Allow longer SPA names in stats

The pool name can be 256 chars long. Today, in /proc/spl/kstat/zfs/
the name is limited to < 32 characters. This change is to allows
bigger pool names.

Reviewed-by: Giuseppe Di Natale <[email protected]>
Reviewed-by: loli10K <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: gaurkuma <[email protected]>
Closes #6481 

3 files changed, 22 insertions, 16 deletions

diff --git a/lib/libspl/include/sys/kstat.h b/lib/libspl/include/sys/kstat.h
index fcd3ed98b..24c71e27c 100644
--- a/lib/libspl/include/sys/kstat.h
+++ b/lib/libspl/include/sys/kstat.h
@@ -59,7 +59,7 @@ typedef int	kid_t;		/* unique kstat id */
  *	kcid = ioctl(kd, KSTAT_IOC_WRITE, kstat_t *);
  */
 
-#define	KSTAT_STRLEN	31	/* 30 chars + NULL; must be 16 * n - 1 */
+#define	KSTAT_STRLEN	255	/* 254 chars + NULL; must be 16 * n - 1 */
 
 /*
  * The generic kstat header
diff --git a/module/icp/spi/kcf_spi.c b/module/icp/spi/kcf_spi.c
index c2c2b54bc..0a6e38df8 100644
--- a/module/icp/spi/kcf_spi.c
+++ b/module/icp/spi/kcf_spi.c
@@ -111,7 +111,7 @@ int
 crypto_register_provider(crypto_provider_info_t *info,
     crypto_kcf_provider_handle_t *handle)
 {
-	char ks_name[KSTAT_STRLEN];
+	char *ks_name;
 
 	kcf_provider_desc_t *prov_desc = NULL;
 	int ret = CRYPTO_ARGUMENTS_BAD;
@@ -238,12 +238,12 @@ crypto_register_provider(crypto_provider_info_t *info,
 		 * This kstat is deleted, when the provider unregisters.
 		 */
 		if (prov_desc->pd_prov_type == CRYPTO_SW_PROVIDER) {
-			(void) snprintf(ks_name, KSTAT_STRLEN, "%s_%s",
+			ks_name = kmem_asprintf("%s_%s",
 			    "NONAME", "provider_stats");
 		} else {
-			(void) snprintf(ks_name, KSTAT_STRLEN, "%s_%d_%u_%s",
-			    "NONAME", 0,
-			    prov_desc->pd_prov_id, "provider_stats");
+			ks_name = kmem_asprintf("%s_%d_%u_%s",
+			    "NONAME", 0, prov_desc->pd_prov_id,
+			    "provider_stats");
 		}
 
 		prov_desc->pd_kstat = kstat_create("kcf", 0, ks_name, "crypto",
@@ -261,6 +261,7 @@ crypto_register_provider(crypto_provider_info_t *info,
 			prov_desc->pd_kstat->ks_update = kcf_prov_kstat_update;
 			kstat_install(prov_desc->pd_kstat);
 		}
+		strfree(ks_name);
 	}
 
 	if (prov_desc->pd_prov_type == CRYPTO_HW_PROVIDER)
diff --git a/module/zfs/spa_stats.c b/module/zfs/spa_stats.c
index 7ca359806..8c4dba29e 100644
--- a/module/zfs/spa_stats.c
+++ b/module/zfs/spa_stats.c
@@ -142,7 +142,7 @@ static void
 spa_read_history_init(spa_t *spa)
 {
 	spa_stats_history_t *ssh = &spa->spa_stats.read_history;
-	char name[KSTAT_STRLEN];
+	char *name;
 	kstat_t *ksp;
 
 	mutex_init(&ssh->lock, NULL, MUTEX_DEFAULT, NULL);
@@ -153,7 +153,7 @@ spa_read_history_init(spa_t *spa)
 	ssh->size = 0;
 	ssh->private = NULL;
 
