -EINVAL;
+
+	if (!inode_owner_or_capable(inode) || !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO);
+	if (IS_ERR(inode_bl))
+		return PTR_ERR(inode_bl);
+	ei_bl = EXT4_I(inode_bl);
+
+	filemap_flush(inode->i_mapping);
+	filemap_flush(inode_bl->i_mapping);
+
+	/* Protect orig inodes against a truncate and make sure,
+	 * that only 1 swap_inode_boot_loader is running. */
+	lock_two_nondirectories(inode, inode_bl);
+
+	truncate_inode_pages(&inode->i_data, 0);
+	truncate_inode_pages(&inode_bl->i_data, 0);
+
+	/* Wait for all existing dio workers */
+	ext4_inode_block_unlocked_dio(inode);
+	ext4_inode_block_unlocked_dio(inode_bl);
+	inode_dio_wait(inode);
+	inode_dio_wait(inode_bl);
+
+	handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2);
+	if (IS_ERR(handle)) {
+		err = -EINVAL;
+		goto journal_err_out;
+	}
+
+	/* Protect extent tree against block allocations via delalloc */
+	ext4_double_down_write_data_sem(inode, inode_bl);
+
+	if (inode_bl->i_nlink == 0) {
+		/* this inode has never been used as a BOOT_LOADER */
+		set_nlink(inode_bl, 1);
+		i_uid_write(inode_bl, 0);
+		i_gid_write(inode_bl, 0);
+		inode_bl->i_flags = 0;
+		ei_bl->i_flags = 0;
+		inode_bl->i_version = 1;
+		i_size_write(inode_bl, 0);
+		inode_bl->i_mode = S_IFREG;
+		if (EXT4_HAS_INCOMPAT_FEATURE(sb,
+					      EXT4_FEATURE_INCOMPAT_EXTENTS)) {
+			ext4_set_inode_flag(inode_bl, EXT4_INODE_EXTENTS);
+			ext4_ext_tree_init(handle, inode_bl);
+		} else
+			memset(ei_bl->i_data, 0, sizeof(ei_bl->i_data));
+	}
+
+	swap_inode_data(inode, inode_bl);
+
+	inode->i_ctime = inode_bl->i_ctime = ext4_current_time(inode);
+
+	spin_lock(&sbi->s_next_gen_lock);
+	inode->i_generation = sbi->s_next_generation++;
+	inode_bl->i_generation = sbi->s_next_generation++;
+	spin_unlock(&sbi->s_next_gen_lock);
+
+	ext4_discard_preallocations(inode);
+
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (err < 0) {
+		ext4_warning(inode->i_sb,
+			"couldn't mark inode #%lu dirty (err %d)",
+			inode->i_ino, err);
+		/* Revert all changes: */
+		swap_inode_data(inode, inode_bl);
+	} else {
+		err = ext4_mark_inode_dirty(handle, inode_bl);
+		if (err < 0) {
+			ext4_warning(inode_bl->i_sb,
+				"couldn't mark inode #%lu dirty (err %d)",
+				inode_bl->i_ino, err);
+			/* Revert all changes: */
+			swap_inode_data(inode, inode_bl);
+			ext4_mark_inode_dirty(handle, inode);
+		}
+	}
+	ext4_journal_stop(handle);
+	ext4_double_up_write_data_sem(inode, inode_bl);
+
+journal_err_out:
+	ext4_inode_resume_unlocked_dio(inode);
+	ext4_inode_resume_unlocked_dio(inode_bl);
+	unlock_two_nondirectories(inode, inode_bl);
+	iput(inode_bl);
+	return err;
+}
+
+long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	struct super_block *sb = inode->i_sb;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	unsigned int flags;
+
+	ext4_debug("cmd = %u, arg = %lu\n", cmd, arg);
+
+	switch (cmd) {
+	case EXT4_IOC_GETFLAGS:
+		ext4_get_inode_flags(ei);
+		flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
+		return put_user(flags, (int __user *) arg);
+	case EXT4_IOC_SETFLAGS: {
+		handle_t *handle = NULL;
+		int err, migrate = 0;
+		struct ext4_iloc iloc;
+		unsigned int oldflags, mask, i;
+		unsigned int jflag;
+
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+
+		if (get_user(flags, (int __user *) arg))
+			return -EFAULT;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+
+		flags = ext4_mask_flags(inode->i_mode, flags);
+
+		err = -EPERM;
+		mutex_lock(&inode->i_mutex);
+		/* Is it quota file? Do not allow user to mess with it */
+		if (IS_NOQUOTA(inode))
+			goto flags_out;
+
+		oldflags = ei->i_flags;
+
+		/* The JOURNAL_DATA flag is modifiable only by root */
+		jflag = flags & EXT4_JOURNAL_DATA_FL;
+
+		/*
+		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
+		 * the relevant capability.
+		 *
+		 * This test looks nicer. Thanks to Pauline Middelink
+		 */
+		if ((flags ^ oldflags) & (EXT4_APPEND_FL | EXT4_IMMUTABLE_FL)) {
+			if (!capable(CAP_LINUX_IMMUTABLE))
+				goto flags_out;
+		}
+
+		/*
+		 * The JOURNAL_DATA flag can only be changed by
+		 * the relevant capability.
+		 */
+		if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) {
+			if (!capable(CAP_SYS_RESOURCE))
+				goto flags_out;
+		}
+		if ((flags ^ oldflags) & EXT4_EXTENTS_FL)
+			migrate = 1;
+
+		if (flags & EXT4_EOFBLOCKS_FL) {
+			/* we don't support adding EOFBLOCKS flag */
+			if (!(oldflags & EXT4_EOFBLOCKS_FL)) {
+				err = -EOPNOTSUPP;
+				goto flags_out;
+			}
+		} else if (oldflags & EXT4_EOFBLOCKS_FL)
+			ext4_truncate(inode);
+
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+		if (IS_ERR(handle)) {
+			err = PTR_ERR(handle);
+			goto flags_out;
+		}
+		if (IS_SYNC(inode))
+			ext4_handle_sync(handle);
+		err = ext4_reserve_inode_write(handle, inode, &iloc);
+		if (err)
+			goto flags_err;
+
+		for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
+			if (!(mask & EXT4_FL_USER_MODIFIABLE))
+				continue;
+			if (mask & flags)
+				ext4_set_inode_flag(inode, i);
+			else
+				ext4_clear_inode_flag(inode, i);
+		}
+
+		ext4_set_inode_flags(inode);
+		inode->i_ctime = ext4_current_time(inode);
+
+		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+flags_err:
+		ext4_journal_stop(handle);
+		if (err)
+			goto flags_out;
+
+		if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL))
+			err = ext4_change_inode_journal_flag(inode, jflag);
+		if (err)
+			goto flags_out;
+		if (migrate) {
+			if (flags & EXT4_EXTENTS_FL)
+				err = ext4_ext_migrate(inode);
+			else
+				err = ext4_ind_migrate(inode);
+		}
+
+flags_out:
+		mutex_unlock(&inode->i_mutex);
+		mnt_drop_write_file(filp);
+		return err;
+	}
+	case EXT4_IOC_GETVERSION:
+	case EXT4_IOC_GETVERSION_OLD:
+		return put_user(inode->i_generation, (int __user *) arg);
+	case EXT4_IOC_SETVERSION:
+	case EXT4_IOC_SETVERSION_OLD: {
+		handle_t *handle;
+		struct ext4_iloc iloc;
+		__u32 generation;
+		int err;
+
+		if (!inode_owner_or_capable(inode))
+			return -EPERM;
+
+		if (ext4_has_metadata_csum(inode->i_sb)) {
+			ext4_warning(sb, "Setting inode version is not "
+				     "supported with metadata_csum enabled.");
+			return -ENOTTY;
+		}
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		if (get_user(generation, (int __user *) arg)) {
+			err = -EFAULT;
+			goto setversion_out;
+		}
+
+		mutex_lock(&inode->i_mutex);
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+		if (IS_ERR(handle)) {
+			err = PTR_ERR(handle);
+			goto unlock_out;
+		}
+		err = ext4_reserve_inode_write(handle, inode, &iloc);
+		if (err == 0) {
+			inode->i_ctime = ext4_current_time(inode);
+			inode->i_generation = generation;
+			err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+		}
+		ext4_journal_stop(handle);
+
+unlock_out:
+		mutex_unlock(&inode->i_mutex);
+setversion_out:
+		mnt_drop_write_file(filp);
+		return err;
+	}
+	case EXT4_IOC_GROUP_EXTEND: {
+		ext4_fsblk_t n_blocks_count;
+		int err, err2=0;
+
+		err = ext4_resize_begin(sb);
+		if (err)
+			return err;
+
+		if (get_user(n_blocks_count, (__u32 __user *)arg)) {
+			err = -EFAULT;
+			goto group_extend_out;
+		}
+
+		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online resizing not supported with bigalloc");
+			err = -EOPNOTSUPP;
+			goto group_extend_out;
+		}
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			goto group_extend_out;
+
+		err = ext4_group_extend(sb, EXT4_SB(sb)->s_es, n_blocks_count);
+		if (EXT4_SB(sb)->s_journal) {
+			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
+			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
+			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+		}
+		if (err == 0)
+			err = err2;
+		mnt_drop_write_file(filp);
+group_extend_out:
+		ext4_resize_end(sb);
+		return err;
+	}
+
+	case EXT4_IOC_MOVE_EXT: {
+		struct move_extent me;
+		struct fd donor;
+		int err;
+
+		if (!(filp->f_mode & FMODE_READ) ||
+		    !(filp->f_mode & FMODE_WRITE))
+			return -EBADF;
+
+		if (copy_from_user(&me,
+			(struct move_extent __user *)arg, sizeof(me)))
+			return -EFAULT;
+		me.moved_len = 0;
+
+		donor = fdget(me.donor_fd);
+		if (!donor.file)
+			return -EBADF;
+
+		if (!(donor.file->f_mode & FMODE_WRITE)) {
+			err = -EBADF;
+			goto mext_out;
+		}
+
+		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online defrag not supported with bigalloc");
+			err = -EOPNOTSUPP;
+			goto mext_out;
+		}
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			goto mext_out;
+
+		err = ext4_move_extents(filp, donor.file, me.orig_start,
+					me.donor_start, me.len, &me.moved_len);
+		mnt_drop_write_file(filp);
+
+		if (copy_to_user((struct move_extent __user *)arg,
+				 &me, sizeof(me)))
+			err = -EFAULT;
+mext_out:
+		fdput(donor);
+		return err;
+	}
+
+	case EXT4_IOC_GROUP_ADD: {
+		struct ext4_new_group_data input;
+		int err, err2=0;
+
+		err = ext4_resize_begin(sb);
+		if (err)
+			return err;
+
+		if (copy_from_user(&input, (struct ext4_new_group_input __user *)arg,
+				sizeof(input))) {
+			err = -EFAULT;
+			goto group_add_out;
+		}
+
+		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online resizing not supported with bigalloc");
+			err = -EOPNOTSUPP;
+			goto group_add_out;
+		}
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			goto group_add_out;
+
+		err = ext4_group_add(sb, &input);
+		if (EXT4_SB(sb)->s_journal) {
+			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
+			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
+			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+		}
+		if (err == 0)
+			err = err2;
+		mnt_drop_write_file(filp);
+		if (!err && ext4_has_group_desc_csum(sb) &&
+		    test_opt(sb, INIT_INODE_TABLE))
+			err = ext4_register_li_request(sb, input.group);
+group_add_out:
+		ext4_resize_end(sb);
+		return err;
+	}
+
+	case EXT4_IOC_MIGRATE:
+	{
+		int err;
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		/*
+		 * inode_mutex prevent write and truncate on the file.
+		 * Read still goes through. We take i_data_sem in
+		 * ext4_ext_swap_inode_data before we switch the
+		 * inode format to prevent read.
+		 */
+		mutex_lock(&(inode->i_mutex));
+		err = ext4_ext_migrate(inode);
+		mutex_unlock(&(inode->i_mutex));
+		mnt_drop_write_file(filp);
+		return err;
+	}
+
+	case EXT4_IOC_ALLOC_DA_BLKS:
+	{
+		int err;
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		err = ext4_alloc_da_blocks(inode);
+		mnt_drop_write_file(filp);
+		return err;
+	}
+
+	case EXT4_IOC_SWAP_BOOT:
+	{
+		int err;
+		if (!(filp->f_mode & FMODE_WRITE))
+			return -EBADF;
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		err = swap_inode_boot_loader(sb, inode);
+		mnt_drop_write_file(filp);
+		return err;
+	}
+
+	case EXT4_IOC_RESIZE_FS: {
+		ext4_fsblk_t n_blocks_count;
+		int err = 0, err2 = 0;
+		ext4_group_t o_group = EXT4_SB(sb)->s_groups_count;
+
+		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online resizing not (yet) supported with bigalloc");
+			return -EOPNOTSUPP;
+		}
+
+		if (copy_from_user(&n_blocks_count, (__u64 __user *)arg,
+				   sizeof(__u64))) {
+			return -EFAULT;
+		}
+
+		err = ext4_resize_begin(sb);
+		if (err)
+			return err;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			goto resizefs_out;
+
+		err = ext4_resize_fs(sb, n_blocks_count);
+		if (EXT4_SB(sb)->s_journal) {
+			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
+			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
+			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+		}
+		if (err == 0)
+			err = err2;
+		mnt_drop_write_file(filp);
+		if (!err && (o_group > EXT4_SB(sb)->s_groups_count) &&
+		    ext4_has_group_desc_csum(sb) &&
+		    test_opt(sb, INIT_INODE_TABLE))
+			err = ext4_register_li_request(sb, o_group);
+
+resizefs_out:
+		ext4_resize_end(sb);
+		return err;
+	}
+
+	case FIDTRIM:
+	case FITRIM:
+	{
+		struct request_queue *q = bdev_get_queue(sb->s_bdev);
+		struct fstrim_range range;
+		int ret = 0;
+		int flags  = cmd == FIDTRIM ? BLKDEV_DISCARD_SECURE : 0;
+
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		if (!blk_queue_discard(q))
+			return -EOPNOTSUPP;
+
+		if ((flags & BLKDEV_DISCARD_SECURE) && !blk_queue_secdiscard(q))
+			return -EOPNOTSUPP;
+		if (copy_from_user(&range, (struct fstrim_range __user *)arg,
+		    sizeof(range)))
+			return -EFAULT;
+
+		range.minlen = max((unsigned int)range.minlen,
+				   q->limits.discard_granularity);
+		ret = ext4_trim_fs(sb, &range, flags);
+		if (ret < 0)
+			return ret;
+
+		if (copy_to_user((struct fstrim_range __user *)arg, &range,
+		    sizeof(range)))
+			return -EFAULT;
+
+		return 0;
+	}
+	case EXT4_IOC_PRECACHE_EXTENTS:
+		return ext4_ext_precache(inode);
+
+	case FS_IOC_INVAL_MAPPING:
+	{
+		return invalidate_mapping_pages(inode->i_mapping, 0, -1);
+	}
+
+	default:
+		return -ENOTTY;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	/* These are just misnamed, they actually get/put from/to user an int */
+	switch (cmd) {
+	case EXT4_IOC32_GETFLAGS:
+		cmd = EXT4_IOC_GETFLAGS;
+		break;
+	case EXT4_IOC32_SETFLAGS:
+		cmd = EXT4_IOC_SETFLAGS;
+		break;
+	case EXT4_IOC32_GETVERSION:
+		cmd = EXT4_IOC_GETVERSION;
+		break;
+	case EXT4_IOC32_SETVERSION:
+		cmd = EXT4_IOC_SETVERSION;
+		break;
+	case EXT4_IOC32_GROUP_EXTEND:
+		cmd = EXT4_IOC_GROUP_EXTEND;
+		break;
+	case EXT4_IOC32_GETVERSION_OLD:
+		cmd = EXT4_IOC_GETVERSION_OLD;
+		break;
+	case EXT4_IOC32_SETVERSION_OLD:
+		cmd = EXT4_IOC_SETVERSION_OLD;
+		break;
+	case EXT4_IOC32_GETRSVSZ:
+		cmd = EXT4_IOC_GETRSVSZ;
+		break;
+	case EXT4_IOC32_SETRSVSZ:
+		cmd = EXT4_IOC_SETRSVSZ;
+		break;
+	case EXT4_IOC32_GROUP_ADD: {
+		struct compat_ext4_new_group_input __user *uinput;
+		struct ext4_new_group_input input;
+		mm_segment_t old_fs;
+		int err;
+
+		uinput = compat_ptr(arg);
+		err = get_user(input.group, &uinput->group);
+		err |= get_user(input.block_bitmap, &uinput->block_bitmap);
+		err |= get_user(input.inode_bitmap, &uinput->inode_bitmap);
+		err |= get_user(input.inode_table, &uinput->inode_table);
+		err |= get_user(input.blocks_count, &uinput->blocks_count);
+		err |= get_user(input.reserved_blocks,
+				&uinput->reserved_blocks);
+		if (err)
+			return -EFAULT;
+		old_fs = get_fs();
+		set_fs(KERNEL_DS);
+		err = ext4_ioctl(file, EXT4_IOC_GROUP_ADD,
+				 (unsigned long) &input);
+		set_fs(old_fs);
+		return err;
+	}
+	case EXT4_IOC_MOVE_EXT:
+	case FITRIM:
+	case EXT4_IOC_RESIZE_FS:
+	case EXT4_IOC_PRECACHE_EXTENTS:
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+	return ext4_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
+}
+#endif

