[dm-devel] [PATCH 1/2] dm era: allocate in-core writesets when loading metadata

[Nikos Tsironis <ntsironis@arrikto.com>]

Until now, the allocation of the in-core bitmaps was done in pre-resume
by metadata_resize().

In preparation for the next commit, which makes it possible for a
metadata operation, e.g. an era rollover, to run before pre-resume runs,
allocate the in-core bitmaps as part of opening the metadata.

Also, set the number of blocks of the era device in era_ctr() to the
number of blocks in the metadata.

This avoids attempting to resize the metadata every time we create a new
target instance, even if the metadata size hasn't changed.

Fixes: eec40579d8487 ("dm: add era target")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
---
 drivers/md/dm-era-target.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/md/dm-era-target.c b/drivers/md/dm-era-target.c
index e92c1afc3677..3332bed2f412 100644
--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -788,6 +788,7 @@ static int metadata_digest_start(struct era_metadata *md, struct digest *d)
  * High level metadata interface.  Target methods should use these, and not
  * the lower level ones.
  *--------------------------------------------------------------*/
+static void metadata_close(struct era_metadata *md);
 static struct era_metadata *metadata_open(struct block_device *bdev,
 					  sector_t block_size,
 					  bool may_format)
@@ -811,6 +812,24 @@ static struct era_metadata *metadata_open(struct block_device *bdev,
 		return ERR_PTR(r);
 	}
 
+	if (md->nr_blocks == 0)
+		return md;
+
+	/* Allocate in-core writesets */
+	r = writeset_alloc(&md->writesets[0], md->nr_blocks);
+	if (r) {
+		DMERR("%s: writeset_alloc failed for writeset 0", __func__);
+		metadata_close(md);
+		return ERR_PTR(r);
+	}
+
+	r = writeset_alloc(&md->writesets[1], md->nr_blocks);
+	if (r) {
+		DMERR("%s: writeset_alloc failed for writeset 1", __func__);
+		metadata_close(md);
+		return ERR_PTR(r);
+	}
+
 	return md;
 }
 
@@ -1504,6 +1523,7 @@ static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		return PTR_ERR(md);
 	}
 	era->md = md;
+	era->nr_blocks = md->nr_blocks;
 
 	era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
 	if (!era->wq) {
-- 
2.30.2

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