Fixed MTP to work with TWRP

fs/efs/Kconfig

@@ -0,0 +1,14 @@
+config EFS_FS
+	tristate "EFS file system support (read only)"
+	depends on BLOCK
+	help
+	  EFS is an older file system used for non-ISO9660 CD-ROMs and hard
+	  disk partitions by SGI's IRIX operating system (IRIX 6.0 and newer
+	  uses the XFS file system for hard disk partitions however).
+
+	  This implementation only offers read-only access. If you don't know
+	  what all this is about, it's safe to say N. For more information
+	  about EFS see its home page at <http://aeschi.ch.eu.org/efs/>.
+
+	  To compile the EFS file system support as a module, choose M here: the
+	  module will be called efs.

fs/efs/Makefile

@@ -0,0 +1,7 @@
+#
+# Makefile for the linux efs-filesystem routines.
+#
+
+obj-$(CONFIG_EFS_FS) += efs.o
+
+efs-objs := super.o inode.o namei.o dir.o file.o symlink.o

fs/efs/dir.c

@@ -0,0 +1,103 @@
+/*
+ * dir.c
+ *
+ * Copyright (c) 1999 Al Smith
+ */
+
+#include <linux/buffer_head.h>
+#include "efs.h"
+
+static int efs_readdir(struct file *, struct dir_context *);
+
+const struct file_operations efs_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate	= efs_readdir,
+};
+
+const struct inode_operations efs_dir_inode_operations = {
+	.lookup		= efs_lookup,
+};
+
+static int efs_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	efs_block_t		block;
+	int			slot;
+
+	if (inode->i_size & (EFS_DIRBSIZE-1))
+		pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",
+			__func__);
+
+	/* work out where this entry can be found */
+	block = ctx->pos >> EFS_DIRBSIZE_BITS;
+
+	/* each block contains at most 256 slots */
+	slot  = ctx->pos & 0xff;
+
+	/* look at all blocks */
+	while (block < inode->i_blocks) {
+		struct efs_dir		*dirblock;
+		struct buffer_head *bh;
+
+		/* read the dir block */
+		bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
+
+		if (!bh) {
+			pr_err("%s(): failed to read dir block %d\n",
+			       __func__, block);
+			break;
+		}
+
+		dirblock = (struct efs_dir *) bh->b_data; 
+
+		if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
+			pr_err("%s(): invalid directory block\n", __func__);
+			brelse(bh);
+			break;
+		}
+
+		for (; slot < dirblock->slots; slot++) {
+			struct efs_dentry *dirslot;
+			efs_ino_t inodenum;
+			const char *nameptr;
+			int namelen;
+
+			if (dirblock->space[slot] == 0)
+				continue;
+
+			dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
+
+			inodenum = be32_to_cpu(dirslot->inode);
+			namelen  = dirslot->namelen;
+			nameptr  = dirslot->name;
+			pr_debug("%s(): block %d slot %d/%d: inode %u, name \"%s\", namelen %u\n",
+				 __func__, block, slot, dirblock->slots-1,
+				 inodenum, nameptr, namelen);
+			if (!namelen)
+				continue;
+			/* found the next entry */
+			ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
+
+			/* sanity check */
+			if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
+				pr_warn("directory entry %d exceeds directory block\n",
+					slot);
+				continue;
+			}
+
+			/* copy filename and data in dirslot */
+			if (!dir_emit(ctx, nameptr, namelen, inodenum, DT_UNKNOWN)) {
+				brelse(bh);
+				return 0;
+			}
+		}
+		brelse(bh);
+
+		slot = 0;
+		block++;
+	}
+	ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
+	return 0;
+}
+