fs/ext4/mballoc.h

@@ -0,0 +1,215 @@
+/*
+ *  fs/ext4/mballoc.h
+ *
+ *  Written by: Alex Tomas <alex@clusterfs.com>
+ *
+ */
+#ifndef _EXT4_MBALLOC_H
+#define _EXT4_MBALLOC_H
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include <linux/module.h>
+#include <linux/swap.h>
+#include <linux/proc_fs.h>
+#include <linux/pagemap.h>
+#include <linux/seq_file.h>
+#include <linux/blkdev.h>
+#include <linux/mutex.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+
+/*
+ * with AGGRESSIVE_CHECK allocator runs consistency checks over
+ * structures. these checks slow things down a lot
+ */
+#define AGGRESSIVE_CHECK__
+
+/*
+ * with DOUBLE_CHECK defined mballoc creates persistent in-core
+ * bitmaps, maintains and uses them to check for double allocations
+ */
+#define DOUBLE_CHECK__
+
+/*
+ */
+#ifdef CONFIG_EXT4_DEBUG
+extern ushort ext4_mballoc_debug;
+
+#define mb_debug(n, fmt, a...)	                                        \
+	do {								\
+		if ((n) <= ext4_mballoc_debug) {		        \
+			printk(KERN_DEBUG "(%s, %d): %s: ",		\
+			       __FILE__, __LINE__, __func__);		\
+			printk(fmt, ## a);				\
+		}							\
+	} while (0)
+#else
+#define mb_debug(n, fmt, a...)		no_printk(fmt, ## a)
+#endif
+
+#define EXT4_MB_HISTORY_ALLOC		1	/* allocation */
+#define EXT4_MB_HISTORY_PREALLOC	2	/* preallocated blocks used */
+
+/*
+ * How long mballoc can look for a best extent (in found extents)
+ */
+#define MB_DEFAULT_MAX_TO_SCAN		200
+
+/*
+ * How long mballoc must look for a best extent
+ */
+#define MB_DEFAULT_MIN_TO_SCAN		10
+
+/*
+ * with 'ext4_mb_stats' allocator will collect stats that will be
+ * shown at umount. The collecting costs though!
+ */
+#define MB_DEFAULT_STATS		0
+
+/*
+ * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
+ * by the stream allocator, which purpose is to pack requests
+ * as close each to other as possible to produce smooth I/O traffic
+ * We use locality group prealloc space for stream request.
+ * We can tune the same via /proc/fs/ext4/<parition>/stream_req
+ */
+#define MB_DEFAULT_STREAM_THRESHOLD	16	/* 64K */
+
+/*
+ * for which requests use 2^N search using buddies
+ */
+#define MB_DEFAULT_ORDER2_REQS		2
+
+/*
+ * default group prealloc size 512 blocks
+ */
+#define MB_DEFAULT_GROUP_PREALLOC	512
+
+
+struct ext4_free_data {
+	/* MUST be the first member */
+	struct ext4_journal_cb_entry	efd_jce;
+
+	/* ext4_free_data private data starts from here */
+
+	/* this links the free block information from group_info */
+	struct rb_node			efd_node;
+
+	/* group which free block extent belongs */
+	ext4_group_t			efd_group;
+
+	/* free block extent */
+	ext4_grpblk_t			efd_start_cluster;
+	ext4_grpblk_t			efd_count;
+
+	/* transaction which freed this extent */
+	tid_t				efd_tid;
+};
+
+struct ext4_prealloc_space {
+	struct list_head	pa_inode_list;
+	struct list_head	pa_group_list;
+	union {
+		struct list_head pa_tmp_list;
+		struct rcu_head	pa_rcu;
+	} u;
+	spinlock_t		pa_lock;
+	atomic_t		pa_count;
+	unsigned		pa_deleted;
+	ext4_fsblk_t		pa_pstart;	/* phys. block */
+	ext4_lblk_t		pa_lstart;	/* log. block */
+	ext4_grpblk_t		pa_len;		/* len of preallocated chunk */
+	ext4_grpblk_t		pa_free;	/* how many blocks are free */
+	unsigned short		pa_type;	/* pa type. inode or group */
+	spinlock_t		*pa_obj_lock;
+	struct inode		*pa_inode;	/* hack, for history only */
+};
+
+enum {
+	MB_INODE_PA = 0,
+	MB_GROUP_PA = 1
+};
+
+struct ext4_free_extent {
+	ext4_lblk_t fe_logical;
+	ext4_grpblk_t fe_start;	/* In cluster units */
+	ext4_group_t fe_group;
+	ext4_grpblk_t fe_len;	/* In cluster units */
+};
+
+/*
+ * Locality group:
+ *   we try to group all related changes together
+ *   so that writeback can flush/allocate them together as well
+ *   Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
+ *   (512). We store prealloc space into the hash based on the pa_free blocks
+ *   order value.ie, fls(pa_free)-1;
+ */
+#define PREALLOC_TB_SIZE 10
+struct ext4_locality_group {
+	/* for allocator */
+	/* to serialize allocates */
+	struct mutex		lg_mutex;
+	/* list of preallocations */
+	struct list_head	lg_prealloc_list[PREALLOC_TB_SIZE];
+	spinlock_t		lg_prealloc_lock;
+};
+
+struct ext4_allocation_context {
+	struct inode *ac_inode;
+	struct super_block *ac_sb;
+
+	/* original request */
+	struct ext4_free_extent ac_o_ex;
+
+	/* goal request (normalized ac_o_ex) */
+	struct ext4_free_extent ac_g_ex;
+
+	/* the best found extent */
+	struct ext4_free_extent ac_b_ex;
+
+	/* copy of the best found extent taken before preallocation efforts */
+	struct ext4_free_extent ac_f_ex;
+
+	__u16 ac_groups_scanned;
+	__u16 ac_found;
+	__u16 ac_tail;
+	__u16 ac_buddy;
+	__u16 ac_flags;		/* allocation hints */
+	__u8 ac_status;
+	__u8 ac_criteria;
+	__u8 ac_2order;		/* if request is to allocate 2^N blocks and
+				 * N > 0, the field stores N, otherwise 0 */
+	__u8 ac_op;		/* operation, for history only */
+	struct page *ac_bitmap_page;
+	struct page *ac_buddy_page;
+	struct ext4_prealloc_space *ac_pa;
+	struct ext4_locality_group *ac_lg;
+};
+
+#define AC_STATUS_CONTINUE	1
+#define AC_STATUS_FOUND		2
+#define AC_STATUS_BREAK		3
+
+struct ext4_buddy {
+	struct page *bd_buddy_page;
+	void *bd_buddy;
+	struct page *bd_bitmap_page;
+	void *bd_bitmap;
+	struct ext4_group_info *bd_info;
+	struct super_block *bd_sb;
+	__u16 bd_blkbits;
+	ext4_group_t bd_group;
+};
+
+static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
+					struct ext4_free_extent *fex)
+{
+	return ext4_group_first_block_no(sb, fex->fe_group) +
+		(fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
+}
+#endif

