Merge branch 'sh/sdio' into sh-latest

1 files changed, 335 insertions, 404 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index cee4ab9f8a9e..0bf24b11d0c4 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -47,7 +47,7 @@ STATIC xlog_t *  xlog_alloc_log(xfs_mount_t	*mp,
                                 xfs_buftarg_t   *log_target,
                                 xfs_daddr_t     blk_offset,
                                 int             num_bblks);
-STATIC int       xlog_space_left(xlog_t *log, int cycle, int bytes);
+STATIC int       xlog_space_left(struct log *log, atomic64_t *head);
 STATIC int       xlog_sync(xlog_t *log, xlog_in_core_t *iclog);
 STATIC void      xlog_dealloc_log(xlog_t *log);
 
@@ -70,7 +70,7 @@ STATIC void xlog_state_want_sync(xlog_t	*log, xlog_in_core_t *iclog);
 /* local functions to manipulate grant head */
 STATIC int  xlog_grant_log_space(xlog_t         *log,
                                  xlog_ticket_t  *xtic);
-STATIC void xlog_grant_push_ail(xfs_mount_t     *mp,
+STATIC void xlog_grant_push_ail(struct log      *log,
                                 int             need_bytes);
 STATIC void xlog_regrant_reserve_log_space(xlog_t        *log,
                                            xlog_ticket_t *ticket);
@@ -81,98 +81,73 @@ STATIC void xlog_ungrant_log_space(xlog_t	 *log,
 
 #if defined(DEBUG)
 STATIC void     xlog_verify_dest_ptr(xlog_t *log, char *ptr);
-STATIC void     xlog_verify_grant_head(xlog_t *log, int equals);
+STATIC void     xlog_verify_grant_tail(struct log *log);
 STATIC void     xlog_verify_iclog(xlog_t *log, xlog_in_core_t *iclog,
                                   int count, boolean_t syncing);
 STATIC void     xlog_verify_tail_lsn(xlog_t *log, xlog_in_core_t *iclog,
                                      xfs_lsn_t tail_lsn);
 #else
 #define xlog_verify_dest_ptr(a,b)
-#define xlog_verify_grant_head(a,b)
+#define xlog_verify_grant_tail(a)
 #define xlog_verify_iclog(a,b,c,d)
 #define xlog_verify_tail_lsn(a,b,c)
 #endif
 
 STATIC int      xlog_iclogs_empty(xlog_t *log);
 
-
 static void
-xlog_ins_ticketq(struct xlog_ticket **qp, struct xlog_ticket *tic)
+xlog_grant_sub_space(
+        struct log      *log,
+        atomic64_t      *head,
+        int             bytes)
 {
-        if (*qp) {
-                tic->t_next         = (*qp);
-                tic->t_prev         = (*qp)->t_prev;
-                (*qp)->t_prev->t_next = tic;
-                (*qp)->t_prev       = tic;
-        } else {
-                tic->t_prev = tic->t_next = tic;
-                *qp = tic;
-        }
+        int64_t head_val = atomic64_read(head);
+        int64_t new, old;
 
-        tic->t_flags |= XLOG_TIC_IN_Q;
-}
+        do {
+                int     cycle, space;
 
-static void
-xlog_del_ticketq(struct xlog_ticket **qp, struct xlog_ticket *tic)
-{
-        if (tic == tic->t_next) {
-                *qp = NULL;
-        } else {
-                *qp = tic->t_next;
-                tic->t_next->t_prev = tic->t_prev;
-                tic->t_prev->t_next = tic->t_next;
-        }
+                xlog_crack_grant_head_val(head_val, &cycle, &space);
 
-        tic->t_next = tic->t_prev = NULL;
-        tic->t_flags &= ~XLOG_TIC_IN_Q;
+                space -= bytes;
+                if (space < 0) {
+                        space += log->l_logsize;
+                        cycle--;
+                }
+
+                old = head_val;
+                new = xlog_assign_grant_head_val(cycle, space);
+                head_val = atomic64_cmpxchg(head, old, new);
+        } while (head_val != old);
 }
 
 static void
-xlog_grant_sub_space(struct log *log, int bytes)
+xlog_grant_add_space(
+        struct log      *log,
+        atomic64_t      *head,
+        int             bytes)
 {
-        log->l_grant_write_bytes -= bytes;
-        if (log->l_grant_write_bytes < 0) {
-                log->l_grant_write_bytes += log->l_logsize;
-                log->l_grant_write_cycle--;
-        }
-
-        log->l_grant_reserve_bytes -= bytes;
-        if ((log)->l_grant_reserve_bytes < 0) {
-                log->l_grant_reserve_bytes += log->l_logsize;
-                log->l_grant_reserve_cycle--;
-        }
+        int64_t head_val = atomic64_read(head);
+        int64_t new, old;
 
-}
+        do {
+                int             tmp;
+                int             cycle, space;
 
-static void
-xlog_grant_add_space_write(struct log *log, int bytes)
-{
-        int tmp = log->l_logsize - log->l_grant_write_bytes;
-        if (tmp > bytes)
-                log->l_grant_write_bytes += bytes;
-        else {
-                log->l_grant_write_cycle++;
-                log->l_grant_write_bytes = bytes - tmp;
-        }
-}
+                xlog_crack_grant_head_val(head_val, &cycle, &space);
 
-static void
-xlog_grant_add_space_reserve(struct log *log, int bytes)
-{
-        int tmp = log->l_logsize - log->l_grant_reserve_bytes;
-        if (tmp > bytes)
-                log->l_grant_reserve_bytes += bytes;
-        else {
-                log->l_grant_reserve_cycle++;
-                log->l_grant_reserve_bytes = bytes - tmp;
-        }
-}
+                tmp = log->l_logsize - space;
+                if (tmp > bytes)
+                        space += bytes;
+                else {
+                        space = bytes - tmp;
+                        cycle++;
+                }
 
