From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38980) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V04Hp-0005BC-Da for qemu-devel@nongnu.org; Fri, 19 Jul 2013 02:35:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V04Hm-0000qo-B6 for qemu-devel@nongnu.org; Fri, 19 Jul 2013 02:35:29 -0400 Received: from mx.ipv6.kamp.de ([2a02:248:0:51::16]:39191 helo=mx01.kamp.de) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1V04Hl-0000qa-WE for qemu-devel@nongnu.org; Fri, 19 Jul 2013 02:35:26 -0400 Message-ID: <51E8DE2C.9@kamp.de> Date: Fri, 19 Jul 2013 08:35:24 +0200 From: Peter Lieven MIME-Version: 1.0 References: <1373992168-26043-1-git-send-email-pbonzini@redhat.com> <1373992168-26043-11-git-send-email-pbonzini@redhat.com> In-Reply-To: <1373992168-26043-11-git-send-email-pbonzini@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v2 10/17] block: define get_block_status return value List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: famz@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com On 16.07.2013 18:29, Paolo Bonzini wrote: > Define the return value of get_block_status. Bits 0, 1, 2 and 9-62 > are valid; bit 63 (the sign bit) is reserved for errors. Bits 3-7 > are left for future extensions. > > The return code is compatible with the old is_allocated API: returning > just 0 or 1 (aka BDRV_BLOCK_DATA) will not cause any behavioral change > in clients of is_allocated. We will return more precise information > in the next patches. > > Signed-off-by: Paolo Bonzini > --- > v1->v2: improved comment > > block.c | 7 +++++-- > include/block/block.h | 26 ++++++++++++++++++++++++++ > 2 files changed, 31 insertions(+), 2 deletions(-) > > diff --git a/block.c b/block.c > index 6e7a8a3..7ff0716 100644 > --- a/block.c > +++ b/block.c > @@ -2990,7 +2990,7 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, > > if (!bs->drv->bdrv_co_get_block_status) { > *pnum = nb_sectors; > - return 1; > + return BDRV_BLOCK_DATA; > } > > return bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum); > @@ -3040,7 +3040,10 @@ int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, > int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, > int nb_sectors, int *pnum) > { > - return bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); > + int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); just stumbled about a question i have: isn't here a if (ret < 0) { *pnum = 0; return 0; } missing? I was told that this is the expected return behaviour in the error case of the old API. Peter > + return > + (ret & BDRV_BLOCK_DATA) || > + ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs)); > } > > /* > diff --git a/include/block/block.h b/include/block/block.h > index fbc0822..83c7112 100644 > --- a/include/block/block.h > +++ b/include/block/block.h > @@ -81,6 +81,32 @@ typedef struct BlockDevOps { > #define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS) > #define BDRV_SECTOR_MASK ~(BDRV_SECTOR_SIZE - 1) > > +/* BDRV_BLOCK_DATA: data is read from bs->file or another file > + * BDRV_BLOCK_ZERO: sectors read as zero > + * BDRV_BLOCK_OFFSET_VALID: sector stored in bs->file as raw data > + * > + * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 represent the offset in > + * bs->file where sector data can be read from as raw data. > + * > + * DATA == 0 && ZERO == 0 means that data is read from backing_hd if present. > + * > + * DATA ZERO OFFSET_VALID > + * t t t sectors read as zero, bs->file is zero at offset > + * t f t sectors read as valid from bs->file at offset > + * f t t sectors preallocated, read as zero, bs->file not > + * necessarily zero at offset > + * f f t sectors preallocated but read from backing_hd, > + * bs->file contains garbage at offset > + * t t f sectors preallocated, read as zero, unknown offset > + * t f f sectors read from unknown file or offset > + * f t f not allocated or unknown offset, read as zero > + * f f f not allocated or unknown offset, read from backing_hd > + */ > +#define BDRV_BLOCK_DATA 1 > +#define BDRV_BLOCK_ZERO 2 > +#define BDRV_BLOCK_OFFSET_VALID 4 > +#define BDRV_BLOCK_OFFSET_MASK BDRV_SECTOR_MASK > + > typedef enum { > BDRV_ACTION_REPORT, BDRV_ACTION_IGNORE, BDRV_ACTION_STOP > } BlockErrorAction; -- Mit freundlichen Grüßen Peter Lieven ........................................................... KAMP Netzwerkdienste GmbH Vestische Str. 89-91 | 46117 Oberhausen Tel: +49 (0) 208.89 402-50 | Fax: +49 (0) 208.89 402-40 pl@kamp.de | http://www.kamp.de Geschäftsführer: Heiner Lante | Michael Lante Amtsgericht Duisburg | HRB Nr. 12154 USt-Id-Nr.: DE 120607556 ...........................................................