From 71555531cfd9d8d81f572120cc0eae211f52c7d4 Mon Sep 17 00:00:00 2001 From: Jeffrey Cody Date: Wed, 21 Mar 2012 21:54:59 +0100 Subject: [PATCH 32/55] block: implement bdrv_co_is_allocated() boundary cases RH-Author: Jeffrey Cody Message-id: Patchwork-id: 38882 O-Subject: [RHEL6.3 qemu-kvm PATCH v8 32/54] block: implement bdrv_co_is_allocated() boundary cases Bugzilla: 582475 RH-Acked-by: Paolo Bonzini RH-Acked-by: Marcelo Tosatti RH-Acked-by: Kevin Wolf From: Stefan Hajnoczi Cases beyond the end of the disk image are only implemented for block drivers that do not provide .bdrv_co_is_allocated(). It's worth making these cases generic so that block drivers that do implement .bdrv_co_is_allocated() also get them for free. Suggested-by: Mark Wu Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf (cherry picked from commit bd9533e36ea3d6c964f65b8e407bad00dab59e5d) Signed-off-by: Stefan Hajnoczi Signed-off-by: Anthony Liguori Signed-off-by: Jeff Cody --- block.c | 26 ++++++++++++++++++-------- 1 files changed, 18 insertions(+), 8 deletions(-) Signed-off-by: Michal Novotny --- block.c | 26 ++++++++++++++++++-------- 1 files changed, 18 insertions(+), 8 deletions(-) diff --git a/block.c b/block.c index de69a5d..7ab68e3 100644 --- a/block.c +++ b/block.c @@ -1986,23 +1986,33 @@ typedef struct BdrvCoIsAllocatedData { * not implementing the functionality are assumed to not support backing files, * hence all their sectors are reported as allocated. * + * If 'sector_num' is beyond the end of the disk image the return value is 0 + * and 'pnum' is set to 0. + * * 'pnum' is set to the number of sectors (including and immediately following * the specified sector) that are known to be in the same * allocated/unallocated state. * - * 'nb_sectors' is the max value 'pnum' should be set to. + * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes + * beyond the end of the disk image it will be clamped. */ int coroutine_fn bdrv_co_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum) { + int64_t n; + + if (sector_num >= bs->total_sectors) { + *pnum = 0; + return 0; + } + + n = bs->total_sectors - sector_num; + if (n < nb_sectors) { + nb_sectors = n; + } + if (!bs->drv->bdrv_co_is_allocated) { - int64_t n; - if (sector_num >= bs->total_sectors) { - *pnum = 0; - return 0; - } - n = bs->total_sectors - sector_num; - *pnum = (n < nb_sectors) ? (n) : (nb_sectors); + *pnum = nb_sectors; return 1; } -- 1.7.7.6