@@ -1504,6 +1504,14 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_SUBMITTED;
}
+ /*
+ * We must hold the virtual cell before doing the lookup, otherwise
+ * there's a race with discard.
+ */
+ build_virtual_key(tc->td, block, &key);
+ if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
+ return DM_MAPIO_SUBMITTED;
+
r = dm_thin_find_block(td, block, 0, &result);
/*
@@ -1527,13 +1535,10 @@ 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);
+ cell_defer_no_holder_no_free(tc, &cell1);
return DM_MAPIO_SUBMITTED;
}
- build_virtual_key(tc->td, block, &key);
- if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
- return DM_MAPIO_SUBMITTED;
-
build_data_key(tc->td, result.block, &key);
if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
cell_defer_no_holder_no_free(tc, &cell1);
@@ -1554,6 +1559,7 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
* of doing so. Just error it.
*/
bio_io_error(bio);
+ cell_defer_no_holder_no_free(tc, &cell1);
return DM_MAPIO_SUBMITTED;
}
/* fall through */
@@ -1564,6 +1570,7 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
* provide the hint to load the metadata into cache.
*/
thin_defer_bio(tc, bio);
+ cell_defer_no_holder_no_free(tc, &cell1);
return DM_MAPIO_SUBMITTED;
default:
@@ -1573,6 +1580,7 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
* pool is switched to fail-io mode.
*/
bio_io_error(bio);
+ cell_defer_no_holder_no_free(tc, &cell1);
return DM_MAPIO_SUBMITTED;
}
}