From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41829) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZvzrR-0001Bp-7g for qemu-devel@nongnu.org; Mon, 09 Nov 2015 22:44:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZvzrQ-0001Qd-6f for qemu-devel@nongnu.org; Mon, 09 Nov 2015 22:44:45 -0500 From: Max Reitz Date: Tue, 10 Nov 2015 04:44:18 +0100 Message-Id: <1447127063-4662-4-git-send-email-mreitz@redhat.com> In-Reply-To: <1447127063-4662-1-git-send-email-mreitz@redhat.com> References: <1447127063-4662-1-git-send-email-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH 3/8] block: Let bdrv_open_inherit() return the snapshot List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: Kevin Wolf , qemu-devel@nongnu.org, Max Reitz 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 --- 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