6 files changed, 194 insertions, 240 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 5ea402023ebd..9ef9ed2cfe2e 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -293,7 +293,6 @@ xfs_buf_allocate_memory(
         size_t                  nbytes, offset;
         gfp_t                   gfp_mask = xb_to_gfp(flags);
         unsigned short          page_count, i;
-        pgoff_t                 first;
         xfs_off_t               end;
         int                     error;
 
@@ -333,7 +332,6 @@ use_alloc_page:
                 return error;
 
         offset = bp->b_offset;
-        first = bp->b_file_offset >> PAGE_SHIFT;
         bp->b_flags |= _XBF_PAGES;
 
         for (i = 0; i < bp->b_page_count; i++) {
@@ -657,8 +655,6 @@ xfs_buf_readahead(
         xfs_off_t               ioff,
         size_t                  isize)
 {
-        struct backing_dev_info *bdi;
-
         if (bdi_read_congested(target->bt_bdi))
                 return;
 
@@ -919,8 +915,6 @@ xfs_buf_lock(
 
         if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
                 xfs_log_force(bp->b_target->bt_mount, 0);
-        if (atomic_read(&bp->b_io_remaining))
-                blk_flush_plug(current);
         down(&bp->b_sema);
         XB_SET_OWNER(bp);
 
@@ -1309,8 +1303,6 @@ xfs_buf_iowait(
 {
         trace_xfs_buf_iowait(bp, _RET_IP_);
 
-        if (atomic_read(&bp->b_io_remaining))
-                blk_flush_plug(current);
         wait_for_completion(&bp->b_iowait);
 
         trace_xfs_buf_iowait_done(bp, _RET_IP_);
@@ -1747,8 +1739,8 @@ xfsbufd(
         do {
                 long    age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
                 long    tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
-                int     count = 0;
                 struct list_head tmp;
+                struct blk_plug plug;
 
                 if (unlikely(freezing(current))) {
                         set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
@@ -1764,16 +1756,15 @@ xfsbufd(
 
                 xfs_buf_delwri_split(target, &tmp, age);
                 list_sort(NULL, &tmp, xfs_buf_cmp);
+
+                blk_start_plug(&plug);
                 while (!list_empty(&tmp)) {
                         struct xfs_buf *bp;
                         bp = list_first_entry(&tmp, struct xfs_buf, b_list);
                         list_del_init(&bp->b_list);
                         xfs_bdstrat_cb(bp);
-                        count++;
                 }
-                if (count)
-                        blk_flush_plug(current);
-
+                blk_finish_plug(&plug);
         } while (!kthread_should_stop());
 
         return 0;
@@ -1793,6 +1784,7 @@ xfs_flush_buftarg(
         int             pincount = 0;
         LIST_HEAD(tmp_list);
         LIST_HEAD(wait_list);
+        struct blk_plug plug;
 
         xfs_buf_runall_queues(xfsconvertd_workqueue);
         xfs_buf_runall_queues(xfsdatad_workqueue);
@@ -1807,6 +1799,8 @@ xfs_flush_buftarg(
          * we do that after issuing all the IO.
          */
         list_sort(NULL, &tmp_list, xfs_buf_cmp);
+
+        blk_start_plug(&plug);
         while (!list_empty(&tmp_list)) {
                 bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
                 ASSERT(target == bp->b_target);
@@ -1817,10 +1811,10 @@ xfs_flush_buftarg(
                 }
                 xfs_bdstrat_cb(bp);
         }
+        blk_finish_plug(&plug);
 
         if (wait) {
-                /* Expedite and wait for IO to complete. */
-                blk_flush_plug(current);
+                /* Wait for IO to complete. */
                 while (!list_empty(&wait_list)) {
                         bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
 
diff --git a/fs/xfs/linux-2.6/xfs_message.c b/fs/xfs/linux-2.6/xfs_message.c
index 508e06fd7d1e..3ca795609113 100644
--- a/fs/xfs/linux-2.6/xfs_message.c
+++ b/fs/xfs/linux-2.6/xfs_message.c
@@ -28,53 +28,47 @@
 /*
  * XFS logging functions
  */
-static int
+static void
 __xfs_printk(
         const char              *level,
         const struct xfs_mount  *mp,
         struct va_format        *vaf)
 {
         if (mp && mp->m_fsname)
-                return printk("%sXFS (%s): %pV\n", level, mp->m_fsname, vaf);
-        return printk("%sXFS: %pV\n", level, vaf);
+                printk("%sXFS (%s): %pV\n", level, mp->m_fsname, vaf);
+        printk("%sXFS: %pV\n", level, vaf);
 }
 
