vitalif
/
mirror_qemu
mirror of https://github.com/proxmox/mirror_qemu
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

mirror: Don't let an operation wait for itself 

mirror_wait_for_free_in_flight_slot() just picks a random operation to
wait for. However, when mirror_co_read() waits for free slots, its
MirrorOp is already in s->ops_in_flight, so if not enough slots are
immediately available, an operation can end up waiting for itself to
complete, which results in a hang.

Fix this by passing the current MirrorOp and skipping this operation
when picking an operation to wait for.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1794692
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
master
Kevin Wolf 2020-01-28 16:09:28 +01:00
parent eed325b92c
commit 7e6c4ff792
1 changed files with 12 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
block/mirror.c
View File

@ -283,11 +283,14 @@ static int mirror_cow_align(MirrorBlockJob *s, int64_t *offset,
}
static inline void coroutine_fn
mirror_wait_for_any_operation(MirrorBlockJob *s, bool active)
mirror_wait_for_any_operation(MirrorBlockJob *s, MirrorOp *self, bool active)
{
MirrorOp *op;
QTAILQ_FOREACH(op, &s->ops_in_flight, next) {
if (self == op) {
continue;
}
/* Do not wait on pseudo ops, because it may in turn wait on
* some other operation to start, which may in fact be the
* caller of this function. Since there is only one pseudo op
@ -302,10 +305,10 @@ mirror_wait_for_any_operation(MirrorBlockJob *s, bool active)
}
static inline void coroutine_fn
mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s)
mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s, MirrorOp *self)
{
/* Only non-active operations use up in-flight slots */
mirror_wait_for_any_operation(s, false);
mirror_wait_for_any_operation(s, self, false);
}
/* Perform a mirror copy operation.
@ -348,7 +351,7 @@ static void coroutine_fn mirror_co_read(void *opaque)
while (s->buf_free_count < nb_chunks) {
trace_mirror_yield_in_flight(s, op->offset, s->in_flight);
mirror_wait_for_free_in_flight_slot(s);
mirror_wait_for_free_in_flight_slot(s, op);
}
/* Now make a QEMUIOVector taking enough granularity-sized chunks
@ -555,7 +558,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
while (s->in_flight >= MAX_IN_FLIGHT) {
trace_mirror_yield_in_flight(s, offset, s->in_flight);
mirror_wait_for_free_in_flight_slot(s);
mirror_wait_for_free_in_flight_slot(s, pseudo_op);
}
if (s->ret < 0) {
@ -609,7 +612,7 @@ static void mirror_free_init(MirrorBlockJob *s)
static void coroutine_fn mirror_wait_for_all_io(MirrorBlockJob *s)
{
while (s->in_flight > 0) {
mirror_wait_for_free_in_flight_slot(s);
mirror_wait_for_free_in_flight_slot(s, NULL);
}
}
@ -794,7 +797,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
if (s->in_flight >= MAX_IN_FLIGHT) {
trace_mirror_yield(s, UINT64_MAX, s->buf_free_count,
s->in_flight);
mirror_wait_for_free_in_flight_slot(s);
mirror_wait_for_free_in_flight_slot(s, NULL);
continue;
}
@ -947,7 +950,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp)
/* Do not start passive operations while there are active
* writes in progress */
while (s->in_active_write_counter) {
mirror_wait_for_any_operation(s, true);
mirror_wait_for_any_operation(s, NULL, true);
}
if (s->ret < 0) {
@ -973,7 +976,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp)
if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
(cnt == 0 && s->in_flight > 0)) {
trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight);
mirror_wait_for_free_in_flight_slot(s);
mirror_wait_for_free_in_flight_slot(s, NULL);
continue;
} else if (cnt != 0) {
delay_ns = mirror_iteration(s);