From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36355) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XW5fL-00088M-MM for qemu-devel@nongnu.org; Mon, 22 Sep 2014 11:36:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XW5fF-00006i-CW for qemu-devel@nongnu.org; Mon, 22 Sep 2014 11:36:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13015) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XW5fF-0008W7-3U for qemu-devel@nongnu.org; Mon, 22 Sep 2014 11:36:33 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s8MFaRY7021512 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Mon, 22 Sep 2014 11:36:27 -0400 From: Max Reitz Date: Mon, 22 Sep 2014 17:36:18 +0200 Message-Id: <1411400179-10605-2-git-send-email-mreitz@redhat.com> In-Reply-To: <1411400179-10605-1-git-send-email-mreitz@redhat.com> References: <1411400179-10605-1-git-send-email-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH v2 1/2] raw-posix: Fix raw_co_get_block_status() after EOF List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Paolo Bonzini , Stefan Hajnoczi , Max Reitz As its comment states, raw_co_get_block_status() should unconditionally return 0 and set *pnum to 0 for after EOF. An assertion after lseek(..., SEEK_HOLE) tried to catch this case by asserting that errno != -ENXIO (which would indicate a position after the EOF); but it should be errno != ENXIO instead. Fix this, too. Additionally, nb_sectors should be clamped against the image end. This was probably not an issue if FIEMAP or SEEK_HOLE/SEEK_DATA worked, but the fallback did not take this case into account. Reported-by: Kevin Wolf Signed-off-by: Max Reitz --- block/raw-posix.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/block/raw-posix.c b/block/raw-posix.c index a253697..dd57992 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -1509,9 +1509,9 @@ static int64_t try_seek_hole(BlockDriverState *bs, off_t start, off_t *data, *hole = lseek(s->fd, start, SEEK_HOLE); if (*hole == -1) { - /* -ENXIO indicates that sector_num was past the end of the file. + /* ENXIO indicates that sector_num was past the end of the file. * There is a virtual hole there. */ - assert(errno != -ENXIO); + assert(errno != ENXIO); return -errno; } @@ -1552,6 +1552,7 @@ static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs, int nb_sectors, int *pnum) { off_t start, data = 0, hole = 0; + int64_t total_size; int64_t ret; ret = fd_open(bs); @@ -1560,6 +1561,13 @@ static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs, } start = sector_num * BDRV_SECTOR_SIZE; + total_size = bdrv_getlength(bs); + if (start >= total_size) { + *pnum = 0; + return 0; + } else if (start + nb_sectors * BDRV_SECTOR_SIZE > total_size) { + nb_sectors = (total_size - start) / BDRV_SECTOR_SIZE; + } ret = try_fiemap(bs, start, &data, &hole, nb_sectors, pnum); if (ret < 0) { -- 2.1.0