xfs: split and cleanup xfs_log_reserve

Split the log regrant case out of xfs_log_reserve into a separate function,
and merge xlog_grant_log_space and xlog_regrant_write_log_space into their
respective callers.  Also replace the XFS_LOG_PERM_RESERV flag, which easily
got misused before the previous cleanups with a simple boolean parameter.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

5 files changed, 151 insertions, 170 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index c6a29a05c60a..98a9cb5ffd17 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -67,15 +67,10 @@ STATIC void xlog_state_switch_iclogs(xlog_t		*log,
                                      int                eventual_size);
 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(struct log      *log,
                                 int             need_bytes);
 STATIC void xlog_regrant_reserve_log_space(xlog_t        *log,
                                            xlog_ticket_t *ticket);
-STATIC int xlog_regrant_write_log_space(xlog_t          *log,
-                                         xlog_ticket_t  *ticket);
 STATIC void xlog_ungrant_log_space(xlog_t        *log,
                                    xlog_ticket_t *ticket);
 
@@ -324,6 +319,128 @@ xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
 }
 
 /*
+ * Replenish the byte reservation required by moving the grant write head.
+ */
+int
+xfs_log_regrant(
+        struct xfs_mount        *mp,
+        struct xlog_ticket      *tic)
+{
+        struct log              *log = mp->m_log;
+        int                     need_bytes;
+        int                     error = 0;
+
+        if (XLOG_FORCED_SHUTDOWN(log))
+                return XFS_ERROR(EIO);
+
+        XFS_STATS_INC(xs_try_logspace);
+
+        /*
+         * This is a new transaction on the ticket, so we need to change the
+         * transaction ID so that the next transaction has a different TID in
+         * the log. Just add one to the existing tid so that we can see chains
+         * of rolling transactions in the log easily.
+         */
+        tic->t_tid++;
+
+        xlog_grant_push_ail(log, tic->t_unit_res);
+
+        tic->t_curr_res = tic->t_unit_res;
+        xlog_tic_reset_res(tic);
+
+        if (tic->t_cnt > 0)
+                return 0;
+
+        trace_xfs_log_regrant(log, tic);
+
+        error = xlog_grant_head_check(log, &log->l_write_head, tic,
+                                      &need_bytes);
+        if (error)
+                goto out_error;
+
+        xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
+        trace_xfs_log_regrant_exit(log, tic);
+        xlog_verify_grant_tail(log);
+        return 0;
+
+out_error:
+        /*
+         * 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 error;
+}
+
+/*
+ * Reserve log space and return a ticket corresponding the reservation.
+ *
+ * Each reservation is going to reserve extra space for a log record header.
+ * When writes happen to the on-disk log, we don't subtract the length of the
+ * log record header from any reservation.  By wasting space in each
+ * reservation, we prevent over allocation problems.
+ */
+int
+xfs_log_reserve(
+        struct xfs_mount        *mp,
+        int                     unit_bytes,
+        int                     cnt,
+        struct xlog_ticket      **ticp,
+        __uint8_t               client,
+        bool                    permanent,
+        uint                    t_type)
+{
+        struct log              *log = mp->m_log;
+        struct xlog_ticket      *tic;
+        int                     need_bytes;
+        int                     error = 0;
+
+        ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
+
+        if (XLOG_FORCED_SHUTDOWN(log))
+                return XFS_ERROR(EIO);
+
+        XFS_STATS_INC(xs_try_logspace);
+
+        ASSERT(*ticp == NULL);
+        tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent,
+                                KM_SLEEP | KM_MAYFAIL);
+        if (!tic)
+                return XFS_ERROR(ENOMEM);
+
+        tic->t_trans_type = t_type;
+        *ticp = tic;
+
+        xlog_grant_push_ail(log, tic->t_unit_res * tic->t_cnt);
+
+        trace_xfs_log_reserve(log, tic);
+
+        error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
+                                      &need_bytes);
+        if (error)
+                goto out_error;
+
+        xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
+        xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
+        trace_xfs_log_reserve_exit(log, tic);
+        xlog_verify_grant_tail(log);
+        return 0;
+
+out_error:
+        /*
+         * 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 error;
+}
+
+
+/*
  * NOTES:
  *
  *      1. currblock field gets updated at startup and after in-core logs
@@ -433,88 +550,6 @@ xfs_log_release_iclog(
 }
 