-static inline void
-xlog_grant_add_space(struct log *log, int bytes)
-{
-        xlog_grant_add_space_write(log, bytes);
-        xlog_grant_add_space_reserve(log, bytes);
+                old = head_val;
+                new = xlog_assign_grant_head_val(cycle, space);
+                head_val = atomic64_cmpxchg(head, old, new);
+        } while (head_val != old);
 }
 
 static void
@@ -355,7 +330,7 @@ xfs_log_reserve(
 
                 trace_xfs_log_reserve(log, internal_ticket);
 
-                xlog_grant_push_ail(mp, internal_ticket->t_unit_res);
+                xlog_grant_push_ail(log, internal_ticket->t_unit_res);
                 retval = xlog_regrant_write_log_space(log, internal_ticket);
         } else {
                 /* may sleep if need to allocate more tickets */
@@ -369,7 +344,7 @@ xfs_log_reserve(
 
                 trace_xfs_log_reserve(log, internal_ticket);
 
-                xlog_grant_push_ail(mp,
+                xlog_grant_push_ail(log,
                                     (internal_ticket->t_unit_res *
                                      internal_ticket->t_cnt));
                 retval = xlog_grant_log_space(log, internal_ticket);
@@ -584,8 +559,8 @@ xfs_log_unmount_write(xfs_mount_t *mp)
                 if (!(iclog->ic_state == XLOG_STATE_ACTIVE ||
                       iclog->ic_state == XLOG_STATE_DIRTY)) {
                         if (!XLOG_FORCED_SHUTDOWN(log)) {
-                                sv_wait(&iclog->ic_force_wait, PMEM,
-                                        &log->l_icloglock, s);
+                                xlog_wait(&iclog->ic_force_wait,
+                                                        &log->l_icloglock);
                         } else {
                                 spin_unlock(&log->l_icloglock);
                         }
@@ -625,8 +600,8 @@ xfs_log_unmount_write(xfs_mount_t *mp)
                         || iclog->ic_state == XLOG_STATE_DIRTY
                         || iclog->ic_state == XLOG_STATE_IOERROR) ) {
 
-                                sv_wait(&iclog->ic_force_wait, PMEM,
-                                        &log->l_icloglock, s);
+                                xlog_wait(&iclog->ic_force_wait,
+                                                        &log->l_icloglock);
                 } else {
                         spin_unlock(&log->l_icloglock);
                 }
@@ -703,55 +678,46 @@ xfs_log_move_tail(xfs_mount_t	*mp,
 {
         xlog_ticket_t   *tic;
         xlog_t          *log = mp->m_log;
-        int             need_bytes, free_bytes, cycle, bytes;
+        int             need_bytes, free_bytes;
 
         if (XLOG_FORCED_SHUTDOWN(log))
                 return;
 
-        if (tail_lsn == 0) {
-                /* needed since sync_lsn is 64 bits */
-                spin_lock(&log->l_icloglock);
-                tail_lsn = log->l_last_sync_lsn;
-                spin_unlock(&log->l_icloglock);
-        }
-
-        spin_lock(&log->l_grant_lock);
+        if (tail_lsn == 0)
+                tail_lsn = atomic64_read(&log->l_last_sync_lsn);
 
-        /* Also an invalid lsn.  1 implies that we aren't passing in a valid
-         * tail_lsn.
-         */
-        if (tail_lsn != 1) {
-                log->l_tail_lsn = tail_lsn;
-        }
+        /* tail_lsn == 1 implies that we weren't passed a valid value.  */
+        if (tail_lsn != 1)
+                atomic64_set(&log->l_tail_lsn, tail_lsn);
 
-        if ((tic = log->l_write_headq)) {
+        if (!list_empty_careful(&log->l_writeq)) {
 #ifdef DEBUG
                 if (log->l_flags & XLOG_ACTIVE_RECOVERY)
                         panic("Recovery problem");
 #endif
-                cycle = log->l_grant_write_cycle;
-                bytes = log->l_grant_write_bytes;
-                free_bytes = xlog_space_left(log, cycle, bytes);
-                do {
+                spin_lock(&log->l_grant_write_lock);
+                free_bytes = xlog_space_left(log, &log->l_grant_write_head);
+                list_for_each_entry(tic, &log->l_writeq, t_queue) {
                         ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
 
                         if (free_bytes < tic->t_unit_res && tail_lsn != 1)
                                 break;
                         tail_lsn = 0;
                         free_bytes -= tic->t_unit_res;
-                        sv_signal(&tic->t_wait);
-                        tic = tic->t_next;
-                } while (tic != log->l_write_headq);
+                        trace_xfs_log_regrant_write_wake_up(log, tic);
+                        wake_up(&tic->t_wait);
+                }
+                spin_unlock(&log->l_grant_write_lock);
         }
-        if ((tic = log->l_reserve_headq)) {
+
+        if (!list_empty_careful(&log->l_reserveq)) {
 #ifdef DEBUG
                 if (log->l_flags & XLOG_ACTIVE_RECOVERY)
                         panic("Recovery problem");
 #endif
-                cycle = log->l_grant_reserve_cycle;
-                bytes = log->l_grant_reserve_bytes;
-                free_bytes = xlog_space_left(log, cycle, bytes);
-                do {
+                spin_lock(&log->l_grant_reserve_lock);
+                free_bytes = xlog_space_left(log, &log->l_grant_reserve_head);
+                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
@@ -760,12 +726,12 @@ xfs_log_move_tail(xfs_mount_t	*mp,
                                 break;
                         tail_lsn = 0;
                         free_bytes -= need_bytes;
-                        sv_signal(&tic->t_wait);
-                        tic = tic->t_next;
-                } while (tic != log->l_reserve_headq);
+                        trace_xfs_log_grant_wake_up(log, tic);
+                        wake_up(&tic->t_wait);
+                }
+                spin_unlock(&log->l_grant_reserve_lock);
         }
-        spin_unlock(&log->l_grant_lock);
-}       /* xfs_log_move_tail */
+}
 
