svn commit: r356176 - in head: lib/geom/nop sys/geom/nop

[Mariusz Zaborski]

Author: oshogbo
Date: Sun Dec 29 15:47:37 2019
New Revision: 356176
URL: https://svnweb.freebsd.org/changeset/base/356176

Log:
  gnop: change the "count until fail" option
  
  Change the "count_until_fail" option of gnop, now it enables the failing
  rating instead of setting them to 100%.
  
  The original patch introduced the new flag, which sets the fail/rate to 100%
  after N requests. In some cases, we don't want to have 100% of failure
  probabilities. We want to start failing at some point.
  For example, on the early stage, we may like to allow some read/writes requests
  before having some requests delayed - when we try to mount the partition,
  or when we are trying to import the pool.
  Another case may be to check how scrub in ZFS will behave on different stages.
  
  This allows us to cover more cases.
  The previous behavior still may be configured.
  
  Reviewed by:	kib
  Differential Revision:	https://reviews.freebsd.org/D22632

Modified:
  head/lib/geom/nop/gnop.8
  head/sys/geom/nop/g_nop.c

Modified: head/lib/geom/nop/gnop.8
==============================================================================
--- head/lib/geom/nop/gnop.8	Sun Dec 29 15:46:59 2019	(r356175)
+++ head/lib/geom/nop/gnop.8	Sun Dec 29 15:47:37 2019	(r356176)
@@ -123,8 +123,8 @@ See
 Additional options:
 .Bl -tag -width "-c count_until_fail"
 .It Fl c Ar count_until_fail
-Specifies the number of I/O requests to allow before setting the read and write
-failure probabilities to 100%.
+Specifies the number of I/O requests to allow before setting the read, write and
+delay failure probabilities.
 .It Fl d Ar delaymsec
 Specifies the delay of the requests in milliseconds.
 Note that requests will be delayed before they are sent to the backing device.

Modified: head/sys/geom/nop/g_nop.c
==============================================================================
--- head/sys/geom/nop/g_nop.c	Sun Dec 29 15:46:59 2019	(r356175)
+++ head/sys/geom/nop/g_nop.c	Sun Dec 29 15:47:37 2019	(r356176)
@@ -204,31 +204,35 @@ g_nop_start(struct bio *bp)
 	struct bio *cbp;
 	u_int failprob, delayprob, delaytime;
 
-	failprob = delayprob = 0;
+	failprob = delayprob = delaytime = 0;
 
 	gp = bp->bio_to->geom;
 	sc = gp->softc;
 
 	G_NOP_LOGREQ(bp, "Request received.");
 	mtx_lock(&sc->sc_lock);
-	if (sc->sc_count_until_fail != 0 && --sc->sc_count_until_fail == 0) {
-		sc->sc_rfailprob = 100;
-		sc->sc_wfailprob = 100;
-	}
 	switch (bp->bio_cmd) {
 	case BIO_READ:
 		sc->sc_reads++;
 		sc->sc_readbytes += bp->bio_length;
-		failprob = sc->sc_rfailprob;
-		delayprob = sc->sc_rdelayprob;
-		delaytime = sc->sc_delaymsec;
+		if (sc->sc_count_until_fail != 0) {
+			sc->sc_count_until_fail -= 1;
+		} else {
+			failprob = sc->sc_rfailprob;
+			delayprob = sc->sc_rdelayprob;
+			delaytime = sc->sc_delaymsec;
+		}
 		break;
 	case BIO_WRITE:
 		sc->sc_writes++;
 		sc->sc_wrotebytes += bp->bio_length;
-		failprob = sc->sc_wfailprob;
-		delayprob = sc->sc_wdelayprob;
-		delaytime = sc->sc_delaymsec;
+		if (sc->sc_count_until_fail != 0) {
+			sc->sc_count_until_fail -= 1;
+		} else {
+			failprob = sc->sc_wfailprob;
+			delayprob = sc->sc_wdelayprob;
+			delaytime = sc->sc_delaymsec;
+		}
 		break;
 	case BIO_DELETE:
 		sc->sc_deletes++;
@@ -262,6 +266,7 @@ g_nop_start(struct bio *bp)
 		break;
 	}
 	mtx_unlock(&sc->sc_lock);
+
 	if (failprob > 0) {
 		u_int rval;