From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52240) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSUXK-0003Fs-4s for qemu-devel@nongnu.org; Mon, 11 Jun 2018 17:39:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fSUXJ-0000hu-2s for qemu-devel@nongnu.org; Mon, 11 Jun 2018 17:39:38 -0400 From: Eric Blake Date: Mon, 11 Jun 2018 16:39:26 -0500 Message-Id: <20180611213927.141894-2-eblake@redhat.com> In-Reply-To: <20180611213927.141894-1-eblake@redhat.com> References: <20180611213927.141894-1-eblake@redhat.com> Subject: [Qemu-devel] [PATCH 1/2] qemu-img: Fix assert when mapping unaligned raw file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, qemu-block@nongnu.org, qemu-stable@nongnu.org, Max Reitz Commit a290f085 exposed a latent bug in qemu-img map introduced during the conversion of block status to be byte-based. Earlier in commit 5e344dd8, the internal interface get_block_status() switched to take byte-based parameters, but still called a sector-based block layer function; as such, rounding was added in the lone caller to obey the contract. However, commit 237d78f8 changed get_block_status() to truly be byte-based, at which point rounding to sector boundaries can result in calling bdrv_block_status() with 'bytes == 0' (a coding error) when the boundary between data and a hole falls mid-sector (true for the past-EOF implicit hole present in POSIX files). Fix things by removing the rounding that is now no longer necessary. See also https://bugzilla.redhat.com/1589738 Fixes: 237d78f8 Reported-by: Dan Kenigsberg Reported-by: Nir Soffer Reported-by: Maor Lipchuk CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake --- qemu-img.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/qemu-img.c b/qemu-img.c index 1dcdd47254a..e1a506f7f67 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -2906,7 +2906,7 @@ static int img_map(int argc, char **argv) int64_t n; /* Probe up to 1 GiB at a time. */ - n = QEMU_ALIGN_DOWN(MIN(1 << 30, length - offset), BDRV_SECTOR_SIZE); + n = MIN(1 << 30, length - offset); ret = get_block_status(bs, offset, n, &next); if (ret < 0) { -- 2.14.4