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| author | Jonathan Brassow <jbrassow@redhat.com> | 2009-04-02 20:55:30 +0200 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-04-02 20:55:30 +0200 |
| commit | 7513c2a761d69d2a93f17146b3563527d3618ba0 (patch) | |
| tree | 375a14998a60a47b83962d5a497139112ec6e8e4 /include | |
| parent | dm exception store: separate type from instance (diff) | |
| download | linux-7513c2a761d69d2a93f17146b3563527d3618ba0.tar.xz linux-7513c2a761d69d2a93f17146b3563527d3618ba0.zip | |
dm raid1: add is_remote_recovering hook for clusters
The logging API needs an extra function to make cluster mirroring
possible. This new function allows us to check whether a mirror
region is being recovered on another machine in the cluster. This
helps us prevent simultaneous recovery I/O and process I/O to the
same locations on disk.
Cluster-aware log modules will implement this function. Single
machine log modules will not. So, there is no performance
penalty for single machine mirrors.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Acked-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/dm-dirty-log.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/dm-dirty-log.h b/include/linux/dm-dirty-log.h index 727602b686d4..5e8b11d88f6f 100644 --- a/include/linux/dm-dirty-log.h +++ b/include/linux/dm-dirty-log.h @@ -116,6 +116,16 @@ struct dm_dirty_log_type { */ int (*status)(struct dm_dirty_log *log, status_type_t status_type, char *result, unsigned maxlen); + + /* + * is_remote_recovering is necessary for cluster mirroring. It provides + * a way to detect recovery on another node, so we aren't writing + * concurrently. This function is likely to block (when a cluster log + * is used). + * + * Returns: 0, 1 + */ + int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region); }; int dm_dirty_log_type_register(struct dm_dirty_log_type *type); |