Date: Wed, 5 Jan 2011 00:19:40 +0000 (UTC) From: Warner Losh <imp@FreeBSD.org> To: src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: svn commit: r216984 - projects/graid/head/sys/geom/raid Message-ID: <201101050019.p050Je5J059533@svn.freebsd.org>
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Author: imp Date: Wed Jan 5 00:19:40 2011 New Revision: 216984 URL: http://svn.freebsd.org/changeset/base/216984 Log: First pass at error recovery: if the first disk that we get errors on has a problem, try from the second one. Note info about possible bad sector remap attempt through write, and some ideas on when to eject the subdisk from the disk. Modified: projects/graid/head/sys/geom/raid/g_raid.h projects/graid/head/sys/geom/raid/tr_raid1.c Modified: projects/graid/head/sys/geom/raid/g_raid.h ============================================================================== --- projects/graid/head/sys/geom/raid/g_raid.h Tue Jan 4 23:00:54 2011 (r216983) +++ projects/graid/head/sys/geom/raid/g_raid.h Wed Jan 5 00:19:40 2011 (r216984) @@ -137,6 +137,7 @@ struct g_raid_subdisk { off_t sd_size; /* Size on the disk. */ u_int sd_pos; /* Position in volume. */ u_int sd_state; /* Subdisk state. */ + int sd_read_errs; /* Count of the read errors */ LIST_ENTRY(g_raid_subdisk) sd_next; /* Next subdisk on disk. */ }; Modified: projects/graid/head/sys/geom/raid/tr_raid1.c ============================================================================== --- projects/graid/head/sys/geom/raid/tr_raid1.c Tue Jan 4 23:00:54 2011 (r216983) +++ projects/graid/head/sys/geom/raid/tr_raid1.c Wed Jan 5 00:19:40 2011 (r216984) @@ -164,24 +164,34 @@ g_raid_tr_stop_raid1(struct g_raid_tr_ob return (0); } +/* + * Select the disk to do the reads to. For now, we just pick the + * first one in the list that's active always. This ensures we favor + * one disk on boot, and have more deterministic recovery from the + * weird edge cases of power failure. In the future, we can imagine + * policies that go for the least loaded disk to improve performance, + * or we need to limit reads to a disk during some kind of error + * recovery with that disk. + */ +static struct g_raid_subdisk * +g_raid_tr_raid1_select_read_disk(struct g_raid_volume *vol) +{ + int i; + + for (i = 0; i < vol->v_disks_count; i++) + if (vol->v_subdisks[i].sd_state == G_RAID_SUBDISK_S_ACTIVE) + return (&vol->v_subdisks[i]); + return (NULL); +} + static void g_raid_tr_iostart_raid1_read(struct g_raid_tr_object *tr, struct bio *bp) { - struct g_raid_softc *sc; - struct g_raid_volume *vol; struct g_raid_subdisk *sd; struct bio *cbp; - int i; - vol = tr->tro_volume; - sc = vol->v_softc; - sd = NULL; - for (i = 0; i < vol->v_disks_count; i++) { - if (vol->v_subdisks[i].sd_state != G_RAID_SUBDISK_S_ACTIVE) - continue; - sd = &vol->v_subdisks[i]; - } - KASSERT(sd != NULL, ("No active disks in volume %s.", vol->v_name)); + sd = g_raid_tr_raid1_select_read_disk(tr->tro_volume); + KASSERT(sd != NULL, ("No active disks in volume %s.", tr->tro_volume->v_name)); cbp = g_clone_bio(bp); if (cbp == NULL) { @@ -283,6 +293,53 @@ g_raid_tr_iodone_raid1(struct g_raid_tr_ pbp = bp->bio_parent; pbp->bio_inbed++; + if ((pbp->bio_flags & BIO_ERROR) && pbp->bio_cmd == BIO_READ && + pbp->bio_children == 1) { + struct bio *cbp; + struct g_raid_subdisk *nsd; + struct g_raid_volume *vol; + int i; + + /* + * Retry the error on the other disk drive, if available, + * before erroring out the read. Do we need to mark the + * 'sd' disk as degraded somehow? + */ + vol = tr->tro_volume; + sd->sd_read_errs++; + /* + * XXX Check threshold of sd_read_errs here to declare + * this subdisk bad? + */ + for (nsd = NULL, i = 0; i < vol->v_disks_count; i++) { + nsd = &vol->v_subdisks[i]; + if (sd == nsd) + continue; + if (nsd->sd_state != G_RAID_SUBDISK_S_ACTIVE) + continue; + cbp = g_clone_bio(pbp); + if (cbp == NULL) + break; + g_raid_subdisk_iostart(nsd, cbp); + return; + } + /* + * something happened, so we can't retry. Return the + * original error by falling through. + */ + } + /* + * If it was a read, and bio_children is 2, then we just + * recovered the data from the second drive. We should try to + * write that data to the first drive if sector remapping is + * enabled. A write should put the data in a new place on the + * disk, remapping the bad sector. Do we need to do that by + * queueing a request to the main worker thread? It doesn't + * affect the return code of this current read, and can be + * done at our liesure. + * + * XXX TODO + */ if (pbp->bio_children == pbp->bio_inbed) { pbp->bio_completed = pbp->bio_length; g_raid_iodone(pbp, bp->bio_error);
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