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

#ifndef BTRFS_CTREE_H
#define BTRFS_CTREE_H

#include <linux/cleanup.h>
#include <linux/spinlock.h>
#include <linux/rbtree.h>
#include <linux/mutex.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/atomic.h>
#include <linux/xarray.h>
#include <linux/refcount.h>
#include <uapi/linux/btrfs_tree.h>
#include "locking.h"
#include "accessors.h"

struct extent_buffer;
struct btrfs_block_rsv;
struct btrfs_trans_handle;
struct btrfs_block_group;

/* Read ahead values for struct btrfs_path.reada */
enum {
        READA_NONE,
        READA_BACK,
        READA_FORWARD,
        /*
         * Similar to READA_FORWARD but unlike it:
         *
         * 1) It will trigger readahead even for leaves that are not close to
         *    each other on disk;
         * 2) It also triggers readahead for nodes;
         * 3) During a search, even when a node or leaf is already in memory, it
         *    will still trigger readahead for other nodes and leaves that follow
         *    it.
         *
         * This is meant to be used only when we know we are iterating over the
         * entire tree or a very large part of it.
         */
        READA_FORWARD_ALWAYS,
};

/*
 * btrfs_paths remember the path taken from the root down to the leaf.
 * level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
 * to any other levels that are present.
 *
 * The slots array records the index of the item or block pointer
 * used while walking the tree.
 */
struct btrfs_path {
        struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
        int slots[BTRFS_MAX_LEVEL];
        /* if there is real range locking, this locks field will change */
        u8 locks[BTRFS_MAX_LEVEL];
        u8 reada;
        u8 lowest_level;

        /*
         * set by btrfs_split_item, tells search_slot to keep all locks
         * and to force calls to keep space in the nodes
         */
        bool search_for_split:1;
        /* Keep some upper locks as we walk down. */
        bool keep_locks:1;
        bool skip_locking:1;
        bool search_commit_root:1;
        bool need_commit_sem:1;
        bool skip_release_on_error:1;
        /*
         * Indicate that new item (btrfs_search_slot) is extending already
         * existing item and ins_len contains only the data size and not item
         * header (ie. sizeof(struct btrfs_item) is not included).
         */
        bool search_for_extension:1;
        /* Stop search if any locks need to be taken (for read) */
        bool nowait:1;
};

#define BTRFS_PATH_AUTO_FREE(path_name)                                 \
        struct btrfs_path *path_name __free(btrfs_free_path) = NULL

/*
 * This defines an on-stack path that will be auto released when exiting the scope.
 *
 * It is compatible with any existing manual btrfs_release_path() calls.
 */
#define BTRFS_PATH_AUTO_RELEASE(path_name)                                      \
        struct btrfs_path path_name __free(btrfs_release_path) = { 0 }

/*
 * The state of btrfs root
 */
enum {
        /*
         * btrfs_record_root_in_trans is a multi-step process, and it can race
         * with the balancing code.   But the race is very small, and only the
         * first time the root is added to each transaction.  So IN_TRANS_SETUP
         * is used to tell us when more checks are required
         */
        BTRFS_ROOT_IN_TRANS_SETUP,

        /*
         * Set if tree blocks of this root can be shared by other roots.
         * Only subvolume trees and their reloc trees have this bit set.
         * Conflicts with TRACK_DIRTY bit.
         *
         * This affects two things:
         *
         * - How balance works
         *   For shareable roots, we need to use reloc tree and do path
         *   replacement for balance, and need various pre/post hooks for
         *   snapshot creation to handle them.
         *
         *   While for non-shareable trees, we just simply do a tree search
         *   with COW.
         *
         * - How dirty roots are tracked
         *   For shareable roots, btrfs_record_root_in_trans() is needed to
         *   track them, while non-subvolume roots have TRACK_DIRTY bit, they
         *   don't need to set this manually.
         */
        BTRFS_ROOT_SHAREABLE,
        BTRFS_ROOT_TRACK_DIRTY,
        BTRFS_ROOT_IN_RADIX,
        BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
        BTRFS_ROOT_DEFRAG_RUNNING,
        BTRFS_ROOT_FORCE_COW,
        BTRFS_ROOT_MULTI_LOG_TASKS,
        BTRFS_ROOT_DIRTY,
        BTRFS_ROOT_DELETING,