 /*
  * Determine if we have a transaction that has gone to disk
@@ -831,23 +797,19 @@ xfs_log_need_covered(xfs_mount_t *mp)
  * We may be holding the log iclog lock upon entering this routine.
  */
 xfs_lsn_t
-xlog_assign_tail_lsn(xfs_mount_t *mp)
+xlog_assign_tail_lsn(
+        struct xfs_mount        *mp)
 {
-        xfs_lsn_t tail_lsn;
-        xlog_t    *log = mp->m_log;
+        xfs_lsn_t               tail_lsn;
+        struct log              *log = mp->m_log;
 
         tail_lsn = xfs_trans_ail_tail(mp->m_ail);
-        spin_lock(&log->l_grant_lock);
-        if (tail_lsn != 0) {
-                log->l_tail_lsn = tail_lsn;
-        } else {
-                tail_lsn = log->l_tail_lsn = log->l_last_sync_lsn;
-        }
-        spin_unlock(&log->l_grant_lock);
+        if (!tail_lsn)
+                tail_lsn = atomic64_read(&log->l_last_sync_lsn);
 
+        atomic64_set(&log->l_tail_lsn, tail_lsn);
         return tail_lsn;
-}       /* xlog_assign_tail_lsn */
-
+}
 
 /*
  * Return the space in the log between the tail and the head.  The head
@@ -864,21 +826,26 @@ xlog_assign_tail_lsn(xfs_mount_t *mp)
  * result is that we return the size of the log as the amount of space left.
  */
 STATIC int
-xlog_space_left(xlog_t *log, int cycle, int bytes)
-{
-        int free_bytes;
-        int tail_bytes;
-        int tail_cycle;
-
-        tail_bytes = BBTOB(BLOCK_LSN(log->l_tail_lsn));
-        tail_cycle = CYCLE_LSN(log->l_tail_lsn);
-        if ((tail_cycle == cycle) && (bytes >= tail_bytes)) {
-                free_bytes = log->l_logsize - (bytes - tail_bytes);
-        } else if ((tail_cycle + 1) < cycle) {
+xlog_space_left(
+        struct log      *log,
+        atomic64_t      *head)
+{
+        int             free_bytes;
+        int             tail_bytes;
+        int             tail_cycle;
+        int             head_cycle;
+        int             head_bytes;
+
+        xlog_crack_grant_head(head, &head_cycle, &head_bytes);
+        xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
+        tail_bytes = BBTOB(tail_bytes);
+        if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
+                free_bytes = log->l_logsize - (head_bytes - tail_bytes);
+        else if (tail_cycle + 1 < head_cycle)
                 return 0;
-        } else if (tail_cycle < cycle) {
-                ASSERT(tail_cycle == (cycle - 1));
-                free_bytes = tail_bytes - bytes;
+        else if (tail_cycle < head_cycle) {
+                ASSERT(tail_cycle == (head_cycle - 1));
+                free_bytes = tail_bytes - head_bytes;
         } else {
                 /*
                  * The reservation head is behind the tail.
@@ -889,12 +856,12 @@ xlog_space_left(xlog_t *log, int cycle, int bytes)
                         "xlog_space_left: head behind tail\n"
                         "  tail_cycle = %d, tail_bytes = %d\n"
                         "  GH   cycle = %d, GH   bytes = %d",
-                        tail_cycle, tail_bytes, cycle, bytes);
+                        tail_cycle, tail_bytes, head_cycle, head_bytes);
                 ASSERT(0);
                 free_bytes = log->l_logsize;
         }
         return free_bytes;
-}       /* xlog_space_left */
+}
 
 
 /*
@@ -1047,12 +1014,16 @@ xlog_alloc_log(xfs_mount_t	*mp,
         log->l_flags       |= XLOG_ACTIVE_RECOVERY;
 
         log->l_prev_block  = -1;
-        log->l_tail_lsn    = xlog_assign_lsn(1, 0);
         /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
-        log->l_last_sync_lsn = log->l_tail_lsn;
+        xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
+        xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
         log->l_curr_cycle  = 1;     /* 0 is bad since this is initial value */
-        log->l_grant_reserve_cycle = 1;
-        log->l_grant_write_cycle = 1;
+        xlog_assign_grant_head(&log->l_grant_reserve_head, 1, 0);
+        xlog_assign_grant_head(&log->l_grant_write_head, 1, 0);
+        INIT_LIST_HEAD(&log->l_reserveq);
+        INIT_LIST_HEAD(&log->l_writeq);
+        spin_lock_init(&log->l_grant_reserve_lock);
+        spin_lock_init(&log->l_grant_write_lock);
 
         error = EFSCORRUPTED;
         if (xfs_sb_version_hassector(&mp->m_sb)) {
@@ -1094,8 +1065,7 @@ xlog_alloc_log(xfs_mount_t	*mp,
         log->l_xbuf = bp;
 
         spin_lock_init(&log->l_icloglock);
-        spin_lock_init(&log->l_grant_lock);
-        sv_init(&log->l_flush_wait, 0, "flush_wait");
+        init_waitqueue_head(&log->l_flush_wait);
 
         /* log record size must be multiple of BBSIZE; see xlog_rec_header_t */
         ASSERT((XFS_BUF_SIZE(bp) & BBMASK) == 0);
@@ -1151,8 +1121,8 @@ xlog_alloc_log(xfs_mount_t	*mp,
 
