Allow to control failfast

Linux defaults to setting "failfast" on BIOs, so that the OS will not
retry IOs that fail, and instead report the error to ZFS.

In some cases, such as errors reported by the HBA driver, not
the device itself, we would wish to retry rather than generating
vdev errors in ZFS. This new property allows that.

This introduces a per vdev option to disable the failfast option.
This also introduces a global module parameter to define the failfast
mask value.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Mariusz Zaborski <mariusz.zaborski@klarasystems.com>
Sponsored-by: Seagate Technology LLC
Submitted-by: Klara, Inc.
Closes #14056

module/os/linux/zfs/vdev_disk.c

@@ -74,6 +74,12 @@ typedef struct dio_request {
 	struct bio		*dr_bio[0];	/* Attached bio's */
 } dio_request_t;
 
+/*
+ * BIO request failfast mask.
+ */
+
+static unsigned int zfs_vdev_failfast_mask = 1;
+
 static fmode_t
 vdev_bdev_mode(spa_mode_t spa_mode)
 {
@@ -659,8 +665,11 @@ __vdev_disk_physio(struct block_device *bdev, zio_t *zio,
 retry:
 	dr = vdev_disk_dio_alloc(bio_count);
 
-	if (zio && !(zio->io_flags & (ZIO_FLAG_IO_RETRY | ZIO_FLAG_TRYHARD)))
-		bio_set_flags_failfast(bdev, &flags);
+	if (zio && !(zio->io_flags & (ZIO_FLAG_IO_RETRY | ZIO_FLAG_TRYHARD)) &&
+	    zio->io_vd->vdev_failfast == B_TRUE) {
+		bio_set_flags_failfast(bdev, &flags, zfs_vdev_failfast_mask & 1,
+		    zfs_vdev_failfast_mask & 2, zfs_vdev_failfast_mask & 4);
+	}
 
 	dr->dr_zio = zio;
 
@@ -1045,3 +1054,6 @@ param_set_max_auto_ashift(const char *buf, zfs_kernel_param_t *kp)
 
 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, open_timeout_ms, UINT, ZMOD_RW,
 	"Timeout before determining that a device is missing");
+
+ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, failfast_mask, UINT, ZMOD_RW,
+	"Defines failfast mask: 1 - device, 2 - transport, 4 - driver");

module/zcommon/zpool_prop.c

@@ -420,6 +420,9 @@ vdev_prop_init(void)
 	    boolean_na_table, sfeatures);
 
 	/* default index properties */
+	zprop_register_index(VDEV_PROP_FAILFAST, "failfast", B_TRUE,
+	    PROP_DEFAULT, ZFS_TYPE_VDEV, "on | off", "FAILFAST", boolean_table,
+	    sfeatures);
 
 	/* hidden properties */
 	zprop_register_hidden(VDEV_PROP_NAME, "name", PROP_TYPE_STRING,

module/zfs/vdev.c

@@ -3563,6 +3563,26 @@ vdev_load(vdev_t *vd)
 		}
 	}
 
+	if (vd == vd->vdev_top && vd->vdev_top_zap != 0) {
+		spa_t *spa = vd->vdev_spa;
+		uint64_t failfast;
+
+		error = zap_lookup(spa->spa_meta_objset, vd->vdev_top_zap,
+		    vdev_prop_to_name(VDEV_PROP_FAILFAST), sizeof (failfast),
+		    1, &failfast);
+		if (error == 0) {
+			vd->vdev_failfast = failfast & 1;
+		} else if (error == ENOENT) {
+			vd->vdev_failfast = vdev_prop_default_numeric(
+			    VDEV_PROP_FAILFAST);
+		} else {
+			vdev_dbgmsg(vd,
+			    "vdev_load: zap_lookup(top_zap=%llu) "
+			    "failed [error=%d]",
+			    (u_longlong_t)vd->vdev_top_zap, error);
+		}
+	}
+
 	/*
 	 * Load any rebuild state from the top-level vdev zap.
 	 */
@@ -5709,6 +5729,13 @@ vdev_prop_set(vdev_t *vd, nvlist_t *innvl, nvlist_t *outnvl)
 			else
 				error = spa_vdev_alloc(spa, vdev_guid);
 			break;
+		case VDEV_PROP_FAILFAST:
+			if (nvpair_value_uint64(elem, &intval) != 0) {
+				error = EINVAL;
+				break;
+			}
+			vd->vdev_failfast = intval & 1;
+			break;
 		default:
 			/* Most processing is done in vdev_props_set_sync */
 			break;
@@ -6019,6 +6046,25 @@ vdev_prop_get(vdev_t *vd, nvlist_t *innvl, nvlist_t *outnvl)
 					intval = ZPROP_BOOLEAN_NA;
 				}
 
+				vdev_prop_add_list(outnvl, propname, strval,
+				    intval, src);
+				break;
+			case VDEV_PROP_FAILFAST:
+				src = ZPROP_SRC_LOCAL;
+				strval = NULL;
+
+				err = zap_lookup(mos, objid, nvpair_name(elem),
+				    sizeof (uint64_t), 1, &intval);
+				if (err == ENOENT) {
+					intval = vdev_prop_default_numeric(
+					    prop);
+					err = 0;
+				} else if (err) {
+					break;
+				}
+				if (intval == vdev_prop_default_numeric(prop))
+					src = ZPROP_SRC_DEFAULT;
+
 				vdev_prop_add_list(outnvl, propname, strval,
 				    intval, src);
 				break;