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linux/fs/btrfs/raid56.c
Qu Wenruo cb3450b7d7 btrfs: raid56: extract scrub read bio list assembly code into a helper 
Just like what we did for write/recovery, also extract the read bio
assembly code into a helper for scrub.

The difference between the three are:

- rmw_assemble_read_bios() only submit reads for missing sectors
  Thus it will skip cached sectors, but will also read sectors which
  is not covered by any full stripe. (For cache usage)

- recover_assemble_read_bios() reads every sector which has not failed

- scrub_assemble_read_bios() has extra check for vertical stripes
  It's mostly the same as rmw_assemble_read_bios(), but will skip
  sectors which is not covered by a vertical stripe.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-12-05 18:00:49 +01:00

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// 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"
/* 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 noinline void finish_rmw(struct btrfs_raid_bio *rbio);
static void rmw_rbio_work(struct work_struct *work);
static void rmw_rbio_work_locked(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 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 free_raid_bio_pointers(struct btrfs_raid_bio *rbio)
{
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->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;
}
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;
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;
}
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;
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, recover_rbio_work_locked);
else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
steal_rbio(rbio, next);
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_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 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;
/* 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);
if (!rbio->stripe_pages || !rbio->bio_sectors || !rbio->stripe_sectors ||
!rbio->finish_pointers) {
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;
rbio->faila = -1;
rbio->failb = -1;
refcount_set(&rbio->refs, 1);
atomic_set(&rbio->error, 0);
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;
}
/*
* 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;
}
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;
}
/* Generate PQ for one veritical 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)
{
struct bio *bio;
/* 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.
*/
atomic_set(&rbio->error, 0);
rbio->faila = -1;
rbio->failb = -1;
/*
* 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->num_tgtdevs))
return 0;
/* Make a copy for the replace target device. */
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 (!rbio->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 error;
}
return 0;
error:
while ((bio = bio_list_pop(bio_list)))
bio_put(bio);
return -EIO;
}
/*
* 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)
{
/* The total sector number inside the full stripe. */
/* Sector number inside a stripe. */
int sectornr;
struct bio_list bio_list;
struct bio *bio;
int ret;
bio_list_init(&bio_list);
/* 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++)
generate_pq_vertical(rbio, sectornr);
ret = rmw_assemble_write_bios(rbio, &bio_list);
if (ret < 0)
goto cleanup;
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 raid_wait_read_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))
wake_up(&rbio->io_wait);
}
static void submit_read_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_read_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);
}
}
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);
}
static int rmw_assemble_read_bios(struct btrfs_raid_bio *rbio,
struct bio_list *bio_list)
{
const int nr_data_sectors = rbio->stripe_nsectors * rbio->nr_data;
struct bio *bio;
int total_sector_nr;
int ret = 0;
ASSERT(bio_list_size(bio_list) == 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;
}
return 0;
cleanup:
while ((bio = bio_list_pop(bio_list)))
bio_put(bio);
return ret;
}
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->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))
goto queue_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;
}
queue_rbio:
/*
* Either we don't have any existing plug, or we're doing a full stripe,
* can queue the rmw work now.
*/
start_async_work(rbio, rmw_rbio_work);
return;
fail:
bio->bi_status = errno_to_blk_status(ret);
bio_endio(bio);
}
/*
* 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 void 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;
const int faila = rbio->faila;
const int failb = rbio->failb;
int stripe_nr;
/*
* 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;
/*
* 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 ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
(stripe_nr == faila || stripe_nr == failb)) {
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 (rbio->bioc->raid_map[failb] == RAID6_Q_STRIPE) {
if (rbio->bioc->raid_map[faila] ==
RAID5_P_STRIPE)
/*
* 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 (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). */
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 (rbio->faila >= 0) {
sector = rbio_stripe_sector(rbio, rbio->faila, sector_nr);
sector->uptodate = 1;
}
if (rbio->failb >= 0) {
sector = rbio_stripe_sector(rbio, 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]);
}
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;
}
/* Make sure faila and fail b are in order. */