                 ASSERT(XFS_BUF_ISBUSY(iclog->ic_bp));
                 ASSERT(XFS_BUF_VALUSEMA(iclog->ic_bp) <= 0);
-                sv_init(&iclog->ic_force_wait, SV_DEFAULT, "iclog-force");
-                sv_init(&iclog->ic_write_wait, SV_DEFAULT, "iclog-write");
+                init_waitqueue_head(&iclog->ic_force_wait);
+                init_waitqueue_head(&iclog->ic_write_wait);
 
                 iclogp = &iclog->ic_next;
         }
@@ -1167,15 +1137,11 @@ xlog_alloc_log(xfs_mount_t	*mp,
 out_free_iclog:
         for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
                 prev_iclog = iclog->ic_next;
-                if (iclog->ic_bp) {
-                        sv_destroy(&iclog->ic_force_wait);
-                        sv_destroy(&iclog->ic_write_wait);
+                if (iclog->ic_bp)
                         xfs_buf_free(iclog->ic_bp);
-                }
                 kmem_free(iclog);
         }
         spinlock_destroy(&log->l_icloglock);
-        spinlock_destroy(&log->l_grant_lock);
         xfs_buf_free(log->l_xbuf);
 out_free_log:
         kmem_free(log);
@@ -1223,61 +1189,60 @@ xlog_commit_record(
  * water mark.  In this manner, we would be creating a low water mark.
  */
 STATIC void
-xlog_grant_push_ail(xfs_mount_t *mp,
-                    int         need_bytes)
+xlog_grant_push_ail(
+        struct log      *log,
+        int             need_bytes)
 {
-    xlog_t      *log = mp->m_log;       /* pointer to the log */
-    xfs_lsn_t   tail_lsn;               /* lsn of the log tail */
-    xfs_lsn_t   threshold_lsn = 0;      /* lsn we'd like to be at */
-    int         free_blocks;            /* free blocks left to write to */
-    int         free_bytes;             /* free bytes left to write to */
-    int         threshold_block;        /* block in lsn we'd like to be at */
-    int         threshold_cycle;        /* lsn cycle we'd like to be at */
-    int         free_threshold;
-
-    ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
-
-    spin_lock(&log->l_grant_lock);
-    free_bytes = xlog_space_left(log,
-                                 log->l_grant_reserve_cycle,
-                                 log->l_grant_reserve_bytes);
-    tail_lsn = log->l_tail_lsn;
-    free_blocks = BTOBBT(free_bytes);
-
-    /*
-     * Set the threshold for the minimum number of free blocks in the
-     * log to the maximum of what the caller needs, one quarter of the
-     * log, and 256 blocks.
-     */
-    free_threshold = BTOBB(need_bytes);
-    free_threshold = MAX(free_threshold, (log->l_logBBsize >> 2));
-    free_threshold = MAX(free_threshold, 256);
-    if (free_blocks < free_threshold) {
-        threshold_block = BLOCK_LSN(tail_lsn) + free_threshold;
-        threshold_cycle = CYCLE_LSN(tail_lsn);
+        xfs_lsn_t       threshold_lsn = 0;
+        xfs_lsn_t       last_sync_lsn;
+        int             free_blocks;
+        int             free_bytes;
+        int             threshold_block;
+        int             threshold_cycle;
+        int             free_threshold;
+
+        ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
+
+        free_bytes = xlog_space_left(log, &log->l_grant_reserve_head);
+        free_blocks = BTOBBT(free_bytes);
+
+        /*
+         * Set the threshold for the minimum number of free blocks in the
+         * log to the maximum of what the caller needs, one quarter of the
+         * log, and 256 blocks.
+         */
+        free_threshold = BTOBB(need_bytes);
+        free_threshold = MAX(free_threshold, (log->l_logBBsize >> 2));
+        free_threshold = MAX(free_threshold, 256);
+        if (free_blocks >= free_threshold)
+                return;
+
+        xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
+                                                &threshold_block);
+        threshold_block += free_threshold;
         if (threshold_block >= log->l_logBBsize) {
-            threshold_block -= log->l_logBBsize;
-            threshold_cycle += 1;
+                threshold_block -= log->l_logBBsize;
+                threshold_cycle += 1;
         }
-        threshold_lsn = xlog_assign_lsn(threshold_cycle, threshold_block);
+        threshold_lsn = xlog_assign_lsn(threshold_cycle,
+                                        threshold_block);
+        /*
+         * Don't pass in an lsn greater than the lsn of the last
+         * log record known to be on disk. Use a snapshot of the last sync lsn
+         * so that it doesn't change between the compare and the set.
+         */
+        last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
+        if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
+                threshold_lsn = last_sync_lsn;
 
-        /* Don't pass in an lsn greater than the lsn of the last
-         * log record known to be on disk.
+        /*
+         * Get the transaction layer to kick the dirty buffers out to
+         * disk asynchronously. No point in trying to do this if
+         * the filesystem is shutting down.
          */
-        if (XFS_LSN_CMP(threshold_lsn, log->l_last_sync_lsn) > 0)
-            threshold_lsn = log->l_last_sync_lsn;
-    }
-    spin_unlock(&log->l_grant_lock);
-
-    /*
-     * Get the transaction layer to kick the dirty buffers out to
-     * disk asynchronously. No point in trying to do this if
-     * the filesystem is shutting down.
-     */
-    if (threshold_lsn &&
-        !XLOG_FORCED_SHUTDOWN(log))
-            xfs_trans_ail_push(log->l_ailp, threshold_lsn);
-}       /* xlog_grant_push_ail */
+        if (!XLOG_FORCED_SHUTDOWN(log))
+                xfs_trans_ail_push(log->l_ailp, threshold_lsn);
+}
 
 /*
  * The bdstrat callback function for log bufs. This gives us a central
@@ -1372,9 +1337,8 @@ xlog_sync(xlog_t		*log,
                  roundoff < BBTOB(1)));
 
         /* move grant heads by roundoff in sync */
-        spin_lock(&log->l_grant_lock);
-        xlog_grant_add_space(log, roundoff);
-        spin_unlock(&log->l_grant_lock);
+        xlog_grant_add_space(log, &log->l_grant_reserve_head, roundoff);
+        xlog_grant_add_space(log, &log->l_grant_write_head, roundoff);
 