        /*
         * Reloc tree is orphan, only kept here for qgroup delayed subtree scan
         *
         * Set for the subvolume tree owning the reloc tree.
         */
        BTRFS_ROOT_DEAD_RELOC_TREE,
        /* Mark dead root stored on device whose cleanup needs to be resumed */
        BTRFS_ROOT_DEAD_TREE,
        /* The root has a log tree. Used for subvolume roots and the tree root. */
        BTRFS_ROOT_HAS_LOG_TREE,
        /* Qgroup flushing is in progress */
        BTRFS_ROOT_QGROUP_FLUSHING,
        /* We started the orphan cleanup for this root. */
        BTRFS_ROOT_ORPHAN_CLEANUP,
        /* This root has a drop operation that was started previously. */
        BTRFS_ROOT_UNFINISHED_DROP,
        /* This reloc root needs to have its buffers lockdep class reset. */
        BTRFS_ROOT_RESET_LOCKDEP_CLASS,
};

/*
 * Record swapped tree blocks of a subvolume tree for delayed subtree trace
 * code. For detail check comment in fs/btrfs/qgroup.c.
 */
struct btrfs_qgroup_swapped_blocks {
        spinlock_t lock;
        /* RM_EMPTY_ROOT() of above blocks[] */
        bool swapped;
        struct rb_root blocks[BTRFS_MAX_LEVEL];
};

/*
 * in ram representation of the tree.  extent_root is used for all allocations
 * and for the extent tree extent_root root.
 */
struct btrfs_root {
        struct rb_node rb_node;

        struct extent_buffer *node;

        struct extent_buffer *commit_root;
        struct btrfs_root *log_root;
        struct btrfs_root *reloc_root;

        unsigned long state;
        struct btrfs_root_item root_item;
        struct btrfs_key root_key;
        struct btrfs_fs_info *fs_info;
        struct extent_io_tree dirty_log_pages;

        struct mutex objectid_mutex;

        spinlock_t accounting_lock;
        struct btrfs_block_rsv *block_rsv;

        struct mutex log_mutex;
        wait_queue_head_t log_writer_wait;
        wait_queue_head_t log_commit_wait[2];
        struct list_head log_ctxs[2];
        /* Used only for log trees of subvolumes, not for the log root tree */
        atomic_t log_writers;
        atomic_t log_commit[2];
        /* Used only for log trees of subvolumes, not for the log root tree */
        atomic_t log_batch;
        /*
         * Protected by the 'log_mutex' lock but can be read without holding
         * that lock to avoid unnecessary lock contention, in which case it
         * should be read using btrfs_get_root_log_transid() except if it's a
         * log tree in which case it can be directly accessed. Updates to this
         * field should always use btrfs_set_root_log_transid(), except for log
         * trees where the field can be updated directly.
         */
        int log_transid;
        /* No matter the commit succeeds or not*/
        int log_transid_committed;
        /*
         * Just be updated when the commit succeeds. Use
         * btrfs_get_root_last_log_commit() and btrfs_set_root_last_log_commit()
         * to access this field.
         */
        int last_log_commit;
        pid_t log_start_pid;

        u64 last_trans;

        u64 free_objectid;

        struct btrfs_key defrag_progress;
        struct btrfs_key defrag_max;

        /* The dirty list is only used by non-shareable roots */
        struct list_head dirty_list;

        struct list_head root_list;

        /* Xarray that keeps track of in-memory inodes. */
        struct xarray inodes;