fs/ext4/migrate.c

@@ -0,0 +1,672 @@
+/*
+ * Copyright IBM Corporation, 2007
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <linux/slab.h>
+#include "ext4_jbd2.h"
+#include "ext4_extents.h"
+
+/*
+ * The contiguous blocks details which can be
+ * represented by a single extent
+ */
+struct migrate_struct {
+	ext4_lblk_t first_block, last_block, curr_block;
+	ext4_fsblk_t first_pblock, last_pblock;
+};
+
+static int finish_range(handle_t *handle, struct inode *inode,
+				struct migrate_struct *lb)
+
+{
+	int retval = 0, needed;
+	struct ext4_extent newext;
+	struct ext4_ext_path *path;
+	if (lb->first_pblock == 0)
+		return 0;
+
+	/* Add the extent to temp inode*/
+	newext.ee_block = cpu_to_le32(lb->first_block);
+	newext.ee_len   = cpu_to_le16(lb->last_block - lb->first_block + 1);
+	ext4_ext_store_pblock(&newext, lb->first_pblock);
+	/* Locking only for convinience since we are operating on temp inode */
+	down_write(&EXT4_I(inode)->i_data_sem);
+	path = ext4_find_extent(inode, lb->first_block, NULL, 0);
+	if (IS_ERR(path)) {
+		retval = PTR_ERR(path);
+		path = NULL;
+		goto err_out;
+	}
+
+	/*
+	 * Calculate the credit needed to inserting this extent
+	 * Since we are doing this in loop we may accumalate extra
+	 * credit. But below we try to not accumalate too much
+	 * of them by restarting the journal.
+	 */
+	needed = ext4_ext_calc_credits_for_single_extent(inode,
+		    lb->last_block - lb->first_block + 1, path);
+
+	/*
+	 * Make sure the credit we accumalated is not really high
+	 */
+	if (needed && ext4_handle_has_enough_credits(handle,
+						EXT4_RESERVE_TRANS_BLOCKS)) {
+		up_write((&EXT4_I(inode)->i_data_sem));
+		retval = ext4_journal_restart(handle, needed);
+		down_write((&EXT4_I(inode)->i_data_sem));
+		if (retval)
+			goto err_out;
+	} else if (needed) {
+		retval = ext4_journal_extend(handle, needed);
+		if (retval) {
+			/*
+			 * IF not able to extend the journal restart the journal
+			 */
+			up_write((&EXT4_I(inode)->i_data_sem));
+			retval = ext4_journal_restart(handle, needed);
+			down_write((&EXT4_I(inode)->i_data_sem));
+			if (retval)
+				goto err_out;
+		}
+	}
+	retval = ext4_ext_insert_extent(handle, inode, &path, &newext, 0);
+err_out:
+	up_write((&EXT4_I(inode)->i_data_sem));
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	lb->first_pblock = 0;
+	return retval;
+}
+
+static int update_extent_range(handle_t *handle, struct inode *inode,
+			       ext4_fsblk_t pblock, struct migrate_struct *lb)
+{
+	int retval;
+	/*
+	 * See if we can add on to the existing range (if it exists)
+	 */
+	if (lb->first_pblock &&
+		(lb->last_pblock+1 == pblock) &&
+		(lb->last_block+1 == lb->curr_block)) {
+		lb->last_pblock = pblock;
+		lb->last_block = lb->curr_block;
+		lb->curr_block++;
+		return 0;
+	}
+	/*
+	 * Start a new range.
+	 */
+	retval = finish_range(handle, inode, lb);
+	lb->first_pblock = lb->last_pblock = pblock;
+	lb->first_block = lb->last_block = lb->curr_block;
+	lb->curr_block++;
+	return retval;
+}
+
+static int update_ind_extent_range(handle_t *handle, struct inode *inode,
+				   ext4_fsblk_t pblock,
+				   struct migrate_struct *lb)
+{
+	struct buffer_head *bh;
+	__le32 *i_data;
+	int i, retval = 0;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = sb_bread(inode->i_sb, pblock);
+	if (!bh)
+		return -EIO;
+
+	i_data = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (i_data[i]) {
+			retval = update_extent_range(handle, inode,
+						le32_to_cpu(i_data[i]), lb);
+			if (retval)
+				break;
+		} else {
+			lb->curr_block++;
+		}
+	}
+	put_bh(bh);
+	return retval;
+
+}
+
+static int update_dind_extent_range(handle_t *handle, struct inode *inode,
+				    ext4_fsblk_t pblock,
+				    struct migrate_struct *lb)
+{
+	struct buffer_head *bh;
+	__le32 *i_data;
+	int i, retval = 0;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = sb_bread(inode->i_sb, pblock);
+	if (!bh)
+		return -EIO;
+
+	i_data = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (i_data[i]) {
+			retval = update_ind_extent_range(handle, inode,
+						le32_to_cpu(i_data[i]), lb);
+			if (retval)
+				break;
+		} else {
+			/* Only update the file block number */
+			lb->curr_block += max_entries;
+		}
+	}
+	put_bh(bh);
+	return retval;
+
+}
+
+static int update_tind_extent_range(handle_t *handle, struct inode *inode,
+				    ext4_fsblk_t pblock,
+				    struct migrate_struct *lb)
+{
+	struct buffer_head *bh;
+	__le32 *i_data;
+	int i, retval = 0;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = sb_bread(inode->i_sb, pblock);
+	if (!bh)
+		return -EIO;
+
+	i_data = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (i_data[i]) {
+			retval = update_dind_extent_range(handle, inode,
+						le32_to_cpu(i_data[i]), lb);
+			if (retval)
+				break;
+		} else {
+			/* Only update the file block number */
+			lb->curr_block += max_entries * max_entries;
+		}
+	}
+	put_bh(bh);
+	return retval;
+
+}
+
+static int extend_credit_for_blkdel(handle_t *handle, struct inode *inode)
+{
+	int retval = 0, needed;
+
+	if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
+		return 0;
+	/*
+	 * We are freeing a blocks. During this we touch
+	 * superblock, group descriptor and block bitmap.
+	 * So allocate a credit of 3. We may update
+	 * quota (user and group).
+	 */
+	needed = 3 + EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
+
+	if (ext4_journal_extend(handle, needed) != 0)
+		retval = ext4_journal_restart(handle, needed);
+
+	return retval;
+}
+
+static int free_dind_blocks(handle_t *handle,
+				struct inode *inode, __le32 i_data)
+{
+	int i;
+	__le32 *tmp_idata;
+	struct buffer_head *bh;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
+	if (!bh)
+		return -EIO;
+
+	tmp_idata = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (tmp_idata[i]) {
+			extend_credit_for_blkdel(handle, inode);
+			ext4_free_blocks(handle, inode, NULL,
+					 le32_to_cpu(tmp_idata[i]), 1,
+					 EXT4_FREE_BLOCKS_METADATA |
+					 EXT4_FREE_BLOCKS_FORGET);
+		}
+	}
+	put_bh(bh);
+	extend_credit_for_blkdel(handle, inode);
+	ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
+			 EXT4_FREE_BLOCKS_METADATA |
+			 EXT4_FREE_BLOCKS_FORGET);
+	return 0;
+}
+
+static int free_tind_blocks(handle_t *handle,
+				struct inode *inode, __le32 i_data)
+{
+	int i, retval = 0;
+	__le32 *tmp_idata;
+	struct buffer_head *bh;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
+	if (!bh)
+		return -EIO;
+
+	tmp_idata = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (tmp_idata[i]) {
+			retval = free_dind_blocks(handle,
+					inode, tmp_idata[i]);
+			if (retval) {
+				put_bh(bh);
+				return retval;
+			}
+		}
+	}
+	put_bh(bh);
+	extend_credit_for_blkdel(handle, inode);
+	ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
+			 EXT4_FREE_BLOCKS_METADATA |
+			 EXT4_FREE_BLOCKS_FORGET);
+	return 0;
+}
+
+static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
+{
+	int retval;
+
+	/* ei->i_data[EXT4_IND_BLOCK] */
+	if (i_data[0]) {
+		extend_credit_for_blkdel(handle, inode);
+		ext4_free_blocks(handle, inode, NULL,
+				le32_to_cpu(i_data[0]), 1,
+				 EXT4_FREE_BLOCKS_METADATA |
+				 EXT4_FREE_BLOCKS_FORGET);
+	}
+
+	/* ei->i_data[EXT4_DIND_BLOCK] */
+	if (i_data[1]) {
+		retval = free_dind_blocks(handle, inode, i_data[1]);
+		if (retval)
+			return retval;
+	}
+
+	/* ei->i_data[EXT4_TIND_BLOCK] */
+	if (i_data[2]) {
+		retval = free_tind_blocks(handle, inode, i_data[2]);
+		if (retval)
+			return retval;
+	}
+	return 0;
+}
+
+static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
+						struct inode *tmp_inode)
+{
+	int retval;
+	__le32	i_data[3];
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
+
+	/*
+	 * One credit accounted for writing the
+	 * i_data field of the original inode
+	 */
+	retval = ext4_journal_extend(handle, 1);
+	if (retval) {
+		retval = ext4_journal_restart(handle, 1);
+		if (retval)
+			goto err_out;
+	}
+
+	i_data[0] = ei->i_data[EXT4_IND_BLOCK];
+	i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
+	i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+	/*
+	 * if EXT4_STATE_EXT_MIGRATE is cleared a block allocation
+	 * happened after we started the migrate. We need to
+	 * fail the migrate
+	 */
+	if (!ext4_test_inode_state(inode, EXT4_STATE_EXT_MIGRATE)) {
+		retval = -EAGAIN;
+		up_write(&EXT4_I(inode)->i_data_sem);
+		goto err_out;
+	} else
+		ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
+	/*
+	 * We have the extent map build with the tmp inode.
+	 * Now copy the i_data across
+	 */
+	ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
+	memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
+
+	/*
+	 * Update i_blocks with the new blocks that got
+	 * allocated while adding extents for extent index
+	 * blocks.
+	 *
+	 * While converting to extents we need not
+	 * update the orignal inode i_blocks for extent blocks
+	 * via quota APIs. The quota update happened via tmp_inode already.
+	 */
+	spin_lock(&inode->i_lock);
+	inode->i_blocks += tmp_inode->i_blocks;
+	spin_unlock(&inode->i_lock);
+	up_write(&EXT4_I(inode)->i_data_sem);
+
+	/*
+	 * We mark the inode dirty after, because we decrement the
+	 * i_blocks when freeing the indirect meta-data blocks
+	 */
+	retval = free_ind_block(handle, inode, i_data);
+	ext4_mark_inode_dirty(handle, inode);
+
+err_out:
+	return retval;
+}
+
+static int free_ext_idx(handle_t *handle, struct inode *inode,
+					struct ext4_extent_idx *ix)
+{
+	int i, retval = 0;
+	ext4_fsblk_t block;
+	struct buffer_head *bh;
+	struct ext4_extent_header *eh;
+
+	block = ext4_idx_pblock(ix);
+	bh = sb_bread(inode->i_sb, block);
+	if (!bh)
+		return -EIO;
+
+	eh = (struct ext4_extent_header *)bh->b_data;
+	if (eh->eh_depth != 0) {
+		ix = EXT_FIRST_INDEX(eh);
+		for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
+			retval = free_ext_idx(handle, inode, ix);
+			if (retval)
+				break;
+		}
+	}
+	put_bh(bh);
+	extend_credit_for_blkdel(handle, inode);
+	ext4_free_blocks(handle, inode, NULL, block, 1,
+			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
+	return retval;
+}
+
+/*
+ * Free the extent meta data blocks only
+ */
+static int free_ext_block(handle_t *handle, struct inode *inode)
+{
+	int i, retval = 0;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
+	struct ext4_extent_idx *ix;
+	if (eh->eh_depth == 0)
+		/*
+		 * No extra blocks allocated for extent meta data
+		 */
+		return 0;
+	ix = EXT_FIRST_INDEX(eh);
+	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
+		retval = free_ext_idx(handle, inode, ix);
+		if (retval)
+			return retval;
+	}
+	return retval;
+}
+
+int ext4_ext_migrate(struct inode *inode)
+{
+	handle_t *handle;
+	int retval = 0, i;
+	__le32 *i_data;
+	struct ext4_inode_info *ei;
+	struct inode *tmp_inode = NULL;
+	struct migrate_struct lb;
+	unsigned long max_entries;
+	__u32 goal;
+	uid_t owner[2];
+
+	/*
+	 * If the filesystem does not support extents, or the inode
+	 * already is extent-based, error out.
+	 */
+	if (!EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb,
+				       EXT4_FEATURE_INCOMPAT_EXTENTS) ||
+	    (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		return -EINVAL;
+
+	if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
+		/*
+		 * don't migrate fast symlink
+		 */
+		return retval;
+
+	/*
+	 * Worst case we can touch the allocation bitmaps, a bgd
+	 * block, and a block to link in the orphan list.  We do need
+	 * need to worry about credits for modifying the quota inode.
+	 */
+	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE,
+		4 + EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
+
+	if (IS_ERR(handle)) {
+		retval = PTR_ERR(handle);
+		return retval;
+	}
+	goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) *
+		EXT4_INODES_PER_GROUP(inode->i_sb)) + 1;
+	owner[0] = i_uid_read(inode);
+	owner[1] = i_gid_read(inode);
+	tmp_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
+				   S_IFREG, NULL, goal, owner);
+	if (IS_ERR(tmp_inode)) {
+		retval = PTR_ERR(tmp_inode);
+		ext4_journal_stop(handle);
+		return retval;
+	}
+	i_size_write(tmp_inode, i_size_read(inode));
+	/*
+	 * Set the i_nlink to zero so it will be deleted later
+	 * when we drop inode reference.
+	 */
+	clear_nlink(tmp_inode);
+
+	ext4_ext_tree_init(handle, tmp_inode);
+	ext4_orphan_add(handle, tmp_inode);
+	ext4_journal_stop(handle);
+
+	/*
+	 * start with one credit accounted for
+	 * superblock modification.
+	 *
+	 * For the tmp_inode we already have committed the
+	 * transaction that created the inode. Later as and
+	 * when we add extents we extent the journal
+	 */
+	/*
+	 * Even though we take i_mutex we can still cause block
+	 * allocation via mmap write to holes. If we have allocated
+	 * new blocks we fail migrate.  New block allocation will
+	 * clear EXT4_STATE_EXT_MIGRATE flag.  The flag is updated
+	 * with i_data_sem held to prevent racing with block
+	 * allocation.
+	 */
+	down_read(&EXT4_I(inode)->i_data_sem);
+	ext4_set_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
+	up_read((&EXT4_I(inode)->i_data_sem));
+
+	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
+	if (IS_ERR(handle)) {
+		/*
+		 * It is impossible to update on-disk structures without
+		 * a handle, so just rollback in-core changes and live other
+		 * work to orphan_list_cleanup()
+		 */
+		ext4_orphan_del(NULL, tmp_inode);
+		retval = PTR_ERR(handle);
+		goto out;
+	}
+
+	ei = EXT4_I(inode);
+	i_data = ei->i_data;
+	memset(&lb, 0, sizeof(lb));
+
+	/* 32 bit block address 4 bytes */
+	max_entries = inode->i_sb->s_blocksize >> 2;
+	for (i = 0; i < EXT4_NDIR_BLOCKS; i++) {
+		if (i_data[i]) {
+			retval = update_extent_range(handle, tmp_inode,
+						le32_to_cpu(i_data[i]), &lb);
+			if (retval)
+				goto err_out;
+		} else
+			lb.curr_block++;
+	}
+	if (i_data[EXT4_IND_BLOCK]) {
+		retval = update_ind_extent_range(handle, tmp_inode,
+				le32_to_cpu(i_data[EXT4_IND_BLOCK]), &lb);
+			if (retval)
+				goto err_out;
+	} else
+		lb.curr_block += max_entries;
+	if (i_data[EXT4_DIND_BLOCK]) {
+		retval = update_dind_extent_range(handle, tmp_inode,
+				le32_to_cpu(i_data[EXT4_DIND_BLOCK]), &lb);
+			if (retval)
+				goto err_out;
+	} else
+		lb.curr_block += max_entries * max_entries;
+	if (i_data[EXT4_TIND_BLOCK]) {
+		retval = update_tind_extent_range(handle, tmp_inode,
+				le32_to_cpu(i_data[EXT4_TIND_BLOCK]), &lb);
+			if (retval)
+				goto err_out;
+	}
+	/*
+	 * Build the last extent
+	 */
+	retval = finish_range(handle, tmp_inode, &lb);
+err_out:
+	if (retval)
+		/*
+		 * Failure case delete the extent information with the
+		 * tmp_inode
+		 */
+		free_ext_block(handle, tmp_inode);
+	else {
+		retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
+		if (retval)
+			/*
+			 * if we fail to swap inode data free the extent
+			 * details of the tmp inode
+			 */
+			free_ext_block(handle, tmp_inode);
+	}
+
+	/* We mark the tmp_inode dirty via ext4_ext_tree_init. */
+	if (ext4_journal_extend(handle, 1) != 0)
+		ext4_journal_restart(handle, 1);
+
+	/*
+	 * Mark the tmp_inode as of size zero
+	 */
+	i_size_write(tmp_inode, 0);
+
+	/*
+	 * set the  i_blocks count to zero
+	 * so that the ext4_delete_inode does the
+	 * right job
+	 *
+	 * We don't need to take the i_lock because
+	 * the inode is not visible to user space.
+	 */
+	tmp_inode->i_blocks = 0;
+
+	/* Reset the extent details */
+	ext4_ext_tree_init(handle, tmp_inode);
+	ext4_journal_stop(handle);
+out:
+	unlock_new_inode(tmp_inode);
+	iput(tmp_inode);
+
+	return retval;
+}
+
+/*
+ * Migrate a simple extent-based inode to use the i_blocks[] array
+ */
+int ext4_ind_migrate(struct inode *inode)
+{
+	struct ext4_extent_header	*eh;
+	struct ext4_super_block		*es = EXT4_SB(inode->i_sb)->s_es;
+	struct ext4_inode_info		*ei = EXT4_I(inode);
+	struct ext4_extent		*ex;
+	unsigned int			i, len;
+	ext4_fsblk_t			blk;
+	handle_t			*handle;
+	int				ret;
+
+	if (!EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb,
+				       EXT4_FEATURE_INCOMPAT_EXTENTS) ||
+	    (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		return -EINVAL;
+
+	if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+				       EXT4_FEATURE_RO_COMPAT_BIGALLOC))
+		return -EOPNOTSUPP;
+
+	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+	ret = ext4_ext_check_inode(inode);
+	if (ret)
+		goto errout;
+
+	eh = ext_inode_hdr(inode);
+	ex  = EXT_FIRST_EXTENT(eh);
+	if (ext4_blocks_count(es) > EXT4_MAX_BLOCK_FILE_PHYS ||
+	    eh->eh_depth != 0 || le16_to_cpu(eh->eh_entries) > 1) {
+		ret = -EOPNOTSUPP;
+		goto errout;
+	}
+	if (eh->eh_entries == 0)
+		blk = len = 0;
+	else {
+		len = le16_to_cpu(ex->ee_len);
+		blk = ext4_ext_pblock(ex);
+		if (len > EXT4_NDIR_BLOCKS) {
+			ret = -EOPNOTSUPP;
+			goto errout;
+		}
+	}
+
+	ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
+	memset(ei->i_data, 0, sizeof(ei->i_data));
+	for (i=0; i < len; i++)
+		ei->i_data[i] = cpu_to_le32(blk++);
+	ext4_mark_inode_dirty(handle, inode);
+errout:
+	ext4_journal_stop(handle);
+	up_write(&EXT4_I(inode)->i_data_sem);
+	return ret;
+}

