Inject zinject(8) a percentage amount of dev errs

In the original form of device error injection, it was an all or nothing
situation.  To help simulate intermittent error conditions, you can now
specify a real number percentage value. This is also very useful for our
ZFS fault diagnosis testing and for injecting intermittent errors during
load testing.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Don Brady <[email protected]>
Closes #6227 

1 files changed, 38 insertions, 10 deletions

diff --git a/cmd/zinject/zinject.c b/cmd/zinject/zinject.c
index 604554e71..ccd3534d0 100644
--- a/cmd/zinject/zinject.c
+++ b/cmd/zinject/zinject.c
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
+ * Copyright (c) 2017, Intel Corporation.
  */
 
 /*
@@ -124,7 +125,7 @@
  * cache.
  *
  * The '-f' flag controls the frequency of errors injected, expressed as a
- * integer percentage between 1 and 100.  The default is 100.
+ * real number percentage between 0.0001 and 100.  The default is 100.
  *
  * The this form is responsible for actually injecting the handler into the
  * framework.  It takes the arguments described above, translates them to the
@@ -230,11 +231,13 @@ usage(void)
 	    "\t\tspa_vdev_exit() will trigger a panic.\n"
 	    "\n"
 	    "\tzinject -d device [-e errno] [-L <nvlist|uber|pad1|pad2>] [-F]\n"
-	    "\t    [-T <read|write|free|claim|all> pool\n"
+	    "\t    [-T <read|write|free|claim|all>] [-f frequency] pool\n"
 	    "\t\tInject a fault into a particular device or the device's\n"
 	    "\t\tlabel.  Label injection can either be 'nvlist', 'uber',\n "
 	    "\t\t'pad1', or 'pad2'.\n"
 	    "\t\t'errno' can be 'nxio' (the default), 'io', or 'dtl'.\n"
+	    "\t\t'frequency' is a value between 0.0001 and 100.0 that limits\n"
+	    "\t\tdevice error injection to a percentage of the IOs.\n"
 	    "\n"
 	    "\tzinject -d device -A <degrade|fault> -D <delay secs> pool\n"
 	    "\t\tPerform a specific action on a particular device.\n"
@@ -305,7 +308,7 @@ usage(void)
 	    "\t\t-u\tUnload the associated pool.  Can be specified with only\n"
 	    "\t\t\ta pool object.\n"
 	    "\t\t-f\tOnly inject errors a fraction of the time.  Expressed as\n"
-	    "\t\t\ta percentage between 1 and 100.\n"
+	    "\t\t\ta percentage between 0.0001 and 100.\n"
 	    "\n"
 	    "\t-t data\t\tInject an error into the plain file contents of a\n"
 	    "\t\t\tfile.  The object must be specified as a complete path\n"
@@ -645,6 +648,27 @@ parse_delay(char *str, uint64_t *delay, uint64_t *nlanes)
 	return (0);
 }
 
+static int
+parse_frequency(const char *str, uint32_t *percent)
+{
+	double val;
+	char *post;
+
+	val = strtod(str, &post);
+	if (post == NULL || *post != '\0')
+		return (EINVAL);
+
+	/* valid range is [0.0001, 100.0] */
+	val /= 100.0f;
+	if (val < 0.000001f || val > 1.0f)
+		return (ERANGE);
+
+	/* convert to an integer for use by kernel */
+	*percent = ((uint32_t)(val * ZI_PERCENTAGE_MAX));
+
+	return (0);
+}
+
 int
 main(int argc, char **argv)
 {
@@ -760,10 +784,12 @@ main(int argc, char **argv)
 			}
 			break;
 		case 'f':
-			record.zi_freq = atoi(optarg);
-			if (record.zi_freq < 1 || record.zi_freq > 100) {
-				(void) fprintf(stderr, "frequency range must "
-				    "be in the range (0, 100]\n");
+			ret = parse_frequency(optarg, &record.zi_freq);
+			if (ret != 0) {
+				(void) fprintf(stderr, "%sfrequency value must "
+				    "be in the range [0.0001, 100.0]\n",
+				    ret == EINVAL ? "invalid value: " :
+				    ret == ERANGE ? "out of range: " : "");
 				libzfs_fini(g_zfs);
 				return (1);
 			}
@@ -898,7 +924,8 @@ main(int argc, char **argv)
 		 * '-c' is invalid with any other options.
 		 */
 		if (raw != NULL || range != NULL || type != TYPE_INVAL ||
-		    level != 0 || record.zi_cmd != ZINJECT_UNINITIALIZED) {
+		    level != 0 || record.zi_cmd != ZINJECT_UNINITIALIZED ||
+		    record.zi_freq > 0) {
 			(void) fprintf(stderr, "cancel (-c) incompatible with "
 			    "any other options\n");
 			usage();
@@ -972,7 +999,8 @@ main(int argc, char **argv)
 
 	} else if (raw != NULL) {
 		if (range != NULL || type != TYPE_INVAL || level != 0 ||
-		    record.zi_cmd != ZINJECT_UNINITIALIZED) {
+		    record.zi_cmd != ZINJECT_UNINITIALIZED ||
+		    record.zi_freq > 0) {
 			(void) fprintf(stderr, "raw (-b) format with "
 			    "any other options\n");
 			usage();
@@ -1007,7 +1035,7 @@ main(int argc, char **argv)
 			error = EIO;
 	} else if (record.zi_cmd == ZINJECT_PANIC) {
 		if (raw != NULL || range != NULL || type != TYPE_INVAL ||
-		    level != 0 || device != NULL) {
+		    level != 0 || device != NULL || record.zi_freq > 0) {
 			(void) fprintf(stderr, "panic (-p) incompatible with "
 			    "other options\n");
 			usage();