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| author | Mike Snitzer <snitzer@redhat.com> | 2018-08-02 16:08:52 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2018-08-07 14:30:30 -0400 |
| commit | fd2fa95416188a767a63979296fa3e169a9ef5ec (patch) | |
| tree | 18fcd992ce788f48fd53964edaf3fa0d05ebb4c8 | |
| parent | 75294442d896f2767be34f75aca7cc2b0d01301f (diff) | |
| download | linux-fd2fa95416188a767a63979296fa3e169a9ef5ec.tar.gz linux-fd2fa95416188a767a63979296fa3e169a9ef5ec.tar.bz2 linux-fd2fa95416188a767a63979296fa3e169a9ef5ec.zip | |
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.c | 3 |
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); |