dm cache: the CLEAN_SHUTDOWN flag was not being set

If the CLEAN_SHUTDOWN flag is not set when a cache is loaded then all cache
blocks are marked as dirty and a full writeback occurs.

__commit_transaction() is responsible for setting/clearing
CLEAN_SHUTDOWN (based the flags_mutator that is passed in).

Fix this issue, of the cache's on-disk flags being wrong, by making sure
__commit_transaction() does not reset the flags after the mutator has
altered the flags in preparation for them being serialized to disk.

before:

sb_flags = mutator(le32_to_cpu(disk_super->flags));
disk_super->flags = cpu_to_le32(sb_flags);
disk_super->flags = cpu_to_le32(cmd->flags);

after:

disk_super->flags = cpu_to_le32(cmd->flags);
sb_flags = mutator(le32_to_cpu(disk_super->flags));
disk_super->flags = cpu_to_le32(sb_flags);

Reported-by: Bogdan Vasiliev <bogdan.vasiliev@gmail.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Joe Thornber 2015-10-22 18:10:55 +01:00 коммит произвёл Mike Snitzer
Родитель 4dcb8b57df
Коммит 3201ac452e
1 изменённых файлов: 1 добавлений и 1 удалений

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@ -634,10 +634,10 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
disk_super = dm_block_data(sblock);
disk_super->flags = cpu_to_le32(cmd->flags);
if (mutator)
update_flags(disk_super, mutator);
disk_super->flags = cpu_to_le32(cmd->flags);
disk_super->mapping_root = cpu_to_le64(cmd->root);
disk_super->hint_root = cpu_to_le64(cmd->hint_root);
disk_super->discard_root = cpu_to_le64(cmd->discard_root);