        /* Xarray that keeps track of delayed nodes of every inode. */
        struct xarray delayed_nodes;
        /*
         * right now this just gets used so that a root has its own devid
         * for stat.  It may be used for more later
         */
        dev_t anon_dev;

        spinlock_t root_item_lock;
        refcount_t refs;

        struct mutex delalloc_mutex;
        spinlock_t delalloc_lock;
        /*
         * all of the inodes that have delalloc bytes.  It is possible for
         * this list to be empty even when there is still dirty data=ordered
         * extents waiting to finish IO.
         */
        struct list_head delalloc_inodes;
        struct list_head delalloc_root;
        u64 nr_delalloc_inodes;

        struct mutex ordered_extent_mutex;
        /*
         * this is used by the balancing code to wait for all the pending
         * ordered extents
         */
        spinlock_t ordered_extent_lock;

        /*
         * all of the data=ordered extents pending writeback
         * these can span multiple transactions and basically include
         * every dirty data page that isn't from nodatacow
         */
        struct list_head ordered_extents;
        struct list_head ordered_root;
        u64 nr_ordered_extents;

        /*
         * Not empty if this subvolume root has gone through tree block swap
         * (relocation)
         *
         * Will be used by reloc_control::dirty_subvol_roots.
         */
        struct list_head reloc_dirty_list;

        /*
         * Number of currently running SEND ioctls to prevent
         * manipulation with the read-only status via SUBVOL_SETFLAGS
         */
        int send_in_progress;
        /*
         * Number of currently running deduplication operations that have a
         * destination inode belonging to this root. Protected by the lock
         * root_item_lock.
         */
        int dedupe_in_progress;
        /* For exclusion of snapshot creation and nocow writes */
        struct btrfs_drew_lock snapshot_lock;

        atomic_t snapshot_force_cow;

        /* For qgroup metadata reserved space */
        spinlock_t qgroup_meta_rsv_lock;
        u64 qgroup_meta_rsv_pertrans;
        u64 qgroup_meta_rsv_prealloc;
        wait_queue_head_t qgroup_flush_wait;

        /* Number of active swapfiles */
        atomic_t nr_swapfiles;

        /* Record pairs of swapped blocks for qgroup */
        struct btrfs_qgroup_swapped_blocks swapped_blocks;

        /* Used only by log trees, when logging csum items */
        struct extent_io_tree log_csum_range;

        /* Used in simple quotas, track root during relocation. */
        u64 relocation_src_root;

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
        u64 alloc_bytenr;
#endif

#ifdef CONFIG_BTRFS_DEBUG
        struct list_head leak_list;
#endif
};

static inline bool btrfs_root_readonly(const struct btrfs_root *root)
{
        /* Byte-swap the constant at compile time, root_item::flags is LE */
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
}

static inline bool btrfs_root_dead(const struct btrfs_root *root)
{
        /* Byte-swap the constant at compile time, root_item::flags is LE */
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
}

static inline u64 btrfs_root_id(const struct btrfs_root *root)
{
        return root->root_key.objectid;
}

static inline int btrfs_get_root_log_transid(const struct btrfs_root *root)
{
        return READ_ONCE(root->log_transid);
}

static inline void btrfs_set_root_log_transid(struct btrfs_root *root, int log_transid)
{
        WRITE_ONCE(root->log_transid, log_transid);
}

static inline int btrfs_get_root_last_log_commit(const struct btrfs_root *root)
{
        return READ_ONCE(root->last_log_commit);
}

static inline void btrfs_set_root_last_log_commit(struct btrfs_root *root, int commit_id)
{
        WRITE_ONCE(root->last_log_commit, commit_id);
}

static inline u64 btrfs_get_root_last_trans(const struct btrfs_root *root)
{
        return READ_ONCE(root->last_trans);
}

static inline void btrfs_set_root_last_trans(struct btrfs_root *root, u64 transid)
{
        WRITE_ONCE(root->last_trans, transid);
}

/*
 * Return the generation this root started with.
 *
 * Every normal root that is created with root->root_key.offset set to it's
 * originating generation.  If it is a snapshot it is the generation when the
 * snapshot was created.
 *
 * However for TREE_RELOC roots root_key.offset is the objectid of the owning
 * tree root.  Thankfully we copy the root item of the owning tree root, which
 * has it's last_snapshot set to what we would have root_key.offset set to, so
 * return that if this is a TREE_RELOC root.
 */
static inline u64 btrfs_root_origin_generation(const struct btrfs_root *root)
{
        if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID)
                return btrfs_root_last_snapshot(&root->root_item);
        return root->root_key.offset;
}

