#define BACKUP_CLUSTER_SIZE_DEFAULT (1 << 16)
+typedef struct CowRequest {
+ int64_t start_byte;
+ int64_t end_byte;
+ QLIST_ENTRY(CowRequest) list;
+ CoQueue wait_queue; /* coroutines blocked on this request */
+} CowRequest;
+
typedef struct BackupBlockJob {
BlockJob common;
BlockBackend *target;
HBitmap *copy_bitmap;
bool use_copy_range;
int64_t copy_range_size;
+
+ bool serialize_target_writes;
} BackupBlockJob;
static const BlockJobDriver backup_job_driver;
}
/* Copy range to target with a bounce buffer and return the bytes copied. If
- * error occured, return a negative error number */
+ * error occurred, return a negative error number */
static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job,
int64_t start,
int64_t end,
QEMUIOVector qiov;
BlockBackend *blk = job->common.blk;
int nbytes;
+ int read_flags = is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0;
+ int write_flags = job->serialize_target_writes ? BDRV_REQ_SERIALISING : 0;
hbitmap_reset(job->copy_bitmap, start / job->cluster_size, 1);
nbytes = MIN(job->cluster_size, job->len - start);
iov.iov_len = nbytes;
qemu_iovec_init_external(&qiov, &iov, 1);
- ret = blk_co_preadv(blk, start, qiov.size, &qiov,
- is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
+ ret = blk_co_preadv(blk, start, qiov.size, &qiov, read_flags);
if (ret < 0) {
trace_backup_do_cow_read_fail(job, start, ret);
if (error_is_read) {
if (qemu_iovec_is_zero(&qiov)) {
ret = blk_co_pwrite_zeroes(job->target, start,
- qiov.size, BDRV_REQ_MAY_UNMAP);
+ qiov.size, write_flags | BDRV_REQ_MAY_UNMAP);
} else {
ret = blk_co_pwritev(job->target, start,
- qiov.size, &qiov,
- job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0);
+ qiov.size, &qiov, write_flags |
+ (job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0));
}
if (ret < 0) {
trace_backup_do_cow_write_fail(job, start, ret);
}
-/* Copy range to target and return the bytes copied. If error occured, return a
+/* Copy range to target and return the bytes copied. If error occurred, return a
* negative error number. */
static int coroutine_fn backup_cow_with_offload(BackupBlockJob *job,
int64_t start,
int nr_clusters;
BlockBackend *blk = job->common.blk;
int nbytes;
+ int read_flags = is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0;
+ int write_flags = job->serialize_target_writes ? BDRV_REQ_SERIALISING : 0;
assert(QEMU_IS_ALIGNED(job->copy_range_size, job->cluster_size));
nbytes = MIN(job->copy_range_size, end - start);
hbitmap_reset(job->copy_bitmap, start / job->cluster_size,
nr_clusters);
ret = blk_co_copy_range(blk, start, job->target, start, nbytes,
- is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
+ read_flags, write_flags);
if (ret < 0) {
trace_backup_do_cow_copy_range_fail(job, start, ret);
hbitmap_set(job->copy_bitmap, start / job->cluster_size,
hbitmap_set(backup_job->copy_bitmap, 0, len);
}
-void backup_wait_for_overlapping_requests(BlockJob *job, int64_t offset,
- uint64_t bytes)
-{
- BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
- int64_t start, end;
-
- assert(block_job_driver(job) == &backup_job_driver);
-
- start = QEMU_ALIGN_DOWN(offset, backup_job->cluster_size);
- end = QEMU_ALIGN_UP(offset + bytes, backup_job->cluster_size);
- wait_for_overlapping_requests(backup_job, start, end);
-}
-
-void backup_cow_request_begin(CowRequest *req, BlockJob *job,
- int64_t offset, uint64_t bytes)
-{
- BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
- int64_t start, end;
-
- assert(block_job_driver(job) == &backup_job_driver);
-
- start = QEMU_ALIGN_DOWN(offset, backup_job->cluster_size);
- end = QEMU_ALIGN_UP(offset + bytes, backup_job->cluster_size);
- cow_request_begin(req, backup_job, start, end);
-}
-
-void backup_cow_request_end(CowRequest *req)
-{
- cow_request_end(req);
-}
-
static void backup_drain(BlockJob *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common);
}
}
-typedef struct {
- int ret;
-} BackupCompleteData;
-
-static void backup_complete(Job *job, void *opaque)
-{
- BackupCompleteData *data = opaque;
-
- job_completed(job, data->ret, NULL);
- g_free(data);
-}
-
static bool coroutine_fn yield_and_check(BackupBlockJob *job)
{
uint64_t delay_ns;
HBitmapIter hbi;
hbitmap_iter_init(&hbi, job->copy_bitmap, 0);
- while ((cluster = hbitmap_iter_next(&hbi, true)) != -1) {
+ while ((cluster = hbitmap_iter_next(&hbi)) != -1) {
do {
if (yield_and_check(job)) {
return 0;
break;
}
- offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset);
+ offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset,
+ UINT64_MAX);
if (offset == -1) {
hbitmap_set(job->copy_bitmap, cluster, end - cluster);
break;
bdrv_dirty_iter_free(dbi);