-int xfs_printk(
+void xfs_printk(
         const char              *level,
         const struct xfs_mount  *mp,
         const char              *fmt, ...)
 {
         struct va_format        vaf;
         va_list                 args;
-        int                      r;
 
         va_start(args, fmt);
 
         vaf.fmt = fmt;
         vaf.va = &args;
 
-        r = __xfs_printk(level, mp, &vaf);
+        __xfs_printk(level, mp, &vaf);
         va_end(args);
-
-        return r;
 }
 
 #define define_xfs_printk_level(func, kern_level)               \
-int func(const struct xfs_mount *mp, const char *fmt, ...)      \
+void func(const struct xfs_mount *mp, const char *fmt, ...)     \
 {                                                               \
         struct va_format        vaf;                            \
         va_list                 args;                           \
-        int                     r;                              \
                                                                 \
         va_start(args, fmt);                                    \
                                                                 \
         vaf.fmt = fmt;                                          \
         vaf.va = &args;                                         \
                                                                 \
-        r = __xfs_printk(kern_level, mp, &vaf);                 \
+        __xfs_printk(kern_level, mp, &vaf);                     \
         va_end(args);                                           \
-                                                                \
-        return r;                                               \
 }                                                               \
 
 define_xfs_printk_level(xfs_emerg, KERN_EMERG);
@@ -88,7 +82,7 @@ define_xfs_printk_level(xfs_info, KERN_INFO);
 define_xfs_printk_level(xfs_debug, KERN_DEBUG);
 #endif
 
-int
+void
 xfs_alert_tag(
         const struct xfs_mount  *mp,
         int                     panic_tag,
@@ -97,7 +91,6 @@ xfs_alert_tag(
         struct va_format        vaf;
         va_list                 args;
         int                     do_panic = 0;
-        int                     r;
 
         if (xfs_panic_mask && (xfs_panic_mask & panic_tag)) {
                 xfs_printk(KERN_ALERT, mp,
@@ -110,12 +103,10 @@ xfs_alert_tag(
         vaf.fmt = fmt;
         vaf.va = &args;
 
-        r = __xfs_printk(KERN_ALERT, mp, &vaf);
+        __xfs_printk(KERN_ALERT, mp, &vaf);
         va_end(args);
 
         BUG_ON(do_panic);
-
-        return r;
 }
 
 void
diff --git a/fs/xfs/linux-2.6/xfs_message.h b/fs/xfs/linux-2.6/xfs_message.h
index e77ffa16745b..f1b3fc1b6c4e 100644
--- a/fs/xfs/linux-2.6/xfs_message.h
+++ b/fs/xfs/linux-2.6/xfs_message.h
@@ -3,32 +3,34 @@
 
 struct xfs_mount;
 
