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authorMike Snitzer <snitzer@redhat.com>2018-08-02 16:08:52 -0400
committerMike Snitzer <snitzer@redhat.com>2018-08-07 14:30:30 -0400
commitfd2fa95416188a767a63979296fa3e169a9ef5ec (patch)
tree18fcd992ce788f48fd53964edaf3fa0d05ebb4c8
parent75294442d896f2767be34f75aca7cc2b0d01301f (diff)
downloadlinux-fd2fa95416188a767a63979296fa3e169a9ef5ec.tar.bz2
dm cache metadata: save in-core policy_hint_size to on-disk superblock
policy_hint_size starts as 0 during __write_initial_superblock(). It isn't until the policy is loaded that policy_hint_size is set in-core (cmd->policy_hint_size). But it never got recorded in the on-disk superblock because __commit_transaction() didn't deal with transfering the in-core cmd->policy_hint_size to the on-disk superblock. The in-core cmd->policy_hint_size gets initialized by metadata_open()'s __begin_transaction_flags() which re-reads all superblock fields. Because the superblock's policy_hint_size was never properly stored, when the cache was created, hints_array_available() would always return false when re-activating a previously created cache. This means __load_mappings() always considered the hints invalid and never made use of the hints (these hints served to optimize). Another detremental side-effect of this oversight is the cache_check utility would fail with: "invalid hint width: 0" Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-rw-r--r--drivers/md/dm-cache-metadata.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 0d7212410e21..1a449105b007 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -363,7 +363,7 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
disk_super->version = cpu_to_le32(cmd->version);
memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
- disk_super->policy_hint_size = 0;
+ disk_super->policy_hint_size = cpu_to_le32(0);
__copy_sm_root(cmd, disk_super);
@@ -701,6 +701,7 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
+ disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size);
disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);