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d333327a SR |
1 | From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 |
2 | From: Stefan Reiter <s.reiter@proxmox.com> | |
3 | Date: Thu, 20 Aug 2020 14:25:00 +0200 | |
4 | Subject: [PATCH] PVE-Backup: Use a transaction to synchronize job states | |
5 | ||
6 | By using a JobTxn, we can sync dirty bitmaps only when *all* jobs were | |
7 | successful - meaning we don't need to remove them when the backup fails, | |
8 | since QEMU's BITMAP_SYNC_MODE_ON_SUCCESS will now handle that for us. | |
9 | ||
10 | To keep the rate-limiting and IO impact from before, we use a sequential | |
11 | transaction, so drives will still be backed up one after the other. | |
72ae34ec SR |
12 | |
13 | Signed-off-by: Stefan Reiter <s.reiter@proxmox.com> | |
d333327a SR |
14 | --- |
15 | pve-backup.c | 167 +++++++++++++++------------------------------------ | |
16 | 1 file changed, 49 insertions(+), 118 deletions(-) | |
17 | ||
18 | diff --git a/pve-backup.c b/pve-backup.c | |
817b7667 | 19 | index 1e7b92a950..f3df43eb8c 100644 |
d333327a SR |
20 | --- a/pve-backup.c |
21 | +++ b/pve-backup.c | |
22 | @@ -52,6 +52,7 @@ static struct PVEBackupState { | |
23 | VmaWriter *vmaw; | |
24 | ProxmoxBackupHandle *pbs; | |
25 | GList *di_list; | |
26 | + JobTxn *txn; | |
27 | QemuMutex backup_mutex; | |
28 | CoMutex dump_callback_mutex; | |
29 | } backup_state; | |
30 | @@ -71,32 +72,12 @@ typedef struct PVEBackupDevInfo { | |
31 | size_t size; | |
32 | uint64_t block_size; | |
33 | uint8_t dev_id; | |
34 | - bool completed; | |
35 | char targetfile[PATH_MAX]; | |
36 | BdrvDirtyBitmap *bitmap; | |
37 | BlockDriverState *target; | |
38 | + BlockJob *job; | |
39 | } PVEBackupDevInfo; | |
40 | ||
41 | -static void pvebackup_run_next_job(void); | |
42 | - | |
43 | -static BlockJob * | |
44 | -lookup_active_block_job(PVEBackupDevInfo *di) | |
45 | -{ | |
46 | - if (!di->completed && di->bs) { | |
47 | - for (BlockJob *job = block_job_next(NULL); job; job = block_job_next(job)) { | |
48 | - if (job->job.driver->job_type != JOB_TYPE_BACKUP) { | |
49 | - continue; | |
50 | - } | |
51 | - | |
52 | - BackupBlockJob *bjob = container_of(job, BackupBlockJob, common); | |
53 | - if (bjob && bjob->source_bs == di->bs) { | |
54 | - return job; | |
55 | - } | |
56 | - } | |
57 | - } | |
58 | - return NULL; | |
59 | -} | |
60 | - | |
61 | static void pvebackup_propagate_error(Error *err) | |
62 | { | |
63 | qemu_mutex_lock(&backup_state.stat.lock); | |
64 | @@ -272,18 +253,6 @@ static void coroutine_fn pvebackup_co_cleanup(void *unused) | |
65 | if (local_err != NULL) { | |
66 | pvebackup_propagate_error(local_err); | |
67 | } | |
68 | - } else { | |
69 | - // on error or cancel we cannot ensure synchronization of dirty | |
70 | - // bitmaps with backup server, so remove all and do full backup next | |
71 | - GList *l = backup_state.di_list; | |
72 | - while (l) { | |
73 | - PVEBackupDevInfo *di = (PVEBackupDevInfo *)l->data; | |
74 | - l = g_list_next(l); | |
75 | - | |
76 | - if (di->bitmap) { | |
77 | - bdrv_release_dirty_bitmap(di->bitmap); | |
78 | - } | |
79 | - } | |
80 | } | |
81 | ||
82 | proxmox_backup_disconnect(backup_state.pbs); | |
83 | @@ -322,8 +291,6 @@ static void pvebackup_complete_cb(void *opaque, int ret) | |
84 | ||
85 | qemu_mutex_lock(&backup_state.backup_mutex); | |
86 | ||
87 | - di->completed = true; | |
88 | - | |
89 | if (ret < 0) { | |
90 | Error *local_err = NULL; | |
91 | error_setg(&local_err, "job failed with err %d - %s", ret, strerror(-ret)); | |
92 | @@ -336,20 +303,17 @@ static void pvebackup_complete_cb(void *opaque, int ret) | |
93 | ||
94 | block_on_coroutine_fn(pvebackup_complete_stream, di); | |
95 | ||
96 | - // remove self from job queue | |
97 | + // remove self from job list | |
98 | backup_state.di_list = g_list_remove(backup_state.di_list, di); | |
99 | ||
100 | - if (di->bitmap && ret < 0) { | |
101 | - // on error or cancel we cannot ensure synchronization of dirty | |
102 | - // bitmaps with backup server, so remove all and do full backup next | |
103 | - bdrv_release_dirty_bitmap(di->bitmap); | |
104 | - } | |
105 | - | |
106 | g_free(di); | |
107 | ||
108 | - qemu_mutex_unlock(&backup_state.backup_mutex); | |
109 | + /* call cleanup if we're the last job */ | |
110 | + if (!g_list_first(backup_state.di_list)) { | |
111 | + block_on_coroutine_fn(pvebackup_co_cleanup, NULL); | |
112 | + } | |
113 | ||
114 | - pvebackup_run_next_job(); | |
115 | + qemu_mutex_unlock(&backup_state.backup_mutex); | |
116 | } | |
117 | ||
118 | static void pvebackup_cancel(void) | |
119 | @@ -371,36 +335,28 @@ static void pvebackup_cancel(void) | |
120 | proxmox_backup_abort(backup_state.pbs, "backup canceled"); | |
121 | } | |
122 | ||
123 | - qemu_mutex_unlock(&backup_state.backup_mutex); | |
124 | - | |
125 | - for(;;) { | |
126 | - | |
127 | - BlockJob *next_job = NULL; | |
128 | - | |
129 | - qemu_mutex_lock(&backup_state.backup_mutex); | |
130 | - | |
131 | - GList *l = backup_state.di_list; | |
132 | - while (l) { | |
133 | - PVEBackupDevInfo *di = (PVEBackupDevInfo *)l->data; | |
134 | - l = g_list_next(l); | |
135 | + /* it's enough to cancel one job in the transaction, the rest will follow | |
136 | + * automatically */ | |
137 | + GList *bdi = g_list_first(backup_state.di_list); | |
138 | + BlockJob *cancel_job = bdi && bdi->data ? | |
139 | + ((PVEBackupDevInfo *)bdi->data)->job : | |
140 | + NULL; | |
141 | ||
142 | - BlockJob *job = lookup_active_block_job(di); | |
143 | - if (job != NULL) { | |
144 | - next_job = job; | |
145 | - break; | |
146 | - } | |
147 | - } | |
148 | + /* ref the job before releasing the mutex, just to be safe */ | |
149 | + if (cancel_job) { | |
150 | + job_ref(&cancel_job->job); | |
151 | + } | |
152 | ||
153 | - qemu_mutex_unlock(&backup_state.backup_mutex); | |
154 | + /* job_cancel_sync may enter the job, so we need to release the | |
155 | + * backup_mutex to avoid deadlock */ | |
156 | + qemu_mutex_unlock(&backup_state.backup_mutex); | |
157 | ||
158 | - if (next_job) { | |
159 | - AioContext *aio_context = next_job->job.aio_context; | |
160 | - aio_context_acquire(aio_context); | |
161 | - job_cancel_sync(&next_job->job); | |
162 | - aio_context_release(aio_context); | |
163 | - } else { | |
164 | - break; | |
165 | - } | |
166 | + if (cancel_job) { | |
167 | + AioContext *aio_context = cancel_job->job.aio_context; | |
168 | + aio_context_acquire(aio_context); | |
169 | + job_cancel_sync(&cancel_job->job); | |
170 | + job_unref(&cancel_job->job); | |
171 | + aio_context_release(aio_context); | |
172 | } | |
173 | } | |
174 | ||
175 | @@ -459,51 +415,19 @@ static int coroutine_fn pvebackup_co_add_config( | |
176 | goto out; | |
177 | } | |
178 | ||
179 | -bool job_should_pause(Job *job); | |
180 | - | |
181 | -static void pvebackup_run_next_job(void) | |
182 | -{ | |
183 | - assert(!qemu_in_coroutine()); | |
184 | - | |
185 | - qemu_mutex_lock(&backup_state.backup_mutex); | |
186 | - | |
187 | - GList *l = backup_state.di_list; | |
188 | - while (l) { | |
189 | - PVEBackupDevInfo *di = (PVEBackupDevInfo *)l->data; | |
