1 files changed, 173 insertions, 175 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index a14cd89fe465..34817adf4b9e 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -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