/*
 * Structure that conveys information about an extent that is going to replace
 * all the extents in a file range.
 */
struct btrfs_replace_extent_info {
        u64 disk_offset;
        u64 disk_len;
        u64 data_offset;
        u64 data_len;
        u64 file_offset;
        /* Pointer to a file extent item of type regular or prealloc. */
        char *extent_buf;
        /*
         * Set to true when attempting to replace a file range with a new extent
         * described by this structure, set to false when attempting to clone an
         * existing extent into a file range.
         */
        bool is_new_extent;
        /* Indicate if we should update the inode's mtime and ctime. */
        bool update_times;
        /* Meaningful only if is_new_extent is true. */
        int qgroup_reserved;
        /*
         * Meaningful only if is_new_extent is true.
         * Used to track how many extent items we have already inserted in a
         * subvolume tree that refer to the extent described by this structure,
         * so that we know when to create a new delayed ref or update an existing
         * one.
         */
        int insertions;
};

/* Arguments for btrfs_drop_extents() */
struct btrfs_drop_extents_args {
        /* Input parameters */

        /*
         * If NULL, btrfs_drop_extents() will allocate and free its own path.
         * If 'replace_extent' is true, this must not be NULL. Also the path
         * is always released except if 'replace_extent' is true and
         * btrfs_drop_extents() sets 'extent_inserted' to true, in which case
         * the path is kept locked.
         */
        struct btrfs_path *path;
        /* Start offset of the range to drop extents from */
        u64 start;
        /* End (exclusive, last byte + 1) of the range to drop extents from */
        u64 end;
        /* If true drop all the extent maps in the range */
        bool drop_cache;
        /*
         * If true it means we want to insert a new extent after dropping all
         * the extents in the range. If this is true, the 'extent_item_size'
         * parameter must be set as well and the 'extent_inserted' field will
         * be set to true by btrfs_drop_extents() if it could insert the new
         * extent.
         * Note: when this is set to true the path must not be NULL.
         */
        bool replace_extent;
        /*
         * Used if 'replace_extent' is true. Size of the file extent item to
         * insert after dropping all existing extents in the range
         */
        u32 extent_item_size;

        /* Output parameters */

        /*
         * Set to the minimum between the input parameter 'end' and the end
         * (exclusive, last byte + 1) of the last dropped extent. This is always
         * set even if btrfs_drop_extents() returns an error.
         */
        u64 drop_end;
        /*
         * The number of allocated bytes found in the range. This can be smaller
         * than the range's length when there are holes in the range.
         */
        u64 bytes_found;
        /*
         * Only set if 'replace_extent' is true. Set to true if we were able
         * to insert a replacement extent after dropping all extents in the
         * range, otherwise set to false by btrfs_drop_extents().
         * Also, if btrfs_drop_extents() has set this to true it means it
         * returned with the path locked, otherwise if it has set this to
         * false it has returned with the path released.
         */
        bool extent_inserted;
};

struct btrfs_file_private {
        void *filldir_buf;
        u64 last_index;
        struct extent_state *llseek_cached_state;
        /* Task that allocated this structure. */
        struct task_struct *owner_task;
};

static inline u32 BTRFS_LEAF_DATA_SIZE(const struct btrfs_fs_info *info)
{
        return info->nodesize - sizeof(struct btrfs_header);
}

static inline u32 BTRFS_MAX_ITEM_SIZE(const struct btrfs_fs_info *info)
{
        return BTRFS_LEAF_DATA_SIZE(info) - sizeof(struct btrfs_item);
}

static inline u32 BTRFS_NODEPTRS_PER_BLOCK(const struct btrfs_fs_info *info)
{
        return BTRFS_LEAF_DATA_SIZE(info) / sizeof(struct btrfs_key_ptr);
}

static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
{
        return BTRFS_MAX_ITEM_SIZE(info) - sizeof(struct btrfs_dir_item);
}

int __init btrfs_ctree_init(void);
void __cold btrfs_ctree_exit(void);

int btrfs_bin_search(const struct extent_buffer *eb, int first_slot,
                     const struct btrfs_key *key, int *slot);

int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);

