===================================================================
@@ -285,8 +285,12 @@ static void do_region(int rw, unsigned r
unsigned offset;
unsigned num_bvecs;
sector_t remaining = where->count;
+ /*
+ * "count" may be zero when "rw" indicates a write barrier request.
+ * In this case, we must send a zero-sized barrier.
+ */
- while (remaining) {
+ do {
/*
* Allocate a suitably sized-bio: we add an extra
* bvec for bio_get/set_region() and decrement bi_max_vecs
@@ -323,7 +327,7 @@ static void do_region(int rw, unsigned r
atomic_inc(&io->count);
submit_bio(rw, bio);
- }
+ } while (remaining);
}
static void dispatch_io(int rw, unsigned int num_regions,
@@ -342,7 +346,7 @@ static void dispatch_io(int rw, unsigned
*/
for (i = 0; i < num_regions; i++) {
*dp = old_pages;
- if (where[i].count)
+ if (where[i].count || (rw & (1 << BIO_RW_BARRIER)))
do_region(rw, i, where + i, dp, io);
}
Accept empty barriers in dm-io. dm-io will process empty write barrier requests just like the other read/write requests. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> --- drivers/md/dm-io.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel