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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#ifndef BTRFS_TRANSACTION_H
7#define BTRFS_TRANSACTION_H
8
9#include <linux/atomic.h>
10#include <linux/refcount.h>
11#include <linux/list.h>
12#include <linux/time64.h>
13#include <linux/mutex.h>
14#include <linux/wait.h>
15#include "btrfs_inode.h"
16#include "delayed-ref.h"
17
18struct dentry;
19struct inode;
20struct btrfs_pending_snapshot;
21struct btrfs_fs_info;
22struct btrfs_root_item;
23struct btrfs_root;
24struct btrfs_path;
25
26/*
27 * Signal that a direct IO write is in progress, to avoid deadlock for sync
28 * direct IO writes when fsync is called during the direct IO write path.
29 */
30#define BTRFS_TRANS_DIO_WRITE_STUB ((void *) 1)
31
32/* Radix-tree tag for roots that are part of the transaction. */
33#define BTRFS_ROOT_TRANS_TAG 0
34
35enum btrfs_trans_state {
36 TRANS_STATE_RUNNING,
37 TRANS_STATE_COMMIT_PREP,
38 TRANS_STATE_COMMIT_START,
39 TRANS_STATE_COMMIT_DOING,
40 TRANS_STATE_UNBLOCKED,
41 TRANS_STATE_SUPER_COMMITTED,
42 TRANS_STATE_COMPLETED,
43 TRANS_STATE_MAX,
44};
45
46#define BTRFS_TRANS_HAVE_FREE_BGS 0
47#define BTRFS_TRANS_DIRTY_BG_RUN 1
48#define BTRFS_TRANS_CACHE_ENOSPC 2
49
50struct btrfs_transaction {
51 u64 transid;
52 /*
53 * total external writers(USERSPACE/START/ATTACH) in this
54 * transaction, it must be zero before the transaction is
55 * being committed
56 */
57 atomic_t num_extwriters;
58 /*
59 * total writers in this transaction, it must be zero before the
60 * transaction can end
61 */
62 atomic_t num_writers;
63 refcount_t use_count;
64
65 unsigned long flags;
66
67 /* Be protected by fs_info->trans_lock when we want to change it. */
68 enum btrfs_trans_state state;
69 int aborted;
70 struct list_head list;
71 struct extent_io_tree dirty_pages;
72 time64_t start_time;
73 wait_queue_head_t writer_wait;
74 wait_queue_head_t commit_wait;
75 struct list_head pending_snapshots;
76 struct list_head dev_update_list;
77 struct list_head switch_commits;
78 struct list_head dirty_bgs;
79
80 /*
81 * There is no explicit lock which protects io_bgs, rather its
82 * consistency is implied by the fact that all the sites which modify
83 * it do so under some form of transaction critical section, namely:
84 *
85 * - btrfs_start_dirty_block_groups - This function can only ever be
86 * run by one of the transaction committers. Refer to
87 * BTRFS_TRANS_DIRTY_BG_RUN usage in btrfs_commit_transaction
88 *
89 * - btrfs_write_dirty_blockgroups - this is called by
90 * commit_cowonly_roots from transaction critical section
91 * (TRANS_STATE_COMMIT_DOING)
92 *
93 * - btrfs_cleanup_dirty_bgs - called on transaction abort
94 */
95 struct list_head io_bgs;
96 struct list_head dropped_roots;
97 struct extent_io_tree pinned_extents;
98
99 /*
100 * we need to make sure block group deletion doesn't race with
101 * free space cache writeout. This mutex keeps them from stomping
102 * on each other
103 */
104 struct mutex cache_write_mutex;
105 spinlock_t dirty_bgs_lock;
106 /* Protected by spin lock fs_info->unused_bgs_lock. */
107 struct list_head deleted_bgs;
108 spinlock_t dropped_roots_lock;
109 struct btrfs_delayed_ref_root delayed_refs;
110 struct btrfs_fs_info *fs_info;
111
112 /*
113 * Number of ordered extents the transaction must wait for before
114 * committing. These are ordered extents started by a fast fsync.
115 */
116 atomic_t pending_ordered;
117 wait_queue_head_t pending_wait;
118};
119
120enum {
121 ENUM_BIT(__TRANS_FREEZABLE),
122 ENUM_BIT(__TRANS_START),
123 ENUM_BIT(__TRANS_ATTACH),
124 ENUM_BIT(__TRANS_JOIN),
125 ENUM_BIT(__TRANS_JOIN_NOLOCK),
126 ENUM_BIT(__TRANS_DUMMY),
127 ENUM_BIT(__TRANS_JOIN_NOSTART),
128};
129
130#define TRANS_START (__TRANS_START | __TRANS_FREEZABLE)
131#define TRANS_ATTACH (__TRANS_ATTACH)
132#define TRANS_JOIN (__TRANS_JOIN | __TRANS_FREEZABLE)
133#define TRANS_JOIN_NOLOCK (__TRANS_JOIN_NOLOCK)
134#define TRANS_JOIN_NOSTART (__TRANS_JOIN_NOSTART)
135
136#define TRANS_EXTWRITERS (__TRANS_START | __TRANS_ATTACH)
137
138struct btrfs_trans_handle {
139 u64 transid;
140 u64 bytes_reserved;
141 u64 delayed_refs_bytes_reserved;
142 u64 chunk_bytes_reserved;
143 unsigned long delayed_ref_updates;
144 unsigned long delayed_ref_csum_deletions;
145 struct btrfs_transaction *transaction;
146 struct btrfs_block_rsv *block_rsv;
147 struct btrfs_block_rsv *orig_rsv;
148 /* Set by a task that wants to create a snapshot. */
149 struct btrfs_pending_snapshot *pending_snapshot;
150 refcount_t use_count;
151 unsigned int type;
152 /*
153 * Error code of transaction abort, set outside of locks and must use
154 * the READ_ONCE/WRITE_ONCE access
155 */
156 short aborted;
157 bool adding_csums;
158 bool allocating_chunk;
159 bool removing_chunk;
160 bool reloc_reserved;
161 bool in_fsync;
162 struct btrfs_fs_info *fs_info;
163 struct list_head new_bgs;
164 struct btrfs_block_rsv delayed_rsv;
165};
166
167/*
168 * The abort status can be changed between calls and is not protected by locks.
