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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _RAID10_H
#define _RAID10_H
/* Note: raid10_info.rdev can be set to NULL asynchronously by
* raid10_remove_disk.
* There are three safe ways to access raid10_info.rdev.
* 1/ when holding mddev->reconfig_mutex
* 2/ when resync/recovery/reshape is known to be happening - i.e. in code
* that is called as part of performing resync/recovery/reshape.
* 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer
* and if it is non-NULL, increment rdev->nr_pending before dropping the
* RCU lock.
* When .rdev is set to NULL, the nr_pending count checked again and if it has
* been incremented, the pointer is put back in .rdev.
struct raid10_info {
struct md_rdev *rdev, *replacement;
sector_t head_position;
int recovery_disabled; /* matches
* mddev->recovery_disabled
* when we shouldn't try
* recovering this device.
struct r10conf {
struct mddev *mddev;
struct raid10_info *mirrors;
struct raid10_info *mirrors_new, *mirrors_old;
spinlock_t device_lock;
/* geometry */
struct geom {
int raid_disks;
int near_copies; /* number of copies laid out
* raid0 style */
int far_copies; /* number of copies laid out
* at large strides across drives
int far_offset; /* far_copies are offset by 1
* stripe instead of many
sector_t stride; /* distance between far copies.
* This is size / far_copies unless
* far_offset, in which case it is
* 1 stripe.
int far_set_size; /* The number of devices in a set,
* where a 'set' are devices that
* contain far/offset copies of
* each other.
int chunk_shift; /* shift from chunks to sectors */
sector_t chunk_mask;
} prev, geo;
int copies; /* near_copies * far_copies.
* must be <= raid_disks
sector_t dev_sectors; /* temp copy of
* mddev->dev_sectors */
sector_t reshape_progress;
sector_t reshape_safe;
unsigned long reshape_checkpoint;
sector_t offset_diff;
struct list_head retry_list;
/* A separate list of r1bio which just need raid_end_bio_io called.
* This mustn't happen for writes which had any errors if the superblock
* needs to be written.
struct list_head bio_end_io_list;
/* queue pending writes and submit them on unplug */
struct bio_list pending_bio_list;
int pending_count;
spinlock_t resync_lock;
atomic_t nr_pending;
int nr_waiting;
int nr_queued;
int barrier;
int array_freeze_pending;
sector_t next_resync;
int fullsync; /* set to 1 if a full sync is needed,
* (fresh device added).
* Cleared when a sync completes.
int have_replacement; /* There is at least one
* replacement device.
wait_queue_head_t wait_barrier;
mempool_t r10bio_pool;
mempool_t r10buf_pool;
struct page *tmppage;
struct bio_set bio_split;
/* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array.
struct md_thread *thread;
* Keep track of cluster resync window to send to other nodes.
sector_t cluster_sync_low;
sector_t cluster_sync_high;
* this is our 'private' RAID10 bio.
* it contains information about what kind of IO operations were started
* for this RAID10 operation, and about their status:
struct r10bio {
atomic_t remaining; /* 'have we finished' count,
* used from IRQ handlers
sector_t sector; /* virtual sector number */
int sectors;
unsigned long state;
struct mddev *mddev;
* original bio going to /dev/mdx
struct bio *master_bio;
* if the IO is in READ direction, then this is where we read
int read_slot;
struct list_head retry_list;
* if the IO is in WRITE direction, then multiple bios are used,
* one for each copy.
* When resyncing we also use one for each copy.
* When reconstructing, we use 2 bios, one for read, one for write.
* We choose the number when they are allocated.
* We sometimes need an extra bio to write to the replacement.
struct r10dev {
struct bio *bio;
union {
struct bio *repl_bio; /* used for resync and
* writes */
struct md_rdev *rdev; /* used for reads
* (read_slot >= 0) */
sector_t addr;
int devnum;
} devs[0];
/* bits for r10bio.state */
enum r10bio_state {
/* Set ReadError on bios that experience a read error
* so that raid10d knows what to do with them.
/* If a write for this request means we can clear some
* known-bad-block records, we set this flag.
/* During a reshape we might be performing IO on the
* 'previous' part of the array, in which case this
* flag is set
/* failfast devices did receive failfast requests. */