From: Hannes Reinecke <hare@suse.de>
Subject: dm multipath devices are not getting created for readonly devices
References: bnc#382705
Patch-mainline: not yet, <hare: will revisit, Oct 4, 2017>
Currently we cannot create device-mapper tables for multipath devices
whenever they are read-only.
This patch modifies the device-mapper to set the 'READ-ONLY' flag
automatically whenever a read-only is added to the table.
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/md/dm-table.c | 3 +++
drivers/md/dm.c | 25 ++++++++++++++++++++++---
2 files changed, 25 insertions(+), 3 deletions(-)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -378,6 +378,9 @@ int dm_get_device(struct dm_target *ti,
return r;
}
+ if (dd->dm_dev->mode != mode)
+ t->mode = dd->dm_dev->mode;
+
refcount_set(&dd->count, 1);
list_add(&dd->list, &t->devices);
goto out;
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -303,16 +303,25 @@ int dm_deleting_md(struct mapped_device
static int dm_blk_open(struct block_device *bdev, fmode_t mode)
{
struct mapped_device *md;
+ int retval = 0;
spin_lock(&_minor_lock);
md = bdev->bd_disk->private_data;
- if (!md)
+ if (!md) {
+ retval = -ENXIO;
goto out;
+ }
if (test_bit(DMF_FREEING, &md->flags) ||
dm_deleting_md(md)) {
md = NULL;
+ retval = -ENXIO;
+ goto out;
+ }
+ if (get_disk_ro(md->disk) && (mode & FMODE_WRITE)) {
+ md = NULL;
+ retval = -EROFS;
goto out;
}
@@ -321,7 +330,7 @@ static int dm_blk_open(struct block_devi
out:
spin_unlock(&_minor_lock);
- return md ? 0 : -ENXIO;
+ return retval;
}
static void dm_blk_close(struct gendisk *disk, fmode_t mode)
@@ -699,7 +708,12 @@ int dm_get_table_device(struct mapped_de
td->dm_dev.mode = mode;
td->dm_dev.bdev = NULL;
- if ((r = open_table_device(td, dev, md))) {
+ r = open_table_device(td, dev, md);
+ if (r == -EROFS) {
+ td->dm_dev.mode &= ~FMODE_WRITE;
+ r = open_table_device(td, dev, md);
+ }
+ if (r) {
mutex_unlock(&md->table_devices_lock);
kfree(td);
return r;
@@ -1960,6 +1974,11 @@ static struct dm_table *__bind(struct ma
goto out;
}
+ if (!(dm_table_get_mode(t) & FMODE_WRITE))
+ set_disk_ro(md->disk, 1);
+ else
+ set_disk_ro(md->disk, 0);
+
old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
rcu_assign_pointer(md->map, (void *)t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);