fs/ext4/mmp.c

@@ -0,0 +1,393 @@
+#include <linux/fs.h>
+#include <linux/random.h>
+#include <linux/buffer_head.h>
+#include <linux/utsname.h>
+#include <linux/kthread.h>
+
+#include "ext4.h"
+
+/* Checksumming functions */
+static __le32 ext4_mmp_csum(struct super_block *sb, struct mmp_struct *mmp)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int offset = offsetof(struct mmp_struct, mmp_checksum);
+	__u32 csum;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (char *)mmp, offset);
+
+	return cpu_to_le32(csum);
+}
+
+static int ext4_mmp_csum_verify(struct super_block *sb, struct mmp_struct *mmp)
+{
+	if (!ext4_has_metadata_csum(sb))
+		return 1;
+
+	return mmp->mmp_checksum == ext4_mmp_csum(sb, mmp);
+}
+
+static void ext4_mmp_csum_set(struct super_block *sb, struct mmp_struct *mmp)
+{
+	if (!ext4_has_metadata_csum(sb))
+		return;
+
+	mmp->mmp_checksum = ext4_mmp_csum(sb, mmp);
+}
+
+/*
+ * Write the MMP block using WRITE_SYNC to try to get the block on-disk
+ * faster.
+ */
+static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
+{
+	struct mmp_struct *mmp = (struct mmp_struct *)(bh->b_data);
+
+	/*
+	 * We protect against freezing so that we don't create dirty buffers
+	 * on frozen filesystem.
+	 */
+	sb_start_write(sb);
+	ext4_mmp_csum_set(sb, mmp);
+	mark_buffer_dirty(bh);
+	lock_buffer(bh);
+	bh->b_end_io = end_buffer_write_sync;
+	get_bh(bh);
+	submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);
+	wait_on_buffer(bh);
+	sb_end_write(sb);
+	if (unlikely(!buffer_uptodate(bh)))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Read the MMP block. It _must_ be read from disk and hence we clear the
+ * uptodate flag on the buffer.
+ */
+static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
+			  ext4_fsblk_t mmp_block)
+{
+	struct mmp_struct *mmp;
+
+	if (*bh)
+		clear_buffer_uptodate(*bh);
+
+	/* This would be sb_bread(sb, mmp_block), except we need to be sure
+	 * that the MD RAID device cache has been bypassed, and that the read
+	 * is not blocked in the elevator. */
+	if (!*bh)
+		*bh = sb_getblk(sb, mmp_block);
+	if (!*bh)
+		return -ENOMEM;
+	if (*bh) {
+		get_bh(*bh);
+		lock_buffer(*bh);
+		(*bh)->b_end_io = end_buffer_read_sync;
+		submit_bh(READ_SYNC | REQ_META | REQ_PRIO, *bh);
+		wait_on_buffer(*bh);
+		if (!buffer_uptodate(*bh)) {
+			brelse(*bh);
+			*bh = NULL;
+		}
+	}
+	if (unlikely(!*bh)) {
+		ext4_warning(sb, "Error while reading MMP block %llu",
+			     mmp_block);
+		return -EIO;
+	}
+
+	mmp = (struct mmp_struct *)((*bh)->b_data);
+	if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC ||
+	    !ext4_mmp_csum_verify(sb, mmp))
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * Dump as much information as possible to help the admin.
+ */
+void __dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
+		    const char *function, unsigned int line, const char *msg)
+{
+	__ext4_warning(sb, function, line, msg);
+	__ext4_warning(sb, function, line,
+		       "MMP failure info: last update time: %llu, last update "
+		       "node: %s, last update device: %s\n",
+		       (long long unsigned int) le64_to_cpu(mmp->mmp_time),
+		       mmp->mmp_nodename, mmp->mmp_bdevname);
+}
+
+/*
+ * kmmpd will update the MMP sequence every s_mmp_update_interval seconds
+ */
+static int kmmpd(void *data)
+{
+	struct super_block *sb = ((struct mmpd_data *) data)->sb;
+	struct buffer_head *bh = ((struct mmpd_data *) data)->bh;
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	struct mmp_struct *mmp;
+	ext4_fsblk_t mmp_block;
+	u32 seq = 0;
+	unsigned long failed_writes = 0;
+	int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
+	unsigned mmp_check_interval;
+	unsigned long last_update_time;
+	unsigned long diff;
+	int retval;
+
+	mmp_block = le64_to_cpu(es->s_mmp_block);
+	mmp = (struct mmp_struct *)(bh->b_data);
+	mmp->mmp_time = cpu_to_le64(get_seconds());
+	/*
+	 * Start with the higher mmp_check_interval and reduce it if
+	 * the MMP block is being updated on time.
+	 */
+	mmp_check_interval = max(EXT4_MMP_CHECK_MULT * mmp_update_interval,
+				 EXT4_MMP_MIN_CHECK_INTERVAL);
+	mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
+	bdevname(bh->b_bdev, mmp->mmp_bdevname);
+
+	memcpy(mmp->mmp_nodename, init_utsname()->nodename,
+	       sizeof(mmp->mmp_nodename));
+
+	while (!kthread_should_stop()) {
+		if (++seq > EXT4_MMP_SEQ_MAX)
+			seq = 1;
+
+		mmp->mmp_seq = cpu_to_le32(seq);
+		mmp->mmp_time = cpu_to_le64(get_seconds());
+		last_update_time = jiffies;
+
+		retval = write_mmp_block(sb, bh);
+		/*
+		 * Don't spew too many error messages. Print one every
+		 * (s_mmp_update_interval * 60) seconds.
+		 */
+		if (retval) {
+			if ((failed_writes % 60) == 0)
+				ext4_error(sb, "Error writing to MMP block");
+			failed_writes++;
+		}
+
+		if (!(le32_to_cpu(es->s_feature_incompat) &
+		    EXT4_FEATURE_INCOMPAT_MMP)) {
+			ext4_warning(sb, "kmmpd being stopped since MMP feature"
+				     " has been disabled.");
+			EXT4_SB(sb)->s_mmp_tsk = NULL;
+			goto failed;
+		}
+
+		if (sb->s_flags & MS_RDONLY) {
+			ext4_warning(sb, "kmmpd being stopped since filesystem "
+				     "has been remounted as readonly.");
+			EXT4_SB(sb)->s_mmp_tsk = NULL;
+			goto failed;
+		}
+
+		diff = jiffies - last_update_time;
+		if (diff < mmp_update_interval * HZ)
+			schedule_timeout_interruptible(mmp_update_interval *
+						       HZ - diff);
+
+		/*
+		 * We need to make sure that more than mmp_check_interval
+		 * seconds have not passed since writing. If that has happened
+		 * we need to check if the MMP block is as we left it.
+		 */
+		diff = jiffies - last_update_time;
+		if (diff > mmp_check_interval * HZ) {
+			struct buffer_head *bh_check = NULL;
+			struct mmp_struct *mmp_check;
+
+			retval = read_mmp_block(sb, &bh_check, mmp_block);
+			if (retval) {
+				ext4_error(sb, "error reading MMP data: %d",
+					   retval);
+
+				EXT4_SB(sb)->s_mmp_tsk = NULL;
+				goto failed;
+			}
+
+			mmp_check = (struct mmp_struct *)(bh_check->b_data);
+			if (mmp->mmp_seq != mmp_check->mmp_seq ||
+			    memcmp(mmp->mmp_nodename, mmp_check->mmp_nodename,
+				   sizeof(mmp->mmp_nodename))) {
+				dump_mmp_msg(sb, mmp_check,
+					     "Error while updating MMP info. "
+					     "The filesystem seems to have been"
+					     " multiply mounted.");
+				ext4_error(sb, "abort");
+				goto failed;
+			}
+			put_bh(bh_check);
+		}
+
+		 /*
+		 * Adjust the mmp_check_interval depending on how much time
+		 * it took for the MMP block to be written.
+		 */
+		mmp_check_interval = max(min(EXT4_MMP_CHECK_MULT * diff / HZ,
+					     EXT4_MMP_MAX_CHECK_INTERVAL),
+					 EXT4_MMP_MIN_CHECK_INTERVAL);
+		mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
+	}
+
+	/*
+	 * Unmount seems to be clean.
+	 */
+	mmp->mmp_seq = cpu_to_le32(EXT4_MMP_SEQ_CLEAN);
+	mmp->mmp_time = cpu_to_le64(get_seconds());
+
+	retval = write_mmp_block(sb, bh);
+
+failed:
+	kfree(data);
+	brelse(bh);
+	return retval;
+}
+
+/*
+ * Get a random new sequence number but make sure it is not greater than
+ * EXT4_MMP_SEQ_MAX.
+ */
+static unsigned int mmp_new_seq(void)
+{
+	u32 new_seq;
+
+	do {
+		new_seq = prandom_u32();
+	} while (new_seq > EXT4_MMP_SEQ_MAX);
+
+	return new_seq;
+}
+
+/*
+ * Protect the filesystem from being mounted more than once.
+ */
+int ext4_multi_mount_protect(struct super_block *sb,
+				    ext4_fsblk_t mmp_block)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	struct buffer_head *bh = NULL;
+	struct mmp_struct *mmp = NULL;
+	struct mmpd_data *mmpd_data;
+	u32 seq;
+	unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
+	unsigned int wait_time = 0;
+	int retval;
+
+	if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
+	    mmp_block >= ext4_blocks_count(es)) {
+		ext4_warning(sb, "Invalid MMP block in superblock");
+		goto failed;
+	}
+
+	retval = read_mmp_block(sb, &bh, mmp_block);
+	if (retval)
+		goto failed;
+
+	mmp = (struct mmp_struct *)(bh->b_data);
+
+	if (mmp_check_interval < EXT4_MMP_MIN_CHECK_INTERVAL)
+		mmp_check_interval = EXT4_MMP_MIN_CHECK_INTERVAL;
+
+	/*
+	 * If check_interval in MMP block is larger, use that instead of
+	 * update_interval from the superblock.
+	 */
+	if (le16_to_cpu(mmp->mmp_check_interval) > mmp_check_interval)
+		mmp_check_interval = le16_to_cpu(mmp->mmp_check_interval);
+
+	seq = le32_to_cpu(mmp->mmp_seq);
+	if (seq == EXT4_MMP_SEQ_CLEAN)
+		goto skip;
+
+	if (seq == EXT4_MMP_SEQ_FSCK) {
+		dump_mmp_msg(sb, mmp, "fsck is running on the filesystem");
+		goto failed;
+	}
+
+	wait_time = min(mmp_check_interval * 2 + 1,
+			mmp_check_interval + 60);
+
+	/* Print MMP interval if more than 20 secs. */
+	if (wait_time > EXT4_MMP_MIN_CHECK_INTERVAL * 4)
+		ext4_warning(sb, "MMP interval %u higher than expected, please"
+			     " wait.\n", wait_time * 2);
+
+	if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
+		ext4_warning(sb, "MMP startup interrupted, failing mount\n");
+		goto failed;
+	}
+
+	retval = read_mmp_block(sb, &bh, mmp_block);
+	if (retval)
+		goto failed;
+	mmp = (struct mmp_struct *)(bh->b_data);
+	if (seq != le32_to_cpu(mmp->mmp_seq)) {
+		dump_mmp_msg(sb, mmp,
+			     "Device is already active on another node.");
+		goto failed;
+	}
+
+skip:
+	/*
+	 * write a new random sequence number.
+	 */
+	seq = mmp_new_seq();
+	mmp->mmp_seq = cpu_to_le32(seq);
+
+	retval = write_mmp_block(sb, bh);
+	if (retval)
+		goto failed;
+
+	/*
+	 * wait for MMP interval and check mmp_seq.
+	 */
+	if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
+		ext4_warning(sb, "MMP startup interrupted, failing mount\n");
+		goto failed;
+	}
+
+	retval = read_mmp_block(sb, &bh, mmp_block);
+	if (retval)
+		goto failed;
+	mmp = (struct mmp_struct *)(bh->b_data);
+	if (seq != le32_to_cpu(mmp->mmp_seq)) {
+		dump_mmp_msg(sb, mmp,
+			     "Device is already active on another node.");
+		goto failed;
+	}
+
+	mmpd_data = kmalloc(sizeof(struct mmpd_data), GFP_KERNEL);
+	if (!mmpd_data) {
+		ext4_warning(sb, "not enough memory for mmpd_data");
+		goto failed;
+	}
+	mmpd_data->sb = sb;
+	mmpd_data->bh = bh;
+
+	/*
+	 * Start a kernel thread to update the MMP block periodically.
+	 */
+	EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, mmpd_data, "kmmpd-%s",
+					     bdevname(bh->b_bdev,
+						      mmp->mmp_bdevname));
+	if (IS_ERR(EXT4_SB(sb)->s_mmp_tsk)) {
+		EXT4_SB(sb)->s_mmp_tsk = NULL;
+		kfree(mmpd_data);
+		ext4_warning(sb, "Unable to create kmmpd thread for %s.",
+			     sb->s_id);
+		goto failed;
+	}
+
+	return 0;
+
+failed:
+	brelse(bh);
+	return 1;
+}
+
+

