[mirror_ubuntu-hirsute-kernel.git] / fs / btrfs / volumes.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 */

#ifndef BTRFS_VOLUMES_H
#define BTRFS_VOLUMES_H

#include <linux/bio.h>
#include <linux/sort.h>
#include <linux/btrfs.h>
#include "async-thread.h"

extern struct mutex uuid_mutex;

#define BTRFS_STRIPE_LEN	SZ_64K

struct buffer_head;
struct btrfs_pending_bios {
	struct bio *head;
	struct bio *tail;
};

/*
 * Use sequence counter to get consistent device stat data on
 * 32-bit processors.
 */
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
#include <linux/seqlock.h>
#define __BTRFS_NEED_DEVICE_DATA_ORDERED
#define btrfs_device_data_ordered_init(device)	\
	seqcount_init(&device->data_seqcount)
#else
#define btrfs_device_data_ordered_init(device) do { } while (0)
#endif

#define BTRFS_DEV_STATE_WRITEABLE	(0)
#define BTRFS_DEV_STATE_IN_FS_METADATA	(1)
#define BTRFS_DEV_STATE_MISSING		(2)
#define BTRFS_DEV_STATE_REPLACE_TGT	(3)
#define BTRFS_DEV_STATE_FLUSH_SENT	(4)

struct btrfs_device {
	struct list_head dev_list;
	struct list_head dev_alloc_list;
	struct btrfs_fs_devices *fs_devices;
	struct btrfs_fs_info *fs_info;

	struct rcu_string *name;

	u64 generation;

	spinlock_t io_lock ____cacheline_aligned;
	int running_pending;
	/* regular prio bios */
	struct btrfs_pending_bios pending_bios;
	/* sync bios */
	struct btrfs_pending_bios pending_sync_bios;

	struct block_device *bdev;

	/* the mode sent to blkdev_get */
	fmode_t mode;

	unsigned long dev_state;
	blk_status_t last_flush_error;
	int flush_bio_sent;

#ifdef __BTRFS_NEED_DEVICE_DATA_ORDERED
	seqcount_t data_seqcount;
#endif

	/* the internal btrfs device id */
	u64 devid;

	/* size of the device in memory */
	u64 total_bytes;

	/* size of the device on disk */
	u64 disk_total_bytes;

	/* bytes used */
	u64 bytes_used;

	/* optimal io alignment for this device */
	u32 io_align;

	/* optimal io width for this device */
	u32 io_width;
	/* type and info about this device */
	u64 type;

	/* minimal io size for this device */
	u32 sector_size;

	/* physical drive uuid (or lvm uuid) */
	u8 uuid[BTRFS_UUID_SIZE];

	/*
	 * size of the device on the current transaction
	 *
	 * This variant is update when committing the transaction,
	 * and protected by device_list_mutex
	 */
	u64 commit_total_bytes;

	/* bytes used on the current transaction */
	u64 commit_bytes_used;
	/*
	 * used to manage the device which is resized
	 *
	 * It is protected by chunk_lock.
	 */
	struct list_head resized_list;

	/* for sending down flush barriers */
	struct bio *flush_bio;
	struct completion flush_wait;

	/* per-device scrub information */
	struct scrub_ctx *scrub_ctx;

	struct btrfs_work work;
	struct rcu_head rcu;

	/* readahead state */
	atomic_t reada_in_flight;
	u64 reada_next;
	struct reada_zone *reada_curr_zone;
	struct radix_tree_root reada_zones;
	struct radix_tree_root reada_extents;

	/* disk I/O failure stats. For detailed description refer to
	 * enum btrfs_dev_stat_values in ioctl.h */
	int dev_stats_valid;

	/* Counter to record the change of device stats */
	atomic_t dev_stats_ccnt;
	atomic_t dev_stat_values[BTRFS_DEV_STAT_VALUES_MAX];
};

/*
 * If we read those variants at the context of their own lock, we needn't
 * use the following helpers, reading them directly is safe.
 */
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
#define BTRFS_DEVICE_GETSET_FUNCS(name)					\
static inline u64							\
btrfs_device_get_##name(const struct btrfs_device *dev)			\
{									\
	u64 size;							\
	unsigned int seq;						\
									\
	do {								\
		seq = read_seqcount_begin(&dev->data_seqcount);		\
		size = dev->name;					\
	} while (read_seqcount_retry(&dev->data_seqcount, seq));	\
	return size;							\
}									\
									\
static inline void							\
btrfs_device_set_##name(struct btrfs_device *dev, u64 size)		\
{									\
	preempt_disable();						\
	write_seqcount_begin(&dev->data_seqcount);			\
	dev->name = size;						\
	write_seqcount_end(&dev->data_seqcount);			\
	preempt_enable();						\
}
#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
#define BTRFS_DEVICE_GETSET_FUNCS(name)					\
static inline u64							\
btrfs_device_get_##name(const struct btrfs_device *dev)			\
{									\
	u64 size;							\
									\
	preempt_disable();						\
	size = dev->name;						\
	preempt_enable();						\
	return size;							\
}									\
									\
static inline void							\
btrfs_device_set_##name(struct btrfs_device *dev, u64 size)		\
{									\
	preempt_disable();						\
	dev->name = size;						\
	preempt_enable();						\
}
#else
#define BTRFS_DEVICE_GETSET_FUNCS(name)					\
static inline u64							\
btrfs_device_get_##name(const struct btrfs_device *dev)			\
{									\
	return dev->name;						\
}									\
									\
static inline void							\
btrfs_device_set_##name(struct btrfs_device *dev, u64 size)		\
{									\
	dev->name = size;						\
}
#endif

