Merge branch 'for-linus' of git://neil.brown.name/md
[pandora-kernel.git] / fs / xfs / xfs_log.c
index a14cd89..34817ad 100644 (file)
@@ -150,6 +150,117 @@ xlog_grant_add_space(
        } while (head_val != old);
 }
 
+STATIC bool
+xlog_reserveq_wake(
+       struct log              *log,
+       int                     *free_bytes)
+{
+       struct xlog_ticket      *tic;
+       int                     need_bytes;
+
+       list_for_each_entry(tic, &log->l_reserveq, t_queue) {
+               if (tic->t_flags & XLOG_TIC_PERM_RESERV)
+                       need_bytes = tic->t_unit_res * tic->t_cnt;
+               else
+                       need_bytes = tic->t_unit_res;
+
+               if (*free_bytes < need_bytes)
+                       return false;
+               *free_bytes -= need_bytes;
+
+               trace_xfs_log_grant_wake_up(log, tic);
+               wake_up(&tic->t_wait);
+       }
+
+       return true;
+}
+
+STATIC bool
+xlog_writeq_wake(
+       struct log              *log,
+       int                     *free_bytes)
+{
+       struct xlog_ticket      *tic;
+       int                     need_bytes;
+
+       list_for_each_entry(tic, &log->l_writeq, t_queue) {
+               ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
+
+               need_bytes = tic->t_unit_res;
+
+               if (*free_bytes < need_bytes)
+                       return false;
+               *free_bytes -= need_bytes;
+
+               trace_xfs_log_regrant_write_wake_up(log, tic);
+               wake_up(&tic->t_wait);
+       }
+
+       return true;
+}
+
+STATIC int
+xlog_reserveq_wait(
+       struct log              *log,
+       struct xlog_ticket      *tic,
+       int                     need_bytes)
+{
+       list_add_tail(&tic->t_queue, &log->l_reserveq);
+
+       do {
+               if (XLOG_FORCED_SHUTDOWN(log))
+                       goto shutdown;
+               xlog_grant_push_ail(log, need_bytes);
+
+               XFS_STATS_INC(xs_sleep_logspace);
+               trace_xfs_log_grant_sleep(log, tic);
+
+               xlog_wait(&tic->t_wait, &log->l_grant_reserve_lock);
+               trace_xfs_log_grant_wake(log, tic);
+
+               spin_lock(&log->l_grant_reserve_lock);
+               if (XLOG_FORCED_SHUTDOWN(log))
+                       goto shutdown;
+       } while (xlog_space_left(log, &log->l_grant_reserve_head) < need_bytes);
+
+       list_del_init(&tic->t_queue);
+       return 0;
+shutdown:
+       list_del_init(&tic->t_queue);
+       return XFS_ERROR(EIO);
+}
+
+STATIC int
+xlog_writeq_wait(
+       struct log              *log,
+       struct xlog_ticket      *tic,
+       int                     need_bytes)
+{
+       list_add_tail(&tic->t_queue, &log->l_writeq);
+
+       do {
+               if (XLOG_FORCED_SHUTDOWN(log))
+                       goto shutdown;
+               xlog_grant_push_ail(log, need_bytes);
+
+               XFS_STATS_INC(xs_sleep_logspace);
+               trace_xfs_log_regrant_write_sleep(log, tic);
+
+               xlog_wait(&tic->t_wait, &log->l_grant_write_lock);
+               trace_xfs_log_regrant_write_wake(log, tic);
+
+               spin_lock(&log->l_grant_write_lock);
+               if (XLOG_FORCED_SHUTDOWN(log))
+                       goto shutdown;
+       } while (xlog_space_left(log, &log->l_grant_write_head) < need_bytes);
+
+       list_del_init(&tic->t_queue);
+       return 0;
+shutdown:
+       list_del_init(&tic->t_queue);
+       return XFS_ERROR(EIO);
+}
+
 static void
 xlog_tic_reset_res(xlog_ticket_t *tic)
 {
@@ -350,8 +461,19 @@ xfs_log_reserve(
                retval = xlog_grant_log_space(log, internal_ticket);
        }
 
