linux-kernel - [PATCH 6.8 566/715] f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i

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Date: Sun, 24 Mar 2024 18:32:25 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Chao Yu <chao@...nel.org>,
	Jaegeuk Kim <jaegeuk@...nel.org>,
	Sasha Levin <sashal@...nel.org>
Subject: [PATCH 6.8 566/715] f2fs: compress: fix to cover f2fs_disable_compressed_file() w/ i_sem

From: Chao Yu <chao@...nel.org>

[ 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@...nel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 e4e249dd4c712..03c0d2e996fff 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4406,15 +4406,24 @@ 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;
 }
 
-- 
2.43.0