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-rw-r--r--fs/btrfs/raid56.c2782
1 files changed, 2782 insertions, 0 deletions
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
new file mode 100644
index 0000000000..3e014b9370
--- /dev/null
+++ b/fs/btrfs/raid56.c
@@ -0,0 +1,2782 @@
+// 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 "messages.h"
+#include "misc.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "volumes.h"
+#include "raid56.h"
+#include "async-thread.h"
+#include "file-item.h"
+#include "btrfs_inode.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 void rmw_rbio_work(struct work_struct *work);
+static void rmw_rbio_work_locked(struct work_struct *work);
+static void index_rbio_pages(struct btrfs_raid_bio *rbio);
+static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
+
+static int finish_parity_scrub(struct btrfs_raid_bio *rbio);
+static void scrub_rbio_work_locked(struct work_struct *work);
+
+static void free_raid_bio_pointers(struct btrfs_raid_bio *rbio)
+{
+ bitmap_free(rbio->error_bitmap);
+ kfree(rbio->stripe_pages);
+ kfree(rbio->bio_sectors);
+ kfree(rbio->stripe_sectors);
+ kfree(rbio->finish_pointers);
+}
+
+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);
+ free_raid_bio_pointers(rbio);
+ kfree(rbio);
+}
+
+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) {
+ /*
+ * Even if the sector is not covered by bio, if it is
+ * a data sector it should still be uptodate as it is
+ * read from disk.
+ */
+ if (i < rbio->nr_data * rbio->stripe_nsectors)
+ ASSERT(rbio->stripe_sectors[i].uptodate);
+ 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->full_stripe_logical;
+
+ /*
+ * 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;
+}
+
+static bool is_data_stripe_page(struct btrfs_raid_bio *rbio, int page_nr)
+{
+ const int sector_nr = (page_nr << PAGE_SHIFT) >>
+ rbio->bioc->fs_info->sectorsize_bits;
+
+ /*
+ * We have ensured PAGE_SIZE is aligned with sectorsize, thus
+ * we won't have a page which is half data half parity.
+ *
+ * Thus if the first sector of the page belongs to data stripes, then
+ * the full page belongs to data stripes.
+ */
+ return (sector_nr < rbio->nr_data * rbio->stripe_nsectors);
+}
+
+/*
+ * 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;
+
+ if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
+ return;
+
+ for (i = 0; i < dest->nr_pages; i++) {
+ struct page *p = src->stripe_pages[i];
+
+ /*
+ * We don't need to steal P/Q pages as they will always be
+ * regenerated for RMW or full write anyway.
+ */
+ if (!is_data_stripe_page(src, i))
+ continue;
+
+ /*
+ * If @src already has RBIO_CACHE_READY_BIT, it should have
+ * all data stripe pages present and uptodate.
+ */
+ ASSERT(p);
+ ASSERT(full_page_sectors_uptodate(src, i));
+ 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;
+
+ if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
+ return;
+
+ table = rbio->bioc->fs_info->stripe_hash_table;
+
+ spin_lock(&table->cache_lock);
+ __remove_rbio_from_cache(rbio);
+ spin_unlock(&table->cache_lock);
+}
+
+/*
+ * remove everything in the cache
+ */
+static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
+{
+ struct btrfs_stripe_hash_table *table;
+ struct btrfs_raid_bio *rbio;
+
+ table = info->stripe_hash_table;
+
+ spin_lock(&table->cache_lock);
+ 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(&table->cache_lock);
+}
+
+/*
+ * 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;
+
+ if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
+ return;
+
+ table = rbio->bioc->fs_info->stripe_hash_table;
+
+ spin_lock(&table->cache_lock);
+ 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(&table->cache_lock);
+}
+
+/*
+ * 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 size = rbio->bio_list_bytes;
+ int ret = 1;
+
+ spin_lock(&rbio->bio_list_lock);
+ if (size != rbio->nr_data * BTRFS_STRIPE_LEN)
+ ret = 0;
+ BUG_ON(size > rbio->nr_data * BTRFS_STRIPE_LEN);
+ spin_unlock(&rbio->bio_list_lock);
+
+ 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->full_stripe_logical != cur->bioc->full_stripe_logical)
+ 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_READ_REBUILD)
+ 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;
+ 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(&h->lock);
+ list_for_each_entry(cur, &h->hash_list, hash_list) {
+ if (cur->bioc->full_stripe_logical != rbio->bioc->full_stripe_logical)
+ 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(&h->lock);
+ if (cache_drop)
+ remove_rbio_from_cache(cache_drop);
+ if (freeit)
+ free_raid_bio(freeit);
+ return ret;
+}
+
+static void recover_rbio_work_locked(struct work_struct *work);
+
+/*
+ * 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;
+ 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(&h->lock);
+ 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(&h->lock);
+
+ if (next->operation == BTRFS_RBIO_READ_REBUILD) {
+ start_async_work(next, recover_rbio_work_locked);
+ } else if (next->operation == BTRFS_RBIO_WRITE) {
+ steal_rbio(rbio, next);
+ start_async_work(next, rmw_rbio_work_locked);
+ } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
+ steal_rbio(rbio, next);
+ start_async_work(next, scrub_rbio_work_locked);