fs/ext4/move_extent.c

@@ -0,0 +1,684 @@
+/*
+ * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
+ * Written by Takashi Sato <t-sato@yk.jp.nec.com>
+ *            Akira Fujita <a-fujita@rs.jp.nec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/fs.h>
+#include <linux/quotaops.h>
+#include <linux/slab.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "ext4_extents.h"
+
+/**
+ * get_ext_path - Find an extent path for designated logical block number.
+ *
+ * @inode:	an inode which is searched
+ * @lblock:	logical block number to find an extent path
+ * @path:	pointer to an extent path pointer (for output)
+ *
+ * ext4_find_extent wrapper. Return 0 on success, or a negative error value
+ * on failure.
+ */
+static inline int
+get_ext_path(struct inode *inode, ext4_lblk_t lblock,
+		struct ext4_ext_path **ppath)
+{
+	struct ext4_ext_path *path;
+
+	path = ext4_find_extent(inode, lblock, ppath, EXT4_EX_NOCACHE);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	if (path[ext_depth(inode)].p_ext == NULL) {
+		ext4_ext_drop_refs(path);
+		kfree(path);
+		*ppath = NULL;
+		return -ENODATA;
+	}
+	*ppath = path;
+	return 0;
+}
+
+/**
+ * ext4_double_down_write_data_sem - Acquire two inodes' write lock
+ *                                   of i_data_sem
+ *
+ * Acquire write lock of i_data_sem of the two inodes
+ */
+void
+ext4_double_down_write_data_sem(struct inode *first, struct inode *second)
+{
+	if (first < second) {
+		down_write(&EXT4_I(first)->i_data_sem);
+		down_write_nested(&EXT4_I(second)->i_data_sem, SINGLE_DEPTH_NESTING);
+	} else {
+		down_write(&EXT4_I(second)->i_data_sem);
+		down_write_nested(&EXT4_I(first)->i_data_sem, SINGLE_DEPTH_NESTING);
+
+	}
+}
+
+/**
+ * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem
+ *
+ * @orig_inode:		original inode structure to be released its lock first
+ * @donor_inode:	donor inode structure to be released its lock second
+ * Release write lock of i_data_sem of two inodes (orig and donor).
+ */
+void
+ext4_double_up_write_data_sem(struct inode *orig_inode,
+			      struct inode *donor_inode)
+{
+	up_write(&EXT4_I(orig_inode)->i_data_sem);
+	up_write(&EXT4_I(donor_inode)->i_data_sem);
+}
+
+/**
+ * mext_check_coverage - Check that all extents in range has the same type
+ *
+ * @inode:		inode in question
+ * @from:		block offset of inode
+ * @count:		block count to be checked
+ * @unwritten:		extents expected to be unwritten
+ * @err:		pointer to save error value
+ *
+ * Return 1 if all extents in range has expected type, and zero otherwise.
+ */
+static int
+mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
+		    int unwritten, int *err)
+{
+	struct ext4_ext_path *path = NULL;
+	struct ext4_extent *ext;
+	int ret = 0;
+	ext4_lblk_t last = from + count;
+	while (from < last) {
+		*err = get_ext_path(inode, from, &path);
+		if (*err)
+			goto out;
+		ext = path[ext_depth(inode)].p_ext;
+		if (unwritten != ext4_ext_is_unwritten(ext))
+			goto out;
+		from += ext4_ext_get_actual_len(ext);
+		ext4_ext_drop_refs(path);
+	}
+	ret = 1;
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	return ret;
+}
+
+/**
+ * mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2
+ *
+ * @inode1:	the inode structure
+ * @inode2:	the inode structure
+ * @index1:	page index
+ * @index2:	page index
+ * @page:	result page vector
+ *
+ * Grab two locked pages for inode's by inode order
+ */
+static int
+mext_page_double_lock(struct inode *inode1, struct inode *inode2,
+		      pgoff_t index1, pgoff_t index2, struct page *page[2])
+{
+	struct address_space *mapping[2];
+	unsigned fl = AOP_FLAG_NOFS;
+
+	BUG_ON(!inode1 || !inode2);
+	if (inode1 < inode2) {
+		mapping[0] = inode1->i_mapping;
+		mapping[1] = inode2->i_mapping;
+	} else {
+		pgoff_t tmp = index1;
+		index1 = index2;
+		index2 = tmp;
+		mapping[0] = inode2->i_mapping;
+		mapping[1] = inode1->i_mapping;
+	}
+
+	page[0] = grab_cache_page_write_begin(mapping[0], index1, fl);
+	if (!page[0])
+		return -ENOMEM;
+
+	page[1] = grab_cache_page_write_begin(mapping[1], index2, fl);
+	if (!page[1]) {
+		unlock_page(page[0]);
+		page_cache_release(page[0]);
+		return -ENOMEM;
+	}
+	/*
+	 * grab_cache_page_write_begin() may not wait on page's writeback if
+	 * BDI not demand that. But it is reasonable to be very conservative
+	 * here and explicitly wait on page's writeback
+	 */
+	wait_on_page_writeback(page[0]);
+	wait_on_page_writeback(page[1]);
+	if (inode1 > inode2) {
+		struct page *tmp;
+		tmp = page[0];
+		page[0] = page[1];
+		page[1] = tmp;
+	}
+	return 0;
+}
+
+/* Force page buffers uptodate w/o dropping page's lock */
+static int
+mext_page_mkuptodate(struct page *page, unsigned from, unsigned to)
+{
+	struct inode *inode = page->mapping->host;
+	sector_t block;
+	struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
+	unsigned int blocksize, block_start, block_end;
+	int i, err,  nr = 0, partial = 0;
+	BUG_ON(!PageLocked(page));
+	BUG_ON(PageWriteback(page));
+
+	if (PageUptodate(page))
+		return 0;
+
+	blocksize = 1 << inode->i_blkbits;
+	if (!page_has_buffers(page))
+		create_empty_buffers(page, blocksize, 0);
+
+	head = page_buffers(page);
+	block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+	for (bh = head, block_start = 0; bh != head || !block_start;
+	     block++, block_start = block_end, bh = bh->b_this_page) {
+		block_end = block_start + blocksize;
+		if (block_end <= from || block_start >= to) {
+			if (!buffer_uptodate(bh))
+				partial = 1;
+			continue;
+		}
+		if (buffer_uptodate(bh))
+			continue;
+		if (!buffer_mapped(bh)) {
+			err = ext4_get_block(inode, block, bh, 0);
+			if (err) {
+				SetPageError(page);
+				return err;
+			}
+			if (!buffer_mapped(bh)) {
+				zero_user(page, block_start, blocksize);
+				set_buffer_uptodate(bh);
+				continue;
+			}
+		}
+		BUG_ON(nr >= MAX_BUF_PER_PAGE);
+		arr[nr++] = bh;
+	}
+	/* No io required */
+	if (!nr)
+		goto out;
+
+	for (i = 0; i < nr; i++) {
+		bh = arr[i];
+		if (!bh_uptodate_or_lock(bh)) {
+			err = bh_submit_read(bh);
+			if (err)
+				return err;
+		}
+	}
+out:
+	if (!partial)
+		SetPageUptodate(page);
+	return 0;
+}
+
+/**
+ * move_extent_per_page - Move extent data per page
+ *
+ * @o_filp:			file structure of original file
+ * @donor_inode:		donor inode
+ * @orig_page_offset:		page index on original file
+ * @donor_page_offset:		page index on donor file
+ * @data_offset_in_page:	block index where data swapping starts
+ * @block_len_in_page:		the number of blocks to be swapped
+ * @unwritten:			orig extent is unwritten or not
+ * @err:			pointer to save return value
+ *
+ * Save the data in original inode blocks and replace original inode extents
+ * with donor inode extents by calling ext4_swap_extents().
+ * Finally, write out the saved data in new original inode blocks. Return
+ * replaced block count.
+ */
+static int
+move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
+		     pgoff_t orig_page_offset, pgoff_t donor_page_offset,
+		     int data_offset_in_page,
+		     int block_len_in_page, int unwritten, int *err)
+{
+	struct inode *orig_inode = file_inode(o_filp);
+	struct page *pagep[2] = {NULL, NULL};
+	handle_t *handle;
+	ext4_lblk_t orig_blk_offset, donor_blk_offset;
+	unsigned long blocksize = orig_inode->i_sb->s_blocksize;
+	unsigned int w_flags = 0;
+	unsigned int tmp_data_size, data_size, replaced_size;
+	int err2, jblocks, retries = 0;
+	int replaced_count = 0;
+	int from = data_offset_in_page << orig_inode->i_blkbits;
+	int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
+
+	/*
+	 * It needs twice the amount of ordinary journal buffers because
+	 * inode and donor_inode may change each different metadata blocks.
+	 */
+again:
+	*err = 0;
+	jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
+	handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks);
+	if (IS_ERR(handle)) {
+		*err = PTR_ERR(handle);
+		return 0;
+	}
+
+	if (segment_eq(get_fs(), KERNEL_DS))
+		w_flags |= AOP_FLAG_UNINTERRUPTIBLE;
+
+	orig_blk_offset = orig_page_offset * blocks_per_page +
+		data_offset_in_page;
+
+	donor_blk_offset = donor_page_offset * blocks_per_page +
+		data_offset_in_page;
+
+	/* Calculate data_size */
+	if ((orig_blk_offset + block_len_in_page - 1) ==
+	    ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
+		/* Replace the last block */
+		tmp_data_size = orig_inode->i_size & (blocksize - 1);
+		/*
+		 * If data_size equal zero, it shows data_size is multiples of
+		 * blocksize. So we set appropriate value.
+		 */
+		if (tmp_data_size == 0)
+			tmp_data_size = blocksize;
+
+		data_size = tmp_data_size +
+			((block_len_in_page - 1) << orig_inode->i_blkbits);
+	} else
+		data_size = block_len_in_page << orig_inode->i_blkbits;
+
+	replaced_size = data_size;
+
+	*err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset,
+				     donor_page_offset, pagep);
+	if (unlikely(*err < 0))
+		goto stop_journal;
+	/*
+	 * If orig extent was unwritten it can become initialized
+	 * at any time after i_data_sem was dropped, in order to
+	 * serialize with delalloc we have recheck extent while we
+	 * hold page's lock, if it is still the case data copy is not
+	 * necessary, just swap data blocks between orig and donor.
+	 */
+	if (unwritten) {
+		ext4_double_down_write_data_sem(orig_inode, donor_inode);
+		/* If any of extents in range became initialized we have to
+		 * fallback to data copying */
+		unwritten = mext_check_coverage(orig_inode, orig_blk_offset,
+						block_len_in_page, 1, err);
+		if (*err)
+			goto drop_data_sem;
+
+		unwritten &= mext_check_coverage(donor_inode, donor_blk_offset,
+						 block_len_in_page, 1, err);
+		if (*err)
+			goto drop_data_sem;
+
+		if (!unwritten) {
+			ext4_double_up_write_data_sem(orig_inode, donor_inode);
+			goto data_copy;
+		}
+		if ((page_has_private(pagep[0]) &&
+		     !try_to_release_page(pagep[0], 0)) ||
+		    (page_has_private(pagep[1]) &&
+		     !try_to_release_page(pagep[1], 0))) {
+			*err = -EBUSY;
+			goto drop_data_sem;
+		}
+		replaced_count = ext4_swap_extents(handle, orig_inode,
+						   donor_inode, orig_blk_offset,
+						   donor_blk_offset,
+						   block_len_in_page, 1, err);
+	drop_data_sem:
+		ext4_double_up_write_data_sem(orig_inode, donor_inode);
+		goto unlock_pages;
+	}
+data_copy:
+	*err = mext_page_mkuptodate(pagep[0], from, from + replaced_size);
+	if (*err)
+		goto unlock_pages;
+
