ext4: fix lockdep warning when enabling MMP

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commit 949f95ff39 upstream.

When we enable MMP in ext4_multi_mount_protect() during mount or
remount, we end up calling sb_start_write() from write_mmp_block(). This
triggers lockdep warning because freeze protection ranks above s_umount
semaphore we are holding during mount / remount. The problem is harmless
because we are guaranteed the filesystem is not frozen during mount /
remount but still let's fix the warning by not grabbing freeze
protection from ext4_multi_mount_protect().

Cc: stable@kernel.org
Reported-by: syzbot+6b7df7d5506b32467149@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=ab7e5b6f400b7778d46f01841422e5718fb81843
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230411121019.21940-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Jan Kara 2023-04-11 14:10:19 +02:00 • committed by Greg Kroah-Hartman

parent 6e7a97628f

commit 19fb73b8ea

1 changed files with 21 additions and 9 deletions

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fs/ext4/mmp.c

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