From d69762e98456b71167865db9e33e732a28dd36ab Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 6 Jan 2006 00:20:18 -0800 Subject: [PATCH] [PATCH] md: improve handing of read errors with raid6 This is a simple port of match functionality across from raid5. If we get a read error, we don't kick the drive straight away, but try to over-write with good data first. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/raid6main.c | 70 +++++++++++++++++++++++++++++++++++++++--- 1 file changed, 66 insertions(+), 4 deletions(-) diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c index 52e8796bb8..7a51553d8b 100644 --- a/drivers/md/raid6main.c +++ b/drivers/md/raid6main.c @@ -367,8 +367,8 @@ static void shrink_stripes(raid6_conf_t *conf) conf->slab_cache = NULL; } -static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done, - int error) +static int raid6_end_read_request(struct bio * bi, unsigned int bytes_done, + int error) { struct stripe_head *sh = bi->bi_private; raid6_conf_t *conf = sh->raid_conf; @@ -420,9 +420,35 @@ static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done, #else set_bit(R5_UPTODATE, &sh->dev[i].flags); #endif + if (test_bit(R5_ReadError, &sh->dev[i].flags)) { + printk(KERN_INFO "raid6: read error corrected!!\n"); + clear_bit(R5_ReadError, &sh->dev[i].flags); + clear_bit(R5_ReWrite, &sh->dev[i].flags); + } + if (atomic_read(&conf->disks[i].rdev->read_errors)) + atomic_set(&conf->disks[i].rdev->read_errors, 0); } else { - md_error(conf->mddev, conf->disks[i].rdev); + int retry = 0; clear_bit(R5_UPTODATE, &sh->dev[i].flags); + atomic_inc(&conf->disks[i].rdev->read_errors); + if (conf->mddev->degraded) + printk(KERN_WARNING "raid6: read error not correctable.\n"); + else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) + /* Oh, no!!! */ + printk(KERN_WARNING "raid6: read error NOT corrected!!\n"); + else if (atomic_read(&conf->disks[i].rdev->read_errors) + > conf->max_nr_stripes) + printk(KERN_WARNING + "raid6: Too many read errors, failing device.\n"); + else + retry = 1; + if (retry) + set_bit(R5_ReadError, &sh->dev[i].flags); + else { + clear_bit(R5_ReadError, &sh->dev[i].flags); + clear_bit(R5_ReWrite, &sh->dev[i].flags); + md_error(conf->mddev, conf->disks[i].rdev); + } } rdev_dec_pending(conf->disks[i].rdev, conf->mddev); #if 0 @@ -1079,6 +1105,12 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page) if (dev->written) written++; rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */ if (!rdev || !test_bit(In_sync, &rdev->flags)) { + /* The ReadError flag will just be confusing now */ + clear_bit(R5_ReadError, &dev->flags); + clear_bit(R5_ReWrite, &dev->flags); + } + if (!rdev || !test_bit(In_sync, &rdev->flags) + || test_bit(R5_ReadError, &dev->flags)) { if ( failed < 2 ) failed_num[failed] = i; failed++; @@ -1095,6 +1127,14 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page) if (failed > 2 && to_read+to_write+written) { for (i=disks; i--; ) { int bitmap_end = 0; + + if (test_bit(R5_ReadError, &sh->dev[i].flags)) { + mdk_rdev_t *rdev = conf->disks[i].rdev; + if (rdev && test_bit(In_sync, &rdev->flags)) + /* multiple read failures in one stripe */ + md_error(conf->mddev, rdev); + } + spin_lock_irq(&conf->device_lock); /* fail all writes first */ bi = sh->dev[i].towrite; @@ -1130,7 +1170,8 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page) } /* fail any reads if this device is non-operational */ - if (!test_bit(R5_Insync, &sh->dev[i].flags)) { + if (!test_bit(R5_Insync, &sh->dev[i].flags) || + test_bit(R5_ReadError, &sh->dev[i].flags)) { bi = sh->dev[i].toread; sh->dev[i].toread = NULL; if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) @@ -1457,6 +1498,27 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page) clear_bit(STRIPE_SYNCING, &sh->state); } + /* If the failed drives are just a ReadError, then we might need + * to progress the repair/check process + */ + if (failed <= 2 && ! conf->mddev->ro) + for (i=0; idev[failed_num[i]]; + if (test_bit(R5_ReadError, &dev->flags) + && !test_bit(R5_LOCKED, &dev->flags) + && test_bit(R5_UPTODATE, &dev->flags) + ) { + if (!test_bit(R5_ReWrite, &dev->flags)) { + set_bit(R5_Wantwrite, &dev->flags); + set_bit(R5_ReWrite, &dev->flags); + set_bit(R5_LOCKED, &dev->flags); + } else { + /* let's read it back */ + set_bit(R5_Wantread, &dev->flags); + set_bit(R5_LOCKED, &dev->flags); + } + } + } spin_unlock(&sh->lock); while ((bi=return_bi)) { -- 2.39.5