[PATCH 6.1 344/473] f2fs: compress: dont allow unaligned truncation on released compress inode

Greg Kroah-Hartman
2024-06-06T14:17:36Z

From: Chao Yu <chao@kernel.org>

[ Upstream commit 29ed2b5dd521ce7c5d8466cd70bf0cc9d07afeee ]

f2fs image may be corrupted after below testcase:
- mkfs.f2fs -O extra_attr,compression -f /dev/vdb
- mount /dev/vdb /mnt/f2fs
- touch /mnt/f2fs/file
- f2fs_io setflags compression /mnt/f2fs/file
- dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=4
- f2fs_io release_cblocks /mnt/f2fs/file
- truncate -s 8192 /mnt/f2fs/file
- umount /mnt/f2fs
- fsck.f2fs /dev/vdb

[ASSERT] (fsck_chk_inode_blk:1256) --> ino: 0x5 has i_blocks: 0x00000002, but has 0x3 blocks
[FSCK] valid_block_count matching with CP [Fail] [0x4, 0x5]
[FSCK] other corrupted bugs [Fail]

The reason is: partial truncation assume compressed inode has reserved
blocks, after partial truncation, valid block count may change w/o
.i_blocks and .total_valid_block_count update, result in corruption.

This patch only allow cluster size aligned truncation on released
compress inode for fixing.

Fixes: c61404153eb6 ("f2fs: introduce FI_COMPRESS_RELEASED instead of using IMMUTABLE bit")
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/file.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 2b0f8408917bb..1d73582d1f63d 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -940,9 +940,14 @@ int f2fs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
ATTR_GID | ATTR_TIMES_SET))))
return -EPERM;

- if ((attr->ia_valid & ATTR_SIZE) &&
- !f2fs_is_compress_backend_ready(inode))
- return -EOPNOTSUPP;
+ if ((attr->ia_valid & ATTR_SIZE)) {
+ if (!f2fs_is_compress_backend_ready(inode))
+ return -EOPNOTSUPP;
+ if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED) &&
+ !IS_ALIGNED(attr->ia_size,
+ F2FS_BLK_TO_BYTES(F2FS_I(inode)->i_cluster_size)))
+ return -EINVAL;
+ }

err = setattr_prepare(mnt_userns, dentry, attr);
if (err)
--
2.43.0