         /* put cycle number in every block */
         xlog_pack_data(log, iclog, roundoff); 
@@ -1489,15 +1453,12 @@ xlog_dealloc_log(xlog_t *log)
 
         iclog = log->l_iclog;
         for (i=0; i<log->l_iclog_bufs; i++) {
-                sv_destroy(&iclog->ic_force_wait);
-                sv_destroy(&iclog->ic_write_wait);
                 xfs_buf_free(iclog->ic_bp);
                 next_iclog = iclog->ic_next;
                 kmem_free(iclog);
                 iclog = next_iclog;
         }
         spinlock_destroy(&log->l_icloglock);
-        spinlock_destroy(&log->l_grant_lock);
 
         xfs_buf_free(log->l_xbuf);
         log->l_mp->m_log = NULL;
@@ -2232,7 +2193,7 @@ xlog_state_do_callback(
                                 lowest_lsn = xlog_get_lowest_lsn(log);
                                 if (lowest_lsn &&
                                     XFS_LSN_CMP(lowest_lsn,
-                                                be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
+                                                be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
                                         iclog = iclog->ic_next;
                                         continue; /* Leave this iclog for
                                                    * another thread */
@@ -2240,23 +2201,21 @@ xlog_state_do_callback(
 
                                 iclog->ic_state = XLOG_STATE_CALLBACK;
 
-                                spin_unlock(&log->l_icloglock);
 
-                                /* l_last_sync_lsn field protected by
-                                 * l_grant_lock. Don't worry about iclog's lsn.
-                                 * No one else can be here except us.
+                                /*
+                                 * update the last_sync_lsn before we drop the
+                                 * icloglock to ensure we are the only one that
+                                 * can update it.
                                  */
-                                spin_lock(&log->l_grant_lock);
-                                ASSERT(XFS_LSN_CMP(log->l_last_sync_lsn,
-                                       be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
-                                log->l_last_sync_lsn =
-                                        be64_to_cpu(iclog->ic_header.h_lsn);
-                                spin_unlock(&log->l_grant_lock);
+                                ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
+                                        be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
+                                atomic64_set(&log->l_last_sync_lsn,
+                                        be64_to_cpu(iclog->ic_header.h_lsn));
 
-                        } else {
-                                spin_unlock(&log->l_icloglock);
+                        } else
                                 ioerrors++;
-                        }
+
+                        spin_unlock(&log->l_icloglock);
 
                         /*
                          * Keep processing entries in the callback list until
@@ -2297,7 +2256,7 @@ xlog_state_do_callback(
                         xlog_state_clean_log(log);
 
                         /* wake up threads waiting in xfs_log_force() */
-                        sv_broadcast(&iclog->ic_force_wait);
+                        wake_up_all(&iclog->ic_force_wait);
 
                         iclog = iclog->ic_next;
                 } while (first_iclog != iclog);
@@ -2344,7 +2303,7 @@ xlog_state_do_callback(
         spin_unlock(&log->l_icloglock);
 
         if (wake)
-                sv_broadcast(&log->l_flush_wait);
+                wake_up_all(&log->l_flush_wait);
 }
 
 
@@ -2395,7 +2354,7 @@ xlog_state_done_syncing(
          * iclog buffer, we wake them all, one will get to do the
          * I/O, the others get to wait for the result.
          */
-        sv_broadcast(&iclog->ic_write_wait);
+        wake_up_all(&iclog->ic_write_wait);
         spin_unlock(&log->l_icloglock);
         xlog_state_do_callback(log, aborted, iclog);    /* also cleans log */
 }       /* xlog_state_done_syncing */
@@ -2444,7 +2403,7 @@ restart:
                 XFS_STATS_INC(xs_log_noiclogs);
 
                 /* Wait for log writes to have flushed */
-                sv_wait(&log->l_flush_wait, 0, &log->l_icloglock, 0);
+                xlog_wait(&log->l_flush_wait, &log->l_icloglock);
                 goto restart;
         }
 
@@ -2527,6 +2486,18 @@ restart:
  *
  * 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
+ * path. Hence any lock will be globally hot if we take it unconditionally on
+ * 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.
  */
 STATIC int
 xlog_grant_log_space(xlog_t        *log,
@@ -2534,24 +2505,27 @@ xlog_grant_log_space(xlog_t	   *log,
 {
         int              free_bytes;
         int              need_bytes;
-#ifdef DEBUG
-        xfs_lsn_t        tail_lsn;
-#endif
-
 
 #ifdef DEBUG
         if (log->l_flags & XLOG_ACTIVE_RECOVERY)
                 panic("grant Recovery problem");
 #endif
 
-        /* Is there space or do we need to sleep? */
-        spin_lock(&log->l_grant_lock);
-
         trace_xfs_log_grant_enter(log, tic);
 
+        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 (log->l_reserve_headq) {
-                xlog_ins_ticketq(&log->l_reserve_headq, tic);
+        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);
 
@@ -2563,72 +2537,57 @@ xlog_grant_log_space(xlog_t	   *log,
                         goto error_return;
 
                 XFS_STATS_INC(xs_sleep_logspace);
-                sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
+                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);
-                spin_lock(&log->l_grant_lock);
         }
-        if (tic->t_flags & XFS_LOG_PERM_RESERV)
-                need_bytes = tic->t_unit_res*tic->t_ocnt;
-        else
-                need_bytes = tic->t_unit_res;
 
 redo:
         if (XLOG_FORCED_SHUTDOWN(log))
-                goto error_return;
+                goto error_return_unlocked;
 
-        free_bytes = xlog_space_left(log, log->l_grant_reserve_cycle,
-                                     log->l_grant_reserve_bytes);
+        free_bytes = xlog_space_left(log, &log->l_grant_reserve_head);
         if (free_bytes < need_bytes) {
-                if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
-                        xlog_ins_ticketq(&log->l_reserve_headq, tic);
+                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);
 
