Received: from eggs.gnu.org ([2001:4830:134:3::10]:54488) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Upjsn-0004lu-V0 for qemu-devel@nongnu.org; Thu, 20 Jun 2013 14:47:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Upjsd-0000Xk-3m for qemu-devel@nongnu.org; Thu, 20 Jun 2013 14:46:57 -0400 Received: from ssl.dlhnet.de ([91.198.192.8]:44053 helo=ssl.dlh.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Upjsc-0000Wz-Sk for qemu-devel@nongnu.org; Thu, 20 Jun 2013 14:46:46 -0400 From: Peter Lieven Date: Thu, 20 Jun 2013 20:08:46 +0200 Message-Id: <1371751726-16196-3-git-send-email-pl@kamp.de> In-Reply-To: <1371751726-16196-1-git-send-email-pl@kamp.de> References: <1371751726-16196-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCH 2/2] iscsi: add intelligent has_zero_init check List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , pbonzini@redhat.com, Peter Lieven , ronniesahlberg@gmail.com, Stefan Hajnoczi iscsi targets are not created by bdrv_create and thus we cannot blindly assume that a target is empty. to avoid writing and allocating blocks of zeroes we now check if all blocks of an existing target are unallocated and return 1 for bdrv_has_zero_init if the target is completely unalloacted and unallocated blocks read as zeroes. Signed-off-by: Peter Lieven --- block/iscsi.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/block/iscsi.c b/block/iscsi.c index e6b966d..fe41d9a 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -50,6 +50,7 @@ typedef struct IscsiLun { int events; QEMUTimer *nop_timer; uint8_t lbpme; + uint8_t lbprz; } IscsiLun; typedef struct IscsiAIOCB { @@ -1004,6 +1005,7 @@ static int iscsi_readcapacity_sync(IscsiLun *iscsilun) iscsilun->block_size = rc16->block_length; iscsilun->num_blocks = rc16->returned_lba + 1; iscsilun->lbpme = rc16->lbpme; + iscsilun->lbprz = rc16->lbprz; } } break; @@ -1249,7 +1251,28 @@ static int iscsi_truncate(BlockDriverState *bs, int64_t offset) static int iscsi_has_zero_init(BlockDriverState *bs) { - return 0; + IscsiLun *iscsilun = bs->opaque; + uint64_t lba; + int n, ret, nb_sectors; + + if (iscsilun->lbprz == 0) { + return 0; + } + + for (lba = 0; lba < iscsilun->num_blocks; lba += 1 << 26) { + nb_sectors = 1 << 26; + if (lba + nb_sectors > iscsilun->num_blocks) { + nb_sectors = iscsilun->num_blocks - lba; + } + nb_sectors *= (iscsilun->block_size / BDRV_SECTOR_SIZE); + n = 0; + ret = iscsi_co_is_allocated(bs, lba, nb_sectors, &n); + if (ret || n != nb_sectors) { + return 0; + } + } + + return 1; } static int iscsi_create(const char *filename, QEMUOptionParameter *options) -- 1.7.9.5