4 files changed, 63 insertions, 61 deletions

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 1ba5c451da36..c71b6ed45e41 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1191,22 +1191,12 @@ xfs_fs_sync_fs(
                 return -error;
 
         if (laptop_mode) {
-                int     prev_sync_seq = mp->m_sync_seq;
-
                 /*
                  * The disk must be active because we're syncing.
                  * We schedule xfssyncd now (now that the disk is
                  * active) instead of later (when it might not be).
                  */
-                wake_up_process(mp->m_sync_task);
-                /*
-                 * We have to wait for the sync iteration to complete.
-                 * If we don't, the disk activity caused by the sync
-                 * will come after the sync is completed, and that
-                 * triggers another sync from laptop mode.
-                 */
-                wait_event(mp->m_wait_single_sync_task,
-                                mp->m_sync_seq != prev_sync_seq);
+                flush_delayed_work_sync(&mp->m_sync_work);
         }
 
         return 0;
@@ -1492,7 +1482,6 @@ xfs_fs_fill_super(
         atomic_set(&mp->m_active_trans, 0);
         INIT_LIST_HEAD(&mp->m_sync_list);
         spin_lock_init(&mp->m_sync_lock);
-        init_waitqueue_head(&mp->m_wait_single_sync_task);
 
         mp->m_super = sb;
         sb->s_fs_info = mp;
@@ -1833,13 +1822,27 @@ init_xfs_fs(void)
         if (error)
                 goto out_cleanup_procfs;
 
+        /*
+         * max_active is set to 8 to give enough concurency to allow
+         * multiple work operations on each CPU to run. This allows multiple
+         * filesystems to be running sync work concurrently, and scales with
+         * the number of CPUs in the system.
+         */
+        xfs_syncd_wq = alloc_workqueue("xfssyncd", WQ_CPU_INTENSIVE, 8);
+        if (!xfs_syncd_wq) {
+                error = -ENOMEM;
+                goto out_sysctl_unregister;
+        }
+
         vfs_initquota();
 
         error = register_filesystem(&xfs_fs_type);
         if (error)
-                goto out_sysctl_unregister;
+                goto out_destroy_xfs_syncd;
         return 0;
 
+ out_destroy_xfs_syncd:
+        destroy_workqueue(xfs_syncd_wq);
  out_sysctl_unregister:
         xfs_sysctl_unregister();
  out_cleanup_procfs:
@@ -1861,6 +1864,7 @@ exit_xfs_fs(void)
 {
         vfs_exitquota();
         unregister_filesystem(&xfs_fs_type);
+        destroy_workqueue(xfs_syncd_wq);
         xfs_sysctl_unregister();
         xfs_cleanup_procfs();
         xfs_buf_terminate();
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 594cd822d84d..4a582d8100e4 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -39,6 +39,8 @@
 #include <linux/kthread.h>
 #include <linux/freezer.h>
 
+struct workqueue_struct *xfs_syncd_wq;  /* sync workqueue */
+
 /*
  * The inode lookup is done in batches to keep the amount of lock traffic and
  * radix tree lookups to a minimum. The batch size is a trade off between
@@ -489,32 +491,6 @@ xfs_flush_inodes(
         xfs_log_force(ip->i_mount, XFS_LOG_SYNC);
 }
 
-/*
- * Every sync period we need to unpin all items, reclaim inodes and sync
- * disk quotas.  We might need to cover the log to indicate that the
- * filesystem is idle and not frozen.
- */
-STATIC void
-xfs_sync_worker(
-        struct xfs_mount *mp,
-        void            *unused)
-{
-        int             error;
-
-        if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
-                /* dgc: errors ignored here */
-                if (mp->m_super->s_frozen == SB_UNFROZEN &&
-                    xfs_log_need_covered(mp))
-                        error = xfs_fs_log_dummy(mp);
-                else
-                        xfs_log_force(mp, 0);
-                xfs_reclaim_inodes(mp, 0);
-                error = xfs_qm_sync(mp, SYNC_TRYLOCK);
-        }
-        mp->m_sync_seq++;
-        wake_up(&mp->m_wait_single_sync_task);
-}
-
 STATIC int
 xfssyncd(
         void                    *arg)
@@ -528,34 +504,19 @@ xfssyncd(
         timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
         for (;;) {
                 if (list_empty(&mp->m_sync_list))
-                        timeleft = schedule_timeout_interruptible(timeleft);
+                        schedule_timeout_interruptible(timeleft);
                 /* swsusp */
                 try_to_freeze();
                 if (kthread_should_stop() && list_empty(&mp->m_sync_list))
                         break;
 
