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

#ifndef BTRFS_TRANSACTION_H
#define BTRFS_TRANSACTION_H

#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/list.h>
#include <linux/time64.h>
#include <linux/mutex.h>
#include <linux/wait.h>
#include "btrfs_inode.h"
#include "delayed-ref.h"

struct dentry;
struct inode;
struct btrfs_pending_snapshot;
struct btrfs_fs_info;
struct btrfs_root_item;
struct btrfs_root;
struct btrfs_path;

/*
 * Signal that a direct IO write is in progress, to avoid deadlock for sync
 * direct IO writes when fsync is called during the direct IO write path.
 */
#define BTRFS_TRANS_DIO_WRITE_STUB      ((void *) 1)

/* Radix-tree tag for roots that are part of the transaction. */
#define BTRFS_ROOT_TRANS_TAG                    0

enum btrfs_trans_state {
        TRANS_STATE_RUNNING,
        TRANS_STATE_COMMIT_PREP,
        TRANS_STATE_COMMIT_START,
        TRANS_STATE_COMMIT_DOING,
        TRANS_STATE_UNBLOCKED,
        TRANS_STATE_SUPER_COMMITTED,
        TRANS_STATE_COMPLETED,
        TRANS_STATE_MAX,
};

#define BTRFS_TRANS_HAVE_FREE_BGS       0
#define BTRFS_TRANS_DIRTY_BG_RUN        1
#define BTRFS_TRANS_CACHE_ENOSPC        2

struct btrfs_transaction {
        u64 transid;
        /*
         * total external writers(USERSPACE/START/ATTACH) in this
         * transaction, it must be zero before the transaction is
         * being committed
         */
        atomic_t num_extwriters;
        /*
         * total writers in this transaction, it must be zero before the
         * transaction can end
         */
        atomic_t num_writers;
        refcount_t use_count;

        unsigned long flags;

        /* Be protected by fs_info->trans_lock when we want to change it. */
        enum btrfs_trans_state state;
        int aborted;
        struct list_head list;
        struct extent_io_tree dirty_pages;
        time64_t start_time;
        wait_queue_head_t writer_wait;
        wait_queue_head_t commit_wait;
        struct list_head pending_snapshots;
        struct list_head dev_update_list;
        struct list_head switch_commits;
        struct list_head dirty_bgs;

        /*
         * There is no explicit lock which protects io_bgs, rather its
         * consistency is implied by the fact that all the sites which modify
         * it do so under some form of transaction critical section, namely:
         *
         * - btrfs_start_dirty_block_groups - This function can only ever be
         *   run by one of the transaction committers. Refer to
         *   BTRFS_TRANS_DIRTY_BG_RUN usage in btrfs_commit_transaction
         *
         * - btrfs_write_dirty_blockgroups - this is called by
         *   commit_cowonly_roots from transaction critical section
         *   (TRANS_STATE_COMMIT_DOING)
         *
         * - btrfs_cleanup_dirty_bgs - called on transaction abort
         */
        struct list_head io_bgs;
        struct list_head dropped_roots;
        struct extent_io_tree pinned_extents;

        /*
         * we need to make sure block group deletion doesn't race with
         * free space cache writeout.  This mutex keeps them from stomping
         * on each other
         */
        struct mutex cache_write_mutex;
        spinlock_t dirty_bgs_lock;
        /* Protected by spin lock fs_info->unused_bgs_lock. */
        struct list_head deleted_bgs;
        spinlock_t dropped_roots_lock;
        struct btrfs_delayed_ref_root delayed_refs;
        struct btrfs_fs_info *fs_info;

        /*
         * Number of ordered extents the transaction must wait for before
         * committing. These are ordered extents started by a fast fsync.
         */
        atomic_t pending_ordered;
        wait_queue_head_t pending_wait;
};

enum {
        ENUM_BIT(__TRANS_FREEZABLE),
        ENUM_BIT(__TRANS_START),
        ENUM_BIT(__TRANS_ATTACH),
        ENUM_BIT(__TRANS_JOIN),
        ENUM_BIT(__TRANS_JOIN_NOLOCK),
        ENUM_BIT(__TRANS_DUMMY),
        ENUM_BIT(__TRANS_JOIN_NOSTART),
};

#define TRANS_START             (__TRANS_START | __TRANS_FREEZABLE)
#define TRANS_ATTACH            (__TRANS_ATTACH)
#define TRANS_JOIN              (__TRANS_JOIN | __TRANS_FREEZABLE)
#define TRANS_JOIN_NOLOCK       (__TRANS_JOIN_NOLOCK)
#define TRANS_JOIN_NOSTART      (__TRANS_JOIN_NOSTART)

