From: Sergio Lopez <slp@redhat.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org,
Sergio Lopez <slp@redhat.com>,
mreitz@redhat.com
Subject: [Qemu-devel] [PATCH v2 2/2] blockdev: honor bdrv_try_set_aio_context() context requirements
Date: Fri, 13 Sep 2019 17:25:08 +0200 [thread overview]
Message-ID: <20190913152507.56197-3-slp@redhat.com> (raw)
In-Reply-To: <20190913152507.56197-1-slp@redhat.com>
bdrv_try_set_aio_context() requires that the old context is held, and
the new context is not held. Fix all the ocurrences where it's not
done this way.
Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Sergio Lopez <slp@redhat.com>
---
blockdev.c | 121 +++++++++++++++++++++++++++++++++--------------------
1 file changed, 75 insertions(+), 46 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 3927fdab80..2534fef389 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1536,6 +1536,7 @@ static void external_snapshot_prepare(BlkActionState *common,
DO_UPCAST(ExternalSnapshotState, common, common);
TransactionAction *action = common->action;
AioContext *aio_context;
+ AioContext *old_context;
int ret;
/* 'blockdev-snapshot' and 'blockdev-snapshot-sync' have similar
@@ -1575,30 +1576,30 @@ static void external_snapshot_prepare(BlkActionState *common,
aio_context = bdrv_get_aio_context(state->old_bs);
aio_context_acquire(aio_context);
-
/* Paired with .clean() */
bdrv_drained_begin(state->old_bs);
+ aio_context_release(aio_context);
if (!bdrv_is_inserted(state->old_bs)) {
error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
- goto out;
+ return;
}
if (bdrv_op_is_blocked(state->old_bs,
BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT, errp)) {
- goto out;
+ return;
}
if (!bdrv_is_read_only(state->old_bs)) {
if (bdrv_flush(state->old_bs)) {
error_setg(errp, QERR_IO_ERROR);
- goto out;
+ return;
}
}
if (!bdrv_is_first_non_filter(state->old_bs)) {
error_setg(errp, QERR_FEATURE_DISABLED, "snapshot");
- goto out;
+ return;
}
if (action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC) {
@@ -1610,13 +1611,13 @@ static void external_snapshot_prepare(BlkActionState *common,
if (node_name && !snapshot_node_name) {
error_setg(errp, "New overlay node name missing");
- goto out;
+ return;
}
if (snapshot_node_name &&
bdrv_lookup_bs(snapshot_node_name, snapshot_node_name, NULL)) {
error_setg(errp, "New overlay node name already in use");
- goto out;
+ return;
}
flags = state->old_bs->open_flags;
@@ -1629,7 +1630,7 @@ static void external_snapshot_prepare(BlkActionState *common,
int64_t size = bdrv_getlength(state->old_bs);
if (size < 0) {
error_setg_errno(errp, -size, "bdrv_getlength failed");
- goto out;
+ return;
}
bdrv_refresh_filename(state->old_bs);
bdrv_img_create(new_image_file, format,
@@ -1638,7 +1639,7 @@ static void external_snapshot_prepare(BlkActionState *common,
NULL, size, flags, false, &local_err);
if (local_err) {
error_propagate(errp, local_err);
- goto out;
+ return;
}
}
@@ -1653,34 +1654,41 @@ static void external_snapshot_prepare(BlkActionState *common,
errp);
/* We will manually add the backing_hd field to the bs later */
if (!state->new_bs) {
- goto out;
+ return;
}
if (bdrv_has_blk(state->new_bs)) {
error_setg(errp, "The overlay is already in use");
- goto out;
+ return;
}
if (bdrv_op_is_blocked(state->new_bs, BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
errp)) {
- goto out;
+ return;
}
if (state->new_bs->backing != NULL) {
error_setg(errp, "The overlay already has a backing image");
- goto out;
+ return;
}
if (!state->new_bs->drv->supports_backing) {
error_setg(errp, "The overlay does not support backing images");
- goto out;
+ return;
}
