text: /* 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"
  
  #define BTRFS_MAX_DATA_CHUNK_SIZE	(10ULL * SZ_1G)
  
  extern struct mutex uuid_mutex;
  
  #define BTRFS_STRIPE_LEN	SZ_64K
  
  struct btrfs_io_geometry {
  	/* remaining bytes before crossing a stripe */
  	u64 len;
  	/* offset of logical address in chunk */
  	u64 offset;
  	/* length of single IO stripe */
  	u64 stripe_len;
  	/* number of stripe where address falls */
  	u64 stripe_nr;
  	/* offset of address in stripe */
  	u64 stripe_offset;
  	/* offset of raid56 stripe into the chunk */
  	u64 raid56_stripe_offset;
  };
  
  /*
   * 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)
  
  struct btrfs_zoned_device_info;
  
  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;
  
  	struct rcu_string __rcu *name;
  
  	u64 generation;
  
  	struct block_device *bdev;
  
  	struct btrfs_zoned_device_info *zone_info;
  
  	/* the mode sent to blkdev_get */
  	fmode_t mode;
  
  	unsigned long dev_state;
  	blk_status_t last_flush_error;
  
  #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 chunk mutex
  	 */
  	u64 commit_total_bytes;
  
  	/* bytes used on the current transaction */
  	u64 commit_bytes_used;
  
  	/* for sending down flush barriers */
  	struct bio *flush_bio;
  	struct completion flush_wait;
  
  	/* per-device scrub information */
  	struct scrub_ctx *scrub_ctx;
  
  	/* 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];
  
  	struct extent_io_tree alloc_state;
  
  	struct completion kobj_unregister;
  	/* For sysfs/FSID/devinfo/devid/ */
  	struct kobject devid_kobj;
  };
  
  /*
   * 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,
  };
  
  /*
   * 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,
  	BTRFS_NR_READ_POLICY,
  };
  
  struct btrfs_fs_devices {
  	u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
  	u8 metadata_uuid[BTRFS_FSID_SIZE];
  	bool fsid_change;
  	struct list_head fs_list;
  
  	u64 num_devices;
  	u64 open_devices;
  	u64 rw_devices;
  	u64 missing_devices;
  	u64 total_rw_bytes;
  	u64 total_devices;
  
  	/* Highest generation number of seen devices */
  	u64 latest_generation;
  
  	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;
  
  	/* 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;
  	bool seeding;
  
  	int opened;
  
  	/* set when we find or add a device that doesn't have the
  	 * nonrot flag set
  	 */
  	bool rotating;
  
  	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;
  };
  
  #define BTRFS_BIO_INLINE_CSUM_SIZE	64
  
  #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)
  
  /*
   * 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.
   */
  struct btrfs_io_bio {
  	unsigned int mirror_num;
  	struct btrfs_device *device;
  	u64 logical;
  	u8 *csum;
  	u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
  	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);
  }
  
  static inline void btrfs_io_bio_free_csum(struct btrfs_io_bio *io_bio)
  {
  	if (io_bio->csum != io_bio->csum_inline) {
  		kfree(io_bio->csum);
  		io_bio->csum = NULL;
  	}
  }
  
  struct btrfs_bio_stripe {
  	struct btrfs_device *dev;
  	u64 physical;
  	u64 length; /* only used for discard mappings */
  };
  
  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;
  	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 {
  	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 map_lookup {
  	u64 type;
  	int io_align;
  	int io_width;
  	u64 stripe_len;
  	int num_stripes;
  	int sub_stripes;
  	int verified_stripes; /* For mount time dev extent verification */
  	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:
  	case REQ_OP_ZONE_APPEND:
  		return BTRFS_MAP_WRITE;
  	default:
  		WARN_ON_ONCE(1);
  		fallthrough;
  	case REQ_OP_READ:
  		return BTRFS_MAP_READ;
  	}
  }
  
  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_get_io_geometry(struct btrfs_fs_info *fs_info, struct extent_map *map,
  			  enum btrfs_map_op op, u64 logical, u64 len,
  			  struct btrfs_io_geometry *io_geom);
  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_alloc_chunk(struct btrfs_trans_handle *trans,
  					    u64 type);
  void btrfs_mapping_tree_free(struct extent_map_tree *tree);
  blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
  			   int mirror_num);
  int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
  		       fmode_t flags, void *holder);
  struct btrfs_device *btrfs_scan_one_device(const char *path,
  					   fmode_t flags, void *holder);
  int btrfs_forget_devices(const char *path);
  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);
  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_devices *fs_devices,
  				       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);
  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_cancel_balance(struct btrfs_fs_info *fs_info);
  int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info);
  int btrfs_uuid_scan_kthread(void *data);
  int btrfs_chunk_readonly(struct btrfs_fs_info *fs_info, u64 chunk_offset);
  int find_free_dev_extent(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);
  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);
  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,
  			     u64 chunk_offset, u64 chunk_size);
  int btrfs_chunk_alloc_add_chunk_item(struct btrfs_trans_handle *trans,
  				     struct btrfs_block_group *bg);
  int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset);
  struct extent_map *btrfs_get_chunk_map(struct btrfs_fs_info *fs_info,
  				       u64 logical, u64 length);
  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);
  }
  
  /*
   * 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_RAID1C3)
  		return BTRFS_RAID_RAID1C3;
  	else if (flags & BTRFS_BLOCK_GROUP_RAID1C4)
  		return BTRFS_RAID_RAID1C4;
  	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 */
  }
  
  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 block_device *bdev,
  			       const char *device_path);
  
  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);
  int btrfs_repair_one_zone(struct btrfs_fs_info *fs_info, u64 logical);
  
  #endif
  