From: Joe Thornber <ejt@xxxxxxxxxx>
The all_io_entry for a bio must be incremented whilst the
dm_bio_prison_cell is held for both the virtual and physical blocks.
That cell locking wasn't occuring. This patch fixes this.
Also, now that the map function may add bios to a cell, process_bio() is
no longer the only thread that will do so. As such, we must replace
dm_cell_release_singleton calls with cell_defer_no_holder (renamed from
cell_defer_except). In every case cell_defer_no_holder is called the
bio in question is the cell holder. If there are no non-holder bio
entries then cell_defer_no_holder behaves identically to
dm_cell_release_singleton. If there *are* non-holder entries then
dm_cell_release_singleton was the wrong thing to call because those
entries must be deferred.
Signed-off-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/md/dm-thin.c | 97 ++++++++++++++++++++++++++++++-------------------
1 files changed, 59 insertions(+), 38 deletions(-)
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 058acf3..1cb6d34 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -368,11 +368,24 @@ static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
dm_thin_changed_this_transaction(tc->td);
}
+static void inc_all_io_entry(struct pool *pool, struct bio *bio)
+{
+ struct dm_thin_endio_hook *h;
+
+ if (bio->bi_rw & REQ_DISCARD)
+ return;
+
+ h = dm_get_mapinfo(bio)->ptr;
+ h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
+}
+
static void issue(struct thin_c *tc, struct bio *bio)
{
struct pool *pool = tc->pool;
unsigned long flags;
+ inc_all_io_entry(pool, bio);
+
if (!bio_triggers_commit(tc, bio)) {
generic_make_request(bio);
return;
@@ -513,17 +526,14 @@ static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell,
}
/*
- * Same as cell_defer above, except it omits one particular detainee,
- * a write bio that covers the block and has already been processed.
+ * Same as cell_defer except it omits the original holder of the cell.
*/
-static void cell_defer_except(struct thin_c *tc, struct dm_bio_prison_cell *cell)
+static void cell_defer_no_holder(struct thin_c *tc,
+ struct dm_bio_prison_cell *cell)
{
- struct bio_list bios;
struct pool *pool = tc->pool;
unsigned long flags;
- bio_list_init(&bios);
-
spin_lock_irqsave(&pool->lock, flags);
dm_cell_release_no_holder(cell, &pool->deferred_bios);
spin_unlock_irqrestore(&pool->lock, flags);
@@ -573,7 +583,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
* the bios in the cell.
*/
if (bio) {
- cell_defer_except(tc, m->cell);
+ cell_defer_no_holder(tc, m->cell);
bio_endio(bio, 0);
} else
cell_defer(tc, m->cell, m->data_block);
@@ -588,8 +598,8 @@ static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
struct thin_c *tc = m->tc;
bio_io_error(m->bio);
- cell_defer_except(tc, m->cell);
- cell_defer_except(tc, m->cell2);
+ cell_defer_no_holder(tc, m->cell);
+ cell_defer_no_holder(tc, m->cell2);
mempool_free(m, tc->pool->mapping_pool);
}
@@ -602,8 +612,8 @@ static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
else
bio_endio(m->bio, 0);
- cell_defer_except(tc, m->cell);
- cell_defer_except(tc, m->cell2);
+ cell_defer_no_holder(tc, m->cell);
+ cell_defer_no_holder(tc, m->cell2);
mempool_free(m, tc->pool->mapping_pool);
}
@@ -936,7 +946,7 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
*/
build_data_key(tc->td, lookup_result.block, &key2);
if (dm_bio_detain(tc->pool->prison, &key2, bio, &cell2)) {
- dm_cell_release_singleton(cell, bio);
+ cell_defer_no_holder(tc, cell);
break;
}
@@ -967,12 +977,13 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
* a block boundary. So we submit the discard of a
* partial block appropriately.
*/
- dm_cell_release_singleton(cell, bio);
- dm_cell_release_singleton(cell2, bio);
if ((!lookup_result.shared) && pool->pf.discard_passdown)
remap_and_issue(tc, bio, lookup_result.block);
else
bio_endio(bio, 0);
+
+ cell_defer_no_holder(tc, cell);
+ cell_defer_no_holder(tc, cell2);
}
break;
@@ -980,13 +991,13 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
/*
* It isn't provisioned, just forget it.