+ old_context = bdrv_get_aio_context(state->new_bs);
+ aio_context_acquire(old_context);
+
ret = bdrv_try_set_aio_context(state->new_bs, aio_context, errp);
if (ret < 0) {
- goto out;
+ aio_context_release(old_context);
+ return;
}
+ aio_context_release(old_context);
+ aio_context_acquire(aio_context);
+
/* This removes our old bs and adds the new bs. This is an operation that
* can fail, so we need to do it in .prepare; undoing it for abort is
* always possible. */
@@ -1688,11 +1696,10 @@ static void external_snapshot_prepare(BlkActionState *common,
bdrv_append(state->new_bs, state->old_bs, &local_err);
if (local_err) {
error_propagate(errp, local_err);
- goto out;
+ } else {
+ state->overlay_appended = true;
}
- state->overlay_appended = true;
-out:
aio_context_release(aio_context);
}
@@ -3490,13 +3497,11 @@ out:
static BlockJob *do_backup_common(BackupCommon *backup,
BlockDriverState *bs,
BlockDriverState *target_bs,
- AioContext *aio_context,
JobTxn *txn, Error **errp)
{
BlockJob *job = NULL;
BdrvDirtyBitmap *bmap = NULL;
int job_flags = JOB_DEFAULT;
- int ret;
if (!backup->has_speed) {
backup->speed = 0;
@@ -3520,11 +3525,6 @@ static BlockJob *do_backup_common(BackupCommon *backup,
backup->compress = false;
}
- ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
- if (ret < 0) {
- return NULL;
- }
-
if ((backup->sync == MIRROR_SYNC_MODE_BITMAP) ||
(backup->sync == MIRROR_SYNC_MODE_INCREMENTAL)) {
/* done before desugaring 'incremental' to print the right message */
@@ -3611,11 +3611,13 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
BlockDriverState *source = NULL;
BlockJob *job = NULL;
AioContext *aio_context;
+ AioContext *old_context;
QDict *options;
Error *local_err = NULL;
int flags;
int64_t size;
bool set_backing_hd = false;
+ int ret;
if (!backup->has_mode) {
backup->mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
@@ -3631,9 +3633,6 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
return NULL;
}
- aio_context = bdrv_get_aio_context(bs);
- aio_context_acquire(aio_context);
-
if (!backup->has_format) {
backup->format = backup->mode == NEW_IMAGE_MODE_EXISTING ?
NULL : (char*) bs->drv->format_name;
@@ -3641,7 +3640,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
/* Early check to avoid creating target */
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
- goto out;
+ return NULL;
}
flags = bs->open_flags | BDRV_O_RDWR;
@@ -3663,7 +3662,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
size = bdrv_getlength(bs);
if (size < 0) {
error_setg_errno(errp, -size, "bdrv_getlength failed");
- goto out;
+ return NULL;
}
if (backup->mode != NEW_IMAGE_MODE_EXISTING) {
@@ -3681,7 +3680,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
if (local_err) {
error_propagate(errp, local_err);
- goto out;
+ return NULL;
}
options = qdict_new();
@@ -3693,22 +3692,34 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
target_bs = bdrv_open(backup->target, NULL, options, flags, errp);
if (!target_bs) {
- goto out;
+ return NULL;
+ }
+
+ aio_context = bdrv_get_aio_context(bs);
+ old_context = bdrv_get_aio_context(target_bs);
+ aio_context_acquire(old_context);
+
+ ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
+ if (ret < 0) {
+ aio_context_release(old_context);
+ return NULL;
}
+ aio_context_release(old_context);
+ aio_context_acquire(aio_context);
+
if (set_backing_hd) {
bdrv_set_backing_hd(target_bs, source, &local_err);
if (local_err) {
- goto unref;
+ goto out;
}
}
job = do_backup_common(qapi_DriveBackup_base(backup),
- bs, target_bs, aio_context, txn, errp);
+ bs, target_bs, txn, errp);
-unref:
- bdrv_unref(target_bs);
out:
+ bdrv_unref(target_bs);
