diff options
Diffstat (limited to 'fs/btrfs/raid56.c')
| -rw-r--r-- | fs/btrfs/raid56.c | 2761 |
1 files changed, 2761 insertions, 0 deletions
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c new file mode 100644 index 000000000..82c8e9913 --- /dev/null +++ b/fs/btrfs/raid56.c @@ -0,0 +1,2761 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2012 Fusion-io All rights reserved. + * Copyright (C) 2012 Intel Corp. All rights reserved. + */ + +#include <linux/sched.h> +#include <linux/bio.h> +#include <linux/slab.h> +#include <linux/blkdev.h> +#include <linux/raid/pq.h> +#include <linux/hash.h> +#include <linux/list_sort.h> +#include <linux/raid/xor.h> +#include <linux/mm.h> +#include "misc.h" +#include "ctree.h" +#include "disk-io.h" +#include "volumes.h" +#include "raid56.h" +#include "async-thread.h" + +/* set when additional merges to this rbio are not allowed */ +#define RBIO_RMW_LOCKED_BIT 1 + +/* + * set when this rbio is sitting in the hash, but it is just a cache + * of past RMW + */ +#define RBIO_CACHE_BIT 2 + +/* + * set when it is safe to trust the stripe_pages for caching + */ +#define RBIO_CACHE_READY_BIT 3 + +#define RBIO_CACHE_SIZE 1024 + +#define BTRFS_STRIPE_HASH_TABLE_BITS 11 + +/* Used by the raid56 code to lock stripes for read/modify/write */ +struct btrfs_stripe_hash { + struct list_head hash_list; + spinlock_t lock; +}; + +/* Used by the raid56 code to lock stripes for read/modify/write */ +struct btrfs_stripe_hash_table { + struct list_head stripe_cache; + spinlock_t cache_lock; + int cache_size; + struct btrfs_stripe_hash table[]; +}; + +/* + * A bvec like structure to present a sector inside a page. + * + * Unlike bvec we don't need bvlen, as it's fixed to sectorsize. + */ +struct sector_ptr { + struct page *page; + unsigned int pgoff:24; + unsigned int uptodate:8; +}; + +static int __raid56_parity_recover(struct btrfs_raid_bio *rbio); +static noinline void finish_rmw(struct btrfs_raid_bio *rbio); +static void rmw_work(struct work_struct *work); +static void read_rebuild_work(struct work_struct *work); +static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio); +static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed); +static void __free_raid_bio(struct btrfs_raid_bio *rbio); +static void index_rbio_pages(struct btrfs_raid_bio *rbio); +static int alloc_rbio_pages(struct btrfs_raid_bio *rbio); + +static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, + int need_check); +static void scrub_parity_work(struct work_struct *work); + +static void start_async_work(struct btrfs_raid_bio *rbio, work_func_t work_func) +{ + INIT_WORK(&rbio->work, work_func); + queue_work(rbio->bioc->fs_info->rmw_workers, &rbio->work); +} + +/* + * the stripe hash table is used for locking, and to collect + * bios in hopes of making a full stripe + */ +int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info) +{ + struct btrfs_stripe_hash_table *table; + struct btrfs_stripe_hash_table *x; + struct btrfs_stripe_hash *cur; + struct btrfs_stripe_hash *h; + int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS; + int i; + + if (info->stripe_hash_table) + return 0; + + /* + * The table is large, starting with order 4 and can go as high as + * order 7 in case lock debugging is turned on. + * + * Try harder to allocate and fallback to vmalloc to lower the chance + * of a failing mount. + */ + table = kvzalloc(struct_size(table, table, num_entries), GFP_KERNEL); + if (!table) + return -ENOMEM; + + spin_lock_init(&table->cache_lock); + INIT_LIST_HEAD(&table->stripe_cache); + + h = table->table; + + for (i = 0; i < num_entries; i++) { + cur = h + i; + INIT_LIST_HEAD(&cur->hash_list); + spin_lock_init(&cur->lock); + } + + x = cmpxchg(&info->stripe_hash_table, NULL, table); + kvfree(x); + return 0; +} + +/* + * caching an rbio means to copy anything from the + * bio_sectors array into the stripe_pages array. We + * use the page uptodate bit in the stripe cache array + * to indicate if it has valid data + * + * once the caching is done, we set the cache ready + * bit. + */ +static void cache_rbio_pages(struct btrfs_raid_bio *rbio) +{ + int i; + int ret; + + ret = alloc_rbio_pages(rbio); + if (ret) + return; + + for (i = 0; i < rbio->nr_sectors; i++) { + /* Some range not covered by bio (partial write), skip it */ + if (!rbio->bio_sectors[i].page) + continue; + + ASSERT(rbio->stripe_sectors[i].page); + memcpy_page(rbio->stripe_sectors[i].page, + rbio->stripe_sectors[i].pgoff, + rbio->bio_sectors[i].page, + rbio->bio_sectors[i].pgoff, + rbio->bioc->fs_info->sectorsize); + rbio->stripe_sectors[i].uptodate = 1; + } + set_bit(RBIO_CACHE_READY_BIT, &rbio->flags); +} + +/* + * we hash on the first logical address of the stripe + */ +static int rbio_bucket(struct btrfs_raid_bio *rbio) +{ + u64 num = rbio->bioc->raid_map[0]; + + /* + * we shift down quite a bit. We're using byte + * addressing, and most of the lower bits are zeros. + * This tends to upset hash_64, and it consistently + * returns just one or two different values. + * + * shifting off the lower bits fixes things. + */ + return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS); +} + +static bool full_page_sectors_uptodate(struct btrfs_raid_bio *rbio, + unsigned int page_nr) +{ + const u32 sectorsize = rbio->bioc->fs_info->sectorsize; + const u32 sectors_per_page = PAGE_SIZE / sectorsize; + int i; + + ASSERT(page_nr < rbio->nr_pages); + + for (i = sectors_per_page * page_nr; + i < sectors_per_page * page_nr + sectors_per_page; + i++) { + if (!rbio->stripe_sectors[i].uptodate) + return false; + } + return true; +} + +/* + * Update the stripe_sectors[] array to use correct page and pgoff + * + * Should be called every time any page pointer in stripes_pages[] got modified. + */ +static void index_stripe_sectors(struct btrfs_raid_bio *rbio) +{ + const u32 sectorsize = rbio->bioc->fs_info->sectorsize; + u32 offset; + int i; + + for (i = 0, offset = 0; i < rbio->nr_sectors; i++, offset += sectorsize) { + int page_index = offset >> PAGE_SHIFT; + + ASSERT(page_index < rbio->nr_pages); + rbio->stripe_sectors[i].page = rbio->stripe_pages[page_index]; + rbio->stripe_sectors[i].pgoff = offset_in_page(offset); + } +} + +static void steal_rbio_page(struct btrfs_raid_bio *src, + struct btrfs_raid_bio *dest, int page_nr) +{ + const u32 sectorsize = src->bioc->fs_info->sectorsize; + const u32 sectors_per_page = PAGE_SIZE / sectorsize; + int i; + + if (dest->stripe_pages[page_nr]) + __free_page(dest->stripe_pages[page_nr]); + dest->stripe_pages[page_nr] = src->stripe_pages[page_nr]; + src->stripe_pages[page_nr] = NULL; + + /* Also update the sector->uptodate bits. */ + for (i = sectors_per_page * page_nr; + i < sectors_per_page * page_nr + sectors_per_page; i++) + dest->stripe_sectors[i].uptodate = true; +} + +/* + * Stealing an rbio means taking all the uptodate pages from the stripe array + * in the source rbio and putting them into the destination rbio. + * + * This will also update the involved stripe_sectors[] which are referring to + * the old pages. + */ +static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest) +{ + int i; + struct page *s; + + if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags)) + return; + + for (i = 0; i < dest->nr_pages; i++) { + s = src->stripe_pages[i]; + if (!s || !full_page_sectors_uptodate(src, i)) + continue; + + steal_rbio_page(src, dest, i); + } + index_stripe_sectors(dest); + index_stripe_sectors(src); +} + +/* + * merging means we take the bio_list from the victim and + * splice it into the destination. The victim should + * be discarded afterwards. + * + * must be called with dest->rbio_list_lock held + */ +static void merge_rbio(struct btrfs_raid_bio *dest, + struct btrfs_raid_bio *victim) +{ + bio_list_merge(&dest->bio_list, &victim->bio_list); + dest->bio_list_bytes += victim->bio_list_bytes; + /* Also inherit the bitmaps from @victim. */ + bitmap_or(&dest->dbitmap, &victim->dbitmap, &dest->dbitmap, + dest->stripe_nsectors); + bio_list_init(&victim->bio_list); +} + +/* + * used to prune items that are in the cache. The caller + * must hold the hash table lock. + */ +static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio) +{ + int bucket = rbio_bucket(rbio); + struct btrfs_stripe_hash_table *table; + struct btrfs_stripe_hash *h; + int freeit = 0; + + /* + * check the bit again under the hash table lock. + */ + if (!test_bit(RBIO_CACHE_BIT, &rbio->flags)) + return; + + table = rbio->bioc->fs_info->stripe_hash_table; + h = table->table + bucket; + + /* hold the lock for the bucket because we may be + * removing it from the hash table + */ + spin_lock(&h->lock); + + /* + * hold the lock for the bio list because we need + * to make sure the bio list is empty + */ + spin_lock(&rbio->bio_list_lock); + + if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) { + list_del_init(&rbio->stripe_cache); + table->cache_size -= 1; + freeit = 1; + + /* if the bio list isn't empty, this rbio is + * still involved in an IO. We take it out + * of the cache list, and drop the ref that + * was held for the list. + * + * If the bio_list was empty, we also remove + * the rbio from the hash_table, and drop + * the corresponding ref + */ + if (bio_list_empty(&rbio->bio_list)) { + if (!list_empty(&rbio->hash_list)) { + list_del_init(&rbio->hash_list); + refcount_dec(&rbio->refs); + BUG_ON(!list_empty(&rbio->plug_list)); + } + } + } + + spin_unlock(&rbio->bio_list_lock); + spin_unlock(&h->lock); + + if (freeit) + __free_raid_bio(rbio); +} + +/* + * prune a given rbio from the cache + */ +static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio) +{ + struct btrfs_stripe_hash_table *table; + unsigned long flags; + + if (!test_bit(RBIO_CACHE_BIT, &rbio->flags)) + return; + + table = rbio->bioc->fs_info->stripe_hash_table; + + spin_lock_irqsave(&table->cache_lock, flags); + __remove_rbio_from_cache(rbio); + spin_unlock_irqrestore(&table->cache_lock, flags); +} + +/* + * remove everything in the cache + */ +static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info) +{ + struct btrfs_stripe_hash_table *table; + unsigned long flags; + struct btrfs_raid_bio *rbio; + + table = info->stripe_hash_table; + + spin_lock_irqsave(&table->cache_lock, flags); + while (!list_empty(&table->stripe_cache)) { + rbio = list_entry(table->stripe_cache.next, + struct btrfs_raid_bio, + stripe_cache); + __remove_rbio_from_cache(rbio); + } + spin_unlock_irqrestore(&table->cache_lock, flags); +} + +/* + * remove all cached entries and free the hash table + * used by unmount + */ +void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info) +{ + if (!info->stripe_hash_table) + return; + btrfs_clear_rbio_cache(info); + kvfree(info->stripe_hash_table); + info->stripe_hash_table = NULL; +} + +/* + * insert an rbio into the stripe cache. It + * must have already been prepared by calling + * cache_rbio_pages + * + * If this rbio was already cached, it gets + * moved to the front of the lru. + * + * If the size of the rbio cache is too big, we + * prune an item. + */ +static void cache_rbio(struct btrfs_raid_bio *rbio) +{ + struct btrfs_stripe_hash_table *table; + unsigned long flags; + + if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags)) + return; + + table = rbio->bioc->fs_info->stripe_hash_table; + + spin_lock_irqsave(&table->cache_lock, flags); + spin_lock(&rbio->bio_list_lock); + + /* bump our ref if we were not in the list before */ + if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags)) + refcount_inc(&rbio->refs); + + if (!list_empty(&rbio->stripe_cache)){ + list_move(&rbio->stripe_cache, &table->stripe_cache); + } else { + list_add(&rbio->stripe_cache, &table->stripe_cache); + table->cache_size += 1; + } + + spin_unlock(&rbio->bio_list_lock); + + if (table->cache_size > RBIO_CACHE_SIZE) { + struct btrfs_raid_bio *found; + + found = list_entry(table->stripe_cache.prev, + struct btrfs_raid_bio, + stripe_cache); + + if (found != rbio) + __remove_rbio_from_cache(found); + } + + spin_unlock_irqrestore(&table->cache_lock, flags); +} + +/* + * helper function to run the xor_blocks api. It is only + * able to do MAX_XOR_BLOCKS at a time, so we need to + * loop through. + */ +static void run_xor(void **pages, int src_cnt, ssize_t len) +{ + int src_off = 0; + int xor_src_cnt = 0; + void *dest = pages[src_cnt]; + + while(src_cnt > 0) { + xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS); + xor_blocks(xor_src_cnt, len, dest, pages + src_off); + + src_cnt -= xor_src_cnt; + src_off += xor_src_cnt; + } +} + +/* + * Returns true if the bio list inside this rbio covers an entire stripe (no + * rmw required). + */ +static int rbio_is_full(struct btrfs_raid_bio *rbio) +{ + unsigned long flags; + unsigned long size = rbio->bio_list_bytes; + int ret = 1; + + spin_lock_irqsave(&rbio->bio_list_lock, flags); + if (size != rbio->nr_data * BTRFS_STRIPE_LEN) + ret = 0; + BUG_ON(size > rbio->nr_data * BTRFS_STRIPE_LEN); + spin_unlock_irqrestore(&rbio->bio_list_lock, flags); + + return ret; +} + +/* + * returns 1 if it is safe to merge two rbios together. + * The merging is safe if the two rbios correspond to + * the same stripe and if they are both going in the same + * direction (read vs write), and if neither one is + * locked for final IO + * + * The caller is responsible for locking such that + * rmw_locked is safe to test + */ +static int rbio_can_merge(struct btrfs_raid_bio *last, + struct btrfs_raid_bio *cur) +{ + if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) || + test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) + return 0; + + /* + * we can't merge with cached rbios, since the + * idea is that when we merge the destination + * rbio is going to run our IO for us. We can + * steal from cached rbios though, other functions + * handle that. + */ + if (test_bit(RBIO_CACHE_BIT, &last->flags) || + test_bit(RBIO_CACHE_BIT, &cur->flags)) + return 0; + + if (last->bioc->raid_map[0] != cur->bioc->raid_map[0]) + return 0; + + /* we can't merge with different operations */ + if (last->operation != cur->operation) + return 0; + /* + * We've need read the full stripe from the drive. + * check and repair the parity and write the new results. + * + * We're not allowed to add any new bios to the + * bio list here, anyone else that wants to + * change this stripe needs to do their own rmw. + */ + if (last->operation == BTRFS_RBIO_PARITY_SCRUB) + return 0; + + if (last->operation == BTRFS_RBIO_REBUILD_MISSING) + return 0; + + if (last->operation == BTRFS_RBIO_READ_REBUILD) { + int fa = last->faila; + int fb = last->failb; + int cur_fa = cur->faila; + int cur_fb = cur->failb; + + if (last->faila >= last->failb) { + fa = last->failb; + fb = last->faila; + } + + if (cur->faila >= cur->failb) { + cur_fa = cur->failb; + cur_fb = cur->faila; + } + + if (fa != cur_fa || fb != cur_fb) + return 0; + } + return 1; +} + +static unsigned int rbio_stripe_sector_index(const struct btrfs_raid_bio *rbio, + unsigned int stripe_nr, + unsigned int sector_nr) +{ + ASSERT(stripe_nr < rbio->real_stripes); + ASSERT(sector_nr < rbio->stripe_nsectors); + + return stripe_nr * rbio->stripe_nsectors + sector_nr; +} + +/* Return a sector from rbio->stripe_sectors, not from the bio list */ +static struct sector_ptr *rbio_stripe_sector(const struct btrfs_raid_bio *rbio, + unsigned int stripe_nr, + unsigned int sector_nr) +{ + return &rbio->stripe_sectors[rbio_stripe_sector_index(rbio, stripe_nr, + sector_nr)]; +} + +/* Grab a sector inside P stripe */ +static struct sector_ptr *rbio_pstripe_sector(const struct btrfs_raid_bio *rbio, + unsigned int sector_nr) +{ + return rbio_stripe_sector(rbio, rbio->nr_data, sector_nr); +} + +/* Grab a sector inside Q stripe, return NULL if not RAID6 */ +static struct sector_ptr *rbio_qstripe_sector(const struct btrfs_raid_bio *rbio, + unsigned int sector_nr) +{ + if (rbio->nr_data + 1 == rbio->real_stripes) + return NULL; + return rbio_stripe_sector(rbio, rbio->nr_data + 1, sector_nr); +} + +/* + * The first stripe in the table for a logical address + * has the lock. rbios are added in one of three ways: + * + * 1) Nobody has the stripe locked yet. The rbio is given + * the lock and 0 is returned. The caller must start the IO + * themselves. + * + * 2) Someone has the stripe locked, but we're able to merge + * with the lock owner. The rbio is freed and the IO will + * start automatically along with the existing rbio. 1 is returned. + * + * 3) Someone has the stripe locked, but we're not able to merge. + * The rbio is added to the lock owner's plug list, or merged into + * an rbio already on the plug list. When the lock owner unlocks, + * the next rbio on the list is run and the IO is started automatically. + * 1 is returned + * + * If we return 0, the caller still owns the rbio and must continue with + * IO submission. If we return 1, the caller must assume the rbio has + * already been freed. + */ +static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio) +{ + struct btrfs_stripe_hash *h; + struct btrfs_raid_bio *cur; + struct btrfs_raid_bio *pending; + unsigned long flags; + struct btrfs_raid_bio *freeit = NULL; + struct btrfs_raid_bio *cache_drop = NULL; + int ret = 0; + + h = rbio->bioc->fs_info->stripe_hash_table->table + rbio_bucket(rbio); + + spin_lock_irqsave(&h->lock, flags); + list_for_each_entry(cur, &h->hash_list, hash_list) { + if (cur->bioc->raid_map[0] != rbio->bioc->raid_map[0]) + continue; + + spin_lock(&cur->bio_list_lock); + + /* Can we steal this cached rbio's pages? */ + if (bio_list_empty(&cur->bio_list) && + list_empty(&cur->plug_list) && + test_bit(RBIO_CACHE_BIT, &cur->flags) && + !