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

#ifndef BTRFS_VOLUMES_H
#define BTRFS_VOLUMES_H

#include <linux/blk_types.h>
#include <linux/blkdev.h>
#include <linux/sizes.h>
#include <linux/atomic.h>
#include <linux/sort.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/log2.h>
#include <linux/kobject.h>
#include <linux/refcount.h>
#include <linux/completion.h>
#include <linux/rbtree.h>
#include <uapi/linux/btrfs.h>
#include <uapi/linux/btrfs_tree.h>
#include "messages.h"
#include "extent-io-tree.h"

struct block_device;
struct bdev_handle;
struct btrfs_fs_info;
struct btrfs_block_group;
struct btrfs_trans_handle;
struct btrfs_transaction;
struct btrfs_zoned_device_info;
struct btrfs_space_info;

#define BTRFS_MAX_DATA_CHUNK_SIZE       (10ULL * SZ_1G)

/*
 * Arbitrary maximum size of one discard request to limit potentially long time
 * spent in blkdev_issue_discard().
 */
#define BTRFS_MAX_DISCARD_CHUNK_SIZE    (SZ_1G)

extern struct mutex uuid_mutex;

#define BTRFS_STRIPE_LEN                SZ_64K
#define BTRFS_STRIPE_LEN_SHIFT          (16)
#define BTRFS_STRIPE_LEN_MASK           (BTRFS_STRIPE_LEN - 1)

static_assert(ilog2(BTRFS_STRIPE_LEN) == BTRFS_STRIPE_LEN_SHIFT);

/* Used by sanity check for btrfs_raid_types. */
#define const_ffs(n) (__builtin_ctzll(n) + 1)

/*
 * The conversion from BTRFS_BLOCK_GROUP_* bits to btrfs_raid_type requires
 * RAID0 always to be the lowest profile bit.
 * Although it's part of on-disk format and should never change, do extra
 * compile-time sanity checks.
 */
static_assert(const_ffs(BTRFS_BLOCK_GROUP_RAID0) <
              const_ffs(BTRFS_BLOCK_GROUP_PROFILE_MASK & ~BTRFS_BLOCK_GROUP_RAID0));

/* ilog2() can handle both constants and variables */
#define BTRFS_BG_FLAG_TO_INDEX(profile)                                 \
        ilog2((profile) >> (ilog2(BTRFS_BLOCK_GROUP_RAID0) - 1))

enum btrfs_raid_types {
        /* SINGLE is the special one as it doesn't have on-disk bit. */
        BTRFS_RAID_SINGLE  = 0,

        BTRFS_RAID_RAID0   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID0),
        BTRFS_RAID_RAID1   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID1),
        BTRFS_RAID_DUP     = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_DUP),
        BTRFS_RAID_RAID10  = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID10),
        BTRFS_RAID_RAID5   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID5),
        BTRFS_RAID_RAID6   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID6),
        BTRFS_RAID_RAID1C3 = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID1C3),
        BTRFS_RAID_RAID1C4 = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID1C4),

        BTRFS_NR_RAID_TYPES
};

static_assert(BTRFS_RAID_RAID0 == 1);
static_assert(BTRFS_RAID_RAID1 == 2);
static_assert(BTRFS_RAID_DUP == 3);
static_assert(BTRFS_RAID_RAID10 == 4);
static_assert(BTRFS_RAID_RAID5 == 5);
static_assert(BTRFS_RAID_RAID6 == 6);
static_assert(BTRFS_RAID_RAID1C3 == 7);
static_assert(BTRFS_RAID_RAID1C4 == 8);

/*
 * 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)
#define BTRFS_DEV_STATE_NO_READA        (5)
#define BTRFS_DEV_STATE_FLUSH_FAILED    (6)

/* Set when the device item is found in chunk tree, used to catch unexpected registered device. */
#define BTRFS_DEV_STATE_ITEM_FOUND      (7)

/* Special value encoding failure to write primary super block. */
#define BTRFS_SUPER_PRIMARY_WRITE_ERROR         (INT_MAX / 2)

struct btrfs_fs_devices;

struct btrfs_device {
        struct list_head dev_list; /* device_list_mutex */
        struct list_head dev_alloc_list; /* chunk mutex */
        struct list_head post_commit_list; /* chunk mutex */
        struct btrfs_fs_devices *fs_devices;
        struct btrfs_fs_info *fs_info;