+ }
+
+ goto done_nolock;
+ }
+ }
+done:
+ spin_unlock(&rbio->bio_list_lock);
+ spin_unlock(&h->lock);
+
+done_nolock:
+ if (!keep_cache)
+ remove_rbio_from_cache(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;
+
+ kfree(rbio->csum_buf);
+ bitmap_free(rbio->csum_bitmap);
+ rbio->csum_buf = NULL;
+ rbio->csum_bitmap = NULL;
+
+ /*
+ * 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);
+}
+
+/*
+ * 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(&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(&rbio->bio_list_lock);
+ return sector;
+ }
+ spin_unlock(&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->replace_nr_stripes;
+ 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;
+
+ /* 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), GFP_NOFS);
+ if (!rbio)
+ return ERR_PTR(-ENOMEM);
+ rbio->stripe_pages = kcalloc(num_pages, sizeof(struct page *),
+ GFP_NOFS);
+ rbio->bio_sectors = kcalloc(num_sectors, sizeof(struct sector_ptr),
+ GFP_NOFS);
+ rbio->stripe_sectors = kcalloc(num_sectors, sizeof(struct sector_ptr),
+ GFP_NOFS);
+ rbio->finish_pointers = kcalloc(real_stripes, sizeof(void *), GFP_NOFS);
+ rbio->error_bitmap = bitmap_zalloc(num_sectors, GFP_NOFS);
+
+ if (!rbio->stripe_pages || !rbio->bio_sectors || !rbio->stripe_sectors ||
+ !rbio->finish_pointers || !rbio->error_bitmap) {
+ free_raid_bio_pointers(rbio);
+ kfree(rbio);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ bio_list_init(&rbio->bio_list);
+ init_waitqueue_head(&rbio->io_wait);
+ 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;
+ refcount_set(&rbio->refs, 1);
+ atomic_set(&rbio->stripes_pending, 0);
+
+ 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;
+}
+
+/*
+ * Return the total number of errors found in the vertical stripe of @sector_nr.
+ *
+ * @faila and @failb will also be updated to the first and second stripe
+ * number of the errors.
+ */
+static int get_rbio_veritical_errors(struct btrfs_raid_bio *rbio, int sector_nr,
+ int *faila, int *failb)
+{
+ int stripe_nr;
+ int found_errors = 0;
+
+ if (faila || failb) {
+ /*
+ * Both @faila and @failb should be valid pointers if any of
+ * them is specified.
+ */
+ ASSERT(faila && failb);
+ *faila = -1;
+ *failb = -1;
+ }
+
+ for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
+ int total_sector_nr = stripe_nr * rbio->stripe_nsectors + sector_nr;
+
+ if (test_bit(total_sector_nr, rbio->error_bitmap)) {
+ found_errors++;
+ if (faila) {
+ /* Update faila and failb. */
+ if (*faila < 0)
+ *faila = stripe_nr;
+ else if (*failb < 0)
+ *failb = stripe_nr;
+ }
+ }
+ }
+ return found_errors;
+}
+
+/*
+ * 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) {
+ int found_errors;
+
+ set_bit(stripe_nr * rbio->stripe_nsectors + sector_nr,
+ rbio->error_bitmap);
+
+ /* Check if we have reached tolerance early. */
+ found_errors = get_rbio_veritical_errors(rbio, sector_nr,
+ NULL, NULL);
+ if (found_errors > rbio->bioc->max_errors)
+ return -EIO;
+ return 0;
+ }
+
+ /* see if we can add this page onto our existing bio */
+ if (last) {
+ u64 last_end = last->bi_iter.bi_sector << SECTOR_SHIFT;
+ 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 >> SECTOR_SHIFT;
+ bio->bi_private = rbio;
+
+ __bio_add_page(bio, sector->page, sectorsize, sector->pgoff);
+ bio_list_add(bio_list, bio);
+ return 0;
+}
+
+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->full_stripe_logical;
+
+ 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(&rbio->bio_list_lock);
+ bio_list_for_each(bio, &rbio->bio_list)
+ index_one_bio(rbio, bio);
+
+ spin_unlock(&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;
+}
+
+static inline void bio_list_put(struct bio_list *bio_list)
+{
+ struct bio *bio;
+
+ while ((bio = bio_list_pop(bio_list)))
+ bio_put(bio);
+}
+
+/* Generate PQ for one vertical stripe. */
+static void generate_pq_vertical(struct btrfs_raid_bio *rbio, int sectornr)
+{
+ void **pointers = rbio->finish_pointers;
+ const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
+ struct sector_ptr *sector;
+ int stripe;
+ const bool has_qstripe = rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6;
+
+ /* First collect one sector from each data stripe */
+ for (stripe = 0; stripe < rbio->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[rbio->nr_data], pointers[0], sectorsize);
+ run_xor(pointers + 1, rbio->nr_data - 1, sectorsize);
+ }
+ for (stripe = stripe - 1; stripe >= 0; stripe--)
+ kunmap_local(pointers[stripe]);
+}
+
+static int rmw_assemble_write_bios(struct btrfs_raid_bio *rbio,
+ struct bio_list *bio_list)
+{
+ /* The total sector number inside the full stripe. */
+ int total_sector_nr;
+ int sectornr;
+ int stripe;
+ int ret;
+
+ ASSERT(bio_list_size(bio_list) == 0);
+
+ /* We should have at least one data sector. */
+ ASSERT(bitmap_weight(&rbio->dbitmap, rbio->stripe_nsectors));
+
+ /*
+ * Reset errors, as we may have errors inherited from from degraded
+ * write.
+ */
+ bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
+
+ /*
+ * Start assembly. 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 error;
+ }
+
+ if (likely(!rbio->bioc->replace_nr_stripes))
+ return 0;
+
+ /*
+ * Make a copy for the replace target device.