-	(void) snprintf(name, KSTAT_STRLEN, "zfs/%s", spa_name(spa));
+	name = kmem_asprintf("zfs/%s", spa_name(spa));
 
 	ksp = kstat_create(name, 0, "reads", "misc",
 	    KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL);
@@ -168,6 +168,7 @@ spa_read_history_init(spa_t *spa)
 		    spa_read_history_data, spa_read_history_addr);
 		kstat_install(ksp);
 	}
+	strfree(name);
 }
 
 static void
@@ -365,7 +366,7 @@ static void
 spa_txg_history_init(spa_t *spa)
 {
 	spa_stats_history_t *ssh = &spa->spa_stats.txg_history;
-	char name[KSTAT_STRLEN];
+	char *name;
 	kstat_t *ksp;
 
 	mutex_init(&ssh->lock, NULL, MUTEX_DEFAULT, NULL);
@@ -376,7 +377,7 @@ spa_txg_history_init(spa_t *spa)
 	ssh->size = 0;
 	ssh->private = NULL;
 
-	(void) snprintf(name, KSTAT_STRLEN, "zfs/%s", spa_name(spa));
+	name = kmem_asprintf("zfs/%s", spa_name(spa));
 
 	ksp = kstat_create(name, 0, "txgs", "misc",
 	    KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL);
@@ -391,6 +392,7 @@ spa_txg_history_init(spa_t *spa)
 		    spa_txg_history_data, spa_txg_history_addr);
 		kstat_install(ksp);
 	}
+	strfree(name);
 }
 
 static void
@@ -598,7 +600,7 @@ static void
 spa_tx_assign_init(spa_t *spa)
 {
 	spa_stats_history_t *ssh = &spa->spa_stats.tx_assign_histogram;
-	char name[KSTAT_STRLEN];
+	char *name;
 	kstat_named_t *ks;
 	kstat_t *ksp;
 	int i;
@@ -609,7 +611,7 @@ spa_tx_assign_init(spa_t *spa)
 	ssh->size = ssh->count * sizeof (kstat_named_t);
 	ssh->private = kmem_alloc(ssh->size, KM_SLEEP);
 
-	(void) snprintf(name, KSTAT_STRLEN, "zfs/%s", spa_name(spa));
+	name = kmem_asprintf("zfs/%s", spa_name(spa));
 
 	for (i = 0; i < ssh->count; i++) {
 		ks = &((kstat_named_t *)ssh->private)[i];
@@ -632,6 +634,7 @@ spa_tx_assign_init(spa_t *spa)
 		ksp->ks_update = spa_tx_assign_update;
 		kstat_install(ksp);
 	}
+	strfree(name);
 }
 
 static void
@@ -678,12 +681,12 @@ static void
 spa_io_history_init(spa_t *spa)
 {
 	spa_stats_history_t *ssh = &spa->spa_stats.io_history;
-	char name[KSTAT_STRLEN];
+	char *name;
 	kstat_t *ksp;
 
 	mutex_init(&ssh->lock, NULL, MUTEX_DEFAULT, NULL);
 
-	(void) snprintf(name, KSTAT_STRLEN, "zfs/%s", spa_name(spa));
+	name = kmem_asprintf("zfs/%s", spa_name(spa));
 
 	ksp = kstat_create(name, 0, "io", "disk", KSTAT_TYPE_IO, 1, 0);
 	ssh->kstat = ksp;
@@ -694,6 +697,7 @@ spa_io_history_init(spa_t *spa)
 		ksp->ks_update = spa_io_history_update;
 		kstat_install(ksp);
 	}
+	strfree(name);
 }
 
 static void
@@ -806,7 +810,7 @@ static void
 spa_mmp_history_init(spa_t *spa)
 {
 	spa_stats_history_t *ssh = &spa->spa_stats.mmp_history;
-	char name[KSTAT_STRLEN];
+	char *name;
 	kstat_t *ksp;
 
 	mutex_init(&ssh->lock, NULL, MUTEX_DEFAULT, NULL);
@@ -817,7 +821,7 @@ spa_mmp_history_init(spa_t *spa)
 	ssh->size = 0;
 	ssh->private = NULL;
 
-	(void) snprintf(name, KSTAT_STRLEN, "zfs/%s", spa_name(spa));
+	name = kmem_asprintf("zfs/%s", spa_name(spa));
 
 	ksp = kstat_create(name, 0, "multihost", "misc",
 	    KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL);
@@ -832,6 +836,7 @@ spa_mmp_history_init(spa_t *spa)
 		    spa_mmp_history_data, spa_mmp_history_addr);
 		kstat_install(ksp);
 	}
+	strfree(name);
 }
 
 static void