fs/efs/efs.h

@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
+ * Portions derived from IRIX header files (c) 1988 Silicon Graphics
+ */
+#ifndef _EFS_EFS_H_
+#define _EFS_EFS_H_
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/fs.h>
+#include <asm/uaccess.h>
+
+#define EFS_VERSION "1.0a"
+
+static const char cprt[] = "EFS: "EFS_VERSION" - (c) 1999 Al Smith <Al.Smith@aeschi.ch.eu.org>";
+
+
+/* 1 block is 512 bytes */
+#define	EFS_BLOCKSIZE_BITS	9
+#define	EFS_BLOCKSIZE		(1 << EFS_BLOCKSIZE_BITS)
+
+typedef	int32_t		efs_block_t;
+typedef uint32_t	efs_ino_t;
+
+#define	EFS_DIRECTEXTENTS	12
+
+/*
+ * layout of an extent, in memory and on disk. 8 bytes exactly.
+ */
+typedef union extent_u {
+	unsigned char raw[8];
+	struct extent_s {
+		unsigned int	ex_magic:8;	/* magic # (zero) */
+		unsigned int	ex_bn:24;	/* basic block */
+		unsigned int	ex_length:8;	/* numblocks in this extent */
+		unsigned int	ex_offset:24;	/* logical offset into file */
+	} cooked;
+} efs_extent;
+
+typedef struct edevs {
+	__be16		odev;
+	__be32		ndev;
+} efs_devs;
+
+/*
+ * extent based filesystem inode as it appears on disk.  The efs inode
+ * is exactly 128 bytes long.
+ */
+struct	efs_dinode {
+	__be16		di_mode;	/* mode and type of file */
+	__be16		di_nlink;	/* number of links to file */
+	__be16		di_uid;		/* owner's user id */
+	__be16		di_gid;		/* owner's group id */
+	__be32		di_size;	/* number of bytes in file */
+	__be32		di_atime;	/* time last accessed */
+	__be32		di_mtime;	/* time last modified */
+	__be32		di_ctime;	/* time created */
+	__be32		di_gen;		/* generation number */
+	__be16		di_numextents;	/* # of extents */
+	u_char		di_version;	/* version of inode */
+	u_char		di_spare;	/* spare - used by AFS */
+	union di_addr {
+		efs_extent	di_extents[EFS_DIRECTEXTENTS];
+		efs_devs	di_dev;	/* device for IFCHR/IFBLK */
+	} di_u;
+};
+
+/* efs inode storage in memory */
+struct efs_inode_info {
+	int		numextents;
+	int		lastextent;
+
+	efs_extent	extents[EFS_DIRECTEXTENTS];
+	struct inode	vfs_inode;
+};
+
+#include <linux/efs_fs_sb.h>
+
+#define EFS_DIRBSIZE_BITS	EFS_BLOCKSIZE_BITS
+#define EFS_DIRBSIZE		(1 << EFS_DIRBSIZE_BITS)
+
+struct efs_dentry {
+	__be32		inode;
+	unsigned char	namelen;
+	char		name[3];
+};
+
+#define EFS_DENTSIZE	(sizeof(struct efs_dentry) - 3 + 1)
+#define EFS_MAXNAMELEN  ((1 << (sizeof(char) * 8)) - 1)
+
+#define EFS_DIRBLK_HEADERSIZE	4
+#define EFS_DIRBLK_MAGIC	0xbeef	/* moo */
+
+struct efs_dir {
+	__be16	magic;
+	unsigned char	firstused;
+	unsigned char	slots;
+
+	unsigned char	space[EFS_DIRBSIZE - EFS_DIRBLK_HEADERSIZE];
+};
+
+#define EFS_MAXENTS \
+	((EFS_DIRBSIZE - EFS_DIRBLK_HEADERSIZE) / \
+	 (EFS_DENTSIZE + sizeof(char)))
+
+#define EFS_SLOTAT(dir, slot) EFS_REALOFF((dir)->space[slot])
+
+#define EFS_REALOFF(offset) ((offset << 1))
+
+
+static inline struct efs_inode_info *INODE_INFO(struct inode *inode)
+{
+	return container_of(inode, struct efs_inode_info, vfs_inode);
+}
+
+static inline struct efs_sb_info *SUPER_INFO(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+struct statfs;
+struct fid;
+
+extern const struct inode_operations efs_dir_inode_operations;
+extern const struct file_operations efs_dir_operations;
+extern const struct address_space_operations efs_symlink_aops;
+
+extern struct inode *efs_iget(struct super_block *, unsigned long);
+extern efs_block_t efs_map_block(struct inode *, efs_block_t);
+extern int efs_get_block(struct inode *, sector_t, struct buffer_head *, int);
+
+extern struct dentry *efs_lookup(struct inode *, struct dentry *, unsigned int);
+extern struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type);
+extern struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type);
+extern struct dentry *efs_get_parent(struct dentry *);
+extern int efs_bmap(struct inode *, int);
+
+#endif /* _EFS_EFS_H_ */

