[PATCH v2] f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i_sem

[PATCH v2] f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i_sem

[Chao Yu]

- f2fs_disable_compressed_file
  - check inode_has_data
					- f2fs_file_mmap
					- mkwrite
					 - f2fs_get_block_locked
					 : update metadata in compressed
					   inode's disk layout
  - fi->i_flags &= ~F2FS_COMPR_FL
  - clear_inode_flag(inode, FI_COMPRESSED_FILE);

we should use i_sem lock to prevent above race case.

Fixes: 4c8ff7095bef ("f2fs: support data compression")
Signed-off-by: Chao Yu <chao@kernel.org>
---
v2:
- remove unneeded i_size check pointed out by Jaegeuk.
 fs/f2fs/f2fs.h | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4481f68d6418..c6655fbdeb5e 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4409,15 +4409,24 @@ static inline bool f2fs_disable_compressed_file(struct inode *inode)
 {
 	struct f2fs_inode_info *fi = F2FS_I(inode);
 
-	if (!f2fs_compressed_file(inode))
+	f2fs_down_write(&F2FS_I(inode)->i_sem);
+
+	if (!f2fs_compressed_file(inode)) {
+		f2fs_up_write(&F2FS_I(inode)->i_sem);
 		return true;
-	if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode))
+	}
+	if (f2fs_is_mmap_file(inode) ||
+		(S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode))) {
+		f2fs_up_write(&F2FS_I(inode)->i_sem);
 		return false;
+	}
 
 	fi->i_flags &= ~F2FS_COMPR_FL;
 	stat_dec_compr_inode(inode);
 	clear_inode_flag(inode, FI_COMPRESSED_FILE);
 	f2fs_mark_inode_dirty_sync(inode, true);
+
+	f2fs_up_write(&F2FS_I(inode)->i_sem);
 	return true;
 }
 
-- 
2.40.1

Re: [f2fs-dev] [PATCH v2] f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i_sem

[patchwork-bot+f2fs]

Hello:

This patch was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <jaegeuk@kernel.org>:

On Mon, 22 Jan 2024 10:23:13 +0800 you wrote:
> - f2fs_disable_compressed_file
>   - check inode_has_data
> 					- f2fs_file_mmap
> 					- mkwrite
> 					 - f2fs_get_block_locked
> 					 : update metadata in compressed
> 					   inode's disk layout
>   - fi->i_flags &= ~F2FS_COMPR_FL
>   - clear_inode_flag(inode, FI_COMPRESSED_FILE);
> 
> [...]

Here is the summary with links:
  - [f2fs-dev,v2] f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i_sem
    https://git.kernel.org/jaegeuk/f2fs/c/9f100ecdedc3

You are awesome, thank you!
-- 
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