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) { + list_del_init(&cur->hash_list); + refcount_dec(&cur->refs); + + steal_rbio(cur, rbio); + cache_drop = cur; + spin_unlock(&cur->bio_list_lock); + + goto lockit; + } + + /* Can we merge into the lock owner? */ + if (rbio_can_merge(cur, rbio)) { + merge_rbio(cur, rbio); + spin_unlock(&cur->bio_list_lock); + freeit = rbio; + ret = 1; + goto out; + } + + + /* + * We couldn't merge with the running rbio, see if we can merge + * with the pending ones. We don't have to check for rmw_locked + * because there is no way they are inside finish_rmw right now + */ + list_for_each_entry(pending, &cur->plug_list, plug_list) { + if (rbio_can_merge(pending, rbio)) { + merge_rbio(pending, rbio); + spin_unlock(&cur->bio_list_lock); + freeit = rbio; + ret = 1; + goto out; + } + } + + /* + * No merging, put us on the tail of the plug list, our rbio + * will be started with the currently running rbio unlocks + */ + list_add_tail(&rbio->plug_list, &cur->plug_list); + spin_unlock(&cur->bio_list_lock); + ret = 1; + goto out; + } +lockit: + refcount_inc(&rbio->refs); + list_add(&rbio->hash_list, &h->hash_list); +out: + spin_unlock_irqrestore(&h->lock, flags); + if (cache_drop) + remove_rbio_from_cache(cache_drop); + if (freeit) + __free_raid_bio(freeit); + return ret; +} + +/* + * called as rmw or parity rebuild is completed. If the plug list has more + * rbios waiting for this stripe, the next one on the list will be started + */ +static noinline void unlock_stripe(struct btrfs_raid_bio *rbio) +{ + int bucket; + struct btrfs_stripe_hash *h; + unsigned long flags; + int keep_cache = 0; + + bucket = rbio_bucket(rbio); + h = rbio->bioc->fs_info->stripe_hash_table->table + bucket; + + if (list_empty(&rbio->plug_list)) + cache_rbio(rbio); + + spin_lock_irqsave(&h->lock, flags); + spin_lock(&rbio->bio_list_lock); + + if (!list_empty(&rbio->hash_list)) { + /* + * if we're still cached and there is no other IO + * to perform, just leave this rbio here for others + * to steal from later + */ + if (list_empty(&rbio->plug_list) && + test_bit(RBIO_CACHE_BIT, &rbio->flags)) { + keep_cache = 1; + clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); + BUG_ON(!bio_list_empty(&rbio->bio_list)); + goto done; + } + + list_del_init(&rbio->hash_list); + refcount_dec(&rbio->refs); + + /* + * we use the plug list to hold all the rbios + * waiting for the chance to lock this stripe. + * hand the lock over to one of them. + */ + if (!list_empty(&rbio->plug_list)) { + struct btrfs_raid_bio *next; + struct list_head *head = rbio->plug_list.next; + + next = list_entry(head, struct btrfs_raid_bio, + plug_list); + + list_del_init(&rbio->plug_list); + + list_add(&next->hash_list, &h->hash_list); + refcount_inc(&next->refs); + spin_unlock(&rbio->bio_list_lock); + spin_unlock_irqrestore(&h->lock, flags); + + if (next->operation == BTRFS_RBIO_READ_REBUILD) + start_async_work(next, read_rebuild_work); + else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) { + steal_rbio(rbio, next); + start_async_work(next, read_rebuild_work); + } else if (next->operation == BTRFS_RBIO_WRITE) { + steal_rbio(rbio, next); + start_async_work(next, rmw_work); + } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) { + steal_rbio(rbio, next); + start_async_work(next, scrub_parity_work); + } + + goto done_nolock; + } + } +done: + spin_unlock(&rbio->bio_list_lock); + spin_unlock_irqrestore(&h->lock, flags); + +done_nolock: + if (!keep_cache) + remove_rbio_from_cache(rbio); +} + +static void __free_raid_bio(struct btrfs_raid_bio *rbio) +{ + int i; + + if (!refcount_dec_and_test(&rbio->refs)) + return; + + WARN_ON(!list_empty(&rbio->stripe_cache)); + WARN_ON(!list_empty(&rbio->hash_list)); + WARN_ON(!bio_list_empty(&rbio->bio_list)); + + for (i = 0; i < rbio->nr_pages; i++) { + if (rbio->stripe_pages[i]) { + __free_page(rbio->stripe_pages[i]); + rbio->stripe_pages[i] = NULL; + } + } + + btrfs_put_bioc(rbio->bioc); + kfree(rbio); +} + +static void rbio_endio_bio_list(struct bio *cur, blk_status_t err) +{ + struct bio *next; + + while (cur) { + next = cur->bi_next; + cur->bi_next = NULL; + cur->bi_status = err; + bio_endio(cur); + cur = next; + } +} + +/* + * this frees the rbio and runs through all the bios in the + * bio_list and calls end_io on them + */ +static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err) +{ + struct bio *cur = bio_list_get(&rbio->bio_list); + struct bio *extra; + + /* + * Clear the data bitmap, as the rbio may be cached for later usage. + * do this before before unlock_stripe() so there will be no new bio + * for this bio. + */ + bitmap_clear(&rbio->dbitmap, 0, rbio->stripe_nsectors); + + /* + * At this moment, rbio->bio_list is empty, however since rbio does not + * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the + * hash list, rbio may be merged with others so that rbio->bio_list + * becomes non-empty. + * Once unlock_stripe() is done, rbio->bio_list will not be updated any + * more and we can call bio_endio() on all queued bios. + */ + unlock_stripe(rbio); + extra = bio_list_get(&rbio->bio_list); + __free_raid_bio(rbio); + + rbio_endio_bio_list(cur, err); + if (extra) + rbio_endio_bio_list(extra, err); +} + +/* + * end io function used by finish_rmw. When we finally + * get here, we've written a full stripe + */ +static void raid_write_end_io(struct bio *bio) +{ + struct btrfs_raid_bio *rbio = bio->bi_private; + blk_status_t err = bio->bi_status; + int max_errors; + + if (err) + fail_bio_stripe(rbio, bio); + + bio_put(bio); + + if (!atomic_dec_and_test(&rbio->stripes_pending)) + return; + + err = BLK_STS_OK; + + /* OK, we have read all the stripes we need to. */ + max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ? + 0 : rbio->bioc->max_errors; + if (atomic_read(&rbio->error) > max_errors) + err = BLK_STS_IOERR; + + rbio_orig_end_io(rbio, err); +} + +/** + * Get a sector pointer specified by its @stripe_nr and @sector_nr + * + * @rbio: The raid bio + * @stripe_nr: Stripe number, valid range [0, real_stripe) + * @sector_nr: Sector number inside the stripe, + * valid range [0, stripe_nsectors) + * @bio_list_only: Whether to use sectors inside the bio list only. + * + * The read/modify/write code wants to reuse the original bio page as much + * as possible, and only use stripe_sectors as fallback. + */ +static struct sector_ptr *sector_in_rbio(struct btrfs_raid_bio *rbio, + int stripe_nr, int sector_nr, + bool bio_list_only) +{ + struct sector_ptr *sector; + int index; + + ASSERT(stripe_nr >= 0 && stripe_nr < rbio->real_stripes); + ASSERT(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors); + + index = stripe_nr * rbio->stripe_nsectors + sector_nr; + ASSERT(index >= 0 && index < rbio->nr_sectors); + + spin_lock_irq(&rbio->bio_list_lock); + sector = &rbio->bio_sectors[index]; + if (sector->page || bio_list_only) { + /* Don't return sector without a valid page pointer */ + if (!sector->page) + sector = NULL; + spin_unlock_irq(&rbio->bio_list_lock); + return sector; + } + spin_unlock_irq(&rbio->bio_list_lock); + + return &rbio->stripe_sectors[index]; +} + +/* + * allocation and initial setup for the btrfs_raid_bio. Not + * this does not allocate any pages for rbio->pages. + */ +static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info, + struct btrfs_io_context *bioc) +{ + const unsigned int real_stripes = bioc->num_stripes - bioc->num_tgtdevs; + const unsigned int stripe_npages = BTRFS_STRIPE_LEN >> PAGE_SHIFT; + const unsigned int num_pages = stripe_npages * real_stripes; + const unsigned int stripe_nsectors = + BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits; + const unsigned int num_sectors = stripe_nsectors * real_stripes; + struct btrfs_raid_bio *rbio; + void *p; + + /* PAGE_SIZE must also be aligned to sectorsize for subpage support */ + ASSERT(IS_ALIGNED(PAGE_SIZE, fs_info->sectorsize)); + /* + * Our current stripe len should be fixed to 64k thus stripe_nsectors + * (at most 16) should be no larger than BITS_PER_LONG. + */ + ASSERT(stripe_nsectors <= BITS_PER_LONG); + + rbio = kzalloc(sizeof(*rbio) + + sizeof(*rbio->stripe_pages) * num_pages + + sizeof(*rbio->bio_sectors) * num_sectors + + sizeof(*rbio->stripe_sectors) * num_sectors + + sizeof(*rbio->finish_pointers) * real_stripes, + GFP_NOFS); + if (!rbio) + return ERR_PTR(-ENOMEM); + + bio_list_init(&rbio->bio_list); + INIT_LIST_HEAD(&rbio->plug_list); + spin_lock_init(&rbio->bio_list_lock); + INIT_LIST_HEAD(&rbio->stripe_cache); + INIT_LIST_HEAD(&rbio->hash_list); + btrfs_get_bioc(bioc); + rbio->bioc = bioc; + rbio->nr_pages = num_pages; + rbio->nr_sectors = num_sectors; + rbio->real_stripes = real_stripes; + rbio->stripe_npages = stripe_npages; + rbio->stripe_nsectors = stripe_nsectors; + rbio->faila = -1; + rbio->failb = -1; + refcount_set(&rbio->refs, 1); + atomic_set(&rbio->error, 0); + atomic_set(&rbio->stripes_pending, 0); + + /* + * The stripe_pages, bio_sectors, etc arrays point to the extra memory + * we allocated past the end of the rbio. + */ + p = rbio + 1; +#define CONSUME_ALLOC(ptr, count) do { \ + ptr = p; \ + p = (unsigned char *)p + sizeof(*(ptr)) * (count); \ + } while (0) + CONSUME_ALLOC(rbio->stripe_pages, num_pages); + CONSUME_ALLOC(rbio->bio_sectors, num_sectors); + CONSUME_ALLOC(rbio->stripe_sectors, num_sectors); + CONSUME_ALLOC(rbio->finish_pointers, real_stripes); +#undef CONSUME_ALLOC + + ASSERT(btrfs_nr_parity_stripes(bioc->map_type)); + rbio->nr_data = real_stripes - btrfs_nr_parity_stripes(bioc->map_type); + + return rbio; +} + +/* allocate pages for all the stripes in the bio, including parity */ +static int alloc_rbio_pages(struct btrfs_raid_bio *rbio) +{ + int ret; + + ret = btrfs_alloc_page_array(rbio->nr_pages, rbio->stripe_pages); + if (ret < 0) + return ret; + /* Mapping all sectors */ + index_stripe_sectors(rbio); + return 0; +} + +/* only allocate pages for p/q stripes */ +static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio) +{ + const int data_pages = rbio->nr_data * rbio->stripe_npages; + int ret; + + ret = btrfs_alloc_page_array(rbio->nr_pages - data_pages, + rbio->stripe_pages + data_pages); + if (ret < 0) + return ret; + + index_stripe_sectors(rbio); + return 0; +} + +/* + * Add a single sector @sector into our list of bios for IO. + * + * Return 0 if everything went well. + * Return <0 for error. + */ +static