        /* Device path or NULL if missing. */
        const char __rcu *name;

        u64 generation;

        struct file *bdev_file;
        struct block_device *bdev;

        struct btrfs_zoned_device_info *zone_info;

        unsigned long dev_state;

#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;

        /*
         * Counter of super block write errors, values larger than
         * BTRFS_SUPER_PRIMARY_WRITE_ERROR encode primary super block write failure.
         */
        atomic_t sb_write_errors;

        /* 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 chunk mutex
         */
        u64 commit_total_bytes;

        /* bytes used on the current transaction */
        u64 commit_bytes_used;

        /* Bio used for flushing device barriers */
        struct bio flush_bio;
        struct completion flush_wait;

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

        /* 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];

        /*
         * Device's major-minor number. Must be set even if the device is not
         * opened (bdev == NULL), unless the device is missing.
         */
        dev_t devt;

        struct extent_io_tree alloc_state;

        struct completion kobj_unregister;
        /* For sysfs/FSID/devinfo/devid/ */
        struct kobject devid_kobj;

        /* Bandwidth limit for scrub, in bytes */
        u64 scrub_speed_max;
};

/*
 * Block group or device which contains an active swapfile. Used for preventing
 * unsafe operations while a swapfile is active.
 *
 * These are sorted on (ptr, inode) (note that a block group or device can
 * contain more than one swapfile). We compare the pointer values because we
 * don't actually care what the object is, we just need a quick check whether
 * the object exists in the rbtree.
 */
struct btrfs_swapfile_pin {
        struct rb_node node;
        void *ptr;
        struct inode *inode;
        /*
         * If true, ptr points to a struct btrfs_block_group. Otherwise, ptr
         * points to a struct btrfs_device.
         */
        bool is_block_group;
        /*
         * Only used when 'is_block_group' is true and it is the number of
         * extents used by a swapfile for this block group ('ptr' field).
         */
        int bg_extent_count;
};

/*
 * 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_PREEMPTION)
#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);

enum btrfs_chunk_allocation_policy {
        BTRFS_CHUNK_ALLOC_REGULAR,
        BTRFS_CHUNK_ALLOC_ZONED,
};

#define BTRFS_DEFAULT_RR_MIN_CONTIG_READ        (SZ_256K)
/* Keep in sync with raid_attr table, current maximum is RAID1C4. */
#define BTRFS_RAID1_MAX_MIRRORS                 (4)
/*
 * Read policies for mirrored block group profiles, read picks the stripe based
 * on these policies.
 */
enum btrfs_read_policy {
        /* Use process PID to choose the stripe */
        BTRFS_READ_POLICY_PID,
#ifdef CONFIG_BTRFS_EXPERIMENTAL
        /* Balancing RAID1 reads across all striped devices (round-robin). */
        BTRFS_READ_POLICY_RR,
        /* Read from a specific device. */
        BTRFS_READ_POLICY_DEVID,
#endif
        BTRFS_NR_READ_POLICY,
};

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

        /*
         * UUID written into the btree blocks:
         *
         * - If metadata_uuid != fsid then super block must have
         *   BTRFS_FEATURE_INCOMPAT_METADATA_UUID flag set.
         *
         * - Following shall be true at all times:
         *   - metadata_uuid == btrfs_header::fsid
         *   - metadata_uuid == btrfs_dev_item::fsid
         *
         * - Relations between fsid and metadata_uuid in sb and fs_devices:
         *   - Normal:
         *       fs_devices->fsid == fs_devices->metadata_uuid == sb->fsid
         *       sb->metadata_uuid == 0
         *
         *   - When the BTRFS_FEATURE_INCOMPAT_METADATA_UUID flag is set:
         *       fs_devices->fsid == sb->fsid
         *       fs_devices->metadata_uuid == sb->metadata_uuid
         *
         *   - When in-memory fs_devices->temp_fsid is true
         *       fs_devices->fsid = random
         *       fs_devices->metadata_uuid == sb->fsid
         */
        u8 metadata_uuid[BTRFS_FSID_SIZE];

        struct list_head fs_list;

