Skip to content

Commit

Permalink
parallels: Fix comments formatting inside parallels driver
Browse files Browse the repository at this point in the history
This patch is technically necessary as git patch rendering could result
in moving some code from one place to the another and that hits
checkpatch.pl warning. This problem specifically happens within next
series.

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Denis V. Lunev <den@openvz.org>
  • Loading branch information
AlexanderIvanov-Virtuozzo authored and Denis V. Lunev committed Sep 6, 2023
1 parent bb20ec6 commit a338dcb
Showing 1 changed file with 12 additions and 6 deletions.
18 changes: 12 additions & 6 deletions block/parallels.c
Original file line number Diff line number Diff line change
Expand Up @@ -188,15 +188,17 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
idx = sector_num / s->tracks;
to_allocate = DIV_ROUND_UP(sector_num + *pnum, s->tracks) - idx;

/* This function is called only by parallels_co_writev(), which will never
/*
* This function is called only by parallels_co_writev(), which will never
* pass a sector_num at or beyond the end of the image (because the block
* layer never passes such a sector_num to that function). Therefore, idx
* is always below s->bat_size.
* block_status() will limit *pnum so that sector_num + *pnum will not
* exceed the image end. Therefore, idx + to_allocate cannot exceed
* s->bat_size.
* Note that s->bat_size is an unsigned int, therefore idx + to_allocate
* will always fit into a uint32_t. */
* will always fit into a uint32_t.
*/
assert(idx < s->bat_size && idx + to_allocate <= s->bat_size);

space = to_allocate * s->tracks;
Expand Down Expand Up @@ -230,13 +232,15 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
}
}

/* Try to read from backing to fill empty clusters
/*
* Try to read from backing to fill empty clusters
* FIXME: 1. previous write_zeroes may be redundant
* 2. most of data we read from backing will be rewritten by
* parallels_co_writev. On aligned-to-cluster write we do not need
* this read at all.
* 3. it would be good to combine write of data from backing and new
* data into one write call */
* data into one write call.
*/
if (bs->backing) {
int64_t nb_cow_sectors = to_allocate * s->tracks;
int64_t nb_cow_bytes = nb_cow_sectors << BDRV_SECTOR_BITS;
Expand Down Expand Up @@ -864,8 +868,10 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
s->data_end = ROUND_UP(bat_entry_off(s->bat_size), BDRV_SECTOR_SIZE);
}
if (s->data_end < s->header_size) {
/* there is not enough unused space to fit to block align between BAT
and actual data. We can't avoid read-modify-write... */
/*
* There is not enough unused space to fit to block align between BAT
* and actual data. We can't avoid read-modify-write...
*/
s->header_size = size;
}

Expand Down

0 comments on commit a338dcb

Please sign in to comment.