+ *
+ * Thus the source stripe number (in replace_stripe_src) should be valid.
+ */
+ ASSERT(rbio->bioc->replace_stripe_src >= 0);
+
+ 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;
+
+ /*
+ * For RAID56, there is only one device that can be replaced,
+ * and replace_stripe_src[0] indicates the stripe number we
+ * need to copy from.
+ */
+ if (stripe != rbio->bioc->replace_stripe_src) {
+ /*
+ * 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->real_stripes,
+ sectornr, REQ_OP_WRITE);
+ if (ret)
+ goto error;
+ }
+
+ return 0;
+error:
+ bio_list_put(bio_list);
+ return -EIO;
+}
+
+static void set_rbio_range_error(struct btrfs_raid_bio *rbio, struct bio *bio)
+{
+ struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
+ u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
+ rbio->bioc->full_stripe_logical;
+ int total_nr_sector = offset >> fs_info->sectorsize_bits;
+
+ ASSERT(total_nr_sector < rbio->nr_data * rbio->stripe_nsectors);
+
+ bitmap_set(rbio->error_bitmap, total_nr_sector,
+ bio->bi_iter.bi_size >> fs_info->sectorsize_bits);
+
+ /*
+ * Special handling for raid56_alloc_missing_rbio() used by
+ * scrub/replace. Unlike call path in raid56_parity_recover(), they
+ * pass an empty bio here. Thus we have to find out the missing device
+ * and mark the stripe error instead.
+ */
+ if (bio->bi_iter.bi_size == 0) {
+ bool found_missing = false;
+ int stripe_nr;
+
+ for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
+ if (!rbio->bioc->stripes[stripe_nr].dev->bdev) {
+ found_missing = true;
+ bitmap_set(rbio->error_bitmap,
+ stripe_nr * rbio->stripe_nsectors,
+ rbio->stripe_nsectors);
+ }
+ }
+ ASSERT(found_missing);
+ }
+}
+
+/*
+ * For subpage case, we can no longer set page Up-to-date 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 int get_bio_sector_nr(struct btrfs_raid_bio *rbio, struct bio *bio)
+{
+ struct bio_vec *bv = bio_first_bvec_all(bio);
+ int i;
+
+ for (i = 0; i < rbio->nr_sectors; i++) {
+ struct sector_ptr *sector;
+
+ sector = &rbio->stripe_sectors[i];
+ if (sector->page == bv->bv_page && sector->pgoff == bv->bv_offset)
+ break;
+ sector = &rbio->bio_sectors[i];
+ if (sector->page == bv->bv_page && sector->pgoff == bv->bv_offset)
+ break;
+ }
+ ASSERT(i < rbio->nr_sectors);
+ return i;
+}
+
+static void rbio_update_error_bitmap(struct btrfs_raid_bio *rbio, struct bio *bio)
+{
+ int total_sector_nr = get_bio_sector_nr(rbio, bio);
+ u32 bio_size = 0;
+ struct bio_vec *bvec;
+ int i;
+
+ bio_for_each_bvec_all(bvec, bio, i)
+ bio_size += bvec->bv_len;
+
+ /*
+ * Since we can have multiple bios touching the error_bitmap, we cannot
+ * call bitmap_set() without protection.
+ *
+ * Instead use set_bit() for each bit, as set_bit() itself is atomic.
+ */
+ for (i = total_sector_nr; i < total_sector_nr +
+ (bio_size >> rbio->bioc->fs_info->sectorsize_bits); i++)
+ set_bit(i, rbio->error_bitmap);
+}
+
+/* Verify the data sectors at read time. */
+static void verify_bio_data_sectors(struct btrfs_raid_bio *rbio,
+ struct bio *bio)
+{
+ struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
+ int total_sector_nr = get_bio_sector_nr(rbio, bio);
+ struct bio_vec *bvec;
+ struct bvec_iter_all iter_all;
+
+ /* No data csum for the whole stripe, no need to verify. */
+ if (!rbio->csum_bitmap || !rbio->csum_buf)
+ return;
+
+ /* P/Q stripes, they have no data csum to verify against. */
+ if (total_sector_nr >= rbio->nr_data * rbio->stripe_nsectors)
+ return;
+
+ bio_for_each_segment_all(bvec, bio, iter_all) {
+ int bv_offset;
+
+ for (bv_offset = bvec->bv_offset;
+ bv_offset < bvec->bv_offset + bvec->bv_len;
+ bv_offset += fs_info->sectorsize, total_sector_nr++) {
+ u8 csum_buf[BTRFS_CSUM_SIZE];
+ u8 *expected_csum = rbio->csum_buf +
+ total_sector_nr * fs_info->csum_size;
+ int ret;
+
+ /* No csum for this sector, skip to the next sector. */
+ if (!test_bit(total_sector_nr, rbio->csum_bitmap))
+ continue;
+
+ ret = btrfs_check_sector_csum(fs_info, bvec->bv_page,
+ bv_offset, csum_buf, expected_csum);
+ if (ret < 0)
+ set_bit(total_sector_nr, rbio->error_bitmap);
+ }
+ }
+}
+
+static void raid_wait_read_end_io(struct bio *bio)
+{
+ struct btrfs_raid_bio *rbio = bio->bi_private;
+
+ if (bio->bi_status) {
+ rbio_update_error_bitmap(rbio, bio);
+ } else {
+ set_bio_pages_uptodate(rbio, bio);
+ verify_bio_data_sectors(rbio, bio);
+ }
+
+ bio_put(bio);
+ if (atomic_dec_and_test(&rbio->stripes_pending))
+ wake_up(&rbio->io_wait);
+}
+
+static void submit_read_wait_bio_list(struct btrfs_raid_bio *rbio,
+ struct bio_list *bio_list)
+{
+ struct bio *bio;
+
+ atomic_set(&rbio->stripes_pending, bio_list_size(bio_list));
+ while ((bio = bio_list_pop(bio_list))) {
+ bio->bi_end_io = raid_wait_read_end_io;
+
+ if (trace_raid56_read_enabled()) {