190 | - l = g_list_next(l); | |
191 | - | |
192 | - BlockJob *job = lookup_active_block_job(di); | |
193 | - | |
194 | - if (job) { | |
195 | - qemu_mutex_unlock(&backup_state.backup_mutex); | |
196 | - | |
197 | - AioContext *aio_context = job->job.aio_context; | |
198 | - aio_context_acquire(aio_context); | |
199 | - | |
200 | - if (job_should_pause(&job->job)) { | |
201 | - bool error_or_canceled = pvebackup_error_or_canceled(); | |
202 | - if (error_or_canceled) { | |
203 | - job_cancel_sync(&job->job); | |
204 | - } else { | |
205 | - job_resume(&job->job); | |
206 | - } | |
207 | - } | |
208 | - aio_context_release(aio_context); | |
209 | - return; | |
210 | - } | |
211 | - } | |
212 | - | |
213 | - block_on_coroutine_fn(pvebackup_co_cleanup, NULL); // no more jobs, run cleanup | |
214 | - | |
215 | - qemu_mutex_unlock(&backup_state.backup_mutex); | |
216 | -} | |
217 | - | |
218 | static bool create_backup_jobs(void) { | |
219 | ||
220 | assert(!qemu_in_coroutine()); | |
221 | ||
222 | Error *local_err = NULL; | |
223 | ||
224 | + /* create job transaction to synchronize bitmap commit and cancel all | |
225 | + * jobs in case one errors */ | |
226 | + if (backup_state.txn) { | |
227 | + job_txn_unref(backup_state.txn); | |
228 | + } | |
229 | + backup_state.txn = job_txn_new_seq(); | |
230 | + | |
231 | /* create and start all jobs (paused state) */ | |
232 | GList *l = backup_state.di_list; | |
233 | while (l) { | |
234 | @@ -524,7 +448,7 @@ static bool create_backup_jobs(void) { | |
235 | BlockJob *job = backup_job_create( | |
236 | NULL, di->bs, di->target, backup_state.speed, sync_mode, di->bitmap, | |
237 | bitmap_mode, false, NULL, BLOCKDEV_ON_ERROR_REPORT, BLOCKDEV_ON_ERROR_REPORT, | |
238 | - JOB_DEFAULT, pvebackup_complete_cb, di, 1, NULL, &local_err); | |
239 | + JOB_DEFAULT, pvebackup_complete_cb, di, backup_state.txn, &local_err); | |
240 | ||
241 | aio_context_release(aio_context); | |
242 | ||
243 | @@ -536,7 +460,8 @@ static bool create_backup_jobs(void) { | |
244 | pvebackup_propagate_error(create_job_err); | |
245 | break; | |
246 | } | |
247 | - job_start(&job->job); | |
248 | + | |
249 | + di->job = job; | |
250 | ||
251 | bdrv_unref(di->target); | |
252 | di->target = NULL; | |
253 | @@ -554,6 +479,10 @@ static bool create_backup_jobs(void) { | |
254 | bdrv_unref(di->target); | |
255 | di->target = NULL; | |
256 | } | |
257 | + | |
258 | + if (di->job) { | |
259 | + job_unref(&di->job->job); | |
260 | + } | |
261 | } | |
262 | } | |
263 | ||
264 | @@ -944,10 +873,6 @@ err: | |
265 | PVEBackupDevInfo *di = (PVEBackupDevInfo *)l->data; | |
266 | l = g_list_next(l); | |
267 | ||
268 | - if (di->bitmap) { | |
269 | - bdrv_release_dirty_bitmap(di->bitmap); | |
270 | - } | |
271 | - | |
272 | if (di->target) { | |
273 | bdrv_unref(di->target); | |
274 | } | |
275 | @@ -1036,9 +961,15 @@ UuidInfo *qmp_backup( | |
276 | block_on_coroutine_fn(pvebackup_co_prepare, &task); | |
277 | ||
278 | if (*errp == NULL) { | |
279 | - create_backup_jobs(); | |
280 | + bool errors = create_backup_jobs(); | |
281 | qemu_mutex_unlock(&backup_state.backup_mutex); | |
282 | - pvebackup_run_next_job(); | |
283 | + | |
284 | + if (!errors) { | |
285 | + /* start the first job in the transaction | |
286 | + * note: this might directly enter the job, so we need to do this | |
287 | + * after unlocking the backup_mutex */ | |
288 | + job_txn_start_seq(backup_state.txn); | |
289 | + } | |
290 | } else { | |
291 | qemu_mutex_unlock(&backup_state.backup_mutex); | |
292 | } |