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Commit b4fa4768 authored by Theodore Ts'o's avatar Theodore Ts'o Committed by Greg Kroah-Hartman
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ext4: fix deadlock when converting an inline directory in nojournal mode 

commit f4ce24f54d9cca4f09a395f3eecce20d6bec4663 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: default avatar <syzbot+91dccab7c64e2850a4e5@syzkaller.appspotmail.com>
Link: https://syzkaller.appspot.com/bug?id=ba84cc80a9491d65416bc7877e1650c87530fe8a


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2dda2029

fs/ext4/inline.c

+2 −1
Original line number Diff line number Diff line
@@ -1172,6 +1172,7 @@ 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;
@@ -1245,6 +1246,7 @@ 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 {
@@ -1252,7 +1254,6 @@ static int ext4_convert_inline_data_nolock(handle_t *handle, 
						       buf, inline_size);

	}



	unlock_buffer(data_bh);

out_restore:

	if (error)

		ext4_restore_inline_data(handle, inode, iloc, buf, inline_size);