On Wed, Dec 04 2019 at 9:07P -0500,
Nikos Tsironis <ntsironis@xxxxxxxxxxx> wrote:
> Add support for one pre-commit callback which is run right before the
> metadata are committed.
>
> This allows the thin provisioning target to run a callback before the
> metadata are committed and is required by the next commit.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Nikos Tsironis <ntsironis@xxxxxxxxxxx>
> ---
> drivers/md/dm-thin-metadata.c | 29 +++++++++++++++++++++++++++++
> drivers/md/dm-thin-metadata.h | 7 +++++++
> 2 files changed, 36 insertions(+)
>
> diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
> index 4c68a7b93d5e..b88d6d701f5b 100644
> --- a/drivers/md/dm-thin-metadata.c
> +++ b/drivers/md/dm-thin-metadata.c
> @@ -189,6 +189,15 @@ struct dm_pool_metadata {
> sector_t data_block_size;
>
> /*
> + * Pre-commit callback.
> + *
> + * This allows the thin provisioning target to run a callback before
> + * the metadata are committed.
> + */
> + dm_pool_pre_commit_fn pre_commit_fn;
> + void *pre_commit_context;
> +
> + /*
> * We reserve a section of the metadata for commit overhead.
> * All reported space does *not* include this.
> */
> @@ -826,6 +835,14 @@ static int __commit_transaction(struct dm_pool_metadata *pmd)
> if (unlikely(!pmd->in_service))
> return 0;
>
> + if (pmd->pre_commit_fn) {
> + r = pmd->pre_commit_fn(pmd->pre_commit_context);
> + if (r < 0) {
> + DMERR("pre-commit callback failed");
> + return r;
> + }
> + }
> +
> r = __write_changed_details(pmd);
> if (r < 0)
> return r;
> @@ -892,6 +909,8 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
> pmd->in_service = false;
> pmd->bdev = bdev;
> pmd->data_block_size = data_block_size;
> + pmd->pre_commit_fn = NULL;
> + pmd->pre_commit_context = NULL;
>
> r = __create_persistent_data_objects(pmd, format_device);
> if (r) {
> @@ -2044,6 +2063,16 @@ int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
> return r;
> }
>
> +void dm_pool_register_pre_commit_callback(struct dm_pool_metadata *pmd,
> + dm_pool_pre_commit_fn fn,
> + void *context)
> +{
> + pmd_write_lock_in_core(pmd);
> + pmd->pre_commit_fn = fn;
> + pmd->pre_commit_context = context;
> + pmd_write_unlock(pmd);
> +}
> +
> int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd)
> {
> int r = -EINVAL;
> diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h
> index f6be0d733c20..7ef56bd2a7e3 100644
> --- a/drivers/md/dm-thin-metadata.h
> +++ b/drivers/md/dm-thin-metadata.h
> @@ -230,6 +230,13 @@ bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd);
> */
> void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd);
>
> +/* Pre-commit callback */
> +typedef int (*dm_pool_pre_commit_fn)(void *context);
> +
> +void dm_pool_register_pre_commit_callback(struct dm_pool_metadata *pmd,
> + dm_pool_pre_commit_fn fn,
> + void *context);
> +
> /*----------------------------------------------------------------*/
>
> #endif
> --
> 2.11.0
>
I have this incremental, not seeing need to avoid using blkdev_issue_flush
---
drivers/md/dm-thin.c | 12 +-----------
1 file changed, 1 insertion(+), 11 deletions(-)
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 9c9a323c0c30..255a52f7bbf0 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3203,18 +3203,8 @@ static void metadata_low_callback(void *context)
static int metadata_pre_commit_callback(void *context)
{
struct pool_c *pt = context;
- struct bio bio;
- int r;
-
- bio_init(&bio, NULL, 0);
- bio_set_dev(&bio, pt->data_dev->bdev);
- bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
-
- r = submit_bio_wait(&bio);
- bio_uninit(&bio);
-
- return r;
+ return blkdev_issue_flush(pt->data_dev->bdev, GFP_NOIO, NULL);
}
static sector_t get_dev_size(struct block_device *bdev)
--
2.15.0
--
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