fs/efs/file.c

@@ -0,0 +1,56 @@
+/*
+ * file.c
+ *
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
+ */
+
+#include <linux/buffer_head.h>
+#include "efs.h"
+
+int efs_get_block(struct inode *inode, sector_t iblock,
+		  struct buffer_head *bh_result, int create)
+{
+	int error = -EROFS;
+	long phys;
+
+	if (create)
+		return error;
+	if (iblock >= inode->i_blocks) {
+#ifdef DEBUG
+		/*
+		 * i have no idea why this happens as often as it does
+		 */
+		pr_warn("%s(): block %d >= %ld (filesize %ld)\n",
+			__func__, block, inode->i_blocks, inode->i_size);
+#endif
+		return 0;
+	}
+	phys = efs_map_block(inode, iblock);
+	if (phys)
+		map_bh(bh_result, inode->i_sb, phys);
+	return 0;
+}
+
+int efs_bmap(struct inode *inode, efs_block_t block) {
+
+	if (block < 0) {
+		pr_warn("%s(): block < 0\n", __func__);
+		return 0;
+	}
+
+	/* are we about to read past the end of a file ? */
+	if (!(block < inode->i_blocks)) {
+#ifdef DEBUG
+		/*
+		 * i have no idea why this happens as often as it does
+		 */
+		pr_warn("%s(): block %d >= %ld (filesize %ld)\n",
+			__func__, block, inode->i_blocks, inode->i_size);
+#endif
+		return 0;
+	}
+
+	return efs_map_block(inode, block);
+}

