From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32946) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dwqkZ-0001Zq-95 for qemu-devel@nongnu.org; Tue, 26 Sep 2017 10:22:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dwqkY-0005Vn-DG for qemu-devel@nongnu.org; Tue, 26 Sep 2017 10:22:15 -0400 From: Kevin Wolf Date: Tue, 26 Sep 2017 16:21:21 +0200 Message-Id: <20170926142133.2498-13-kwolf@redhat.com> In-Reply-To: <20170926142133.2498-1-kwolf@redhat.com> References: <20170926142133.2498-1-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 12/24] qemu-io: Drop write permissions before read-only reopen 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 qemu-io provides a 'reopen' command that allows switching from writable to read-only access. We need to make sure that we don't try to keep write permissions to a BlockBackend that becomes read-only, otherwise things are going to fail. This requires a bdrv_drain() call because otherwise in-flight AIO write requests could issue new internal requests while the permission has already gone away, which would cause assertion failures. Draining the queue doesn't break AIO requests in any new way, bdrv_reopen() would drain it anyway only a few lines later. Signed-off-by: Kevin Wolf Reviewed-by: Fam Zheng --- qemu-io-cmds.c | 12 ++++++++++++ tests/qemu-iotests/187.out | 2 +- 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c index 2811a89099..3727fb43f3 100644 --- a/qemu-io-cmds.c +++ b/qemu-io-cmds.c @@ -2010,6 +2010,18 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv) return 0; } + if (!(flags & BDRV_O_RDWR)) { + uint64_t orig_perm, orig_shared_perm; + + bdrv_drain(bs); + + blk_get_perm(blk, &orig_perm, &orig_shared_perm); + blk_set_perm(blk, + orig_perm & ~(BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED), + orig_shared_perm, + &error_abort); + } + qopts = qemu_opts_find(&reopen_opts, NULL); opts = qopts ? qemu_opts_to_qdict(qopts, NULL) : NULL; qemu_opts_reset(&reopen_opts); diff --git a/tests/qemu-iotests/187.out b/tests/qemu-iotests/187.out index 68fb944cd5..30b987f71f 100644 --- a/tests/qemu-iotests/187.out +++ b/tests/qemu-iotests/187.out @@ -12,7 +12,7 @@ Start from read-write wrote 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) -write failed: Operation not permitted +Block node is read-only wrote 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) *** done -- 2.13.5