Fixed MTP to work with TWRP

fs/ufs/dir.c

@@ -0,0 +1,662 @@
+/*
+ *  linux/fs/ufs/ufs_dir.c
+ *
+ * Copyright (C) 1996
+ * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
+ * Laboratory for Computer Science Research Computing Facility
+ * Rutgers, The State University of New Jersey
+ *
+ * swab support by Francois-Rene Rideau <fare@tunes.org> 19970406
+ *
+ * 4.4BSD (FreeBSD) support added on February 1st 1998 by
+ * Niels Kristian Bech Jensen <nkbj@image.dk> partially based
+ * on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>.
+ *
+ * Migration to usage of "page cache" on May 2006 by
+ * Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/swap.h>
+
+#include "ufs_fs.h"
+#include "ufs.h"
+#include "swab.h"
+#include "util.h"
+
+/*
+ * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure.
+ *
+ * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller.
+ */
+static inline int ufs_match(struct super_block *sb, int len,
+		const unsigned char *name, struct ufs_dir_entry *de)
+{
+	if (len != ufs_get_de_namlen(sb, de))
+		return 0;
+	if (!de->d_ino)
+		return 0;
+	return !memcmp(name, de->d_name, len);
+}
+
+static int ufs_commit_chunk(struct page *page, loff_t pos, unsigned len)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *dir = mapping->host;
+	int err = 0;
+
+	dir->i_version++;
+	block_write_end(NULL, mapping, pos, len, len, page, NULL);
+	if (pos+len > dir->i_size) {
+		i_size_write(dir, pos+len);
+		mark_inode_dirty(dir);
+	}
+	if (IS_DIRSYNC(dir))
+		err = write_one_page(page, 1);
+	else
+		unlock_page(page);
+	return err;
+}
+
+static inline void ufs_put_page(struct page *page)
+{
+	kunmap(page);
+	page_cache_release(page);
+}
+
+static inline unsigned long ufs_dir_pages(struct inode *inode)
+{
+	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
+}
+
+ino_t ufs_inode_by_name(struct inode *dir, const struct qstr *qstr)
+{
+	ino_t res = 0;
+	struct ufs_dir_entry *de;
+	struct page *page;
+	
+	de = ufs_find_entry(dir, qstr, &page);
+	if (de) {
+		res = fs32_to_cpu(dir->i_sb, de->d_ino);
+		ufs_put_page(page);
+	}
+	return res;
+}
+
+
+/* Releases the page */
+void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
+		  struct page *page, struct inode *inode)
+{
+	loff_t pos = page_offset(page) +
+			(char *) de - (char *) page_address(page);
+	unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen);
+	int err;
+
+	lock_page(page);
+	err = ufs_prepare_chunk(page, pos, len);
+	BUG_ON(err);
+
+	de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino);
+	ufs_set_de_type(dir->i_sb, de, inode->i_mode);
+
+	err = ufs_commit_chunk(page, pos, len);
+	ufs_put_page(page);
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+	mark_inode_dirty(dir);
+}
+
+
+static void ufs_check_page(struct page *page)
+{
+	struct inode *dir = page->mapping->host;
+	struct super_block *sb = dir->i_sb;
+	char *kaddr = page_address(page);
+	unsigned offs, rec_len;
+	unsigned limit = PAGE_CACHE_SIZE;
+	const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1;
+	struct ufs_dir_entry *p;
+	char *error;
+
+	if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
+		limit = dir->i_size & ~PAGE_CACHE_MASK;