fs/efs/inode.c

@@ -0,0 +1,311 @@
+/*
+ * inode.c
+ *
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang,
+ *              and from work (c) 1998 Mike Shaver.
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include "efs.h"
+#include <linux/efs_fs_sb.h>
+
+static int efs_readpage(struct file *file, struct page *page)
+{
+	return block_read_full_page(page,efs_get_block);
+}
+static sector_t _efs_bmap(struct address_space *mapping, sector_t block)
+{
+	return generic_block_bmap(mapping,block,efs_get_block);
+}
+static const struct address_space_operations efs_aops = {
+	.readpage = efs_readpage,
+	.bmap = _efs_bmap
+};
+
+static inline void extent_copy(efs_extent *src, efs_extent *dst) {
+	/*
+	 * this is slightly evil. it doesn't just copy
+	 * efs_extent from src to dst, it also mangles
+	 * the bits so that dst ends up in cpu byte-order.
+	 */
+
+	dst->cooked.ex_magic  =  (unsigned int) src->raw[0];
+	dst->cooked.ex_bn     = ((unsigned int) src->raw[1] << 16) |
+				((unsigned int) src->raw[2] <<  8) |
+				((unsigned int) src->raw[3] <<  0);
+	dst->cooked.ex_length =  (unsigned int) src->raw[4];
+	dst->cooked.ex_offset = ((unsigned int) src->raw[5] << 16) |
+				((unsigned int) src->raw[6] <<  8) |
+				((unsigned int) src->raw[7] <<  0);
+	return;
+}
+
+struct inode *efs_iget(struct super_block *super, unsigned long ino)
+{
+	int i, inode_index;
+	dev_t device;
+	u32 rdev;
+	struct buffer_head *bh;
+	struct efs_sb_info    *sb = SUPER_INFO(super);
+	struct efs_inode_info *in;
+	efs_block_t block, offset;
+	struct efs_dinode *efs_inode;
+	struct inode *inode;
+
+	inode = iget_locked(super, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	in = INODE_INFO(inode);
+
+	/*
+	** EFS layout:
+	**
+	** |   cylinder group    |   cylinder group    |   cylinder group ..etc
+	** |inodes|data          |inodes|data          |inodes|data       ..etc
+	**
+	** work out the inode block index, (considering initially that the
+	** inodes are stored as consecutive blocks). then work out the block
+	** number of that inode given the above layout, and finally the
+	** offset of the inode within that block.
+	*/
+
+	inode_index = inode->i_ino /
+		(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
+
+	block = sb->fs_start + sb->first_block + 
+		(sb->group_size * (inode_index / sb->inode_blocks)) +
+		(inode_index % sb->inode_blocks);
+
+	offset = (inode->i_ino %
+			(EFS_BLOCKSIZE / sizeof(struct efs_dinode))) *
+		sizeof(struct efs_dinode);
+
+	bh = sb_bread(inode->i_sb, block);
+	if (!bh) {
+		pr_warn("%s() failed at block %d\n", __func__, block);
+		goto read_inode_error;
+	}
+
+	efs_inode = (struct efs_dinode *) (bh->b_data + offset);
+    
+	inode->i_mode  = be16_to_cpu(efs_inode->di_mode);
+	set_nlink(inode, be16_to_cpu(efs_inode->di_nlink));
+	i_uid_write(inode, (uid_t)be16_to_cpu(efs_inode->di_uid));
+	i_gid_write(inode, (gid_t)be16_to_cpu(efs_inode->di_gid));
+	inode->i_size  = be32_to_cpu(efs_inode->di_size);
+	inode->i_atime.tv_sec = be32_to_cpu(efs_inode->di_atime);
+	inode->i_mtime.tv_sec = be32_to_cpu(efs_inode->di_mtime);
+	inode->i_ctime.tv_sec = be32_to_cpu(efs_inode->di_ctime);
+	inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
+
+	/* this is the number of blocks in the file */
+	if (inode->i_size == 0) {
+		inode->i_blocks = 0;
+	} else {
+		inode->i_blocks = ((inode->i_size - 1) >> EFS_BLOCKSIZE_BITS) + 1;
+	}
+
+	rdev = be16_to_cpu(efs_inode->di_u.di_dev.odev);
+	if (rdev == 0xffff) {
+		rdev = be32_to_cpu(efs_inode->di_u.di_dev.ndev);
+		if (sysv_major(rdev) > 0xfff)
+			device = 0;
+		else
+			device = MKDEV(sysv_major(rdev), sysv_minor(rdev));
+	} else
+		device = old_decode_dev(rdev);
+
+	/* get the number of extents for this object */
+	in->numextents = be16_to_cpu(efs_inode->di_numextents);
+	in->lastextent = 0;
+
+	/* copy the extents contained within the inode to memory */
+	for(i = 0; i < EFS_DIRECTEXTENTS; i++) {
+		extent_copy(&(efs_inode->di_u.di_extents[i]), &(in->extents[i]));
+		if (i < in->numextents && in->extents[i].cooked.ex_magic != 0) {
+			pr_warn("extent %d has bad magic number in inode %lu\n",
+				i, inode->i_ino);
+			brelse(bh);
+			goto read_inode_error;
+		}
+	}
+
+	brelse(bh);
+	pr_debug("efs_iget(): inode %lu, extents %d, mode %o\n",
+		 inode->i_ino, in->numextents, inode->i_mode);
+	switch (inode->i_mode & S_IFMT) {
+		case S_IFDIR: 
