From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52154) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gJhx2-0003Gm-8G for qemu-devel@nongnu.org; Mon, 05 Nov 2018 11:42:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gJhwt-0005HD-2B for qemu-devel@nongnu.org; Mon, 05 Nov 2018 11:42:04 -0500 From: Kevin Wolf Date: Mon, 5 Nov 2018 17:37:32 +0100 Message-Id: <20181105163744.25139-25-kwolf@redhat.com> In-Reply-To: <20181105163744.25139-1-kwolf@redhat.com> References: <20181105163744.25139-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 24/36] file-posix: Support auto-read-only option List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org If read-only=3Doff, but auto-read-only=3Don is given, open the file read-write if we have the permissions, but instead of erroring out for read-only files, just degrade to read-only. Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake --- block/file-posix.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 2da3a76355..0c1b81ce4b 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -527,9 +527,22 @@ static int raw_open_common(BlockDriverState *bs, QDi= ct *options, =20 s->fd =3D -1; fd =3D qemu_open(filename, s->open_flags, 0644); - if (fd < 0) { - ret =3D -errno; - error_setg_errno(errp, errno, "Could not open '%s'", filename); + ret =3D fd < 0 ? -errno : 0; + + if (ret =3D=3D -EACCES || ret =3D=3D -EROFS) { + /* Try to degrade to read-only, but if it doesn't work, still us= e the + * normal error message. */ + if (bdrv_apply_auto_read_only(bs, NULL, NULL) =3D=3D 0) { + bdrv_flags &=3D ~BDRV_O_RDWR; + raw_parse_flags(bdrv_flags, &s->open_flags); + assert(!(s->open_flags & O_CREAT)); + fd =3D qemu_open(filename, s->open_flags); + ret =3D fd < 0 ? -errno : 0; + } + } + + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not open '%s'", filename); if (ret =3D=3D -EROFS) { ret =3D -EACCES; } --=20 2.19.1