Patch "f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i_sem" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i_sem

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     f2fs-compress-fix-to-cover-f2fs_disable_compressed_f.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 1804532ff3e71b05023ef0cc46055d7dfb08e93d
Author: Chao Yu <chao@xxxxxxxxxx>
Date:   Mon Jan 22 10:23:13 2024 +0800

    f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i_sem
    
    [ Upstream commit 2f9420d3a94aeebd92db88f00f4f2f1a3bd3f6cf ]
    
    - 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@xxxxxxxxxx>
    Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2e2792a49de0f..95fa1f7a89707 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4396,15 +4396,24 @@ 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;
 }