aio_context_release(aio_context);
return job;
}
@@ -3739,7 +3750,9 @@ BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
BlockDriverState *bs;
BlockDriverState *target_bs;
AioContext *aio_context;
+ AioContext *old_context;
BlockJob *job;
+ int ret;
bs = bdrv_lookup_bs(backup->device, backup->device, errp);
if (!bs) {
@@ -3752,10 +3765,20 @@ BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
}
aio_context = bdrv_get_aio_context(bs);
+ old_context = bdrv_get_aio_context(target_bs);
+ aio_context_acquire(old_context);
+
+ ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
+ if (ret < 0) {
+ aio_context_release(old_context);
+ return NULL;
+ }
+
+ aio_context_release(old_context);
aio_context_acquire(aio_context);
job = do_backup_common(qapi_BlockdevBackup_base(backup),
- bs, target_bs, aio_context, txn, errp);
+ bs, target_bs, txn, errp);
aio_context_release(aio_context);
return job;
@@ -3897,6 +3920,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
BlockDriverState *bs;
BlockDriverState *source, *target_bs;
AioContext *aio_context;
+ AioContext *old_context;
BlockMirrorBackingMode backing_mode;
Error *local_err = NULL;
QDict *options = NULL;
@@ -3916,9 +3940,6 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
return;
}
- aio_context = bdrv_get_aio_context(bs);
- aio_context_acquire(aio_context);
-
if (!arg->has_mode) {
arg->mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
}
@@ -3940,14 +3961,14 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
size = bdrv_getlength(bs);
if (size < 0) {
error_setg_errno(errp, -size, "bdrv_getlength failed");
- goto out;
+ return;
}
if (arg->has_replaces) {
if (!arg->has_node_name) {
error_setg(errp, "a node-name must be provided when replacing a"
" named node of the graph");
- goto out;
+ return;
}
}
@@ -3986,7 +4007,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
if (local_err) {
error_propagate(errp, local_err);
- goto out;
+ return;
}
options = qdict_new();
@@ -4002,19 +4023,27 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
*/
target_bs = bdrv_open(arg->target, NULL, options, flags, errp);
if (!target_bs) {
- goto out;
+ return;
}
zero_target = (arg->sync == MIRROR_SYNC_MODE_FULL &&
(arg->mode == NEW_IMAGE_MODE_EXISTING ||
!bdrv_has_zero_init(target_bs)));
+ aio_context = bdrv_get_aio_context(bs);
+ old_context = bdrv_get_aio_context(target_bs);
+ aio_context_acquire(old_context);
+
ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
if (ret < 0) {
bdrv_unref(target_bs);
- goto out;
+ aio_context_release(old_context);
+ return;
}
+ aio_context_release(old_context);
+ aio_context_acquire(aio_context);
+
blockdev_mirror_common(arg->has_job_id ? arg->job_id : NULL, bs, target_bs,
arg->has_replaces, arg->replaces, arg->sync,
backing_mode, zero_target,
@@ -4031,7 +4060,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
&local_err);
bdrv_unref(target_bs);
error_propagate(errp, local_err);
-out:
+
aio_context_release(aio_context);
}
--
2.21.0
prev parent reply other threads:[~2019-09-13 15:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-13 15:25 [Qemu-devel] [PATCH v2 0/2] blockdev: avoid acquiring AioContext lock twice at do_drive_backup() Sergio Lopez
2019-09-13 15:25 ` [Qemu-devel] [PATCH v2 1/2] blockdev: release the AioContext at drive_backup_prepare Sergio Lopez
2019-09-13 19:54 ` [Qemu-devel] [Qemu-block] " John Snow
2019-09-16 7:53 ` Kevin Wolf
2019-09-16 11:17 ` Sergio Lopez
2019-10-03 9:33 ` Sergio Lopez
2019-10-10 15:02 ` Kevin Wolf
2019-09-16 11:17 ` [Qemu-devel] " Sergio Lopez
2019-09-13 15:25 ` Sergio Lopez [this message]
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