-                spin_unlock(&log->l_grant_lock);
-                xlog_grant_push_ail(log->l_mp, need_bytes);
-                spin_lock(&log->l_grant_lock);
-
-                XFS_STATS_INC(xs_sleep_logspace);
-                sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
-
-                spin_lock(&log->l_grant_lock);
                 if (XLOG_FORCED_SHUTDOWN(log))
                         goto error_return;
 
-                trace_xfs_log_grant_wake2(log, tic);
+                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;
-        } else if (tic->t_flags & XLOG_TIC_IN_Q)
-                xlog_del_ticketq(&log->l_reserve_headq, tic);
+        }
 
-        /* we've got enough space */
-        xlog_grant_add_space(log, need_bytes);
-#ifdef DEBUG
-        tail_lsn = log->l_tail_lsn;
-        /*
-         * Check to make sure the grant write head didn't just over lap the
-         * tail.  If the cycles are the same, we can't be overlapping.
-         * Otherwise, make sure that the cycles differ by exactly one and
-         * check the byte count.
-         */
-        if (CYCLE_LSN(tail_lsn) != log->l_grant_write_cycle) {
-                ASSERT(log->l_grant_write_cycle-1 == CYCLE_LSN(tail_lsn));
-                ASSERT(log->l_grant_write_bytes <= BBTOB(BLOCK_LSN(tail_lsn)));
+        if (!list_empty(&tic->t_queue)) {
+                spin_lock(&log->l_grant_reserve_lock);
+                list_del_init(&tic->t_queue);
+                spin_unlock(&log->l_grant_reserve_lock);
         }
-#endif
+
+        /* 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_head(log, 1);
-        spin_unlock(&log->l_grant_lock);
+        xlog_verify_grant_tail(log);
         return 0;
 
- error_return:
-        if (tic->t_flags & XLOG_TIC_IN_Q)
-                xlog_del_ticketq(&log->l_reserve_headq, tic);
-
+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);
 
         /*
@@ -2638,7 +2597,6 @@ redo:
          */
         tic->t_curr_res = 0;
         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
-        spin_unlock(&log->l_grant_lock);
         return XFS_ERROR(EIO);
 }       /* xlog_grant_log_space */
 
@@ -2646,17 +2604,14 @@ redo:
 /*
  * Replenish the byte reservation required by moving the grant write head.
  *
- *
+ * Similar to xlog_grant_log_space, the function is structured to have a lock
+ * free fast path.
  */
 STATIC int
 xlog_regrant_write_log_space(xlog_t        *log,
                              xlog_ticket_t *tic)
 {
         int             free_bytes, need_bytes;
-        xlog_ticket_t   *ntic;
-#ifdef DEBUG
-        xfs_lsn_t       tail_lsn;
-#endif
 
         tic->t_curr_res = tic->t_unit_res;
         xlog_tic_reset_res(tic);
@@ -2669,12 +2624,9 @@ xlog_regrant_write_log_space(xlog_t	   *log,
                 panic("regrant Recovery problem");
 #endif
 
-        spin_lock(&log->l_grant_lock);
-
         trace_xfs_log_regrant_write_enter(log, tic);
-
         if (XLOG_FORCED_SHUTDOWN(log))
-                goto error_return;
+                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,
@@ -2683,92 +2635,76 @@ xlog_regrant_write_log_space(xlog_t	   *log,
          * this transaction.
          */
         need_bytes = tic->t_unit_res;
-        if ((ntic = log->l_write_headq)) {
-                free_bytes = xlog_space_left(log, log->l_grant_write_cycle,
-                                             log->l_grant_write_bytes);
-                do {
+        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;
-                        sv_signal(&ntic->t_wait);
-                        ntic = ntic->t_next;
-                } while (ntic != log->l_write_headq);
-
-                if (ntic != log->l_write_headq) {
-                        if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
-                                xlog_ins_ticketq(&log->l_write_headq, tic);
+                        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);
 
-                        spin_unlock(&log->l_grant_lock);
-                        xlog_grant_push_ail(log->l_mp, need_bytes);
-                        spin_lock(&log->l_grant_lock);
+                        xlog_grant_push_ail(log, need_bytes);
 
                         XFS_STATS_INC(xs_sleep_logspace);
-                        sv_wait(&tic->t_wait, PINOD|PLTWAIT,
-                                &log->l_grant_lock, s);
-
-                        /* If we're shutting down, this tic is already
-                         * off the queue */
-                        spin_lock(&log->l_grant_lock);
-                        if (XLOG_FORCED_SHUTDOWN(log))
-                                goto error_return;
-
+                        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;
+                goto error_return_unlocked;
 
-        free_bytes = xlog_space_left(log, log->l_grant_write_cycle,
-                                     log->l_grant_write_bytes);
+        free_bytes = xlog_space_left(log, &log->l_grant_write_head);
         if (free_bytes < need_bytes) {
-                if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
-                        xlog_ins_ticketq(&log->l_write_headq, tic);
-                spin_unlock(&log->l_grant_lock);
-                xlog_grant_push_ail(log->l_mp, need_bytes);
-                spin_lock(&log->l_grant_lock);
-
-                XFS_STATS_INC(xs_sleep_logspace);
-                trace_xfs_log_regrant_write_sleep2(log, tic);
-
-                sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
+                spin_lock(&log->l_grant_write_lock);
+                if (list_empty(&tic->t_queue))
+                        list_add_tail(&tic->t_queue, &log->l_writeq);
 
-                /* If we're shutting down, this tic is already off the queue */
-                spin_lock(&log->l_grant_lock);
                 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;
-        } else if (tic->t_flags & XLOG_TIC_IN_Q)
-                xlog_del_ticketq(&log->l_write_headq, tic);
+        }
 
