From: Joe Thornber <ejt@xxxxxxxxxx>
There is little benefit to doing this but it does structure DM thinp's
code to more cleanly use the __blkdev_issue_discard() interface --
particularly in passdown_double_checking_shared_status().
Signed-off-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-thin.c | 104 ++++++++++++++++++++++++++++++++++-----------------
1 file changed, 69 insertions(+), 35 deletions(-)
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 598a78b..e4bb9da 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -334,26 +334,55 @@ static sector_t block_to_sectors(struct pool *pool, dm_block_t b)
(b * pool->sectors_per_block);
}
-static int issue_discard(struct thin_c *tc, dm_block_t data_b, dm_block_t data_e,
- struct bio *parent_bio)
+/*----------------------------------------------------------------*/
+
+struct discard_op {
+ struct thin_c *tc;
+ struct blk_plug plug;
+ struct bio *parent_bio;
+ struct bio *bio;
+};
+
+static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent)
+{
+ BUG_ON(!parent);
+
+ op->tc = tc;
+ blk_start_plug(&op->plug);
+ op->parent_bio = parent;
+ op->bio = NULL;
+}
+
+static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e)
{
- int type = REQ_WRITE | REQ_DISCARD;
+ struct thin_c *tc = op->tc;
sector_t s = block_to_sectors(tc->pool, data_b);
sector_t len = block_to_sectors(tc->pool, data_e - data_b);
- struct bio *bio = NULL;
- struct blk_plug plug;
- int ret;
- blk_start_plug(&plug);
- ret = __blkdev_issue_discard(tc->pool_dev->bdev, s, len,
- GFP_NOWAIT, type, &bio);
- if (!ret && bio) {
- bio_chain(bio, parent_bio);
- submit_bio(type, bio);
+ return __blkdev_issue_discard(tc->pool_dev->bdev, s, len,
+ GFP_NOWAIT, REQ_WRITE | REQ_DISCARD, &op->bio);
+}
+
+static void end_discard(struct discard_op *op, int r)
+{
+ if (op->bio) {
+ /*
+ * Even if one of the calls to issue_discard failed, we
+ * need to wait for the chain to complete.
+ */
+ bio_chain(op->bio, op->parent_bio);
+ submit_bio(REQ_WRITE | REQ_DISCARD, op->bio);
}
- blk_finish_plug(&plug);
- return ret;
+ blk_finish_plug(&op->plug);
+
+ /*
+ * Even if r is set, there could be sub discards in flight that we
+ * need to wait for.
+ */
+ if (r && !op->parent_bio->bi_error)
+ op->parent_bio->bi_error = r;
+ bio_endio(op->parent_bio);
}
/*----------------------------------------------------------------*/
@@ -968,24 +997,28 @@ static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m)
mempool_free(m, tc->pool->mapping_pool);
}
-static int passdown_double_checking_shared_status(struct dm_thin_new_mapping *m)
+/*----------------------------------------------------------------*/
+
+static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m)
{
/*
* We've already unmapped this range of blocks, but before we
* passdown we have to check that these blocks are now unused.
*/
- int r;
+ int r = 0;
bool used = true;
struct thin_c *tc = m->tc;
struct pool *pool = tc->pool;
dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
+ struct discard_op op;
+ begin_discard(&op, tc, m->bio);
while (b != end) {
/* find start of unmapped run */
for (; b < end; b++) {
r = dm_pool_block_is_used(pool->pmd, b, &used);
if (r)
- return r;
+ goto out;
if (!used)
break;
@@ -998,20 +1031,20 @@ static int passdown_double_checking_shared_status(struct dm_thin_new_mapping *m)
for (e = b + 1; e != end; e++) {
r = dm_pool_block_is_used(pool->pmd, e, &used);
if (r)
- return r;
+ goto out;
if (used)
break;
}
- r = issue_discard(tc, b, e, m->bio);
+ r = issue_discard(&op, b, e);
if (r)
- return r;
+ goto out;
b = e;
}
-
- return 0;
+out:
+ end_discard(&op, r);
}
static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
@@ -1021,20 +1054,21 @@ static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
struct pool *pool = tc->pool;
r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end);
- if (r)
+ if (r) {
metadata_operation_failed(pool, "dm_thin_remove_range", r);
+ bio_io_error(m->bio);
- else if (m->maybe_shared)
- r = passdown_double_checking_shared_status(m);
- else
- r = issue_discard(tc, m->data_block, m->data_block + (m->virt_end - m->virt_begin), m->bio);
+ } else if (m->maybe_shared) {
+ passdown_double_checking_shared_status(m);
+
+ } else {
+ struct discard_op op;
+ begin_discard(&op, tc, m->bio);
+ r = issue_discard(&op, m->data_block,
+ m->data_block + (m->virt_end - m->virt_begin));
+ end_discard(&op, r);
+ }
- /*
- * Even if r is set, there could be sub discards in flight that we
- * need to wait for.
- */
- m->bio->bi_error = r;
- bio_endio(m->bio);
cell_defer_no_holder(tc, m->cell);
mempool_free(m, pool->mapping_pool);
}
@@ -1505,11 +1539,11 @@ static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t
/*
* The parent bio must not complete before sub discard bios are
- * chained to it (see issue_discard's bio_chain)!
+ * chained to it (see end_discard's bio_chain)!
*
* This per-mapping bi_remaining increment is paired with
* the implicit decrement that occurs via bio_endio() in
- * process_prepared_discard_passdown().
+ * end_discard().
*/
bio_inc_remaining(bio);
if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
--
2.6.4 (Apple Git-63)
--
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