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| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-12-11 00:52:08 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-12-11 00:52:08 +0100 |
| commit | 7e201b35132a1f02c931a0a06760766c846bb49b (patch) | |
| tree | 02ab2bcf4609763ab9780db2a87b9f37aa77186f /drivers/md/dm-snap.c | |
| parent | dm snapshot: simplify sector_to_chunk expression (diff) | |
| download | linux-7e201b35132a1f02c931a0a06760766c846bb49b.tar.xz linux-7e201b35132a1f02c931a0a06760766c846bb49b.zip | |
dm snapshot: abstract minimum_chunk_size fn
The origin needs to find minimum chunksize of all snapshots. This logic is
moved to a separate function because it will be used at another place in
the snapshot merge patches.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-snap.c')
| -rw-r--r-- | drivers/md/dm-snap.c | 34 |
1 files changed, 22 insertions, 12 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 8a4a9c838afd..48978ab42ae5 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -523,6 +523,25 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new) return 0; } +#define min_not_zero(l, r) (((l) == 0) ? (r) : (((r) == 0) ? (l) : min(l, r))) + +/* + * Return a minimum chunk size of all snapshots that have the specified origin. + * Return zero if the origin has no snapshots. + */ +static sector_t __minimum_chunk_size(struct origin *o) +{ + struct dm_snapshot *snap; + unsigned chunk_size = 0; + + if (o) + list_for_each_entry(snap, &o->snapshots, list) + chunk_size = min_not_zero(chunk_size, + snap->store->chunk_size); + + return chunk_size; +} + /* * Hard coded magic. */ @@ -1395,8 +1414,6 @@ static int origin_map(struct dm_target *ti, struct bio *bio, return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; } -#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) - /* * Set the target "split_io" field to the minimum of all the snapshots' * chunk sizes. @@ -1404,19 +1421,12 @@ static int origin_map(struct dm_target *ti, struct bio *bio, static void origin_resume(struct dm_target *ti) { struct dm_dev *dev = ti->private; - struct dm_snapshot *snap; - struct origin *o; - unsigned chunk_size = 0; down_read(&_origins_lock); - o = __lookup_origin(dev->bdev); - if (o) - list_for_each_entry (snap, &o->snapshots, list) - chunk_size = min_not_zero(chunk_size, - snap->store->chunk_size); - up_read(&_origins_lock); - ti->split_io = chunk_size; + ti->split_io = __minimum_chunk_size(__lookup_origin(dev->bdev)); + + up_read(&_origins_lock); } static int origin_status(struct dm_target *ti, status_type_t type, char *result, |