+ struct raid56_bio_trace_info trace_info = { 0 };
+
+ bio_get_trace_info(rbio, bio, &trace_info);
+ trace_raid56_read(rbio, bio, &trace_info);
+ }
+ submit_bio(bio);
+ }
+
+ wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
+}
+
+static int alloc_rbio_data_pages(struct btrfs_raid_bio *rbio)
+{
+ const int data_pages = rbio->nr_data * rbio->stripe_npages;
+ int ret;
+
+ ret = btrfs_alloc_page_array(data_pages, rbio->stripe_pages);
+ if (ret < 0)
+ return ret;
+
+ index_stripe_sectors(rbio);
+ return 0;
+}
+
+/*
+ * 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 raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
+{
+ struct btrfs_plug_cb *plug = container_of(cb, struct btrfs_plug_cb, cb);
+ struct btrfs_raid_bio *cur;
+ struct btrfs_raid_bio *last = NULL;
+
+ 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)) {
+ /* We have a full stripe, queue it down. */
+ start_async_work(cur, rmw_rbio_work);
+ continue;
+ }
+ if (last) {
+ if (rbio_can_merge(last, cur)) {
+ merge_rbio(last, cur);
+ free_raid_bio(cur);
+ continue;
+ }
+ start_async_work(last, rmw_rbio_work);
+ }
+ last = cur;
+ }
+ if (last)
+ start_async_work(last, rmw_rbio_work);
+ kfree(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->full_stripe_logical;
+ 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;
+
+ rbio = alloc_rbio(fs_info, bioc);
+ if (IS_ERR(rbio)) {
+ bio->bi_status = errno_to_blk_status(PTR_ERR(rbio));
+ bio_endio(bio);
+ return;
+ }
+ 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)) {
+ cb = blk_check_plugged(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);
+ return;
+ }
+ }
+
+ /*
+ * Either we don't have any existing plug, or we're doing a full stripe,
+ * queue the rmw work now.
+ */
+ start_async_work(rbio, rmw_rbio_work);
+}
+
+static int verify_one_sector(struct btrfs_raid_bio *rbio,
+ int stripe_nr, int sector_nr)
+{
+ struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
+ struct sector_ptr *sector;
+ u8 csum_buf[BTRFS_CSUM_SIZE];
+ u8 *csum_expected;
+ int ret;
+
+ if (!rbio->csum_bitmap || !rbio->csum_buf)
+ return 0;
+
+ /* No way to verify P/Q as they are not covered by data csum. */
+ if (stripe_nr >= rbio->nr_data)
+ return 0;
+ /*
+ * If we're rebuilding a read, we have to use pages from the
+ * bio list if possible.
+ */
+ if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
+ sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
+ } else {
+ sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
+ }
+
+ ASSERT(sector->page);
+
+ csum_expected = rbio->csum_buf +
+ (stripe_nr * rbio->stripe_nsectors + sector_nr) *
+ fs_info->csum_size;
+ ret = btrfs_check_sector_csum(fs_info, sector->page, sector->pgoff,
+ csum_buf, csum_expected);
+ return ret;
+}
+
+/*
+ * Recover a vertical stripe specified by @sector_nr.
+ * @*pointers are the pre-allocated pointers by the caller, so we don't
+ * need to allocate/free the pointers again and again.
+ */
+static int recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
+ void **pointers, void **unmap_array)
+{
+ struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
+ struct sector_ptr *sector;
+ const u32 sectorsize = fs_info->sectorsize;
+ int found_errors;
+ int faila;
+ int failb;
+ int stripe_nr;
+ int ret = 0;
+
+ /*
+ * 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(sector_nr, &rbio->dbitmap))
+ return 0;
+
+ found_errors = get_rbio_veritical_errors(rbio, sector_nr, &faila,
+ &failb);
+ /*
+ * No errors in the vertical stripe, skip it. Can happen for recovery
+ * which only part of a stripe failed csum check.
+ */
+ if (!found_errors)
+ return 0;
+
+ if (found_errors > rbio->bioc->max_errors)
+ return -EIO;
+
+ /*
+ * Setup our array of pointers with sectors from each stripe
+ *
+ * NOTE: store a duplicate array of pointers to preserve the
+ * pointer order.
+ */
+ for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
+ /*
+ * If we're rebuilding a read, we have to use pages from the
+ * bio list if possible.
+ */
+ if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
+ sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
+ } else {
+ sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
+ }
+ ASSERT(sector->page);
+ pointers[stripe_nr] = kmap_local_page(sector->page) +
+ sector->pgoff;
+ unmap_array[stripe_nr] = pointers[stripe_nr];
+ }
+
+ /* 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.
+ * We have nothing to do, just skip the
+ * recovery for this stripe.
+ */
+ goto cleanup;
+ /*
+ * a single failure in raid6 is rebuilt
+ * in the pstripe code below
+ */
+ goto pstripe;
+ }
+
+ /*
+ * 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 (failb == rbio->real_stripes - 1) {
+ if (faila == rbio->real_stripes - 2)
+ /*
+ * Only P and Q are corrupted.
