diff options
Diffstat (limited to 'drivers/md/raid1.c')
-rw-r--r-- | drivers/md/raid1.c | 962 |
1 files changed, 735 insertions, 227 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index f7431b6d8447..32323f0afd89 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -35,16 +35,13 @@ #include <linux/delay.h> #include <linux/blkdev.h> #include <linux/seq_file.h> +#include <linux/ratelimit.h> #include "md.h" #include "raid1.h" #include "bitmap.h" #define DEBUG 0 -#if DEBUG -#define PRINTK(x...) printk(x) -#else -#define PRINTK(x...) -#endif +#define PRINTK(x...) do { if (DEBUG) printk(x); } while (0) /* * Number of guaranteed r1bios in case of extreme VM load: @@ -166,7 +163,7 @@ static void put_all_bios(conf_t *conf, r1bio_t *r1_bio) for (i = 0; i < conf->raid_disks; i++) { struct bio **bio = r1_bio->bios + i; - if (*bio && *bio != IO_BLOCKED) + if (!BIO_SPECIAL(*bio)) bio_put(*bio); *bio = NULL; } @@ -176,12 +173,6 @@ static void free_r1bio(r1bio_t *r1_bio) { conf_t *conf = r1_bio->mddev->private; - /* - * Wake up any possible resync thread that waits for the device - * to go idle. - */ - allow_barrier(conf); - put_all_bios(conf, r1_bio); mempool_free(r1_bio, conf->r1bio_pool); } @@ -222,6 +213,33 @@ static void reschedule_retry(r1bio_t *r1_bio) * operation and are ready to return a success/failure code to the buffer * cache layer. */ +static void call_bio_endio(r1bio_t *r1_bio) +{ + struct bio *bio = r1_bio->master_bio; + int done; + conf_t *conf = r1_bio->mddev->private; + + if (bio->bi_phys_segments) { + unsigned long flags; + spin_lock_irqsave(&conf->device_lock, flags); + bio->bi_phys_segments--; + done = (bio->bi_phys_segments == 0); + spin_unlock_irqrestore(&conf->device_lock, flags); + } else + done = 1; + + if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) + clear_bit(BIO_UPTODATE, &bio->bi_flags); + if (done) { + bio_endio(bio, 0); + /* + * Wake up any possible resync thread that waits for the device + * to go idle. + */ + allow_barrier(conf); + } +} + static void raid_end_bio_io(r1bio_t *r1_bio) { struct bio *bio = r1_bio->master_bio; @@ -234,8 +252,7 @@ static void raid_end_bio_io(r1bio_t *r1_bio) (unsigned long long) bio->bi_sector + (bio->bi_size >> 9) - 1); - bio_endio(bio, - test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO); + call_bio_endio(r1_bio); } free_r1bio(r1_bio); } @@ -287,36 +304,52 @@ static void raid1_end_read_request(struct bio *bio, int error) * oops, read error: */ char b[BDEVNAME_SIZE]; - if (printk_ratelimit()) - printk(KERN_ERR "md/raid1:%s: %s: rescheduling sector %llu\n", - mdname(conf->mddev), - bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector); + printk_ratelimited( + KERN_ERR "md/raid1:%s: %s: " + "rescheduling sector %llu\n", + mdname(conf->mddev), + bdevname(conf->mirrors[mirror].rdev->bdev, + b), + (unsigned long long)r1_bio->sector); + set_bit(R1BIO_ReadError, &r1_bio->state); reschedule_retry(r1_bio); } rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev); } +static void close_write(r1bio_t *r1_bio) +{ + /* it really is the end of this request */ + if (test_bit(R1BIO_BehindIO, &r1_bio->state)) { + /* free extra copy of the data pages */ + int i = r1_bio->behind_page_count; + while (i--) + safe_put_page(r1_bio->behind_bvecs[i].bv_page); + kfree(r1_bio->behind_bvecs); + r1_bio->behind_bvecs = NULL; + } + /* clear the bitmap if all writes complete successfully */ + bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector, + r1_bio->sectors, + !test_bit(R1BIO_Degraded, &r1_bio->state), + test_bit(R1BIO_BehindIO, &r1_bio->state)); + md_write_end(r1_bio->mddev); +} + static void r1_bio_write_done(r1bio_t *r1_bio) { - if (atomic_dec_and_test(&r1_bio->remaining)) - { - /* it really is the end of this request */ - if (test_bit(R1BIO_BehindIO, &r1_bio->state)) { - /* free extra copy of the data pages */ - int i = r1_bio->behind_page_count; - while (i--) - safe_put_page(r1_bio->behind_pages[i]); - kfree(r1_bio->behind_pages); - r1_bio->behind_pages = NULL; - } - /* clear the bitmap if all writes complete successfully */ - bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector, - r1_bio->sectors, - !test_bit(R1BIO_Degraded, &r1_bio->state), - test_bit(R1BIO_BehindIO, &r1_bio->state)); - md_write_end(r1_bio->mddev); - raid_end_bio_io(r1_bio); + if (!atomic_dec_and_test(&r1_bio->remaining)) + return; + + if (test_bit(R1BIO_WriteError, &r1_bio->state)) + reschedule_retry(r1_bio); + else { + close_write(r1_bio); + if (test_bit(R1BIO_MadeGood, &r1_bio->state)) + reschedule_retry(r1_bio); + else + raid_end_bio_io(r1_bio); } } @@ -336,13 +369,11 @@ static void raid1_end_write_request(struct bio *bio, int error) /* * 'one mirror IO has finished' event handler: */ - r1_bio->bios[mirror] = NULL; - to_put = bio; if (!uptodate) { - md_error(r1_bio->mddev, conf->mirrors[mirror].rdev); - /* an I/O failed, we can't clear the bitmap */ - set_bit(R1BIO_Degraded, &r1_bio->state); - } else + set_bit(WriteErrorSeen, + &conf->mirrors[mirror].rdev->flags); + set_bit(R1BIO_WriteError, &r1_bio->state); + } else { /* * Set R1BIO_Uptodate in our master bio, so that we * will return a good error code for to the higher @@ -353,8 +384,22 @@ static void raid1_end_write_request(struct bio *bio, int error) * to user-side. So if something waits for IO, then it * will wait for the 'master' bio. */ + sector_t first_bad; + int bad_sectors; + + r1_bio->bios[mirror] = NULL; + to_put = bio; set_bit(R1BIO_Uptodate, &r1_bio->state); + /* Maybe we can clear some bad blocks. */ + if (is_badblock(conf->mirrors[mirror].rdev, + r1_bio->sector, r1_bio->sectors, + &first_bad, &bad_sectors)) { + r1_bio->bios[mirror] = IO_MADE_GOOD; + set_bit(R1BIO_MadeGood, &r1_bio->state); + } + } + update_head_pos(mirror, r1_bio); if (behind) { @@ -377,11 +422,13 @@ static void raid1_end_write_request(struct bio *bio, int error) (unsigned long long) mbio->bi_sector, (unsigned long long) mbio->bi_sector + (mbio->bi_size >> 9) - 1); - bio_endio(mbio, 0); + call_bio_endio(r1_bio); } } } - rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev); + if (r1_bio->bios[mirror] == NULL) + rdev_dec_pending(conf->mirrors[mirror].rdev, + conf->mddev); /* * Let's see if all mirrored write operations have finished @@ -408,10 +455,11 @@ static void raid1_end_write_request(struct bio *bio, int error) * * The rdev for the device selected will have nr_pending incremented. */ -static int read_balance(conf_t *conf, r1bio_t *r1_bio) +static int read_balance(conf_t *conf, r1bio_t *r1_bio, int *max_sectors) { const sector_t this_sector = r1_bio->sector; - const int sectors = r1_bio->sectors; + int sectors; + int best_good_sectors; int start_disk; int best_disk; int i; @@ -426,8 +474,11 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio) * We take the first readable disk when above the resync window. */ retry: + sectors = r1_bio->sectors; best_disk = -1; best_dist = MaxSector; + best_good_sectors = 0; + if (conf->mddev->recovery_cp < MaxSector && (this_sector + sectors >= conf->next_resync)) { choose_first = 1; @@ -439,6 +490,9 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio) for (i = 0 ; i < conf->raid_disks ; i++) { sector_t dist; + sector_t first_bad; + int bad_sectors; + int disk = start_disk + i; if (disk >= conf->raid_disks) disk -= conf->raid_disks; @@ -461,6 +515,35 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio) /* This is a reasonable device to use. It might * even be best. */ + if (is_badblock(rdev, this_sector, sectors, + &first_bad, &bad_sectors)) { + if (best_dist < MaxSector) + /* already have a better device */ + continue; + if (first_bad <= this_sector) { + /* cannot read here. If this is the 'primary' + * device, then we must not read beyond + * bad_sectors from another device.. + */ + bad_sectors -= (this_sector - first_bad); + if (choose_first && sectors > bad_sectors) + sectors = bad_sectors; + if (best_good_sectors > sectors) + best_good_sectors = sectors; + + } else { + sector_t good_sectors = first_bad - this_sector; + if (good_sectors > best_good_sectors) { + best_good_sectors = good_sectors; + best_disk = disk; + } + if (choose_first) + break; + } + continue; + } else + best_good_sectors = sectors; + dist = abs(this_sector - conf->mirrors[disk].head_position); if (choose_first /* Don't change to another disk for sequential reads */ @@ -489,10 +572,12 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio) rdev_dec_pending(rdev, conf->mddev); goto retry; } + sectors = best_good_sectors; conf->next_seq_sect = this_sector + sectors; conf->last_used = best_disk; } rcu_read_unlock(); + *max_sectors = sectors; return best_disk; } @@ -672,30 +757,31 @@ static void alloc_behind_pages(struct bio *bio, r1bio_t *r1_bio) { int i; struct bio_vec *bvec; - struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page*), + struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec), GFP_NOIO); - if (unlikely(!pages)) + if (unlikely(!bvecs)) return; bio_for_each_segment(bvec, bio, i) { - pages[i] = alloc_page(GFP_NOIO); - if (unlikely(!pages[i])) + bvecs[i] = *bvec; + bvecs[i].bv_page = alloc_page(GFP_NOIO); + if (unlikely(!bvecs[i].bv_page)) goto do_sync_io; - memcpy(kmap(pages[i]) + bvec->bv_offset, - kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len); - kunmap(pages[i]); + memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset, + kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len); + kunmap(bvecs[i].bv_page); kunmap(bvec->bv_page); } - r1_bio->behind_pages = pages; + r1_bio->behind_bvecs = bvecs; r1_bio->behind_page_count = bio->bi_vcnt; set_bit(R1BIO_BehindIO, &r1_bio->state); return; do_sync_io: for (i = 0; i < bio->bi_vcnt; i++) - if (pages[i]) - put_page(pages[i]); - kfree(pages); + if (bvecs[i].bv_page) + put_page(bvecs[i].bv_page); + kfree(bvecs); PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size); } @@ -705,7 +791,7 @@ static int make_request(mddev_t *mddev, struct bio * bio) mirror_info_t *mirror; r1bio_t *r1_bio; struct bio *read_bio; - int i, targets = 0, disks; + int i, disks; struct bitmap *bitmap; unsigned long flags; const int rw = bio_data_dir(bio); @@ -713,6 +799,9 @@ static int make_request(mddev_t *mddev, struct bio * bio) const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA)); mdk_rdev_t *blocked_rdev; int plugged; + int first_clone; + int sectors_handled; + int max_sectors; /* * Register the new request and wait if the reconstruction @@ -759,11 +848,24 @@ static int make_request(mddev_t *mddev, struct bio * bio) r1_bio->mddev = mddev; r1_bio->sector = bio->bi_sector; + /* We might need to issue multiple reads to different + * devices if there are bad blocks around, so we keep + * track of the number of reads in bio->bi_phys_segments. + * If this is 0, there is only one r1_bio and no locking + * will be needed when requests complete. If it is + * non-zero, then it is the number of not-completed requests. + */ + bio->bi_phys_segments = 0; + clear_bit(BIO_SEG_VALID, &bio->bi_flags); + if (rw == READ) { /* * read balancing logic: */ - int rdisk = read_balance(conf, r1_bio); + int rdisk; + +read_again: + rdisk = read_balance(conf, r1_bio, &max_sectors); if (rdisk < 0) { /* couldn't find anywhere to read from */ @@ -784,6 +886,8 @@ static int make_request(mddev_t *mddev, struct bio * bio) r1_bio->read_disk = rdisk; read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev); + md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector, + max_sectors); r1_bio->bios[rdisk] = read_bio; @@ -793,16 +897,52 @@ static int make_request(mddev_t *mddev, struct bio * bio) read_bio->bi_rw = READ | do_sync; read_bio->bi_private = r1_bio; - generic_make_request(read_bio); + if (max_sectors < r1_bio->sectors) { + /* could not read all from this device, so we will + * need another r1_bio. + */ + + sectors_handled = (r1_bio->sector + max_sectors + - bio->bi_sector); + r1_bio->sectors = max_sectors; + spin_lock_irq(&conf->device_lock); + if (bio->bi_phys_segments == 0) + bio->bi_phys_segments = 2; + else + bio->bi_phys_segments++; + spin_unlock_irq(&conf->device_lock); + /* Cannot call generic_make_request directly + * as that will be queued in __make_request + * and subsequent mempool_alloc might block waiting + * for it. So hand bio over to raid1d. + */ + reschedule_retry(r1_bio); + + r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO); + + r1_bio->master_bio = bio; + r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled; + r1_bio->state = 0; + r1_bio->mddev = mddev; + r1_bio->sector = bio->bi_sector + sectors_handled; + goto read_again; + } else + generic_make_request(read_bio); return 0; } /* * WRITE: */ - /* first select target devices under spinlock and + /* first select target devices under rcu_lock and * inc refcount on their rdev. Record them by setting * bios[x] to bio + * If there are known/acknowledged bad blocks on any device on + * which we have seen a write error, we want to avoid writing those + * blocks. + * This potentially requires several writes to write around + * the bad blocks. Each set of writes gets it's own r1bio + * with a set of bios attached. */ plugged = mddev_check_plugged(mddev); @@ -810,6 +950,7 @@ static int make_request(mddev_t *mddev, struct bio * bio) retry_write: blocked_rdev = NULL; rcu_read_lock(); + max_sectors = r1_bio->sectors; for (i = 0; i < disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { @@ -817,17 +958,56 @@ static int make_request(mddev_t *mddev, struct bio * bio) blocked_rdev = rdev; break; } - if (rdev && !test_bit(Faulty, &rdev->flags)) { - atomic_inc(&rdev->nr_pending); - if (test_bit(Faulty, &rdev->flags)) { + r1_bio->bios[i] = NULL; + if (!rdev || test_bit(Faulty, &rdev->flags)) { + set_bit(R1BIO_Degraded, &r1_bio->state); + continue; + } + + atomic_inc(&rdev->nr_pending); + if (test_bit(WriteErrorSeen, &rdev->flags)) { + sector_t first_bad; + int bad_sectors; + int is_bad; + + is_bad = is_badblock(rdev, r1_bio->sector, + max_sectors, + &first_bad, &bad_sectors); + if (is_bad < 0) { + /* mustn't write here until the bad block is + * acknowledged*/ + set_bit(BlockedBadBlocks, &rdev->flags); + blocked_rdev = rdev; + break; + } + if (is_bad && first_bad <= r1_bio->sector) { + /* Cannot write here at all */ + bad_sectors -= (r1_bio->sector - first_bad); + if (bad_sectors < max_sectors) + /* mustn't write more than bad_sectors + * to other devices yet + */ + max_sectors = bad_sectors; rdev_dec_pending(rdev, mddev); - r1_bio->bios[i] = NULL; - } else { - r1_bio->bios[i] = bio; - targets++; + /* We don't set R1BIO_Degraded as that + * only applies if the disk is + * missing, so it might be re-added, + * and we want to know to recover this + * chunk. + * In this case the device is here, + * and the fact that this chunk is not + * in-sync is recorded in the bad + * block log + */ + continue; } - } else - r1_bio->bios[i] = NULL; + if (is_bad) { + int good_sectors = first_bad - r1_bio->sector; + if (good_sectors < max_sectors) + max_sectors = good_sectors; + } + } + r1_bio->bios[i] = bio; } rcu_read_unlock(); @@ -838,51 +1018,57 @@ static int make_request(mddev_t *mddev, struct bio * bio) for (j = 0; j < i; j++) if (r1_bio->bios[j]) rdev_dec_pending(conf->mirrors[j].rdev, mddev); - + r1_bio->state = 0; allow_barrier(conf); md_wait_for_blocked_rdev(blocked_rdev, mddev); wait_barrier(conf); goto retry_write; } - BUG_ON(targets == 0); /* we never fail the last device */ - - if (targets < conf->raid_disks) { - /* array is degraded, we will not clear the bitmap - * on I/O completion (see raid1_end_write_request) */ - set_bit(R1BIO_Degraded, &r1_bio->state); + if (max_sectors < r1_bio->sectors) { + /* We are splitting this write into multiple parts, so + * we need to prepare for allocating another r1_bio. + */ + r1_bio->sectors = max_sectors; + spin_lock_irq(&conf->device_lock); + if (bio->bi_phys_segments == 0) + bio->bi_phys_segments = 2; + else + bio->bi_phys_segments++; + spin_unlock_irq(&conf->device_lock); } - - /* do behind I/O ? - * Not if there are too many, or cannot allocate memory, - * or a reader on WriteMostly is waiting for behind writes - * to flush */ - if (bitmap && - (atomic_read(&bitmap->behind_writes) - < mddev->bitmap_info.max_write_behind) && - !waitqueue_active(&bitmap->behind_wait)) - alloc_behind_pages(bio, r1_bio); + sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector; atomic_set(&r1_bio->remaining, 1); atomic_set(&r1_bio->behind_remaining, 0); - bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors, - test_bit(R1BIO_BehindIO, &r1_bio->state)); + first_clone = 1; for (i = 0; i < disks; i++) { struct bio *mbio; if (!r1_bio->bios[i]) continue; mbio = bio_clone_mddev(bio, GFP_NOIO, mddev); - r1_bio->bios[i] = mbio; - - mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset; - mbio->bi_bdev = conf->mirrors[i].rdev->bdev; - mbio->bi_end_io = raid1_end_write_request; - mbio->bi_rw = WRITE | do_flush_fua | do_sync; - mbio->bi_private = r1_bio; - - if (r1_bio->behind_pages) { + md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors); + + if (first_clone) { + /* do behind I/O ? + * Not if there are too many, or cannot + * allocate memory, or a reader on WriteMostly + * is waiting for behind writes to flush */ + if (bitmap && + (atomic_read(&bitmap->behind_writes) + < mddev->bitmap_info.max_write_behind) && + !waitqueue_active(&bitmap->behind_wait)) + alloc_behind_pages(mbio, r1_bio); + + bitmap_startwrite(bitmap, r1_bio->sector, + r1_bio->sectors, + test_bit(R1BIO_BehindIO, + &r1_bio->state)); + first_clone = 0; + } + if (r1_bio->behind_bvecs) { struct bio_vec *bvec; int j; @@ -894,11 +1080,20 @@ static int make_request(mddev_t *mddev, struct bio * bio) * them all */ __bio_for_each_segment(bvec, mbio, j, 0) - bvec->bv_page = r1_bio->behind_pages[j]; + bvec->bv_page = r1_bio->behind_bvecs[j].bv_page; if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags)) atomic_inc(&r1_bio->behind_remaining); } + r1_bio->bios[i] = mbio; + + mbio->bi_sector = (r1_bio->sector + + conf->mirrors[i].rdev->data_offset); + mbio->bi_bdev = conf->mirrors[i].rdev->bdev; + mbio->bi_end_io = raid1_end_write_request; + mbio->bi_rw = WRITE | do_flush_fua | do_sync; + mbio->bi_private = r1_bio; + atomic_inc(&r1_bio->remaining); spin_lock_irqsave(&conf->device_lock, flags); bio_list_add(&conf->pending_bio_list, mbio); @@ -909,6 +1104,19 @@ static int make_request(mddev_t *mddev, struct bio * bio) /* In case raid1d snuck in to freeze_array */ wake_up(&conf->wait_barrier); + if (sectors_handled < (bio->bi_size >> 9)) { + /* We need another r1_bio. It has already been counted + * in bio->bi_phys_segments + */ + r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO); + r1_bio->master_bio = bio; + r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled; + r1_bio->state = 0; + r1_bio->mddev = mddev; + r1_bio->sector = bio->bi_sector + sectors_handled; + goto retry_write; + } + if (do_sync || !bitmap || !plugged) md_wakeup_thread(mddev->thread); @@ -952,9 +1160,10 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev) * However don't try a recovery from this drive as * it is very likely to fail. */ - mddev->recovery_disabled = 1; + conf->recovery_disabled = mddev->recovery_disabled; return; } + set_bit(Blocked, &rdev->flags); if (test_and_clear_bit(In_sync, &rdev->flags)) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); @@ -1027,7 +1236,7 @@ static int raid1_spare_active(mddev_t *mddev) && !test_bit(Faulty, &rdev->flags) && !test_and_set_bit(In_sync, &rdev->flags)) { count++; - sysfs_notify_dirent(rdev->sysfs_state); + sysfs_notify_dirent_safe(rdev->sysfs_state); } } spin_lock_irqsave(&conf->device_lock, flags); @@ -1048,6 +1257,9 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) int first = 0; int last = mddev->raid_disks - 1; + if (mddev->recovery_disabled == conf->recovery_disabled) + return -EBUSY; + if (rdev->raid_disk >= 0) first = last = rdev->raid_disk; @@ -1103,7 +1315,7 @@ static int raid1_remove_disk(mddev_t *mddev, int number) * is not possible. */ if (!test_bit(Faulty, &rdev->flags) && - !mddev->recovery_disabled && + mddev->recovery_disabled != conf->recovery_disabled && mddev->degraded < conf->raid_disks) { err = -EBUSY; goto abort; @@ -1155,6 +1367,8 @@ static void end_sync_write(struct