BTRFS_DEVICE_GETSET_FUNCS(total_bytes);
BTRFS_DEVICE_GETSET_FUNCS(disk_total_bytes);
BTRFS_DEVICE_GETSET_FUNCS(bytes_used);

struct btrfs_fs_devices {
	u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
	struct list_head fs_list;

	u64 num_devices;
	u64 open_devices;
	u64 rw_devices;
	u64 missing_devices;
	u64 total_rw_bytes;
	u64 total_devices;
	struct block_device *latest_bdev;

	/* all of the devices in the FS, protected by a mutex
	 * so we can safely walk it to write out the supers without
	 * worrying about add/remove by the multi-device code.
	 * Scrubbing super can kick off supers writing by holding
	 * this mutex lock.
	 */
	struct mutex device_list_mutex;
	struct list_head devices;

	struct list_head resized_devices;
	/* devices not currently being allocated */
	struct list_head alloc_list;

	struct btrfs_fs_devices *seed;
	int seeding;

	int opened;

	/* set when we find or add a device that doesn't have the
	 * nonrot flag set
	 */
	int rotating;

	struct btrfs_fs_info *fs_info;
	/* sysfs kobjects */
	struct kobject fsid_kobj;
	struct kobject *device_dir_kobj;
	struct completion kobj_unregister;
};

#define BTRFS_BIO_INLINE_CSUM_SIZE	64

/*
 * we need the mirror number and stripe index to be passed around
 * the call chain while we are processing end_io (especially errors).
 * Really, what we need is a btrfs_bio structure that has this info
 * and is properly sized with its stripe array, but we're not there
 * quite yet.  We have our own btrfs bioset, and all of the bios
 * we allocate are actually btrfs_io_bios.  We'll cram as much of
 * struct btrfs_bio as we can into this over time.
 */
typedef void (btrfs_io_bio_end_io_t) (struct btrfs_io_bio *bio, int err);
struct btrfs_io_bio {
	unsigned int mirror_num;
	unsigned int stripe_index;
	u64 logical;
	u8 *csum;
	u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
	u8 *csum_allocated;
	btrfs_io_bio_end_io_t *end_io;
	struct bvec_iter iter;
	/*
	 * This member must come last, bio_alloc_bioset will allocate enough
	 * bytes for entire btrfs_io_bio but relies on bio being last.
	 */
	struct bio bio;
};

static inline struct btrfs_io_bio *btrfs_io_bio(struct bio *bio)
{
	return container_of(bio, struct btrfs_io_bio, bio);
}

struct btrfs_bio_stripe {
	struct btrfs_device *dev;
	u64 physical;
	u64 length; /* only used for discard mappings */
};

struct btrfs_bio;
typedef void (btrfs_bio_end_io_t) (struct btrfs_bio *bio, int err);

struct btrfs_bio {
	refcount_t refs;
	atomic_t stripes_pending;
	struct btrfs_fs_info *fs_info;
	u64 map_type; /* get from map_lookup->type */
	bio_end_io_t *end_io;
	struct bio *orig_bio;
	unsigned long flags;
	void *private;
	atomic_t error;
	int max_errors;
	int num_stripes;
	int mirror_num;
	int num_tgtdevs;
	int *tgtdev_map;
	/*
	 * logical block numbers for the start of each stripe
	 * The last one or two are p/q.  These are sorted,
	 * so raid_map[0] is the start of our full stripe
	 */
	u64 *raid_map;
	struct btrfs_bio_stripe stripes[];
};

struct btrfs_device_info {
	struct btrfs_device *dev;
	u64 dev_offset;
	u64 max_avail;
	u64 total_avail;
};

struct btrfs_raid_attr {
	int sub_stripes;	/* sub_stripes info for map */
	int dev_stripes;	/* stripes per dev */
	int devs_max;		/* max devs to use */
	int devs_min;		/* min devs needed */
	int tolerated_failures; /* max tolerated fail devs */
	int devs_increment;	/* ndevs has to be a multiple of this */
	int ncopies;		/* how many copies to data has */
	int mindev_error;	/* error code if min devs requisite is unmet */
	const char raid_name[8]; /* name of the raid */
	u64 bg_flag;		/* block group flag of the raid */
};

extern const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES];

struct map_lookup {
	u64 type;
	int io_align;
	int io_width;
	u64 stripe_len;
	int num_stripes;
	int sub_stripes;
	struct btrfs_bio_stripe stripes[];
};

