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block/backup: deal with zero detection

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We have detect_zeroes option, so at least for blockdev-backup user
should define it if zero-detection is needed. For drive-backup leave
detection enabled by default but do it through existing option instead
of open-coding.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190730163251.755248-2-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
Chen Qun 2019-07-30 19:32:49 +03:00
parent 19b6914ef5
commit 6751482910
1 changed files with 83 additions and 0 deletions
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block-backup-deal-with-zero-detection.patch Normal file
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@ -0,0 +1,83 @@
From 3cf14b9a7daf0a40eb2af7a86e67cb05f6d2bea6 Mon Sep 17 00:00:00 2001
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Date: Tue, 30 Jul 2019 19:32:49 +0300
Subject: [PATCH] block/backup: deal with zero detection
We have detect_zeroes option, so at least for blockdev-backup user
should define it if zero-detection is needed. For drive-backup leave
detection enabled by default but do it through existing option instead
of open-coding.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190730163251.755248-2-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>
---
block/backup.c | 15 ++++++---------
blockdev.c | 8 ++++----
2 files changed, 10 insertions(+), 13 deletions(-)
diff --git a/block/backup.c b/block/backup.c
index cc19643b47..6023573299 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -110,7 +110,10 @@ static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job,
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;
+ int write_flags =
+ (job->serialize_target_writes ? BDRV_REQ_SERIALISING : 0) |
+ (job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0);
+
assert(QEMU_IS_ALIGNED(start, job->cluster_size));
hbitmap_reset(job->copy_bitmap, start, job->cluster_size);
@@ -128,14 +131,8 @@ static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job,
goto fail;
}
- if (buffer_is_zero(*bounce_buffer, nbytes)) {
- ret = blk_co_pwrite_zeroes(job->target, start,
- nbytes, write_flags | BDRV_REQ_MAY_UNMAP);
- } else {
- ret = blk_co_pwrite(job->target, start,
- nbytes, *bounce_buffer, write_flags |
- (job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0));
- }
+ ret = blk_co_pwrite(job->target, start, nbytes, *bounce_buffer,
+ write_flags);
if (ret < 0) {
trace_backup_do_cow_write_fail(job, start, ret);
if (error_is_read) {
diff --git a/blockdev.c b/blockdev.c
index 0a71a15fa2..94e5aee30b 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3572,7 +3572,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
BlockDriverState *source = NULL;
BlockJob *job = NULL;
AioContext *aio_context;
- QDict *options = NULL;
+ QDict *options;
Error *local_err = NULL;
int flags;
int64_t size;
@@ -3645,10 +3645,10 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
goto out;
}
+ options = qdict_new();
+ qdict_put_str(options, "discard", "unmap");
+ qdict_put_str(options, "detect-zeroes", "unmap");
if (backup->format) {
- if (!options) {
- options = qdict_new();
- }
qdict_put_str(options, "driver", backup->format);
}
--
2.27.0