if (rbio->faila >= 0 && rbio->failb >= 0 && rbio->faila > rbio->failb)
swap(rbio->faila, 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++)
recover_vertical(rbio, sectornr, pointers, unmap_array);
out:
kfree(pointers);
kfree(unmap_array);
return ret;
}
/*
* 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)
{
int ret;
ret = recover_sectors(rbio);
/*
* 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 (!ret && rbio->failb < 0)
cache_rbio_pages(rbio);
else
clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
rbio_orig_end_io(rbio, errno_to_blk_status(ret));
} else if (!ret) {
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, errno_to_blk_status(ret));
}
}
static int recover_assemble_read_bios(struct btrfs_raid_bio *rbio,
struct bio_list *bio_list)
{
struct bio *bio;
int total_sector_nr;
int ret = 0;
ASSERT(bio_list_size(bio_list) == 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 error;
}
return 0;
error:
while ((bio = bio_list_pop(bio_list)))
bio_put(bio);
return -EIO;
}
static int recover_rbio(struct btrfs_raid_bio *rbio)
{
struct bio_list bio_list;
struct bio *bio;
int ret;
/*
* Either we're doing recover for a read failure or degraded write,
* caller should have set faila/b correctly.
*/
ASSERT(rbio->faila >= 0 || rbio->failb >= 0);
bio_list_init(&bio_list);
/*
* Reset error to 0, as we will later increase error for missing
* devices.
*/
atomic_set(&rbio->error, 0);
/* 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);
ret = recover_assemble_read_bios(rbio, &bio_list);
if (ret < 0)
goto out;
submit_read_bios(rbio, &bio_list);
wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
/* We have more errors than our tolerance during the read. */
if (atomic_read(&rbio->error) > rbio->bioc->max_errors) {
ret = -EIO;
goto out;
}
ret = recover_sectors(rbio);
out:
while ((bio = bio_list_pop(&bio_list)))
bio_put(bio);
return ret;
}
static void recover_rbio_work(struct work_struct *work)
{
struct btrfs_raid_bio *rbio;
int ret;
rbio = container_of(work, struct btrfs_raid_bio, work);
ret = lock_stripe_add(rbio);
if (ret == 0) {
ret = recover_rbio(rbio);
rbio_orig_end_io(rbio, errno_to_blk_status(ret));
}
}
static void recover_rbio_work_locked(struct work_struct *work)
{
struct btrfs_raid_bio *rbio;
int ret;
rbio = container_of(work, struct btrfs_raid_bio, work);
ret = recover_rbio(rbio);
rbio_orig_end_io(rbio, errno_to_blk_status(ret));
}
/*
* 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);
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;
bio_endio(bio);
return;
}
/*
* 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--;
}
start_async_work(rbio, recover_rbio_work);
}
static int rmw_read_and_wait(struct btrfs_raid_bio *rbio)
{
struct bio_list bio_list;
struct bio *bio;
int ret;
bio_list_init(&bio_list);
atomic_set(&rbio->error, 0);
ret = rmw_assemble_read_bios(rbio, &bio_list);
if (ret < 0)
goto out;
submit_read_bios(rbio, &bio_list);
wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
return ret;
out:
while ((bio = bio_list_pop(&bio_list)))
bio_put(bio);
return ret;
}
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)
fail_bio_stripe(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_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);
}
}
static int 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)
return ret;
/* Full stripe write, can write the full stripe right now. */
if (rbio_is_full(rbio))
goto write;
/*
* 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)
return ret;
atomic_set(&rbio->error, 0);
index_rbio_pages(rbio);
ret = rmw_read_and_wait(rbio);
if (ret < 0)
return ret;
/* Too many read errors, beyond our tolerance. */
if (atomic_read(&rbio->error) > rbio->bioc->max_errors)
return ret;
/* Have read failures but under tolerance, needs recovery. */
if (rbio->faila >= 0 || rbio->failb >= 0) {
ret = recover_rbio(rbio);
if (ret < 0)
return ret;
}
write:
/*
* 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_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);
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)
return ret;
/* 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 have more errors than our tolerance during the read. */
if (atomic_read(&rbio->error) > rbio->bioc->max_errors)
ret = -EIO;
return ret;
}
static void rmw_rbio_work(struct work_struct *work)
{
struct btrfs_raid_bio *rbio;
int ret;
rbio = container_of(work, struct btrfs_raid_bio, work);
ret = lock_stripe_add(rbio);
if (ret == 0) {
ret = rmw_rbio(rbio);
rbio_orig_end_io(rbio, errno_to_blk_status(ret));
}
}
static void rmw_rbio_work_locked(struct work_struct *work)
{
struct btrfs_raid_bio *rbio;
int ret;
rbio = container_of(work, struct btrfs_raid_bio, work);
ret = rmw_rbio(rbio);
rbio_orig_end_io(rbio, errno_to_blk_status(ret));
}
/*
* 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 int scrub_assemble_read_bios(struct btrfs_raid_bio *rbio,
struct bio_list *bio_list)
{
struct bio *bio;
int total_sector_nr;
int ret = 0;
ASSERT(bio_list_size(bio_list) == 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 error;
}
return 0;
error:
while ((bio = bio_list_pop(bio_list)))
bio_put(bio);
return ret;
}
static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
{
int bios_to_read = 0;
struct bio_list bio_list;
int ret;
struct bio *bio;
bio_list_init(&bio_list);
ret = alloc_rbio_essential_pages(rbio);
if (ret)
goto cleanup;
atomic_set(&rbio->error, 0);
ret = scrub_assemble_read_bios(rbio, &bio_list);
if (ret < 0)
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)
{
start_async_work(rbio, recover_rbio_work);
}
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