+       if (unlikely(retval)) {
+               /*
+                * If we are failing, make sure the ticket doesn't have any
+                * current reservations.  We don't want to add this back
+                * when the ticket/ transaction gets cancelled.
+                */
+               internal_ticket->t_curr_res = 0;
+               /* ungrant will give back unit_res * t_cnt. */
+               internal_ticket->t_cnt = 0;
+       }
+
        return retval;
-}      /* xfs_log_reserve */
+}
 
 
 /*
@@ -2481,8 +2603,8 @@ restart:
 /*
  * Atomically get the log space required for a log ticket.
  *
- * Once a ticket gets put onto the reserveq, it will only return after
- * the needed reservation is satisfied.
+ * Once a ticket gets put onto the reserveq, it will only return after the
+ * needed reservation is satisfied.
  *
  * This function is structured so that it has a lock free fast path. This is
  * necessary because every new transaction reservation will come through this
@@ -2490,113 +2612,53 @@ restart:
  * every pass.
  *
  * As tickets are only ever moved on and off the reserveq under the
- * l_grant_reserve_lock, we only need to take that lock if we are going
- * to add the ticket to the queue and sleep. We can avoid taking the lock if the
- * ticket was never added to the reserveq because the t_queue list head will be
- * empty and we hold the only reference to it so it can safely be checked
- * unlocked.
+ * l_grant_reserve_lock, we only need to take that lock if we are going to add
+ * the ticket to the queue and sleep. We can avoid taking the lock if the ticket
+ * was never added to the reserveq because the t_queue list head will be empty
+ * and we hold the only reference to it so it can safely be checked unlocked.
  */
 STATIC int
-xlog_grant_log_space(xlog_t       *log,
-                    xlog_ticket_t *tic)
+xlog_grant_log_space(
+       struct log              *log,
+       struct xlog_ticket      *tic)
 {
-       int              free_bytes;
-       int              need_bytes;
+       int                     free_bytes, need_bytes;
+       int                     error = 0;
 
-#ifdef DEBUG
-       if (log->l_flags & XLOG_ACTIVE_RECOVERY)
-               panic("grant Recovery problem");
-#endif
+       ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
 
        trace_xfs_log_grant_enter(log, tic);
 
+       /*
+        * If there are other waiters on the queue then give them a chance at
+        * logspace before us.  Wake up the first waiters, if we do not wake
+        * up all the waiters then go to sleep waiting for more free space,
+        * otherwise try to get some space for this transaction.
+        */
        need_bytes = tic->t_unit_res;
        if (tic->t_flags & XFS_LOG_PERM_RESERV)
                need_bytes *= tic->t_ocnt;
-
-       /* something is already sleeping; insert new transaction at end */
-       if (!list_empty_careful(&log->l_reserveq)) {
-               spin_lock(&log->l_grant_reserve_lock);
-               /* recheck the queue now we are locked */
-               if (list_empty(&log->l_reserveq)) {
-                       spin_unlock(&log->l_grant_reserve_lock);
-                       goto redo;
-               }
-               list_add_tail(&tic->t_queue, &log->l_reserveq);
-
-               trace_xfs_log_grant_sleep1(log, tic);
-
-               /*
-                * Gotta check this before going to sleep, while we're
-                * holding the grant lock.
-                */
-               if (XLOG_FORCED_SHUTDOWN(log))
-                       goto error_return;
-
-               XFS_STATS_INC(xs_sleep_logspace);
-               xlog_wait(&tic->t_wait, &log->l_grant_reserve_lock);
-
-               /*
-                * If we got an error, and the filesystem is shutting down,
-                * we'll catch it down below. So just continue...
-                */
-               trace_xfs_log_grant_wake1(log, tic);
-       }
-
-redo:
-       if (XLOG_FORCED_SHUTDOWN(log))
-               goto error_return_unlocked;
-
        free_bytes = xlog_space_left(log, &log->l_grant_reserve_head);
-       if (free_bytes < need_bytes) {
+       if (!list_empty_careful(&log->l_reserveq)) {
                spin_lock(&log->l_grant_reserve_lock);
-               if (list_empty(&tic->t_queue))
-                       list_add_tail(&tic->t_queue, &log->l_reserveq);
-
-               trace_xfs_log_grant_sleep2(log, tic);
-
-               if (XLOG_FORCED_SHUTDOWN(log))
-                       goto error_return;
-
-               xlog_grant_push_ail(log, need_bytes);
-
-               XFS_STATS_INC(xs_sleep_logspace);
-               xlog_wait(&tic->t_wait, &log->l_grant_reserve_lock);
-
-               trace_xfs_log_grant_wake2(log, tic);
-               goto redo;
-       }
-
-       if (!list_empty(&tic->t_queue)) {
+               if (!xlog_reserveq_wake(log, &free_bytes) ||
+                   free_bytes < need_bytes)
+                       error = xlog_reserveq_wait(log, tic, need_bytes);
+               spin_unlock(&log->l_grant_reserve_lock);
+       } else if (free_bytes < need_bytes) {
                spin_lock(&log->l_grant_reserve_lock);
-               list_del_init(&tic->t_queue);
+               error = xlog_reserveq_wait(log, tic, need_bytes);
                spin_unlock(&log->l_grant_reserve_lock);
        }
+       if (error)
+               return error;
 