#define map_lookup_size(n) (sizeof(struct map_lookup) + \
			    (sizeof(struct btrfs_bio_stripe) * (n)))

struct btrfs_balance_args;
struct btrfs_balance_progress;
struct btrfs_balance_control {
	struct btrfs_balance_args data;
	struct btrfs_balance_args meta;
	struct btrfs_balance_args sys;

	u64 flags;

	struct btrfs_balance_progress stat;
};

enum btrfs_map_op {
	BTRFS_MAP_READ,
	BTRFS_MAP_WRITE,
	BTRFS_MAP_DISCARD,
	BTRFS_MAP_GET_READ_MIRRORS,
};

static inline enum btrfs_map_op btrfs_op(struct bio *bio)
{
	switch (bio_op(bio)) {
	case REQ_OP_DISCARD:
		return BTRFS_MAP_DISCARD;
	case REQ_OP_WRITE:
		return BTRFS_MAP_WRITE;
	default:
		WARN_ON_ONCE(1);
	case REQ_OP_READ:
		return BTRFS_MAP_READ;
	}
}

int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
				   u64 end, u64 *length);
void btrfs_get_bbio(struct btrfs_bio *bbio);
void btrfs_put_bbio(struct btrfs_bio *bbio);
int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
		    u64 logical, u64 *length,
		    struct btrfs_bio **bbio_ret, int mirror_num);
int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
		     u64 logical, u64 *length,
		     struct btrfs_bio **bbio_ret);
int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
		     u64 physical, u64 **logical, int *naddrs, int *stripe_len);
int btrfs_read_sys_array(struct btrfs_fs_info *fs_info);
int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info);
int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
		      struct btrfs_fs_info *fs_info, u64 type);
void btrfs_mapping_init(struct btrfs_mapping_tree *tree);
void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree);
blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
			   int mirror_num, int async_submit);
int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
		       fmode_t flags, void *holder);
int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
			  struct btrfs_fs_devices **fs_devices_ret);
int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step);
void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,
		struct btrfs_device *device, struct btrfs_device *this_dev);
int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
					 const char *device_path,
					 struct btrfs_device **device);
int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
					 const char *devpath,
					 struct btrfs_device **device);
struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
					const u64 *devid,
					const u8 *uuid);
void btrfs_free_device(struct btrfs_device *device);
int btrfs_rm_device(struct btrfs_fs_info *fs_info,
		    const char *device_path, u64 devid);
void __exit btrfs_cleanup_fs_uuids(void);
int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len);
int btrfs_grow_device(struct btrfs_trans_handle *trans,
		      struct btrfs_device *device, u64 new_size);
struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
				       u8 *uuid, u8 *fsid);
int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *path);
int btrfs_balance(struct btrfs_fs_info *fs_info,
		  struct btrfs_balance_control *bctl,
		  struct btrfs_ioctl_balance_args *bargs);
int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info);
int btrfs_recover_balance(struct btrfs_fs_info *fs_info);
int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info);
int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info);
int btrfs_chunk_readonly(struct btrfs_fs_info *fs_info, u64 chunk_offset);
int find_free_dev_extent_start(struct btrfs_transaction *transaction,
			 struct btrfs_device *device, u64 num_bytes,
			 u64 search_start, u64 *start, u64 *max_avail);
int find_free_dev_extent(struct btrfs_trans_handle *trans,
			 struct btrfs_device *device, u64 num_bytes,
			 u64 *start, u64 *max_avail);
void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index);
int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info,
			struct btrfs_ioctl_get_dev_stats *stats);
void btrfs_init_devices_late(struct btrfs_fs_info *fs_info);
int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info);
int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
			struct btrfs_fs_info *fs_info);
void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
					struct btrfs_device *srcdev);
void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
				      struct btrfs_device *srcdev);
void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
				      struct btrfs_device *tgtdev);
void btrfs_scratch_superblocks(struct block_device *bdev, const char *device_path);
int btrfs_is_parity_mirror(struct btrfs_fs_info *fs_info,
			   u64 logical, u64 len);
unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
				    u64 logical);
int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
				struct btrfs_fs_info *fs_info,
				u64 chunk_offset, u64 chunk_size);
int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
		       struct btrfs_fs_info *fs_info, u64 chunk_offset);