#ifdef __LITTLE_ENDIAN

/*
 * Compare two keys, on little-endian the disk order is same as CPU order and
 * we can avoid the conversion.
 */
static inline int btrfs_comp_keys(const struct btrfs_disk_key *disk_key,
                                  const struct btrfs_key *k2)
{
        const struct btrfs_key *k1 = (const struct btrfs_key *)disk_key;

        return btrfs_comp_cpu_keys(k1, k2);
}

#else

/* Compare two keys in a memcmp fashion. */
static inline int btrfs_comp_keys(const struct btrfs_disk_key *disk,
                                  const struct btrfs_key *k2)
{
        struct btrfs_key k1;

        btrfs_disk_key_to_cpu(&k1, disk);

        return btrfs_comp_cpu_keys(&k1, k2);
}

#endif

int btrfs_previous_item(struct btrfs_root *root,
                        struct btrfs_path *path, u64 min_objectid,
                        int type);
int btrfs_previous_extent_item(struct btrfs_root *root,
                        struct btrfs_path *path, u64 min_objectid);
void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
                             const struct btrfs_path *path,
                             const struct btrfs_key *new_key);
struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
                        struct btrfs_key *key, int lowest_level,
                        u64 min_trans);
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
                         struct btrfs_path *path,
                         u64 min_trans);
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
                                           int slot);

int btrfs_cow_block(struct btrfs_trans_handle *trans,
                    struct btrfs_root *root, struct extent_buffer *buf,
                    struct extent_buffer *parent, int parent_slot,
                    struct extent_buffer **cow_ret,
                    enum btrfs_lock_nesting nest);
int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root,
                          struct extent_buffer *buf,
                          struct extent_buffer *parent, int parent_slot,
                          struct extent_buffer **cow_ret,
                          u64 search_start, u64 empty_size,
                          enum btrfs_lock_nesting nest);
int btrfs_copy_root(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root,
                      struct extent_buffer *buf,
                      struct extent_buffer **cow_ret, u64 new_root_objectid);
bool btrfs_block_can_be_shared(const struct btrfs_trans_handle *trans,
                               const struct btrfs_root *root,
                               const struct extent_buffer *buf);
int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                  struct btrfs_path *path, int level, int slot);
void btrfs_extend_item(struct btrfs_trans_handle *trans,
                       const struct btrfs_path *path, u32 data_size);
void btrfs_truncate_item(struct btrfs_trans_handle *trans,
                         const struct btrfs_path *path, u32 new_size, int from_end);
int btrfs_split_item(struct btrfs_trans_handle *trans,
                     struct btrfs_root *root,
                     struct btrfs_path *path,
                     const struct btrfs_key *new_key,
                     unsigned long split_offset);
int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root,
                         struct btrfs_path *path,
                         const struct btrfs_key *new_key);
int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
                u64 inum, u64 ioff, u8 key_type, struct btrfs_key *found_key);
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                      const struct btrfs_key *key, struct btrfs_path *p,
                      int ins_len, int cow);
int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
                          struct btrfs_path *p, u64 time_seq);
int btrfs_search_slot_for_read(struct btrfs_root *root,
                               const struct btrfs_key *key,
                               struct btrfs_path *p, int find_higher,
                               int return_any);
void btrfs_release_path(struct btrfs_path *p);
struct btrfs_path *btrfs_alloc_path(void);
void btrfs_free_path(struct btrfs_path *p);
DEFINE_FREE(btrfs_free_path, struct btrfs_path *, btrfs_free_path(_T))
DEFINE_FREE(btrfs_release_path, struct btrfs_path, btrfs_release_path(&_T))

int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   struct btrfs_path *path, int slot, int nr);
static inline int btrfs_del_item(struct btrfs_trans_handle *trans,
                                 struct btrfs_root *root,
                                 struct btrfs_path *path)
{
        return btrfs_del_items(trans, root, path, path->slots[0], 1);
}

