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authorStefan Hajnoczi <stefanha@redhat.com>2014-10-21 12:03:58 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2014-11-03 11:41:49 +0000
commit5a7e7a0bad17c96e03f55ed7019e2d7545e21a96 (patch)
treed84566a65af84c20617ae6d288c3e876bfe3b6a2 /blockdev.c
parentf3e69beb942103ccd5248273e4d95e76b64ab64c (diff)
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block: let mirror blockjob run in BDS AioContext
The mirror block job must run in the BlockDriverState AioContext so that it works with dataplane. Acquire the AioContext in blockdev.c so starting the block job is safe. Note that to_replace is treated separately from other BlockDriverStates in that it does not need to be in the same AioContext. Explicitly acquire/release to_replace's AioContext when accessing it. The completion code in block/mirror.c must perform BDS graph manipulation and bdrv_reopen() from the main loop. Use block_job_defer_to_main_loop() to achieve that. The bdrv_drain_all() call is not allowed outside the main loop since it could lead to lock ordering problems. Use bdrv_drain(bs) instead because we have acquired the AioContext so nothing else can sneak in I/O. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 1413889440-32577-10-git-send-email-stefanha@redhat.com
Diffstat (limited to 'blockdev.c')
-rw-r--r--blockdev.c38
1 files changed, 27 insertions, 11 deletions
diff --git a/blockdev.c b/blockdev.c
index 6e43d2e..1376322 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2245,6 +2245,7 @@ void qmp_drive_mirror(const char *device, const char *target,
{
BlockDriverState *bs;
BlockDriverState *source, *target_bs;
+ AioContext *aio_context;
BlockDriver *drv = NULL;
Error *local_err = NULL;
QDict *options = NULL;
@@ -2287,9 +2288,12 @@ void qmp_drive_mirror(const char *device, const char *target,
return;
}
+ aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(aio_context);
+
if (!bdrv_is_inserted(bs)) {
error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
- return;
+ goto out;
}
if (!has_format) {
@@ -2299,12 +2303,12 @@ void qmp_drive_mirror(const char *device, const char *target,
drv = bdrv_find_format(format);
if (!drv) {
error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
- return;
+ goto out;
}
}
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR, errp)) {
- return;
+ goto out;
}
flags = bs->open_flags | BDRV_O_RDWR;
@@ -2319,29 +2323,36 @@ void qmp_drive_mirror(const char *device, const char *target,
size = bdrv_getlength(bs);
if (size < 0) {
error_setg_errno(errp, -size, "bdrv_getlength failed");
- return;
+ goto out;
}
if (has_replaces) {
BlockDriverState *to_replace_bs;
+ AioContext *replace_aio_context;
+ int64_t replace_size;
if (!has_node_name) {
error_setg(errp, "a node-name must be provided when replacing a"
" named node of the graph");
- return;
+ goto out;
}
to_replace_bs = check_to_replace_node(replaces, &local_err);
if (!to_replace_bs) {
error_propagate(errp, local_err);
- return;
+ goto out;
}
- if (size != bdrv_getlength(to_replace_bs)) {
+ replace_aio_context = bdrv_get_aio_context(to_replace_bs);
+ aio_context_acquire(replace_aio_context);
+ replace_size = bdrv_getlength(to_replace_bs);
+ aio_context_release(replace_aio_context);
+
+ if (size != replace_size) {
error_setg(errp, "cannot replace image with a mirror image of "
"different size");
- return;
+ goto out;
}
}
@@ -2370,7 +2381,7 @@ void qmp_drive_mirror(const char *device, const char *target,
if (local_err) {
error_propagate(errp, local_err);
- return;
+ goto out;
}
if (has_node_name) {
@@ -2386,9 +2397,11 @@ void qmp_drive_mirror(const char *device, const char *target,
flags | BDRV_O_NO_BACKING, drv, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
- return;
+ goto out;
}
+ bdrv_set_aio_context(target_bs, aio_context);
+
/* pass the node name to replace to mirror start since it's loose coupling
* and will allow to check whether the node still exist at mirror completion
*/
@@ -2400,8 +2413,11 @@ void qmp_drive_mirror(const char *device, const char *target,
if (local_err != NULL) {
bdrv_unref(target_bs);
error_propagate(errp, local_err);
- return;
+ goto out;
}
+
+out:
+ aio_context_release(aio_context);
}
/* Get the block job for a given device name and acquire its AioContext */