int rbio_add_io_sector(struct btrfs_raid_bio *rbio, + struct bio_list *bio_list, + struct sector_ptr *sector, + unsigned int stripe_nr, + unsigned int sector_nr, + enum req_op op) +{ + const u32 sectorsize = rbio->bioc->fs_info->sectorsize; + struct bio *last = bio_list->tail; + int ret; + struct bio *bio; + struct btrfs_io_stripe *stripe; + u64 disk_start; + + /* + * Note: here stripe_nr has taken device replace into consideration, + * thus it can be larger than rbio->real_stripe. + * So here we check against bioc->num_stripes, not rbio->real_stripes. + */ + ASSERT(stripe_nr >= 0 && stripe_nr < rbio->bioc->num_stripes); + ASSERT(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors); + ASSERT(sector->page); + + stripe = &rbio->bioc->stripes[stripe_nr]; + disk_start = stripe->physical + sector_nr * sectorsize; + + /* if the device is missing, just fail this stripe */ + if (!stripe->dev->bdev) + return fail_rbio_index(rbio, stripe_nr); + + /* see if we can add this page onto our existing bio */ + if (last) { + u64 last_end = last->bi_iter.bi_sector << 9; + last_end += last->bi_iter.bi_size; + + /* + * we can't merge these if they are from different + * devices or if they are not contiguous + */ + if (last_end == disk_start && !last->bi_status && + last->bi_bdev == stripe->dev->bdev) { + ret = bio_add_page(last, sector->page, sectorsize, + sector->pgoff); + if (ret == sectorsize) + return 0; + } + } + + /* put a new bio on the list */ + bio = bio_alloc(stripe->dev->bdev, + max(BTRFS_STRIPE_LEN >> PAGE_SHIFT, 1), + op, GFP_NOFS); + bio->bi_iter.bi_sector = disk_start >> 9; + bio->bi_private = rbio; + + bio_add_page(bio, sector->page, sectorsize, sector->pgoff); + bio_list_add(bio_list, bio); + return 0; +} + +/* + * while we're doing the read/modify/write cycle, we could + * have errors in reading pages off the disk. This checks + * for errors and if we're not able to read the page it'll + * trigger parity reconstruction. The rmw will be finished + * after we've reconstructed the failed stripes + */ +static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio) +{ + if (rbio->faila >= 0 || rbio->failb >= 0) { + BUG_ON(rbio->faila == rbio->real_stripes - 1); + __raid56_parity_recover(rbio); + } else { + finish_rmw(rbio); + } +} + +static void index_one_bio(struct btrfs_raid_bio *rbio, struct bio *bio) +{ + const u32 sectorsize = rbio->bioc->fs_info->sectorsize; + struct bio_vec bvec; + struct bvec_iter iter; + u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) - + rbio->bioc->raid_map[0]; + + bio_for_each_segment(bvec, bio, iter) { + u32 bvec_offset; + + for (bvec_offset = 0; bvec_offset < bvec.bv_len; + bvec_offset += sectorsize, offset += sectorsize) { + int index = offset / sectorsize; + struct sector_ptr *sector = &rbio->bio_sectors[index]; + + sector->page = bvec.bv_page; + sector->pgoff = bvec.bv_offset + bvec_offset; + ASSERT(sector->pgoff < PAGE_SIZE); + } + } +} + +/* + * helper function to walk our bio list and populate the bio_pages array with + * the result. This seems expensive, but it is faster than constantly + * searching through the bio list as we setup the IO in finish_rmw or stripe + * reconstruction. + * + * This must be called before you trust the answers from page_in_rbio + */ +static void index_rbio_pages(struct btrfs_raid_bio *rbio) +{ + struct bio *bio; + + spin_lock_irq(&rbio->bio_list_lock); + bio_list_for_each(bio, &rbio->bio_list) + index_one_bio(rbio, bio); + + spin_unlock_irq(&rbio->bio_list_lock); +} + +static void bio_get_trace_info(struct btrfs_raid_bio *rbio, struct bio *bio, + struct raid56_bio_trace_info *trace_info) +{ + const struct btrfs_io_context *bioc = rbio->bioc; + int i; + + ASSERT(bioc); + + /* We rely on bio->bi_bdev to find the stripe number. */ + if (!bio->bi_bdev) + goto not_found; + + for (i = 0; i < bioc->num_stripes; i++) { + if (bio->bi_bdev != bioc->stripes[i].dev->bdev) + continue; + trace_info->stripe_nr = i; + trace_info->devid = bioc->stripes[i].dev->devid; + trace_info->offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) - + bioc->stripes[i].physical; + return; + } + +not_found: + trace_info->devid = -1; + trace_info->offset = -1; + trace_info->stripe_nr = -1; +} + +/* + * this is called from one of two situations. We either + * have a full stripe from the higher layers, or we've read all + * the missing bits off disk. + * + * This will calculate the parity and then send down any + * changed blocks. + */ +static noinline void finish_rmw(struct btrfs_raid_bio *rbio) +{ + struct btrfs_io_context *bioc = rbio->bioc; + const u32 sectorsize = bioc->fs_info->sectorsize; + void **pointers = rbio->finish_pointers; + int nr_data = rbio->nr_data; + /* The total sector number inside the full stripe. */ + int total_sector_nr; + int stripe; + /* Sector number inside a stripe. */ + int sectornr; + bool has_qstripe; + struct bio_list bio_list; + struct bio *bio; + int ret; + + bio_list_init(&bio_list); + + if (rbio->real_stripes - rbio->nr_data == 1) + has_qstripe = false; + else if (rbio->real_stripes - rbio->nr_data == 2) + has_qstripe = true; + else + BUG(); + + /* We should have at least one data sector. */ + ASSERT(bitmap_weight(&rbio->dbitmap, rbio->stripe_nsectors)); + + /* at this point we either have a full stripe, + * or we've read the full stripe from the drive. + * recalculate the parity and write the new results. + * + * We're not allowed to add any new bios to the + * bio list here, anyone else that wants to + * change this stripe needs to do their own rmw. + */ + spin_lock_irq(&rbio->bio_list_lock); + set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); + spin_unlock_irq(&rbio->bio_list_lock); + + atomic_set(&rbio->error, 0); + + /* + * now that we've set rmw_locked, run through the + * bio list one last time and map the page pointers + * + * We don't cache full rbios because we're assuming + * the higher layers are unlikely to use this area of + * the disk again soon. If they do use it again, + * hopefully they will send another full bio. + */ + index_rbio_pages(rbio); + if (!rbio_is_full(rbio)) + cache_rbio_pages(rbio); + else + clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); + + for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) { + struct sector_ptr *sector; + + /* First collect one sector from each data stripe */ + for (stripe = 0; stripe < nr_data; stripe++) { + sector = sector_in_rbio(rbio, stripe, sectornr, 0); + pointers[stripe] = kmap_local_page(sector->page) + + sector->pgoff; + } + + /* Then add the parity stripe */ + sector = rbio_pstripe_sector(rbio, sectornr); + sector->uptodate = 1; + pointers[stripe++] = kmap_local_page(sector->page) + sector->pgoff; + + if (has_qstripe) { + /* + * RAID6, add the qstripe and call the library function + * to fill in our p/q + */ + sector = rbio_qstripe_sector(rbio, sectornr); + sector->uptodate = 1; + pointers[stripe++] = kmap_local_page(sector->page) + + sector->pgoff; + + raid6_call.gen_syndrome(rbio->real_stripes, sectorsize, + pointers); + } else { + /* raid5 */ + memcpy(pointers[nr_data], pointers[0], sectorsize); + run_xor(pointers + 1, nr_data - 1, sectorsize); + } + for (stripe = stripe - 1; stripe >= 0; stripe--) + kunmap_local(pointers[stripe]); + } + + /* + * Start writing. Make bios for everything from the higher layers (the + * bio_list in our rbio) and our P/Q. Ignore everything else. + */ + for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors; + total_sector_nr++) { + struct sector_ptr *sector; + + stripe = total_sector_nr / rbio->stripe_nsectors; + sectornr = total_sector_nr % rbio->stripe_nsectors; + + /* This vertical stripe has no data, skip it. */ + if (!test_bit(sectornr, &rbio->dbitmap)) + continue; + + if (stripe < rbio->nr_data) { + sector = sector_in_rbio(rbio, stripe, sectornr, 1); + if (!sector) + continue; + } else { + sector = rbio_stripe_sector(rbio, stripe, sectornr); + } + + ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe, + sectornr, REQ_OP_WRITE); + if (ret) + goto cleanup; + } + + if (likely(!bioc->num_tgtdevs)) + goto write_data; + + for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors; + total_sector_nr++) { + struct sector_ptr *sector; + + stripe = total_sector_nr / rbio->stripe_nsectors; + sectornr = total_sector_nr % rbio->stripe_nsectors; + + if (!bioc->tgtdev_map[stripe]) { + /* + * We can skip the whole stripe completely, note + * total_sector_nr will be increased by one anyway. + */ + ASSERT(sectornr == 0); + total_sector_nr += rbio->stripe_nsectors - 1; + continue; + } + + /* This vertical stripe has no data, skip it. */ + if (!test_bit(sectornr, &rbio->dbitmap)) + continue; + + if (stripe < rbio->nr_data) { + sector = sector_in_rbio(rbio, stripe, sectornr, 1); + if (!sector) + continue; + } else { + sector = rbio_stripe_sector(rbio, stripe, sectornr); + } + + ret = rbio_add_io_sector(rbio, &bio_list, sector, + rbio->bioc->tgtdev_map[stripe], + sectornr, REQ_OP_WRITE); + if (ret) + goto cleanup; + } + +write_data: + atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list)); + BUG_ON(atomic_read(&rbio->stripes_pending) == 0); + + while ((bio = bio_list_pop(&bio_list))) { + bio->bi_end_io = raid_write_end_io; + + if (trace_raid56_write_stripe_enabled()) { + struct raid56_bio_trace_info trace_info = { 0 }; + + bio_get_trace_info(rbio, bio, &trace_info); + trace_raid56_write_stripe(rbio, bio, &trace_info); + } + submit_bio(bio); + } + return; + +cleanup: + rbio_orig_end_io(rbio, BLK_STS_IOERR); + + while ((bio = bio_list_pop(&bio_list))) + bio_put(bio); +} + +/* + * helper to find the stripe number for a given bio. Used to figure out which + * stripe has failed. This expects the bio to correspond to a physical disk, + * so it looks up based on physical sector numbers. + */ +static int find_bio_stripe(struct btrfs_raid_bio *rbio, + struct bio *bio) +{ + u64 physical = bio->bi_iter.bi_sector; + int i; + struct btrfs_io_stripe *stripe; + + physical <<= 9; + + for (i = 0; i < rbio->bioc->num_stripes; i++) { + stripe = &rbio->bioc->stripes[i]; + if (in_range(physical, stripe->physical, BTRFS_STRIPE_LEN) && + stripe->dev->bdev && bio->bi_bdev == stripe->dev->bdev) { + return i; + } + } + return -1; +} + +/* + * helper to find the stripe number for a given + * bio (before mapping). Used to figure out which stripe has + * failed. This looks up based on logical block numbers. + */ +static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio, + struct bio *bio) +{ + u64 logical = bio->bi_iter.bi_sector << 9; + int i; + + for (i = 0; i < rbio->nr_data; i++) { + u64 stripe_start = rbio->bioc->raid_map[i]; + + if (in_range(logical, stripe_start, BTRFS_STRIPE_LEN)) + return i; + } + return -1; +} + +/* + * returns -EIO if we had too many failures + */ +static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed) +{ + unsigned long flags; + int ret = 0; + + spin_lock_irqsave(&rbio->bio_list_lock, flags); + + /* we already know this stripe is bad, move on */ + if (rbio->faila == failed || rbio->failb == failed) + goto out; + + if (rbio->faila == -1) { + /* first failure on this rbio */ + rbio->faila = failed; + atomic_inc(&rbio->error); + } else if (rbio->failb == -1) { + /* second failure on this rbio */ + rbio->failb = failed; + atomic_inc(&rbio->error); + } else { + ret = -EIO; + } +out: + spin_unlock_irqrestore(&rbio->bio_list_lock, flags); + + return ret; +} + +/* + * helper to fail a stripe based on a physical disk + * bio. + */ +static int fail_bio_stripe(struct btrfs_raid_bio *rbio, + struct bio *bio) +{ + int failed = find_bio_stripe(rbio, bio); + + if (failed < 0) + return -EIO; + + return fail_rbio_index(rbio, failed); +} + +/* + * For subpage case, we can no longer set page Uptodate directly for + * stripe_pages[], thus we need to locate the sector. + */ +static struct sector_ptr *find_stripe_sector(struct btrfs_raid_bio *rbio, + struct page *page, + unsigned int pgoff) +{ + int i; + + for (i = 0; i < rbio->nr_sectors; i++) { + struct sector_ptr *sector = &rbio->stripe_sectors[i]; + + if (sector->page == page && sector->pgoff == pgoff) + return sector; + } + return NULL; +} + +/* + * this sets each page in the bio uptodate. It should only be used on private + * rbio pages, nothing that comes in from the higher layers + */ +static void set_bio_pages_uptodate(struct btrfs_raid_bio *rbio, struct bio *bio) +{ + const u32 sectorsize = rbio->bioc->fs_info->sectorsize; + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + + ASSERT(!bio_flagged(bio, BIO_CLONED)); + + bio_for_each_segment_all(bvec, bio, iter_all) { + struct sector_ptr *sector; + int pgoff; + + for (pgoff = bvec->bv_offset; pgoff - bvec->bv_offset < bvec->bv_len; + pgoff += sectorsize) { + sector = find_stripe_sector(rbio, bvec->bv_page, pgoff); + ASSERT(sector); + if (sector) + sector->uptodate = 1; + } + } +} + +static void raid56_bio_end_io(struct bio *bio) +{ + struct btrfs_raid_bio *rbio = bio->bi_private; + + if (bio->bi_status) + fail_bio_stripe(rbio, bio); + else + set_bio_pages_uptodate(rbio, bio); + + bio_put(bio); + + if (atomic_dec_and_test(&rbio->stripes_pending)) + queue_work(rbio->bioc->fs_info->endio_raid56_workers, + &rbio->end_io_work); +} + +/* + * End io handler for the read phase of the RMW cycle. All the bios here are + * physical stripe bios we've read from the disk so we can recalculate the + * parity of the stripe. + * + * This will usually kick off finish_rmw once all the bios are read in, but it + * may trigger parity reconstruction if we had any errors along the way + */ +static void raid56_rmw_end_io_work(struct work_struct *work) +{ + struct btrfs_raid_bio *rbio = + container_of(work, struct btrfs_raid_bio, end_io_work); + + if (atomic_read(&rbio->error) > rbio->bioc->max_errors) { + rbio_orig_end_io(rbio, BLK_STS_IOERR); + return; + } + + /* + * This will normally call finish_rmw to start our write but if there + * are any failed stripes we'll reconstruct from parity first. + */ + validate_rbio_for_rmw(rbio); +} + +/* + * the stripe must be locked by the caller. It will + * unlock after all the writes are done + */ +static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio) +{ + int bios_to_read = 0; + struct bio_list bio_list; + const int nr_data_sectors = rbio->stripe_nsectors * rbio->nr_data; + int ret; + int total_sector_nr; + struct bio *bio; + + bio_list_init(&bio_list); + + ret = alloc_rbio_pages(rbio); + if (ret) + goto cleanup; + + index_rbio_pages(rbio); + + atomic_set(&rbio->error, 0); + /* Build a list of bios to read all the missing data sectors. */ + for (total_sector_nr = 0; total_sector_nr < nr_data_sectors; + total_sector_nr++) { + struct sector_ptr *sector; + int stripe = total_sector_nr / rbio->stripe_nsectors; + int sectornr = total_sector_nr % rbio->stripe_nsectors; + + /* + * We want to find all the sectors missing from the rbio and + * read them from the disk. If sector_in_rbio() finds a page + * in the bio list we don't need to read it off the stripe. + */ + sector = sector_in_rbio(rbio, stripe, sectornr, 1); + if (sector) + continue; + + sector = rbio_stripe_sector(rbio, stripe, sectornr); + /* + * The bio cache may have handed us an uptodate page. If so, + * use it. + */ + if (sector->uptodate) + continue; + + ret = rbio_add_io_sector(rbio, &bio_list, sector, + stripe, sectornr, REQ_OP_READ); + if (ret) + goto cleanup; + } + + bios_to_read = bio_list_size(&bio_list); + if (!bios_to_read) { + /* + * this can happen if others have merged with + * us, it means there is nothing left to read. + * But if there are missing devices it may not be + * safe to do the full stripe write yet. + */ + goto finish; + } + + /* + * The bioc may be freed once we submit the last bio. Make sure not to + * touch it after that. + */ + atomic_set(&rbio->stripes_pending, bios_to_read); + INIT_WORK(&rbio->end_io_work, raid56_rmw_end_io_work); + while ((bio = bio_list_pop(&bio_list))) { + bio->bi_end_io = raid56_bio_end_io; + + if (trace_raid56_read_partial_enabled()) { + struct raid56_bio_trace_info trace_info = { 0 }; + + bio_get_trace_info(rbio, bio, &trace_info); + trace_raid56_read_partial(rbio, bio, &trace_info); + } + submit_bio(bio); + } + /* the actual write will happen once the reads are done */ + return 0; + +cleanup: + rbio_orig_end_io(rbio, BLK_STS_IOERR); + + while ((bio = bio_list_pop(&bio_list))) + bio_put(bio); + + return -EIO; + +finish: + validate_rbio_for_rmw(rbio); + return 0; +} + +/* + * if the upper layers pass in a full stripe, we thank them by only allocating + * enough pages to hold the parity, and sending it all down quickly. + */ +static int full_stripe_write(struct btrfs_raid_bio *rbio) +{ + int ret; + + ret = alloc_rbio_parity_pages(rbio); + if (ret) + return ret; + + ret = lock_stripe_add(rbio); + if (ret == 0) + finish_rmw(rbio); + return 0; +} + +/* + * partial stripe writes get handed over to async helpers. + * We're really hoping to merge a few more writes into this + * rbio before calculating new parity + */ +static int partial_stripe_write(struct btrfs_raid_bio *rbio) +{ + int ret; + + ret = lock_stripe_add(rbio); + if (ret == 0) + start_async_work(rbio, rmw_work); + return 0; +} + +/* + * sometimes while we were reading from the drive to + * recalculate parity, enough new bios come into create + * a full stripe. So we do a check here to see if we can + * go directly to finish_rmw + */ +static int __raid56_parity_write(struct btrfs_raid_bio *rbio) +{ + /* head off into rmw land if we don't have a full stripe */ + if (!rbio_is_full(rbio)) + return partial_stripe_write(rbio); + return full_stripe_write(rbio); +} + +/* + * We use plugging call backs to collect full stripes. + * Any time we get a partial stripe write while plugged + * we collect it into a list. When the unplug comes down, + * we sort the list by logical block number and merge + * everything we can into the same rbios + */ +struct btrfs_plug_cb { + struct blk_plug_cb cb; + struct btrfs_fs_info *info; + struct list_head rbio_list; + struct work_struct work; +}; + +/* + * rbios on the plug list are sorted for easier merging. + */ +static int plug_cmp(void *priv, const struct list_head *a, + const struct list_head *b) +{ + const struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio, + plug_list); + const struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio, + plug_list); + u64 a_sector = ra->bio_list.head->bi_iter.bi_sector; + u64 b_sector = rb->bio_list.head->bi_iter.bi_sector; + + if (a_sector < b_sector) + return -1; + if (a_sector > b_sector) + return 1; + return 0; +} + +static void run_plug(struct btrfs_plug_cb *plug) +{ + struct btrfs_raid_bio *cur; + struct btrfs_raid_bio *last = NULL; + + /* + * sort