+		if (limit & chunk_mask)
+			goto Ebadsize;
+		if (!limit)
+			goto out;
+	}
+	for (offs = 0; offs <= limit - UFS_DIR_REC_LEN(1); offs += rec_len) {
+		p = (struct ufs_dir_entry *)(kaddr + offs);
+		rec_len = fs16_to_cpu(sb, p->d_reclen);
+
+		if (rec_len < UFS_DIR_REC_LEN(1))
+			goto Eshort;
+		if (rec_len & 3)
+			goto Ealign;
+		if (rec_len < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p)))
+			goto Enamelen;
+		if (((offs + rec_len - 1) ^ offs) & ~chunk_mask)
+			goto Espan;
+		if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg *
+						  UFS_SB(sb)->s_uspi->s_ncg))
+			goto Einumber;
+	}
+	if (offs != limit)
+		goto Eend;
+out:
+	SetPageChecked(page);
+	return;
+
+	/* Too bad, we had an error */
+
+Ebadsize:
+	ufs_error(sb, "ufs_check_page",
+		  "size of directory #%lu is not a multiple of chunk size",
+		  dir->i_ino
+	);
+	goto fail;
+Eshort:
+	error = "rec_len is smaller than minimal";
+	goto bad_entry;
+Ealign:
+	error = "unaligned directory entry";
+	goto bad_entry;
+Enamelen:
+	error = "rec_len is too small for name_len";
+	goto bad_entry;
+Espan:
+	error = "directory entry across blocks";
+	goto bad_entry;
+Einumber:
+	error = "inode out of bounds";
+bad_entry:
+	ufs_error (sb, "ufs_check_page", "bad entry in directory #%lu: %s - "
+		   "offset=%lu, rec_len=%d, name_len=%d",
+		   dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
+		   rec_len, ufs_get_de_namlen(sb, p));
+	goto fail;
+Eend:
+	p = (struct ufs_dir_entry *)(kaddr + offs);
+	ufs_error(sb, __func__,
+		   "entry in directory #%lu spans the page boundary"
+		   "offset=%lu",
+		   dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs);
+fail:
+	SetPageChecked(page);
+	SetPageError(page);
+}
+
+static struct page *ufs_get_page(struct inode *dir, unsigned long n)
+{
+	struct address_space *mapping = dir->i_mapping;
+	struct page *page = read_mapping_page(mapping, n, NULL);
+	if (!IS_ERR(page)) {
+		kmap(page);
+		if (!PageChecked(page))
+			ufs_check_page(page);
+		if (PageError(page))
+			goto fail;
+	}
+	return page;
+
+fail:
+	ufs_put_page(page);
+	return ERR_PTR(-EIO);
+}
+
+/*
+ * Return the offset into page `page_nr' of the last valid
+ * byte in that page, plus one.
+ */
+static unsigned
+ufs_last_byte(struct inode *inode, unsigned long page_nr)
+{
+	unsigned last_byte = inode->i_size;
+
+	last_byte -= page_nr << PAGE_CACHE_SHIFT;
+	if (last_byte > PAGE_CACHE_SIZE)
+		last_byte = PAGE_CACHE_SIZE;
+	return last_byte;
+}
+
+static inline struct ufs_dir_entry *
+ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p)
+{
+	return (struct ufs_dir_entry *)((char *)p +
+					fs16_to_cpu(sb, p->d_reclen));
+}
+
+struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p)
+{
+	struct page *page = ufs_get_page(dir, 0);
+	struct ufs_dir_entry *de = NULL;
+
+	if (!IS_ERR(page)) {
+		de = ufs_next_entry(dir->i_sb,
+				    (struct ufs_dir_entry *)page_address(page));
+		*p = page;
+	}
+	return de;
+}
+
+/*
+ *	ufs_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the page in which the entry was found, and the entry itself
+ * (as a parameter - res_dir). Page is returned mapped and unlocked.
+ * Entry is guaranteed to be valid.
