| Message ID | 20210724133846.64614-3-vsementsov@virtuozzo.com |
|---|---|
| State | New |
| Headers | show |
| Series | qcow2: relax subclusters allocation dependencies | expand |
On Sat, Jul 24, 2021 at 04:38:45PM +0300, Vladimir Sementsov-Ogievskiy wrote: > No logic change, just prepare for the following commit. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > block/qcow2-cluster.c | 49 ++++++++++++++++++++++++------------------- > 1 file changed, 28 insertions(+), 21 deletions(-) > > diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c > index bd0597842f..967121c7e6 100644 > --- a/block/qcow2-cluster.c > +++ b/block/qcow2-cluster.c > @@ -1400,29 +1400,36 @@ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset, > > if (end <= old_start || start >= old_end) { > /* No intersection */ > - } else { > - if (start < old_start) { > - /* Stop at the start of a running allocation */ > - bytes = old_start - start; > - } else { > - bytes = 0; > - } > + continue; > + } > > - /* Stop if already an l2meta exists. After yielding, it wouldn't Pre-existing, but... > - * be valid any more, so we'd have to clean up the old L2Metas > - * and deal with requests depending on them before starting to > - * gather new ones. Not worth the trouble. */ > - if (bytes == 0 && *m) { > - *cur_bytes = 0; > - return 0; > - } > + /* Conflict */ > > - if (bytes == 0) { > - /* Wait for the dependency to complete. We need to recheck > - * the free/allocated clusters when we continue. */ > - qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock); > - return -EAGAIN; > - } > + if (start < old_start) { > + /* Stop at the start of a running allocation */ > + bytes = old_start - start; > + } else { > + bytes = 0; > + } > + > + /* > + * Stop if already an l2meta exists. After yielding, it wouldn't ...might as well fix the grammar: Stop if an l2meta already exists. > + * be valid any more, so we'd have to clean up the old L2Metas > + * and deal with requests depending on them before starting to > + * gather new ones. Not worth the trouble. > + */ > + if (bytes == 0 && *m) { > + *cur_bytes = 0; > + return 0; > + } > + > + if (bytes == 0) { > + /* > + * Wait for the dependency to complete. We need to recheck > + * the free/allocated clusters when we continue. > + */ > + qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock); > + return -EAGAIN; So the change adds a short-circuiting 'continue', then reduces the indentation of the rest of the loop body. Reviewed-by: Eric Blake <eblake@redhat.com>
On 24.07.21 15:38, Vladimir Sementsov-Ogievskiy wrote: > No logic change, just prepare for the following commit. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > block/qcow2-cluster.c | 49 ++++++++++++++++++++++++------------------- > 1 file changed, 28 insertions(+), 21 deletions(-) Reviewed-by: Hanna Reitz <hreitz@redhat.com>
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index bd0597842f..967121c7e6 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1400,29 +1400,36 @@ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset, if (end <= old_start || start >= old_end) { /* No intersection */ - } else { - if (start < old_start) { - /* Stop at the start of a running allocation */ - bytes = old_start - start; - } else { - bytes = 0; - } + continue; + } - /* Stop if already an l2meta exists. After yielding, it wouldn't - * be valid any more, so we'd have to clean up the old L2Metas - * and deal with requests depending on them before starting to - * gather new ones. Not worth the trouble. */ - if (bytes == 0 && *m) { - *cur_bytes = 0; - return 0; - } + /* Conflict */ - if (bytes == 0) { - /* Wait for the dependency to complete. We need to recheck - * the free/allocated clusters when we continue. */ - qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock); - return -EAGAIN; - } + if (start < old_start) { + /* Stop at the start of a running allocation */ + bytes = old_start - start; + } else { + bytes = 0; + } + + /* + * Stop if already an l2meta exists. After yielding, it wouldn't + * be valid any more, so we'd have to clean up the old L2Metas + * and deal with requests depending on them before starting to + * gather new ones. Not worth the trouble. + */ + if (bytes == 0 && *m) { + *cur_bytes = 0; + return 0; + } + + if (bytes == 0) { + /* + * Wait for the dependency to complete. We need to recheck + * the free/allocated clusters when we continue. + */ + qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock); + return -EAGAIN; } }
No logic change, just prepare for the following commit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- block/qcow2-cluster.c | 49 ++++++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 21 deletions(-)