mirror: Switch mirror_iteration() to byte-based
We are gradually converting to byte-based interfaces, as they are
easier to reason about than sector-based. Change the internal
loop iteration of mirroring to track by bytes instead of sectors
(although we are still guaranteed that we iterate by steps that
are both sector-aligned and multiples of the granularity). Drop
the now-unused mirror_clip_sectors().
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/mirror.c b/block/mirror.c
index 262fddf..b33f4bb 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -184,15 +184,6 @@
return MIN(bytes, s->bdev_length - offset);
}
-/* Clip nb_sectors relative to sector_num to not exceed end-of-file */
-static inline int mirror_clip_sectors(MirrorBlockJob *s,
- int64_t sector_num,
- int nb_sectors)
-{
- return MIN(nb_sectors,
- s->bdev_length / BDRV_SECTOR_SIZE - sector_num);
-}
-
/* Round offset and/or bytes to target cluster if COW is needed, and
* return the offset of the adjusted tail against original. */
static int mirror_cow_align(MirrorBlockJob *s, int64_t *offset,
@@ -336,30 +327,28 @@
static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
{
BlockDriverState *source = s->source;
- int64_t sector_num, first_chunk;
+ int64_t offset, first_chunk;
uint64_t delay_ns = 0;
/* At least the first dirty chunk is mirrored in one iteration. */
int nb_chunks = 1;
- int64_t end = s->bdev_length / BDRV_SECTOR_SIZE;
int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));
int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);
bdrv_dirty_bitmap_lock(s->dirty_bitmap);
- sector_num = bdrv_dirty_iter_next(s->dbi);
- if (sector_num < 0) {
+ offset = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
+ if (offset < 0) {
bdrv_set_dirty_iter(s->dbi, 0);
- sector_num = bdrv_dirty_iter_next(s->dbi);
+ offset = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap) *
BDRV_SECTOR_SIZE);
- assert(sector_num >= 0);
+ assert(offset >= 0);
}
bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
- first_chunk = sector_num / sectors_per_chunk;
+ first_chunk = offset / s->granularity;
while (test_bit(first_chunk, s->in_flight_bitmap)) {
- trace_mirror_yield_in_flight(s, sector_num * BDRV_SECTOR_SIZE,
- s->in_flight);
+ trace_mirror_yield_in_flight(s, offset, s->in_flight);
mirror_wait_for_io(s);
}
@@ -368,25 +357,26 @@
/* Find the number of consective dirty chunks following the first dirty
* one, and wait for in flight requests in them. */
bdrv_dirty_bitmap_lock(s->dirty_bitmap);
- while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) {
+ while (nb_chunks * s->granularity < s->buf_size) {
int64_t next_dirty;
- int64_t next_sector = sector_num + nb_chunks * sectors_per_chunk;
- int64_t next_chunk = next_sector / sectors_per_chunk;
- if (next_sector >= end ||
- !bdrv_get_dirty_locked(source, s->dirty_bitmap, next_sector)) {
+ int64_t next_offset = offset + nb_chunks * s->granularity;
+ int64_t next_chunk = next_offset / s->granularity;
+ if (next_offset >= s->bdev_length ||
+ !bdrv_get_dirty_locked(source, s->dirty_bitmap,
+ next_offset >> BDRV_SECTOR_BITS)) {
break;
}
if (test_bit(next_chunk, s->in_flight_bitmap)) {
break;
}
- next_dirty = bdrv_dirty_iter_next(s->dbi);
- if (next_dirty > next_sector || next_dirty < 0) {
+ next_dirty = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
+ if (next_dirty > next_offset || next_dirty < 0) {
/* The bitmap iterator's cache is stale, refresh it */
- bdrv_set_dirty_iter(s->dbi, next_sector);
- next_dirty = bdrv_dirty_iter_next(s->dbi);
+ bdrv_set_dirty_iter(s->dbi, next_offset >> BDRV_SECTOR_BITS);
+ next_dirty = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
}
- assert(next_dirty == next_sector);
+ assert(next_dirty == next_offset);
nb_chunks++;
}
@@ -394,14 +384,15 @@
* calling bdrv_get_block_status_above could yield - if some blocks are
* marked dirty in this window, we need to know.