                 spin_lock(&mp->m_sync_lock);
-                /*
-                 * We can get woken by laptop mode, to do a sync -
-                 * that's the (only!) case where the list would be
-                 * empty with time remaining.
-                 */
-                if (!timeleft || list_empty(&mp->m_sync_list)) {
-                        if (!timeleft)
-                                timeleft = xfs_syncd_centisecs *
-                                                        msecs_to_jiffies(10);
-                        INIT_LIST_HEAD(&mp->m_sync_work.w_list);
-                        list_add_tail(&mp->m_sync_work.w_list,
-                                        &mp->m_sync_list);
-                }
                 list_splice_init(&mp->m_sync_list, &tmp);
                 spin_unlock(&mp->m_sync_lock);
 
                 list_for_each_entry_safe(work, n, &tmp, w_list) {
                         (*work->w_syncer)(mp, work->w_data);
                         list_del(&work->w_list);
-                        if (work == &mp->m_sync_work)
-                                continue;
                         if (work->w_completion)
                                 complete(work->w_completion);
                         kmem_free(work);
@@ -565,13 +526,49 @@ xfssyncd(
         return 0;
 }
 
+static void
+xfs_syncd_queue_sync(
+        struct xfs_mount        *mp)
+{
+        queue_delayed_work(xfs_syncd_wq, &mp->m_sync_work,
+                                msecs_to_jiffies(xfs_syncd_centisecs * 10));
+}
+
+/*
+ * Every sync period we need to unpin all items, reclaim inodes and sync
+ * disk quotas.  We might need to cover the log to indicate that the
+ * filesystem is idle and not frozen.
+ */
+STATIC void
+xfs_sync_worker(
+        struct work_struct *work)
+{
+        struct xfs_mount *mp = container_of(to_delayed_work(work),
+                                        struct xfs_mount, m_sync_work);
+        int             error;
+
+        if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
+                /* dgc: errors ignored here */
+                if (mp->m_super->s_frozen == SB_UNFROZEN &&
+                    xfs_log_need_covered(mp))
+                        error = xfs_fs_log_dummy(mp);
+                else
+                        xfs_log_force(mp, 0);
+                xfs_reclaim_inodes(mp, 0);
+                error = xfs_qm_sync(mp, SYNC_TRYLOCK);
+        }
+
+        /* queue us up again */
+        xfs_syncd_queue_sync(mp);
+}
+
 int
 xfs_syncd_init(
         struct xfs_mount        *mp)
 {
-        mp->m_sync_work.w_syncer = xfs_sync_worker;
-        mp->m_sync_work.w_mount = mp;
-        mp->m_sync_work.w_completion = NULL;
+        INIT_DELAYED_WORK(&mp->m_sync_work, xfs_sync_worker);
+        xfs_syncd_queue_sync(mp);
+
         mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd/%s", mp->m_fsname);
         if (IS_ERR(mp->m_sync_task))
                 return -PTR_ERR(mp->m_sync_task);
@@ -582,6 +579,7 @@ void
 xfs_syncd_stop(
         struct xfs_mount        *mp)
 {
+        cancel_delayed_work_sync(&mp->m_sync_work);
         kthread_stop(mp->m_sync_task);
 }
 
diff --git a/fs/xfs/linux-2.6/xfs_sync.h b/fs/xfs/linux-2.6/xfs_sync.h
index 32ba6628290c..e3a6ad27415f 100644
--- a/fs/xfs/linux-2.6/xfs_sync.h
+++ b/fs/xfs/linux-2.6/xfs_sync.h
@@ -32,6 +32,8 @@ typedef struct xfs_sync_work {
 #define SYNC_WAIT               0x0001  /* wait for i/o to complete */
 #define SYNC_TRYLOCK            0x0002  /* only try to lock inodes */
 
+extern struct workqueue_struct  *xfs_syncd_wq;  /* sync workqueue */
+
 int xfs_syncd_init(struct xfs_mount *mp);
 void xfs_syncd_stop(struct xfs_mount *mp);
 
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index a62e8971539d..2c11e62be888 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -203,12 +203,10 @@ typedef struct xfs_mount {
         struct mutex            m_icsb_mutex;   /* balancer sync lock */
 #endif
         struct xfs_mru_cache    *m_filestream;  /* per-mount filestream data */
+        struct delayed_work     m_sync_work;    /* background sync work */
         struct task_struct      *m_sync_task;   /* generalised sync thread */
-        xfs_sync_work_t         m_sync_work;    /* work item for VFS_SYNC */
         struct list_head        m_sync_list;    /* sync thread work item list */
         spinlock_t              m_sync_lock;    /* work item list lock */
-        int                     m_sync_seq;     /* sync thread generation no. */
-        wait_queue_head_t       m_wait_single_sync_task;
         __int64_t               m_update_flags; /* sb flags we need to update
                                                    on the next remount,rw */
         struct shrinker         m_inode_shrink; /* inode reclaim shrinker */