+ */
+struct ufs_dir_entry *ufs_find_entry(struct inode *dir, const struct qstr *qstr,
+				     struct page **res_page)
+{
+	struct super_block *sb = dir->i_sb;
+	const unsigned char *name = qstr->name;
+	int namelen = qstr->len;
+	unsigned reclen = UFS_DIR_REC_LEN(namelen);
+	unsigned long start, n;
+	unsigned long npages = ufs_dir_pages(dir);
+	struct page *page = NULL;
+	struct ufs_inode_info *ui = UFS_I(dir);
+	struct ufs_dir_entry *de;
+
+	UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen);
+
+	if (npages == 0 || namelen > UFS_MAXNAMLEN)
+		goto out;
+
+	/* OFFSET_CACHE */
+	*res_page = NULL;
+
+	start = ui->i_dir_start_lookup;
+
+	if (start >= npages)
+		start = 0;
+	n = start;
+	do {
+		char *kaddr;
+		page = ufs_get_page(dir, n);
+		if (!IS_ERR(page)) {
+			kaddr = page_address(page);
+			de = (struct ufs_dir_entry *) kaddr;
+			kaddr += ufs_last_byte(dir, n) - reclen;
+			while ((char *) de <= kaddr) {
+				if (de->d_reclen == 0) {
+					ufs_error(dir->i_sb, __func__,
+						  "zero-length directory entry");
+					ufs_put_page(page);
+					goto out;
+				}
+				if (ufs_match(sb, namelen, name, de))
+					goto found;
+				de = ufs_next_entry(sb, de);
+			}
+			ufs_put_page(page);
+		}
+		if (++n >= npages)
+			n = 0;
+	} while (n != start);
+out:
+	return NULL;
+
+found:
+	*res_page = page;
+	ui->i_dir_start_lookup = n;
+	return de;
+}
+
+/*
+ *	Parent is locked.
+ */
+int ufs_add_link(struct dentry *dentry, struct inode *inode)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+	const unsigned char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	struct super_block *sb = dir->i_sb;
+	unsigned reclen = UFS_DIR_REC_LEN(namelen);
+	const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
+	unsigned short rec_len, name_len;
+	struct page *page = NULL;
+	struct ufs_dir_entry *de;
+	unsigned long npages = ufs_dir_pages(dir);
+	unsigned long n;
+	char *kaddr;
+	loff_t pos;
+	int err;
+
+	UFSD("ENTER, name %s, namelen %u\n", name, namelen);
+
+	/*
+	 * We take care of directory expansion in the same loop.
+	 * This code plays outside i_size, so it locks the page
+	 * to protect that region.
+	 */
+	for (n = 0; n <= npages; n++) {
+		char *dir_end;
+
+		page = ufs_get_page(dir, n);
+		err = PTR_ERR(page);
+		if (IS_ERR(page))
+			goto out;
+		lock_page(page);
+		kaddr = page_address(page);
+		dir_end = kaddr + ufs_last_byte(dir, n);
+		de = (struct ufs_dir_entry *)kaddr;
+		kaddr += PAGE_CACHE_SIZE - reclen;
+		while ((char *)de <= kaddr) {
+			if ((char *)de == dir_end) {
+				/* We hit i_size */
+				name_len = 0;
+				rec_len = chunk_size;
+				de->d_reclen = cpu_to_fs16(sb, chunk_size);
+				de->d_ino = 0;
+				goto got_it;
+			}
+			if (de->d_reclen == 0) {
+				ufs_error(dir->i_sb, __func__,
+					  "zero-length directory entry");
+				err = -EIO;
+				goto out_unlock;
+			}
+			err = -EEXIST;
+			if (ufs_match(sb, namelen, name, de))
+				goto out_unlock;
+			name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de));
+			rec_len = fs16_to_cpu(sb, de->d_reclen);
+			if (!de->d_ino && rec_len >= reclen)
+				goto got_it;
+			if (rec_len >= name_len + reclen)
+				goto got_it;
+			de = (struct ufs_dir_entry *) ((char *) de + rec_len);
+		}
+		unlock_page(page);
+		ufs_put_page(page);
+	}
+	BUG();
+	return -EINVAL;
+
+got_it:
+	pos = page_offset(page) +
