xref: /linux/fs/btrfs/transaction.h (revision 0340dc4c82590d8735c58cf904a8aa1173273ab5)
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 #include "extent-io-tree.h"
18 #include "block-rsv.h"
19 #include "messages.h"
20 #include "misc.h"
21 
22 struct dentry;
23 struct inode;
24 struct btrfs_pending_snapshot;
25 struct btrfs_fs_info;
26 struct btrfs_root_item;
27 struct btrfs_root;
28 struct btrfs_path;
29 
30 /* Radix-tree tag for roots that are part of the trasaction. */
31 #define BTRFS_ROOT_TRANS_TAG			0
32 
33 enum btrfs_trans_state {
34 	TRANS_STATE_RUNNING,
35 	TRANS_STATE_COMMIT_PREP,
36 	TRANS_STATE_COMMIT_START,
37 	TRANS_STATE_COMMIT_DOING,
38 	TRANS_STATE_UNBLOCKED,
39 	TRANS_STATE_SUPER_COMMITTED,
40 	TRANS_STATE_COMPLETED,
41 	TRANS_STATE_MAX,
42 };
43 
44 #define BTRFS_TRANS_HAVE_FREE_BGS	0
45 #define BTRFS_TRANS_DIRTY_BG_RUN	1
46 #define BTRFS_TRANS_CACHE_ENOSPC	2
47 
48 struct btrfs_transaction {
49 	u64 transid;
50 	/*
51 	 * total external writers(USERSPACE/START/ATTACH) in this
52 	 * transaction, it must be zero before the transaction is
53 	 * being committed
54 	 */
55 	atomic_t num_extwriters;
56 	/*
57 	 * total writers in this transaction, it must be zero before the
58 	 * transaction can end
59 	 */
60 	atomic_t num_writers;
61 	refcount_t use_count;
62 
63 	unsigned long flags;
64 
65 	/* Be protected by fs_info->trans_lock when we want to change it. */
66 	enum btrfs_trans_state state;
67 	int aborted;
68 	struct list_head list;
69 	struct extent_io_tree dirty_pages;
70 	time64_t start_time;
71 	wait_queue_head_t writer_wait;
72 	wait_queue_head_t commit_wait;
73 	struct list_head pending_snapshots;
74 	struct list_head dev_update_list;
75 	struct list_head switch_commits;
76 	struct list_head dirty_bgs;
77 
78 	/*
79 	 * There is no explicit lock which protects io_bgs, rather its
80 	 * consistency is implied by the fact that all the sites which modify
81 	 * it do so under some form of transaction critical section, namely:
82 	 *
83 	 * - btrfs_start_dirty_block_groups - This function can only ever be
84 	 *   run by one of the transaction committers. Refer to
85 	 *   BTRFS_TRANS_DIRTY_BG_RUN usage in btrfs_commit_transaction
86 	 *
87 	 * - btrfs_write_dirty_blockgroups - this is called by
88 	 *   commit_cowonly_roots from transaction critical section
89 	 *   (TRANS_STATE_COMMIT_DOING)
90 	 *
91 	 * - btrfs_cleanup_dirty_bgs - called on transaction abort
92 	 */
93 	struct list_head io_bgs;
94 	struct list_head dropped_roots;
95 	struct extent_io_tree pinned_extents;
96 
97 	/*
98 	 * we need to make sure block group deletion doesn't race with
99 	 * free space cache writeout.  This mutex keeps them from stomping
100 	 * on each other
101 	 */
102 	struct mutex cache_write_mutex;
103 	spinlock_t dirty_bgs_lock;
104 	/* Protected by spin lock fs_info->unused_bgs_lock. */
105 	struct list_head deleted_bgs;
106 	spinlock_t dropped_roots_lock;
107 	struct btrfs_delayed_ref_root delayed_refs;
108 	struct btrfs_fs_info *fs_info;
109 
110 	/*
111 	 * Number of ordered extents the transaction must wait for before
112 	 * committing. These are ordered extents started by a fast fsync.
113 	 */
114 	atomic_t pending_ordered;
115 	wait_queue_head_t pending_wait;
116 };
117 
118 enum {
119 	ENUM_BIT(__TRANS_FREEZABLE),
120 	ENUM_BIT(__TRANS_START),
121 	ENUM_BIT(__TRANS_ATTACH),
122 	ENUM_BIT(__TRANS_JOIN),
123 	ENUM_BIT(__TRANS_JOIN_NOLOCK),
124 	ENUM_BIT(__TRANS_DUMMY),
125 	ENUM_BIT(__TRANS_JOIN_NOSTART),
126 };
127 
128 #define TRANS_START		(__TRANS_START | __TRANS_FREEZABLE)
129 #define TRANS_ATTACH		(__TRANS_ATTACH)
130 #define TRANS_JOIN		(__TRANS_JOIN | __TRANS_FREEZABLE)
131 #define TRANS_JOIN_NOLOCK	(__TRANS_JOIN_NOLOCK)
132 #define TRANS_JOIN_NOSTART	(__TRANS_JOIN_NOSTART)
133 
134 #define TRANS_EXTWRITERS	(__TRANS_START | __TRANS_ATTACH)
135 
136 struct btrfs_trans_handle {
137 	u64 transid;
138 	u64 bytes_reserved;
139 	u64 delayed_refs_bytes_reserved;
140 	u64 chunk_bytes_reserved;
141 	unsigned long delayed_ref_updates;
142 	unsigned long delayed_ref_csum_deletions;
143 	struct btrfs_transaction *transaction;
144 	struct btrfs_block_rsv *block_rsv;
145 	struct btrfs_block_rsv *orig_rsv;
146 	/* Set by a task that wants to create a snapshot. */
147 	struct btrfs_pending_snapshot *pending_snapshot;
148 	refcount_t use_count;
149 	unsigned int type;
150 	/*
151 	 * Error code of transaction abort, set outside of locks and must use
152 	 * the READ_ONCE/WRITE_ONCE access
153 	 */
154 	short aborted;
155 	bool adding_csums;
156 	bool allocating_chunk;
157 	bool removing_chunk;
158 	bool reloc_reserved;
159 	bool in_fsync;
160 	struct btrfs_fs_info *fs_info;
161 	struct list_head new_bgs;
162 	struct btrfs_block_rsv delayed_rsv;
163 };
164 
165 /*
166  * The abort status can be changed between calls and is not protected by locks.