#define TRANS_EXTWRITERS        (__TRANS_START | __TRANS_ATTACH)

struct btrfs_trans_handle {
        u64 transid;
        u64 bytes_reserved;
        u64 delayed_refs_bytes_reserved;
        u64 chunk_bytes_reserved;
        unsigned long delayed_ref_updates;
        unsigned long delayed_ref_csum_deletions;
        struct btrfs_transaction *transaction;
        struct btrfs_block_rsv *block_rsv;
        struct btrfs_block_rsv *orig_rsv;
        /* Set by a task that wants to create a snapshot. */
        struct btrfs_pending_snapshot *pending_snapshot;
        refcount_t use_count;
        unsigned int type;
        /*
         * Error code of transaction abort, set outside of locks and must use
         * the READ_ONCE/WRITE_ONCE access
         */
        short aborted;
        bool adding_csums;
        bool allocating_chunk;
        bool removing_chunk;
        bool reloc_reserved;
        bool in_fsync;
        struct btrfs_fs_info *fs_info;
        struct list_head new_bgs;
        struct btrfs_block_rsv delayed_rsv;
};

/*
 * The abort status can be changed between calls and is not protected by locks.
 * This accepts btrfs_transaction and btrfs_trans_handle as types. Once it's
 * set to a non-zero value it does not change, so the macro should be in checks
 * but is not necessary for further reads of the value.
 */
#define TRANS_ABORTED(trans)            (unlikely(READ_ONCE((trans)->aborted)))

struct btrfs_pending_snapshot {
        struct dentry *dentry;
        struct btrfs_inode *dir;
        struct btrfs_root *root;
        struct btrfs_root_item *root_item;
        struct btrfs_root *snap;
        struct btrfs_qgroup_inherit *inherit;
        struct btrfs_path *path;
        /* block reservation for the operation */
        struct btrfs_block_rsv block_rsv;
        /* extra metadata reservation for relocation */
        int error;
        /* Preallocated anonymous block device number */
        dev_t anon_dev;
        bool readonly;
        struct list_head list;
};

static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
                                              struct btrfs_inode *inode)
{
        spin_lock(&inode->lock);
        inode->last_trans = trans->transaction->transid;
        inode->last_sub_trans = btrfs_get_root_log_transid(inode->root);
        inode->last_log_commit = inode->last_sub_trans - 1;
        spin_unlock(&inode->lock);
}

/*
 * Make qgroup codes to skip given qgroupid, means the old/new_roots for
 * qgroup won't contain the qgroupid in it.
 */
static inline void btrfs_set_skip_qgroup(struct btrfs_trans_handle *trans,
                                         u64 qgroupid)
{
        struct btrfs_delayed_ref_root *delayed_refs;

        delayed_refs = &trans->transaction->delayed_refs;
        WARN_ON(delayed_refs->qgroup_to_skip);
        delayed_refs->qgroup_to_skip = qgroupid;
}

static inline void btrfs_clear_skip_qgroup(struct btrfs_trans_handle *trans)
{
        struct btrfs_delayed_ref_root *delayed_refs;

        delayed_refs = &trans->transaction->delayed_refs;
        WARN_ON(!delayed_refs->qgroup_to_skip);
        delayed_refs->qgroup_to_skip = 0;
}

/*
 * We want the transaction abort to print stack trace only for errors where the
 * cause could be a bug, eg. due to ENOSPC, and not for common errors that are
 * caused by external factors.
 */
static inline bool btrfs_abort_should_print_stack(int error)
{
        switch (error) {
        case -EIO:
        case -EROFS:
        case -ENOMEM:
                return false;
        }
        return true;
}

/*
 * Call btrfs_abort_transaction as early as possible when an error condition is
 * detected, that way the exact stack trace is reported for some errors.
 */
#define btrfs_abort_transaction(trans, error)           \
do {                                                            \
        bool __first = false;                                   \
        /* Report first abort since mount */                    \
        if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,     \
                        &((trans)->fs_info->fs_state))) {       \
                __first = true;                                 \
                if (WARN(btrfs_abort_should_print_stack(error), \
                        KERN_ERR                                \
                        "BTRFS: Transaction aborted (error %d)\n",      \
                        (error))) {                                     \
                        /* Stack trace printed. */                      \
                } else {                                                \
                        btrfs_err((trans)->fs_info,                     \
                                  "Transaction aborted (error %d)",     \
                                  (error));                     \
                }                                               \
        }                                                       \
        __btrfs_abort_transaction((trans), __func__,            \
                                  __LINE__, (error), __first);  \
} while (0)

int btrfs_end_transaction(struct btrfs_trans_handle *trans);
struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
                                                   unsigned int num_items);
struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
                                        struct btrfs_root *root,
                                        unsigned int num_items);
struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_attach_transaction_barrier(
                                        struct btrfs_root *root);
int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid);

void btrfs_add_dead_root(struct btrfs_root *root);
void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info);
int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info);
int btrfs_commit_transaction(struct btrfs_trans_handle *trans);
void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans);
int btrfs_commit_current_transaction(struct btrfs_root *root);
int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans);
bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans);
void btrfs_throttle(struct btrfs_fs_info *fs_info);
int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
                                struct btrfs_root *root);
int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
                                struct extent_io_tree *dirty_pages, int mark);
int btrfs_wait_tree_log_extents(struct btrfs_root *root, int mark);
int btrfs_transaction_blocked(struct btrfs_fs_info *info);
void btrfs_put_transaction(struct btrfs_transaction *transaction);
void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root);
void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans);
void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
                                      const char *function,
                                      unsigned int line, int error, bool first_hit);

int __init btrfs_transaction_init(void);
void __cold btrfs_transaction_exit(void);

#endif