static inline void btrfs_dev_stat_inc(struct btrfs_device *dev,
				      int index)
{
	atomic_inc(dev->dev_stat_values + index);
	/*
	 * This memory barrier orders stores updating statistics before stores
	 * updating dev_stats_ccnt.
	 *
	 * It pairs with smp_rmb() in btrfs_run_dev_stats().
	 */
	smp_mb__before_atomic();
	atomic_inc(&dev->dev_stats_ccnt);
}

static inline int btrfs_dev_stat_read(struct btrfs_device *dev,
				      int index)
{
	return atomic_read(dev->dev_stat_values + index);
}

static inline int btrfs_dev_stat_read_and_reset(struct btrfs_device *dev,
						int index)
{
	int ret;

	ret = atomic_xchg(dev->dev_stat_values + index, 0);
	/*
	 * atomic_xchg implies a full memory barriers as per atomic_t.txt:
	 * - RMW operations that have a return value are fully ordered;
	 *
	 * This implicit memory barriers is paired with the smp_rmb in
	 * btrfs_run_dev_stats
	 */
	atomic_inc(&dev->dev_stats_ccnt);
	return ret;
}

static inline void btrfs_dev_stat_set(struct btrfs_device *dev,
				      int index, unsigned long val)
{
	atomic_set(dev->dev_stat_values + index, val);
	/*
	 * This memory barrier orders stores updating statistics before stores
	 * updating dev_stats_ccnt.
	 *
	 * It pairs with smp_rmb() in btrfs_run_dev_stats().
	 */
	smp_mb__before_atomic();
	atomic_inc(&dev->dev_stats_ccnt);
}

static inline void btrfs_dev_stat_reset(struct btrfs_device *dev,
					int index)
{
	btrfs_dev_stat_set(dev, index, 0);
}

/*
 * Convert block group flags (BTRFS_BLOCK_GROUP_*) to btrfs_raid_types, which
 * can be used as index to access btrfs_raid_array[].
 */
static inline enum btrfs_raid_types btrfs_bg_flags_to_raid_index(u64 flags)
{
	if (flags & BTRFS_BLOCK_GROUP_RAID10)
		return BTRFS_RAID_RAID10;
	else if (flags & BTRFS_BLOCK_GROUP_RAID1)
		return BTRFS_RAID_RAID1;
	else if (flags & BTRFS_BLOCK_GROUP_DUP)
		return BTRFS_RAID_DUP;
	else if (flags & BTRFS_BLOCK_GROUP_RAID0)
		return BTRFS_RAID_RAID0;
	else if (flags & BTRFS_BLOCK_GROUP_RAID5)
		return BTRFS_RAID_RAID5;
	else if (flags & BTRFS_BLOCK_GROUP_RAID6)
		return BTRFS_RAID_RAID6;

	return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
}

const char *get_raid_name(enum btrfs_raid_types type);

void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info);
void btrfs_update_commit_device_bytes_used(struct btrfs_transaction *trans);

struct list_head *btrfs_get_fs_uuids(void);
void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info);
void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info);
bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
					struct btrfs_device *failing_dev);