+ * We only care about data stripes recovery,
+ * can skip this vertical stripe.
+ */
+ goto cleanup;
+ /*
+ * Otherwise we have one bad data stripe and
+ * a good P stripe. raid5!
+ */
+ goto pstripe;
+ }
+
+ if (failb == rbio->real_stripes - 2) {
+ 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). */
+ ASSERT(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_nr = faila; stripe_nr < rbio->nr_data - 1;
+ stripe_nr++)
+ pointers[stripe_nr] = pointers[stripe_nr + 1];
+ pointers[rbio->nr_data - 1] = p;
+
+ /* Xor in the rest */
+ run_xor(pointers, rbio->nr_data - 1, sectorsize);
+
+ }
+
+ /*
+ * No matter if this is a RMW or recovery, we should have all
+ * failed sectors repaired in the vertical stripe, thus they are now
+ * uptodate.
+ * Especially if we determine to cache the rbio, we need to
+ * have at least all data sectors uptodate.
+ *
+ * If possible, also check if the repaired sector matches its data
+ * checksum.
+ */
+ if (faila >= 0) {
+ ret = verify_one_sector(rbio, faila, sector_nr);
+ if (ret < 0)
+ goto cleanup;
+
+ sector = rbio_stripe_sector(rbio, faila, sector_nr);
+ sector->uptodate = 1;
+ }
+ if (failb >= 0) {
+ ret = verify_one_sector(rbio, failb, sector_nr);
+ if (ret < 0)
+ goto cleanup;
+
+ sector = rbio_stripe_sector(rbio, failb, sector_nr);
+ sector->uptodate = 1;
+ }
+
+cleanup:
+ for (stripe_nr = rbio->real_stripes - 1; stripe_nr >= 0; stripe_nr--)
+ kunmap_local(unmap_array[stripe_nr]);
+ return ret;
+}
+
+static int recover_sectors(struct btrfs_raid_bio *rbio)
+{
+ void **pointers = NULL;
+ void **unmap_array = NULL;
+ int sectornr;
+ int ret = 0;
+
+ /*
+ * @pointers array stores the pointer for each sector.
+ *
+ * @unmap_array stores copy of pointers that does not get reordered
+ * during reconstruction so that kunmap_local works.
+ */
+ pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
+ unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
+ if (!pointers || !unmap_array) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
+ spin_lock(&rbio->bio_list_lock);
+ set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
+ spin_unlock(&rbio->bio_list_lock);
+ }
+
+ index_rbio_pages(rbio);
+
+ for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
+ ret = recover_vertical(rbio, sectornr, pointers, unmap_array);
+ if (ret < 0)
+ break;
+ }
+
+out:
+ kfree(pointers);
+ kfree(unmap_array);
+ return ret;
+}
+
+static void recover_rbio(struct btrfs_raid_bio *rbio)
+{
+ struct bio_list bio_list = BIO_EMPTY_LIST;
+ int total_sector_nr;
+ int ret = 0;
+
+ /*
+ * Either we're doing recover for a read failure or degraded write,
+ * caller should have set error bitmap correctly.
+ */
+ ASSERT(bitmap_weight(rbio->error_bitmap, rbio->nr_sectors));
+
+ /* For recovery, we need to read all sectors including P/Q. */
+ ret = alloc_rbio_pages(rbio);
+ if (ret < 0)
+ goto out;
+
+ index_rbio_pages(rbio);
+
+ /*
+ * 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;
+
+ /*
+ * Skip the range which has error. It can be a range which is
+ * marked error (for csum mismatch), or it can be a missing
+ * device.
+ */
+ if (!rbio->bioc->stripes[stripe].dev->bdev ||
+ test_bit(total_sector_nr, rbio->error_bitmap)) {
+ /*
+ * Also set the error bit for missing device, which
+ * may not yet have its error bit set.
+ */
+ set_bit(total_sector_nr, rbio->error_bitmap);
+ 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) {
+ bio_list_put(&bio_list);
+ goto out;
+ }
+ }
+
+ submit_read_wait_bio_list(rbio, &bio_list);
+ ret = recover_sectors(rbio);
+out:
+ rbio_orig_end_io(rbio, errno_to_blk_status(ret));
+}
+
+static void recover_rbio_work(struct work_struct *work)
+{
+ struct btrfs_raid_bio *rbio;
+
+ rbio = container_of(work, struct btrfs_raid_bio, work);
+ if (!lock_stripe_add(rbio))
+ recover_rbio(rbio);
+}
+
+static void recover_rbio_work_locked(struct work_struct *work)
+{
+ recover_rbio(container_of(work, struct btrfs_raid_bio, work));
+}
+
+static void set_rbio_raid6_extra_error(struct btrfs_raid_bio *rbio, int mirror_num)
+{
+ bool found = false;
+ int sector_nr;
+
+ /*
+ * This is for RAID6 extra recovery tries, thus mirror number should
+ * be large than 2.
+ * Mirror 1 means read from data stripes. Mirror 2 means rebuild using
+ * RAID5 methods.
+ */
+ ASSERT(mirror_num > 2);
+ for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
+ int found_errors;
+ int faila;
+ int failb;
+
+ found_errors = get_rbio_veritical_errors(rbio, sector_nr,
+ &faila, &failb);
+ /* This vertical stripe doesn't have errors. */
+ if (!found_errors)
+ continue;
+
+ /*
+ * If we found errors, there should be only one error marked
+ * by previous set_rbio_range_error().