 /*
- *  1. Reserve an amount of on-disk log space and return a ticket corresponding
- *      to the reservation.
- *  2. Potentially, push buffers at tail of log to disk.
- *
- * Each reservation is going to reserve extra space for a log record header.
- * When writes happen to the on-disk log, we don't subtract the length of the
- * log record header from any reservation.  By wasting space in each
- * reservation, we prevent over allocation problems.
- */
-int
-xfs_log_reserve(
-        struct xfs_mount        *mp,
-        int                     unit_bytes,
-        int                     cnt,
-        struct xlog_ticket      **ticket,
-        __uint8_t               client,
-        uint                    flags,
-        uint                    t_type)
-{
-        struct log              *log = mp->m_log;
-        struct xlog_ticket      *internal_ticket;
-        int                     retval = 0;
-
-        ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
-
-        if (XLOG_FORCED_SHUTDOWN(log))
-                return XFS_ERROR(EIO);
-
-        XFS_STATS_INC(xs_try_logspace);
-
-
-        if (*ticket != NULL) {
-                ASSERT(flags & XFS_LOG_PERM_RESERV);
-                internal_ticket = *ticket;
-
-                /*
-                 * this is a new transaction on the ticket, so we need to
-                 * change the transaction ID so that the next transaction has a
-                 * different TID in the log. Just add one to the existing tid
-                 * so that we can see chains of rolling transactions in the log
-                 * easily.
-                 */
-                internal_ticket->t_tid++;
-
-                trace_xfs_log_reserve(log, internal_ticket);
-
-                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 */
-                internal_ticket = xlog_ticket_alloc(log, unit_bytes, cnt,
-                                                  client, flags,
-                                                  KM_SLEEP|KM_MAYFAIL);
-                if (!internal_ticket)
-                        return XFS_ERROR(ENOMEM);
-                internal_ticket->t_trans_type = t_type;
-                *ticket = internal_ticket;
-
-                trace_xfs_log_reserve(log, internal_ticket);
-
-                xlog_grant_push_ail(log,
-                                    (internal_ticket->t_unit_res *
-                                     internal_ticket->t_cnt));
-                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;
-}
-
-
-/*
  * Mount a log filesystem
  *
  * mp           - ubiquitous xfs mount point structure
@@ -2565,58 +2600,6 @@ restart:
         return 0;
 }       /* xlog_state_get_iclog_space */
 
-STATIC int
-xlog_grant_log_space(
-        struct log              *log,
-        struct xlog_ticket      *tic)
-{
-        int                     need_bytes;
-        int                     error = 0;
-
-        trace_xfs_log_grant_enter(log, tic);
-
-        error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
-                                      &need_bytes);
-        if (error)
-                return error;
-
-        xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
-        xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
-        trace_xfs_log_grant_exit(log, tic);
-        xlog_verify_grant_tail(log);
-        return 0;
-}
-
-/*
- * Replenish the byte reservation required by moving the grant write head.
- */
-STATIC int
-xlog_regrant_write_log_space(
-        struct log              *log,
-        struct xlog_ticket      *tic)
-{
-        int                     need_bytes;
-        int                     error = 0;
-
-        tic->t_curr_res = tic->t_unit_res;
-        xlog_tic_reset_res(tic);
-
-        if (tic->t_cnt > 0)
-                return 0;
-
-        trace_xfs_log_regrant_write_enter(log, tic);
-
-        error = xlog_grant_head_check(log, &log->l_write_head, tic,
-                                      &need_bytes);
-        if (error)
-                return error;
-
-        xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
-        trace_xfs_log_regrant_write_exit(log, tic);
-        xlog_verify_grant_tail(log);
-        return 0;
-}
-
 /* The first cnt-1 times through here we don't need to
  * move the grant write head because the permanent
  * reservation has reserved cnt times the unit amount.
@@ -3156,7 +3139,7 @@ xlog_ticket_alloc(
         int             unit_bytes,
         int             cnt,
         char            client,
-        uint            xflags,
+        bool            permanent,
         int             alloc_flags)
 {
         struct xlog_ticket *tic;
@@ -3260,7 +3243,7 @@ xlog_ticket_alloc(
         tic->t_clientid         = client;
         tic->t_flags            = XLOG_TIC_INITED;
         tic->t_trans_type       = 0;
-        if (xflags & XFS_LOG_PERM_RESERV)
+        if (permanent)
                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
 
         xlog_tic_reset_res(tic);
diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
index fe32c6927877..2c622bedb302 100644
--- a/fs/xfs/xfs_log.h
+++ b/fs/xfs/xfs_log.h
@@ -53,15 +53,6 @@ static inline xfs_lsn_t	_lsn_cmp(xfs_lsn_t lsn1, xfs_lsn_t lsn2)
 #define XFS_LOG_REL_PERM_RESERV 0x1
 
 /*
- * Flags to xfs_log_reserve()
- *
- *      XFS_LOG_PERM_RESERV: Permanent reservation.  When writes are
- *              performed against this type of reservation, the reservation
- *              is not decreased.  Long running transactions should use this.
- */
-#define XFS_LOG_PERM_RESERV     0x2
-
-/*
  * Flags to xfs_log_force()
  *
  *      XFS_LOG_SYNC:   Synchronous force in-core log to disk
@@ -172,8 +163,9 @@ int	  xfs_log_reserve(struct xfs_mount *mp,
                           int              count,
                           struct xlog_ticket **ticket,
                           __uint8_t        clientid,
-                          uint             flags,
+                          bool             permanent,
                           uint             t_type);
+int       xfs_log_regrant(struct xfs_mount *mp, struct xlog_ticket *tic);
 int       xfs_log_unmount_write(struct xfs_mount *mp);
 void      xfs_log_unmount(struct xfs_mount *mp);
 int       xfs_log_force_umount(struct xfs_mount *mp, int logerror);
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index eba4ec925a45..2152900b79d4 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -552,7 +552,7 @@ extern void	 xlog_pack_data(xlog_t *log, xlog_in_core_t *iclog, int);
 
 extern kmem_zone_t *xfs_log_ticket_zone;
 struct xlog_ticket *xlog_ticket_alloc(struct log *log, int unit_bytes,
-                                int count, char client, uint xflags,
+                                int count, char client, bool permanent,
                                 int alloc_flags);
 
