From patchwork Mon Sep 24 14:26:39 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 186476 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id CF8FF2C0083 for ; Tue, 25 Sep 2012 01:53:36 +1000 (EST) Received: from localhost ([::1]:59359 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TG9dQ-0000Qf-Oo for incoming@patchwork.ozlabs.org; Mon, 24 Sep 2012 10:27:44 -0400 Received: from eggs.gnu.org ([208.118.235.92]:41544) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TG9cs-0007N3-GB for qemu-devel@nongnu.org; Mon, 24 Sep 2012 10:27:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TG9cm-00079C-Rr for qemu-devel@nongnu.org; Mon, 24 Sep 2012 10:27:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22260) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TG9cm-00078w-Ji for qemu-devel@nongnu.org; Mon, 24 Sep 2012 10:27:04 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q8OER2Nv010231 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 24 Sep 2012 10:27:03 -0400 Received: from dhcp-5-188.str.redhat.com (dhcp-5-175.str.redhat.com [10.32.5.175]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q8OEQnYZ004629; Mon, 24 Sep 2012 10:27:02 -0400 From: Kevin Wolf To: anthony@codemonkey.ws Date: Mon, 24 Sep 2012 16:26:39 +0200 Message-Id: <1348496808-8159-11-git-send-email-kwolf@redhat.com> In-Reply-To: <1348496808-8159-1-git-send-email-kwolf@redhat.com> References: <1348496808-8159-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH 10/19] block: raw-posix image file reopen X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Jeff Cody This is derived from the Supriya Kannery's reopen patches. This contains the raw-posix driver changes for the bdrv_reopen_* functions. All changes are staged into a temporary scratch buffer during the prepare() stage, and copied over to the live structure during commit(). Upon abort(), all changes are abandoned, and the live structures are unmodified. The _prepare() will create an extra fd - either by means of a dup, if possible, or opening a new fd if not (for instance, access control changes). Upon _commit(), the original fd is closed and the new fd is used. Upon _abort(), the duplicate/new fd is closed. Signed-off-by: Jeff Cody Signed-off-by: Kevin Wolf --- block/raw-posix.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 114 insertions(+), 0 deletions(-) diff --git a/block/raw-posix.c b/block/raw-posix.c index 0ffb3d0..28d439f 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -138,6 +138,14 @@ typedef struct BDRVRawState { #endif } BDRVRawState; +typedef struct BDRVRawReopenState { + int fd; + int open_flags; +#ifdef CONFIG_LINUX_AIO + int use_aio; +#endif +} BDRVRawReopenState; + static int fd_open(BlockDriverState *bs); static int64_t raw_getlength(BlockDriverState *bs); @@ -290,6 +298,109 @@ static int raw_open(BlockDriverState *bs, const char *filename, int flags) return raw_open_common(bs, filename, flags, 0); } +static int raw_reopen_prepare(BDRVReopenState *state, + BlockReopenQueue *queue, Error **errp) +{ + BDRVRawState *s; + BDRVRawReopenState *raw_s; + int ret = 0; + + assert(state != NULL); + assert(state->bs != NULL); + + s = state->bs->opaque; + + state->opaque = g_malloc0(sizeof(BDRVRawReopenState)); + raw_s = state->opaque; + +#ifdef CONFIG_LINUX_AIO + raw_s->use_aio = s->use_aio; + + /* we can use s->aio_ctx instead of a copy, because the use_aio flag is + * valid in the 'false' condition even if aio_ctx is set, and raw_set_aio() + * won't override aio_ctx if aio_ctx is non-NULL */ + if (raw_set_aio(&s->aio_ctx, &raw_s->use_aio, state->flags)) { + return -1; + } +#endif + + raw_parse_flags(state->flags, &raw_s->open_flags); + + raw_s->fd = -1; + + int fcntl_flags = O_APPEND | O_ASYNC | O_NONBLOCK; +#ifdef O_NOATIME + fcntl_flags |= O_NOATIME; +#endif + + if ((raw_s->open_flags & ~fcntl_flags) == (s->open_flags & ~fcntl_flags)) { + /* dup the original fd */ + /* TODO: use qemu fcntl wrapper */ +#ifdef F_DUPFD_CLOEXEC + raw_s->fd = fcntl(s->fd, F_DUPFD_CLOEXEC, 0); +#else + raw_s->fd = dup(s->fd); + if (raw_s->fd != -1) { + qemu_set_cloexec(raw_s->fd); + } +#endif + if (raw_s->fd >= 0) { + ret = fcntl_setfl(raw_s->fd, raw_s->open_flags); + if (ret) { + qemu_close(raw_s->fd); + raw_s->fd = -1; + } + } + } + + /* If we cannot use fcntl, or fcntl failed, fall back to qemu_open() */ + if (raw_s->fd == -1) { + assert(!(raw_s->open_flags & O_CREAT)); + raw_s->fd = qemu_open(state->bs->filename, raw_s->open_flags); + if (raw_s->fd == -1) { + ret = -1; + } + } + return ret; +} + + +static void raw_reopen_commit(BDRVReopenState *state) +{ + BDRVRawReopenState *raw_s = state->opaque; + BDRVRawState *s = state->bs->opaque; + + s->open_flags = raw_s->open_flags; + + qemu_close(s->fd); + s->fd = raw_s->fd; +#ifdef CONFIG_LINUX_AIO + s->use_aio = raw_s->use_aio; +#endif + + g_free(state->opaque); + state->opaque = NULL; +} + + +static void raw_reopen_abort(BDRVReopenState *state) +{ + BDRVRawReopenState *raw_s = state->opaque; + + /* nothing to do if NULL, we didn't get far enough */ + if (raw_s == NULL) { + return; + } + + if (raw_s->fd >= 0) { + qemu_close(raw_s->fd); + raw_s->fd = -1; + } + g_free(state->opaque); + state->opaque = NULL; +} + + /* XXX: use host sector size if necessary with: #ifdef DIOCGSECTORSIZE { @@ -740,6 +851,9 @@ static BlockDriver bdrv_file = { .instance_size = sizeof(BDRVRawState), .bdrv_probe = NULL, /* no probe for protocols */ .bdrv_file_open = raw_open, + .bdrv_reopen_prepare = raw_reopen_prepare, + .bdrv_reopen_commit = raw_reopen_commit, + .bdrv_reopen_abort = raw_reopen_abort, .bdrv_close = raw_close, .bdrv_create = raw_create, .bdrv_co_discard = raw_co_discard,