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Backup: don't do copy-on-read in before_write_notifier 

We will copy data in before_write_notifier to do backup.
It is a nested I/O request, so we cannot do copy-on-read.

The steps to reproduce it:
1. -drive copy-on-read=on,...  // qemu option
2. drive_backup -f disk0 /path_to_backup.img // monitor command

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Tested-by: Jeff Cody <jcody@redhat.com>
Message-id: 1441682913-14320-3-git-send-email-wency@cn.fujitsu.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
This commit is contained in:
Wen Congyang 2015-09-08 11:28:33 +08:00 committed by Jeff Cody
parent 9568b511c9
commit 06c3916b35
1 changed files with 14 additions and 6 deletions
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16
block/backup.c
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@ -89,7 +89,8 @@ static void cow_request_end(CowRequest *req)
static int coroutine_fn backup_do_cow(BlockDriverState *bs, static int coroutine_fn backup_do_cow(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int64_t sector_num, int nb_sectors,
bool *error_is_read) bool *error_is_read,
bool is_write_notifier)
{ {
BackupBlockJob *job = (BackupBlockJob *)bs->job; BackupBlockJob *job = (BackupBlockJob *)bs->job;
CowRequest cow_request; CowRequest cow_request;
@ -129,8 +130,14 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs,
iov.iov_len = n * BDRV_SECTOR_SIZE; iov.iov_len = n * BDRV_SECTOR_SIZE;
qemu_iovec_init_external(&bounce_qiov, &iov, 1); qemu_iovec_init_external(&bounce_qiov, &iov, 1);
if (is_write_notifier) {
ret = bdrv_co_no_copy_on_readv(bs,
start * BACKUP_SECTORS_PER_CLUSTER,
n, &bounce_qiov);
} else {
ret = bdrv_co_readv(bs, start * BACKUP_SECTORS_PER_CLUSTER, n, ret = bdrv_co_readv(bs, start * BACKUP_SECTORS_PER_CLUSTER, n,
&bounce_qiov); &bounce_qiov);
}
if (ret < 0) { if (ret < 0) {
trace_backup_do_cow_read_fail(job, start, ret); trace_backup_do_cow_read_fail(job, start, ret);
if (error_is_read) { if (error_is_read) {
@ -190,7 +197,7 @@ static int coroutine_fn backup_before_write_notify(
assert((req->offset & (BDRV_SECTOR_SIZE - 1)) == 0); assert((req->offset & (BDRV_SECTOR_SIZE - 1)) == 0);
assert((req->bytes & (BDRV_SECTOR_SIZE - 1)) == 0); assert((req->bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
return backup_do_cow(req->bs, sector_num, nb_sectors, NULL); return backup_do_cow(req->bs, sector_num, nb_sectors, NULL, true);
} }
static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp) static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp)
@ -303,7 +310,8 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
return ret; return ret;
} }
ret = backup_do_cow(bs, cluster * BACKUP_SECTORS_PER_CLUSTER, ret = backup_do_cow(bs, cluster * BACKUP_SECTORS_PER_CLUSTER,
BACKUP_SECTORS_PER_CLUSTER, &error_is_read); BACKUP_SECTORS_PER_CLUSTER, &error_is_read,
false);
if ((ret < 0) && if ((ret < 0) &&
backup_error_action(job, error_is_read, -ret) == backup_error_action(job, error_is_read, -ret) ==
BLOCK_ERROR_ACTION_REPORT) { BLOCK_ERROR_ACTION_REPORT) {
@ -408,7 +416,7 @@ static void coroutine_fn backup_run(void *opaque)
} }
/* FULL sync mode we copy the whole drive. */ /* FULL sync mode we copy the whole drive. */
ret = backup_do_cow(bs, start * BACKUP_SECTORS_PER_CLUSTER, ret = backup_do_cow(bs, start * BACKUP_SECTORS_PER_CLUSTER,
BACKUP_SECTORS_PER_CLUSTER, &error_is_read); BACKUP_SECTORS_PER_CLUSTER, &error_is_read, false);
if (ret < 0) { if (ret < 0) {
/* Depending on error action, fail now or retry cluster */ /* Depending on error action, fail now or retry cluster */
BlockErrorAction action = BlockErrorAction action =