ext4: refactor __ext4_check_dir_entry() to accept start and size

The __ext4_check_dir_entry() function() is used to check whether the
de is over the block boundary.  Now with inline data, it could be
within the block boundary while exceeds the inode size.  So check this
function to check the overflow more precisely.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 9 insertions, 4 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index edb9f10..10da2d5 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -892,6 +892,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 					   EXT4_DIR_REC_LEN(0));
 	for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
 		if (ext4_check_dir_entry(dir, NULL, de, bh,
+				bh->b_data, bh->b_size,
 				(block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
 					 + ((char *)de - bh->b_data))) {
 			/* On error, skip the f_pos to the next block. */
@@ -1130,7 +1131,8 @@ static inline int search_dirblock(struct buffer_head *bh,
 		if ((char *) de + namelen <= dlimit &&
 		    ext4_match (namelen, name, de)) {
 			/* found a match - just to be sure, do a full check */
-			if (ext4_check_dir_entry(dir, NULL, de, bh, offset))
+			if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
+						 bh->b_size, offset))
 				return -1;
 			*res_dir = de;
 			return 1;
@@ -1643,7 +1645,8 @@ static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
 		de = (struct ext4_dir_entry_2 *)bh->b_data;
 		top = bh->b_data + (blocksize - csum_size) - reclen;
 		while ((char *) de <= top) {
-			if (ext4_check_dir_entry(dir, NULL, de, bh, offset))
+			if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
+						 bh->b_size, offset))
 				return -EIO;
 			if (ext4_match(namelen, name, de))
 				return -EEXIST;
@@ -2076,7 +2079,8 @@ static int ext4_delete_entry(handle_t *handle,
 	pde = NULL;
 	de = (struct ext4_dir_entry_2 *) bh->b_data;
 	while (i < bh->b_size - csum_size) {
-		if (ext4_check_dir_entry(dir, NULL, de, bh, i))
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+					 bh->b_data, bh->b_size, i))
 			return -EIO;
 		if (de == de_del)  {
 			BUFFER_TRACE(bh, "get_write_access");
@@ -2439,7 +2443,8 @@ static int empty_dir(struct inode *inode)
 			set_buffer_verified(bh);
 			de = (struct ext4_dir_entry_2 *) bh->b_data;
 		}
-		if (ext4_check_dir_entry(inode, NULL, de, bh, offset)) {
+		if (ext4_check_dir_entry(inode, NULL, de, bh,
+					 bh->b_data, bh->b_size, offset)) {
 			de = (struct ext4_dir_entry_2 *)(bh->b_data +
 							 sb->s_blocksize);
 			offset = (offset | (sb->s_blocksize - 1)) + 1;