169 * This accepts btrfs_transaction and btrfs_trans_handle as types. Once it's
170 * set to a non-zero value it does not change, so the macro should be in checks
171 * but is not necessary for further reads of the value.
172 */
173#define TRANS_ABORTED(trans) (unlikely(READ_ONCE((trans)->aborted)))
174
175struct btrfs_pending_snapshot {
176 struct dentry *dentry;
177 struct btrfs_inode *dir;
178 struct btrfs_root *root;
179 struct btrfs_root_item *root_item;
180 struct btrfs_root *snap;
181 struct btrfs_qgroup_inherit *inherit;
182 struct btrfs_path *path;
183 /* block reservation for the operation */
184 struct btrfs_block_rsv block_rsv;
185 /* extra metadata reservation for relocation */
186 int error;
187 /* Preallocated anonymous block device number */
188 dev_t anon_dev;
189 bool readonly;
190 struct list_head list;
191};
192
193static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
194 struct btrfs_inode *inode)
195{
196 spin_lock(&inode->lock);
197 inode->last_trans = trans->transaction->transid;
198 inode->last_sub_trans = btrfs_get_root_log_transid(inode->root);
199 inode->last_log_commit = inode->last_sub_trans - 1;
200 spin_unlock(&inode->lock);
201}
202
203/*
204 * Make qgroup codes to skip given qgroupid, means the old/new_roots for
205 * qgroup won't contain the qgroupid in it.
206 */
207static inline void btrfs_set_skip_qgroup(struct btrfs_trans_handle *trans,
208 u64 qgroupid)
209{
210 struct btrfs_delayed_ref_root *delayed_refs;
211
212 delayed_refs = &trans->transaction->delayed_refs;
213 WARN_ON(delayed_refs->qgroup_to_skip);
214 delayed_refs->qgroup_to_skip = qgroupid;
215}
216
217static inline void btrfs_clear_skip_qgroup(struct btrfs_trans_handle *trans)
218{
219 struct btrfs_delayed_ref_root *delayed_refs;
220
221 delayed_refs = &trans->transaction->delayed_refs;
222 WARN_ON(!delayed_refs->qgroup_to_skip);
223 delayed_refs->qgroup_to_skip = 0;
224}
225
226/*
227 * We want the transaction abort to print stack trace only for errors where the
228 * cause could be a bug, eg. due to ENOSPC, and not for common errors that are
229 * caused by external factors.
230 */
231static inline bool btrfs_abort_should_print_stack(int error)
232{
233 switch (error) {
234 case -EIO:
235 case -EROFS:
236 case -ENOMEM:
237 return false;
238 }
239 return true;
240}
241
242/*
243 * Call btrfs_abort_transaction as early as possible when an error condition is
244 * detected, that way the exact stack trace is reported for some errors.
245 */
246#define btrfs_abort_transaction(trans, error) \
247do { \
248 bool __first = false; \
249 /* Report first abort since mount */ \
250 if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED, \
251 &((trans)->fs_info->fs_state))) { \
252 __first = true; \
253 if (WARN(btrfs_abort_should_print_stack(error), \
254 KERN_ERR \
255 "BTRFS: Transaction aborted (error %d)\n", \
256 (error))) { \
257 /* Stack trace printed. */ \
258 } else { \
259 btrfs_err((trans)->fs_info, \
260 "Transaction aborted (error %d)", \
261 (error)); \
262 } \
263 } \
264 __btrfs_abort_transaction((trans), __func__, \
265 __LINE__, (error), __first); \
266} while (0)
267
268int btrfs_end_transaction(struct btrfs_trans_handle *trans);
269struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
270 unsigned int num_items);
271struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
272 struct btrfs_root *root,
273 unsigned int num_items);
274struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
275struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root);
276struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root);
277struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root);
278struct btrfs_trans_handle *btrfs_attach_transaction_barrier(
279 struct btrfs_root *root);
280int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid);
281
282void btrfs_add_dead_root(struct btrfs_root *root);
283void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info);
284int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info);
285int btrfs_commit_transaction(struct btrfs_trans_handle *trans);
286void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans);
287int btrfs_commit_current_transaction(struct btrfs_root *root);
288int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans);
289bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans);
290void btrfs_throttle(struct btrfs_fs_info *fs_info);
291int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
292 struct btrfs_root *root);
293int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
294 struct extent_io_tree *dirty_pages, int mark);
295int btrfs_wait_tree_log_extents(struct btrfs_root *root, int mark);
296int btrfs_transaction_blocked(struct btrfs_fs_info *info);
297void btrfs_put_transaction(struct btrfs_transaction *transaction);
298void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
299 struct btrfs_root *root);
300void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans);
301void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
302 const char *function,
303 unsigned int line, int error, bool first_hit);
304
305int __init btrfs_transaction_init(void);
306void __cold btrfs_transaction_exit(void);
307
308#endif