our plug list then try to merge + * everything we can in hopes of creating full + * stripes. + */ + list_sort(NULL, &plug->rbio_list, plug_cmp); + while (!list_empty(&plug->rbio_list)) { + cur = list_entry(plug->rbio_list.next, + struct btrfs_raid_bio, plug_list); + list_del_init(&cur->plug_list); + + if (rbio_is_full(cur)) { + int ret; + + /* we have a full stripe, send it down */ + ret = full_stripe_write(cur); + BUG_ON(ret); + continue; + } + if (last) { + if (rbio_can_merge(last, cur)) { + merge_rbio(last, cur); + __free_raid_bio(cur); + continue; + + } + __raid56_parity_write(last); + } + last = cur; + } + if (last) { + __raid56_parity_write(last); + } + kfree(plug); +} + +/* + * if the unplug comes from schedule, we have to push the + * work off to a helper thread + */ +static void unplug_work(struct work_struct *work) +{ + struct btrfs_plug_cb *plug; + plug = container_of(work, struct btrfs_plug_cb, work); + run_plug(plug); +} + +static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule) +{ + struct btrfs_plug_cb *plug; + plug = container_of(cb, struct btrfs_plug_cb, cb); + + if (from_schedule) { + INIT_WORK(&plug->work, unplug_work); + queue_work(plug->info->rmw_workers, &plug->work); + return; + } + run_plug(plug); +} + +/* Add the original bio into rbio->bio_list, and update rbio::dbitmap. */ +static void rbio_add_bio(struct btrfs_raid_bio *rbio, struct bio *orig_bio) +{ + const struct btrfs_fs_info *fs_info = rbio->bioc->fs_info; + const u64 orig_logical = orig_bio->bi_iter.bi_sector << SECTOR_SHIFT; + const u64 full_stripe_start = rbio->bioc->raid_map[0]; + const u32 orig_len = orig_bio->bi_iter.bi_size; + const u32 sectorsize = fs_info->sectorsize; + u64 cur_logical; + + ASSERT(orig_logical >= full_stripe_start && + orig_logical + orig_len <= full_stripe_start + + rbio->nr_data * BTRFS_STRIPE_LEN); + + bio_list_add(&rbio->bio_list, orig_bio); + rbio->bio_list_bytes += orig_bio->bi_iter.bi_size; + + /* Update the dbitmap. */ + for (cur_logical = orig_logical; cur_logical < orig_logical + orig_len; + cur_logical += sectorsize) { + int bit = ((u32)(cur_logical - full_stripe_start) >> + fs_info->sectorsize_bits) % rbio->stripe_nsectors; + + set_bit(bit, &rbio->dbitmap); + } +} + +/* + * our main entry point for writes from the rest of the FS. + */ +void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc) +{ + struct btrfs_fs_info *fs_info = bioc->fs_info; + struct btrfs_raid_bio *rbio; + struct btrfs_plug_cb *plug = NULL; + struct blk_plug_cb *cb; + int ret = 0; + + rbio = alloc_rbio(fs_info, bioc); + if (IS_ERR(rbio)) { + ret = PTR_ERR(rbio); + goto fail; + } + rbio->operation = BTRFS_RBIO_WRITE; + rbio_add_bio(rbio, bio); + + /* + * don't plug on full rbios, just get them out the door + * as quickly as we can + */ + if (rbio_is_full(rbio)) { + ret = full_stripe_write(rbio); + if (ret) { + __free_raid_bio(rbio); + goto fail; + } + return; + } + + cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug)); + if (cb) { + plug = container_of(cb, struct btrfs_plug_cb, cb); + if (!plug->info) { + plug->info = fs_info; + INIT_LIST_HEAD(&plug->rbio_list); + } + list_add_tail(&rbio->plug_list, &plug->rbio_list); + } else { + ret = __raid56_parity_write(rbio); + if (ret) { + __free_raid_bio(rbio); + goto fail; + } + } + + return; + +fail: + bio->bi_status = errno_to_blk_status(ret); + bio_endio(bio); +} + +/* + * all parity reconstruction happens here. We've read in everything + * we can find from the drives and this does the heavy lifting of + * sorting the good from the bad. + */ +static void __raid_recover_end_io(struct btrfs_raid_bio *rbio) +{ + const u32 sectorsize = rbio->bioc->fs_info->sectorsize; + int sectornr, stripe; + void **pointers; + void **unmap_array; + int faila = -1, failb = -1; + blk_status_t err; + int i; + + /* + * This array stores the pointer for each sector, thus it has the extra + * pgoff value added from each sector + */ + pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS); + if (!pointers) { + err = BLK_STS_RESOURCE; + goto cleanup_io; + } + + /* + * Store copy of pointers that does not get reordered during + * reconstruction so that kunmap_local works. + */ + unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS); + if (!unmap_array) { + err = BLK_STS_RESOURCE; + goto cleanup_pointers; + } + + faila = rbio->faila; + failb = rbio->failb; + + if (rbio->operation == BTRFS_RBIO_READ_REBUILD || + rbio->operation == BTRFS_RBIO_REBUILD_MISSING) { + spin_lock_irq(&rbio->bio_list_lock); + set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); + spin_unlock_irq(&rbio->bio_list_lock); + } + + index_rbio_pages(rbio); + + for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) { + struct sector_ptr *sector; + + /* + * Now we just use bitmap to mark the horizontal stripes in + * which we have data when doing parity scrub. + */ + if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB && + !test_bit(sectornr, &rbio->dbitmap)) + continue; + + /* + * Setup our array of pointers with sectors from each stripe + * + * NOTE: store a duplicate array of pointers to preserve the + * pointer order + */ + for (stripe = 0; stripe < rbio->real_stripes; stripe++) { + /* + * If we're rebuilding a read, we have to use + * pages from the bio list + */ + if ((rbio->operation == BTRFS_RBIO_READ_REBUILD || + rbio->operation == BTRFS_RBIO_REBUILD_MISSING) && + (stripe == faila || stripe == failb)) { + sector = sector_in_rbio(rbio, stripe, sectornr, 0); + } else { + sector = rbio_stripe_sector(rbio, stripe, sectornr); + } + ASSERT(sector->page); + pointers[stripe] = kmap_local_page(sector->page) + + sector->pgoff; + unmap_array[stripe] = pointers[stripe]; + } + + /* All raid6 handling here */ + if (rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6) { + /* Single failure, rebuild from parity raid5 style */ + if (failb < 0) { + if (faila == rbio->nr_data) { + /* + * Just the P stripe has failed, without + * a bad data or Q stripe. + * TODO, we should redo the xor here. + */ + err = BLK_STS_IOERR; + goto cleanup; + } + /* + * a single failure in raid6 is rebuilt + * in the pstripe code below + */ + goto pstripe; + } + + /* make sure our ps and qs are in order */ + if (faila > failb) + swap(faila, failb); + + /* if the q stripe is failed, do a pstripe reconstruction + * from the xors. + * If both the q stripe and the P stripe are failed, we're + * here due to a crc mismatch and we can't give them the + * data they want + */ + if (rbio->bioc->raid_map[failb] == RAID6_Q_STRIPE) { + if (rbio->bioc->raid_map[faila] == + RAID5_P_STRIPE) { + err = BLK_STS_IOERR; + goto cleanup; + } + /* + * otherwise we have one bad data stripe and + * a good P stripe. raid5! + */ + goto pstripe; + } + + if (rbio->bioc->raid_map[failb] == RAID5_P_STRIPE) { + raid6_datap_recov(rbio->real_stripes, + sectorsize, faila, pointers); + } else { + raid6_2data_recov(rbio->real_stripes, + sectorsize, faila, failb, + pointers); + } + } else { + void *p; + + /* rebuild from P stripe here (raid5 or raid6) */ + BUG_ON(failb != -1); +pstripe: + /* Copy parity block into failed block to start with */ + memcpy(pointers[faila], pointers[rbio->nr_data], sectorsize); + + /* rearrange the pointer array */ + p = pointers[faila]; + for (stripe = faila; stripe < rbio->nr_data - 1; stripe++) + pointers[stripe] = pointers[stripe + 1]; + pointers[rbio->nr_data - 1] = p; + + /* xor in the rest */ + run_xor(pointers, rbio->nr_data - 1, sectorsize); + } + /* if we're doing this rebuild as part of an rmw, go through + * and set all of our private rbio pages in the + * failed stripes as uptodate. This way finish_rmw will + * know they can be trusted. If this was a read reconstruction, + * other endio functions will fiddle the uptodate bits + */ + if (rbio->operation == BTRFS_RBIO_WRITE) { + for (i = 0; i < rbio->stripe_nsectors; i++) { + if (faila != -1) { + sector = rbio_stripe_sector(rbio, faila, i); + sector->uptodate = 1; + } + if (failb != -1) { + sector = rbio_stripe_sector(rbio, failb, i); + sector->uptodate = 1; + } + } + } + for (stripe = rbio->real_stripes - 1; stripe >= 0; stripe--) + kunmap_local(unmap_array[stripe]); + } + + err = BLK_STS_OK; +cleanup: + kfree(unmap_array); +cleanup_pointers: + kfree(pointers); + +cleanup_io: + /* + * Similar to READ_REBUILD, REBUILD_MISSING at this point also has a + * valid rbio which is consistent with ondisk content, thus such a + * valid rbio can be cached to avoid further disk reads. + */ + if (rbio->operation == BTRFS_RBIO_READ_REBUILD || + rbio->operation == BTRFS_RBIO_REBUILD_MISSING) { + /* + * - In case of two failures, where rbio->failb != -1: + * + * Do not cache this rbio since the above read reconstruction + * (raid6_datap_recov() or raid6_2data_recov()) may have + * changed some content of stripes which are not identical to + * on-disk content any more, otherwise, a later write/recover + * may steal stripe_pages from this rbio and end up with + * corruptions or rebuild failures. + * + * - In case of single failure, where rbio->failb == -1: + * + * Cache this rbio iff the above read reconstruction is + * executed without problems. + */ + if (err == BLK_STS_OK && rbio->failb < 0) + cache_rbio_pages(rbio); + else + clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); + + rbio_orig_end_io(rbio, err); + } else if (err == BLK_STS_OK) { + rbio->faila = -1; + rbio->failb = -1; + + if (rbio->operation == BTRFS_RBIO_WRITE) + finish_rmw(rbio); + else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) + finish_parity_scrub(rbio, 0); + else + BUG(); + } else { + rbio_orig_end_io(rbio, err); + } +} + +/* + * This is called only for stripes we've read from disk to reconstruct the + * parity. + */ +static void raid_recover_end_io_work(struct work_struct *work) +{ + struct btrfs_raid_bio *rbio = + container_of(work, struct btrfs_raid_bio, end_io_work); + + if (atomic_read(&rbio->error) > rbio->bioc->max_errors) + rbio_orig_end_io(rbio, BLK_STS_IOERR); + else + __raid_recover_end_io(rbio); +} + +/* + * reads everything we need off the disk to reconstruct + * the parity. endio handlers trigger final reconstruction + * when the IO is done. + * + * This is used both for reads from the higher layers and for + * parity construction required to finish a rmw cycle. + */ +static int __raid56_parity_recover(struct btrfs_raid_bio *rbio) +{ + int bios_to_read = 0; + struct bio_list bio_list; + int ret; + int total_sector_nr; + struct bio *bio; + + bio_list_init(&bio_list); + + ret = alloc_rbio_pages(rbio); + if (ret) + goto cleanup; + + atomic_set(&rbio->error, 0); + + /* + * Read everything that hasn't failed. However this time we will + * not trust any cached sector. + * As we may read out some stale data but higher layer is not reading + * that stale part. + * + * So here we always re-read everything in recovery path. + */ + for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors; + total_sector_nr++) { + int stripe = total_sector_nr / rbio->stripe_nsectors; + int sectornr = total_sector_nr % rbio->stripe_nsectors; + struct sector_ptr *sector; + + if (rbio->faila == stripe || rbio->failb == stripe) { + atomic_inc(&rbio->error); + /* Skip the current stripe. */ + ASSERT(sectornr == 0); + total_sector_nr += rbio->stripe_nsectors - 1; + continue; + } + sector = rbio_stripe_sector(rbio, stripe, sectornr); + ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe, + sectornr, REQ_OP_READ); + if (ret < 0) + goto cleanup; + } + + bios_to_read = bio_list_size(&bio_list); + if (!bios_to_read) { + /* + * we might have no bios to read just because the pages + * were up to date, or we might have no bios to read because + * the devices were gone. + */ + if (atomic_read(&rbio->error) <= rbio->bioc->max_errors) { + __raid_recover_end_io(rbio); + return 0; + } else { + goto cleanup; + } + } + + /* + * The bioc may be freed once we submit the last bio. Make sure not to + * touch it after that. + */ + atomic_set(&rbio->stripes_pending, bios_to_read); + INIT_WORK(&rbio->end_io_work, raid_recover_end_io_work); + while ((bio = bio_list_pop(&bio_list))) { + bio->bi_end_io = raid56_bio_end_io; + + if (trace_raid56_scrub_read_recover_enabled()) { + struct raid56_bio_trace_info trace_info = { 0 }; + + bio_get_trace_info(rbio, bio, &trace_info); + trace_raid56_scrub_read_recover(rbio, bio, &trace_info); + } + submit_bio(bio); + } + + return 0; + +cleanup: + if (rbio->operation == BTRFS_RBIO_READ_REBUILD || + rbio->operation == BTRFS_RBIO_REBUILD_MISSING) + rbio_orig_end_io(rbio, BLK_STS_IOERR); + + while ((bio = bio_list_pop(&bio_list))) + bio_put(bio); + + return -EIO; +} + +/* + * the main entry point for reads from the higher layers. This + * is really only called when the normal read path had a failure, + * so we assume the bio they send down corresponds to a failed part + * of the drive. + */ +void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc, + int mirror_num) +{ + struct btrfs_fs_info *fs_info = bioc->fs_info; + struct btrfs_raid_bio *rbio; + + rbio = alloc_rbio(fs_info, bioc); + if (IS_ERR(rbio)) { + bio->bi_status = errno_to_blk_status(PTR_ERR(rbio)); + goto out_end_bio; + } + + rbio->operation = BTRFS_RBIO_READ_REBUILD; + rbio_add_bio(rbio, bio); + + rbio->faila = find_logical_bio_stripe(rbio, bio); + if (rbio->faila == -1) { + btrfs_warn(fs_info, +"%s could not find the bad stripe in raid56 so that we cannot recover any more (bio has logical %llu len %llu, bioc has map_type %llu)", + __func__, bio->bi_iter.bi_sector << 9, + (u64)bio->bi_iter.bi_size, bioc->map_type); + __free_raid_bio(rbio); + bio->bi_status = BLK_STS_IOERR; + goto out_end_bio; + } + + /* + * Loop retry: + * for 'mirror == 2', reconstruct from all other stripes. + * for 'mirror_num > 2', select a stripe to fail on every retry. + */ + if (mirror_num > 2) { + /* + * 'mirror == 3' is to fail the p stripe and + * reconstruct from the q stripe. 'mirror > 3' is to + * fail a data stripe and reconstruct from p+q stripe. + */ + rbio->failb = rbio->real_stripes - (mirror_num - 1); + ASSERT(rbio->failb > 0); + if (rbio->failb <= rbio->faila) + rbio->failb--; + } + + if (lock_stripe_add(rbio)) + return; + + /* + * This adds our rbio to the list of rbios that will be handled after + * the current lock owner is done. + */ + __raid56_parity_recover(rbio); + return; + +out_end_bio: + bio_endio(bio); +} + +static void rmw_work(struct work_struct *work) +{ + struct btrfs_raid_bio *rbio; + + rbio = container_of(work, struct btrfs_raid_bio, work); + raid56_rmw_stripe(rbio); +} + +static void read_rebuild_work(struct work_struct *work) +{ + struct btrfs_raid_bio *rbio; + + rbio = container_of(work, struct btrfs_raid_bio, work); + __raid56_parity_recover(rbio); +} + +/* + * The following code is used to scrub/replace the parity stripe + * + * Caller must have already increased bio_counter for getting @bioc. + * + * Note: We need make sure all the pages that add into the scrub/replace + * raid bio are correct and not be changed during the scrub/replace. That + * is those pages just hold metadata or file data with checksum. + */ + +struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio, + struct btrfs_io_context *bioc, + struct btrfs_device *scrub_dev, + unsigned long *dbitmap, int stripe_nsectors) +{ + struct btrfs_fs_info *fs_info = bioc->fs_info; + struct btrfs_raid_bio *rbio; + int i; + + rbio = alloc_rbio(fs_info, bioc); + if (IS_ERR(rbio)) + return NULL; + bio_list_add(&rbio->bio_list, bio); + /* + * This is a special bio which is used to hold the completion handler + * and make the scrub rbio is similar to the other types + */ + ASSERT(!bio->bi_iter.bi_size); + rbio->operation = BTRFS_RBIO_PARITY_SCRUB; + + /* + * After mapping bioc with BTRFS_MAP_WRITE, parities have been sorted + * to the end position, so this search can start from the first parity + * stripe. + */ + for (i = rbio->nr_data; i < rbio->real_stripes; i++) { + if (bioc->stripes[i].dev == scrub_dev) { + rbio->scrubp = i; + break; + } + } + ASSERT(i < rbio->real_stripes); + + bitmap_copy(&rbio->dbitmap, dbitmap, stripe_nsectors); + return rbio; +} + +/* Used for both parity scrub and missing. */ +void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page, + unsigned int pgoff, u64 logical) +{ + const u32 sectorsize = rbio->bioc->fs_info->sectorsize; + int stripe_offset; + int index; + + ASSERT(logical >= rbio->bioc->raid_map[0]); + ASSERT(logical + sectorsize <= rbio->bioc->raid_map[0] + + BTRFS_STRIPE_LEN * rbio->nr_data); + stripe_offset = (int)(logical - rbio->bioc->raid_map[0]); + index = stripe_offset / sectorsize; + rbio->bio_sectors[index].page = page; + rbio->bio_sectors[index].pgoff = pgoff; +} + +/* + * We just scrub the parity that we have correct data on the same horizontal, + * so we needn't allocate all pages for all the stripes. + */ +static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio) +{ + const u32 sectorsize = rbio->bioc->fs_info->sectorsize; + int total_sector_nr; + + for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors; + total_sector_nr++) { + struct page *page; + int sectornr = total_sector_nr % rbio->stripe_nsectors; + int index = (total_sector_nr * sectorsize) >> PAGE_SHIFT; + + if (!test_bit(sectornr, &rbio->dbitmap)) + continue; + if (rbio->stripe_pages[index]) + continue; + page = alloc_page(GFP_NOFS); + if (!page) + return -ENOMEM; + rbio->stripe_pages[index] = page; + } + index_stripe_sectors(rbio); + return 0; +} + +static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, + int need_check) +{ + struct btrfs_io_context *bioc = rbio->bioc; + const u32 sectorsize = bioc->fs_info->sectorsize; + void **pointers = rbio->finish_pointers; + unsigned long *pbitmap = &rbio->finish_pbitmap; + int nr_data = rbio->nr_data; + int stripe; + int sectornr; + bool has_qstripe; + struct sector_ptr p_sector = { 0 }; + struct sector_ptr q_sector = { 0 }; + struct bio_list bio_list; + struct bio *bio; + int is_replace = 0; + int ret; + + bio_list_init(&bio_list); + + if (rbio->real_stripes - rbio->nr_data == 1) + has_qstripe = false; + else if (rbio->real_stripes - rbio->nr_data == 2) + has_qstripe = true; + else + BUG(); + + if (bioc->num_tgtdevs && bioc->tgtdev_map[rbio->scrubp]) { + is_replace = 1; + bitmap_copy(pbitmap, &rbio->dbitmap, rbio->stripe_nsectors); + } + + /* + * Because the higher layers(scrubber) are unlikely to + * use this area of the disk again soon, so don't cache + * it. + */ + clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); + + if (!need_check) + goto writeback; + + p_sector.page = alloc_page(GFP_NOFS); + if (!p_sector.page) + goto cleanup; + p_sector.pgoff = 0; + p_sector.uptodate = 1; + + if (has_qstripe) { + /* RAID6, allocate