        /*
         * Number of devices under this fsid including missing and
         * replace-target device and excludes seed devices.
         */
        u64 num_devices;

        /*
         * The number of devices that successfully opened, including
         * replace-target, excludes seed devices.
         */
        u64 open_devices;

        /* The number of devices that are under the chunk allocation list. */
        u64 rw_devices;

        /* Count of missing devices under this fsid excluding seed device. */
        u64 missing_devices;
        u64 total_rw_bytes;

        /*
         * Count of devices from btrfs_super_block::num_devices for this fsid,
         * which includes the seed device, excludes the transient replace-target
         * device.
         */
        u64 total_devices;

        /* Highest generation number of seen devices */
        u64 latest_generation;

        /*
         * The mount device or a device with highest generation after removal
         * or replace.
         */
        struct btrfs_device *latest_dev;

        /*
         * All of the devices in the filesystem, protected by a mutex so we can
         * safely walk it to write out the super blocks without worrying about
         * adding/removing by the multi-device code. Scrubbing super block can
         * kick off supers writing by holding this mutex lock.
         */
        struct mutex device_list_mutex;

        /* List of all devices, protected by device_list_mutex */
        struct list_head devices;

        /* Devices which can satisfy space allocation. Protected by * chunk_mutex. */
        struct list_head alloc_list;

        struct list_head seed_list;

        /* Count fs-devices opened. */
        int opened;

        /*
         * Counter of the processes that are holding this fs_devices but not
         * yet opened.
         * This is for mounting handling, as we can only open the fs_devices
         * after a super block is created.  But we cannot take uuid_mutex
         * during sget_fc(), thus we have to hold the fs_devices (meaning it
         * cannot be released) until a super block is returned.
         */
        int holding;

        /* Set when we find or add a device that doesn't have the nonrot flag set. */
        bool rotating;
        /* Devices support TRIM/discard commands. */
        bool discardable;
        /* The filesystem is a seed filesystem. */
        bool seeding;
        /* The mount needs to use a randomly generated fsid. */
        bool temp_fsid;
        /* Enable/disable the filesystem stats tracking. */
        bool collect_fs_stats;

        struct btrfs_fs_info *fs_info;
        /* sysfs kobjects */
        struct kobject fsid_kobj;
        struct kobject *devices_kobj;
        struct kobject *devinfo_kobj;
        struct completion kobj_unregister;

        enum btrfs_chunk_allocation_policy chunk_alloc_policy;

        /* Policy used to read the mirrored stripes. */
        enum btrfs_read_policy read_policy;

#ifdef CONFIG_BTRFS_EXPERIMENTAL
        /*
         * Minimum contiguous reads before switching to next device, the unit
         * is one block/sectorsize.
         */
        u32 rr_min_contig_read;

        /* Device to be used for reading in case of RAID1. */
        u64 read_devid;
#endif
};

#define BTRFS_MAX_DEVS(info) ((BTRFS_MAX_ITEM_SIZE(info)        \
                        - sizeof(struct btrfs_chunk))           \
                        / sizeof(struct btrfs_stripe) + 1)

#define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE        \
                                - 2 * sizeof(struct btrfs_disk_key)     \
                                - 2 * sizeof(struct btrfs_chunk))       \
                                / sizeof(struct btrfs_stripe) + 1)

struct btrfs_io_stripe {
        struct btrfs_device *dev;
        /* Block mapping. */
        u64 physical;
        bool rst_search_commit_root;
        /* For the endio handler. */
        struct btrfs_io_context *bioc;
};

struct btrfs_discard_stripe {
        struct btrfs_device *dev;
        u64 physical;
        u64 length;
};

