[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v2 1/6] qemu-io: Drop write permissions before read-
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH v2 1/6] qemu-io: Drop write permissions before read-only reopen |
Date: |
Fri, 22 Sep 2017 14:55:59 +0200 |
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 <address@hidden>
---
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
- [Qemu-devel] [PATCH 0/6] block: Fix permissions after ro/rw reopen, Kevin Wolf, 2017/09/15
- [Qemu-devel] [PATCH 1/6] qemu-io: Reset qemuio_blk permissions before each command, Kevin Wolf, 2017/09/15
- [Qemu-devel] [PATCH 3/6] block: Add reopen queue to bdrv_check_perm(), Kevin Wolf, 2017/09/15
- [Qemu-devel] [PATCH 4/6] block: Base permissions on rw state after reopen, Kevin Wolf, 2017/09/15
- [Qemu-devel] [PATCH 2/6] block: Add reopen_queue to bdrv_child_perm(), Kevin Wolf, 2017/09/15
- [Qemu-devel] [PATCH 6/6] block: Fix permissions after bdrv_reopen(), Kevin Wolf, 2017/09/15