-        /* we've got enough space */
-        xlog_grant_add_space_write(log, need_bytes);
-#ifdef DEBUG
-        tail_lsn = log->l_tail_lsn;
-        if (CYCLE_LSN(tail_lsn) != log->l_grant_write_cycle) {
-                ASSERT(log->l_grant_write_cycle-1 == CYCLE_LSN(tail_lsn));
-                ASSERT(log->l_grant_write_bytes <= BBTOB(BLOCK_LSN(tail_lsn)));
+        if (!list_empty(&tic->t_queue)) {
+                spin_lock(&log->l_grant_write_lock);
+                list_del_init(&tic->t_queue);
+                spin_unlock(&log->l_grant_write_lock);
         }
-#endif
 
+        /* we've got enough space */
+        xlog_grant_add_space(log, &log->l_grant_write_head, need_bytes);
         trace_xfs_log_regrant_write_exit(log, tic);
-
-        xlog_verify_grant_head(log, 1);
-        spin_unlock(&log->l_grant_lock);
+        xlog_verify_grant_tail(log);
         return 0;
 
 
+ error_return_unlocked:
+        spin_lock(&log->l_grant_write_lock);
  error_return:
-        if (tic->t_flags & XLOG_TIC_IN_Q)
-                xlog_del_ticketq(&log->l_reserve_headq, tic);
-
+        list_del_init(&tic->t_queue);
+        spin_unlock(&log->l_grant_write_lock);
         trace_xfs_log_regrant_write_error(log, tic);
 
         /*
@@ -2778,7 +2714,6 @@ redo:
          */
         tic->t_curr_res = 0;
         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
-        spin_unlock(&log->l_grant_lock);
         return XFS_ERROR(EIO);
 }       /* xlog_regrant_write_log_space */
 
@@ -2799,27 +2734,24 @@ xlog_regrant_reserve_log_space(xlog_t	     *log,
         if (ticket->t_cnt > 0)
                 ticket->t_cnt--;
 
-        spin_lock(&log->l_grant_lock);
-        xlog_grant_sub_space(log, ticket->t_curr_res);
+        xlog_grant_sub_space(log, &log->l_grant_reserve_head,
+                                        ticket->t_curr_res);
+        xlog_grant_sub_space(log, &log->l_grant_write_head,
+                                        ticket->t_curr_res);
         ticket->t_curr_res = ticket->t_unit_res;
         xlog_tic_reset_res(ticket);
 
         trace_xfs_log_regrant_reserve_sub(log, ticket);
 
-        xlog_verify_grant_head(log, 1);
-
         /* just return if we still have some of the pre-reserved space */
-        if (ticket->t_cnt > 0) {
-                spin_unlock(&log->l_grant_lock);
+        if (ticket->t_cnt > 0)
                 return;
-        }
 
-        xlog_grant_add_space_reserve(log, ticket->t_unit_res);
+        xlog_grant_add_space(log, &log->l_grant_reserve_head,
+                                        ticket->t_unit_res);
 
         trace_xfs_log_regrant_reserve_exit(log, ticket);
 
-        xlog_verify_grant_head(log, 0);
-        spin_unlock(&log->l_grant_lock);
         ticket->t_curr_res = ticket->t_unit_res;
         xlog_tic_reset_res(ticket);
 }       /* xlog_regrant_reserve_log_space */
@@ -2843,28 +2775,29 @@ STATIC void
 xlog_ungrant_log_space(xlog_t        *log,
                        xlog_ticket_t *ticket)
 {
+        int     bytes;
+
         if (ticket->t_cnt > 0)
                 ticket->t_cnt--;
 
-        spin_lock(&log->l_grant_lock);
         trace_xfs_log_ungrant_enter(log, ticket);
-
-        xlog_grant_sub_space(log, ticket->t_curr_res);
-
         trace_xfs_log_ungrant_sub(log, ticket);
 
-        /* If this is a permanent reservation ticket, we may be able to free
+        /*
+         * If this is a permanent reservation ticket, we may be able to free
          * up more space based on the remaining count.
          */
+        bytes = ticket->t_curr_res;
         if (ticket->t_cnt > 0) {
                 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
-                xlog_grant_sub_space(log, ticket->t_unit_res*ticket->t_cnt);
+                bytes += ticket->t_unit_res*ticket->t_cnt;
         }
 
+        xlog_grant_sub_space(log, &log->l_grant_reserve_head, bytes);
+        xlog_grant_sub_space(log, &log->l_grant_write_head, bytes);
+
         trace_xfs_log_ungrant_exit(log, ticket);
 
-        xlog_verify_grant_head(log, 1);
-        spin_unlock(&log->l_grant_lock);
         xfs_log_move_tail(log->l_mp, 1);
 }       /* xlog_ungrant_log_space */
 
@@ -2901,11 +2834,11 @@ xlog_state_release_iclog(
 
         if (iclog->ic_state == XLOG_STATE_WANT_SYNC) {
                 /* update tail before writing to iclog */
-                xlog_assign_tail_lsn(log->l_mp);
+                xfs_lsn_t tail_lsn = xlog_assign_tail_lsn(log->l_mp);
                 sync++;
                 iclog->ic_state = XLOG_STATE_SYNCING;
-                iclog->ic_header.h_tail_lsn = cpu_to_be64(log->l_tail_lsn);
-                xlog_verify_tail_lsn(log, iclog, log->l_tail_lsn);
+                iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
+                xlog_verify_tail_lsn(log, iclog, tail_lsn);
                 /* cycle incremented when incrementing curr_block */
         }
         spin_unlock(&log->l_icloglock);
@@ -3088,7 +3021,7 @@ maybe_sleep:
                         return XFS_ERROR(EIO);
                 }
                 XFS_STATS_INC(xs_log_force_sleep);
-                sv_wait(&iclog->ic_force_wait, PINOD, &log->l_icloglock, s);
+                xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
                 /*
                  * No need to grab the log lock here since we're
                  * only deciding whether or not to return EIO
@@ -3206,8 +3139,8 @@ try_again:
 
                                 XFS_STATS_INC(xs_log_force_sleep);
 