bio *bio, int error) conf_t *conf = mddev->private; int i; int mirror=0; + sector_t first_bad; + int bad_sectors; for (i = 0; i < conf->raid_disks; i++) if (r1_bio->bios[i] == bio) { @@ -1172,18 +1386,48 @@ static void end_sync_write(struct bio *bio, int error) s += sync_blocks; sectors_to_go -= sync_blocks; } while (sectors_to_go > 0); - md_error(mddev, conf->mirrors[mirror].rdev); - } + set_bit(WriteErrorSeen, + &conf->mirrors[mirror].rdev->flags); + set_bit(R1BIO_WriteError, &r1_bio->state); + } else if (is_badblock(conf->mirrors[mirror].rdev, + r1_bio->sector, + r1_bio->sectors, + &first_bad, &bad_sectors) && + !is_badblock(conf->mirrors[r1_bio->read_disk].rdev, + r1_bio->sector, + r1_bio->sectors, + &first_bad, &bad_sectors) + ) + set_bit(R1BIO_MadeGood, &r1_bio->state); update_head_pos(mirror, r1_bio); if (atomic_dec_and_test(&r1_bio->remaining)) { - sector_t s = r1_bio->sectors; - put_buf(r1_bio); - md_done_sync(mddev, s, uptodate); + int s = r1_bio->sectors; + if (test_bit(R1BIO_MadeGood, &r1_bio->state) || + test_bit(R1BIO_WriteError, &r1_bio->state)) + reschedule_retry(r1_bio); + else { + put_buf(r1_bio); + md_done_sync(mddev, s, uptodate); + } } } +static int r1_sync_page_io(mdk_rdev_t *rdev, sector_t sector, + int sectors, struct page *page, int rw) +{ + if (sync_page_io(rdev, sector, sectors << 9, page, rw, false)) + /* success */ + return 1; + if (rw == WRITE) + set_bit(WriteErrorSeen, &rdev->flags); + /* need to record an error - either for the block or the device */ + if (!rdev_set_badblocks(rdev, sector, sectors, 0)) + md_error(rdev->mddev, rdev); + return 0; +} + static int fix_sync_read_error(r1bio_t *r1_bio) { /* Try some synchronous reads of other devices to get @@ -1193,6 +1437,9 @@ static int fix_sync_read_error(r1bio_t *r1_bio) * We don't need to freeze the array, because being in an * active sync request, there is no normal IO, and * no overlapping syncs. + * We don't need to check is_badblock() again as we + * made sure that anything with a bad block in range + * will have bi_end_io clear. */ mddev_t *mddev = r1_bio->mddev; conf_t *conf = mddev->private; @@ -1217,9 +1464,7 @@ static int fix_sync_read_error(r1bio_t *r1_bio) * active, and resync is currently active */ rdev = conf->mirrors[d].rdev; - if (sync_page_io(rdev, - sect, - s<<9, + if (sync_page_io(rdev, sect, s<<9, bio->bi_io_vec[idx].bv_page, READ, false)) { success = 1; @@ -1233,16 +1478,36 @@ static int fix_sync_read_error(r1bio_t *r1_bio) if (!success) { char b[BDEVNAME_SIZE]; - /* Cannot read from anywhere, array is toast */ - md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev); + int abort = 0; + /* Cannot read from anywhere, this block is lost. + * Record a bad block on each device. If that doesn't + * work just disable and interrupt the recovery. + * Don't fail devices as that won't really help. + */ printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error" " for block %llu\n", mdname(mddev), bdevname(bio->bi_bdev, b), (unsigned long long)r1_bio->sector); - md_done_sync(mddev, r1_bio->sectors, 0); - put_buf(r1_bio); - return 0; + for (d = 0; d < conf->raid_disks; d++) { + rdev = conf->mirrors[d].rdev; + if (!rdev || test_bit(Faulty, &rdev->flags)) + continue; + if (!rdev_set_badblocks(rdev, sect, s, 0)) + abort = 1; + } + if (abort) { + mddev->recovery_disabled = 1; + set_bit(MD_RECOVERY_INTR, &mddev->recovery); + md_done_sync(mddev, r1_bio->sectors, 0); + put_buf(r1_bio); + return 0; + } + /* Try next page */ + sectors -= s; + sect += s; + idx++; + continue; } start = d; @@ -1254,16 +1519,12 @@ static int fix_sync_read_error(r1bio_t *r1_bio) if (r1_bio->bios[d]->bi_end_io != end_sync_read) continue; rdev = conf->mirrors[d].rdev; - if (sync_page_io(rdev, - sect, - s<<9, - bio->bi_io_vec[idx].bv_page, - WRITE, false) == 0) { + if (r1_sync_page_io(rdev, sect, s, + bio->bi_io_vec[idx].bv_page, + WRITE) == 0) { r1_bio->bios[d]->bi_end_io = NULL; rdev_dec_pending(rdev, mddev); - md_error(mddev, rdev); - } else - atomic_add(s, &rdev->corrected_errors); + } } d = start; while (d != r1_bio->read_disk) { @@ -1273,12 +1534,10 @@ static int fix_sync_read_error(r1bio_t *r1_bio) if (r1_bio->bios[d]->bi_end_io != end_sync_read) continue; rdev = conf->mirrors[d].rdev; - if (sync_page_io(rdev, - sect, - s<<9, - bio->bi_io_vec[idx].bv_page, - READ, false) == 0) - md_error(mddev, rdev); + if (r1_sync_page_io(rdev, sect, s, + bio->bi_io_vec[idx].bv_page, + READ) != 0) + atomic_add(s, &rdev->corrected_errors); } sectors -= s; sect += s; @@ -1420,7 +1679,7 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio) * * 1. Retries failed read operations on working mirrors. * 2. Updates the raid superblock when problems encounter. - * 3. Performs writes following reads for array syncronising. + * 3. Performs writes following reads for array synchronising. */ static void fix_read_error(conf_t *conf, int read_disk, @@ -1443,9 +1702,14 @@ static void fix_read_error(conf_t *conf, int read_disk, * which is the thread that might remove * a device. If raid1d ever becomes