1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
|
#include <linux/module.h>
#include <linux/fs.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
static int total_trans = 0;
extern struct kmem_cache *btrfs_trans_handle_cachep;
extern struct kmem_cache *btrfs_transaction_cachep;
#define TRANS_MAGIC 0xE1E10E
static void put_transaction(struct btrfs_transaction *transaction)
{
WARN_ON(transaction->use_count == 0);
transaction->use_count--;
WARN_ON(transaction->magic != TRANS_MAGIC);
if (transaction->use_count == 0) {
WARN_ON(total_trans == 0);
total_trans--;
memset(transaction, 0, sizeof(*transaction));
kmem_cache_free(btrfs_transaction_cachep, transaction);
}
}
static int join_transaction(struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans;
cur_trans = root->fs_info->running_transaction;
if (!cur_trans) {
cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
GFP_NOFS);
total_trans++;
BUG_ON(!cur_trans);
root->fs_info->running_transaction = cur_trans;
cur_trans->num_writers = 0;
cur_trans->transid = root->root_key.offset + 1;
init_waitqueue_head(&cur_trans->writer_wait);
init_waitqueue_head(&cur_trans->commit_wait);
cur_trans->magic = TRANS_MAGIC;
cur_trans->in_commit = 0;
cur_trans->use_count = 1;
cur_trans->commit_done = 0;
}
cur_trans->num_writers++;
return 0;
}
struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
int num_blocks)
{
struct btrfs_trans_handle *h =
kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
int ret;
/* FIXME, use the right root */
root = root->fs_info->fs_root;
mutex_lock(&root->fs_info->trans_mutex);
ret = join_transaction(root);
BUG_ON(ret);
h->transid = root->fs_info->running_transaction->transid;
h->transaction = root->fs_info->running_transaction;
h->blocks_reserved = num_blocks;
h->blocks_used = 0;
root->fs_info->running_transaction->use_count++;
mutex_unlock(&root->fs_info->trans_mutex);
h->magic = h->magic2 = TRANS_MAGIC;
return h;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans;
/* FIXME, use the right root */
root = root->fs_info->fs_root;
WARN_ON(trans->magic != TRANS_MAGIC);
WARN_ON(trans->magic2 != TRANS_MAGIC);
mutex_lock(&root->fs_info->trans_mutex);
cur_trans = root->fs_info->running_transaction;
WARN_ON(cur_trans->num_writers < 1);
if (waitqueue_active(&cur_trans->writer_wait))
wake_up(&cur_trans->writer_wait);
cur_trans->num_writers--;
put_transaction(cur_trans);
mutex_unlock(&root->fs_info->trans_mutex);
memset(trans, 0, sizeof(*trans));
kmem_cache_free(btrfs_trans_handle_cachep, trans);
return 0;
}
int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
filemap_write_and_wait(root->fs_info->btree_inode->i_mapping);
return 0;
}
int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
u64 old_extent_block;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *extent_root = fs_info->extent_root;
struct btrfs_root *inode_root = fs_info->inode_root;
btrfs_set_root_blocknr(&inode_root->root_item,
inode_root->node->b_blocknr);
ret = btrfs_update_root(trans, tree_root,
&inode_root->root_key,
&inode_root->root_item);
BUG_ON(ret);
while(1) {
old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
if (old_extent_block == extent_root->node->b_blocknr)
break;
btrfs_set_root_blocknr(&extent_root->root_item,
extent_root->node->b_blocknr);
ret = btrfs_update_root(trans, tree_root,
&extent_root->root_key,
&extent_root->root_item);
BUG_ON(ret);
}
return 0;
}
static int wait_for_commit(struct btrfs_root *root,
struct btrfs_transaction *commit)
{
DEFINE_WAIT(wait);
while(!commit->commit_done) {
prepare_to_wait(&commit->commit_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (commit->commit_done)
break;
mutex_unlock(&root->fs_info->trans_mutex);
schedule();
mutex_lock(&root->fs_info->trans_mutex);
}
finish_wait(&commit->commit_wait, &wait);
return 0;
}
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret = 0;
struct buffer_head *snap;
struct btrfs_key snap_key;
struct btrfs_transaction *cur_trans;
DEFINE_WAIT(wait);
/* FIXME, use the right root */
root = root->fs_info->fs_root;
mutex_lock(&root->fs_info->trans_mutex);
if (trans->transaction->in_commit) {
printk("already in commit!, waiting\n");
cur_trans = trans->transaction;
trans->transaction->use_count++;
btrfs_end_transaction(trans, root);
ret = wait_for_commit(root, cur_trans);
BUG_ON(ret);
put_transaction(cur_trans);
mutex_unlock(&root->fs_info->trans_mutex);
return 0;
}
cur_trans = trans->transaction;
trans->transaction->in_commit = 1;
while (trans->transaction->num_writers > 1) {
WARN_ON(cur_trans != trans->transaction);
prepare_to_wait(&trans->transaction->writer_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (trans->transaction->num_writers <= 1)
break;
mutex_unlock(&root->fs_info->trans_mutex);
schedule();
mutex_lock(&root->fs_info->trans_mutex);
finish_wait(&trans->transaction->writer_wait, &wait);
}
finish_wait(&trans->transaction->writer_wait, &wait);
WARN_ON(cur_trans != trans->transaction);
if (root->node != root->commit_root) {
memcpy(&snap_key, &root->root_key, sizeof(snap_key));
root->root_key.offset++;
}
if (btrfs_root_blocknr(&root->root_item) != root->node->b_blocknr) {
btrfs_set_root_blocknr(&root->root_item, root->node->b_blocknr);
ret = btrfs_insert_root(trans, root->fs_info->tree_root,
&root->root_key, &root->root_item);
BUG_ON(ret);
}
ret = btrfs_commit_tree_roots(trans, root);
BUG_ON(ret);
cur_trans = root->fs_info->running_transaction;
root->fs_info->running_transaction = NULL;
mutex_unlock(&root->fs_info->trans_mutex);
ret = btrfs_write_and_wait_transaction(trans, root);
BUG_ON(ret);
write_ctree_super(trans, root);
btrfs_finish_extent_commit(trans, root);
mutex_lock(&root->fs_info->trans_mutex);
cur_trans->commit_done = 1;
wake_up(&cur_trans->commit_wait);
put_transaction(cur_trans);
put_transaction(cur_trans);
mutex_unlock(&root->fs_info->trans_mutex);
kmem_cache_free(btrfs_trans_handle_cachep, trans);
if (root->node != root->commit_root) {
trans = btrfs_start_transaction(root, 1);
snap = root->commit_root;
root->commit_root = root->node;
get_bh(root->node);
ret = btrfs_drop_snapshot(trans, root, snap);
BUG_ON(ret);
ret = btrfs_del_root(trans, root->fs_info->tree_root,
&snap_key);
BUG_ON(ret);
root->fs_info->generation = root->root_key.offset + 1;
ret = btrfs_end_transaction(trans, root);
BUG_ON(ret);
}
return ret;
}
|