+ */
+ ASSERT(found_errors == 1);
+ found = true;
+
+ /* Now select another stripe to mark as error. */
+ failb = rbio->real_stripes - (mirror_num - 1);
+ if (failb <= faila)
+ failb--;
+
+ /* Set the extra bit in error bitmap. */
+ if (failb >= 0)
+ set_bit(failb * rbio->stripe_nsectors + sector_nr,
+ rbio->error_bitmap);
+ }
+
+ /* We should found at least one vertical stripe with error.*/
+ ASSERT(found);
+}
+
+/*
+ * 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));
+ bio_endio(bio);
+ return;
+ }
+
+ rbio->operation = BTRFS_RBIO_READ_REBUILD;
+ rbio_add_bio(rbio, bio);
+
+ set_rbio_range_error(rbio, 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)
+ set_rbio_raid6_extra_error(rbio, mirror_num);
+
+ start_async_work(rbio, recover_rbio_work);
+}
+
+static void fill_data_csums(struct btrfs_raid_bio *rbio)
+{
+ struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
+ struct btrfs_root *csum_root = btrfs_csum_root(fs_info,
+ rbio->bioc->full_stripe_logical);
+ const u64 start = rbio->bioc->full_stripe_logical;
+ const u32 len = (rbio->nr_data * rbio->stripe_nsectors) <<
+ fs_info->sectorsize_bits;
+ int ret;
+
+ /* The rbio should not have its csum buffer initialized. */
+ ASSERT(!rbio->csum_buf && !rbio->csum_bitmap);
+
+ /*
+ * Skip the csum search if:
+ *
+ * - The rbio doesn't belong to data block groups
+ * Then we are doing IO for tree blocks, no need to search csums.
+ *
+ * - The rbio belongs to mixed block groups
+ * This is to avoid deadlock, as we're already holding the full
+ * stripe lock, if we trigger a metadata read, and it needs to do
+ * raid56 recovery, we will deadlock.
+ */
+ if (!(rbio->bioc->map_type & BTRFS_BLOCK_GROUP_DATA) ||
+ rbio->bioc->map_type & BTRFS_BLOCK_GROUP_METADATA)
+ return;
+
+ rbio->csum_buf = kzalloc(rbio->nr_data * rbio->stripe_nsectors *
+ fs_info->csum_size, GFP_NOFS);
+ rbio->csum_bitmap = bitmap_zalloc(rbio->nr_data * rbio->stripe_nsectors,
+ GFP_NOFS);
+ if (!rbio->csum_buf || !rbio->csum_bitmap) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ ret = btrfs_lookup_csums_bitmap(csum_root, NULL, start, start + len - 1,
+ rbio->csum_buf, rbio->csum_bitmap);
+ if (ret < 0)
+ goto error;
+ if (bitmap_empty(rbio->csum_bitmap, len >> fs_info->sectorsize_bits))
+ goto no_csum;
+ return;
+
+error:
+ /*
+ * We failed to allocate memory or grab the csum, but it's not fatal,
+ * we can still continue. But better to warn users that RMW is no
+ * longer safe for this particular sub-stripe write.
+ */
+ btrfs_warn_rl(fs_info,
+"sub-stripe write for full stripe %llu is not safe, failed to get csum: %d",
+ rbio->bioc->full_stripe_logical, ret);
+no_csum:
+ kfree(rbio->csum_buf);
+ bitmap_free(rbio->csum_bitmap);
+ rbio->csum_buf = NULL;
+ rbio->csum_bitmap = NULL;
+}
+
+static int rmw_read_wait_recover(struct btrfs_raid_bio *rbio)
+{
+ struct bio_list bio_list = BIO_EMPTY_LIST;
+ int total_sector_nr;
+ int ret = 0;
+
+ /*
+ * Fill the data csums we need for data verification. We need to fill
+ * the csum_bitmap/csum_buf first, as our endio function will try to
+ * verify the data sectors.
+ */
+ fill_data_csums(rbio);
+
+ /*
+ * Build a list of bios to read all sectors (including data and P/Q).
+ *
+ * This behavior is to compensate the later csum verification and recovery.
+ */
+ for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
+ total_sector_nr++) {
+ struct sector_ptr *sector;
+ int stripe = total_sector_nr / rbio->stripe_nsectors;
+ int sectornr = total_sector_nr % rbio->stripe_nsectors;
+
+ sector = rbio_stripe_sector(rbio, stripe, sectornr);
+ ret = rbio_add_io_sector(rbio, &bio_list, sector,
+ stripe, sectornr, REQ_OP_READ);
+ if (ret) {
+ bio_list_put(&bio_list);
+ return ret;
+ }
+ }
+
+ /*
+ * We may or may not have any corrupted sectors (including missing dev
+ * and csum mismatch), just let recover_sectors() to handle them all.
+ */
+ submit_read_wait_bio_list(rbio, &bio_list);
+ return recover_sectors(rbio);
+}
+
+static void raid_wait_write_end_io(struct bio *bio)
+{
+ struct btrfs_raid_bio *rbio = bio->bi_private;
+ blk_status_t err = bio->bi_status;
+
+ if (err)
+ rbio_update_error_bitmap(rbio, bio);
+ bio_put(bio);
+ if (atomic_dec_and_test(&rbio->stripes_pending))
+ wake_up(&rbio->io_wait);
+}
+
+static void submit_write_bios(struct btrfs_raid_bio *rbio,
+ struct bio_list *bio_list)
+{
+ struct bio *bio;
+
+ atomic_set(&rbio->stripes_pending, bio_list_size(bio_list));
+ while ((bio = bio_list_pop(bio_list))) {
+ bio->bi_end_io = raid_wait_write_end_io;
+
+ if (trace_raid56_write_enabled()) {
+ struct raid56_bio_trace_info trace_info = { 0 };
+
+ bio_get_trace_info(rbio, bio, &trace_info);
+ trace_raid56_write(rbio, bio, &trace_info);
+ }
+ submit_bio(bio);
+ }
+}
+
+/*
+ * To determine if we need to read any sector from the disk.