#endif
Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	/*
	3	* Copyright (C) 2007 Oracle. All rights reserved.
	4	*/
	5
	6	#ifndef BTRFS_VOLUMES_H
	7	#define BTRFS_VOLUMES_H
	8
	9	#include <linux/bio.h>
	10	#include <linux/sort.h>
	11	#include <linux/btrfs.h>
	12	#include "async-thread.h"
	13
	14	extern struct mutex uuid_mutex;
	15
	16	#define BTRFS_STRIPE_LEN SZ_64K
	17
	18	struct buffer_head;
	19	struct btrfs_pending_bios {
	20	struct bio *head;
	21	struct bio *tail;
	22	};
	23
	24	/*
	25	* Use sequence counter to get consistent device stat data on
	26	* 32-bit processors.
	27	*/
	28	#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
	29	#include <linux/seqlock.h>
	30	#define __BTRFS_NEED_DEVICE_DATA_ORDERED
	31	#define btrfs_device_data_ordered_init(device) \
	32	seqcount_init(&device->data_seqcount)
	33	#else
	34	#define btrfs_device_data_ordered_init(device) do { } while (0)
	35	#endif
	36
	37	#define BTRFS_DEV_STATE_WRITEABLE (0)
	38	#define BTRFS_DEV_STATE_IN_FS_METADATA (1)
	39	#define BTRFS_DEV_STATE_MISSING (2)
	40	#define BTRFS_DEV_STATE_REPLACE_TGT (3)
	41	#define BTRFS_DEV_STATE_FLUSH_SENT (4)
	42
	43	struct btrfs_device {
	44	struct list_head dev_list;
	45	struct list_head dev_alloc_list;
	46	struct btrfs_fs_devices *fs_devices;
	47	struct btrfs_fs_info *fs_info;
	48
	49	struct rcu_string *name;
	50
	51	u64 generation;
	52
	53	spinlock_t io_lock ____cacheline_aligned;
	54	int running_pending;
	55	/* regular prio bios */
	56	struct btrfs_pending_bios pending_bios;
	57	/* sync bios */
	58	struct btrfs_pending_bios pending_sync_bios;
	59
	60	struct block_device *bdev;
	61
	62	/* the mode sent to blkdev_get */
	63	fmode_t mode;
	64
	65	unsigned long dev_state;
	66	blk_status_t last_flush_error;
	67	int flush_bio_sent;
	68
	69	#ifdef __BTRFS_NEED_DEVICE_DATA_ORDERED
	70	seqcount_t data_seqcount;
	71	#endif
	72
	73	/* the internal btrfs device id */
	74	u64 devid;
	75
	76	/* size of the device in memory */
	77	u64 total_bytes;
	78
	79	/* size of the device on disk */
	80	u64 disk_total_bytes;
	81
	82	/* bytes used */
	83	u64 bytes_used;
	84
	85	/* optimal io alignment for this device */
	86	u32 io_align;
	87
	88	/* optimal io width for this device */
	89	u32 io_width;
	90	/* type and info about this device */
	91	u64 type;
	92
	93	/* minimal io size for this device */
	94	u32 sector_size;
	95
	96	/* physical drive uuid (or lvm uuid) */
	97	u8 uuid[BTRFS_UUID_SIZE];
	98
	99	/*
	100	* size of the device on the current transaction
	101	*
	102	* This variant is update when committing the transaction,
	103	* and protected by device_list_mutex
	104	*/
	105	u64 commit_total_bytes;
	106
	107	/* bytes used on the current transaction */
	108	u64 commit_bytes_used;
	109	/*
	110	* used to manage the device which is resized
	111	*
	112	* It is protected by chunk_lock.
	113	*/
	114	struct list_head resized_list;
	115
	116	/* for sending down flush barriers */
	117	struct bio *flush_bio;
	118	struct completion flush_wait;
	119
	120	/* per-device scrub information */
	121	struct scrub_ctx *scrub_ctx;
	122
	123	struct btrfs_work work;
	124	struct rcu_head rcu;
	125
	126	/* readahead state */
	127	atomic_t reada_in_flight;
	128	u64 reada_next;
	129	struct reada_zone *reada_curr_zone;
	130	struct radix_tree_root reada_zones;
	131	struct radix_tree_root reada_extents;
	132
	133	/* disk I/O failure stats. For detailed description refer to
	134	* enum btrfs_dev_stat_values in ioctl.h */
	135	int dev_stats_valid;
	136
	137	/* Counter to record the change of device stats */
	138	atomic_t dev_stats_ccnt;
	139	atomic_t dev_stat_values[BTRFS_DEV_STAT_VALUES_MAX];
	140	};
	141
	142	/*
	143	* If we read those variants at the context of their own lock, we needn't
	144	* use the following helpers, reading them directly is safe.
	145	*/
	146	#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
	147	#define BTRFS_DEVICE_GETSET_FUNCS(name) \
	148	static inline u64 \
	149	btrfs_device_get_##name(const struct btrfs_device *dev) \
	150	{ \
	151	u64 size; \
	152	unsigned int seq; \
	153	\
	154	do { \
	155	seq = read_seqcount_begin(&dev->data_seqcount); \
	156	size = dev->name; \
	157	} while (read_seqcount_retry(&dev->data_seqcount, seq)); \
	158	return size; \
	159	} \
	160	\
	161	static inline void \
	162	btrfs_device_set_##name(struct btrfs_device *dev, u64 size) \
	163	{ \
	164	preempt_disable(); \
	165	write_seqcount_begin(&dev->data_seqcount); \
	166	dev->name = size; \
	167	write_seqcount_end(&dev->data_seqcount); \
	168	preempt_enable(); \
	169	}
	170	#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