-extern int xfs_printk(const char *level, const struct xfs_mount *mp,
+extern void xfs_printk(const char *level, const struct xfs_mount *mp,
                       const char *fmt, ...)
         __attribute__ ((format (printf, 3, 4)));
-extern int xfs_emerg(const struct xfs_mount *mp, const char *fmt, ...)
+extern void xfs_emerg(const struct xfs_mount *mp, const char *fmt, ...)
         __attribute__ ((format (printf, 2, 3)));
-extern int xfs_alert(const struct xfs_mount *mp, const char *fmt, ...)
+extern void xfs_alert(const struct xfs_mount *mp, const char *fmt, ...)
         __attribute__ ((format (printf, 2, 3)));
-extern int xfs_alert_tag(const struct xfs_mount *mp, int tag,
+extern void xfs_alert_tag(const struct xfs_mount *mp, int tag,
                          const char *fmt, ...)
         __attribute__ ((format (printf, 3, 4)));
-extern int xfs_crit(const struct xfs_mount *mp, const char *fmt, ...)
+extern void xfs_crit(const struct xfs_mount *mp, const char *fmt, ...)
         __attribute__ ((format (printf, 2, 3)));
-extern int xfs_err(const struct xfs_mount *mp, const char *fmt, ...)
+extern void xfs_err(const struct xfs_mount *mp, const char *fmt, ...)
         __attribute__ ((format (printf, 2, 3)));
-extern int xfs_warn(const struct xfs_mount *mp, const char *fmt, ...)
+extern void xfs_warn(const struct xfs_mount *mp, const char *fmt, ...)
         __attribute__ ((format (printf, 2, 3)));
-extern int xfs_notice(const struct xfs_mount *mp, const char *fmt, ...)
+extern void xfs_notice(const struct xfs_mount *mp, const char *fmt, ...)
         __attribute__ ((format (printf, 2, 3)));
-extern int xfs_info(const struct xfs_mount *mp, const char *fmt, ...)
+extern void xfs_info(const struct xfs_mount *mp, const char *fmt, ...)
         __attribute__ ((format (printf, 2, 3)));
 
 #ifdef DEBUG
-extern int xfs_debug(const struct xfs_mount *mp, const char *fmt, ...)
+extern void xfs_debug(const struct xfs_mount *mp, const char *fmt, ...)
         __attribute__ ((format (printf, 2, 3)));
 #else
-#define xfs_debug(mp, fmt, ...) (0)
+static inline void xfs_debug(const struct xfs_mount *mp, const char *fmt, ...)
+{
+}
 #endif
 
 extern void assfail(char *expr, char *f, int l);
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 1ba5c451da36..b38e58d02299 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -816,75 +816,6 @@ xfs_setup_devices(
         return 0;
 }
 
-/*
- * XFS AIL push thread support
- */
-void
-xfsaild_wakeup(
-        struct xfs_ail          *ailp,
-        xfs_lsn_t               threshold_lsn)
-{
-        /* only ever move the target forwards */
-        if (XFS_LSN_CMP(threshold_lsn, ailp->xa_target) > 0) {
-                ailp->xa_target = threshold_lsn;
-                wake_up_process(ailp->xa_task);
-        }
-}
-
-STATIC int
-xfsaild(
-        void    *data)
-{
-        struct xfs_ail  *ailp = data;
-        xfs_lsn_t       last_pushed_lsn = 0;
-        long            tout = 0; /* milliseconds */
-
-        while (!kthread_should_stop()) {
-                /*
-                 * for short sleeps indicating congestion, don't allow us to
-                 * get woken early. Otherwise all we do is bang on the AIL lock
-                 * without making progress.
-                 */
-                if (tout && tout <= 20)
-                        __set_current_state(TASK_KILLABLE);
-                else
-                        __set_current_state(TASK_INTERRUPTIBLE);
-                schedule_timeout(tout ?
-                                 msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
-
-                /* swsusp */
-                try_to_freeze();
-
-                ASSERT(ailp->xa_mount->m_log);
-                if (XFS_FORCED_SHUTDOWN(ailp->xa_mount))
-                        continue;
-
-                tout = xfsaild_push(ailp, &last_pushed_lsn);
-        }
-
-        return 0;
-}       /* xfsaild */
-
-int
-xfsaild_start(
-        struct xfs_ail  *ailp)
-{
-        ailp->xa_target = 0;
-        ailp->xa_task = kthread_run(xfsaild, ailp, "xfsaild/%s",
-                                    ailp->xa_mount->m_fsname);
-        if (IS_ERR(ailp->xa_task))
-                return -PTR_ERR(ailp->xa_task);
-        return 0;
-}
-
-void
-xfsaild_stop(
-        struct xfs_ail  *ailp)
-{
-        kthread_stop(ailp->xa_task);
-}
-
-
 /* Catch misguided souls that try to use this interface on XFS */
 STATIC struct inode *
 xfs_fs_alloc_inode(
@@ -1191,22 +1122,12 @@ 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;
@@ -1490,9 +1411,6 @@ 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);
-        init_waitqueue_head(&mp->m_wait_single_sync_task);
 
         mp->m_super = sb;
         sb->s_fs_info = mp;
@@ -1799,6 +1717,38 @@ xfs_destroy_zones(void)
 }
 