and map temp space for the Q stripe */ + q_sector.page = alloc_page(GFP_NOFS); + if (!q_sector.page) { + __free_page(p_sector.page); + p_sector.page = NULL; + goto cleanup; + } + q_sector.pgoff = 0; + q_sector.uptodate = 1; + pointers[rbio->real_stripes - 1] = kmap_local_page(q_sector.page); + } + + atomic_set(&rbio->error, 0); + + /* Map the parity stripe just once */ + pointers[nr_data] = kmap_local_page(p_sector.page); + + for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) { + struct sector_ptr *sector; + void *parity; + + /* first collect one page from each data stripe */ + for (stripe = 0; stripe < nr_data; stripe++) { + sector = sector_in_rbio(rbio, stripe, sectornr, 0); + pointers[stripe] = kmap_local_page(sector->page) + + sector->pgoff; + } + + if (has_qstripe) { + /* RAID6, call the library function to fill in our P/Q */ + raid6_call.gen_syndrome(rbio->real_stripes, sectorsize, + pointers); + } else { + /* raid5 */ + memcpy(pointers[nr_data], pointers[0], sectorsize); + run_xor(pointers + 1, nr_data - 1, sectorsize); + } + + /* Check scrubbing parity and repair it */ + sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr); + parity = kmap_local_page(sector->page) + sector->pgoff; + if (memcmp(parity, pointers[rbio->scrubp], sectorsize) != 0) + memcpy(parity, pointers[rbio->scrubp], sectorsize); + else + /* Parity is right, needn't writeback */ + bitmap_clear(&rbio->dbitmap, sectornr, 1); + kunmap_local(parity); + + for (stripe = nr_data - 1; stripe >= 0; stripe--) + kunmap_local(pointers[stripe]); + } + + kunmap_local(pointers[nr_data]); + __free_page(p_sector.page); + p_sector.page = NULL; + if (q_sector.page) { + kunmap_local(pointers[rbio->real_stripes - 1]); + __free_page(q_sector.page); + q_sector.page = NULL; + } + +writeback: + /* + * time to start writing. Make bios for everything from the + * higher layers (the bio_list in our rbio) and our p/q. Ignore + * everything else. + */ + for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) { + struct sector_ptr *sector; + + sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr); + ret = rbio_add_io_sector(rbio, &bio_list, sector, rbio->scrubp, + sectornr, REQ_OP_WRITE); + if (ret) + goto cleanup; + } + + if (!is_replace) + goto submit_write; + + for_each_set_bit(sectornr, pbitmap, rbio->stripe_nsectors) { + struct sector_ptr *sector; + + sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr); + ret = rbio_add_io_sector(rbio, &bio_list, sector, + bioc->tgtdev_map[rbio->scrubp], + sectornr, REQ_OP_WRITE); + if (ret) + goto cleanup; + } + +submit_write: + nr_data = bio_list_size(&bio_list); + if (!nr_data) { + /* Every parity is right */ + rbio_orig_end_io(rbio, BLK_STS_OK); + return; + } + + atomic_set(&rbio->stripes_pending, nr_data); + + while ((bio = bio_list_pop(&bio_list))) { + bio->bi_end_io = raid_write_end_io; + + if (trace_raid56_scrub_write_stripe_enabled()) { + struct raid56_bio_trace_info trace_info = { 0 }; + + bio_get_trace_info(rbio, bio, &trace_info); + trace_raid56_scrub_write_stripe(rbio, bio, &trace_info); + } + submit_bio(bio); + } + return; + +cleanup: + rbio_orig_end_io(rbio, BLK_STS_IOERR); + + while ((bio = bio_list_pop(&bio_list))) + bio_put(bio); +} + +static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe) +{ + if (stripe >= 0 && stripe < rbio->nr_data) + return 1; + return 0; +} + +/* + * While we're doing the parity check and repair, we could have errors + * in reading pages off the disk. This checks for errors and if we're + * not able to read the page it'll trigger parity reconstruction. The + * parity scrub will be finished after we've reconstructed the failed + * stripes + */ +static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio) +{ + if (atomic_read(&rbio->error) > rbio->bioc->max_errors) + goto cleanup; + + if (rbio->faila >= 0 || rbio->failb >= 0) { + int dfail = 0, failp = -1; + + if (is_data_stripe(rbio, rbio->faila)) + dfail++; + else if (is_parity_stripe(rbio->faila)) + failp = rbio->faila; + + if (is_data_stripe(rbio, rbio->failb)) + dfail++; + else if (is_parity_stripe(rbio->failb)) + failp = rbio->failb; + + /* + * Because we can not use a scrubbing parity to repair + * the data, so the capability of the repair is declined. + * (In the case of RAID5, we can not repair anything) + */ + if (dfail > rbio->bioc->max_errors - 1) + goto cleanup; + + /* + * If all data is good, only parity is correctly, just + * repair the parity. + */ + if (dfail == 0) { + finish_parity_scrub(rbio, 0); + return; + } + + /* + * Here means we got one corrupted data stripe and one + * corrupted parity on RAID6, if the corrupted parity + * is scrubbing parity, luckily, use the other one to repair + * the data, or we can not repair the data stripe. + */ + if (failp != rbio->scrubp) + goto cleanup; + + __raid_recover_end_io(rbio); + } else { + finish_parity_scrub(rbio, 1); + } + return; + +cleanup: + rbio_orig_end_io(rbio, BLK_STS_IOERR); +} + +/* + * end io for the read phase of the rmw cycle. All the bios here are physical + * stripe bios we've read from the disk so we can recalculate the parity of the + * stripe. + * + * This will usually kick off finish_rmw once all the bios are read in, but it + * may trigger parity reconstruction if we had any errors along the way + */ +static void raid56_parity_scrub_end_io_work(struct work_struct *work) +{ + struct btrfs_raid_bio *rbio = + container_of(work, struct btrfs_raid_bio, end_io_work); + + /* + * This will normally call finish_rmw to start our write, but if there + * are any failed stripes we'll reconstruct from parity first + */ + validate_rbio_for_parity_scrub(rbio); +} + +static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio) +{ + int bios_to_read = 0; + struct bio_list bio_list; + int ret; + int total_sector_nr; + struct bio *bio; + + bio_list_init(&bio_list); + + ret = alloc_rbio_essential_pages(rbio); + if (ret) + goto cleanup; + + atomic_set(&rbio->error, 0); + /* Build a list of bios to read all the missing parts. */ + for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors; + total_sector_nr++) { + int sectornr = total_sector_nr % rbio->stripe_nsectors; + int stripe = total_sector_nr / rbio->stripe_nsectors; + struct sector_ptr *sector; + + /* No data in the vertical stripe, no need to read. */ + if (!test_bit(sectornr, &rbio->dbitmap)) + continue; + + /* + * We want to find all the sectors missing from the rbio and + * read them from the disk. If sector_in_rbio() finds a sector + * in the bio list we don't need to read it off the stripe. + */ + sector = sector_in_rbio(rbio, stripe, sectornr, 1); + if (sector) + continue; + + sector = rbio_stripe_sector(rbio, stripe, sectornr); + /* + * The bio cache may have handed us an uptodate sector. If so, + * use it. + */ + if (sector->uptodate) + continue; + + ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe, + sectornr, REQ_OP_READ); + if (ret) + goto cleanup; + } + + bios_to_read = bio_list_size(&bio_list); + if (!bios_to_read) { + /* + * this can happen if others have merged with + * us, it means there is nothing left to read. + * But if there are missing devices it may not be + * safe to do the full stripe write yet. + */ + goto finish; + } + + /* + * The bioc may be freed once we submit the last bio. Make sure not to + * touch it after that. + */ + atomic_set(&rbio->stripes_pending, bios_to_read); + INIT_WORK(&rbio->end_io_work, raid56_parity_scrub_end_io_work); + while ((bio = bio_list_pop(&bio_list))) { + bio->bi_end_io = raid56_bio_end_io; + + if (trace_raid56_scrub_read_enabled()) { + struct raid56_bio_trace_info trace_info = { 0 }; + + bio_get_trace_info(rbio, bio, &trace_info); + trace_raid56_scrub_read(rbio, bio, &trace_info); + } + submit_bio(bio); + } + /* the actual write will happen once the reads are done */ + return; + +cleanup: + rbio_orig_end_io(rbio, BLK_STS_IOERR); + + while ((bio = bio_list_pop(&bio_list))) + bio_put(bio); + + return; + +finish: + validate_rbio_for_parity_scrub(rbio); +} + +static void scrub_parity_work(struct work_struct *work) +{ + struct btrfs_raid_bio *rbio; + + rbio = container_of(work, struct btrfs_raid_bio, work); + raid56_parity_scrub_stripe(rbio); +} + +void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio) +{ + if (!lock_stripe_add(rbio)) + start_async_work(rbio, scrub_parity_work); +} + +/* The following code is used for dev replace of a missing RAID 5/6 device. */ + +struct btrfs_raid_bio * +raid56_alloc_missing_rbio(struct bio *bio, struct btrfs_io_context *bioc) +{ + struct btrfs_fs_info *fs_info = bioc->fs_info; + struct btrfs_raid_bio *rbio; + + rbio = alloc_rbio(fs_info, bioc); + if (IS_ERR(rbio)) + return NULL; + + rbio->operation = BTRFS_RBIO_REBUILD_MISSING; + bio_list_add(&rbio->bio_list, bio); + /* + * This is a special bio which is used to hold the completion handler + * and make the scrub rbio is similar to the other types + */ + ASSERT(!bio->bi_iter.bi_size); + + rbio->faila = find_logical_bio_stripe(rbio, bio); + if (rbio->faila == -1) { + btrfs_warn_rl(fs_info, + "can not determine the failed stripe number for full stripe %llu", + bioc->raid_map[0]); + __free_raid_bio(rbio); + return NULL; + } + + return rbio; +} + +void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio) +{ + if (!lock_stripe_add(rbio)) + start_async_work(rbio, read_rebuild_work); +} |