multi-threaded.... */ + sector_t first_bad; + int bad_sectors; + rdev = conf->mirrors[d].rdev; if (rdev && test_bit(In_sync, &rdev->flags) && + is_badblock(rdev, sect, s, + &first_bad, &bad_sectors) == 0 && sync_page_io(rdev, sect, s<<9, conf->tmppage, READ, false)) success = 1; @@ -1457,8 +1721,10 @@ static void fix_read_error(conf_t *conf, int read_disk, } while (!success && d != read_disk); if (!success) { - /* Cannot read from anywhere -- bye bye array */ - md_error(mddev, conf->mirrors[read_disk].rdev); + /* Cannot read from anywhere - mark it bad */ + mdk_rdev_t *rdev = conf->mirrors[read_disk].rdev; + if (!rdev_set_badblocks(rdev, sect, s, 0)) + md_error(mddev, rdev); break; } /* write it back and re-read */ @@ -1469,13 +1735,9 @@ static void fix_read_error(conf_t *conf, int read_disk, d--; rdev = conf->mirrors[d].rdev; if (rdev && - test_bit(In_sync, &rdev->flags)) { - if (sync_page_io(rdev, sect, s<<9, - conf->tmppage, WRITE, false) - == 0) - /* Well, this device is dead */ - md_error(mddev, rdev); - } + test_bit(In_sync, &rdev->flags)) + r1_sync_page_io(rdev, sect, s, + conf->tmppage, WRITE); } d = start; while (d != read_disk) { @@ -1486,12 +1748,8 @@ static void fix_read_error(conf_t *conf, int read_disk, rdev = conf->mirrors[d].rdev; if (rdev && test_bit(In_sync, &rdev->flags)) { - if (sync_page_io(rdev, sect, s<<9, - conf->tmppage, READ, false) - == 0) - /* Well, this device is dead */ - md_error(mddev, rdev); - else { + if (r1_sync_page_io(rdev, sect, s, + conf->tmppage, READ)) { atomic_add(s, &rdev->corrected_errors); printk(KERN_INFO "md/raid1:%s: read error corrected " @@ -1508,21 +1766,255 @@ static void fix_read_error(conf_t *conf, int read_disk, } } +static void bi_complete(struct bio *bio, int error) +{ + complete((struct completion *)bio->bi_private); +} + +static int submit_bio_wait(int rw, struct bio *bio) +{ + struct completion event; + rw |= REQ_SYNC; + + init_completion(&event); + bio->bi_private = &event; + bio->bi_end_io = bi_complete; + submit_bio(rw, bio); + wait_for_completion(&event); + + return test_bit(BIO_UPTODATE, &bio->bi_flags); +} + +static int narrow_write_error(r1bio_t *r1_bio, int i) +{ + mddev_t *mddev = r1_bio->mddev; + conf_t *conf = mddev->private; + mdk_rdev_t *rdev = conf->mirrors[i].rdev; + int vcnt, idx; + struct bio_vec *vec; + + /* bio has the data to be written to device 'i' where + * we just recently had a write error. + * We repeatedly clone the bio and trim down to one block, + * then try the write. Where the write fails we record + * a bad block. + * It is conceivable that the bio doesn't exactly align with + * blocks. We must handle this somehow. + * + * We currently own a reference on the rdev. + */ + + int block_sectors; + sector_t sector; + int sectors; + int sect_to_write = r1_bio->sectors; + int ok = 1; + + if (rdev->badblocks.shift < 0) + return 0; + + block_sectors = 1 << rdev->badblocks.shift; + sector = r1_bio->sector; + sectors = ((sector + block_sectors) + & ~(sector_t)(block_sectors - 1)) + - sector; + + if (test_bit(R1BIO_BehindIO, &r1_bio->state)) { + vcnt = r1_bio->behind_page_count; + vec = r1_bio->behind_bvecs; + idx = 0; + while (vec[idx].bv_page == NULL) + idx++; + } else { + vcnt = r1_bio->master_bio->bi_vcnt; + vec = r1_bio->master_bio->bi_io_vec; + idx = r1_bio->master_bio->bi_idx; + } + while (sect_to_write) { + struct bio *wbio; + if (sectors > sect_to_write) + sectors = sect_to_write; + /* Write at 'sector' for 'sectors'*/ + + wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev); + memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec)); + wbio->bi_sector = r1_bio->sector; + wbio->bi_rw = WRITE; + wbio->bi_vcnt = vcnt; + wbio->bi_size = r1_bio->sectors << 9; + wbio->bi_idx = idx; + + md_trim_bio(wbio, sector - r1_bio->sector, sectors); + wbio->bi_sector += rdev->data_offset; + wbio->bi_bdev = rdev->bdev; + if (submit_bio_wait(WRITE, wbio) == 0) + /* failure! */ + ok = rdev_set_badblocks(rdev, sector, + sectors, 0) + && ok; + + bio_put(wbio); + sect_to_write -= sectors; + sector += sectors; + sectors = block_sectors; + } + return ok; +} + +static void handle_sync_write_finished(conf_t *conf, r1bio_t *r1_bio) +{ + int m; + int s = r1_bio->sectors; + for (m = 0; m < conf->raid_disks ; m++) { + mdk_rdev_t *rdev = conf->mirrors[m].rdev; + struct bio *bio = r1_bio->bios[m]; + if (bio->bi_end_io == NULL) + continue; + if (test_bit(BIO_UPTODATE, &bio->bi_flags) && + test_bit(R1BIO_MadeGood, &r1_bio->state)) { + rdev_clear_badblocks(rdev, r1_bio->sector, s); + } + if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && + test_bit(R1BIO_WriteError, &r1_bio->state)) { + if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0)) + md_error(conf->mddev, rdev); + } + } + put_buf(r1_bio); + md_done_sync(conf->mddev, s, 1); +} + +static void handle_write_finished(conf_t *conf, r1bio_t *r1_bio) +{ + int m; + for (m = 0; m < conf->raid_disks ; m++) + if (r1_bio->bios[m] == IO_MADE_GOOD) { + mdk_rdev_t *rdev = conf->mirrors[m].rdev; + rdev_clear_badblocks(rdev, + r1_bio->sector, + r1_bio->sectors); + rdev_dec_pending(rdev, conf->mddev); + } else