	171	#define BTRFS_DEVICE_GETSET_FUNCS(name) \
	172	static inline u64 \
	173	btrfs_device_get_##name(const struct btrfs_device *dev) \
	174	{ \
	175	u64 size; \
	176	\
	177	preempt_disable(); \
	178	size = dev->name; \
	179	preempt_enable(); \
	180	return size; \
	181	} \
	182	\
	183	static inline void \
	184	btrfs_device_set_##name(struct btrfs_device *dev, u64 size) \
	185	{ \
	186	preempt_disable(); \
	187	dev->name = size; \
	188	preempt_enable(); \
	189	}
	190	#else
	191	#define BTRFS_DEVICE_GETSET_FUNCS(name) \
	192	static inline u64 \
	193	btrfs_device_get_##name(const struct btrfs_device *dev) \
	194	{ \
	195	return dev->name; \
	196	} \
	197	\
	198	static inline void \
	199	btrfs_device_set_##name(struct btrfs_device *dev, u64 size) \
	200	{ \
	201	dev->name = size; \
	202	}
	203	#endif
	204
	205	BTRFS_DEVICE_GETSET_FUNCS(total_bytes);
	206	BTRFS_DEVICE_GETSET_FUNCS(disk_total_bytes);
	207	BTRFS_DEVICE_GETSET_FUNCS(bytes_used);
	208
	209	struct btrfs_fs_devices {
	210	u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
	211	struct list_head fs_list;
	212
	213	u64 num_devices;
	214	u64 open_devices;
	215	u64 rw_devices;
	216	u64 missing_devices;
	217	u64 total_rw_bytes;
	218	u64 total_devices;
	219	struct block_device *latest_bdev;
	220
	221	/* all of the devices in the FS, protected by a mutex
	222	* so we can safely walk it to write out the supers without
	223	* worrying about add/remove by the multi-device code.
	224	* Scrubbing super can kick off supers writing by holding
	225	* this mutex lock.
	226	*/
	227	struct mutex device_list_mutex;
	228	struct list_head devices;
	229
	230	struct list_head resized_devices;
	231	/* devices not currently being allocated */
	232	struct list_head alloc_list;
	233
	234	struct btrfs_fs_devices *seed;
	235	int seeding;
	236
	237	int opened;
	238
	239	/* set when we find or add a device that doesn't have the
	240	* nonrot flag set
	241	*/
	242	int rotating;
	243
	244	struct btrfs_fs_info *fs_info;
	245	/* sysfs kobjects */
	246	struct kobject fsid_kobj;
	247	struct kobject *device_dir_kobj;
	248	struct completion kobj_unregister;
	249	};
	250
	251	#define BTRFS_BIO_INLINE_CSUM_SIZE 64
	252
	253	/*
	254	* we need the mirror number and stripe index to be passed around
	255	* the call chain while we are processing end_io (especially errors).
	256	* Really, what we need is a btrfs_bio structure that has this info
	257	* and is properly sized with its stripe array, but we're not there
	258	* quite yet. We have our own btrfs bioset, and all of the bios
	259	* we allocate are actually btrfs_io_bios. We'll cram as much of
	260	* struct btrfs_bio as we can into this over time.
	261	*/
	262	typedef void (btrfs_io_bio_end_io_t) (struct btrfs_io_bio *bio, int err);
	263	struct btrfs_io_bio {
	264	unsigned int mirror_num;
	265	unsigned int stripe_index;
	266	u64 logical;
	267	u8 *csum;
	268	u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
	269	u8 *csum_allocated;
	270	btrfs_io_bio_end_io_t *end_io;
	271	struct bvec_iter iter;
	272	/*
	273	* This member must come last, bio_alloc_bioset will allocate enough
	274	* bytes for entire btrfs_io_bio but relies on bio being last.
	275	*/
	276	struct bio bio;
	277	};
	278
	279	static inline struct btrfs_io_bio btrfs_io_bio(struct bio bio)
	280	{
	281	return container_of(bio, struct btrfs_io_bio, bio);
	282	}
	283
	284	struct btrfs_bio_stripe {
	285	struct btrfs_device *dev;
	286	u64 physical;
	287	u64 length; /* only used for discard mappings */
	288	};
	289
	290	struct btrfs_bio;
	291	typedef void (btrfs_bio_end_io_t) (struct btrfs_bio *bio, int err);
	292
	293	struct btrfs_bio {
	294	refcount_t refs;
	295	atomic_t stripes_pending;
	296	struct btrfs_fs_info *fs_info;
	297	u64 map_type; /* get from map_lookup->type */
	298	bio_end_io_t *end_io;
	299	struct bio *orig_bio;
	300	unsigned long flags;
	301	void *private;
	302	atomic_t error;
	303	int max_errors;
	304	int num_stripes;
	305	int mirror_num;
	306	int num_tgtdevs;
	307	int *tgtdev_map;
	308	/*
	309	* logical block numbers for the start of each stripe
	310	* The last one or two are p/q. These are sorted,
	311	* so raid_map[0] is the start of our full stripe
	312	*/
	313	u64 *raid_map;
	314	struct btrfs_bio_stripe stripes[];
	315	};
	316
	317	struct btrfs_device_info {
	318	struct btrfs_device *dev;
	319	u64 dev_offset;
	320	u64 max_avail;
	321	u64 total_avail;
	322	};
	323
	324	struct btrfs_raid_attr {
	325	int sub_stripes; /* sub_stripes info for map */
	326	int dev_stripes; /* stripes per dev */
	327	int devs_max; /* max devs to use */
	328	int devs_min; /* min devs needed */