 STATIC int __init
+xfs_init_workqueues(void)
+{
+        /*
+         * 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)
+                goto out;
+
+        xfs_ail_wq = alloc_workqueue("xfsail", WQ_CPU_INTENSIVE, 8);
+        if (!xfs_ail_wq)
+                goto out_destroy_syncd;
+
+        return 0;
+
+out_destroy_syncd:
+        destroy_workqueue(xfs_syncd_wq);
+out:
+        return -ENOMEM;
+}
+
+STATIC void
+xfs_destroy_workqueues(void)
+{
+        destroy_workqueue(xfs_ail_wq);
+        destroy_workqueue(xfs_syncd_wq);
+}
+
+STATIC int __init
 init_xfs_fs(void)
 {
         int                     error;
@@ -1813,10 +1763,14 @@ init_xfs_fs(void)
         if (error)
                 goto out;
 
-        error = xfs_mru_cache_init();
+        error = xfs_init_workqueues();
         if (error)
                 goto out_destroy_zones;
 
+        error = xfs_mru_cache_init();
+        if (error)
+                goto out_destroy_wq;
+
         error = xfs_filestream_init();
         if (error)
                 goto out_mru_cache_uninit;
@@ -1833,6 +1787,10 @@ init_xfs_fs(void)
         if (error)
                 goto out_cleanup_procfs;
 
+        error = xfs_init_workqueues();
+        if (error)
+                goto out_sysctl_unregister;
+
         vfs_initquota();
 
         error = register_filesystem(&xfs_fs_type);
@@ -1850,6 +1808,8 @@ init_xfs_fs(void)
         xfs_filestream_uninit();
  out_mru_cache_uninit:
         xfs_mru_cache_uninit();
+ out_destroy_wq:
+        xfs_destroy_workqueues();
  out_destroy_zones:
         xfs_destroy_zones();
  out:
@@ -1866,6 +1826,7 @@ exit_xfs_fs(void)
         xfs_buf_terminate();
         xfs_filestream_uninit();
         xfs_mru_cache_uninit();
+        xfs_destroy_workqueues();
         xfs_destroy_zones();
 }
 
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 9cf35a688f53..e4f9c1b0836c 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -22,6 +22,7 @@
 #include "xfs_log.h"
 #include "xfs_inum.h"
 #include "xfs_trans.h"
+#include "xfs_trans_priv.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
 #include "xfs_mount.h"
@@ -39,6 +40,8 @@
 #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
@@ -431,62 +434,12 @@ 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)
+static void
+xfs_syncd_queue_sync(
+        struct xfs_mount        *mp)
 {
-        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);
+        queue_delayed_work(xfs_syncd_wq, &mp->m_sync_work,
+                                msecs_to_jiffies(xfs_syncd_centisecs * 10));
 }
 
 /*
@@ -496,9 +449,10 @@ xfs_flush_inodes(
  */
 STATIC void
 xfs_sync_worker(
-        struct xfs_mount *mp,
-        void            *unused)
+        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)) {
@@ -508,73 +462,106 @@ xfs_sync_worker(
                         error = xfs_fs_log_dummy(mp);
                 else
                         xfs_log_force(mp, 0);
-                xfs_reclaim_inodes(mp, 0);
                 error = xfs_qm_sync(mp, SYNC_TRYLOCK);
+
+                /* start pushing all the metadata that is currently dirty */
+                xfs_ail_push_all(mp->m_ail);
         }
-        mp->m_sync_seq++;
-        wake_up(&mp->m_wait_single_sync_task);
+
+        /* queue us up again */
+        xfs_syncd_queue_sync(mp);
 }
 
