When compressed file has blocks, f2fs_ioc_start_atomic_write will succeed,
but compressed flag will be remained in inode. If write partial compreseed
cluster and commit atomic write will cause data corruption.
This is the reproduction process:
Step 1:
create a compressed file ,write 64K data , call fsync(), then the blocks
are write as compressed cluster.
Step2:
iotcl(F2FS_IOC_START_ATOMIC_WRITE) --- this should be fail, but not.
write page 0 and page 3.
iotcl(F2FS_IOC_COMMIT_ATOMIC_WRITE) -- page 0 and 3 write as normal file,
Step3:
drop cache.
read page 0-4 -- Since page 0 has a valid block address, read as
non-compressed cluster, page 1 and 2 will be filled with compressed data
or zero.
The root cause is, after commit 7eab7a696827 ("f2fs: compress: remove
unneeded read when rewrite whole cluster"), in step 2, f2fs_write_begin()
only set target page dirty, and in f2fs_commit_inmem_pages(), we will write
partial raw pages into compressed cluster, result in corrupting compressed
cluster layout.
Fixes: 4c8ff7095bef ("f2fs: support data compression")
Fixes: 7eab7a696827 ("f2fs: compress: remove unneeded read when rewrite
whole cluster")
Signed-off-by: Fengnan Chang <[email protected]>
---
fs/f2fs/data.c | 2 +-
fs/f2fs/file.c | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b09f401f8960..5675af1b6916 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3363,7 +3363,7 @@ static int f2fs_write_begin(struct file *file, struct
address_space *mapping,
*fsdata = NULL;
- if (len == PAGE_SIZE)
+ if (len == PAGE_SIZE && !(f2fs_is_atomic_file(inode)))
goto repeat;
ret = f2fs_prepare_compress_overwrite(inode, pagep,
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index cfdc41f87f5d..2a07568ee61e 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2009,7 +2009,8 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
inode_lock(inode);
- f2fs_disable_compressed_file(inode);
+ if (!f2fs_disable_compressed_file(inode))
+ return -EINVAL;
if (f2fs_is_atomic_file(inode)) {
if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST))
--
2.32.0
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