From nobody Wed Nov 5 06:38:42 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1499634615171867.4865556613545; Sun, 9 Jul 2017 14:10:15 -0700 (PDT) Received: from localhost ([::1]:37511 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dUJT3-0005YL-Tt for importer@patchew.org; Sun, 09 Jul 2017 17:10:13 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34162) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dUJQM-0003mY-FT for qemu-devel@nongnu.org; Sun, 09 Jul 2017 17:07:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dUJQJ-0006RX-BG for qemu-devel@nongnu.org; Sun, 09 Jul 2017 17:07:26 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:37505) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dUJQJ-0006R9-3h; Sun, 09 Jul 2017 17:07:23 -0400 Received: from mnementh.archaic.org.uk ([81.2.115.146]) by orth.archaic.org.uk with esmtp (Exim 4.84_2) (envelope-from ) id 1dUJQD-0000yM-VZ; Sun, 09 Jul 2017 22:07:17 +0100 Received: from pm215 by mnementh.archaic.org.uk with local (Exim 4.89) (envelope-from ) id 1dUJQD-0000Gg-UJ; Sun, 09 Jul 2017 22:07:17 +0100 From: Peter Maydell To: qemu-devel@nongnu.org Date: Sun, 9 Jul 2017 22:07:17 +0100 Message-Id: <20170709210717.984-1-peter.maydell@linaro.org> X-Mailer: git-send-email 2.11.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:8b0:1d0::2 Subject: [Qemu-devel] [PATCH] block/vpc.c: Handle write failures in get_image_offset() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Max Reitz , qemu-block@nongnu.org, patches@linaro.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Coverity (CID 1355236) points out that get_image_offset() doesn't check that it actually succeeded in writing the updated block bitmap to the file. Check the error return from bdrv_pwrite_sync() and propagate an error response back up to the function which calls get_image_offset() for a write so that it can return the error to its caller. get_sector_offset() is only used for reads, but we move it to the same API for consistency. Signed-off-by: Peter Maydell --- The new get_image_offset() API is pretty clunky, but I couldn't think of anything better -- we need to report one of 3 things: * offset number (0..INT64_MAX) * sector not allocated * arbitrary errno and they won't all fit into one return value. I opted for "minimal change compared to current code". --- block/vpc.c | 34 +++++++++++++++++++++++++--------- 1 file changed, 25 insertions(+), 9 deletions(-) diff --git a/block/vpc.c b/block/vpc.c index 4240ba9d1c..b93211df36 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -460,17 +460,23 @@ static int vpc_reopen_prepare(BDRVReopenState *state, /* * Returns the absolute byte offset of the given sector in the image file. * If the sector is not allocated, -1 is returned instead. + * If an error occurred trying to write an updated block bitmap back to + * the file, -2 is returned, and the error value is written to *err. + * This can only happen for a write operation. * * The parameter write must be 1 if the offset will be used for a write * operation (the block bitmaps is updated then), 0 otherwise. + * If write is true then err must not be NULL. */ static inline int64_t get_image_offset(BlockDriverState *bs, uint64_t offs= et, - bool write) + bool write, int *err) { BDRVVPCState *s =3D bs->opaque; uint64_t bitmap_offset, block_offset; uint32_t pagetable_index, offset_in_block; =20 + assert(!(write && err =3D=3D NULL)); + pagetable_index =3D offset / s->block_size; offset_in_block =3D offset % s->block_size; =20 @@ -487,19 +493,25 @@ static inline int64_t get_image_offset(BlockDriverSta= te *bs, uint64_t offset, correctness. */ if (write && (s->last_bitmap_offset !=3D bitmap_offset)) { uint8_t bitmap[s->bitmap_size]; + int r; =20 s->last_bitmap_offset =3D bitmap_offset; memset(bitmap, 0xff, s->bitmap_size); - bdrv_pwrite_sync(bs->file, bitmap_offset, bitmap, s->bitmap_size); + r =3D bdrv_pwrite_sync(bs->file, bitmap_offset, bitmap, s->bitmap_= size); + if (r < 0) { + *err =3D r; + return -2; + } } =20 return block_offset; } =20 static inline int64_t get_sector_offset(BlockDriverState *bs, - int64_t sector_num, bool write) + int64_t sector_num, bool write, + int *err) { - return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, write); + return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, write, err); } =20 /* @@ -567,7 +579,7 @@ static int64_t alloc_block(BlockDriverState* bs, int64_= t offset) if (ret < 0) goto fail; =20 - return get_image_offset(bs, offset, false); + return get_image_offset(bs, offset, false, NULL); =20 fail: s->free_data_block_offset -=3D (s->block_size + s->bitmap_size); @@ -607,7 +619,7 @@ vpc_co_preadv(BlockDriverState *bs, uint64_t offset, ui= nt64_t bytes, qemu_iovec_init(&local_qiov, qiov->niov); =20 while (bytes > 0) { - image_offset =3D get_image_offset(bs, offset, false); + image_offset =3D get_image_offset(bs, offset, false, NULL); n_bytes =3D MIN(bytes, s->block_size - (offset % s->block_size)); =20 if (image_offset =3D=3D -1) { @@ -656,7 +668,11 @@ vpc_co_pwritev(BlockDriverState *bs, uint64_t offset, = uint64_t bytes, qemu_iovec_init(&local_qiov, qiov->niov); =20 while (bytes > 0) { - image_offset =3D get_image_offset(bs, offset, true); + image_offset =3D get_image_offset(bs, offset, true, &ret); + if (image_offset =3D=3D -2) { + /* Failed to write block bitmap: can't proceed with write */ + goto fail; + } n_bytes =3D MIN(bytes, s->block_size - (offset % s->block_size)); =20 if (image_offset =3D=3D -1) { @@ -705,7 +721,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(Blo= ckDriverState *bs, (sector_num << BDRV_SECTOR_BITS); } =20 - offset =3D get_sector_offset(bs, sector_num, 0); + offset =3D get_sector_offset(bs, sector_num, false, NULL); start =3D offset; allocated =3D (offset !=3D -1); *pnum =3D 0; @@ -728,7 +744,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(Blo= ckDriverState *bs, if (nb_sectors =3D=3D 0) { break; } - offset =3D get_sector_offset(bs, sector_num, 0); + offset =3D get_sector_offset(bs, sector_num, false, NULL); } while (offset =3D=3D -1); =20 return 0; --=20 2.11.0