if (r1_bio->bios[m] != NULL) { + /* This drive got a write error. We need to + * narrow down and record precise write + * errors. + */ + if (!narrow_write_error(r1_bio, m)) { + md_error(conf->mddev, + conf->mirrors[m].rdev); + /* an I/O failed, we can't clear the bitmap */ + set_bit(R1BIO_Degraded, &r1_bio->state); + } + rdev_dec_pending(conf->mirrors[m].rdev, + conf->mddev); + } + if (test_bit(R1BIO_WriteError, &r1_bio->state)) + close_write(r1_bio); + raid_end_bio_io(r1_bio); +} + +static void handle_read_error(conf_t *conf, r1bio_t *r1_bio) +{ + int disk; + int max_sectors; + mddev_t *mddev = conf->mddev; + struct bio *bio; + char b[BDEVNAME_SIZE]; + mdk_rdev_t *rdev; + + clear_bit(R1BIO_ReadError, &r1_bio->state); + /* we got a read error. Maybe the drive is bad. Maybe just + * the block and we can fix it. + * We freeze all other IO, and try reading the block from + * other devices. When we find one, we re-write + * and check it that fixes the read error. + * This is all done synchronously while the array is + * frozen + */ + if (mddev->ro == 0) { + freeze_array(conf); + fix_read_error(conf, r1_bio->read_disk, + r1_bio->sector, r1_bio->sectors); + unfreeze_array(conf); + } else + md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev); + + bio = r1_bio->bios[r1_bio->read_disk]; + bdevname(bio->bi_bdev, b); +read_more: + disk = read_balance(conf, r1_bio, &max_sectors); + if (disk == -1) { + printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O" + " read error for block %llu\n", + mdname(mddev), b, (unsigned long long)r1_bio->sector); + raid_end_bio_io(r1_bio); + } else { + const unsigned long do_sync + = r1_bio->master_bio->bi_rw & REQ_SYNC; + if (bio) { + r1_bio->bios[r1_bio->read_disk] = + mddev->ro ? IO_BLOCKED : NULL; + bio_put(bio); + } + r1_bio->read_disk = disk; + bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev); + md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors); + r1_bio->bios[r1_bio->read_disk] = bio; + rdev = conf->mirrors[disk].rdev; + printk_ratelimited(KERN_ERR + "md/raid1:%s: redirecting sector %llu" + " to other mirror: %s\n", + mdname(mddev), + (unsigned long long)r1_bio->sector, + bdevname(rdev->bdev, b)); + bio->bi_sector = r1_bio->sector + rdev->data_offset; + bio->bi_bdev = rdev->bdev; + bio->bi_end_io = raid1_end_read_request; + bio->bi_rw = READ | do_sync; + bio->bi_private = r1_bio; + if (max_sectors < r1_bio->sectors) { + /* Drat - have to split this up more */ + struct bio *mbio = r1_bio->master_bio; + int sectors_handled = (r1_bio->sector + max_sectors + - mbio->bi_sector); + r1_bio->sectors = max_sectors; + spin_lock_irq(&conf->device_lock); + if (mbio->bi_phys_segments == 0) + mbio->bi_phys_segments = 2; + else + mbio->bi_phys_segments++; + spin_unlock_irq(&conf->device_lock); + generic_make_request(bio); + bio = NULL; + + r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO); + + r1_bio->master_bio = mbio; + r1_bio->sectors = (mbio->bi_size >> 9) + - sectors_handled; + r1_bio->state = 0; + set_bit(R1BIO_ReadError, &r1_bio->state); + r1_bio->mddev = mddev; + r1_bio->sector = mbio->bi_sector + sectors_handled; + + goto read_more; + } else + generic_make_request(bio); + } +} + static void raid1d(mddev_t *mddev) { r1bio_t *r1_bio; - struct bio *bio; unsigned long flags; conf_t *conf = mddev->private; struct list_head *head = &conf->retry_list; - mdk_rdev_t *rdev; struct blk_plug plug; md_check_recovery(mddev); blk_start_plug(&plug); for (;;) { - char b[BDEVNAME_SIZE]; if (atomic_read(&mddev->plug_cnt) == 0) flush_pending_writes(conf); @@ -1539,62 +2031,26 @@ static void raid1d(mddev_t *mddev) mddev = r1_bio->mddev; conf = mddev->private; - if (test_bit(R1BIO_IsSync, &r1_bio->state)) - sync_request_write(mddev, r1_bio); - else { - int disk; - - /* we got a read error. Maybe the drive is bad. Maybe just - * the block and we can fix it. - * We freeze all other IO, and try reading the block from - * other devices. When we find one, we re-write - * and check it that fixes the read error. - * This is all done synchronously while the array is - * frozen + if (test_bit(R1BIO_IsSync, &r1_bio->state)) { + if (test_bit(R1BIO_MadeGood, &r1_bio->state) || + test_bit(R1BIO_WriteError, &r1_bio->state)) + handle_sync_write_finished(conf, r1_bio); + else + sync_request_write(mddev, r1_bio); + } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) || + test_bit(R1BIO_WriteError, &r1_bio->state)) + handle_write_finished(conf, r1_bio); + else if (test_bit(R1BIO_ReadError, &r1_bio->state)) + handle_read_error(conf, r1_bio); + else + /* just a partial read to be scheduled from separate + * context */ - if (mddev->ro == 0) { - freeze_array(conf); - fix_read_error(conf, r1_bio->read_disk, - r1_bio->sector, - r1_bio->sectors); - unfreeze_array(conf); - } else - md_error(mddev, - conf->mirrors[r1_bio->read_disk].rdev); - - bio = r1_bio->bios[r1_bio->read_disk]; - if ((disk=read_balance(conf, r1_bio)) == -1) { - printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O" - " read