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[Qemu-devel] [PATCH v12 09/14] qemu-img: Empty image after commit
From: |
Max Reitz |
Subject: |
[Qemu-devel] [PATCH v12 09/14] qemu-img: Empty image after commit |
Date: |
Tue, 26 Aug 2014 23:36:22 +0200 |
After the top image has been committed, it should be emptied unless
specified otherwise.
Signed-off-by: Max Reitz <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
qemu-img-cmds.hx | 4 ++--
qemu-img.c | 34 +++++++++++++++++++++++++++++++---
qemu-img.texi | 6 +++++-
3 files changed, 38 insertions(+), 6 deletions(-)
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 55aec6b..e2ceadf 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -22,9 +22,9 @@ STEXI
ETEXI
DEF("commit", img_commit,
- "commit [-q] [-f fmt] [-t cache] filename")
+ "commit [-q] [-f fmt] [-t cache] [-d] filename")
STEXI
address@hidden commit [-q] [-f @var{fmt}] [-t @var{cache}] @var{filename}
address@hidden commit [-q] [-f @var{fmt}] [-t @var{cache}] [-d] @var{filename}
ETEXI
DEF("compare", img_compare,
diff --git a/qemu-img.c b/qemu-img.c
index 006557b..cd9c17d 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -770,14 +770,14 @@ static int img_commit(int argc, char **argv)
int c, ret, flags;
const char *filename, *fmt, *cache;
BlockDriverState *bs, *base_bs;
- bool quiet = false;
+ bool quiet = false, drop = false;
Error *local_err = NULL;
CommonBlockJobCBInfo cbi;
fmt = NULL;
cache = BDRV_DEFAULT_CACHE;
for(;;) {
- c = getopt(argc, argv, "f:ht:q");
+ c = getopt(argc, argv, "f:ht:dq");
if (c == -1) {
break;
}
@@ -792,6 +792,9 @@ static int img_commit(int argc, char **argv)
case 't':
cache = optarg;
break;
+ case 'd':
+ drop = true;
+ break;
case 'q':
quiet = true;
break;
@@ -802,7 +805,7 @@ static int img_commit(int argc, char **argv)
}
filename = argv[optind++];
- flags = BDRV_O_RDWR;
+ flags = BDRV_O_RDWR | BDRV_O_UNMAP;
ret = bdrv_parse_cache_flags(cache, &flags);
if (ret < 0) {
error_report("Invalid cache option: %s", cache);
@@ -834,7 +837,32 @@ static int img_commit(int argc, char **argv)
goto done;
}
+ /* The block job will swap base_bs and bs (which is not what we really want
+ * here, but okay) and unref base_bs (after the swap, i.e., the old top
+ * image). In order to still be able to empty that top image afterwards,
+ * increment the reference counter here preemptively. */
+ if (!drop) {
+ bdrv_ref(base_bs);
+ }
+
run_block_job(bs->job, &local_err);
+ if (local_err) {
+ goto unref_backing;
+ }
+
+ if (!drop && base_bs->drv->bdrv_make_empty) {
+ ret = base_bs->drv->bdrv_make_empty(base_bs);
+ if (ret) {
+ error_setg_errno(&local_err, -ret, "Could not empty %s",
+ filename);
+ goto unref_backing;
+ }
+ }
+
+unref_backing:
+ if (!drop) {
+ bdrv_unref(base_bs);
+ }
done:
bdrv_unref(bs);
diff --git a/qemu-img.texi b/qemu-img.texi
index cb68948..3574145 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -166,7 +166,7 @@ this case. @var{backing_file} will never be modified unless
you use the
The size can also be specified using the @var{size} option with @code{-o},
it doesn't need to be specified separately in this case.
address@hidden commit [-f @var{fmt}] [-t @var{cache}] @var{filename}
address@hidden commit [-f @var{fmt}] [-t @var{cache}] [-d] @var{filename}
Commit the changes recorded in @var{filename} in its base image or backing
file.
If the backing file is smaller than the snapshot, then the backing file will be
@@ -175,6 +175,10 @@ the backing file, the backing file will not be truncated.
If you want the
backing file to match the size of the smaller snapshot, you can safely truncate
it yourself once the commit operation successfully completes.
+The image @var{filename} is emptied after the operation has succeeded. If you
do
+not need @var{filename} afterwards and intend to drop it, you may skip emptying
address@hidden by specifying the @code{-d} flag.
+
@item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s]
[-q] @var{filename1} @var{filename2}
Check if two images have the same content. You can compare images with
--
2.1.0
- [Qemu-devel] [PATCH v12 00/14] qemu-img: Implement commit like QMP, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 01/14] qcow2: Allow "full" discard, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 02/14] qcow2: Implement bdrv_make_empty(), Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 03/14] qcow2: Optimize bdrv_make_empty(), Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 04/14] blockjob: Introduce block_job_complete_sync(), Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 05/14] blockjob: Add "ready" field, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 06/14] iotests: Omit length/offset test in 040 and 041, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 07/14] block/mirror: Improve progress report, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 08/14] qemu-img: Implement commit like QMP, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 09/14] qemu-img: Empty image after commit,
Max Reitz <=
- [Qemu-devel] [PATCH v12 10/14] qemu-img: Enable progress output for commit, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 11/14] qemu-img: Specify backing file for commit, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 12/14] iotests: Add _filter_qemu_img_map, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 13/14] iotests: Add test for backing-chain commits, Max Reitz, 2014/08/26
- [Qemu-devel] [PATCH v12 14/14] iotests: Add test for qcow2's bdrv_make_empty, Max Reitz, 2014/08/26