}
-static void coroutine_fn backup_run(void *opaque)
+static int coroutine_fn backup_run(Job *job, Error **errp)
{
- BackupBlockJob *job = opaque;
- BackupCompleteData *data;
- BlockDriverState *bs = blk_bs(job->common.blk);
+ BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
+ BlockDriverState *bs = blk_bs(s->common.blk);
int64_t offset, nb_clusters;
int ret = 0;
- QLIST_INIT(&job->inflight_reqs);
- qemu_co_rwlock_init(&job->flush_rwlock);
+ QLIST_INIT(&s->inflight_reqs);
+ qemu_co_rwlock_init(&s->flush_rwlock);
- nb_clusters = DIV_ROUND_UP(job->len, job->cluster_size);
- job_progress_set_remaining(&job->common.job, job->len);
+ nb_clusters = DIV_ROUND_UP(s->len, s->cluster_size);
+ job_progress_set_remaining(job, s->len);
- job->copy_bitmap = hbitmap_alloc(nb_clusters, 0);
- if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
- backup_incremental_init_copy_bitmap(job);
+ s->copy_bitmap = hbitmap_alloc(nb_clusters, 0);
+ if (s->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
+ backup_incremental_init_copy_bitmap(s);
} else {
- hbitmap_set(job->copy_bitmap, 0, nb_clusters);
+ hbitmap_set(s->copy_bitmap, 0, nb_clusters);
}
- job->before_write.notify = backup_before_write_notify;
- bdrv_add_before_write_notifier(bs, &job->before_write);
+ s->before_write.notify = backup_before_write_notify;
+ bdrv_add_before_write_notifier(bs, &s->before_write);
- if (job->sync_mode == MIRROR_SYNC_MODE_NONE) {
+ if (s->sync_mode == MIRROR_SYNC_MODE_NONE) {
/* All bits are set in copy_bitmap to allow any cluster to be copied.
* This does not actually require them to be copied. */
- while (!job_is_cancelled(&job->common.job)) {
+ while (!job_is_cancelled(job)) {
/* Yield until the job is cancelled. We just let our before_write
* notify callback service CoW requests. */
- job_yield(&job->common.job);
+ job_yield(job);
}
- } else if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
- ret = backup_run_incremental(job);
+ } else if (s->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
+ ret = backup_run_incremental(s);
} else {
/* Both FULL and TOP SYNC_MODE's require copying.. */
- for (offset = 0; offset < job->len;
- offset += job->cluster_size) {
+ for (offset = 0; offset < s->len;
+ offset += s->cluster_size) {
bool error_is_read;
int alloced = 0;
- if (yield_and_check(job)) {
+ if (yield_and_check(s)) {
break;
}
- if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
+ if (s->sync_mode == MIRROR_SYNC_MODE_TOP) {
int i;
int64_t n;
/* Check to see if these blocks are already in the
* backing file. */
- for (i = 0; i < job->cluster_size;) {
+ for (i = 0; i < s->cluster_size;) {
/* bdrv_is_allocated() only returns true/false based
* on the first set of sectors it comes across that
* are are all in the same state.
* needed but at some point that is always the case. */
alloced =
bdrv_is_allocated(bs, offset + i,
- job->cluster_size - i, &n);
+ s->cluster_size - i, &n);
i += n;
if (alloced || n == 0) {
if (alloced < 0) {
ret = alloced;
} else {
- ret = backup_do_cow(job, offset, job->cluster_size,
+ ret = backup_do_cow(s, offset, s->cluster_size,
&error_is_read, false);
}
if (ret < 0) {
/* Depending on error action, fail now or retry cluster */
BlockErrorAction action =
- backup_error_action(job, error_is_read, -ret);
+ backup_error_action(s, error_is_read, -ret);
if (action == BLOCK_ERROR_ACTION_REPORT) {
break;
} else {
- offset -= job->cluster_size;
+ offset -= s->cluster_size;
continue;
}
}
}
}
- notifier_with_return_remove(&job->before_write);
+ notifier_with_return_remove(&s->before_write);
/* wait until pending backup_do_cow() calls have completed */
- qemu_co_rwlock_wrlock(&job->flush_rwlock);
- qemu_co_rwlock_unlock(&job->flush_rwlock);
- hbitmap_free(job->copy_bitmap);
+ qemu_co_rwlock_wrlock(&s->flush_rwlock);
+ qemu_co_rwlock_unlock(&s->flush_rwlock);
+ hbitmap_free(s->copy_bitmap);
- data = g_malloc(sizeof(*data));
- data->ret = ret;
- job_defer_to_main_loop(&job->common.job, backup_complete, data);
+ return ret;
}
static const BlockJobDriver backup_job_driver = {
.free = block_job_free,
.user_resume = block_job_user_resume,
.drain = block_job_drain,
- .start = backup_run,
+ .run = backup_run,
.commit = backup_commit,
.abort = backup_abort,
.clean = backup_clean,
sync_bitmap : NULL;
job->compress = compress;
+ /* Detect image-fleecing (and similar) schemes */
+ job->serialize_target_writes = bdrv_chain_contains(target, bs);
+
/* If there is no backing file on the target, we cannot rely on COW if our
* backup cluster size is smaller than the target cluster size. Even for
* targets with a backing file, try to avoid COW if possible. */
projects / qemu.git / blobdiff