 
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 482bebf8c7ef..3b369c1277f0 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -826,17 +826,14 @@ DEFINE_EVENT(xfs_loggrant_class, name, \
         TP_ARGS(log, tic))
 DEFINE_LOGGRANT_EVENT(xfs_log_done_nonperm);
 DEFINE_LOGGRANT_EVENT(xfs_log_done_perm);
-DEFINE_LOGGRANT_EVENT(xfs_log_reserve);
 DEFINE_LOGGRANT_EVENT(xfs_log_umount_write);
-DEFINE_LOGGRANT_EVENT(xfs_log_grant_enter);
-DEFINE_LOGGRANT_EVENT(xfs_log_grant_exit);
-DEFINE_LOGGRANT_EVENT(xfs_log_grant_error);
 DEFINE_LOGGRANT_EVENT(xfs_log_grant_sleep);
 DEFINE_LOGGRANT_EVENT(xfs_log_grant_wake);
 DEFINE_LOGGRANT_EVENT(xfs_log_grant_wake_up);
-DEFINE_LOGGRANT_EVENT(xfs_log_regrant_write_enter);
-DEFINE_LOGGRANT_EVENT(xfs_log_regrant_write_exit);
-DEFINE_LOGGRANT_EVENT(xfs_log_regrant_write_error);
+DEFINE_LOGGRANT_EVENT(xfs_log_reserve);
+DEFINE_LOGGRANT_EVENT(xfs_log_reserve_exit);
+DEFINE_LOGGRANT_EVENT(xfs_log_regrant);
+DEFINE_LOGGRANT_EVENT(xfs_log_regrant_exit);
 DEFINE_LOGGRANT_EVENT(xfs_log_regrant_reserve_enter);
 DEFINE_LOGGRANT_EVENT(xfs_log_regrant_reserve_exit);
 DEFINE_LOGGRANT_EVENT(xfs_log_regrant_reserve_sub);
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 7adcdf15ae0c..103b00c90004 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -681,7 +681,6 @@ xfs_trans_reserve(
         uint            flags,
         uint            logcount)
 {
-        int             log_flags;
         int             error = 0;
         int             rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
 
@@ -707,24 +706,32 @@ xfs_trans_reserve(
          * Reserve the log space needed for this transaction.
          */
         if (logspace > 0) {
-                ASSERT((tp->t_log_res == 0) || (tp->t_log_res == logspace));
-                ASSERT((tp->t_log_count == 0) ||
-                        (tp->t_log_count == logcount));
+                bool    permanent = false;
+
+                ASSERT(tp->t_log_res == 0 || tp->t_log_res == logspace);
+                ASSERT(tp->t_log_count == 0 || tp->t_log_count == logcount);
+
                 if (flags & XFS_TRANS_PERM_LOG_RES) {
-                        log_flags = XFS_LOG_PERM_RESERV;
                         tp->t_flags |= XFS_TRANS_PERM_LOG_RES;
+                        permanent = true;
                 } else {
                         ASSERT(tp->t_ticket == NULL);
                         ASSERT(!(tp->t_flags & XFS_TRANS_PERM_LOG_RES));
-                        log_flags = 0;
                 }
 
-                error = xfs_log_reserve(tp->t_mountp, logspace, logcount,
-                                        &tp->t_ticket,
-                                        XFS_TRANSACTION, log_flags, tp->t_type);
-                if (error) {
-                        goto undo_blocks;
+                if (tp->t_ticket != NULL) {
+                        ASSERT(flags & XFS_TRANS_PERM_LOG_RES);
+                        error = xfs_log_regrant(tp->t_mountp, tp->t_ticket);
+                } else {
+                        error = xfs_log_reserve(tp->t_mountp, logspace,
+                                                logcount, &tp->t_ticket,
+                                                XFS_TRANSACTION, permanent,
+                                                tp->t_type);
                 }
+
+                if (error)
+                        goto undo_blocks;
+
                 tp->t_log_res = logspace;
                 tp->t_log_count = logcount;
         }
@@ -752,6 +759,8 @@ xfs_trans_reserve(
          */
 undo_log:
         if (logspace > 0) {
+                int             log_flags;
+
                 if (flags & XFS_TRANS_PERM_LOG_RES) {
                         log_flags = XFS_LOG_REL_PERM_RESERV;
                 } else {