Otherwise, just loading a thin-pool and then removing it will cause its
metadata to be changed (e.g. superblock written) -- even without any
thin devices being made active or metadata snapshot being manipulated.
Add 'in_service' flag to struct dm_pool_metadata and use a new
dm_pool_set_in_service() interface to set it if either a thin device is
activated or a message is sent to the thin-pool. Once 'in_service' is
set it is never cleared. __commit_transaction() will return 0 if
'in_service' is not set.
Also fix dm_pool_commit_metadata() to open the next transaction if the
return from __commit_transaction() is 0. Not seeing why the early
return ever made since for a return of 0 given that dm-io's async_io(),
as used by bufio, always returns 0.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-thin-metadata.c | 23 ++++++++++++++++++++++-
drivers/md/dm-thin-metadata.h | 2 ++
drivers/md/dm-thin.c | 9 +++++++++
3 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 7381e477a945..fcff30fc07cd 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -201,6 +201,13 @@ struct dm_pool_metadata {
*/
bool fail_io:1;
+ /*
+ * Set once a thin-pool has been accessed through one of the interfaces
+ * that imply the pool is in-service (e.g. thin devices created/deleted,
+ * thin-pool message, metadata snapshots, etc).
+ */
+ bool in_service:1;
+
/*
* Reading the space map roots can fail, so we read it into these
* buffers before the superblock is locked and updated.
@@ -790,6 +797,9 @@ static int __commit_transaction(struct dm_pool_metadata *pmd)
*/
BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
+ if (unlikely(!pmd->in_service))
+ return 0;
+
r = __write_changed_details(pmd);
if (r < 0)
return r;
@@ -853,6 +863,7 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
pmd->time = 0;
INIT_LIST_HEAD(&pmd->thin_devices);
pmd->fail_io = false;
+ pmd->in_service = false;
pmd->bdev = bdev;
pmd->data_block_size = data_block_size;
@@ -1727,6 +1738,16 @@ int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_
return r;
}
+void dm_pool_set_in_service(struct dm_pool_metadata *pmd)
+{
+ if (!pmd->in_service) {
+ down_write(&pmd->root_lock);
+ if (!pmd->in_service)
+ pmd->in_service = true;
+ up_write(&pmd->root_lock);
+ }
+}
+
bool dm_thin_changed_this_transaction(struct dm_thin_device *td)
{
int r;
@@ -1787,7 +1808,7 @@ int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
goto out;
r = __commit_transaction(pmd);
- if (r <= 0)
+ if (r < 0)
goto out;
/*
diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h
index f6be0d733c20..8192530984be 100644
--- a/drivers/md/dm-thin-metadata.h
+++ b/drivers/md/dm-thin-metadata.h
@@ -47,6 +47,8 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
int dm_pool_metadata_close(struct dm_pool_metadata *pmd);
+void dm_pool_set_in_service(struct dm_pool_metadata *pmd);
+
/*
* Compat feature flags. Any incompat flags beyond the ones
* specified below will prevent use of the thin metadata.
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index fcd887703f95..b6dbbdfc9118 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3822,6 +3822,13 @@ static int pool_message(struct dm_target *ti, unsigned argc, char **argv,
return -EOPNOTSUPP;
}
+ /*
+ * Any message sent to a thin-pool warrants putting it in-service
+ * (even if the message is malformed, it speaks to a user
+ * attempting to interface with the thin-pool)
+ */
+ dm_pool_set_in_service(pool->pmd);
+
if (!strcasecmp(argv[0], "create_thin"))
r = process_create_thin_mesg(argc, argv, pool);
@@ -4222,6 +4229,8 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
goto bad_pool;
}
+ dm_pool_set_in_service(tc->pool->pmd);
+
r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
if (r) {
ti->error = "Couldn't open thin internal device";
--
2.18.0
--
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