+ * Should only be utilized in RMW path, to skip cached rbio.
+ */
+static bool need_read_stripe_sectors(struct btrfs_raid_bio *rbio)
+{
+ int i;
+
+ for (i = 0; i < rbio->nr_data * rbio->stripe_nsectors; i++) {
+ struct sector_ptr *sector = &rbio->stripe_sectors[i];
+
+ /*
+ * We have a sector which doesn't have page nor uptodate,
+ * thus this rbio can not be cached one, as cached one must
+ * have all its data sectors present and uptodate.
+ */
+ if (!sector->page || !sector->uptodate)
+ return true;
+ }
+ return false;
+}
+
+static void rmw_rbio(struct btrfs_raid_bio *rbio)
+{
+ struct bio_list bio_list;
+ int sectornr;
+ int ret = 0;
+
+ /*
+ * Allocate the pages for parity first, as P/Q pages will always be
+ * needed for both full-stripe and sub-stripe writes.
+ */
+ ret = alloc_rbio_parity_pages(rbio);
+ if (ret < 0)
+ goto out;
+
+ /*
+ * Either full stripe write, or we have every data sector already
+ * cached, can go to write path immediately.
+ */
+ if (!rbio_is_full(rbio) && need_read_stripe_sectors(rbio)) {
+ /*
+ * Now we're doing sub-stripe write, also need all data stripes
+ * to do the full RMW.
+ */
+ ret = alloc_rbio_data_pages(rbio);
+ if (ret < 0)
+ goto out;
+
+ index_rbio_pages(rbio);
+
+ ret = rmw_read_wait_recover(rbio);
+ if (ret < 0)
+ goto out;
+ }
+
+ /*
+ * At this stage we're not allowed to add any new bios to the
+ * bio list any more, anyone else that wants to change this stripe
+ * needs to do their own rmw.
+ */
+ spin_lock(&rbio->bio_list_lock);
+ set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
+ spin_unlock(&rbio->bio_list_lock);
+
+ bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
+
+ index_rbio_pages(rbio);
+
+ /*
+ * 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.
+ */
+ 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++)
+ generate_pq_vertical(rbio, sectornr);
+
+ bio_list_init(&bio_list);
+ ret = rmw_assemble_write_bios(rbio, &bio_list);
+ if (ret < 0)
+ goto out;
+
+ /* We should have at least one bio assembled. */
+ ASSERT(bio_list_size(&bio_list));
+ submit_write_bios(rbio, &bio_list);
+ wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
+
+ /* We may have more errors than our tolerance during the read. */
+ for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
+ int found_errors;
+
+ found_errors = get_rbio_veritical_errors(rbio, sectornr, NULL, NULL);
+ if (found_errors > rbio->bioc->max_errors) {
+ ret = -EIO;
+ break;
+ }
+ }
+out:
+ rbio_orig_end_io(rbio, errno_to_blk_status(ret));
+}
+
+static void rmw_rbio_work(struct work_struct *work)
+{
+ struct btrfs_raid_bio *rbio;
+
+ rbio = container_of(work, struct btrfs_raid_bio, work);
+ if (lock_stripe_add(rbio) == 0)
+ rmw_rbio(rbio);
+}
+
+static void rmw_rbio_work_locked(struct work_struct *work)
+{
+ rmw_rbio(container_of(work, struct btrfs_raid_bio, work));
+}
+
+/*
+ * 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;
+}
+
+/*
+ * 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 int finish_parity_scrub(struct btrfs_raid_bio *rbio)
+{
+ 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;
+ 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();
+
+ /*
+ * Replace is running and our P/Q stripe is being replaced, then we
+ * need to duplicate the final write to replace target.
+ */
+ if (bioc->replace_nr_stripes && bioc->replace_stripe_src == 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);
+
+ p_sector.page = alloc_page(GFP_NOFS);
+ if (!p_sector.page)
+ return -ENOMEM;
+ 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;
+ return -ENOMEM;
+ }
+ q_sector.pgoff = 0;
+ q_sector.uptodate = 1;
+ pointers[rbio->real_stripes - 1] = kmap_local_page(q_sector.page);
+ }
+
+ bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
+
+ /* 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;
+ }
+
+ /*
+ * 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;
+
+ /*
+ * Replace is running and our parity stripe needs to be duplicated to
+ * the target device. Check we have a valid source stripe number.
+ */
+ ASSERT(rbio->bioc->replace_stripe_src >= 0);
+ 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,
+ rbio->real_stripes,
+ sectornr, REQ_OP_WRITE);
+ if (ret)
+ goto cleanup;
+ }
+
+submit_write:
+ submit_write_bios(rbio, &bio_list);
+ return 0;
+
+cleanup:
+ bio_list_put(&bio_list);
+ return ret;
+}
+
+static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
+{
+ if (stripe >= 0 && stripe < rbio->nr_data)
+ return 1;
+ return 0;
+}
+
+static int recover_scrub_rbio(struct btrfs_raid_bio *rbio)
+{
+ void **pointers = NULL;
+ void **unmap_array = NULL;
+ int sector_nr;
+ int ret = 0;
+
+ /*
+ * @pointers array stores the pointer for each sector.
