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@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2afb91471b5357ccf9b57fac979b7434fafc2ae6..a81091a5e282d09d3105c5d01e0120a90c9642b3 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4367,15 +4367,24 @@ 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;
 }