Add feature check for 'zpool resilver' command

The 'zpool resilver' command requires that the resilver_defer
feature is active on the pool. Unfortunately, the check for
this was left out of the original patch. This commit simply
corrects this so that the command properly returns an error
in this case.

Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes openzfs#8700

include/libzfs.h

@@ -146,6 +146,7 @@ typedef enum zfs_error {
 	EZFS_TRIMMING,		/* currently trimming */
 	EZFS_NO_TRIM,		/* no active trim */
 	EZFS_TRIM_NOTSUP,	/* device does not support trim */
+	EZFS_NO_RESILVER_DEFER,	/* pool doesn't support resilver_defer */
 	EZFS_UNKNOWN
 } zfs_error_t;
 

lib/libzfs/libzfs_pool.c

@@ -2353,6 +2353,10 @@ zpool_scan(zpool_handle_t *zhp, pool_scan_func_t func, pool_scrub_cmd_t cmd)
 			(void) snprintf(msg, sizeof (msg), dgettext(TEXT_DOMAIN,
 			    "cannot scrub %s"), zc.zc_name);
 		}
+	} else if (func == POOL_SCAN_RESILVER) {
+		assert(cmd == POOL_SCRUB_NORMAL);
+		(void) snprintf(msg, sizeof (msg), dgettext(TEXT_DOMAIN,
+		    "cannot restart resilver on %s"), zc.zc_name);
 	} else if (func == POOL_SCAN_NONE) {
 		(void) snprintf(msg, sizeof (msg),
 		    dgettext(TEXT_DOMAIN, "cannot cancel scrubbing %s"),
@@ -2380,6 +2384,8 @@ zpool_scan(zpool_handle_t *zhp, pool_scan_func_t func, pool_scrub_cmd_t cmd)
 		}
 	} else if (err == ENOENT) {
 		return (zfs_error(hdl, EZFS_NO_SCRUB, msg));
+	} else if (err == ENOTSUP && func == POOL_SCAN_RESILVER) {
+		return (zfs_error(hdl, EZFS_NO_RESILVER_DEFER, msg));
 	} else {
 		return (zpool_standard_error(hdl, err, msg));
 	}

lib/libzfs/libzfs_util.c

@@ -312,6 +312,9 @@ libzfs_error_description(libzfs_handle_t *hdl)
 	case EZFS_TRIM_NOTSUP:
 		return (dgettext(TEXT_DOMAIN, "trim operations are not "
 		    "supported by this device"));
+	case EZFS_NO_RESILVER_DEFER:
+		return (dgettext(TEXT_DOMAIN, "this action requires the "
+		    "resilver_defer feature"));
 	case EZFS_UNKNOWN:
 		return (dgettext(TEXT_DOMAIN, "unknown error"));
 	default:

man/man8/zpool.8

@@ -2216,7 +2216,9 @@ again.
 .Xc
 Starts a resilver. If an existing resilver is already running it will be
 restarted from the beginning. Any drives that were scheduled for a deferred
-resilver will be added to the new one.
+resilver will be added to the new one. This requires the
+.Sy resilver_defer
+feature.
 .It Xo
 .Nm
 .Cm trim

module/zfs/spa.c

@@ -7264,6 +7264,10 @@ spa_scan(spa_t *spa, pool_scan_func_t func)
 	if (func >= POOL_SCAN_FUNCS || func == POOL_SCAN_NONE)
 		return (SET_ERROR(ENOTSUP));
 
+	if (func == POOL_SCAN_RESILVER &&
+	    !spa_feature_is_enabled(spa, SPA_FEATURE_RESILVER_DEFER))
+		return (SET_ERROR(ENOTSUP));
+
 	/*
 	 * If a resilver was requested, but there is no DTL on a
 	 * writeable leaf device, we have nothing to do.

tests/zfs-tests/tests/functional/cli_root/zpool_resilver/zpool_resilver_bad_args.ksh

@@ -35,6 +35,8 @@
 # 1. Create an array containing bad 'zpool reilver' parameters.
 # 2. For each element, execute the sub-command.
 # 3. Verify it returns an error.
+# 4. Confirm the sub-command returns an error if the resilver_defer
+#    feature isn't active.
 #
 
 verify_runnable "global"
@@ -45,6 +47,13 @@ set -A args "" "-?" "blah blah" "-%" "--?" "-*" "-=" \
     "-A" "-B" "-C" "-D" "-E" "-F" "-G" "-H" "-I" "-J" "-K" "-L" \
     "-M" "-N" "-O" "-P" "-Q" "-R" "-S" "-T" "-U" "-V" "-W" "-X" "-W" "-Z"
 
+function cleanup
+{
+	log_must destroy_pool $TESTPOOL2
+	log_must rm -f $TEST_BASE_DIR/zpool_resilver.dat
+}
+
+log_onexit cleanup
 
 log_assert "Execute 'zpool resilver' using invalid parameters."
 
@@ -55,4 +64,8 @@ while [[ $i -lt ${#args[*]} ]]; do
 	((i = i + 1))
 done
 
+log_must mkfile $MINVDEVSIZE $TEST_BASE_DIR/zpool_resilver.dat
+log_must zpool create -d $TESTPOOL2 $TEST_BASE_DIR/zpool_resilver.dat
+log_mustnot zpool resilver $TESTPOOL2
+
 log_pass "Badly formed 'zpool resilver' parameters fail as expected."