diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index 3ff6b35f92072b1fe1c0d96fc357fbaea06198d7..b180e1bf8257a0f1fce9da0e7c62b2284e21ee54 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -794,7 +794,7 @@ DECLARE_EVENT_CLASS(xfs_loggrant_class,
&__entry->grant_write_bytes);
__entry->curr_cycle = log->l_curr_cycle;
__entry->curr_block = log->l_curr_block;
- __entry->tail_lsn = log->l_tail_lsn;
+ __entry->tail_lsn = atomic64_read(&log->l_tail_lsn);
),
TP_printk("dev %d:%d type %s t_ocnt %u t_cnt %u t_curr_res %u "
"t_unit_res %u t_flags %s reserveq %s "
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 70790eb48336b78a683192338ae36efc3ef392d5..d118bf8044809734d75c77a99244014062ecebc6 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -678,15 +678,11 @@ xfs_log_move_tail(xfs_mount_t *mp,
if (tail_lsn == 0)
tail_lsn = atomic64_read(&log->l_last_sync_lsn);
- spin_lock(&log->l_grant_lock);
-
- /* 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);
+ spin_lock(&log->l_grant_lock);
if (!list_empty(&log->l_writeq)) {
#ifdef DEBUG
if (log->l_flags & XLOG_ACTIVE_RECOVERY)
@@ -789,21 +785,19 @@ 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)
tail_lsn = atomic64_read(&log->l_last_sync_lsn);
- log->l_tail_lsn = tail_lsn;
- spin_unlock(&log->l_grant_lock);
+ 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
@@ -831,8 +825,8 @@ xlog_space_left(
int head_bytes;
xlog_crack_grant_head(head, &head_cycle, &head_bytes);
- tail_bytes = BBTOB(BLOCK_LSN(log->l_tail_lsn));
- tail_cycle = CYCLE_LSN(log->l_tail_lsn);
+ 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)
@@ -1009,8 +1003,8 @@ xlog_alloc_log(xfs_mount_t *mp,
log->l_prev_block = -1;
/* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
- log->l_tail_lsn = xlog_assign_lsn(1, 0);
- atomic64_set(&log->l_last_sync_lsn, xlog_assign_lsn(1, 0));
+ 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 */
xlog_assign_grant_head(&log->l_grant_reserve_head, 1, 0);
xlog_assign_grant_head(&log->l_grant_write_head, 1, 0);
@@ -1189,7 +1183,6 @@ xlog_grant_push_ail(
{
xfs_lsn_t threshold_lsn = 0;
xfs_lsn_t last_sync_lsn;
- xfs_lsn_t tail_lsn;
int free_blocks;
int free_bytes;
int threshold_block;
@@ -1198,7 +1191,6 @@ xlog_grant_push_ail(
ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
- tail_lsn = log->l_tail_lsn;
free_bytes = xlog_space_left(log, &log->l_grant_reserve_head);
free_blocks = BTOBBT(free_bytes);
@@ -1213,8 +1205,9 @@ xlog_grant_push_ail(
if (free_blocks >= free_threshold)
return;
- threshold_block = BLOCK_LSN(tail_lsn) + free_threshold;
- threshold_cycle = CYCLE_LSN(tail_lsn);
+ 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;
@@ -2828,11 +2821,11 @@ 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);
@@ -3435,7 +3428,7 @@ STATIC void
xlog_verify_grant_tail(
struct log *log)
{
- xfs_lsn_t tail_lsn = log->l_tail_lsn;
+ int tail_cycle, tail_blocks;
int cycle, space;
/*
@@ -3445,9 +3438,10 @@ xlog_verify_grant_tail(
* check the byte count.
