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qcow2: Always execute preallocate() in a coroutine 

Some qcow2 functions (at least perform_cow()) expect s->lock to be
taken.  Therefore, if we want to make use of them, we should execute
preallocate() (as "preallocate_co") in a coroutine so that we can use
the qemu_co_mutex_* functions.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171009215533.12530-3-mreitz@redhat.com
Cc: qemu-stable@nongnu.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Max Reitz 2017-10-09 23:55:32 +02:00
parent e400ad1e1f
commit 572b07bea1
1 changed files with 34 additions and 7 deletions
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41
block/qcow2.c
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@ -2460,6 +2460,14 @@ static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt,
}
typedef struct PreallocCo {
BlockDriverState *bs;
uint64_t offset;
uint64_t new_length;
int ret;
} PreallocCo;
/**
* Preallocates metadata structures for data clusters between @offset (in the
* guest disk) and @new_length (which is thus generally the new guest disk
@ -2467,9 +2475,12 @@ static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt,
*
* Returns: 0 on success, -errno on failure.
*/
static int preallocate(BlockDriverState *bs,
uint64_t offset, uint64_t new_length)
static void coroutine_fn preallocate_co(void *opaque)
{
PreallocCo *params = opaque;
BlockDriverState *bs = params->bs;
uint64_t offset = params->offset;
uint64_t new_length = params->new_length;
BDRVQcow2State *s = bs->opaque;
uint64_t bytes;
uint64_t host_offset = 0;
@ -2477,9 +2488,7 @@ static int preallocate(BlockDriverState *bs,
int ret;
QCowL2Meta *meta;
if (qemu_in_coroutine()) {
qemu_co_mutex_lock(&s->lock);
}
qemu_co_mutex_lock(&s->lock);
assert(offset <= new_length);
bytes = new_length - offset;
@ -2533,10 +2542,28 @@ static int preallocate(BlockDriverState *bs,
ret = 0;
done:
qemu_co_mutex_unlock(&s->lock);
params->ret = ret;
}
static int preallocate(BlockDriverState *bs,
uint64_t offset, uint64_t new_length)
{
PreallocCo params = {
.bs = bs,
.offset = offset,
.new_length = new_length,
.ret = -EINPROGRESS,
};
if (qemu_in_coroutine()) {
qemu_co_mutex_unlock(&s->lock);
preallocate_co(&params);
} else {
Coroutine *co = qemu_coroutine_create(preallocate_co, &params);
bdrv_coroutine_enter(bs, co);
BDRV_POLL_WHILE(bs, params.ret == -EINPROGRESS);
}
return ret;
return params.ret;
}
/* qcow2_refcount_metadata_size: