diff options
| -rw-r--r-- | drivers/md/md.c | 415 | ||||
| -rw-r--r-- | drivers/md/md.h | 48 |
2 files changed, 459 insertions, 4 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 4279b3b..463a392 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -1952,6 +1952,9 @@ static void unbind_rdev_from_array(mdk_rdev_t * rdev) sysfs_remove_link(&rdev->kobj, "block"); sysfs_put(rdev->sysfs_state); rdev->sysfs_state = NULL; + kfree(rdev->badblocks.page); + rdev->badblocks.count = 0; + rdev->badblocks.page = NULL; /* We need to delay this, otherwise we can deadlock when * writing to 'remove' to "dev/state". We also need * to delay it due to rcu usage. @@ -2778,7 +2781,7 @@ static struct kobj_type rdev_ktype = { .default_attrs = rdev_default_attrs, }; -void md_rdev_init(mdk_rdev_t *rdev) +int md_rdev_init(mdk_rdev_t *rdev) { rdev->desc_nr = -1; rdev->saved_raid_disk = -1; @@ -2794,6 +2797,19 @@ void md_rdev_init(mdk_rdev_t *rdev) INIT_LIST_HEAD(&rdev->same_set); init_waitqueue_head(&rdev->blocked_wait); + + /* Add space to store bad block list. + * This reserves the space even on arrays where it cannot + * be used - I wonder if that matters + */ + rdev->badblocks.count = 0; + rdev->badblocks.shift = 0; + rdev->badblocks.page = kmalloc(PAGE_SIZE, GFP_KERNEL); + seqlock_init(&rdev->badblocks.lock); + if (rdev->badblocks.page == NULL) + return -ENOMEM; + + return 0; } EXPORT_SYMBOL_GPL(md_rdev_init); /* @@ -2819,8 +2835,11 @@ static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_mi return ERR_PTR(-ENOMEM); } - md_rdev_init(rdev); - if ((err = alloc_disk_sb(rdev))) + err = md_rdev_init(rdev); + if (err) + goto abort_free; + err = alloc_disk_sb(rdev); + if (err) goto abort_free; err = lock_rdev(rdev, newdev, super_format == -2); @@ -2865,6 +2884,7 @@ abort_free: unlock_rdev(rdev); free_disk_sb(rdev); } + kfree(rdev->badblocks.page); kfree(rdev); return ERR_PTR(err); } @@ -7327,6 +7347,395 @@ void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev) } EXPORT_SYMBOL(md_wait_for_blocked_rdev); + +/* Bad block management. + * We can record which blocks on each device are 'bad' and so just + * fail those blocks, or that stripe, rather than the whole device. + * Entries in the bad-block table are 64bits wide. This comprises: + * Length of bad-range, in sectors: 0-511 for lengths 1-512 + * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes) + * A 'shift' can be set so that larger blocks are tracked and + * consequently larger devices can be covered. + * 'Acknowledged' flag - 1 bit. - the most significant bit. + * + * Locking of the bad-block table uses a seqlock so md_is_badblock + * might need to retry if it is very unlucky. + * We will sometimes want to check for bad blocks in a bi_end_io function, + * so we use the write_seqlock_irq variant. + * + * When looking for a bad block we specify a range and want to + * know if any block in the range is bad. So we binary-search + * to the last range that starts at-or-before the given endpoint, + * (or "before the sector after the target range") + * then see if it ends after the given start. + * We return + * 0 if there are no known bad blocks in the range + * 1 if there are known bad block which are all acknowledged + * -1 if there are bad blocks which have not yet been acknowledged in metadata. + * plus the start/length of the first bad section we overlap. + */ +int md_is_badblock(struct badblocks *bb, sector_t s, int sectors, + sector_t *first_bad, int *bad_sectors) +{ + int hi; + int lo = 0; + u64 *p = bb->page; + int rv = 0; + sector_t target = s + sectors; + unsigned seq; + + if (bb->shift > 0) { + /* round the start down, and the end up */ + s >>= bb->shift; + target += (1<<bb->shift) - 1; + target >>= bb->shift; + sectors = target - s; + } + /* 'target' is now the first block after the bad range */ + +retry: + seq = read_seqbegin(&bb->lock); + + hi = bb->count; + + /* Binary search between lo and hi for 'target' + * i.e. for the last range that starts before 'target' + */ + /* INVARIANT: ranges before 'lo' and at-or-after 'hi' + * are known not to be the last range before target. + * VARIANT: hi-lo is the number of possible + * ranges, and decreases until it reaches 1 + */ + while (hi - lo > 1) { + int mid = (lo + hi) / 2; + sector_t a = BB_OFFSET(p[mid]); + if (a < target) + /* This could still be the one, earlier ranges + * could not. */ + lo = mid; + else + /* This and later ranges are definitely out. */ + hi = mid; + } + /* 'lo' might be the last that started before target, but 'hi' isn't */ + if (hi > lo) { + /* need to check all range that end after 's' to see if + * any are unacknowledged. + */ + while (lo >= 0 && + BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) { + if (BB_OFFSET(p[lo]) < target) { + /* starts before the end, and finishes after + * the start, so they must overlap + */ + if (rv != -1 && BB_ACK(p[lo])) + rv = 1; + else + rv = -1; + *first_bad = BB_OFFSET(p[lo]); + *bad_sectors = BB_LEN(p[lo]); + } + lo--; + } + } + + if (read_seqretry(&bb->lock, seq)) + goto retry; + + return rv; +} +EXPORT_SYMBOL_GPL(md_is_badblock); + +/* + * Add a range of bad blocks to the table. + * This might extend the table, or might contract it + * if two adjacent ranges can be merged. + * We binary-search to find the 'insertion' point, then + * decide how best to handle it. + */ +static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors, + int acknowledged) +{ + u64 *p; + int lo, hi; + int rv = 1; + + if (bb->shift < 0) + /* badblocks are disabled */ + return 0; + + if (bb->shift) { + /* round the start down, and the end up */ + sector_t next = s + sectors; + s >>= bb->shift; + next += (1<<bb->shift) - 1; + next >>= bb->shift; + sectors = next - s; + } + + write_seqlock_irq(&bb->lock); + + p = bb->page; + lo = 0; + hi = bb->count; + /* Find the last range that starts at-or-before 's' */ + while (hi - lo > 1) { + int mid = (lo + hi) / 2; + sector_t a = BB_OFFSET(p[mid]); + if (a <= s) + lo = mid; + else + hi = mid; + } + if (hi > lo && BB_OFFSET(p[lo]) > s) + hi = lo; + + if (hi > lo) { + /* we found a range that might merge with the start + * of our new range + */ + sector_t a = BB_OFFSET(p[lo]); + sector_t e = a + BB_LEN(p[lo]); + int ack = BB_ACK(p[lo]); + if (e >= s) { + /* Yes, we can merge with a previous range */ + if (s == a && s + sectors >= e) + /* new range covers old */ + ack = acknowledged; + else + ack = ack && acknowledged; + + if (e < s + sectors) + e = s + sectors; + if (e - a <= BB_MAX_LEN) { + p[lo] = BB_MAKE(a, e-a, ack); + s = e; + } else { + /* does not all fit in one range, + * make p[lo] maximal + */ + if (BB_LEN(p[lo]) != BB_MAX_LEN) + p[lo] = BB_MAKE(a, BB_MAX_LEN, ack); + s = a + BB_MAX_LEN; + } + sectors = e - s; + } + } + if (sectors && hi < bb->count) { + /* 'hi' points to the first range that starts after 's'. + * Maybe we can merge with the start of that range */ + sector_t a = BB_OFFSET(p[hi]); + sector_t e = a + BB_LEN(p[hi]); + int ack = BB_ACK(p[hi]); + if (a <= s + sectors) { + /* merging is possible */ + if (e <= s + sectors) { + /* full overlap */ + e = s + sectors; + ack = acknowledged; + } else + ack = ack && acknowledged; + + a = s; + if (e - a <= BB_MAX_LEN) { + p[hi] = BB_MAKE(a, e-a, ack); + s = e; + } else { + p[hi] = BB_MAKE(a, BB_MAX_LEN, ack); + s = a + BB_MAX_LEN; + } + sectors = e - s; + lo = hi; + hi++; + } + } + if (sectors == 0 && hi < bb->count) { + /* we might be able to combine lo and hi */ + /* Note: 's' is at the end of 'lo' */ + sector_t a = BB_OFFSET(p[hi]); + int lolen = BB_LEN(p[lo]); + int hilen = BB_LEN(p[hi]); + int newlen = lolen + hilen - (s - a); + if (s >= a && newlen < BB_MAX_LEN) { + /* yes, we can combine them */ + int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]); + p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack); + memmove(p + hi, p + hi + 1, + (bb->count - hi - 1) * 8); + bb->count--; + } + } + while (sectors) { + /* didn't merge (it all). + * Need to add a range just before 'hi' */ + if (bb->count >= MD_MAX_BADBLOCKS) { + /* No room for more */ + rv = 0; + break; + } else { + int this_sectors = sectors; + memmove(p + hi + 1, p + hi, + (bb->count - hi) * 8); + bb->count++; + + if (this_sectors > BB_MAX_LEN) + this_sectors = BB_MAX_LEN; + p[hi] = BB_MAKE(s, this_sectors, acknowledged); + sectors -= this_sectors; + s += this_sectors; + } + } + + bb->changed = 1; + write_sequnlock_irq(&bb->lock); + + return rv; +} + +int rdev_set_badblocks(mdk_rdev_t *rdev, sector_t s, int sectors, + int acknowledged) +{ + int rv = md_set_badblocks(&rdev->badblocks, + s + rdev->data_offset, sectors, acknowledged); + if (rv) { + /* Make sure they get written out promptly */ + set_bit(MD_CHANGE_CLEAN, &rdev->mddev->flags); + md_wakeup_thread(rdev->mddev->thread); + } + return rv; +} +EXPORT_SYMBOL_GPL(rdev_set_badblocks); + +/* + * Remove a range of bad blocks from the table. + * This may involve extending the table if we spilt a region, + * but it must not fail. So if the table becomes full, we just + * drop the remove request. + */ +static int md_clear_badblocks(struct badblocks *bb, sector_t s, int sectors) +{ + u64 *p; + int lo, hi; + sector_t target = s + sectors; + int rv = 0; + + if (bb->shift > 0) { + /* When clearing we round the start up and the end down. + * This should not matter as the shift should align with + * the block size and no rounding should ever be needed. + * However it is better the think a block is bad when it + * isn't than to think a block is not bad when it is. + */ + s += (1<<bb->shift) - 1; + s >>= bb->shift; + target >>= bb->shift; + sectors = target - s; + } + + write_seqlock_irq(&bb->lock); + + p = bb->page; + lo = 0; + hi = bb->count; + /* Find the last range that starts before 'target' */ + while (hi - lo > 1) { + int mid = (lo + hi) / 2; + sector_t a = BB_OFFSET(p[mid]); + if (a < target) + lo = mid; + else + hi = mid; + } + if (hi > lo) { + /* p[lo] is the last range that could overlap the + * current range. Earlier ranges could also overlap, + * but only this one can overlap the end of the range. + */ + if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) { + /* Partial overlap, leave the tail of this range */ + int ack = BB_ACK(p[lo]); + sector_t a = BB_OFFSET(p[lo]); + sector_t end = a + BB_LEN(p[lo]); + + if (a < s) { + /* we need to split this range */ + if (bb->count >= MD_MAX_BADBLOCKS) { + rv = 0; + goto out; + } + memmove(p+lo+1, p+lo, (bb->count - lo) * 8); + bb->count++; + p[lo] = BB_MAKE(a, s-a, ack); + lo++; + } + p[lo] = BB_MAKE(target, end - target, ack); + /* there is no longer an overlap */ + hi = lo; + lo--; + } + while (lo >= 0 && + BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) { + /* This range does overlap */ + if (BB_OFFSET(p[lo]) < s) { + /* Keep the early parts of this range. */ + int ack = BB_ACK(p[lo]); + sector_t start = BB_OFFSET(p[lo]); + p[lo] = BB_MAKE(start, s - start, ack); + /* now low doesn't overlap, so.. */ + break; + } + lo--; + } + /* 'lo' is strictly before, 'hi' is strictly after, + * anything between needs to be discarded + */ + if (hi - lo > 1) { + memmove(p+lo+1, p+hi, (bb->count - hi) * 8); + bb->count -= (hi - lo - 1); + } + } + + bb->changed = 1; +out: + write_sequnlock_irq(&bb->lock); + return rv; +} + +int rdev_clear_badblocks(mdk_rdev_t *rdev, sector_t s, int sectors) +{ + return md_clear_badblocks(&rdev->badblocks, + s + rdev->data_offset, + sectors); +} +EXPORT_SYMBOL_GPL(rdev_clear_badblocks); + +/* + * Acknowledge all bad blocks in a list. + * This only succeeds if ->changed is clear. It is used by + * in-kernel metadata updates + */ +void md_ack_all_badblocks(struct badblocks *bb) +{ + if (bb->page == NULL || bb->changed) + /* no point even trying */ + return; + write_seqlock_irq(&bb->lock); + + if (bb->changed == 0) { + u64 *p = bb->page; + int i; + for (i = 0; i < bb->count ; i++) { + if (!BB_ACK(p[i])) { + sector_t start = BB_OFFSET(p[i]); + int len = BB_LEN(p[i]); + p[i] = BB_MAKE(start, len, 1); + } + } + } + write_sequnlock_irq(&bb->lock); +} +EXPORT_SYMBOL_GPL(md_ack_all_badblocks); + static int md_notify_reboot(struct notifier_block *this, unsigned long code, void *x) { diff --git a/drivers/md/md.h b/drivers/md/md.h index 7d906a9..85af843 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -29,6 +29,13 @@ typedef struct mddev_s mddev_t; typedef struct mdk_rdev_s mdk_rdev_t; +/* Bad block numbers are stored sorted in a single page. + * 64bits is used for each block or extent. + * 54 bits are sector number, 9 bits are extent size, + * 1 bit is an 'acknowledged' flag. + */ +#define MD_MAX_BADBLOCKS (PAGE_SIZE/8) + /* * MD's 'extended' device */ @@ -111,8 +118,47 @@ struct mdk_rdev_s struct sysfs_dirent *sysfs_state; /* handle for 'state' * sysfs entry */ + + struct badblocks { + int count; /* count of bad blocks */ + int shift; /* shift from sectors to block size + * a -ve shift means badblocks are + * disabled.*/ + u64 *page; /* badblock list */ + int changed; + seqlock_t lock; + } badblocks; }; +#define BB_LEN_MASK (0x00000000000001FFULL) +#define BB_OFFSET_MASK (0x7FFFFFFFFFFFFE00ULL) +#define BB_ACK_MASK (0x8000000000000000ULL) +#define BB_MAX_LEN 512 +#define BB_OFFSET(x) (((x) & BB_OFFSET_MASK) >> 9) +#define BB_LEN(x) (((x) & BB_LEN_MASK) + 1) +#define BB_ACK(x) (!!((x) & BB_ACK_MASK)) +#define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63)) + +extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors, + sector_t *first_bad, int *bad_sectors); +static inline int is_badblock(mdk_rdev_t *rdev, sector_t s, int sectors, + sector_t *first_bad, int *bad_sectors) +{ + if (unlikely(rdev->badblocks.count)) { + int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s, + sectors, + first_bad, bad_sectors); + if (rv) + *first_bad -= rdev->data_offset; + return rv; + } + return 0; +} +extern int rdev_set_badblocks(mdk_rdev_t *rdev, sector_t s, int sectors, + int acknowledged); +extern int rdev_clear_badblocks(mdk_rdev_t *rdev, sector_t s, int sectors); +extern void md_ack_all_badblocks(struct badblocks *bb); + struct mddev_s { void *private; @@ -517,7 +563,7 @@ extern void mddev_init(mddev_t *mddev); extern int md_run(mddev_t *mddev); extern void md_stop(mddev_t *mddev); extern void md_stop_writes(mddev_t *mddev); -extern void md_rdev_init(mdk_rdev_t *rdev); +extern int md_rdev_init(mdk_rdev_t *rdev); extern void mddev_suspend(mddev_t *mddev); extern void mddev_resume(mddev_t *mddev); |