+			inode->i_op = &efs_dir_inode_operations; 
+			inode->i_fop = &efs_dir_operations; 
+			break;
+		case S_IFREG:
+			inode->i_fop = &generic_ro_fops;
+			inode->i_data.a_ops = &efs_aops;
+			break;
+		case S_IFLNK:
+			inode->i_op = &page_symlink_inode_operations;
+			inode->i_data.a_ops = &efs_symlink_aops;
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
+		case S_IFIFO:
+			init_special_inode(inode, inode->i_mode, device);
+			break;
+		default:
+			pr_warn("unsupported inode mode %o\n", inode->i_mode);
+			goto read_inode_error;
+			break;
+	}
+
+	unlock_new_inode(inode);
+	return inode;
+        
+read_inode_error:
+	pr_warn("failed to read inode %lu\n", inode->i_ino);
+	iget_failed(inode);
+	return ERR_PTR(-EIO);
+}
+
+static inline efs_block_t
+efs_extent_check(efs_extent *ptr, efs_block_t block, struct efs_sb_info *sb) {
+	efs_block_t start;
+	efs_block_t length;
+	efs_block_t offset;
+
+	/*
+	 * given an extent and a logical block within a file,
+	 * can this block be found within this extent ?
+	 */
+	start  = ptr->cooked.ex_bn;
+	length = ptr->cooked.ex_length;
+	offset = ptr->cooked.ex_offset;
+
+	if ((block >= offset) && (block < offset+length)) {
+		return(sb->fs_start + start + block - offset);
+	} else {
+		return 0;
+	}
+}
+
+efs_block_t efs_map_block(struct inode *inode, efs_block_t block) {
+	struct efs_sb_info    *sb = SUPER_INFO(inode->i_sb);
+	struct efs_inode_info *in = INODE_INFO(inode);
+	struct buffer_head    *bh = NULL;
+
+	int cur, last, first = 1;
+	int ibase, ioffset, dirext, direxts, indext, indexts;
+	efs_block_t iblock, result = 0, lastblock = 0;
+	efs_extent ext, *exts;
+
+	last = in->lastextent;
+
+	if (in->numextents <= EFS_DIRECTEXTENTS) {
+		/* first check the last extent we returned */
+		if ((result = efs_extent_check(&in->extents[last], block, sb)))
+			return result;
+    
+		/* if we only have one extent then nothing can be found */
+		if (in->numextents == 1) {
+			pr_err("%s() failed to map (1 extent)\n", __func__);
+			return 0;
+		}
+
+		direxts = in->numextents;
+
+		/*
+		 * check the stored extents in the inode
+		 * start with next extent and check forwards
+		 */
+		for(dirext = 1; dirext < direxts; dirext++) {
+			cur = (last + dirext) % in->numextents;
+			if ((result = efs_extent_check(&in->extents[cur], block, sb))) {
+				in->lastextent = cur;
+				return result;
+			}
+		}
+
+		pr_err("%s() failed to map block %u (dir)\n", __func__, block);
+		return 0;
+	}
+
+	pr_debug("%s(): indirect search for logical block %u\n",
+		 __func__, block);
+	direxts = in->extents[0].cooked.ex_offset;
+	indexts = in->numextents;
+
+	for(indext = 0; indext < indexts; indext++) {
+		cur = (last + indext) % indexts;
+
+		/*
+		 * work out which direct extent contains `cur'.
+		 *
+		 * also compute ibase: i.e. the number of the first
+		 * indirect extent contained within direct extent `cur'.
+		 *
+		 */
+		ibase = 0;
+		for(dirext = 0; cur < ibase && dirext < direxts; dirext++) {
+			ibase += in->extents[dirext].cooked.ex_length *
+				(EFS_BLOCKSIZE / sizeof(efs_extent));
+		}
+
+		if (dirext == direxts) {
+			/* should never happen */
+			pr_err("couldn't find direct extent for indirect extent %d (block %u)\n",
+			       cur, block);
+			if (bh) brelse(bh);
+			return 0;
+		}
+		
+		/* work out block number and offset of this indirect extent */
+		iblock = sb->fs_start + in->extents[dirext].cooked.ex_bn +
+			(cur - ibase) /
+			(EFS_BLOCKSIZE / sizeof(efs_extent));
+		ioffset = (cur - ibase) %
+			(EFS_BLOCKSIZE / sizeof(efs_extent));
+
+		if (first || lastblock != iblock) {
+			if (bh) brelse(bh);
+
+			bh = sb_bread(inode->i_sb, iblock);
+			if (!bh) {
+				pr_err("%s() failed at block %d\n",
+				       __func__, iblock);
+				return 0;
+			}
+			pr_debug("%s(): read indirect extent block %d\n",
+				 __func__, iblock);
+			first = 0;
+			lastblock = iblock;
+		}
+
+		exts = (efs_extent *) bh->b_data;
+
+		extent_copy(&(exts[ioffset]), &ext);
+
+		if (ext.cooked.ex_magic != 0) {
+			pr_err("extent %d has bad magic number in block %d\n",
+			       cur, iblock);
+			if (bh) brelse(bh);
+			return 0;
+		}
+
+		if ((result = efs_extent_check(&ext, block, sb))) {
+			if (bh) brelse(bh);
+			in->lastextent = cur;
+			return result;
+		}
+	}
+	if (bh) brelse(bh);
+	pr_err("%s() failed to map block %u (indir)\n", __func__, block);
+	return 0;
+}  
+
+MODULE_LICENSE("GPL");

