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[Qemu-devel] [PATCH 3/8] block: Let bdrv_open_inherit() return the snaps
From: |
Max Reitz |
Subject: |
[Qemu-devel] [PATCH 3/8] block: Let bdrv_open_inherit() return the snapshot |
Date: |
Tue, 10 Nov 2015 04:44:18 +0100 |
If bdrv_open_inherit() creates a snapshot BDS and *pbs is NULL, that
snapshot BDS should be returned instead of the BDS under it.
To this end, bdrv_append_temp_snapshot() now returns the snapshot BDS
instead of just appending it on top of the snapshotted BDS, and that
function is made static since bdrv_open_inherit() is its only user
anyway. Also, it calls bdrv_ref() before bdrv_append() (which
bdrv_open_inherit() has to undo if not returning the overlay).
Signed-off-by: Max Reitz <address@hidden>
---
block.c | 27 +++++++++++++++++++++++----
include/block/block.h | 1 -
2 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/block.c b/block.c
index aae1d69..c5ea5e7 100644
--- a/block.c
+++ b/block.c
@@ -1295,7 +1295,8 @@ done:
return c;
}
-int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp)
+static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
+ int flags, Error **errp)
{
/* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
char *tmp_filename = g_malloc0(PATH_MAX + 1);
@@ -1354,11 +1355,15 @@ int bdrv_append_temp_snapshot(BlockDriverState *bs, int
flags, Error **errp)
goto out;
}
+ bdrv_ref(bs_snapshot);
bdrv_append(bs_snapshot, bs);
+ g_free(tmp_filename);
+ return bs_snapshot;
+
out:
g_free(tmp_filename);
- return ret;
+ return NULL;
}
/*
@@ -1557,15 +1562,29 @@ static int bdrv_open_inherit(BlockDriverState **pbs,
const char *filename,
}
QDECREF(options);
- *pbs = bs;
/* For snapshot=on, create a temporary qcow2 overlay. bs points to the
* temporary snapshot afterwards. */
if (snapshot_flags) {
- ret = bdrv_append_temp_snapshot(bs, snapshot_flags, &local_err);
+ BlockDriverState *snapshot_bs;
+ snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
&local_err);
if (local_err) {
+ ret = -EINVAL;
goto close_and_fail;
}
+ if (!*pbs) {
+ /* The reference is now held by the overlay BDS */
+ bdrv_unref(bs);
+ bs = snapshot_bs;
+ } else {
+ /* It is still referenced in the same way that *pbs was referenced,
+ * however that may be */
+ bdrv_unref(snapshot_bs);
+ }
+ }
+
+ if (!*pbs) {
+ *pbs = bs;
}
return 0;
diff --git a/include/block/block.h b/include/block/block.h
index 1abfc70..37e49a1 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -210,7 +210,6 @@ BdrvChild *bdrv_open_child(const char *filename,
bool allow_none, Error **errp);
void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd);
int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp);
-int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp);
int bdrv_open(BlockDriverState **pbs, const char *filename,
const char *reference, QDict *options, int flags, Error **errp);
BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
--
2.6.2
- [Qemu-devel] [PATCH 0/8] blockdev: (Nearly) free clean-up work, Max Reitz, 2015/11/09
- [Qemu-devel] [PATCH 1/8] qapi: Drop QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, Max Reitz, 2015/11/09
- [Qemu-devel] [PATCH 2/8] block: Drop useless bdrv_new() calls, Max Reitz, 2015/11/09
- [Qemu-devel] [PATCH 3/8] block: Let bdrv_open_inherit() return the snapshot,
Max Reitz <=
- [Qemu-devel] [PATCH 5/8] block: Drop blk_new_with_bs(), Max Reitz, 2015/11/09
- [Qemu-devel] [PATCH 4/8] block: Drop BB name from bad option error, Max Reitz, 2015/11/09
- [Qemu-devel] [PATCH 6/8] block: Drop bdrv_new_root(), Max Reitz, 2015/11/09
- [Qemu-devel] [PATCH 8/8] block: Assert !bs->refcnt in bdrv_close(), Max Reitz, 2015/11/09
- [Qemu-devel] [PATCH 7/8] block: Make bdrv_open() return a BDS, Max Reitz, 2015/11/09