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Diffstat (limited to 'fs/btrfs/transaction.h')
| -rw-r--r-- | fs/btrfs/transaction.h | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h new file mode 100644 index 000000000..3a57f227b --- /dev/null +++ b/fs/btrfs/transaction.h @@ -0,0 +1,348 @@ +/* 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/build_bug.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; +struct extent_buffer; + +/* + * 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) + +/* + * Number of extent buffers a transaction handle tracks for writeback + * inhibition. The CLOCK reference bits pack into a u32 so this must not exceed + * 32, and keeping it a power of two lets the compiler reduce the CLOCK hand + * modulo to a mask. + */ +#define BTRFS_INHIBITED_EBS_SLOTS 8 + +static_assert(BTRFS_INHIBITED_EBS_SLOTS <= 32); +static_assert(BTRFS_INHIBITED_EBS_SLOTS != 0 && + (BTRFS_INHIBITED_EBS_SLOTS & (BTRFS_INHIBITED_EBS_SLOTS - 1)) == 0); + +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; + + /* Extent buffers this handle has inhibited writeback on. */ + struct extent_buffer *inhibited_ebs[BTRFS_INHIBITED_EBS_SLOTS]; + /* CLOCK reference bit per slot. */ + u32 inhibited_ebs_referenced; + u32 nr_inhibited_ebs; + /* CLOCK hand. */ + u32 inhibited_ebs_hand; +}; + +/* + * 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; +} + +/* + * Compile-time and run-time verification of error passed to transaction abort. + * Direct constants will be caught at compile time, errors read from variables + * can be caught only at run-time and will warn under debugging config. + * + * How verification works: + * - accepted builtin constants are all -EIO and such + * - for compile-time check, invalid condition produces a negative-sized array + * type, valid zero-sized + * - when a variable is passed as error the first check is a no-op + * - with enabled debugging, the second array type size is constructed from the + * real variable value, valid condition produces array of size 1 + * - sizeof(type) does not generate any code + */ +#define VERIFY_NEGATIVE_ERROR(error) \ +do { \ + (void)sizeof(char[-!(__builtin_constant_p(error) ? (error) < 0 : 1)]); \ + if (IS_ENABLED(CONFIG_BTRFS_DEBUG)) { \ + if (sizeof(char[(error) < 0]) != 1) \ + DEBUG_WARN("error >= 0 passed to btrfs_abort_transaction()"); \ + } \ +} while(0) + +/* + * 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. + * + * Error number must be negative as it encodes wheather it's the first abort. + */ +#define btrfs_abort_transaction(trans, error) \ +do { \ + int __error = (error); \ + \ + VERIFY_NEGATIVE_ERROR(error); \ + /* Report first abort since mount */ \ + if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED, \ + &((trans)->fs_info->fs_state))) { \ + WARN_ON(btrfs_abort_should_print_stack(__error)); \ + __error = -__error; \ + } \ + __btrfs_abort_transaction((trans), __func__, \ + __LINE__, __error); \ +} 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); + +int __init btrfs_transaction_init(void); +void __cold btrfs_transaction_exit(void); + +#endif |