diff options
| author | Max Reitz <mreitz@redhat.com> | 2016-04-20 00:59:47 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2016-04-20 16:52:55 +0200 |
| commit | 9c83625bdd3c1900d304058ece152040ef5d1ead (patch) | |
| tree | 5e9e0b0ac950fd5c988096721ba1567cc752e38a | |
| parent | 4113b0532da6c448f8e458b413ebde035234d0ea (diff) | |
block/mirror: Revive dead yielding code
mirror_iteration() is supposed to wait if the current chunk is subject
to a still in-flight mirroring operation. However, it mixed checking
this conflict situation with checking the dirty status of a chunk. A
simplification for the latter condition (the first chunk encountered is
always dirty) led to neglecting the former: We just skip the first chunk
and thus never test whether it conflicts with an in-flight operation.
To fix this, pull out the code which waits for in-flight operations on
the first chunk of the range to be mirrored to settle.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| -rw-r--r-- | block/mirror.c | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/block/mirror.c b/block/mirror.c index c2cfc1a5ef..2714a77d69 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -298,7 +298,7 @@ static void mirror_do_zero_or_discard(MirrorBlockJob *s, static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) { BlockDriverState *source = s->common.bs; - int64_t sector_num; + int64_t sector_num, first_chunk; uint64_t delay_ns = 0; /* At least the first dirty chunk is mirrored in one iteration. */ int nb_chunks = 1; @@ -313,6 +313,12 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) assert(sector_num >= 0); } + first_chunk = sector_num / sectors_per_chunk; + while (test_bit(first_chunk, s->in_flight_bitmap)) { + trace_mirror_yield_in_flight(s, first_chunk, s->in_flight); + mirror_wait_for_io(s); + } + /* Find the number of consective dirty chunks following the first dirty * one, and wait for in flight requests in them. */ while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) { @@ -324,17 +330,12 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) break; } if (test_bit(next_chunk, s->in_flight_bitmap)) { - if (nb_chunks > 0) { - break; - } - trace_mirror_yield_in_flight(s, next_sector, s->in_flight); - mirror_wait_for_io(s); - /* Now retry. */ - } else { - hbitmap_next = hbitmap_iter_next(&s->hbi); - assert(hbitmap_next == next_sector); - nb_chunks++; + break; } + + hbitmap_next = hbitmap_iter_next(&s->hbi); + assert(hbitmap_next == next_sector); + nb_chunks++; } /* Clear dirty bits before querying the block status, because |