fs/efs/namei.c

@@ -0,0 +1,119 @@
+/*
+ * namei.c
+ *
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/string.h>
+#include <linux/exportfs.h>
+#include "efs.h"
+
+
+static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len)
+{
+	struct buffer_head *bh;
+
+	int			slot, namelen;
+	char			*nameptr;
+	struct efs_dir		*dirblock;
+	struct efs_dentry	*dirslot;
+	efs_ino_t		inodenum;
+	efs_block_t		block;
+ 
+	if (inode->i_size & (EFS_DIRBSIZE-1))
+		pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",
+			__func__);
+
+	for(block = 0; block < inode->i_blocks; block++) {
+
+		bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
+		if (!bh) {
+			pr_err("%s(): failed to read dir block %d\n",
+			       __func__, block);
+			return 0;
+		}
+    
+		dirblock = (struct efs_dir *) bh->b_data;
+
+		if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
+			pr_err("%s(): invalid directory block\n", __func__);
+			brelse(bh);
+			return 0;
+		}
+
+		for (slot = 0; slot < dirblock->slots; slot++) {
+			dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
+
+			namelen  = dirslot->namelen;
+			nameptr  = dirslot->name;
+
+			if ((namelen == len) && (!memcmp(name, nameptr, len))) {
+				inodenum = be32_to_cpu(dirslot->inode);
+				brelse(bh);
+				return inodenum;
+			}
+		}
+		brelse(bh);
+	}
+	return 0;
+}
+
+struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	efs_ino_t inodenum;
+	struct inode *inode = NULL;
+
+	inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
+	if (inodenum)
+		inode = efs_iget(dir->i_sb, inodenum);
+
+	return d_splice_alias(inode, dentry);
+}
+
+static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
+		u32 generation)
+{
+	struct inode *inode;
+
+	if (ino == 0)
+		return ERR_PTR(-ESTALE);
+	inode = efs_iget(sb, ino);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
+	if (generation && inode->i_generation != generation) {
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+
+	return inode;
+}
+
+struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    efs_nfs_get_inode);
+}
+
+struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    efs_nfs_get_inode);
+}
+
+struct dentry *efs_get_parent(struct dentry *child)
+{
+	struct dentry *parent = ERR_PTR(-ENOENT);
+	efs_ino_t ino;
+
+	ino = efs_find_entry(child->d_inode, "..", 2);
+	if (ino)
+		parent = d_obtain_alias(efs_iget(child->d_inode->i_sb, ino));
+
+	return parent;
+}