*/
- dm_cell_release_singleton(cell, bio);
+ cell_defer_no_holder(tc, cell);
bio_endio(bio, 0);
break;
default:
DMERR("discard: find block unexpectedly returned %d", r);
- dm_cell_release_singleton(cell, bio);
+ cell_defer_no_holder(tc, cell);
bio_io_error(bio);
break;
}
@@ -1041,8 +1052,8 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio,
h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
- dm_cell_release_singleton(cell, bio);
remap_and_issue(tc, bio, lookup_result->block);
+ cell_defer_no_holder(tc, cell);
}
}
@@ -1056,8 +1067,8 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
* Remap empty bios (flushes) immediately, without provisioning.
*/
if (!bio->bi_size) {
- dm_cell_release_singleton(cell, bio);
remap_and_issue(tc, bio, 0);
+ cell_defer_no_holder(tc, cell);
return;
}
@@ -1066,7 +1077,7 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
*/
if (bio_data_dir(bio) == READ) {
zero_fill_bio(bio);
- dm_cell_release_singleton(cell, bio);
+ cell_defer_no_holder(tc, cell);
bio_endio(bio, 0);
return;
}
@@ -1111,34 +1122,29 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
switch (r) {
case 0:
- /*
- * We can release this cell now. This thread is the only
- * one that puts bios into a cell, and we know there were
- * no preceding bios.
- */
- /*
- * TODO: this will probably have to change when discard goes
- * back in.
- */
- dm_cell_release_singleton(cell, bio);
-
if (lookup_result.shared)
process_shared_bio(tc, bio, block, &lookup_result);
else
remap_and_issue(tc, bio, lookup_result.block);
+
+ /*
+ * We can release this cell now. But there may be other
+ * other bios in the cell from the thin_map function.
+ */
+ cell_defer_no_holder(tc, cell);
break;
case -ENODATA:
if (bio_data_dir(bio) == READ && tc->origin_dev) {
- dm_cell_release_singleton(cell, bio);
remap_to_origin_and_issue(tc, bio);
+ cell_defer_no_holder(tc, cell);
} else
provision_block(tc, bio, block, cell);
break;
default:
DMERR("dm_thin_find_block() failed, error = %d", r);
- dm_cell_release_singleton(cell, bio);
+ cell_defer_no_holder(tc, cell);
bio_io_error(bio);
break;
}
@@ -1347,7 +1353,7 @@ static struct dm_thin_endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *b
h->tc = tc;
h->shared_read_entry = NULL;
- h->all_io_entry = bio->bi_rw & REQ_DISCARD ? NULL : dm_deferred_entry_inc(pool->all_io_ds);
+ h->all_io_entry = NULL;
h->overwrite_mapping = NULL;
return h;
@@ -1364,6 +1370,8 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio,
dm_block_t block = get_bio_block(tc, bio);
struct dm_thin_device *td = tc->td;
struct dm_thin_lookup_result result;
+ struct dm_bio_prison_cell *cell1, *cell2;
+ struct dm_cell_key key;
map_context->ptr = thin_hook_bio(tc, bio);
@@ -1400,12 +1408,25 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio,
* shared flag will be set in their case.
*/
thin_defer_bio(tc, bio);
- r = DM_MAPIO_SUBMITTED;
- } else {
- remap(tc, bio, result.block);
- r = DM_MAPIO_REMAPPED;
+ return DM_MAPIO_SUBMITTED;
}
- break;
+
+ build_virtual_key(tc->td, block, &key);
+ if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1))
+ return DM_MAPIO_SUBMITTED;
+
+ build_data_key(tc->td, result.block, &key);
+ if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2)) {
+ cell_defer_no_holder(tc, cell1);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ inc_all_io_entry(tc->pool, bio);
+ cell_defer_no_holder(tc, cell2);
+ cell_defer_no_holder(tc, cell1);
+
+ remap(tc, bio, result.block);
+ return DM_MAPIO_REMAPPED;
case -ENODATA:
if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
--
1.7.1
--
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