Implemented zpool scrub pause/resume

Currently, there is no way to pause a scrub. Pausing may
be useful when the pool is busy with other I/O to preserve
bandwidth.

This patch adds the ability to pause and resume scrubbing.
This is achieved by maintaining a persistent on-disk scrub state.
While the state is 'paused' we do not scrub any more blocks.
We do however perform regular scan housekeeping such as
freeing async destroyed and deadlist blocks while paused.

Reviewed by: Matthew Ahrens <[email protected]>
Reviewed by: Thomas Caputi <[email protected]>
Reviewed-by: Serapheim Dimitropoulos <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Alek Pinchuk <[email protected]>
Closes #6167

1 files changed, 26 insertions, 15 deletions

diff --git a/tests/zfs-tests/include/libtest.shlib b/tests/zfs-tests/include/libtest.shlib
index 5d8500ddf..034b36691 100644
--- a/tests/zfs-tests/include/libtest.shlib
+++ b/tests/zfs-tests/include/libtest.shlib
@@ -1999,54 +1999,65 @@ function check_vdev_state # pool disk state{online,offline,unavail}
 #
 # Return 0 is contain, 1 otherwise
 #
-function check_pool_status # pool token keyword
+function check_pool_status # pool token keyword <verbose>
 {
 	typeset pool=$1
 	typeset token=$2
 	typeset keyword=$3
+	typeset verbose=${4:-false}
 
-	zpool status -v "$pool" 2>/dev/null | nawk -v token="$token:" '
-		($1==token) {print $0}' \
-	| grep -i "$keyword" > /dev/null 2>&1
+	scan=$(zpool status -v "$pool" 2>/dev/null | nawk -v token="$token:" '
+		($1==token) {print $0}')
+	if [[ $verbose == true ]]; then
+		log_note $scan
+	fi
+	echo $scan | grep -i "$keyword" > /dev/null 2>&1
 
 	return $?
 }
 
 #
-# These 5 following functions are instance of check_pool_status()
+# These 6 following functions are instance of check_pool_status()
 #	is_pool_resilvering - to check if the pool is resilver in progress
 #	is_pool_resilvered - to check if the pool is resilver completed
 #	is_pool_scrubbing - to check if the pool is scrub in progress
 #	is_pool_scrubbed - to check if the pool is scrub completed
 #	is_pool_scrub_stopped - to check if the pool is scrub stopped
+#	is_pool_scrub_paused - to check if the pool has scrub paused
 #
-function is_pool_resilvering #pool
+function is_pool_resilvering #pool <verbose>
+{
+	check_pool_status "$1" "scan" "resilver in progress since " $2
+	return $?
+}
+
+function is_pool_resilvered #pool <verbose>
 {
-	check_pool_status "$1" "scan" "resilver in progress since "
+	check_pool_status "$1" "scan" "resilvered " $2
 	return $?
 }
 
-function is_pool_resilvered #pool
+function is_pool_scrubbing #pool <verbose>
 {
-	check_pool_status "$1" "scan" "resilvered "
+	check_pool_status "$1" "scan" "scrub in progress since " $2
 	return $?
 }
 
-function is_pool_scrubbing #pool
+function is_pool_scrubbed #pool <verbose>
 {
-	check_pool_status "$1" "scan" "scrub in progress since "
+	check_pool_status "$1" "scan" "scrub repaired" $2
 	return $?
 }
 
-function is_pool_scrubbed #pool
+function is_pool_scrub_stopped #pool <verbose>
 {
-	check_pool_status "$1" "scan" "scrub repaired"
+	check_pool_status "$1" "scan" "scrub canceled" $2
 	return $?
 }
 
-function is_pool_scrub_stopped #pool
+function is_pool_scrub_paused #pool <verbose>
 {
-	check_pool_status "$1" "scan" "scrub canceled"
+	check_pool_status "$1" "scan" "scrub paused since " $2
 	return $?
 }