From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50414) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZL6TS-0000qj-UP for qemu-devel@nongnu.org; Fri, 31 Jul 2015 05:19:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZL6TQ-0006kO-2v for qemu-devel@nongnu.org; Fri, 31 Jul 2015 05:19:30 -0400 From: Wen Congyang Date: Fri, 31 Jul 2015 17:19:13 +0800 Message-ID: <1438334355-26914-5-git-send-email-wency@cn.fujitsu.com> In-Reply-To: <1438334355-26914-1-git-send-email-wency@cn.fujitsu.com> References: <1438334355-26914-1-git-send-email-wency@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH for-2.5 4/6] quorum: implement block driver interfaces add/delete a BDS's child List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu devel , Eric Blake , Markus Armbruster , Alberto Garcia , Stefan Hajnoczi Cc: Kevin Wolf , qemu block , Jiang Yunhong , Dong Eddie , "Dr. David Alan Gilbert" , Gonglei , Yang Hongyang , zhanghailiang Signed-off-by: Wen Congyang Signed-off-by: zhanghailiang Signed-off-by: Gonglei Cc: Alberto Garcia --- block/quorum.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 72 insertions(+), 2 deletions(-) diff --git a/block/quorum.c b/block/quorum.c index 4e66221..1c09265 100644 --- a/block/quorum.c +++ b/block/quorum.c @@ -66,6 +66,9 @@ typedef struct QuorumVotes { typedef struct BDRVQuorumState { BlockDriverState **bs; /* children BlockDriverStates */ int num_children; /* children count */ + int max_children; /* The maximum children count, we need to reallocate + * bs if num_children will larger than maximum. + */ int threshold; /* if less than threshold children reads gave the * same result a quorum error occurs. */ @@ -880,9 +883,9 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags, ret = -EINVAL; goto exit; } - if (s->num_children < 2) { + if (s->num_children < 1) { error_setg(&local_err, - "Number of provided children must be greater than 1"); + "Number of provided children must be 1 or more"); ret = -EINVAL; goto exit; } @@ -931,6 +934,7 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags, /* allocate the children BlockDriverState array */ s->bs = g_new0(BlockDriverState *, s->num_children); opened = g_new0(bool, s->num_children); + s->max_children = s->num_children; for (i = 0; i < s->num_children; i++) { char indexstr[32]; @@ -1001,6 +1005,69 @@ static void quorum_attach_aio_context(BlockDriverState *bs, } } +static void quorum_add_child(BlockDriverState *bs, QDict *options, Error **errp) +{ + BDRVQuorumState *s = bs->opaque; + int ret; + Error *local_err = NULL; + + bdrv_drain(bs); + + if (s->num_children == s->max_children) { + if (s->max_children >= INT_MAX) { + error_setg(errp, "Too many children"); + return; + } + + s->bs = g_renew(BlockDriverState *, s->bs, s->max_children + 1); + s->bs[s->num_children] = NULL; + s->max_children += 1; + } + + ret = bdrv_open_image(&s->bs[s->num_children], NULL, options, "child", bs, + &child_format, false, &local_err); + if (ret < 0) { + error_propagate(errp, local_err); + return; + } + s->num_children++; +} + +static void quorum_del_child(BlockDriverState *bs, BlockDriverState *child_bs, + Error **errp) +{ + BDRVQuorumState *s = bs->opaque; + int i; + + for (i = 0; i < s->num_children; i++) { + if (s->bs[i] == child_bs) { + break; + } + } + + if (i == s->num_children) { + error_setg(errp, "Invalid child"); + return; + } + + if (s->num_children <= s->threshold) { + error_setg(errp, "Cannot remove any more child"); + return; + } + + if (s->num_children == 1) { + error_setg(errp, "Cannot remove the last child"); + return; + } + + bdrv_drain(bs); + /* We can safe remove this child now */ + memmove(&s->bs[i], &s->bs[i+1], (s->num_children - i - 1) * sizeof(void *)); + s->num_children--; + s->bs[s->num_children] = NULL; + bdrv_unref(child_bs); +} + static void quorum_refresh_filename(BlockDriverState *bs) { BDRVQuorumState *s = bs->opaque; @@ -1055,6 +1122,9 @@ static BlockDriver bdrv_quorum = { .bdrv_detach_aio_context = quorum_detach_aio_context, .bdrv_attach_aio_context = quorum_attach_aio_context, + .bdrv_add_child = quorum_add_child, + .bdrv_del_child = quorum_del_child, + .is_filter = true, .bdrv_recurse_is_first_non_filter = quorum_recurse_is_first_non_filter, }; -- 2.4.3