/*
 * Context for IO submission for device stripe.
 *
 * - Track the unfinished mirrors for mirror based profiles
 *   Mirror based profiles are SINGLE/DUP/RAID1/RAID10.
 *
 * - Contain the logical -> physical mapping info
 *   Used by submit_stripe_bio() for mapping logical bio
 *   into physical device address.
 *
 * - Contain device replace info
 *   Used by handle_ops_on_dev_replace() to copy logical bios
 *   into the new device.
 *
 * - Contain RAID56 full stripe logical bytenrs
 */
struct btrfs_io_context {
        refcount_t refs;
        struct btrfs_fs_info *fs_info;
        /* Taken from struct btrfs_chunk_map::type. */
        u64 map_type;
        struct bio *orig_bio;
        atomic_t error;
        u16 max_errors;
        bool use_rst;

        u64 logical;
        u64 size;
        /* Raid stripe tree ordered entry. */
        struct list_head rst_ordered_entry;

        /*
         * The total number of stripes, including the extra duplicated
         * stripe for replace.
         */
        u16 num_stripes;

        /*
         * The mirror_num of this bioc.
         *
         * This is for reads which use 0 as mirror_num, thus we should return a
         * valid mirror_num (>0) for the reader.
         */
        u16 mirror_num;

        /*
         * The following two members are for dev-replace case only.
         *
         * @replace_nr_stripes: Number of duplicated stripes which need to be
         *                      written to replace target.
         *                      Should be <= 2 (2 for DUP, otherwise <= 1).
         * @replace_stripe_src: The array indicates where the duplicated stripes
         *                      are from.
         *
         * The @replace_stripe_src[] array is mostly for RAID56 cases.
         * As non-RAID56 stripes share the same contents of the mapped range,
         * thus no need to bother where the duplicated ones are from.
         *
         * But for RAID56 case, all stripes contain different contents, thus
         * we need a way to know the mapping.
         *
         * There is an example for the two members, using a RAID5 write:
         *
         *   num_stripes:       4 (3 + 1 duplicated write)
         *   stripes[0]:        dev = devid 1, physical = X
         *   stripes[1]:        dev = devid 2, physical = Y
         *   stripes[2]:        dev = devid 3, physical = Z
         *   stripes[3]:        dev = devid 0, physical = Y
         *
         * replace_nr_stripes = 1
         * replace_stripe_src = 1       <- Means stripes[1] is involved in replace.
         *                                 The duplicated stripe index would be
         *                                 (@num_stripes - 1).
         *
         * Note, that we can still have cases replace_nr_stripes = 2 for DUP.
         * In that case, all stripes share the same content, thus we don't
         * need to bother @replace_stripe_src value at all.
         */
        u16 replace_nr_stripes;
        s16 replace_stripe_src;
        /*
         * Logical bytenr of the full stripe start, only for RAID56 cases.
         *
         * When this value is set to other than (u64)-1, the stripes[] should
         * follow this pattern:
         *
         * (real_stripes = num_stripes - replace_nr_stripes)
         * (data_stripes = (is_raid6) ? (real_stripes - 2) : (real_stripes - 1))
         *
         * stripes[0]:                  The first data stripe
         * stripes[1]:                  The second data stripe
         * ...
         * stripes[data_stripes - 1]:   The last data stripe
         * stripes[data_stripes]:       The P stripe
         * stripes[data_stripes + 1]:   The Q stripe (only for RAID6).
         */
        u64 full_stripe_logical;
        struct btrfs_io_stripe stripes[];
};

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

struct btrfs_raid_attr {
        u8 sub_stripes;         /* sub_stripes info for map */
        u8 dev_stripes;         /* stripes per dev */
        u8 devs_max;            /* max devs to use */
        u8 devs_min;            /* min devs needed */
        u8 tolerated_failures;  /* max tolerated fail devs */
        u8 devs_increment;      /* ndevs has to be a multiple of this */
        u8 ncopies;             /* how many copies to data has */
        u8 nparity;             /* number of stripes worth of bytes to store
                                 * parity information */
        u8 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 btrfs_chunk_map {
        struct rb_node rb_node;
        /* For mount time dev extent verification. */
        int verified_stripes;
        refcount_t refs;
        u64 start;
        u64 chunk_len;
        u64 stripe_size;
        u64 type;
        int io_align;
        int io_width;
        int num_stripes;
        int sub_stripes;
        struct btrfs_io_stripe stripes[];
};

