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[82.56.119.18]) by mx.google.com with ESMTPSA id pg6sm42904420qeb.5.2013.07.03.07.35.06 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Wed, 03 Jul 2013 07:35:08 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Wed, 3 Jul 2013 16:34:24 +0200 Message-Id: <1372862071-28225-11-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1372862071-28225-1-git-send-email-pbonzini@redhat.com> References: <1372862071-28225-1-git-send-email-pbonzini@redhat.com> X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2607:f8b0:400d:c02::22c Cc: kwolf@redhat.com, pl@kamp.de, stefanha@redhat.com Subject: [Qemu-devel] [PATCH 10/17] block: define get_block_status return value 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 Define the return value of get_block_status. Bits 0, 1, 2 and 8-62 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 --- block.c | 7 +++++-- include/block/block.h | 23 +++++++++++++++++++++++ 2 files changed, 28 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index aa1a5f7..8931cac 100644 --- a/block.c +++ b/block.c @@ -2976,7 +2976,7 @@ 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); @@ -3026,7 +3026,10 @@ 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); + 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 2b50b51..9e44bdd 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -81,6 +81,29 @@ 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: contents of sector available in bs->file at offset + * + * 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;