+			(char*)de - (char*)page_address(page);
+	err = ufs_prepare_chunk(page, pos, rec_len);
+	if (err)
+		goto out_unlock;
+	if (de->d_ino) {
+		struct ufs_dir_entry *de1 =
+			(struct ufs_dir_entry *) ((char *) de + name_len);
+		de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len);
+		de->d_reclen = cpu_to_fs16(sb, name_len);
+
+		de = de1;
+	}
+
+	ufs_set_de_namlen(sb, de, namelen);
+	memcpy(de->d_name, name, namelen + 1);
+	de->d_ino = cpu_to_fs32(sb, inode->i_ino);
+	ufs_set_de_type(sb, de, inode->i_mode);
+
+	err = ufs_commit_chunk(page, pos, rec_len);
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+
+	mark_inode_dirty(dir);
+	/* OFFSET_CACHE */
+out_put:
+	ufs_put_page(page);
+out:
+	return err;
+out_unlock:
+	unlock_page(page);
+	goto out_put;
+}
+
+static inline unsigned
+ufs_validate_entry(struct super_block *sb, char *base,
+		   unsigned offset, unsigned mask)
+{
+	struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset);
+	struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask));
+	while ((char*)p < (char*)de) {
+		if (p->d_reclen == 0)
+			break;
+		p = ufs_next_entry(sb, p);
+	}
+	return (char *)p - base;
+}
+
+
+/*
+ * This is blatantly stolen from ext2fs
+ */
+static int
+ufs_readdir(struct file *file, struct dir_context *ctx)
+{
+	loff_t pos = ctx->pos;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	unsigned int offset = pos & ~PAGE_CACHE_MASK;
+	unsigned long n = pos >> PAGE_CACHE_SHIFT;
+	unsigned long npages = ufs_dir_pages(inode);
+	unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
+	int need_revalidate = file->f_version != inode->i_version;
+	unsigned flags = UFS_SB(sb)->s_flags;
+
+	UFSD("BEGIN\n");
+
+	if (pos > inode->i_size - UFS_DIR_REC_LEN(1))
+		return 0;
+
+	for ( ; n < npages; n++, offset = 0) {
+		char *kaddr, *limit;
+		struct ufs_dir_entry *de;
+
+		struct page *page = ufs_get_page(inode, n);
+
+		if (IS_ERR(page)) {
+			ufs_error(sb, __func__,
+				  "bad page in #%lu",
+				  inode->i_ino);
+			ctx->pos += PAGE_CACHE_SIZE - offset;
+			return -EIO;
+		}
+		kaddr = page_address(page);
+		if (unlikely(need_revalidate)) {
+			if (offset) {
+				offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask);
+				ctx->pos = (n<<PAGE_CACHE_SHIFT) + offset;
+			}
+			file->f_version = inode->i_version;
+			need_revalidate = 0;
+		}
+		de = (struct ufs_dir_entry *)(kaddr+offset);
+		limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1);
+		for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) {
+			if (de->d_reclen == 0) {
+				ufs_error(sb, __func__,
+					"zero-length directory entry");
+				ufs_put_page(page);
+				return -EIO;
+			}
+			if (de->d_ino) {
+				unsigned char d_type = DT_UNKNOWN;
+
+				UFSD("filldir(%s,%u)\n", de->d_name,
+				      fs32_to_cpu(sb, de->d_ino));
+				UFSD("namlen %u\n", ufs_get_de_namlen(sb, de));
+
+				if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
+					d_type = de->d_u.d_44.d_type;
+
+				if (!dir_emit(ctx, de->d_name,
+					       ufs_get_de_namlen(sb, de),
+					       fs32_to_cpu(sb, de->d_ino),
+					       d_type)) {
+					ufs_put_page(page);
+					return 0;
+				}
+			}
+			ctx->pos += fs16_to_cpu(sb, de->d_reclen);
+		}
+		ufs_put_page(page);
+	}
+	return 0;
+}
+
+
+/*
+ * ufs_delete_entry deletes a directory entry by merging it with the
+ * previous entry.