-       /* we've got enough space */
        xlog_grant_add_space(log, &log->l_grant_reserve_head, need_bytes);
        xlog_grant_add_space(log, &log->l_grant_write_head, need_bytes);
        trace_xfs_log_grant_exit(log, tic);
        xlog_verify_grant_tail(log);
        return 0;
-
-error_return_unlocked:
-       spin_lock(&log->l_grant_reserve_lock);
-error_return:
-       list_del_init(&tic->t_queue);
-       spin_unlock(&log->l_grant_reserve_lock);
-       trace_xfs_log_grant_error(log, tic);
-
-       /*
-        * If we are failing, make sure the ticket doesn't have any
-        * current reservations. We don't want to add this back when
-        * the ticket/transaction gets cancelled.
-        */
-       tic->t_curr_res = 0;
-       tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
-       return XFS_ERROR(EIO);
-}      /* xlog_grant_log_space */
-
+}
 
 /*
  * Replenish the byte reservation required by moving the grant write head.
@@ -2605,10 +2667,12 @@ error_return:
  * free fast path.
  */
 STATIC int
-xlog_regrant_write_log_space(xlog_t       *log,
-                            xlog_ticket_t *tic)
+xlog_regrant_write_log_space(
+       struct log              *log,
+       struct xlog_ticket      *tic)
 {
-       int             free_bytes, need_bytes;
+       int                     free_bytes, need_bytes;
+       int                     error = 0;
 
        tic->t_curr_res = tic->t_unit_res;
        xlog_tic_reset_res(tic);
@@ -2616,104 +2680,38 @@ xlog_regrant_write_log_space(xlog_t       *log,
        if (tic->t_cnt > 0)
                return 0;
 
-#ifdef DEBUG
-       if (log->l_flags & XLOG_ACTIVE_RECOVERY)
-               panic("regrant Recovery problem");
-#endif
+       ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
 
        trace_xfs_log_regrant_write_enter(log, tic);
-       if (XLOG_FORCED_SHUTDOWN(log))
-               goto error_return_unlocked;
 
