ext4: fix deadlock when converting an inline directory in nojournal mode

tytso · gregkh · commit 0b1c4357bb21 · 2023-05-17T13:59:11.000+02:00
commit f4ce24f upstream. In no journal mode, ext4_finish_convert_inline_dir() can self-deadlock by calling ext4_handle_dirty_dirblock() when it already has taken the directory lock. There is a similar self-deadlock in ext4_incvert_inline_data_nolock() for data files which we'll fix at the same time. A simple reproducer demonstrating the problem: mke2fs -Fq -t ext2 -O inline_data -b 4k /dev/vdc 64 mount -t ext4 -o dirsync /dev/vdc /vdc cd /vdc mkdir file0 cd file0 touch file0 touch file1 attr -s BurnSpaceInEA -V abcde . touch supercalifragilisticexpialidocious Cc: stable@kernel.org Link: https://lore.kernel.org/r/20230507021608.1290720-1-tytso@mit.edu Reported-by: syzbot+91dccab7c64e2850a4e5@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=ba84cc80a9491d65416bc7877e1650c87530fe8a Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
@@ -1177,6 +1177,7 @@ static int ext4_finish_convert_inline_dir(handle_t *handle,
 		ext4_initialize_dirent_tail(dir_block,
 					    inode->i_sb->s_blocksize);
 	set_buffer_uptodate(dir_block);
+	unlock_buffer(dir_block);
 	err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
 	if (err)
 		return err;
@@ -1251,14 +1252,14 @@ static int ext4_convert_inline_data_nolock(handle_t *handle,
 	if (!S_ISDIR(inode->i_mode)) {
 		memcpy(data_bh->b_data, buf, inline_size);
 		set_buffer_uptodate(data_bh);
+		unlock_buffer(data_bh);
 		error = ext4_handle_dirty_metadata(handle,
 						   inode, data_bh);
 	} else {
 		error = ext4_finish_convert_inline_dir(handle, inode, data_bh,
 						       buf, inline_size);
 	}
 
-	unlock_buffer(data_bh);
 out_restore:
 	if (error)
 		ext4_restore_inline_data(handle, inode, iloc, buf, inline_size);