+	/* At this point all buffers in range are uptodate, old mapping layout
+	 * is no longer required, try to drop it now. */
+	if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) ||
+	    (page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) {
+		*err = -EBUSY;
+		goto unlock_pages;
+	}
+	ext4_double_down_write_data_sem(orig_inode, donor_inode);
+	replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode,
+					       orig_blk_offset, donor_blk_offset,
+					   block_len_in_page, 1, err);
+	ext4_double_up_write_data_sem(orig_inode, donor_inode);
+	if (*err) {
+		if (replaced_count) {
+			block_len_in_page = replaced_count;
+			replaced_size =
+				block_len_in_page << orig_inode->i_blkbits;
+		} else
+			goto unlock_pages;
+	}
+	/* Perform all necessary steps similar write_begin()/write_end()
+	 * but keeping in mind that i_size will not change */
+	*err = __block_write_begin(pagep[0], from, replaced_size,
+				   ext4_get_block);
+	if (!*err)
+		*err = block_commit_write(pagep[0], from, from + replaced_size);
+
+	if (unlikely(*err < 0))
+		goto repair_branches;
+
+	/* Even in case of data=writeback it is reasonable to pin
+	 * inode to transaction, to prevent unexpected data loss */
+	*err = ext4_jbd2_file_inode(handle, orig_inode);
+
+unlock_pages:
+	unlock_page(pagep[0]);
+	page_cache_release(pagep[0]);
+	unlock_page(pagep[1]);
+	page_cache_release(pagep[1]);
+stop_journal:
+	ext4_journal_stop(handle);
+	/* Buffer was busy because probably is pinned to journal transaction,
+	 * force transaction commit may help to free it. */
+	if (*err == -EBUSY && ext4_should_retry_alloc(orig_inode->i_sb,
+						      &retries))
+		goto again;
+	return replaced_count;
+
+repair_branches:
+	/*
+	 * This should never ever happen!
+	 * Extents are swapped already, but we are not able to copy data.
+	 * Try to swap extents to it's original places
+	 */
+	ext4_double_down_write_data_sem(orig_inode, donor_inode);
+	replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode,
+					       orig_blk_offset, donor_blk_offset,
+					   block_len_in_page, 0, &err2);
+	ext4_double_up_write_data_sem(orig_inode, donor_inode);
+	if (replaced_count != block_len_in_page) {
+		EXT4_ERROR_INODE_BLOCK(orig_inode, (sector_t)(orig_blk_offset),
+				       "Unable to copy data block,"
+				       " data will be lost.");
+		*err = -EIO;
+	}
+	replaced_count = 0;
+	goto unlock_pages;
+}
+
+/**
+ * mext_check_arguments - Check whether move extent can be done
+ *
+ * @orig_inode:		original inode
+ * @donor_inode:	donor inode
+ * @orig_start:		logical start offset in block for orig
+ * @donor_start:	logical start offset in block for donor
+ * @len:		the number of blocks to be moved
+ *
+ * Check the arguments of ext4_move_extents() whether the files can be
+ * exchanged with each other.
+ * Return 0 on success, or a negative error value on failure.
+ */
+static int
+mext_check_arguments(struct inode *orig_inode,
+		     struct inode *donor_inode, __u64 orig_start,
+		     __u64 donor_start, __u64 *len)
+{
+	__u64 orig_eof, donor_eof;
+	unsigned int blkbits = orig_inode->i_blkbits;
+	unsigned int blocksize = 1 << blkbits;
+
+	orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits;
+	donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits;
+
+
+	if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
+		ext4_debug("ext4 move extent: suid or sgid is set"
+			   " to donor file [ino:orig %lu, donor %lu]\n",
+			   orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
+		return -EPERM;
+
+	/* Ext4 move extent does not support swapfile */
+	if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
+		ext4_debug("ext4 move extent: The argument files should "
+			"not be swapfile [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EBUSY;
+	}
+
+	/* Ext4 move extent supports only extent based file */
+	if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) {
+		ext4_debug("ext4 move extent: orig file is not extents "
+			"based file [ino:orig %lu]\n", orig_inode->i_ino);
+		return -EOPNOTSUPP;
+	} else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) {
+		ext4_debug("ext4 move extent: donor file is not extents "
+			"based file [ino:donor %lu]\n", donor_inode->i_ino);
+		return -EOPNOTSUPP;
+	}
+
+	if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
+		ext4_debug("ext4 move extent: File size is 0 byte\n");
+		return -EINVAL;
+	}
+
+	/* Start offset should be same */
+	if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) !=
+	    (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) {
+		ext4_debug("ext4 move extent: orig and donor's start "
+			"offset are not alligned [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	if ((orig_start >= EXT_MAX_BLOCKS) ||
+	    (donor_start >= EXT_MAX_BLOCKS) ||
+	    (*len > EXT_MAX_BLOCKS) ||
+	    (donor_start + *len >= EXT_MAX_BLOCKS) ||
+	    (orig_start + *len >= EXT_MAX_BLOCKS))  {
+		ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
+			"[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS,
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+	if (orig_eof < orig_start + *len - 1)
+		*len = orig_eof - orig_start;
+	if (donor_eof < donor_start + *len - 1)
+		*len = donor_eof - donor_start;
+	if (!*len) {
+		ext4_debug("ext4 move extent: len should not be 0 "
+			"[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
+			donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * ext4_move_extents - Exchange the specified range of a file
+ *
+ * @o_filp:		file structure of the original file
+ * @d_filp:		file structure of the donor file
+ * @orig_blk:		start offset in block for orig
+ * @donor_blk:		start offset in block for donor
+ * @len:		the number of blocks to be moved
+ * @moved_len:		moved block length
+ *
+ * This function returns 0 and moved block length is set in moved_len
+ * if succeed, otherwise returns error value.
+ *
+ */
+int
+ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
+		  __u64 donor_blk, __u64 len, __u64 *moved_len)
+{
+	struct inode *orig_inode = file_inode(o_filp);
+	struct inode *donor_inode = file_inode(d_filp);
+	struct ext4_ext_path *path = NULL;
+	int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
+	ext4_lblk_t o_end, o_start = orig_blk;
+	ext4_lblk_t d_start = donor_blk;
+	int ret;
+
+	if (orig_inode->i_sb != donor_inode->i_sb) {
+		ext4_debug("ext4 move extent: The argument files "
+			"should be in same FS [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	/* orig and donor should be different inodes */
+	if (orig_inode == donor_inode) {
+		ext4_debug("ext4 move extent: The argument files should not "
+			"be same inode [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	/* Regular file check */
+	if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
+		ext4_debug("ext4 move extent: The argument files should be "
+			"regular file [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+	/* TODO: This is non obvious task to swap blocks for inodes with full
+	   jornaling enabled */
+	if (ext4_should_journal_data(orig_inode) ||
+	    ext4_should_journal_data(donor_inode)) {
+		return -EINVAL;
+	}
+	/* Protect orig and donor inodes against a truncate */
+	lock_two_nondirectories(orig_inode, donor_inode);
+
+	/* Wait for all existing dio workers */
+	ext4_inode_block_unlocked_dio(orig_inode);
+	ext4_inode_block_unlocked_dio(donor_inode);
+	inode_dio_wait(orig_inode);
+	inode_dio_wait(donor_inode);
+
+	/* Protect extent tree against block allocations via delalloc */
+	ext4_double_down_write_data_sem(orig_inode, donor_inode);
+	/* Check the filesystem environment whether move_extent can be done */
+	ret = mext_check_arguments(orig_inode, donor_inode, orig_blk,
+				    donor_blk, &len);
+	if (ret)
+		goto out;
+	o_end = o_start + len;
+
+	while (o_start < o_end) {
+		struct ext4_extent *ex;
+		ext4_lblk_t cur_blk, next_blk;
+		pgoff_t orig_page_index, donor_page_index;
+		int offset_in_page;
+		int unwritten, cur_len;
+
+		ret = get_ext_path(orig_inode, o_start, &path);
+		if (ret)
+			goto out;
+		ex = path[path->p_depth].p_ext;
+		next_blk = ext4_ext_next_allocated_block(path);
+		cur_blk = le32_to_cpu(ex->ee_block);
+		cur_len = ext4_ext_get_actual_len(ex);
+		/* Check hole before the start pos */
+		if (cur_blk + cur_len - 1 < o_start) {
+			if (next_blk == EXT_MAX_BLOCKS) {
+				o_start = o_end;
+				ret = -ENODATA;
+				goto out;
+			}
+			d_start += next_blk - o_start;
+			o_start = next_blk;
+			continue;
+		/* Check hole after the start pos */
+		} else if (cur_blk > o_start) {
+			/* Skip hole */
+			d_start += cur_blk - o_start;
+			o_start = cur_blk;
+			/* Extent inside requested range ?*/
+			if (cur_blk >= o_end)
+				goto out;
+		} else { /* in_range(o_start, o_blk, o_len) */
+			cur_len += cur_blk - o_start;
+		}
+		unwritten = ext4_ext_is_unwritten(ex);
+		if (o_end - o_start < cur_len)
+			cur_len = o_end - o_start;
+
+		orig_page_index = o_start >> (PAGE_CACHE_SHIFT -
+					       orig_inode->i_blkbits);
+		donor_page_index = d_start >> (PAGE_CACHE_SHIFT -
+					       donor_inode->i_blkbits);
+		offset_in_page = o_start % blocks_per_page;
+		if (cur_len > blocks_per_page- offset_in_page)
+			cur_len = blocks_per_page - offset_in_page;
+		/*
+		 * Up semaphore to avoid following problems:
+		 * a. transaction deadlock among ext4_journal_start,
+		 *    ->write_begin via pagefault, and jbd2_journal_commit
+		 * b. racing with ->readpage, ->write_begin, and ext4_get_block
+		 *    in move_extent_per_page
+		 */
+		ext4_double_up_write_data_sem(orig_inode, donor_inode);
+		/* Swap original branches with new branches */
+		move_extent_per_page(o_filp, donor_inode,
+				     orig_page_index, donor_page_index,
+				     offset_in_page, cur_len,
+				     unwritten, &ret);
+		ext4_double_down_write_data_sem(orig_inode, donor_inode);
+		if (ret < 0)
+			break;
+		o_start += cur_len;
+		d_start += cur_len;
+	}
+	*moved_len = o_start - orig_blk;
+	if (*moved_len > len)
+		*moved_len = len;
+
+out:
+	if (*moved_len) {
+		ext4_discard_preallocations(orig_inode);
+		ext4_discard_preallocations(donor_inode);
+	}
+
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	ext4_double_up_write_data_sem(orig_inode, donor_inode);
+	ext4_inode_resume_unlocked_dio(orig_inode);
+	ext4_inode_resume_unlocked_dio(donor_inode);
+	unlock_two_nondirectories(orig_inode, donor_inode);
+
+	return ret;
+}

