xfs: add background scanning to clear eofblocks inodes

Create a new mount workqueue and delayed_work to enable background
scanning and freeing of eofblocks inodes. The scanner kicks in once
speculative preallocation occurs and stops requeueing itself when
no eofblocks inodes exist.

The scan interval is based on the new
'speculative_prealloc_lifetime' tunable (default to 5m). The
background scanner performs unfiltered, best effort scans (which
skips inodes under lock contention or with a dirty cache mapping).

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 3d9ea947e9f8..ab8839b26272 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -874,8 +874,15 @@ xfs_init_mount_workqueues(
         if (!mp->m_log_workqueue)
                 goto out_destroy_reclaim;
 
+        mp->m_eofblocks_workqueue = alloc_workqueue("xfs-eofblocks/%s",
+                        WQ_NON_REENTRANT, 0, mp->m_fsname);
+        if (!mp->m_eofblocks_workqueue)
+                goto out_destroy_log;
+
         return 0;
 
+out_destroy_log:
+        destroy_workqueue(mp->m_log_workqueue);
 out_destroy_reclaim:
         destroy_workqueue(mp->m_reclaim_workqueue);
 out_destroy_cil:
@@ -892,6 +899,7 @@ STATIC void
 xfs_destroy_mount_workqueues(
         struct xfs_mount        *mp)
 {
+        destroy_workqueue(mp->m_eofblocks_workqueue);
         destroy_workqueue(mp->m_log_workqueue);
         destroy_workqueue(mp->m_reclaim_workqueue);
         destroy_workqueue(mp->m_cil_workqueue);
@@ -1393,6 +1401,7 @@ xfs_fs_fill_super(
         mutex_init(&mp->m_growlock);
         atomic_set(&mp->m_active_trans, 0);
         INIT_DELAYED_WORK(&mp->m_reclaim_work, xfs_reclaim_worker);
+        INIT_DELAYED_WORK(&mp->m_eofblocks_work, xfs_eofblocks_worker);
 
         mp->m_super = sb;
         sb->s_fs_info = mp;