/*
 * Describes a batch of items to insert in a btree. This is used by
 * btrfs_insert_empty_items().
 */
struct btrfs_item_batch {
        /*
         * Pointer to an array containing the keys of the items to insert (in
         * sorted order).
         */
        const struct btrfs_key *keys;
        /* Pointer to an array containing the data size for each item to insert. */
        const u32 *data_sizes;
        /*
         * The sum of data sizes for all items. The caller can compute this while
         * setting up the data_sizes array, so it ends up being more efficient
         * than having btrfs_insert_empty_items() or setup_item_for_insert()
         * doing it, as it would avoid an extra loop over a potentially large
         * array, and in the case of setup_item_for_insert(), we would be doing
         * it while holding a write lock on a leaf and often on upper level nodes
         * too, unnecessarily increasing the size of a critical section.
         */
        u32 total_data_size;
        /* Size of the keys and data_sizes arrays (number of items in the batch). */
        int nr;
};

void btrfs_setup_item_for_insert(struct btrfs_trans_handle *trans,
                                 struct btrfs_root *root,
                                 struct btrfs_path *path,
                                 const struct btrfs_key *key,
                                 u32 data_size);
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                      const struct btrfs_key *key, void *data, u32 data_size);
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root,
                             struct btrfs_path *path,
                             const struct btrfs_item_batch *batch);

static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
                                          struct btrfs_root *root,
                                          struct btrfs_path *path,
                                          const struct btrfs_key *key,
                                          u32 data_size)
{
        struct btrfs_item_batch batch;

        batch.keys = key;
        batch.data_sizes = &data_size;
        batch.total_data_size = data_size;
        batch.nr = 1;

        return btrfs_insert_empty_items(trans, root, path, &batch);
}

int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
                        u64 time_seq);

int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key,
                           struct btrfs_path *path);

int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key,
                              struct btrfs_path *path);

/*
 * Search in @root for a given @key, and store the slot found in @found_key.
 *
 * @root:       The root node of the tree.
 * @key:        The key we are looking for.
 * @found_key:  Will hold the found item.
 * @path:       Holds the current slot/leaf.
 * @iter_ret:   Contains the value returned from btrfs_search_slot or
 *              btrfs_get_next_valid_item, whichever was executed last.
 *
 * The @iter_ret is an output variable that will contain the return value of
 * btrfs_search_slot, if it encountered an error, or the value returned from
 * btrfs_get_next_valid_item otherwise. That return value can be 0, if a valid
 * slot was found, 1 if there were no more leaves, and <0 if there was an error.
 *
 * It's recommended to use a separate variable for iter_ret and then use it to
 * set the function return value so there's no confusion of the 0/1/errno
 * values stemming from btrfs_search_slot.
 */
#define btrfs_for_each_slot(root, key, found_key, path, iter_ret)               \
        for (iter_ret = btrfs_search_slot(NULL, (root), (key), (path), 0, 0);   \
                (iter_ret) >= 0 &&                                              \
                (iter_ret = btrfs_get_next_valid_item((root), (found_key), (path))) == 0; \
                (path)->slots[0]++                                              \
        )

int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *path, u64 time_seq);

/*
 * Search the tree again to find a leaf with greater keys.
 *
 * Returns 0 if it found something or 1 if there are no greater leaves.
 * Returns < 0 on error.
 */
static inline int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
        return btrfs_next_old_leaf(root, path, 0);
}

static inline int btrfs_next_item(struct btrfs_root *root, struct btrfs_path *p)
{
        return btrfs_next_old_item(root, p, 0);
}
int btrfs_leaf_free_space(const struct extent_buffer *leaf);

static inline bool btrfs_is_fstree(u64 rootid)
{
        if (rootid == BTRFS_FS_TREE_OBJECTID)
                return true;

        if ((s64)rootid < (s64)BTRFS_FIRST_FREE_OBJECTID)
                return false;

        if (btrfs_qgroup_level(rootid) != 0)
                return false;

        return true;
}

static inline bool btrfs_is_data_reloc_root(const struct btrfs_root *root)
{
        return root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID;
}

#endif