+ *
+ * @unmap_array stores copy of pointers that does not get reordered
+ * during reconstruction so that kunmap_local works.
+ */
+ pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
+ unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
+ if (!pointers || !unmap_array) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
+ int dfail = 0, failp = -1;
+ int faila;
+ int failb;
+ int found_errors;
+
+ found_errors = get_rbio_veritical_errors(rbio, sector_nr,
+ &faila, &failb);
+ if (found_errors > rbio->bioc->max_errors) {
+ ret = -EIO;
+ goto out;
+ }
+ if (found_errors == 0)
+ continue;
+
+ /* We should have at least one error here. */
+ ASSERT(faila >= 0 || failb >= 0);
+
+ if (is_data_stripe(rbio, faila))
+ dfail++;
+ else if (is_parity_stripe(faila))
+ failp = faila;
+
+ if (is_data_stripe(rbio, failb))
+ dfail++;
+ else if (is_parity_stripe(failb))
+ failp = 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) {
+ ret = -EIO;
+ goto out;
+ }
+ /*
+ * If all data is good, only parity is correctly, just repair
+ * the parity, no need to recover data stripes.
+ */
+ if (dfail == 0)
+ continue;
+
+ /*
+ * 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) {
+ ret = -EIO;
+ goto out;
+ }
+
+ ret = recover_vertical(rbio, sector_nr, pointers, unmap_array);
+ if (ret < 0)
+ goto out;
+ }
+out:
+ kfree(pointers);
+ kfree(unmap_array);
+ return ret;
+}
+
+static int scrub_assemble_read_bios(struct btrfs_raid_bio *rbio)
+{
+ struct bio_list bio_list = BIO_EMPTY_LIST;
+ int total_sector_nr;
+ int ret = 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) {
+ bio_list_put(&bio_list);
+ return ret;
+ }
+ }
+
+ submit_read_wait_bio_list(rbio, &bio_list);
+ return 0;
+}
+
+static void scrub_rbio(struct btrfs_raid_bio *rbio)
+{
+ int sector_nr;
+ int ret;
+
+ ret = alloc_rbio_essential_pages(rbio);
+ if (ret)
+ goto out;
+
+ bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
+
+ ret = scrub_assemble_read_bios(rbio);
+ if (ret < 0)
+ goto out;
+
+ /* We may have some failures, recover the failed sectors first. */
+ ret = recover_scrub_rbio(rbio);
+ if (ret < 0)
+ goto out;
+
+ /*
+ * We have every sector properly prepared. Can finish the scrub
+ * and writeback the good content.
+ */
+ ret = finish_parity_scrub(rbio);
+ wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
+ for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
+ int found_errors;
+
+ found_errors = get_rbio_veritical_errors(rbio, sector_nr, NULL, NULL);
+ if (found_errors > rbio->bioc->max_errors) {
+ ret = -EIO;
+ break;
+ }
+ }
+out:
+ rbio_orig_end_io(rbio, errno_to_blk_status(ret));
+}
+
+static void scrub_rbio_work_locked(struct work_struct *work)
+{
+ scrub_rbio(container_of(work, struct btrfs_raid_bio, work));
+}
+
+void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
+{
+ if (!lock_stripe_add(rbio))
+ start_async_work(rbio, scrub_rbio_work_locked);
+}
+
+/*
+ * This is for scrub call sites where we already have correct data contents.
+ * This allows us to avoid reading data stripes again.
+ *
+ * Unfortunately here we have to do page copy, other than reusing the pages.
+ * This is due to the fact rbio has its own page management for its cache.
+ */
+void raid56_parity_cache_data_pages(struct btrfs_raid_bio *rbio,
+ struct page **data_pages, u64 data_logical)
+{
+ const u64 offset_in_full_stripe = data_logical -
+ rbio->bioc->full_stripe_logical;
+ const int page_index = offset_in_full_stripe >> PAGE_SHIFT;
+ const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
+ const u32 sectors_per_page = PAGE_SIZE / sectorsize;
+ int ret;
+
+ /*
+ * If we hit ENOMEM temporarily, but later at
+ * raid56_parity_submit_scrub_rbio() time it succeeded, we just do
+ * the extra read, not a big deal.
+ *
+ * If we hit ENOMEM later at raid56_parity_submit_scrub_rbio() time,
+ * the bio would got proper error number set.
+ */
+ ret = alloc_rbio_data_pages(rbio);
+ if (ret < 0)
+ return;
+
+ /* data_logical must be at stripe boundary and inside the full stripe. */
+ ASSERT(IS_ALIGNED(offset_in_full_stripe, BTRFS_STRIPE_LEN));
+ ASSERT(offset_in_full_stripe < (rbio->nr_data << BTRFS_STRIPE_LEN_SHIFT));
+
+ for (int page_nr = 0; page_nr < (BTRFS_STRIPE_LEN >> PAGE_SHIFT); page_nr++) {
+ struct page *dst = rbio->stripe_pages[page_nr + page_index];
+ struct page *src = data_pages[page_nr];
+
+ memcpy_page(dst, 0, src, 0, PAGE_SIZE);
+ for (int sector_nr = sectors_per_page * page_index;
+ sector_nr < sectors_per_page * (page_index + 1);
+ sector_nr++)
+ rbio->stripe_sectors[sector_nr].uptodate = true;
+ }
+}