1 files changed, 60 insertions, 27 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index b306265caa33..4556a4c31e36 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -33,6 +33,7 @@
 #include <linux/migrate.h>
 #include <linux/backing-dev.h>
 #include <linux/freezer.h>
+#include <linux/list_sort.h>
 
 #include "xfs_sb.h"
 #include "xfs_inum.h"
@@ -1877,14 +1878,42 @@ xfs_buf_delwri_split(
 
 }
 
+/*
+ * Compare function is more complex than it needs to be because
+ * the return value is only 32 bits and we are doing comparisons
+ * on 64 bit values
+ */
+static int
+xfs_buf_cmp(
+        void            *priv,
+        struct list_head *a,
+        struct list_head *b)
+{
+        struct xfs_buf  *ap = container_of(a, struct xfs_buf, b_list);
+        struct xfs_buf  *bp = container_of(b, struct xfs_buf, b_list);
+        xfs_daddr_t             diff;
+
+        diff = ap->b_bn - bp->b_bn;
+        if (diff < 0)
+                return -1;
+        if (diff > 0)
+                return 1;
+        return 0;
+}
+
+void
+xfs_buf_delwri_sort(
+        xfs_buftarg_t   *target,
+        struct list_head *list)
+{
+        list_sort(NULL, list, xfs_buf_cmp);
+}
+
 STATIC int
 xfsbufd(
         void            *data)
 {
-        struct list_head tmp;
-        xfs_buftarg_t   *target = (xfs_buftarg_t *)data;
-        int             count;
-        xfs_buf_t       *bp;
+        xfs_buftarg_t   *target = (xfs_buftarg_t *)data;
 
         current->flags |= PF_MEMALLOC;
 
@@ -1893,6 +1922,8 @@ 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;
 
                 if (unlikely(freezing(current))) {
                         set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
@@ -1907,11 +1938,10 @@ xfsbufd(
                 schedule_timeout_interruptible(tout);
 
                 xfs_buf_delwri_split(target, &tmp, age);
-                count = 0;
+                list_sort(NULL, &tmp, xfs_buf_cmp);
                 while (!list_empty(&tmp)) {
-                        bp = list_entry(tmp.next, xfs_buf_t, b_list);
-                        ASSERT(target == bp->b_target);
-
+                        struct xfs_buf *bp;
+                        bp = list_first_entry(&tmp, struct xfs_buf, b_list);
                         list_del_init(&bp->b_list);
                         xfs_buf_iostrategy(bp);
                         count++;
@@ -1937,42 +1967,45 @@ xfs_flush_buftarg(
         xfs_buftarg_t   *target,
         int             wait)
 {
-        struct list_head tmp;
-        xfs_buf_t       *bp, *n;
+        xfs_buf_t       *bp;
         int             pincount = 0;
+        LIST_HEAD(tmp_list);
+        LIST_HEAD(wait_list);
 
         xfs_buf_runall_queues(xfsconvertd_workqueue);
         xfs_buf_runall_queues(xfsdatad_workqueue);
         xfs_buf_runall_queues(xfslogd_workqueue);
 
         set_bit(XBT_FORCE_FLUSH, &target->bt_flags);
-        pincount = xfs_buf_delwri_split(target, &tmp, 0);
+        pincount = xfs_buf_delwri_split(target, &tmp_list, 0);
 
         /*
-         * Dropped the delayed write list lock, now walk the temporary list
+         * Dropped the delayed write list lock, now walk the temporary list.
+         * All I/O is issued async and then if we need to wait for completion
+         * we do that after issuing all the IO.
          */
-        list_for_each_entry_safe(bp, n, &tmp, b_list) {
+        list_sort(NULL, &tmp_list, xfs_buf_cmp);
+        while (!list_empty(&tmp_list)) {
+                bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
                 ASSERT(target == bp->b_target);
-                if (wait)
+                list_del_init(&bp->b_list);
+                if (wait) {
                         bp->b_flags &= ~XBF_ASYNC;
-                else
-                        list_del_init(&bp->b_list);
-
+                        list_add(&bp->b_list, &wait_list);
+                }
                 xfs_buf_iostrategy(bp);
         }
 
-        if (wait)
+        if (wait) {
+                /* Expedite and wait for IO to complete. */
                 blk_run_address_space(target->bt_mapping);
+                while (!list_empty(&wait_list)) {
+                        bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
 
-        /*
-         * Remaining list items must be flushed before returning
-         */
-        while (!list_empty(&tmp)) {
-                bp = list_entry(tmp.next, xfs_buf_t, b_list);
-
-                list_del_init(&bp->b_list);
-                xfs_iowait(bp);
-                xfs_buf_relse(bp);
+                        list_del_init(&bp->b_list);
+                        xfs_iowait(bp);
+                        xfs_buf_relse(bp);
+                }
         }
 
         return pincount;