-STATIC int
-xfssyncd(
-        void                    *arg)
+/*
+ * Queue a new inode reclaim pass if there are reclaimable inodes and there
+ * isn't a reclaim pass already in progress. By default it runs every 5s based
+ * on the xfs syncd work default of 30s. Perhaps this should have it's own
+ * tunable, but that can be done if this method proves to be ineffective or too
+ * aggressive.
+ */
+static void
+xfs_syncd_queue_reclaim(
+        struct xfs_mount        *mp)
 {
-        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))
-                        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);
+        /*
+         * We can have inodes enter reclaim after we've shut down the syncd
+         * workqueue during unmount, so don't allow reclaim work to be queued
+         * during unmount.
+         */
+        if (!(mp->m_super->s_flags & MS_ACTIVE))
+                return;
 
-                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);
-                }
+        rcu_read_lock();
+        if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
+                queue_delayed_work(xfs_syncd_wq, &mp->m_reclaim_work,
+                        msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
         }
+        rcu_read_unlock();
+}
 
-        return 0;
+/*
+ * This is a fast pass over the inode cache to try to get reclaim moving on as
+ * many inodes as possible in a short period of time. It kicks itself every few
+ * seconds, as well as being kicked by the inode cache shrinker when memory
+ * goes low. It scans as quickly as possible avoiding locked inodes or those
+ * already being flushed, and once done schedules a future pass.
+ */
+STATIC void
+xfs_reclaim_worker(
+        struct work_struct *work)
+{
+        struct xfs_mount *mp = container_of(to_delayed_work(work),
+                                        struct xfs_mount, m_reclaim_work);
+
+        xfs_reclaim_inodes(mp, SYNC_TRYLOCK);
+        xfs_syncd_queue_reclaim(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)
 {
-        mp->m_sync_work.w_syncer = xfs_sync_worker;
-        mp->m_sync_work.w_mount = mp;
-        mp->m_sync_work.w_completion = NULL;
-        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);
+        INIT_WORK(&mp->m_flush_work, xfs_flush_worker);
+        INIT_DELAYED_WORK(&mp->m_sync_work, xfs_sync_worker);
+        INIT_DELAYED_WORK(&mp->m_reclaim_work, xfs_reclaim_worker);
+
+        xfs_syncd_queue_sync(mp);
+        xfs_syncd_queue_reclaim(mp);
+
         return 0;
 }
 
@@ -582,7 +569,9 @@ void
 xfs_syncd_stop(
         struct xfs_mount        *mp)
 {
-        kthread_stop(mp->m_sync_task);
+        cancel_delayed_work_sync(&mp->m_sync_work);
+        cancel_delayed_work_sync(&mp->m_reclaim_work);
+        cancel_work_sync(&mp->m_flush_work);
 }
 
 void
@@ -601,6 +590,10 @@ __xfs_inode_set_reclaim_tag(
                                 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
                                 XFS_ICI_RECLAIM_TAG);
                 spin_unlock(&ip->i_mount->m_perag_lock);
+
+                /* schedule periodic background inode reclaim */
+                xfs_syncd_queue_reclaim(ip->i_mount);
+
                 trace_xfs_perag_set_reclaim(ip->i_mount, pag->pag_agno,
                                                         -1, _RET_IP_);
         }
@@ -1017,7 +1010,13 @@ xfs_reclaim_inodes(
 }
 
 /*
- * Shrinker infrastructure.
+ * Inode cache shrinker.
+ *
+ * When called we make sure that there is a background (fast) inode reclaim in
+ * progress, while we will throttle the speed of reclaim via doiing synchronous
+ * reclaim of inodes. That means if we come across dirty inodes, we wait for
+ * them to be cleaned, which we hope will not be very long due to the
+ * background walker having already kicked the IO off on those dirty inodes.
  */
 static int
 xfs_reclaim_inode_shrink(
@@ -1032,10 +1031,15 @@ xfs_reclaim_inode_shrink(
 
         mp = container_of(shrink, struct xfs_mount, m_inode_shrink);
         if (nr_to_scan) {
+                /* kick background reclaimer and push the AIL */
+                xfs_syncd_queue_reclaim(mp);
+                xfs_ail_push_all(mp->m_ail);
+
                 if (!(gfp_mask & __GFP_FS))
                         return -1;
 
-                xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK, &nr_to_scan);
+                xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT,
+                                        &nr_to_scan);
                 /* terminate if we don't exhaust the scan */
                 if (nr_to_scan > 0)
                         return -1;
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);