fs/ext4/page-io.c

@@ -0,0 +1,497 @@
+/*
+ * linux/fs/ext4/page-io.c
+ *
+ * This contains the new page_io functions for ext4
+ *
+ * Written by Theodore Ts'o, 2010.
+ */
+
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/jbd2.h>
+#include <linux/highuid.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/string.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include <linux/mpage.h>
+#include <linux/namei.h>
+#include <linux/aio.h>
+#include <linux/uio.h>
+#include <linux/bio.h>
+#include <linux/workqueue.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/ratelimit.h>
+
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+
+static struct kmem_cache *io_end_cachep;
+
+int __init ext4_init_pageio(void)
+{
+	io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
+	if (io_end_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+void ext4_exit_pageio(void)
+{
+	kmem_cache_destroy(io_end_cachep);
+}
+
+/*
+ * Print an buffer I/O error compatible with the fs/buffer.c.  This
+ * provides compatibility with dmesg scrapers that look for a specific
+ * buffer I/O error message.  We really need a unified error reporting
+ * structure to userspace ala Digital Unix's uerf system, but it's
+ * probably not going to happen in my lifetime, due to LKML politics...
+ */
+static void buffer_io_error(struct buffer_head *bh)
+{
+	char b[BDEVNAME_SIZE];
+	printk_ratelimited(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n",
+			bdevname(bh->b_bdev, b),
+			(unsigned long long)bh->b_blocknr);
+}
+
+static void ext4_finish_bio(struct bio *bio)
+{
+	int i;
+	int error = !test_bit(BIO_UPTODATE, &bio->bi_flags);
+	struct bio_vec *bvec;
+
+	bio_for_each_segment_all(bvec, bio, i) {
+		struct page *page = bvec->bv_page;
+		struct buffer_head *bh, *head;
+		unsigned bio_start = bvec->bv_offset;
+		unsigned bio_end = bio_start + bvec->bv_len;
+		unsigned under_io = 0;
+		unsigned long flags;
+
+		if (!page)
+			continue;
+
+		if (error) {
+			SetPageError(page);
+			set_bit(AS_EIO, &page->mapping->flags);
+		}
+		bh = head = page_buffers(page);
+		/*
+		 * We check all buffers in the page under BH_Uptodate_Lock
+		 * to avoid races with other end io clearing async_write flags
+		 */
+		local_irq_save(flags);
+		bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
+		do {
+			if (bh_offset(bh) < bio_start ||
+			    bh_offset(bh) + bh->b_size > bio_end) {
+				if (buffer_async_write(bh))
+					under_io++;
+				continue;
+			}
+			clear_buffer_async_write(bh);
+			if (error)
+				buffer_io_error(bh);
+		} while ((bh = bh->b_this_page) != head);
+		bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
+		local_irq_restore(flags);
+		if (!under_io)
+			end_page_writeback(page);
+	}
+}
+
+static void ext4_release_io_end(ext4_io_end_t *io_end)
+{
+	struct bio *bio, *next_bio;
+
+	BUG_ON(!list_empty(&io_end->list));
+	BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
+	WARN_ON(io_end->handle);
+
+	if (atomic_dec_and_test(&EXT4_I(io_end->inode)->i_ioend_count))
+		wake_up_all(ext4_ioend_wq(io_end->inode));
+
+	for (bio = io_end->bio; bio; bio = next_bio) {
+		next_bio = bio->bi_private;
+		ext4_finish_bio(bio);
+		bio_put(bio);
+	}
+	kmem_cache_free(io_end_cachep, io_end);
+}
+
+static void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
+{
+	struct inode *inode = io_end->inode;
+
+	io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
+	/* Wake up anyone waiting on unwritten extent conversion */
+	if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
+		wake_up_all(ext4_ioend_wq(inode));
+}
+
+/*
+ * Check a range of space and convert unwritten extents to written. Note that
+ * we are protected from truncate touching same part of extent tree by the
+ * fact that truncate code waits for all DIO to finish (thus exclusion from
+ * direct IO is achieved) and also waits for PageWriteback bits. Thus we
+ * cannot get to ext4_ext_truncate() before all IOs overlapping that range are
+ * completed (happens from ext4_free_ioend()).
+ */
+static int ext4_end_io(ext4_io_end_t *io)
+{
+	struct inode *inode = io->inode;
+	loff_t offset = io->offset;
+	ssize_t size = io->size;
+	handle_t *handle = io->handle;
+	int ret = 0;
+
+	ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
+		   "list->prev 0x%p\n",
+		   io, inode->i_ino, io->list.next, io->list.prev);
+
+	io->handle = NULL;	/* Following call will use up the handle */
+	ret = ext4_convert_unwritten_extents(handle, inode, offset, size);
+	if (ret < 0) {
+		ext4_msg(inode->i_sb, KERN_EMERG,
+			 "failed to convert unwritten extents to written "
+			 "extents -- potential data loss!  "
+			 "(inode %lu, offset %llu, size %zd, error %d)",
+			 inode->i_ino, offset, size, ret);
+	}
+	ext4_clear_io_unwritten_flag(io);
+	ext4_release_io_end(io);
+	return ret;
+}
+
+static void dump_completed_IO(struct inode *inode, struct list_head *head)
+{
+#ifdef	EXT4FS_DEBUG
+	struct list_head *cur, *before, *after;
+	ext4_io_end_t *io, *io0, *io1;
+
+	if (list_empty(head))
+		return;
+
+	ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
+	list_for_each_entry(io, head, list) {
+		cur = &io->list;
+		before = cur->prev;
+		io0 = container_of(before, ext4_io_end_t, list);
+		after = cur->next;
+		io1 = container_of(after, ext4_io_end_t, list);
+
+		ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
+			    io, inode->i_ino, io0, io1);
+	}
+#endif
+}
+
+/* Add the io_end to per-inode completed end_io list. */
+static void ext4_add_complete_io(ext4_io_end_t *io_end)
+{
+	struct ext4_inode_info *ei = EXT4_I(io_end->inode);
+	struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);
+	struct workqueue_struct *wq;
+	unsigned long flags;
+
+	/* Only reserved conversions from writeback should enter here */
+	WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
+	WARN_ON(!io_end->handle && sbi->s_journal);
+	spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+	wq = sbi->rsv_conversion_wq;
+	if (list_empty(&ei->i_rsv_conversion_list))
+		queue_work(wq, &ei->i_rsv_conversion_work);
+	list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);
+	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+}
+
+static int ext4_do_flush_completed_IO(struct inode *inode,
+				      struct list_head *head)
+{
+	ext4_io_end_t *io;
+	struct list_head unwritten;
+	unsigned long flags;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	int err, ret = 0;
+
+	spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+	dump_completed_IO(inode, head);
+	list_replace_init(head, &unwritten);
+	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+
+	while (!list_empty(&unwritten)) {
+		io = list_entry(unwritten.next, ext4_io_end_t, list);
+		BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN));
+		list_del_init(&io->list);
+
+		err = ext4_end_io(io);
+		if (unlikely(!ret && err))
+			ret = err;
+	}
+	return ret;
+}
+
+/*
+ * work on completed IO, to convert unwritten extents to extents
+ */
+void ext4_end_io_rsv_work(struct work_struct *work)
+{
+	struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
+						  i_rsv_conversion_work);
+	ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);
+}
+
+ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
+{
+	ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags);
+	if (io) {
+		atomic_inc(&EXT4_I(inode)->i_ioend_count);
+		io->inode = inode;
+		INIT_LIST_HEAD(&io->list);
+		atomic_set(&io->count, 1);
+	}
+	return io;
+}
+
+void ext4_put_io_end_defer(ext4_io_end_t *io_end)
+{
+	if (atomic_dec_and_test(&io_end->count)) {
+		if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || !io_end->size) {
+			ext4_release_io_end(io_end);
+			return;
+		}
+		ext4_add_complete_io(io_end);
+	}
+}
+
+int ext4_put_io_end(ext4_io_end_t *io_end)
+{
+	int err = 0;
+
+	if (atomic_dec_and_test(&io_end->count)) {
+		if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
+			err = ext4_convert_unwritten_extents(io_end->handle,
+						io_end->inode, io_end->offset,
+						io_end->size);
+			io_end->handle = NULL;
+			ext4_clear_io_unwritten_flag(io_end);
+		}
+		ext4_release_io_end(io_end);
+	}
+	return err;
+}
+
+ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)
+{
+	atomic_inc(&io_end->count);
+	return io_end;
+}
+
+/* BIO completion function for page writeback */
+static void ext4_end_bio(struct bio *bio, int error)
+{
+	ext4_io_end_t *io_end = bio->bi_private;
+	sector_t bi_sector = bio->bi_iter.bi_sector;
+
+	BUG_ON(!io_end);
+	bio->bi_end_io = NULL;
+	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
+		error = 0;
+
+	if (error) {
+		struct inode *inode = io_end->inode;
+
+		ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
+			     "(offset %llu size %ld starting block %llu)",
+			     error, inode->i_ino,
+			     (unsigned long long) io_end->offset,
+			     (long) io_end->size,
+			     (unsigned long long)
+			     bi_sector >> (inode->i_blkbits - 9));
+		mapping_set_error(inode->i_mapping, error);
+	}
+
+	if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
+		/*
+		 * Link bio into list hanging from io_end. We have to do it
+		 * atomically as bio completions can be racing against each
+		 * other.
+		 */
+		bio->bi_private = xchg(&io_end->bio, bio);
+		ext4_put_io_end_defer(io_end);
+	} else {
+		/*
+		 * Drop io_end reference early. Inode can get freed once
+		 * we finish the bio.
+		 */
+		ext4_put_io_end_defer(io_end);
+		ext4_finish_bio(bio);
+		bio_put(bio);
+	}
+}
+
+void ext4_io_submit(struct ext4_io_submit *io)
+{
+	struct bio *bio = io->io_bio;
+
+	if (bio) {
+		bio_get(io->io_bio);
+		submit_bio(io->io_op, io->io_bio);
+		BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP));
+		bio_put(io->io_bio);
+	}
+	io->io_bio = NULL;
+}
+
+void ext4_io_submit_init(struct ext4_io_submit *io,
+			 struct writeback_control *wbc)
+{
+	io->io_op = (wbc->sync_mode == WB_SYNC_ALL ?  WRITE_SYNC : WRITE);
+	io->io_bio = NULL;
+	io->io_end = NULL;
+}
+
+static int io_submit_init_bio(struct ext4_io_submit *io,
+			      struct buffer_head *bh)
+{
+	int nvecs = bio_get_nr_vecs(bh->b_bdev);
+	struct bio *bio;
+
+	bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES));
+	if (!bio)
+		return -ENOMEM;
+	bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
+	bio->bi_bdev = bh->b_bdev;
+	bio->bi_end_io = ext4_end_bio;
+	bio->bi_private = ext4_get_io_end(io->io_end);
+	io->io_bio = bio;
+	io->io_next_block = bh->b_blocknr;
+	return 0;
+}
+
+static int io_submit_add_bh(struct ext4_io_submit *io,
+			    struct inode *inode,
+			    struct buffer_head *bh)
+{
+	int ret;
+
+	if (io->io_bio && bh->b_blocknr != io->io_next_block) {
+submit_and_retry:
+		ext4_io_submit(io);
+	}
+	if (io->io_bio == NULL) {
+		ret = io_submit_init_bio(io, bh);
+		if (ret)
+			return ret;
+	}
+	ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh));
+	if (ret != bh->b_size)
+		goto submit_and_retry;
+	io->io_next_block++;
+	return 0;
+}
+
+int ext4_bio_write_page(struct ext4_io_submit *io,
+			struct page *page,
+			int len,
+			struct writeback_control *wbc,
+			bool keep_towrite)
+{
+	struct inode *inode = page->mapping->host;
+	unsigned block_start, blocksize;
+	struct buffer_head *bh, *head;
+	int ret = 0;
+	int nr_submitted = 0;
+
+	blocksize = 1 << inode->i_blkbits;
+
+	BUG_ON(!PageLocked(page));
+	BUG_ON(PageWriteback(page));
+
+	if (keep_towrite)
+		set_page_writeback_keepwrite(page);
+	else
+		set_page_writeback(page);
+	ClearPageError(page);
+
+	/*
+	 * Comments copied from block_write_full_page:
+	 *
+	 * The page straddles i_size.  It must be zeroed out on each and every
+	 * writepage invocation because it may be mmapped.  "A file is mapped
+	 * in multiples of the page size.  For a file that is not a multiple of
+	 * the page size, the remaining memory is zeroed when mapped, and
+	 * writes to that region are not written out to the file."
+	 */
+	if (len < PAGE_CACHE_SIZE)
+		zero_user_segment(page, len, PAGE_CACHE_SIZE);
+	/*
+	 * In the first loop we prepare and mark buffers to submit. We have to
+	 * mark all buffers in the page before submitting so that
+	 * end_page_writeback() cannot be called from ext4_bio_end_io() when IO
+	 * on the first buffer finishes and we are still working on submitting
+	 * the second buffer.
+	 */
+	bh = head = page_buffers(page);
+	do {
+		block_start = bh_offset(bh);
+		if (block_start >= len) {
+			clear_buffer_dirty(bh);
+			set_buffer_uptodate(bh);
+			continue;
+		}
+		if (!buffer_dirty(bh) || buffer_delay(bh) ||
+		    !buffer_mapped(bh) || buffer_unwritten(bh)) {
+			/* A hole? We can safely clear the dirty bit */
+			if (!buffer_mapped(bh))
+				clear_buffer_dirty(bh);
+			if (io->io_bio)
+				ext4_io_submit(io);
+			continue;
+		}
+		if (buffer_new(bh)) {
+			clear_buffer_new(bh);
+			unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+		}
+		set_buffer_async_write(bh);
+	} while ((bh = bh->b_this_page) != head);
+
+	/* Now submit buffers to write */
+	bh = head = page_buffers(page);
+	do {
+		if (!buffer_async_write(bh))
+			continue;
+		ret = io_submit_add_bh(io, inode, bh);
+		if (ret) {
+			/*
+			 * We only get here on ENOMEM.  Not much else
+			 * we can do but mark the page as dirty, and
+			 * better luck next time.
+			 */
+			redirty_page_for_writepage(wbc, page);
+			break;
+		}
+		nr_submitted++;
+		clear_buffer_dirty(bh);
+	} while ((bh = bh->b_this_page) != head);
+
+	/* Error stopped previous loop? Clean up buffers... */
+	if (ret) {
+		do {
+			clear_buffer_async_write(bh);
+			bh = bh->b_this_page;
+		} while (bh != head);
+	}
+	unlock_page(page);
+	/* Nothing submitted - we have to end page writeback */
+	if (!nr_submitted)
+		end_page_writeback(page);
+	return ret;
+}