*/
xlog_crack_grant_head(&log->l_grant_write_head, &cycle, &space);
- if (CYCLE_LSN(tail_lsn) != cycle) {
- ASSERT(cycle - 1 == CYCLE_LSN(tail_lsn));
- ASSERT(space <= BBTOB(BLOCK_LSN(tail_lsn)));
+ 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));
}
}
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index 958f356df10ed51cb6c33297554adc127c3b7657..d34af1c21ed275036e94594853d2d5827c54f8ac 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -53,7 +53,6 @@ struct xfs_mount;
BTOBB(XLOG_MAX_ICLOGS << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))
-
static inline xfs_lsn_t xlog_assign_lsn(uint cycle, uint block)
{
return ((xfs_lsn_t)cycle << 32) | block;
@@ -505,8 +504,6 @@ typedef struct log {
* log entries" */
xlog_in_core_t *l_iclog; /* head log queue */
spinlock_t l_icloglock; /* grab to change iclog state */
- xfs_lsn_t l_tail_lsn; /* lsn of 1st LR with unflushed
- * buffers */
int l_curr_cycle; /* Cycle number of log writes */
int l_prev_cycle; /* Cycle number before last
* block increment */
@@ -521,12 +518,15 @@ typedef struct log {
int64_t l_grant_write_head;
/*
- * l_last_sync_lsn is an atomic so it can be set and read without
- * needing to hold specific locks. To avoid operations contending with
- * other hot objects, place it on a separate cacheline.
+ * l_last_sync_lsn and l_tail_lsn are atomics so they can be set and
+ * read without needing to hold specific locks. To avoid operations
+ * contending with other hot objects, place each of them on a separate
+ * cacheline.
*/
/* lsn of last LR on disk */
atomic64_t l_last_sync_lsn ____cacheline_aligned_in_smp;
+ /* lsn of 1st LR with unflushed * buffers */
+ atomic64_t l_tail_lsn ____cacheline_aligned_in_smp;
/* The following field are used for debugging; need to hold icloglock */
#ifdef DEBUG
@@ -565,6 +565,31 @@ int xlog_write(struct log *log, struct xfs_log_vec *log_vector,
struct xlog_ticket *tic, xfs_lsn_t *start_lsn,
xlog_in_core_t **commit_iclog, uint flags);
+/*
+ * When we crack an atomic LSN, we sample it first so that the value will not
+ * change while we are cracking it into the component values. This means we
+ * will always get consistent component values to work from. This should always
+ * be used to smaple and crack LSNs taht are stored and updated in atomic
+ * variables.
+ */
+static inline void
+xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block)
+{
+ xfs_lsn_t val = atomic64_read(lsn);
+
+ *cycle = CYCLE_LSN(val);
+ *block = BLOCK_LSN(val);
+}
+
+/*
+ * Calculate and assign a value to an atomic LSN variable from component pieces.
+ */
+static inline void
+xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block)
+{
+ atomic64_set(lsn, xlog_assign_lsn(cycle, block));
+}
+
/*
* When we crack the grrant head, we sample it first so that the value will not
* change while we are cracking it into the component values. This means we
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 18e1e18d7147173731df2a279f7fd43313016454..204d8e5fa7faf63ada5fc2135fefc2b7330d34ec 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -936,7 +936,7 @@ xlog_find_tail(
log->l_curr_cycle = be32_to_cpu(rhead->h_cycle);
if (found == 2)
log->l_curr_cycle++;
- log->l_tail_lsn = be64_to_cpu(rhead->h_tail_lsn);
+ atomic64_set(&log->l_tail_lsn, be64_to_cpu(rhead->h_tail_lsn));
atomic64_set(&log->l_last_sync_lsn, be64_to_cpu(rhead->h_lsn));
xlog_assign_grant_head(&log->l_grant_reserve_head, log->l_curr_cycle,
BBTOB(log->l_curr_block));
@@ -971,7 +971,7 @@ xlog_find_tail(
}
after_umount_blk = (i + hblks + (int)
BTOBB(be32_to_cpu(rhead->h_len))) % log->l_logBBsize;
- tail_lsn = log->l_tail_lsn;
+ tail_lsn = atomic64_read(&log->l_tail_lsn);
if (*head_blk == after_umount_blk &&
be32_to_cpu(rhead->h_num_logops) == 1) {
umount_data_blk = (i + hblks) % log->l_logBBsize;
@@ -986,12 +986,10 @@ xlog_find_tail(
* log records will point recovery to after the
* current unmount record.
*/
- log->l_tail_lsn =
- xlog_assign_lsn(log->l_curr_cycle,
- after_umount_blk);
- atomic64_set(&log->l_last_sync_lsn,
- xlog_assign_lsn(log->l_curr_cycle,
- after_umount_blk));
+ xlog_assign_atomic_lsn(&log->l_tail_lsn,
+ log->l_curr_cycle, after_umount_blk);
+ xlog_assign_atomic_lsn(&log->l_last_sync_lsn,
+ log->l_curr_cycle, after_umount_blk);
*tail_blk = after_umount_blk;
/*