#define btrfs_chunk_map_size(n) (sizeof(struct btrfs_chunk_map) + \
                                 (sizeof(struct btrfs_io_stripe) * (n)))

static inline void btrfs_free_chunk_map(struct btrfs_chunk_map *map)
{
        if (map && refcount_dec_and_test(&map->refs)) {
                ASSERT(RB_EMPTY_NODE(&map->rb_node));
                kfree(map);
        }
}
DEFINE_FREE(btrfs_free_chunk_map, struct btrfs_chunk_map *, btrfs_free_chunk_map(_T))

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;
};

/*
 * Search for a given device by the set parameters
 */
struct btrfs_dev_lookup_args {
        u64 devid;
        u8 *uuid;
        u8 *fsid;
        /*
         * If devt is specified, all other members will be ignored as it is
         * enough to uniquely locate a device.
         */
        dev_t devt;
        bool missing;
};

/* We have to initialize to -1 because BTRFS_DEV_REPLACE_DEVID is 0 */
#define BTRFS_DEV_LOOKUP_ARGS_INIT { .devid = (u64)-1 }

#define BTRFS_DEV_LOOKUP_ARGS(name) \
        struct btrfs_dev_lookup_args name = BTRFS_DEV_LOOKUP_ARGS_INIT

enum btrfs_map_op {
        BTRFS_MAP_READ,
        BTRFS_MAP_WRITE,
        BTRFS_MAP_GET_READ_MIRRORS,
};

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

static inline unsigned long btrfs_chunk_item_size(int num_stripes)
{
        ASSERT(num_stripes);
        return sizeof(struct btrfs_chunk) +
                sizeof(struct btrfs_stripe) * (num_stripes - 1);
}

/*
 * Do the type safe conversion from stripe_nr to offset inside the chunk.
 *
 * @stripe_nr is u32, with left shift it can overflow u32 for chunks larger
 * than 4G.  This does the proper type cast to avoid overflow.
 */
static inline u64 btrfs_stripe_nr_to_offset(u32 stripe_nr)
{
        return (u64)stripe_nr << BTRFS_STRIPE_LEN_SHIFT;
}

void btrfs_get_bioc(struct btrfs_io_context *bioc);
void btrfs_put_bioc(struct btrfs_io_context *bioc);
int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
                    u64 logical, u64 *length,
                    struct btrfs_io_context **bioc_ret,
                    struct btrfs_io_stripe *smap, int *mirror_num_ret);
int btrfs_map_repair_block(struct btrfs_fs_info *fs_info,
                           struct btrfs_io_stripe *smap, u64 logical,
                           u32 length, int mirror_num);
struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
                                               u64 logical, u64 *length_ret,
                                               u32 *num_stripes, bool do_remap);
int btrfs_read_sys_array(struct btrfs_fs_info *fs_info);
int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info);
struct btrfs_block_group *btrfs_create_chunk(struct btrfs_trans_handle *trans,
                                             struct btrfs_space_info *space_info,
                                             u64 type);
void btrfs_mapping_tree_free(struct btrfs_fs_info *fs_info);
int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                       blk_mode_t flags, void *holder);
struct btrfs_device *btrfs_scan_one_device(const char *path, bool mount_arg_dev);
int btrfs_forget_devices(dev_t devt);
void btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices);
void btrfs_assign_next_active_device(struct btrfs_device *device,
                                     struct btrfs_device *this_dev);
struct btrfs_device *btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info,
                                                  u64 devid,
                                                  const char *devpath);
int btrfs_get_dev_args_from_path(struct btrfs_fs_info *fs_info,
                                 struct btrfs_dev_lookup_args *args,
                                 const char *path);
struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
                                        const u64 *devid, const u8 *uuid,
                                        const char *path);
void btrfs_put_dev_args_from_path(struct btrfs_dev_lookup_args *args);
int btrfs_rm_device(struct btrfs_fs_info *fs_info,
                    struct btrfs_dev_lookup_args *args,
                    struct file **bdev_file);
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(const struct btrfs_fs_devices *fs_devices,
                                       const struct btrfs_dev_lookup_args *args);
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);
void btrfs_describe_block_groups(u64 flags, char *buf, u32 size_buf);
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_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset,
                         bool verbose);
int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
bool btrfs_chunk_writeable(struct btrfs_fs_info *fs_info, u64 chunk_offset);
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);
int 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);
void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_device *srcdev);
void btrfs_rm_dev_replace_free_srcdev(struct btrfs_device *srcdev);
void btrfs_destroy_dev_replace_tgtdev(struct btrfs_device *tgtdev);
unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
                                    u64 logical);
u64 btrfs_calc_stripe_length(const struct btrfs_chunk_map *map);
int btrfs_nr_parity_stripes(u64 type);
int btrfs_chunk_alloc_add_chunk_item(struct btrfs_trans_handle *trans,
                                     struct btrfs_block_group *bg);
int btrfs_remove_dev_extents(struct btrfs_trans_handle *trans, struct btrfs_chunk_map *map);
int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset);