fs/ext4/symlink.c

@@ -0,0 +1,52 @@
+/*
+ *  linux/fs/ext4/symlink.c
+ *
+ * Only fast symlinks left here - the rest is done by generic code. AV, 1999
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/symlink.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 symlink handling code
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/namei.h>
+#include "ext4.h"
+#include "xattr.h"
+
+static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct ext4_inode_info *ei = EXT4_I(dentry->d_inode);
+	nd_set_link(nd, (char *) ei->i_data);
+	return NULL;
+}
+
+const struct inode_operations ext4_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= page_follow_link_light,
+	.put_link	= page_put_link,
+	.setattr	= ext4_setattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext4_listxattr,
+	.removexattr	= generic_removexattr,
+};
+
+const struct inode_operations ext4_fast_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= ext4_follow_link,
+	.setattr	= ext4_setattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext4_listxattr,
+	.removexattr	= generic_removexattr,
+};

fs/ext4/truncate.h

@@ -0,0 +1,43 @@
+/*
+ * linux/fs/ext4/truncate.h
+ *
+ * Common inline functions needed for truncate support
+ */
+
+/*
+ * Truncate blocks that were not used by write. We have to truncate the
+ * pagecache as well so that corresponding buffers get properly unmapped.
+ */
+static inline void ext4_truncate_failed_write(struct inode *inode)
+{
+	truncate_inode_pages(inode->i_mapping, inode->i_size);
+	ext4_truncate(inode);
+}
+
+/*
+ * Work out how many blocks we need to proceed with the next chunk of a
+ * truncate transaction.
+ */
+static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
+{
+	ext4_lblk_t needed;
+
+	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
+
+	/* Give ourselves just enough room to cope with inodes in which
+	 * i_blocks is corrupt: we've seen disk corruptions in the past
+	 * which resulted in random data in an inode which looked enough
+	 * like a regular file for ext4 to try to delete it.  Things
+	 * will go a bit crazy if that happens, but at least we should
+	 * try not to panic the whole kernel. */
+	if (needed < 2)
+		needed = 2;
+
+	/* But we need to bound the transaction so we don't overflow the
+	 * journal. */
+	if (needed > EXT4_MAX_TRANS_DATA)
+		needed = EXT4_MAX_TRANS_DATA;
+
+	return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
+}
+

fs/ext4/xattr.h

@@ -0,0 +1,136 @@
+/*
+  File: fs/ext4/xattr.h
+
+  On-disk format of extended attributes for the ext4 filesystem.
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define EXT4_XATTR_MAGIC		0xEA020000
+
+/* Maximum number of references to one attribute block */
+#define EXT4_XATTR_REFCOUNT_MAX		1024
+
+/* Name indexes */
+#define EXT4_XATTR_INDEX_USER			1
+#define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS	2
+#define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT	3
+#define EXT4_XATTR_INDEX_TRUSTED		4
+#define	EXT4_XATTR_INDEX_LUSTRE			5
+#define EXT4_XATTR_INDEX_SECURITY	        6
+#define EXT4_XATTR_INDEX_SYSTEM			7
+#define EXT4_XATTR_INDEX_RICHACL		8
+
+struct ext4_xattr_header {
+	__le32	h_magic;	/* magic number for identification */
+	__le32	h_refcount;	/* reference count */
+	__le32	h_blocks;	/* number of disk blocks used */
+	__le32	h_hash;		/* hash value of all attributes */
+	__le32	h_checksum;	/* crc32c(uuid+id+xattrblock) */
+				/* id = inum if refcount=1, blknum otherwise */
+	__u32	h_reserved[3];	/* zero right now */
+};
+
+struct ext4_xattr_ibody_header {
+	__le32	h_magic;	/* magic number for identification */
+};
+
+struct ext4_xattr_entry {
+	__u8	e_name_len;	/* length of name */
+	__u8	e_name_index;	/* attribute name index */
+	__le16	e_value_offs;	/* offset in disk block of value */
+	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
+	__le32	e_value_size;	/* size of attribute value */
+	__le32	e_hash;		/* hash value of name and value */
+	char	e_name[0];	/* attribute name */
+};
+
+#define EXT4_XATTR_PAD_BITS		2
+#define EXT4_XATTR_PAD		(1<<EXT4_XATTR_PAD_BITS)
+#define EXT4_XATTR_ROUND		(EXT4_XATTR_PAD-1)
+#define EXT4_XATTR_LEN(name_len) \
+	(((name_len) + EXT4_XATTR_ROUND + \
+	sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
+#define EXT4_XATTR_NEXT(entry) \
+	((struct ext4_xattr_entry *)( \
+	 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
+#define EXT4_XATTR_SIZE(size) \
+	(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
+
+#define IHDR(inode, raw_inode) \
+	((struct ext4_xattr_ibody_header *) \
+		((void *)raw_inode + \
+		EXT4_GOOD_OLD_INODE_SIZE + \
+		EXT4_I(inode)->i_extra_isize))
+#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
+
+#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
+#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
+#define BFIRST(bh) ENTRY(BHDR(bh)+1)
+#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#define EXT4_ZERO_XATTR_VALUE ((void *)-1)
+
+struct ext4_xattr_info {
+	int name_index;
+	const char *name;
+	const void *value;
+	size_t value_len;
+};
+
+struct ext4_xattr_search {
+	struct ext4_xattr_entry *first;
+	void *base;
+	void *end;
+	struct ext4_xattr_entry *here;
+	int not_found;
+};
+
+struct ext4_xattr_ibody_find {
+	struct ext4_xattr_search s;
+	struct ext4_iloc iloc;
+};
+
+extern const struct xattr_handler ext4_xattr_user_handler;
+extern const struct xattr_handler ext4_xattr_trusted_handler;
+extern const struct xattr_handler ext4_xattr_security_handler;
+
+extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
+
+extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
+extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
+extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
+
+extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
+extern void ext4_xattr_put_super(struct super_block *);
+
+extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
+			    struct ext4_inode *raw_inode, handle_t *handle);
+
+extern const struct xattr_handler *ext4_xattr_handlers[];
+
+extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
+				 struct ext4_xattr_ibody_find *is);
+extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
+				const char *name,
+				void *buffer, size_t buffer_size);
+extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
+				       struct ext4_xattr_info *i,
+				       struct ext4_xattr_ibody_find *is);
+
+extern struct mb_cache *ext4_xattr_create_cache(char *name);
+extern void ext4_xattr_destroy_cache(struct mb_cache *);
+
+#ifdef CONFIG_EXT4_FS_SECURITY
+extern int ext4_init_security(handle_t *handle, struct inode *inode,
+			      struct inode *dir, const struct qstr *qstr);
+#else
+static inline int ext4_init_security(handle_t *handle, struct inode *inode,
+				     struct inode *dir, const struct qstr *qstr)
+{
+	return 0;
+}
+#endif

fs/ext4/xattr_security.c

@@ -0,0 +1,82 @@
+/*
+ * linux/fs/ext4/xattr_security.c
+ * Handler for storing security labels as extended attributes.
+ */
+
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+
+static size_t
+ext4_xattr_security_list(struct dentry *dentry, char *list, size_t list_size,
+		const char *name, size_t name_len, int type)
+{
+	const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
+	const size_t total_len = prefix_len + name_len + 1;
+
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext4_xattr_security_get(struct dentry *dentry, const char *name,
+		       void *buffer, size_t size, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext4_xattr_get(dentry->d_inode, EXT4_XATTR_INDEX_SECURITY,
+			      name, buffer, size);
+}
+
+static int
+ext4_xattr_security_set(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext4_xattr_set(dentry->d_inode, EXT4_XATTR_INDEX_SECURITY,
+			      name, value, size, flags);
+}
+
+static int
+ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		void *fs_info)
+{
+	const struct xattr *xattr;
+	handle_t *handle = fs_info;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = ext4_xattr_set_handle(handle, inode,
+					    EXT4_XATTR_INDEX_SECURITY,
+					    xattr->name, xattr->value,
+					    xattr->value_len, 0);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
+int
+ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
+		   const struct qstr *qstr)
+{
+	return security_inode_init_security(inode, dir, qstr,
+					    &ext4_initxattrs, handle);
+}
+
+const struct xattr_handler ext4_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.list	= ext4_xattr_security_list,
+	.get	= ext4_xattr_security_get,
+	.set	= ext4_xattr_security_set,
+};

fs/ext4/xattr_trusted.c

@@ -0,0 +1,58 @@
+/*
+ * linux/fs/ext4/xattr_trusted.c
+ * Handler for trusted extended attributes.
+ *
+ * Copyright (C) 2003 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+#include <linux/string.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+
+static size_t
+ext4_xattr_trusted_list(struct dentry *dentry, char *list, size_t list_size,
+		const char *name, size_t name_len, int type)
+{
+	const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
+	const size_t total_len = prefix_len + name_len + 1;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return 0;
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext4_xattr_trusted_get(struct dentry *dentry, const char *name, void *buffer,
+		size_t size, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext4_xattr_get(dentry->d_inode, EXT4_XATTR_INDEX_TRUSTED,
+			      name, buffer, size);
+}
+
+static int
+ext4_xattr_trusted_set(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext4_xattr_set(dentry->d_inode, EXT4_XATTR_INDEX_TRUSTED,
+			      name, value, size, flags);
+}
+
+const struct xattr_handler ext4_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.list	= ext4_xattr_trusted_list,
+	.get	= ext4_xattr_trusted_get,
+	.set	= ext4_xattr_trusted_set,
+};

fs/ext4/xattr_user.c

@@ -0,0 +1,61 @@
+/*
+ * linux/fs/ext4/xattr_user.c
+ * Handler for extended user attributes.
+ *
+ * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+#include <linux/string.h>
+#include <linux/fs.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+
+static size_t
+ext4_xattr_user_list(struct dentry *dentry, char *list, size_t list_size,
+		     const char *name, size_t name_len, int type)
+{
+	const size_t prefix_len = XATTR_USER_PREFIX_LEN;
+	const size_t total_len = prefix_len + name_len + 1;
+
+	if (!test_opt(dentry->d_sb, XATTR_USER))
+		return 0;
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_USER_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext4_xattr_user_get(struct dentry *dentry, const char *name,
+		    void *buffer, size_t size, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	if (!test_opt(dentry->d_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+	return ext4_xattr_get(dentry->d_inode, EXT4_XATTR_INDEX_USER,
+			      name, buffer, size);
+}
+
+static int
+ext4_xattr_user_set(struct dentry *dentry, const char *name,
+		    const void *value, size_t size, int flags, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	if (!test_opt(dentry->d_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+	return ext4_xattr_set(dentry->d_inode, EXT4_XATTR_INDEX_USER,
+			      name, value, size, flags);
+}
+
+const struct xattr_handler ext4_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.list	= ext4_xattr_user_list,
+	.get	= ext4_xattr_user_get,
+	.set	= ext4_xattr_user_set,
+};