fs/efs/super.c

@@ -0,0 +1,353 @@
+/*
+ * super.c
+ *
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/exportfs.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+#include <linux/vfs.h>
+
+#include "efs.h"
+#include <linux/efs_vh.h>
+#include <linux/efs_fs_sb.h>
+
+static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
+static int efs_fill_super(struct super_block *s, void *d, int silent);
+
+static struct dentry *efs_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_bdev(fs_type, flags, dev_name, data, efs_fill_super);
+}
+
+static void efs_kill_sb(struct super_block *s)
+{
+	struct efs_sb_info *sbi = SUPER_INFO(s);
+	kill_block_super(s);
+	kfree(sbi);
+}
+
+static struct file_system_type efs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "efs",
+	.mount		= efs_mount,
+	.kill_sb	= efs_kill_sb,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("efs");
+
+static struct pt_types sgi_pt_types[] = {
+	{0x00,		"SGI vh"},
+	{0x01,		"SGI trkrepl"},
+	{0x02,		"SGI secrepl"},
+	{0x03,		"SGI raw"},
+	{0x04,		"SGI bsd"},
+	{SGI_SYSV,	"SGI sysv"},
+	{0x06,		"SGI vol"},
+	{SGI_EFS,	"SGI efs"},
+	{0x08,		"SGI lv"},
+	{0x09,		"SGI rlv"},
+	{0x0A,		"SGI xfs"},
+	{0x0B,		"SGI xfslog"},
+	{0x0C,		"SGI xlv"},
+	{0x82,		"Linux swap"},
+	{0x83,		"Linux native"},
+	{0,		NULL}
+};
+
+
+static struct kmem_cache * efs_inode_cachep;
+
+static struct inode *efs_alloc_inode(struct super_block *sb)
+{
+	struct efs_inode_info *ei;
+	ei = (struct efs_inode_info *)kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
+	if (!ei)
+		return NULL;
+	return &ei->vfs_inode;
+}
+
+static void efs_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
+}
+
+static void efs_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, efs_i_callback);
+}
+
+static void init_once(void *foo)
+{
+	struct efs_inode_info *ei = (struct efs_inode_info *) foo;
+
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int __init init_inodecache(void)
+{
+	efs_inode_cachep = kmem_cache_create("efs_inode_cache",
+				sizeof(struct efs_inode_info),
+				0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
+				init_once);
+	if (efs_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(efs_inode_cachep);
+}
+
+static int efs_remount(struct super_block *sb, int *flags, char *data)
+{
+	sync_filesystem(sb);
+	*flags |= MS_RDONLY;
+	return 0;
+}
+
+static const struct super_operations efs_superblock_operations = {
+	.alloc_inode	= efs_alloc_inode,
+	.destroy_inode	= efs_destroy_inode,
+	.statfs		= efs_statfs,
+	.remount_fs	= efs_remount,
+};
+
+static const struct export_operations efs_export_ops = {
+	.fh_to_dentry	= efs_fh_to_dentry,
+	.fh_to_parent	= efs_fh_to_parent,
+	.get_parent	= efs_get_parent,
+};
+
+static int __init init_efs_fs(void) {
+	int err;
+	pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
+	err = init_inodecache();
+	if (err)
+		goto out1;
+	err = register_filesystem(&efs_fs_type);
+	if (err)
+		goto out;
+	return 0;
+out:
+	destroy_inodecache();
+out1:
+	return err;
+}
+
+static void __exit exit_efs_fs(void) {
+	unregister_filesystem(&efs_fs_type);
+	destroy_inodecache();
+}
+
+module_init(init_efs_fs)
+module_exit(exit_efs_fs)
+
+static efs_block_t efs_validate_vh(struct volume_header *vh) {
+	int		i;
+	__be32		cs, *ui;
+	int		csum;
+	efs_block_t	sblock = 0; /* shuts up gcc */
+	struct pt_types	*pt_entry;
+	int		pt_type, slice = -1;
+
+	if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
+		/*
+		 * assume that we're dealing with a partition and allow
+		 * read_super() to try and detect a valid superblock
+		 * on the next block.
+		 */
+		return 0;
+	}
+
+	ui = ((__be32 *) (vh + 1)) - 1;
+	for(csum = 0; ui >= ((__be32 *) vh);) {
+		cs = *ui--;
+		csum += be32_to_cpu(cs);
+	}
+	if (csum) {
+		pr_warn("SGI disklabel: checksum bad, label corrupted\n");
+		return 0;
+	}
+
+#ifdef DEBUG
+	pr_debug("bf: \"%16s\"\n", vh->vh_bootfile);
+
+	for(i = 0; i < NVDIR; i++) {
+		int	j;
+		char	name[VDNAMESIZE+1];
+
+		for(j = 0; j < VDNAMESIZE; j++) {
+			name[j] = vh->vh_vd[i].vd_name[j];
+		}
+		name[j] = (char) 0;
+
+		if (name[0]) {
+			pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n",
+				name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
+				(int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
+		}
+	}
+#endif
+
+	for(i = 0; i < NPARTAB; i++) {
+		pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
+		for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
+			if (pt_type == pt_entry->pt_type) break;
+		}
+#ifdef DEBUG
+		if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
+			pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
+				 i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
+				 (int)be32_to_cpu(vh->vh_pt[i].pt_nblks),
+				 pt_type, (pt_entry->pt_name) ?
+				 pt_entry->pt_name : "unknown");
+		}
+#endif
+		if (IS_EFS(pt_type)) {
+			sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
+			slice = i;
+		}
+	}
+
+	if (slice == -1) {
+		pr_notice("partition table contained no EFS partitions\n");
+#ifdef DEBUG
+	} else {
+		pr_info("using slice %d (type %s, offset 0x%x)\n", slice,
+			(pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
+			sblock);
+#endif
+	}
+	return sblock;
+}
+
+static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
+
+	if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
+		return -1;
+
+	sb->fs_magic     = be32_to_cpu(super->fs_magic);
+	sb->total_blocks = be32_to_cpu(super->fs_size);
+	sb->first_block  = be32_to_cpu(super->fs_firstcg);
+	sb->group_size   = be32_to_cpu(super->fs_cgfsize);
+	sb->data_free    = be32_to_cpu(super->fs_tfree);
+	sb->inode_free   = be32_to_cpu(super->fs_tinode);
+	sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
+	sb->total_groups = be16_to_cpu(super->fs_ncg);
+    
+	return 0;    
+}
+
+static int efs_fill_super(struct super_block *s, void *d, int silent)
+{
+	struct efs_sb_info *sb;
+	struct buffer_head *bh;
+	struct inode *root;
+
+ 	sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
+	if (!sb)
+		return -ENOMEM;
+	s->s_fs_info = sb;
+ 
+	s->s_magic		= EFS_SUPER_MAGIC;
+	if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
+		pr_err("device does not support %d byte blocks\n",
+			EFS_BLOCKSIZE);
+		return -EINVAL;
+	}
+  
+	/* read the vh (volume header) block */
+	bh = sb_bread(s, 0);
+
+	if (!bh) {
+		pr_err("cannot read volume header\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * if this returns zero then we didn't find any partition table.
+	 * this isn't (yet) an error - just assume for the moment that
+	 * the device is valid and go on to search for a superblock.
+	 */
+	sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
+	brelse(bh);
+
+	if (sb->fs_start == -1) {
+		return -EINVAL;
+	}
+
+	bh = sb_bread(s, sb->fs_start + EFS_SUPER);
+	if (!bh) {
+		pr_err("cannot read superblock\n");
+		return -EINVAL;
+	}
+		
+	if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
+#ifdef DEBUG
+		pr_warn("invalid superblock at block %u\n",
+			sb->fs_start + EFS_SUPER);
+#endif
+		brelse(bh);
+		return -EINVAL;
+	}
+	brelse(bh);
+
+	if (!(s->s_flags & MS_RDONLY)) {
+#ifdef DEBUG
+		pr_info("forcing read-only mode\n");
+#endif
+		s->s_flags |= MS_RDONLY;
+	}
+	s->s_op   = &efs_superblock_operations;
+	s->s_export_op = &efs_export_ops;
+	root = efs_iget(s, EFS_ROOTINODE);
+	if (IS_ERR(root)) {
+		pr_err("get root inode failed\n");
+		return PTR_ERR(root);
+	}
+
+	s->s_root = d_make_root(root);
+	if (!(s->s_root)) {
+		pr_err("get root dentry failed\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
+	struct super_block *sb = dentry->d_sb;
+	struct efs_sb_info *sbi = SUPER_INFO(sb);
+	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	buf->f_type    = EFS_SUPER_MAGIC;	/* efs magic number */
+	buf->f_bsize   = EFS_BLOCKSIZE;		/* blocksize */
+	buf->f_blocks  = sbi->total_groups *	/* total data blocks */
+			(sbi->group_size - sbi->inode_blocks);
+	buf->f_bfree   = sbi->data_free;	/* free data blocks */
+	buf->f_bavail  = sbi->data_free;	/* free blocks for non-root */
+	buf->f_files   = sbi->total_groups *	/* total inodes */
+			sbi->inode_blocks *
+			(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
+	buf->f_ffree   = sbi->inode_free;	/* free inodes */
+	buf->f_fsid.val[0] = (u32)id;
+	buf->f_fsid.val[1] = (u32)(id >> 32);
+	buf->f_namelen = EFS_MAXNAMELEN;	/* max filename length */
+
+	return 0;
+}
+

