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xfs: drop iolock from reclaim context to appease lockdep

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Lockdep complains about use of the iolock in inode reclaim context
because it doesn't understand that reclaim has the last reference to
the inode, and thus an iolock->reclaim->iolock deadlock is not
possible.

The iolock is technically not necessary in xfs_inactive() and was
only added to appease an assert in xfs_free_eofblocks(), which can
be called from other non-reclaim contexts. Therefore, just kill the
assert and drop the use of the iolock from reclaim context to quiet
lockdep.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Brian Foster 2017-04-11 10:50:05 -07:00 committed by Darrick J. Wong
parent 5146d0b762
commit 3b4683c294
2 changed files with 8 additions and 9 deletions
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8
fs/xfs/xfs_bmap_util.c
View file

@ -903,9 +903,9 @@ xfs_can_free_eofblocks(struct xfs_inode *ip, bool force)
}
/*
* This is called by xfs_inactive to free any blocks beyond eof
* when the link count isn't zero and by xfs_dm_punch_hole() when
* punching a hole to EOF.
* This is called to free any blocks beyond eof. The caller must hold
* IOLOCK_EXCL unless we are in the inode reclaim path and have the only
* reference to the inode.
*/
int
xfs_free_eofblocks(
@ -920,8 +920,6 @@ xfs_free_eofblocks(
struct xfs_bmbt_irec imap;
struct xfs_mount *mp = ip->i_mount;
ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
/*
* Figure out if there are any blocks beyond the end
* of the file. If not, then there is nothing to do.

9
fs/xfs/xfs_inode.c
View file

@ -1906,12 +1906,13 @@ xfs_inactive(
* force is true because we are evicting an inode from the
* cache. Post-eof blocks must be freed, lest we end up with
* broken free space accounting.
*
* Note: don't bother with iolock here since lockdep complains
* about acquiring it in reclaim context. We have the only
* reference to the inode at this point anyways.
*/
if (xfs_can_free_eofblocks(ip, true)) {
xfs_ilock(ip, XFS_IOLOCK_EXCL);
if (xfs_can_free_eofblocks(ip, true))
xfs_free_eofblocks(ip);
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
}
return;
}