error for block %llu\n", - mdname(mddev), - bdevname(bio->bi_bdev,b), - (unsigned long long)r1_bio->sector); - raid_end_bio_io(r1_bio); - } else { - const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC; - r1_bio->bios[r1_bio->read_disk] = - mddev->ro ? IO_BLOCKED : NULL; - r1_bio->read_disk = disk; - bio_put(bio); - bio = bio_clone_mddev(r1_bio->master_bio, - GFP_NOIO, mddev); - r1_bio->bios[r1_bio->read_disk] = bio; - rdev = conf->mirrors[disk].rdev; - if (printk_ratelimit()) - printk(KERN_ERR "md/raid1:%s: redirecting sector %llu to" - " other mirror: %s\n", - mdname(mddev), - (unsigned long long)r1_bio->sector, - bdevname(rdev->bdev,b)); - bio->bi_sector = r1_bio->sector + rdev->data_offset; - bio->bi_bdev = rdev->bdev; - bio->bi_end_io = raid1_end_read_request; - bio->bi_rw = READ | do_sync; - bio->bi_private = r1_bio; - generic_make_request(bio); - } - } + generic_make_request(r1_bio->bios[r1_bio->read_disk]); + cond_resched(); + if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) + md_check_recovery(mddev); } blk_finish_plug(&plug); } @@ -1636,6 +2092,8 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i int write_targets = 0, read_targets = 0; sector_t sync_blocks; int still_degraded = 0; + int good_sectors = RESYNC_SECTORS; + int min_bad = 0; /* number of sectors that are bad in all devices */ if (!conf->r1buf_pool) if (init_resync(conf)) @@ -1723,36 +2181,89 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i rdev = rcu_dereference(conf->mirrors[i].rdev); if (rdev == NULL || - test_bit(Faulty, &rdev->flags)) { + test_bit(Faulty, &rdev->flags)) { still_degraded = 1; - continue; } else if (!test_bit(In_sync, &rdev->flags)) { bio->bi_rw = WRITE; bio->bi_end_io = end_sync_write; write_targets ++; } else { /* may need to read from here */ - bio->bi_rw = READ; - bio->bi_end_io = end_sync_read; - if (test_bit(WriteMostly, &rdev->flags)) { - if (wonly < 0) - wonly = i; - } else { - if (disk < 0) - disk = i; + sector_t first_bad = MaxSector; + int bad_sectors; + + if (is_badblock(rdev, sector_nr, good_sectors, + &first_bad, &bad_sectors)) { + if (first_bad > sector_nr) + good_sectors = first_bad - sector_nr; + else { + bad_sectors -= (sector_nr - first_bad); + if (min_bad == 0 || + min_bad > bad_sectors) + min_bad = bad_sectors; + } + } + if (sector_nr < first_bad) { + if (test_bit(WriteMostly, &rdev->flags)) { + if (wonly < 0) + wonly = i; + } else { + if (disk < 0) + disk = i; + } + bio->bi_rw = READ; + bio->bi_end_io = end_sync_read; + read_targets++; } - read_targets++; } - atomic_inc(&rdev->nr_pending); - bio->bi_sector = sector_nr + rdev->data_offset; - bio->bi_bdev = rdev->bdev; - bio->bi_private = r1_bio; + if (bio->bi_end_io) { + atomic_inc(&rdev->nr_pending); + bio->bi_sector = sector_nr + rdev->data_offset; + bio->bi_bdev = rdev->bdev; + bio->bi_private = r1_bio; + } } rcu_read_unlock(); if (disk < 0) disk = wonly; r1_bio->read_disk = disk; + if (read_targets == 0 && min_bad > 0) { + /* These sectors are bad on all InSync devices, so we + * need to mark them bad on all write targets + */ + int ok = 1; + for (i = 0 ; i < conf->raid_disks ; i++) + if (r1_bio->bios[i]->bi_end_io == end_sync_write) { + mdk_rdev_t *rdev = + rcu_dereference(conf->mirrors[i].rdev); + ok = rdev_set_badblocks(rdev, sector_nr, + min_bad, 0 + ) && ok; + } + set_bit(MD_CHANGE_DEVS, &mddev->flags); + *skipped = 1; + put_buf(r1_bio); + + if (!ok) { + /* Cannot record the badblocks, so need to + * abort the resync. + * If there are multiple read targets, could just + * fail the really bad ones ??? + */ + conf->recovery_disabled = mddev->recovery_disabled; + set_bit(MD_RECOVERY_INTR, &mddev->recovery); + return 0; + } else + return min_bad; + + } + if (min_bad > 0 && min_bad < good_sectors) { + /* only resync enough to reach the next bad->good + * transition */ + good_sectors = min_bad; + } + if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0) /* extra read targets are also write targets */ write_targets += read_targets-1; @@ -1769,6 +2280,8 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i if (max_sector > mddev->resync_max) max_sector = mddev->resync_max; /* Don't do IO beyond here */ + if (max_sector > sector_nr + good_sectors) + max_sector = sector_nr + good_sectors; nr_sectors = 0; sync_blocks = 0; do { @@ -2154,18 +2667,13 @@ static int raid1_reshape(mddev_t *mddev) for (d = d2 = 0; d < conf->raid_disks; d++) { mdk_rdev_t *rdev = conf->mirrors[d].rdev; if (rdev && rdev->raid_disk != d2) { - char nm[20]; - sprintf(nm, "rd%d", rdev->raid_disk); - sysfs_remove_link(&mddev->kobj, nm); + sysfs_unlink_rdev(mddev, rdev); rdev->raid_disk = d2; - sprintf(nm, "rd%d", rdev->raid_disk); - sysfs_remove_link(&mddev->kobj, nm); - if (sysfs_create_link(&mddev->kobj, - &rdev->kobj, nm)) + sysfs_unlink_rdev(mddev, rdev); + if (sysfs_link_rdev(mddev, rdev)) printk(KERN_WARNING - "md/raid1:%s: cannot register " - "%s\n", - mdname(mddev), nm); + "md/raid1:%s: cannot register rd%d\n", + mdname(mddev), rdev->raid_disk); } if (rdev) newmirrors[d2++].rdev = rdev; |