	329	int tolerated_failures; /* max tolerated fail devs */
	330	int devs_increment; /* ndevs has to be a multiple of this */
	331	int ncopies; /* how many copies to data has */
	332	int mindev_error; /* error code if min devs requisite is unmet */
	333	const char raid_name[8]; /* name of the raid */
	334	u64 bg_flag; /* block group flag of the raid */
	335	};
	336
	337	extern const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES];
	338
	339	struct map_lookup {
	340	u64 type;
	341	int io_align;
	342	int io_width;
	343	u64 stripe_len;
	344	int num_stripes;
	345	int sub_stripes;
	346	struct btrfs_bio_stripe stripes[];
	347	};
	348
	349	#define map_lookup_size(n) (sizeof(struct map_lookup) + \
	350	(sizeof(struct btrfs_bio_stripe) * (n)))
	351
	352	struct btrfs_balance_args;
	353	struct btrfs_balance_progress;
	354	struct btrfs_balance_control {
	355	struct btrfs_balance_args data;
	356	struct btrfs_balance_args meta;
	357	struct btrfs_balance_args sys;
	358
	359	u64 flags;
	360
	361	struct btrfs_balance_progress stat;
	362	};
	363
	364	enum btrfs_map_op {
	365	BTRFS_MAP_READ,
	366	BTRFS_MAP_WRITE,
	367	BTRFS_MAP_DISCARD,
	368	BTRFS_MAP_GET_READ_MIRRORS,
	369	};
	370
	371	static inline enum btrfs_map_op btrfs_op(struct bio *bio)
	372	{
	373	switch (bio_op(bio)) {
	374	case REQ_OP_DISCARD:
	375	return BTRFS_MAP_DISCARD;
	376	case REQ_OP_WRITE:
	377	return BTRFS_MAP_WRITE;
	378	default:
	379	WARN_ON_ONCE(1);
	380	case REQ_OP_READ:
	381	return BTRFS_MAP_READ;
	382	}
	383	}
	384
	385	int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
	386	u64 end, u64 *length);
	387	void btrfs_get_bbio(struct btrfs_bio *bbio);
	388	void btrfs_put_bbio(struct btrfs_bio *bbio);
	389	int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
	390	u64 logical, u64 *length,
	391	struct btrfs_bio **bbio_ret, int mirror_num);
	392	int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
	393	u64 logical, u64 *length,
	394	struct btrfs_bio **bbio_ret);
	395	int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
	396	u64 physical, u64 *logical, int naddrs, int *stripe_len);
	397	int btrfs_read_sys_array(struct btrfs_fs_info *fs_info);
	398	int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info);
	399	int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
	400	struct btrfs_fs_info *fs_info, u64 type);
	401	void btrfs_mapping_init(struct btrfs_mapping_tree *tree);
	402	void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree);
	403	blk_status_t btrfs_map_bio(struct btrfs_fs_info fs_info, struct bio bio,
	404	int mirror_num, int async_submit);
	405	int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
	406	fmode_t flags, void *holder);
	407	int btrfs_scan_one_device(const char path, fmode_t flags, void holder,
	408	struct btrfs_fs_devices **fs_devices_ret);
	409	int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
	410	void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step);
	411	void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,
	412	struct btrfs_device device, struct btrfs_device this_dev);
	413	int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
	414	const char *device_path,
	415	struct btrfs_device **device);
	416	int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
	417	const char *devpath,
	418	struct btrfs_device **device);
	419	struct btrfs_device btrfs_alloc_device(struct btrfs_fs_info fs_info,
	420	const u64 *devid,
	421	const u8 *uuid);
	422	void btrfs_free_device(struct btrfs_device *device);
	423	int btrfs_rm_device(struct btrfs_fs_info *fs_info,
	424	const char *device_path, u64 devid);
	425	void __exit btrfs_cleanup_fs_uuids(void);
	426	int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len);
	427	int btrfs_grow_device(struct btrfs_trans_handle *trans,
	428	struct btrfs_device *device, u64 new_size);
	429	struct btrfs_device btrfs_find_device(struct btrfs_fs_info fs_info, u64 devid,
	430	u8 uuid, u8 fsid);
	431	int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
	432	int btrfs_init_new_device(struct btrfs_fs_info fs_info, const char path);
	433	int btrfs_balance(struct btrfs_fs_info *fs_info,
	434	struct btrfs_balance_control *bctl,
	435	struct btrfs_ioctl_balance_args *bargs);
	436	int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info);
	437	int btrfs_recover_balance(struct btrfs_fs_info *fs_info);
	438	int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
	439	int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
	440	int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info);
	441	int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info);
