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authorJohn Snow <jsnow@redhat.com>2019-07-29 16:35:55 -0400
committerJohn Snow <jsnow@redhat.com>2019-08-16 18:29:43 -0400
commit1a2b8b406bea1108c990b6fc932bef63211de245 (patch)
tree2a0b4bee023b25558b457297116890a26e179de8 /blockdev.c
parent7e30dd618ebfe3ab1ed54f2e98ba75d799c0be20 (diff)
block/backup: support bitmap sync modes for non-bitmap backups
Accept bitmaps and sync policies for the other backup modes. This allows us to do things like create a bitmap synced to a full backup without a transaction, or start a resumable backup process. Some combinations don't make sense, though: - NEVER policy combined with any non-BITMAP mode doesn't do anything, because the bitmap isn't used for input or output. It's harmless, but is almost certainly never what the user wanted. - sync=NONE is more questionable. It can't use on-success because this job never completes with success anyway, and the resulting artifact of 'always' is suspect: because we start with a full bitmap and only copy out segments that get written to, the final output bitmap will always be ... a fully set bitmap. Maybe there's contexts in which bitmaps make sense for sync=none, but not without more severe changes to the current job, and omitting it here doesn't prevent us from adding it later. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20190716000117.25219-11-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
Diffstat (limited to 'blockdev.c')
-rw-r--r--blockdev.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/blockdev.c b/blockdev.c
index f889da0b42..64d06d1f67 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3567,6 +3567,28 @@ static BlockJob *do_backup_common(BackupCommon *backup,
if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) {
return NULL;
}
+
+ /* This does not produce a useful bitmap artifact: */
+ if (backup->sync == MIRROR_SYNC_MODE_NONE) {
+ error_setg(errp, "sync mode '%s' does not produce meaningful bitmap"
+ " outputs", MirrorSyncMode_str(backup->sync));
+ return NULL;
+ }
+
+ /* If the bitmap isn't used for input or output, this is useless: */
+ if (backup->bitmap_mode == BITMAP_SYNC_MODE_NEVER &&
+ backup->sync != MIRROR_SYNC_MODE_BITMAP) {
+ error_setg(errp, "Bitmap sync mode '%s' has no meaningful effect"
+ " when combined with sync mode '%s'",
+ BitmapSyncMode_str(backup->bitmap_mode),
+ MirrorSyncMode_str(backup->sync));
+ return NULL;
+ }
+ }
+
+ if (!backup->has_bitmap && backup->has_bitmap_mode) {
+ error_setg(errp, "Cannot specify bitmap sync mode without a bitmap");
+ return NULL;
}
if (!backup->auto_finalize) {