+ */
+int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir,
+		     struct page * page)
+{
+	struct super_block *sb = inode->i_sb;
+	char *kaddr = page_address(page);
+	unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
+	unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen);
+	loff_t pos;
+	struct ufs_dir_entry *pde = NULL;
+	struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from);
+	int err;
+
+	UFSD("ENTER\n");
+
+	UFSD("ino %u, reclen %u, namlen %u, name %s\n",
+	      fs32_to_cpu(sb, de->d_ino),
+	      fs16_to_cpu(sb, de->d_reclen),
+	      ufs_get_de_namlen(sb, de), de->d_name);
+
+	while ((char*)de < (char*)dir) {
+		if (de->d_reclen == 0) {
+			ufs_error(inode->i_sb, __func__,
+				  "zero-length directory entry");
+			err = -EIO;
+			goto out;
+		}
+		pde = de;
+		de = ufs_next_entry(sb, de);
+	}
+	if (pde)
+		from = (char*)pde - (char*)page_address(page);
+
+	pos = page_offset(page) + from;
+	lock_page(page);
+	err = ufs_prepare_chunk(page, pos, to - from);
+	BUG_ON(err);
+	if (pde)
+		pde->d_reclen = cpu_to_fs16(sb, to - from);
+	dir->d_ino = 0;
+	err = ufs_commit_chunk(page, pos, to - from);
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
+	mark_inode_dirty(inode);
+out:
+	ufs_put_page(page);
+	UFSD("EXIT\n");
+	return err;
+}
+
+int ufs_make_empty(struct inode * inode, struct inode *dir)
+{
+	struct super_block * sb = dir->i_sb;
+	struct address_space *mapping = inode->i_mapping;
+	struct page *page = grab_cache_page(mapping, 0);
+	const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
+	struct ufs_dir_entry * de;
+	char *base;
+	int err;
+
+	if (!page)
+		return -ENOMEM;
+
+	err = ufs_prepare_chunk(page, 0, chunk_size);
+	if (err) {
+		unlock_page(page);
+		goto fail;
+	}
+
+	kmap(page);
+	base = (char*)page_address(page);
+	memset(base, 0, PAGE_CACHE_SIZE);
+
+	de = (struct ufs_dir_entry *) base;
+
+	de->d_ino = cpu_to_fs32(sb, inode->i_ino);
+	ufs_set_de_type(sb, de, inode->i_mode);
+	ufs_set_de_namlen(sb, de, 1);
+	de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1));
+	strcpy (de->d_name, ".");
+	de = (struct ufs_dir_entry *)
+		((char *)de + fs16_to_cpu(sb, de->d_reclen));
+	de->d_ino = cpu_to_fs32(sb, dir->i_ino);
+	ufs_set_de_type(sb, de, dir->i_mode);
+	de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1));
+	ufs_set_de_namlen(sb, de, 2);
+	strcpy (de->d_name, "..");
+	kunmap(page);
+
+	err = ufs_commit_chunk(page, 0, chunk_size);
+fail:
+	page_cache_release(page);
+	return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+int ufs_empty_dir(struct inode * inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct page *page = NULL;
+	unsigned long i, npages = ufs_dir_pages(inode);
+
+	for (i = 0; i < npages; i++) {
+		char *kaddr;
+		struct ufs_dir_entry *de;
+		page = ufs_get_page(inode, i);
+
+		if (IS_ERR(page))
+			continue;
+
+		kaddr = page_address(page);
+		de = (struct ufs_dir_entry *)kaddr;
+		kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1);
+
+		while ((char *)de <= kaddr) {
+			if (de->d_reclen == 0) {
+				ufs_error(inode->i_sb, __func__,
+					"zero-length directory entry: "
+					"kaddr=%p, de=%p\n", kaddr, de);
+				goto not_empty;
+			}
+			if (de->d_ino) {
+				u16 namelen=ufs_get_de_namlen(sb, de);
+				/* check for . and .. */
+				if (de->d_name[0] != '.')
+					goto not_empty;
+				if (namelen > 2)
+					goto not_empty;
+				if (namelen < 2) {
+					if (inode->i_ino !=
+					    fs32_to_cpu(sb, de->d_ino))
+						goto not_empty;
+				} else if (de->d_name[1] != '.')
+					goto not_empty;
+			}
+			de = ufs_next_entry(sb, de);
+		}
+		ufs_put_page(page);
+	}
+	return 1;
+
+not_empty:
+	ufs_put_page(page);
+	return 0;
+}
+
+const struct file_operations ufs_dir_operations = {
+	.read		= generic_read_dir,
+	.iterate	= ufs_readdir,
+	.fsync		= generic_file_fsync,
+	.llseek		= generic_file_llseek,
+};