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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.
#ifndef BTRFS_RAID56_H
#define BTRFS_RAID56_H
#include <linux/types.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/bio.h>
#include <linux/refcount.h>
#include <linux/workqueue.h>
#include "volumes.h"
struct page;
struct sector_ptr;
struct btrfs_fs_info;
enum btrfs_rbio_ops {
struct btrfs_raid_bio {
struct btrfs_io_context *bioc;
* While we're doing RMW on a stripe we put it into a hash table so we
* can lock the stripe and merge more rbios into it.
struct list_head hash_list;
/* LRU list for the stripe cache */
struct list_head stripe_cache;
/* For scheduling work in the helper threads */
struct work_struct work;
* bio_list and bio_list_lock are used to add more bios into the stripe
* in hopes of avoiding the full RMW
struct bio_list bio_list;
spinlock_t bio_list_lock;
* Also protected by the bio_list_lock, the plug list is used by the
* plugging code to collect partial bios while plugged. The stripe
* locking code also uses it to hand off the stripe lock to the next
* pending IO.
struct list_head plug_list;
/* Flags that tell us if it is safe to merge with this bio. */
unsigned long flags;
* Set if we're doing a parity rebuild for a read from higher up, which
* is handled differently from a parity rebuild as part of RMW.
enum btrfs_rbio_ops operation;
/* How many pages there are for the full stripe including P/Q */
u16 nr_pages;
/* How many sectors there are for the full stripe including P/Q */
u16 nr_sectors;
/* Number of data stripes (no p/q) */
u8 nr_data;
/* Number of all stripes (including P/Q) */
u8 real_stripes;
/* How many pages there are for each stripe */
u8 stripe_npages;
/* How many sectors there are for each stripe */
u8 stripe_nsectors;
/* Stripe number that we're scrubbing */
u8 scrubp;
* Size of all the bios in the bio_list. This helps us decide if the
* rbio maps to a full stripe or not.
int bio_list_bytes;
refcount_t refs;
atomic_t stripes_pending;
wait_queue_head_t io_wait;
/* Bitmap to record which horizontal stripe has data */
unsigned long dbitmap;
/* Allocated with stripe_nsectors-many bits for finish_*() calls */
unsigned long finish_pbitmap;
* These are two arrays of pointers. We allocate the rbio big enough
* to hold them both and setup their locations when the rbio is
* allocated.
* Pointers to pages that we allocated for reading/writing stripes
* directly from the disk (including P/Q).
struct page **stripe_pages;
/* Pointers to the sectors in the bio_list, for faster lookup */
struct sector_ptr *bio_sectors;
* For subpage support, we need to map each sector to above
* stripe_pages.
struct sector_ptr *stripe_sectors;
/* Allocated with real_stripes-many pointers for finish_*() calls */
void **finish_pointers;
* The bitmap recording where IO errors happened.
* Each bit is corresponding to one sector in either bio_sectors[] or
* stripe_sectors[] array.
* The reason we don't use another bit in sector_ptr is, we have two
* arrays of sectors, and a lot of IO can use sectors in both arrays.
* Thus making it much harder to iterate.
unsigned long *error_bitmap;
* Checksum buffer if the rbio is for data. The buffer should cover
* all data sectors (excluding P/Q sectors).
u8 *csum_buf;
* Each bit represents if the corresponding sector has data csum found.
* Should only cover data sectors (excluding P/Q sectors).
unsigned long *csum_bitmap;
* For trace event usage only. Records useful debug info for each bio submitted
* by RAID56 to each physical device.
* No matter signed or not, (-1) is always the one indicating we can not grab
* the proper stripe number.
struct raid56_bio_trace_info {
u64 devid;
/* The offset inside the stripe. (<= STRIPE_LEN) */
u32 offset;
* Stripe number.
* 0 is the first data stripe, and nr_data for P stripe,
* nr_data + 1 for Q stripe.
* >= real_stripes for
u8 stripe_nr;
static inline int nr_data_stripes(const struct btrfs_chunk_map *map)
return map->num_stripes - btrfs_nr_parity_stripes(map->type);
static inline int nr_bioc_data_stripes(const struct btrfs_io_context *bioc)
return bioc->num_stripes - btrfs_nr_parity_stripes(bioc->map_type);
#define RAID5_P_STRIPE ((u64)-2)
#define RAID6_Q_STRIPE ((u64)-1)
#define is_parity_stripe(x) (((x) == RAID5_P_STRIPE) || \
((x) == RAID6_Q_STRIPE))
struct btrfs_device;
void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
int mirror_num);
void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc);
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);
void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio);
void raid56_parity_cache_data_pages(struct btrfs_raid_bio *rbio,
struct page **data_pages, u64 data_logical);
int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info);
void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info);