*/
- bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, sector_num,
- nb_chunks * sectors_per_chunk);
+ bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset >> BDRV_SECTOR_BITS,
+ nb_chunks * sectors_per_chunk);
bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
- bitmap_set(s->in_flight_bitmap, sector_num / sectors_per_chunk, nb_chunks);
- while (nb_chunks > 0 && sector_num < end) {
+ bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
+ while (nb_chunks > 0 && offset < s->bdev_length) {
int64_t ret;
int io_sectors;
+ unsigned int io_bytes;
int64_t io_bytes_acct;
BlockDriverState *file;
enum MirrorMethod {
@@ -410,28 +401,28 @@
MIRROR_METHOD_DISCARD
} mirror_method = MIRROR_METHOD_COPY;
- assert(!(sector_num % sectors_per_chunk));
- ret = bdrv_get_block_status_above(source, NULL, sector_num,
+ assert(!(offset % s->granularity));
+ ret = bdrv_get_block_status_above(source, NULL,
+ offset >> BDRV_SECTOR_BITS,
nb_chunks * sectors_per_chunk,
&io_sectors, &file);
+ io_bytes = io_sectors * BDRV_SECTOR_SIZE;
if (ret < 0) {
- io_sectors = MIN(nb_chunks * sectors_per_chunk,
- max_io_bytes >> BDRV_SECTOR_BITS);
+ io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);
} else if (ret & BDRV_BLOCK_DATA) {
- io_sectors = MIN(io_sectors, max_io_bytes >> BDRV_SECTOR_BITS);
+ io_bytes = MIN(io_bytes, max_io_bytes);
}
- io_sectors -= io_sectors % sectors_per_chunk;
- if (io_sectors < sectors_per_chunk) {
- io_sectors = sectors_per_chunk;
+ io_bytes -= io_bytes % s->granularity;
+ if (io_bytes < s->granularity) {
+ io_bytes = s->granularity;
} else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) {
- int64_t target_sector_num;
- int target_nb_sectors;
- bdrv_round_sectors_to_clusters(blk_bs(s->target), sector_num,
- io_sectors, &target_sector_num,
- &target_nb_sectors);
- if (target_sector_num == sector_num &&
- target_nb_sectors == io_sectors) {
+ int64_t target_offset;
+ unsigned int target_bytes;
+ bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes,
+ &target_offset, &target_bytes);
+ if (target_offset == offset &&
+ target_bytes == io_bytes) {
mirror_method = ret & BDRV_BLOCK_ZERO ?
MIRROR_METHOD_ZERO :
MIRROR_METHOD_DISCARD;
@@ -439,8 +430,7 @@
}
while (s->in_flight >= MAX_IN_FLIGHT) {
- trace_mirror_yield_in_flight(s, sector_num * BDRV_SECTOR_SIZE,
- s->in_flight);
+ trace_mirror_yield_in_flight(s, offset, s->in_flight);
mirror_wait_for_io(s);
}
@@ -448,30 +438,27 @@
return 0;
}
- io_sectors = mirror_clip_sectors(s, sector_num, io_sectors);
+ io_bytes = mirror_clip_bytes(s, offset, io_bytes);
switch (mirror_method) {
case MIRROR_METHOD_COPY:
- io_bytes_acct = mirror_do_read(s, sector_num * BDRV_SECTOR_SIZE,
- io_sectors * BDRV_SECTOR_SIZE);
- io_sectors = io_bytes_acct / BDRV_SECTOR_SIZE;
+ io_bytes = io_bytes_acct = mirror_do_read(s, offset, io_bytes);
break;
case MIRROR_METHOD_ZERO:
case MIRROR_METHOD_DISCARD:
- mirror_do_zero_or_discard(s, sector_num * BDRV_SECTOR_SIZE,
- io_sectors * BDRV_SECTOR_SIZE,
+ mirror_do_zero_or_discard(s, offset, io_bytes,
mirror_method == MIRROR_METHOD_DISCARD);
if (write_zeroes_ok) {
io_bytes_acct = 0;
} else {
- io_bytes_acct = io_sectors * BDRV_SECTOR_SIZE;
+ io_bytes_acct = io_bytes;
}
break;
default:
abort();
}
- assert(io_sectors);
- sector_num += io_sectors;
- nb_chunks -= DIV_ROUND_UP(io_sectors, sectors_per_chunk);
+ assert(io_bytes);
+ offset += io_bytes;
+ nb_chunks -= DIV_ROUND_UP(io_bytes, s->granularity);
if (s->common.speed) {
delay_ns = ratelimit_calculate_delay(&s->limit, io_bytes_acct);
}
