From 12ba58af46e5973822f1cfaaf5f29a2a17a523bf Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Fri, 27 Jul 2012 15:08:15 +0100 Subject: [PATCH] dm thin metadata: introduce dm_pool_metadata_set_read_only Introduce dm_pool_metadata_set_read_only to put the underlying block manager into read-only mode. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon --- drivers/md/dm-thin-metadata.c | 20 ++++++++++++++++---- drivers/md/dm-thin-metadata.h | 6 ++++++ 2 files changed, 22 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index 4f5b11c..d30bc09 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -184,6 +184,7 @@ struct dm_pool_metadata { uint64_t trans_id; unsigned long flags; sector_t data_block_size; + bool read_only:1; }; struct dm_thin_device { @@ -807,6 +808,7 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, init_rwsem(&pmd->root_lock); pmd->time = 0; INIT_LIST_HEAD(&pmd->thin_devices); + pmd->read_only = false; pmd->bdev = bdev; pmd->data_block_size = data_block_size; @@ -849,10 +851,12 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd) return -EBUSY; } - r = __commit_transaction(pmd); - if (r < 0) - DMWARN("%s: __commit_transaction() failed, error = %d", - __func__, r); + if (!pmd->read_only) { + r = __commit_transaction(pmd); + if (r < 0) + DMWARN("%s: __commit_transaction() failed, error = %d", + __func__, r); + } __destroy_persistent_data_objects(pmd); kfree(pmd); @@ -1587,3 +1591,11 @@ int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count) return r; } + +void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd) +{ + down_write(&pmd->root_lock); + pmd->read_only = true; + dm_bm_set_read_only(pmd->bm); + up_write(&pmd->root_lock); +} diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h index 1632fec..2bbe622 100644 --- a/drivers/md/dm-thin-metadata.h +++ b/drivers/md/dm-thin-metadata.h @@ -174,6 +174,12 @@ int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result); */ int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); +/* + * Flicks the underlying block manager into read only mode, so you know + * that nothing is changing. + */ +void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd); + /*----------------------------------------------------------------*/ #endif -- 2.7.4