ext4:fix file system corrupted when rmdir non empty directory with IO error

PATCH Applied Ye Bin 2 participants 2 messages Feb 28, 2022 – Mar 3, 2022 ext4 file system

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Ye Bin

author

2022-02-28 02:32 UTC #0 lore raw

PATCH v3 1/1 ext4:fix file system corrupted when rmdir non empty directory with IO error

We inject IO error when rmdir non empty direcory, then got issue as follows:
step1: mkfs.ext4 -F /dev/sda
step2: mount /dev/sda test
step3: cd test
step4: mkdir -p 1/2
step5: rmdir 1

	[  110.920551] ext4_empty_dir: inject fault
	[  110.921926] EXT4-fs warning (device sda): ext4_rmdir:3113: inode #12:
	comm rmdir: empty directory '1' has too many links (3)

step6: cd ..
step7: umount test
step8: fsck.ext4 -f /dev/sda
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Entry '..' in .../??? (13) has deleted/unused inode 12. Clear<y>? yes Pass 3: Checking directory connectivity
Unconnected directory inode 13 (...)
Connect to /lost+found<y>? yes
Pass 4: Checking reference counts
Inode 13 ref count is 3, should be 2. Fix<y>? yes
Pass 5: Checking group summary information

/dev/sda: ***** FILE SYSTEM WAS MODIFIED *****
/dev/sda: 12/131072 files (0.0% non-contiguous), 26157/524288 blocks

ext4_rmdir

	if (!ext4_empty_dir(inode))
		goto end_rmdir;
ext4_empty_dir
	bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
	if (IS_ERR(bh))
		return true;

Now if read directory block failed, 'ext4_empty_dir' will return true, assume directory is empty. Obviously, it will lead to above issue.
To solve this issue, if read directory block failed 'ext4_empty_dir' just return false. To avoid making things worse when file system is already corrupted, 'ext4_empty_dir' also return false.

Signed-off-by Ye Bin <[email protected]>

---
 fs/ext4/inline.c |  9 ++++-----
 fs/ext4/namei.c  | 10 +++++-----
 2 files changed, 9 insertions(+), 10 deletions(-)

fs/ext4/inline.c +4 -5

index e42941803605..9c076262770d 100644
@@ -1783,19 +1783,20 @@ bool empty_inline_dir(struct inode *dir, int *has_inline_data)
 	void *inline_pos;
 	unsigned int offset;
 	struct ext4_dir_entry_2 *de;
-	bool ret = true;
+	bool ret = false;
 
 	err = ext4_get_inode_loc(dir, &iloc);
 	if (err) {
 		EXT4_ERROR_INODE_ERR(dir, -err,
 				     "error %d getting inode %lu block",
 				     err, dir->i_ino);
-		return true;
+		return false;
 	}
 
 	down_read(&EXT4_I(dir)->xattr_sem);
 	if (!ext4_has_inline_data(dir)) {
 		*has_inline_data = 0;
+		ret = true;
 		goto out;
 	}

@@ -1804,7 +1805,6 @@ bool empty_inline_dir(struct inode *dir, int *has_inline_data)
 		ext4_warning(dir->i_sb,
 			     "bad inline directory (dir #%lu) - no `..'",
 			     dir->i_ino);
-		ret = true;
 		goto out;
 	}

@@ -1823,16 +1823,15 @@ bool empty_inline_dir(struct inode *dir, int *has_inline_data)
 				     dir->i_ino, le32_to_cpu(de->inode),
 				     le16_to_cpu(de->rec_len), de->name_len,
 				     inline_size);
-			ret = true;
 			goto out;
 		}
 		if (le32_to_cpu(de->inode)) {
-			ret = false;
 			goto out;
 		}
 		offset += ext4_rec_len_from_disk(de->rec_len, inline_size);
 	}
 
+	ret = true;
 out:
 	up_read(&EXT4_I(dir)->xattr_sem);
 	brelse(iloc.bh);

fs/ext4/namei.c +5 -5

index 8cf0a924a49b..39e223f7bf64 100644
@@ -2997,14 +2997,14 @@ bool ext4_empty_dir(struct inode *inode)
 	if (inode->i_size < ext4_dir_rec_len(1, NULL) +
 					ext4_dir_rec_len(2, NULL)) {
 		EXT4_ERROR_INODE(inode, "invalid size");
-		return true;
+		return false;
 	}
 	/* The first directory block must not be a hole,
 	 * so treat it as DIRENT_HTREE
 	 */
 	bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
 	if (IS_ERR(bh))
-		return true;
+		return false;
 
 	de = (struct ext4_dir_entry_2 *) bh->b_data;
 	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,

@@ -3012,7 +3012,7 @@ bool ext4_empty_dir(struct inode *inode)
 	    le32_to_cpu(de->inode) != inode->i_ino || strcmp(".", de->name)) {
 		ext4_warning_inode(inode, "directory missing '.'");
 		brelse(bh);
-		return true;
+		return false;
 	}
 	offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
 	de = ext4_next_entry(de, sb->s_blocksize);

@@ -3021,7 +3021,7 @@ bool ext4_empty_dir(struct inode *inode)
 	    le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
 		ext4_warning_inode(inode, "directory missing '..'");
 		brelse(bh);
-		return true;
+		return false;
 	}
 	offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
 	while (offset < inode->i_size) {

@@ -3035,7 +3035,7 @@ bool ext4_empty_dir(struct inode *inode)
 				continue;
 			}
 			if (IS_ERR(bh))
-				return true;
+				return false;
 		}
 		de = (struct ext4_dir_entry_2 *) (bh->b_data +
 					(offset & (sb->s_blocksize - 1)));

Signature · 1 line

2.31.1

Theodore Ts'o

maintainer Applied

2022-03-03 15:14 UTC #1 lore raw

Quoted 23 lines · Ye Bin

We inject IO error when rmdir non empty direcory, then got issue as follows:
step1: mkfs.ext4 -F /dev/sda
step2: mount /dev/sda test
step3: cd test
step4: mkdir -p 1/2
step5: rmdir 1
	[  110.920551] ext4_empty_dir: inject fault
	[  110.921926] EXT4-fs warning (device sda): ext4_rmdir:3113: inode #12:
	comm rmdir: empty directory '1' has too many links (3)
step6: cd ..
step7: umount test
step8: fsck.ext4 -f /dev/sda
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Entry '..' in .../??? (13) has deleted/unused inode 12. Clear<y>? yes Pass 3: Checking directory connectivity
Unconnected directory inode 13 (...)
Connect to /lost+found<y>? yes
Pass 4: Checking reference counts
Inode 13 ref count is 3, should be 2. Fix<y>? yes
Pass 5: Checking group summary information

Quoted 1 line

[...]

Applied, thanks!

[1/1] ext4:fix file system corrupted when rmdir non empty directory with IO error

      commit: 7aab5c84a0f6ec2290e2ba4a6b245178b1bf949a

Best regards,

Signature · 1 line

Theodore Ts'o <[email protected]>