dm: fix opening log and cow devices for read only tables

If a table is read-only, also open any log and cow devices it uses read-only.

Previously, even read-only devices were opened read-write internally.
After patch 75f1dc0d076d1c1168f2115f1941ea627d38bd5a
  block: check bdev_read_only() from blkdev_get()
was applied, loading such tables began to fail.  The patch
was reverted by e51900f7d38cbcfb481d84567fd92540e7e1d23a
  block: revert block_dev read-only check
but this patch fixes this part of the code to work with the original patch.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 6951536..8e8a868 100644 (file)
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -543,7 +543,7 @@ static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
                return -EINVAL;
        }
 
-       r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &dev);
+       r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
        if (r)
                return r;
 

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index fdde53c..a2d3309 100644 (file)
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1080,7 +1080,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
        argv++;
        argc--;
 
-       r = dm_get_device(ti, cow_path, FMODE_READ | FMODE_WRITE, &s->cow);
+       r = dm_get_device(ti, cow_path, dm_table_get_mode(ti->table), &s->cow);
        if (r) {
                ti->error = "Cannot get COW device";
                goto bad_cow;