-                                sv_wait(&iclog->ic_prev->ic_write_wait,
-                                        PSWP, &log->l_icloglock, s);
+                                xlog_wait(&iclog->ic_prev->ic_write_wait,
+                                                        &log->l_icloglock);
                                 if (log_flushed)
                                         *log_flushed = 1;
                                 already_slept = 1;
@@ -3235,7 +3168,7 @@ try_again:
                                 return XFS_ERROR(EIO);
                         }
                         XFS_STATS_INC(xs_log_force_sleep);
-                        sv_wait(&iclog->ic_force_wait, PSWP, &log->l_icloglock, s);
+                        xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
                         /*
                          * No need to grab the log lock here since we're
                          * only deciding whether or not to return EIO
@@ -3310,10 +3243,8 @@ xfs_log_ticket_put(
         xlog_ticket_t   *ticket)
 {
         ASSERT(atomic_read(&ticket->t_ref) > 0);
-        if (atomic_dec_and_test(&ticket->t_ref)) {
-                sv_destroy(&ticket->t_wait);
+        if (atomic_dec_and_test(&ticket->t_ref))
                 kmem_zone_free(xfs_log_ticket_zone, ticket);
-        }
 }
 
 xlog_ticket_t *
@@ -3435,6 +3366,7 @@ xlog_ticket_alloc(
         }
 
         atomic_set(&tic->t_ref, 1);
+        INIT_LIST_HEAD(&tic->t_queue);
         tic->t_unit_res         = unit_bytes;
         tic->t_curr_res         = unit_bytes;
         tic->t_cnt              = cnt;
@@ -3445,7 +3377,7 @@ xlog_ticket_alloc(
         tic->t_trans_type       = 0;
         if (xflags & XFS_LOG_PERM_RESERV)
                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
-        sv_init(&tic->t_wait, SV_DEFAULT, "logtick");
+        init_waitqueue_head(&tic->t_wait);
 
         xlog_tic_reset_res(tic);
 
@@ -3484,18 +3416,25 @@ xlog_verify_dest_ptr(
 }
 
 STATIC void
-xlog_verify_grant_head(xlog_t *log, int equals)
+xlog_verify_grant_tail(
+        struct log      *log)
 {
-    if (log->l_grant_reserve_cycle == log->l_grant_write_cycle) {
-        if (equals)
-            ASSERT(log->l_grant_reserve_bytes >= log->l_grant_write_bytes);
-        else
-            ASSERT(log->l_grant_reserve_bytes > log->l_grant_write_bytes);
-    } else {
-        ASSERT(log->l_grant_reserve_cycle-1 == log->l_grant_write_cycle);
-        ASSERT(log->l_grant_write_bytes >= log->l_grant_reserve_bytes);
-    }
-}       /* xlog_verify_grant_head */
+        int             tail_cycle, tail_blocks;
+        int             cycle, space;
+
+        /*
+         * Check to make sure the grant write head didn't just over lap the
+         * tail.  If the cycles are the same, we can't be overlapping.
+         * Otherwise, make sure that the cycles differ by exactly one and
+         * check the byte count.
+         */
+        xlog_crack_grant_head(&log->l_grant_write_head, &cycle, &space);
+        xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
+        if (tail_cycle != cycle) {
+                ASSERT(cycle - 1 == tail_cycle);
+                ASSERT(space <= BBTOB(tail_blocks));
+        }
+}
 
 /* check if it will fit */
 STATIC void
@@ -3716,12 +3655,10 @@ xfs_log_force_umount(
                 xlog_cil_force(log);
 
         /*
-         * We must hold both the GRANT lock and the LOG lock,
-         * before we mark the filesystem SHUTDOWN and wake
-         * everybody up to tell the bad news.
+         * mark the filesystem and the as in a shutdown state and wake
+         * everybody up to tell them the bad news.
          */
         spin_lock(&log->l_icloglock);
-        spin_lock(&log->l_grant_lock);
         mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
         if (mp->m_sb_bp)
                 XFS_BUF_DONE(mp->m_sb_bp);
@@ -3742,27 +3679,21 @@ xfs_log_force_umount(
         spin_unlock(&log->l_icloglock);
 
         /*
-         * We don't want anybody waiting for log reservations
-         * after this. That means we have to wake up everybody
-         * queued up on reserve_headq as well as write_headq.
-         * In addition, we make sure in xlog_{re}grant_log_space
-         * that we don't enqueue anything once the SHUTDOWN flag
-         * is set, and this action is protected by the GRANTLOCK.
+         * We don't want anybody waiting for log reservations after this. That
+         * means we have to wake up everybody queued up on reserveq as well as
+         * writeq.  In addition, we make sure in xlog_{re}grant_log_space that
+         * we don't enqueue anything once the SHUTDOWN flag is set, and this
+         * action is protected by the grant locks.
          */
-        if ((tic = log->l_reserve_headq)) {
-                do {
-                        sv_signal(&tic->t_wait);
-                        tic = tic->t_next;
-                } while (tic != log->l_reserve_headq);
-        }
-
-        if ((tic = log->l_write_headq)) {
-                do {
-                        sv_signal(&tic->t_wait);
-                        tic = tic->t_next;
-                } while (tic != log->l_write_headq);
-        }
-        spin_unlock(&log->l_grant_lock);
+        spin_lock(&log->l_grant_reserve_lock);
+        list_for_each_entry(tic, &log->l_reserveq, t_queue)
+                wake_up(&tic->t_wait);
+        spin_unlock(&log->l_grant_reserve_lock);
+
+        spin_lock(&log->l_grant_write_lock);
+        list_for_each_entry(tic, &log->l_writeq, t_queue)
+                wake_up(&tic->t_wait);
+        spin_unlock(&log->l_grant_write_lock);
 
         if (!(log->l_iclog->ic_state & XLOG_STATE_IOERROR)) {
                 ASSERT(!logerror);