167  * This accepts btrfs_transaction and btrfs_trans_handle as types. Once it's
168  * set to a non-zero value it does not change, so the macro should be in checks
169  * but is not necessary for further reads of the value.
170  */
171 #define TRANS_ABORTED(trans)		(unlikely(READ_ONCE((trans)->aborted)))
172 
173 struct btrfs_pending_snapshot {
174 	struct dentry *dentry;
175 	struct inode *dir;
176 	struct btrfs_root *root;
177 	struct btrfs_root_item *root_item;
178 	struct btrfs_root *snap;
179 	struct btrfs_qgroup_inherit *inherit;
180 	struct btrfs_path *path;
181 	/* block reservation for the operation */
182 	struct btrfs_block_rsv block_rsv;
183 	/* extra metadata reservation for relocation */
184 	int error;
185 	/* Preallocated anonymous block device number */
186 	dev_t anon_dev;
187 	bool readonly;
188 	struct list_head list;
189 };
190 
191 static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
192 					      struct btrfs_inode *inode)
193 {
194 	spin_lock(&inode->lock);
195 	inode->last_trans = trans->transaction->transid;
196 	inode->last_sub_trans = btrfs_get_root_log_transid(inode->root);
197 	inode->last_log_commit = inode->last_sub_trans - 1;
198 	spin_unlock(&inode->lock);
199 }
200 
201 /*
202  * Make qgroup codes to skip given qgroupid, means the old/new_roots for
203  * qgroup won't contain the qgroupid in it.
204  */
205 static inline void btrfs_set_skip_qgroup(struct btrfs_trans_handle *trans,
206 					 u64 qgroupid)
207 {
208 	struct btrfs_delayed_ref_root *delayed_refs;
209 
210 	delayed_refs = &trans->transaction->delayed_refs;
211 	WARN_ON(delayed_refs->qgroup_to_skip);
212 	delayed_refs->qgroup_to_skip = qgroupid;
213 }
214 
215 static inline void btrfs_clear_skip_qgroup(struct btrfs_trans_handle *trans)
216 {
217 	struct btrfs_delayed_ref_root *delayed_refs;
218 
219 	delayed_refs = &trans->transaction->delayed_refs;
220 	WARN_ON(!delayed_refs->qgroup_to_skip);
221 	delayed_refs->qgroup_to_skip = 0;
222 }
223 
224 bool __cold abort_should_print_stack(int error);
225 
226 /*
227  * Call btrfs_abort_transaction as early as possible when an error condition is
228  * detected, that way the exact stack trace is reported for some errors.
229  */
230 #define btrfs_abort_transaction(trans, error)		\
231 do {								\
232 	bool first = false;					\
233 	/* Report first abort since mount */			\
234 	if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,	\
235 			&((trans)->fs_info->fs_state))) {	\
236 		first = true;					\
237 		if (WARN(abort_should_print_stack(error),	\
238 			KERN_ERR				\
239 			"BTRFS: Transaction aborted (error %d)\n",	\
240 			(error))) {					\
241 			/* Stack trace printed. */			\
242 		} else {						\
243 			btrfs_err((trans)->fs_info,			\
244 				  "Transaction aborted (error %d)",	\
245 				  (error));			\
246 		}						\
247 	}							\
248 	__btrfs_abort_transaction((trans), __func__,		\
249 				  __LINE__, (error), first);	\
250 } while (0)
251 
252 int btrfs_end_transaction(struct btrfs_trans_handle *trans);
253 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
254 						   unsigned int num_items);
255 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
256 					struct btrfs_root *root,
257 					unsigned int num_items);
258 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
259 struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root);
260 struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root);
261 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root);
262 struct btrfs_trans_handle *btrfs_attach_transaction_barrier(
263 					struct btrfs_root *root);
264 int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid);
265 
266 void btrfs_add_dead_root(struct btrfs_root *root);
267 void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info);
268 int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info);
269 int btrfs_commit_transaction(struct btrfs_trans_handle *trans);
270 void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans);
271 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans);
272 bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans);
273 void btrfs_throttle(struct btrfs_fs_info *fs_info);
274 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
275 				struct btrfs_root *root);
276 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
277 				struct extent_io_tree *dirty_pages, int mark);
278 int btrfs_wait_tree_log_extents(struct btrfs_root *root, int mark);
279 int btrfs_transaction_blocked(struct btrfs_fs_info *info);
280 void btrfs_put_transaction(struct btrfs_transaction *transaction);
281 void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
282 			    struct btrfs_root *root);
283 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans);
284 void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
285 				      const char *function,
286 				      unsigned int line, int error, bool first_hit);
287 
288 int __init btrfs_transaction_init(void);
289 void __cold btrfs_transaction_exit(void);
290 
291 #endif
292