fs/efs/symlink.c

@@ -0,0 +1,54 @@
+/*
+ * symlink.c
+ *
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
+ */
+
+#include <linux/string.h>
+#include <linux/pagemap.h>
+#include <linux/buffer_head.h>
+#include "efs.h"
+
+static int efs_symlink_readpage(struct file *file, struct page *page)
+{
+	char *link = kmap(page);
+	struct buffer_head * bh;
+	struct inode * inode = page->mapping->host;
+	efs_block_t size = inode->i_size;
+	int err;
+  
+	err = -ENAMETOOLONG;
+	if (size > 2 * EFS_BLOCKSIZE)
+		goto fail;
+  
+	/* read first 512 bytes of link target */
+	err = -EIO;
+	bh = sb_bread(inode->i_sb, efs_bmap(inode, 0));
+	if (!bh)
+		goto fail;
+	memcpy(link, bh->b_data, (size > EFS_BLOCKSIZE) ? EFS_BLOCKSIZE : size);
+	brelse(bh);
+	if (size > EFS_BLOCKSIZE) {
+		bh = sb_bread(inode->i_sb, efs_bmap(inode, 1));
+		if (!bh)
+			goto fail;
+		memcpy(link + EFS_BLOCKSIZE, bh->b_data, size - EFS_BLOCKSIZE);
+		brelse(bh);
+	}
+	link[size] = '\0';
+	SetPageUptodate(page);
+	kunmap(page);
+	unlock_page(page);
+	return 0;
+fail:
+	SetPageError(page);
+	kunmap(page);
+	unlock_page(page);
+	return err;
+}
+
+const struct address_space_operations efs_symlink_aops = {
+	.readpage	= efs_symlink_readpage
+};