Commit 4b674b9a authored by Brian Foster's avatar Brian Foster Committed by Darrick J. Wong

xfs: acquire superblock freeze protection on eofblocks scans

The filesystem freeze sequence in XFS waits on any background
eofblocks or cowblocks scans to complete before the filesystem is
quiesced. At this point, the freezer has already stopped the
transaction subsystem, however, which means a truncate or cowblock
cancellation in progress is likely blocked in transaction
allocation. This results in a deadlock between freeze and the
associated scanner.

Fix this problem by holding superblock write protection across calls
into the block reapers. Since protection for background scans is
acquired from the workqueue task context, trylock to avoid a similar
deadlock between freeze and blocking on the write lock.

Fixes: d6b636eb ("xfs: halt auto-reclamation activities while rebuilding rmap")
Reported-by: default avatarPaul Furtado <paulfurtado91@gmail.com>
Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarChandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarAllison Collins <allison.henderson@oracle.com>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent 8f3d9f35
......@@ -911,7 +911,12 @@ xfs_eofblocks_worker(
{
struct xfs_mount *mp = container_of(to_delayed_work(work),
struct xfs_mount, m_eofblocks_work);
if (!sb_start_write_trylock(mp->m_super))
return;
xfs_icache_free_eofblocks(mp, NULL);
sb_end_write(mp->m_super);
xfs_queue_eofblocks(mp);
}
......@@ -938,7 +943,12 @@ xfs_cowblocks_worker(
{
struct xfs_mount *mp = container_of(to_delayed_work(work),
struct xfs_mount, m_cowblocks_work);
if (!sb_start_write_trylock(mp->m_super))
return;
xfs_icache_free_cowblocks(mp, NULL);
sb_end_write(mp->m_super);
xfs_queue_cowblocks(mp);
}
......
......@@ -2363,7 +2363,10 @@ xfs_file_ioctl(
if (error)
return error;
return xfs_icache_free_eofblocks(mp, &keofb);
sb_start_write(mp->m_super);
error = xfs_icache_free_eofblocks(mp, &keofb);
sb_end_write(mp->m_super);
return error;
}
default:
......
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