3 files changed, 36 insertions, 102 deletions

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index c71b6ed45e41..ee0e981aa9d1 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1480,8 +1480,6 @@ xfs_fs_fill_super(
         spin_lock_init(&mp->m_sb_lock);
         mutex_init(&mp->m_growlock);
         atomic_set(&mp->m_active_trans, 0);
-        INIT_LIST_HEAD(&mp->m_sync_list);
-        spin_lock_init(&mp->m_sync_lock);
 
         mp->m_super = sb;
         sb->s_fs_info = mp;
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 4a582d8100e4..af3275965c77 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -433,99 +433,6 @@ xfs_quiesce_attr(
         xfs_unmountfs_writesb(mp);
 }
 
-/*
- * Enqueue a work item to be picked up by the vfs xfssyncd thread.
- * Doing this has two advantages:
- * - It saves on stack space, which is tight in certain situations
- * - It can be used (with care) as a mechanism to avoid deadlocks.
- * Flushing while allocating in a full filesystem requires both.
- */
-STATIC void
-xfs_syncd_queue_work(
-        struct xfs_mount *mp,
-        void            *data,
-        void            (*syncer)(struct xfs_mount *, void *),
-        struct completion *completion)
-{
-        struct xfs_sync_work *work;
-
-        work = kmem_alloc(sizeof(struct xfs_sync_work), KM_SLEEP);
-        INIT_LIST_HEAD(&work->w_list);
-        work->w_syncer = syncer;
-        work->w_data = data;
-        work->w_mount = mp;
-        work->w_completion = completion;
-        spin_lock(&mp->m_sync_lock);
-        list_add_tail(&work->w_list, &mp->m_sync_list);
-        spin_unlock(&mp->m_sync_lock);
-        wake_up_process(mp->m_sync_task);
-}
-
-/*
- * Flush delayed allocate data, attempting to free up reserved space
- * from existing allocations.  At this point a new allocation attempt
- * has failed with ENOSPC and we are in the process of scratching our
- * heads, looking about for more room...
- */
-STATIC void
-xfs_flush_inodes_work(
-        struct xfs_mount *mp,
-        void            *arg)
-{
-        struct inode    *inode = arg;
-        xfs_sync_data(mp, SYNC_TRYLOCK);
-        xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT);
-        iput(inode);
-}
-
-void
-xfs_flush_inodes(
-        xfs_inode_t     *ip)
-{
-        struct inode    *inode = VFS_I(ip);
-        DECLARE_COMPLETION_ONSTACK(completion);
-
-        igrab(inode);
-        xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_inodes_work, &completion);
-        wait_for_completion(&completion);
-        xfs_log_force(ip->i_mount, XFS_LOG_SYNC);
-}
-
-STATIC int
-xfssyncd(
-        void                    *arg)
-{
-        struct xfs_mount        *mp = arg;
-        long                    timeleft;
-        xfs_sync_work_t         *work, *n;
-        LIST_HEAD               (tmp);
-
-        set_freezable();
-        timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
-        for (;;) {
-                if (list_empty(&mp->m_sync_list))
-                        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);
-                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->w_completion)
-                                complete(work->w_completion);
-                        kmem_free(work);
-                }
-        }
-
-        return 0;
-}
-
 static void
 xfs_syncd_queue_sync(
         struct xfs_mount        *mp)
@@ -562,16 +469,47 @@ xfs_sync_worker(
         xfs_syncd_queue_sync(mp);
 }
 
+/*
+ * Flush delayed allocate data, attempting to free up reserved space
+ * from existing allocations.  At this point a new allocation attempt
+ * has failed with ENOSPC and we are in the process of scratching our
+ * heads, looking about for more room.
+ *
+ * Queue a new data flush if there isn't one already in progress and
+ * wait for completion of the flush. This means that we only ever have one
+ * inode flush in progress no matter how many ENOSPC events are occurring and
+ * so will prevent the system from bogging down due to every concurrent
+ * ENOSPC event scanning all the active inodes in the system for writeback.
+ */
+void
+xfs_flush_inodes(
+        struct xfs_inode        *ip)
+{
+        struct xfs_mount        *mp = ip->i_mount;
+
+        queue_work(xfs_syncd_wq, &mp->m_flush_work);
+        flush_work_sync(&mp->m_flush_work);
+}
+
+STATIC void
+xfs_flush_worker(
+        struct work_struct *work)
+{
+        struct xfs_mount *mp = container_of(work,
+                                        struct xfs_mount, m_flush_work);
+
+        xfs_sync_data(mp, SYNC_TRYLOCK);
+        xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT);
+}
+
 int
 xfs_syncd_init(
         struct xfs_mount        *mp)
 {
+        INIT_WORK(&mp->m_flush_work, xfs_flush_worker);
         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);
         return 0;
 }
 
@@ -580,7 +518,7 @@ xfs_syncd_stop(
         struct xfs_mount        *mp)
 {
         cancel_delayed_work_sync(&mp->m_sync_work);
-        kthread_stop(mp->m_sync_task);
+        cancel_work_sync(&mp->m_flush_work);
 }
 
 void
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 2c11e62be888..a0ad90e95299 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -204,9 +204,7 @@ typedef struct xfs_mount {
 #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 */
-        struct list_head        m_sync_list;    /* sync thread work item list */
-        spinlock_t              m_sync_lock;    /* work item list lock */
+        struct work_struct      m_flush_work;   /* background inode flush */
         __int64_t               m_update_flags; /* sb flags we need to update
                                                    on the next remount,rw */
         struct shrinker         m_inode_shrink; /* inode reclaim shrinker */