-       /* If there are other waiters on the queue then give them a
-        * chance at logspace before us. Wake up the first waiters,
-        * if we do not wake up all the waiters then go to sleep waiting
-        * for more free space, otherwise try to get some space for
-        * this transaction.
+       /*
+        * If there are other waiters on the queue then give them a chance at
+        * logspace before us.  Wake up the first waiters, if we do not wake
+        * up all the waiters then go to sleep waiting for more free space,
+        * otherwise try to get some space for this transaction.
         */
        need_bytes = tic->t_unit_res;
-       if (!list_empty_careful(&log->l_writeq)) {
-               struct xlog_ticket *ntic;
-
-               spin_lock(&log->l_grant_write_lock);
-               free_bytes = xlog_space_left(log, &log->l_grant_write_head);
-               list_for_each_entry(ntic, &log->l_writeq, t_queue) {
-                       ASSERT(ntic->t_flags & XLOG_TIC_PERM_RESERV);
-
-                       if (free_bytes < ntic->t_unit_res)
-                               break;
-                       free_bytes -= ntic->t_unit_res;
-                       wake_up(&ntic->t_wait);
-               }
-
-               if (ntic != list_first_entry(&log->l_writeq,
-                                               struct xlog_ticket, t_queue)) {
-                       if (list_empty(&tic->t_queue))
-                               list_add_tail(&tic->t_queue, &log->l_writeq);
-                       trace_xfs_log_regrant_write_sleep1(log, tic);
-
-                       xlog_grant_push_ail(log, need_bytes);
-
-                       XFS_STATS_INC(xs_sleep_logspace);
-                       xlog_wait(&tic->t_wait, &log->l_grant_write_lock);
-                       trace_xfs_log_regrant_write_wake1(log, tic);
-               } else
-                       spin_unlock(&log->l_grant_write_lock);
-       }
-
-redo:
-       if (XLOG_FORCED_SHUTDOWN(log))
-               goto error_return_unlocked;
-
        free_bytes = xlog_space_left(log, &log->l_grant_write_head);
-       if (free_bytes < need_bytes) {
+       if (!list_empty_careful(&log->l_writeq)) {
                spin_lock(&log->l_grant_write_lock);
-               if (list_empty(&tic->t_queue))
-                       list_add_tail(&tic->t_queue, &log->l_writeq);
-
-               if (XLOG_FORCED_SHUTDOWN(log))
-                       goto error_return;
-
-               xlog_grant_push_ail(log, need_bytes);
-
-               XFS_STATS_INC(xs_sleep_logspace);
-               trace_xfs_log_regrant_write_sleep2(log, tic);
-               xlog_wait(&tic->t_wait, &log->l_grant_write_lock);
-
-               trace_xfs_log_regrant_write_wake2(log, tic);
-               goto redo;
-       }
-
-       if (!list_empty(&tic->t_queue)) {
+               if (!xlog_writeq_wake(log, &free_bytes) ||
+                   free_bytes < need_bytes)
+                       error = xlog_writeq_wait(log, tic, need_bytes);
+               spin_unlock(&log->l_grant_write_lock);
+       } else if (free_bytes < need_bytes) {
                spin_lock(&log->l_grant_write_lock);
-               list_del_init(&tic->t_queue);
+               error = xlog_writeq_wait(log, tic, need_bytes);
                spin_unlock(&log->l_grant_write_lock);
        }
 
-       /* we've got enough space */
+       if (error)
+               return error;
+
        xlog_grant_add_space(log, &log->l_grant_write_head, need_bytes);
        trace_xfs_log_regrant_write_exit(log, tic);
        xlog_verify_grant_tail(log);
        return 0;
-
-
- error_return_unlocked:
-       spin_lock(&log->l_grant_write_lock);
- error_return:
-       list_del_init(&tic->t_queue);
-       spin_unlock(&log->l_grant_write_lock);
-       trace_xfs_log_regrant_write_error(log, tic);
-
-       /*
-        * If we are failing, make sure the ticket doesn't have any
-        * current reservations. We don't want to add this back when
-        * the ticket/transaction gets cancelled.
-        */
-       tic->t_curr_res = 0;
-       tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
-       return XFS_ERROR(EIO);
-}      /* xlog_regrant_write_log_space */
-
+}
 
 /* The first cnt-1 times through here we don't need to
  * move the grant write head because the permanent