LU-9620 lod: protected ost pool count updation

ASSERTION(iter->lpi_idx <= ((iter->lpi_pool)->pool_obds.op_count)
caused due to reading of ost pool count is not protected in
pool_proc_next and pool_proc_show, pool_proc_show get called when
op_count was zero.

Fix to protect ost pool count by taking lock at start sequence
function pool_proc_start and released lock in pool_proc_stop.
Rather than using down_read / up_read pairs around pool_proc_next
and pool_proc_show, this changes make sure ost pool data gets
protected throughout sequence operation.

Change-Id: I2954496d52dd703b600e69a494898c6266f026bd
Seagate-bug-id: MRP-3629
Signed-off-by: Jadhav Vikram <jadhav.vikram@seagate.com>
Reviewed-by: Ashish Purkar <ashish.purkar@seagate.com>
Tested-by: Elena V. Gryaznova <elena.gryaznova@seagate.com>
Reviewed-by: Vladimir Saveliev <vladimir.saveliev@seagate.com>
Reviewed-on: https://review.whamcloud.com/27506
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/lustre/lod/lod_pool.c b/lustre/lod/lod_pool.c
index 27b945e..df66bb3 100644 (file)
--- a/lustre/lod/lod_pool.c
+++ b/lustre/lod/lod_pool.c
@@ -262,14 +262,11 @@ static void *pool_proc_next(struct seq_file *seq, void *v, loff_t *pos)
 
        /* iterate to find a non empty entry */
        prev_idx = iter->lpi_idx;
-       down_read(&pool_tgt_rw_sem(iter->lpi_pool));
        iter->lpi_idx++;
-       if (iter->lpi_idx == pool_tgt_count(iter->lpi_pool)) {
+       if (iter->lpi_idx >= pool_tgt_count(iter->lpi_pool)) {
                iter->lpi_idx = prev_idx; /* we stay on the last entry */
-               up_read(&pool_tgt_rw_sem(iter->lpi_pool));
                return NULL;
        }
-       up_read(&pool_tgt_rw_sem(iter->lpi_pool));
        (*pos)++;
        /* return != NULL to continue */
        return iter;
@@ -312,6 +309,7 @@ static void *pool_proc_start(struct seq_file *seq, loff_t *pos)
        iter->lpi_idx = 0;
 
        seq->private = iter;
+       down_read(&pool_tgt_rw_sem(pool));
        if (*pos > 0) {
                loff_t i;
                void *ptr;
@@ -346,6 +344,7 @@ static void pool_proc_stop(struct seq_file *seq, void *v)
        struct lod_pool_iterator *iter = seq->private;
 
        if (iter != NULL && iter->lpi_magic == POOL_IT_MAGIC) {
+               up_read(&pool_tgt_rw_sem(iter->lpi_pool));
                seq->private = iter->lpi_pool;
                lod_pool_putref(iter->lpi_pool);
                OBD_FREE_PTR(iter);
@@ -369,9 +368,7 @@ static int pool_proc_show(struct seq_file *seq, void *v)
        LASSERT(iter->lpi_pool != NULL);
        LASSERT(iter->lpi_idx <= pool_tgt_count(iter->lpi_pool));
 
-       down_read(&pool_tgt_rw_sem(iter->lpi_pool));
        tgt = pool_tgt(iter->lpi_pool, iter->lpi_idx);
-       up_read(&pool_tgt_rw_sem(iter->lpi_pool));
        if (tgt != NULL)
                seq_printf(seq, "%s\n", obd_uuid2str(&(tgt->ltd_uuid)));
 

diff --git a/lustre/lov/lov_pool.c b/lustre/lov/lov_pool.c
index 7a2b9ac..08ecfde 100644 (file)
--- a/lustre/lov/lov_pool.c
+++ b/lustre/lov/lov_pool.c
@@ -181,14 +181,11 @@ static void *pool_proc_next(struct seq_file *s, void *v, loff_t *pos)
 
         /* iterate to find a non empty entry */
         prev_idx = iter->idx;
-       down_read(&pool_tgt_rw_sem(iter->pool));
         iter->idx++;
-        if (iter->idx == pool_tgt_count(iter->pool)) {
+       if (iter->idx >= pool_tgt_count(iter->pool)) {
                 iter->idx = prev_idx; /* we stay on the last entry */
-               up_read(&pool_tgt_rw_sem(iter->pool));
                 return NULL;
         }
-       up_read(&pool_tgt_rw_sem(iter->pool));
         (*pos)++;
         /* return != NULL to continue */
         return iter;
@@ -219,6 +216,7 @@ static void *pool_proc_start(struct seq_file *s, loff_t *pos)
          * we can free it at stop() */
         /* /!\ do not forget to restore it to pool before freeing it */
         s->private = iter;
+       down_read(&pool_tgt_rw_sem(pool));
         if (*pos > 0) {
                 loff_t i;
                 void *ptr;
@@ -240,6 +238,7 @@ static void pool_proc_stop(struct seq_file *s, void *v)
          * calling start() method (see seq_read() from fs/seq_file.c)
          * we have to free only if s->private is an iterator */
         if ((iter) && (iter->magic == POOL_IT_MAGIC)) {
+               up_read(&pool_tgt_rw_sem(iter->pool));
                 /* we restore s->private so next call to pool_proc_start()
                  * will work */
                 s->private = iter->pool;
@@ -258,9 +257,7 @@ static int pool_proc_show(struct seq_file *s, void *v)
        LASSERT(iter->pool != NULL);
        LASSERT(iter->idx <= pool_tgt_count(iter->pool));
 
-       down_read(&pool_tgt_rw_sem(iter->pool));
         tgt = pool_tgt(iter->pool, iter->idx);
-       up_read(&pool_tgt_rw_sem(iter->pool));
         if (tgt)
                 seq_printf(s, "%s\n", obd_uuid2str(&(tgt->ltd_uuid)));