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
struct btrfs_chunk_map *btrfs_alloc_chunk_map(int num_stripes, gfp_t gfp);
int btrfs_add_chunk_map(struct btrfs_fs_info *fs_info, struct btrfs_chunk_map *map);
#endif

struct btrfs_chunk_map *btrfs_find_chunk_map(struct btrfs_fs_info *fs_info,
                                             u64 logical, u64 length);
struct btrfs_chunk_map *btrfs_find_chunk_map_nolock(struct btrfs_fs_info *fs_info,
                                                    u64 logical, u64 length);
struct btrfs_chunk_map *btrfs_get_chunk_map(struct btrfs_fs_info *fs_info,
                                            u64 logical, u64 length);
void btrfs_remove_chunk_map(struct btrfs_fs_info *fs_info, struct btrfs_chunk_map *map);
struct btrfs_super_block *btrfs_read_disk_super(struct block_device *bdev,
                                                int copy_num, bool drop_cache);
void btrfs_release_disk_super(struct btrfs_super_block *super);

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 const char *btrfs_dev_name(const struct btrfs_device *device)
{
        if (!device || test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
                return "<missing disk>";
        else
                return rcu_dereference(device->name);
}

static inline void btrfs_warn_unknown_chunk_allocation(enum btrfs_chunk_allocation_policy pol)
{
        WARN_ONCE(1, "unknown allocation policy %d, fallback to regular", pol);
}

static inline void btrfs_fs_devices_inc_holding(struct btrfs_fs_devices *fs_devices)
{
        lockdep_assert_held(&uuid_mutex);
        ASSERT(fs_devices->holding >= 0);
        fs_devices->holding++;
}

static inline void btrfs_fs_devices_dec_holding(struct btrfs_fs_devices *fs_devices)
{
        lockdep_assert_held(&uuid_mutex);
        ASSERT(fs_devices->holding > 0);
        fs_devices->holding--;
}

void btrfs_commit_device_sizes(struct btrfs_transaction *trans);

struct list_head * __attribute_const__ btrfs_get_fs_uuids(void);
bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
                                        struct btrfs_device *failing_dev);
void btrfs_scratch_superblocks(struct btrfs_fs_info *fs_info, struct btrfs_device *device);

enum btrfs_raid_types __attribute_const__ btrfs_bg_flags_to_raid_index(u64 flags);
int btrfs_bg_type_to_factor(u64 flags);
const char *btrfs_bg_type_to_raid_name(u64 flags);
int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info);
bool btrfs_verify_dev_items(const struct btrfs_fs_info *fs_info);
bool btrfs_repair_one_zone(struct btrfs_fs_info *fs_info, u64 logical);

bool btrfs_pinned_by_swapfile(struct btrfs_fs_info *fs_info, void *ptr);
const u8 *btrfs_sb_fsid_ptr(const struct btrfs_super_block *sb);
int btrfs_update_device(struct btrfs_trans_handle *trans, struct btrfs_device *device);
void btrfs_chunk_map_device_clear_bits(struct btrfs_chunk_map *map, unsigned int bits);

bool btrfs_first_pending_extent(struct btrfs_device *device, u64 start, u64 len,
                                u64 *pending_start, u64 *pending_end);
bool btrfs_find_hole_in_pending_extents(struct btrfs_device *device,
                                        u64 *start, u64 *len, u64 min_hole_size);

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
struct btrfs_io_context *alloc_btrfs_io_context(struct btrfs_fs_info *fs_info,
                                                u64 logical, u16 total_stripes);
#endif

#endif