	442	int btrfs_chunk_readonly(struct btrfs_fs_info *fs_info, u64 chunk_offset);
	443	int find_free_dev_extent_start(struct btrfs_transaction *transaction,
	444	struct btrfs_device *device, u64 num_bytes,
	445	u64 search_start, u64 start, u64 max_avail);
	446	int find_free_dev_extent(struct btrfs_trans_handle *trans,
	447	struct btrfs_device *device, u64 num_bytes,
	448	u64 start, u64 max_avail);
	449	void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index);
	450	int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info,
	451	struct btrfs_ioctl_get_dev_stats *stats);
	452	void btrfs_init_devices_late(struct btrfs_fs_info *fs_info);
	453	int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info);
	454	int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
	455	struct btrfs_fs_info *fs_info);
	456	void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
	457	struct btrfs_device *srcdev);
	458	void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
	459	struct btrfs_device *srcdev);
	460	void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
	461	struct btrfs_device *tgtdev);
	462	void btrfs_scratch_superblocks(struct block_device bdev, const char device_path);
	463	int btrfs_is_parity_mirror(struct btrfs_fs_info *fs_info,
	464	u64 logical, u64 len);
	465	unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
	466	u64 logical);
	467	int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
	468	struct btrfs_fs_info *fs_info,
	469	u64 chunk_offset, u64 chunk_size);
	470	int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
	471	struct btrfs_fs_info *fs_info, u64 chunk_offset);
	472
	473	static inline void btrfs_dev_stat_inc(struct btrfs_device *dev,
	474	int index)
	475	{
	476	atomic_inc(dev->dev_stat_values + index);
	477	/*
	478	* This memory barrier orders stores updating statistics before stores
	479	* updating dev_stats_ccnt.
	480	*
	481	* It pairs with smp_rmb() in btrfs_run_dev_stats().
	482	*/
	483	smp_mb__before_atomic();
	484	atomic_inc(&dev->dev_stats_ccnt);
	485	}
	486
	487	static inline int btrfs_dev_stat_read(struct btrfs_device *dev,
	488	int index)
	489	{
	490	return atomic_read(dev->dev_stat_values + index);
	491	}
	492
	493	static inline int btrfs_dev_stat_read_and_reset(struct btrfs_device *dev,
	494	int index)
	495	{
	496	int ret;
	497
	498	ret = atomic_xchg(dev->dev_stat_values + index, 0);
	499	/*
	500	* atomic_xchg implies a full memory barriers as per atomic_t.txt:
	501	* - RMW operations that have a return value are fully ordered;
	502	*
	503	* This implicit memory barriers is paired with the smp_rmb in
	504	* btrfs_run_dev_stats
	505	*/
	506	atomic_inc(&dev->dev_stats_ccnt);
	507	return ret;
	508	}
	509
	510	static inline void btrfs_dev_stat_set(struct btrfs_device *dev,
	511	int index, unsigned long val)
	512	{
	513	atomic_set(dev->dev_stat_values + index, val);
	514	/*
	515	* This memory barrier orders stores updating statistics before stores
	516	* updating dev_stats_ccnt.
	517	*
	518	* It pairs with smp_rmb() in btrfs_run_dev_stats().
	519	*/
	520	smp_mb__before_atomic();
	521	atomic_inc(&dev->dev_stats_ccnt);
	522	}
	523
	524	static inline void btrfs_dev_stat_reset(struct btrfs_device *dev,
	525	int index)
	526	{
	527	btrfs_dev_stat_set(dev, index, 0);
	528	}
	529
	530	/*
	531	* Convert block group flags (BTRFS_BLOCK_GROUP_*) to btrfs_raid_types, which
	532	* can be used as index to access btrfs_raid_array[].
	533	*/
	534	static inline enum btrfs_raid_types btrfs_bg_flags_to_raid_index(u64 flags)
	535	{
	536	if (flags & BTRFS_BLOCK_GROUP_RAID10)
	537	return BTRFS_RAID_RAID10;
	538	else if (flags & BTRFS_BLOCK_GROUP_RAID1)
	539	return BTRFS_RAID_RAID1;
	540	else if (flags & BTRFS_BLOCK_GROUP_DUP)
	541	return BTRFS_RAID_DUP;
	542	else if (flags & BTRFS_BLOCK_GROUP_RAID0)
	543	return BTRFS_RAID_RAID0;
	544	else if (flags & BTRFS_BLOCK_GROUP_RAID5)
	545	return BTRFS_RAID_RAID5;
	546	else if (flags & BTRFS_BLOCK_GROUP_RAID6)
	547	return BTRFS_RAID_RAID6;
	548
	549	return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
	550	}
	551
	552	const char *get_raid_name(enum btrfs_raid_types type);
	553
	554	void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info);
	555	void btrfs_update_commit_device_bytes_used(struct btrfs_transaction *trans);
	556
	557	struct list_head *btrfs_get_fs_uuids(void);
	558	void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info);
	559	void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info);
	560	bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
	561	struct btrfs_device *failing_dev);
	562
	563	#endif