ext4: add lockdep annotations for i_data_sem
authorTheodore Ts'o <tytso@mit.edu>
Fri, 1 Apr 2016 05:31:28 +0000 (01:31 -0400)
committerTheodore Ts'o <tytso@mit.edu>
Fri, 1 Apr 2016 05:31:28 +0000 (01:31 -0400)
commitdaf647d2dd58cec59570d7698a45b98e580f2076
tree91d950bb640b3e16c36bf09265d46bd07dd0fba0
parent1028b55bafb7611dda1d8fed2aeca16a436b7dff
ext4: add lockdep annotations for i_data_sem

With the internal Quota feature, mke2fs creates empty quota inodes and
quota usage tracking is enabled as soon as the file system is mounted.
Since quotacheck is no longer preallocating all of the blocks in the
quota inode that are likely needed to be written to, we are now seeing
a lockdep false positive caused by needing to allocate a quota block
from inside ext4_map_blocks(), while holding i_data_sem for a data
inode.  This results in this complaint:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&ei->i_data_sem);
                                lock(&s->s_dquot.dqio_mutex);
                                lock(&ei->i_data_sem);
   lock(&s->s_dquot.dqio_mutex);

Google-Bug-Id: 27907753

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
fs/ext4/ext4.h
fs/ext4/move_extent.c
fs/ext4/super.c