From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=60161 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PgFPu-0006w1-7u for qemu-devel@nongnu.org; Fri, 21 Jan 2011 06:44:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PgFPs-0006Xz-TJ for qemu-devel@nongnu.org; Fri, 21 Jan 2011 06:44:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:1324) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PgFPs-0006Xl-Js for qemu-devel@nongnu.org; Fri, 21 Jan 2011 06:44:32 -0500 Message-ID: <4D3971F7.60704@redhat.com> Date: Fri, 21 Jan 2011 12:45:59 +0100 From: Kevin Wolf MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH] Fix block migration when the device size is not a multiple of 1 MB References: <1295449188-17877-1-git-send-email-Pierre.Riteau@irisa.fr> <4D394F0A.9020608@redhat.com> <21D45D98-E550-4DAB-9252-44B471595DC5@irisa.fr> In-Reply-To: <21D45D98-E550-4DAB-9252-44B471595DC5@irisa.fr> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Pierre Riteau Cc: qemu-devel@nongnu.org, tamura.yoshiaki@lab.ntt.co.jp Am 21.01.2011 12:38, schrieb Pierre Riteau: > On 21 janv. 2011, at 10:16, Kevin Wolf wrote: > >> Am 19.01.2011 15:59, schrieb Pierre Riteau: >>> b02bea3a85cc939f09aa674a3f1e4f36d418c007 added a check on the return >>> value of bdrv_write and aborts migration when it fails. However, if the >>> size of the block device to migrate is not a multiple of BLOCK_SIZE >>> (currently 1 MB), the last bdrv_write will fail with -EIO. >>> >>> Fixed by calling bdrv_write with the correct size of the last block. >>> --- >>> block-migration.c | 16 +++++++++++++++- >>> 1 files changed, 15 insertions(+), 1 deletions(-) >>> >>> diff --git a/block-migration.c b/block-migration.c >>> index 1475325..eeb9c62 100644 >>> --- a/block-migration.c >>> +++ b/block-migration.c >>> @@ -635,6 +635,8 @@ static int block_load(QEMUFile *f, void *opaque, int version_id) >>> int64_t addr; >>> BlockDriverState *bs; >>> uint8_t *buf; >>> + int64_t total_sectors; >>> + int nr_sectors; >>> >>> do { >>> addr = qemu_get_be64(f); >>> @@ -656,10 +658,22 @@ static int block_load(QEMUFile *f, void *opaque, int version_id) >>> return -EINVAL; >>> } >>> >>> + total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; >>> + if (total_sectors <= 0) { >>> + fprintf(stderr, "Error getting length of block device %s\n", device_name); >>> + return -EINVAL; >>> + } >> >> Can you resend the patch with error_report(), as Yoshi mentioned? >> >> Also, I would move the total_sectors calculation outside the loop - >> though I have no idea how many iterations it typically has, so it might >> not improve things a lot. > > Actually, it is not possible to move the total_sectors calculation outside the loop, since the loop can receive blocks from any device (this is why each block is prefixed by the device name). > I'm sending a new patch with a small optimization to avoid recalculating total_sectors when the device doesn't change in the next iteration. Right, I should have read a bit more context... I won't insist on an optimization in this case, but if you like to do it, go ahead. Kevin