LU-19106 lod: check QoS data in pool before down_write

Just like ltd_qos_is_usable() does, define pool_qos_is_usable()
to check whether QoS data in pool is up-to-date and balanced before
expensive qos write lock is taken.

Fixes: e642e75cde02 ("LU-13363 lod: do object allocation in OST pool")
Test-Parameters: ostcount=8 testlist=conf-sanity env=ONLY=133
Signed-off-by: Emoly Liu <emoly@whamcloud.com>
Change-Id: I9d17108b649ba5689f02d5f5eee098d030db3d5b
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/59852
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Tested-by: Shuichi Ihara <sihara@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/lod/lod_qos.c b/lustre/lod/lod_qos.c
index 4a594c4..464ed83 100644 (file)
--- a/lustre/lod/lod_qos.c
+++ b/lustre/lod/lod_qos.c
@@ -1415,6 +1415,18 @@ static void process_semaphore_timer(struct timer_list *t)
 }
 #endif
 
+/* Whether QoS data in pool is up-to-date and balanced. */
+static bool pool_qos_is_usable(struct lod_pool_desc *pool)
+{
+       time64_t now;
+
+       now = ktime_get_real_seconds();
+       if (pool->pool_same_space && now < pool->pool_same_space_expire)
+               return false;
+
+       return true;
+}
+
 /**
  * lod_pool_qos_penalties_calc() - Calculate penalties per-ost in a pool
  * @lod: lod_device
@@ -1444,11 +1456,6 @@ static int lod_pool_qos_penalties_calc(struct lod_device *lod,
 
        ENTRY;
 
-       now = ktime_get_real_seconds();
-
-       if (pool->pool_same_space && now < pool->pool_same_space_expire)
-               GOTO(out, rc = 0);
-
        num_active = osts->op_count - 1;
        if (num_active < 1)
                GOTO(out, rc = -EAGAIN);
@@ -1457,6 +1464,7 @@ static int lod_pool_qos_penalties_calc(struct lod_device *lod,
 
        ba_min = (__u64)(-1);
        ba_max = 0;
+       now = ktime_get_real_seconds();
 
        /* Calculate penalty per OST */
        for (i = 0; i < osts->op_count; i++) {
@@ -1580,17 +1588,18 @@ static int lod_ost_alloc_qos(const struct lu_env *env, struct lod_object *lo,
        if (lod_comp->llc_pool != NULL)
                pool = lod_find_pool(lod, lod_comp->llc_pool);
 
-       if (pool != NULL) {
+       /* Detect -EAGAIN early, before expensive qos write lock is taken. */
+       if (pool) {
                down_read(&pool_tgt_rw_sem(pool));
+               if (!pool_qos_is_usable(pool))
+                       GOTO(out_nolock, rc = -EAGAIN);
                osts = &(pool->pool_obds);
        } else {
+               if (!ltd_qos_is_usable(&lod->lod_ost_descs))
+                       GOTO(out_nolock, rc = -EAGAIN);
                osts = &lod->lod_ost_descs.ltd_tgt_pool;
        }
 
-       /* Detect -EAGAIN early, before expensive lock is taken. */
-       if (!ltd_qos_is_usable(&lod->lod_ost_descs))
-               GOTO(out_nolock, rc = -EAGAIN);
-
        if (lod_comp->llc_pattern & LOV_PATTERN_OVERSTRIPING)
                stripes_per_ost =
                        (lod_comp->llc_stripe_count - 1)/osts->op_count + 1;
@@ -1623,13 +1632,15 @@ static int lod_ost_alloc_qos(const struct lu_env *env, struct lod_object *lo,
         * Check again, while we were sleeping on @lq_rw_sem things could
         * change.
         */
-       if (!ltd_qos_is_usable(&lod->lod_ost_descs))
-               GOTO(out, rc = -EAGAIN);
-
-       if (pool != NULL)
+       if (pool) {
+               if (!pool_qos_is_usable(pool))
+                       GOTO(out, rc = -EAGAIN);
                rc = lod_pool_qos_penalties_calc(lod, pool);
-       else
+       } else {
+               if (!ltd_qos_is_usable(&lod->lod_ost_descs))
+                       GOTO(out, rc = -EAGAIN);
                rc = ltd_qos_penalties_calc(&lod->lod_ost_descs);
+       }
        if (rc)
                GOTO(out, rc);