[Devel] [PATCH RH8 7/7] ploop: Add ignore_signature_disk_in_use parameter

[Kirill Tkhai]

Normally, userspace sets this parameter. But during development
it's usable to mount ploop directly (say, via bash script).
Introduce this parameter to ignore that signature is not set.

Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 drivers/md/dm-ploop-bat.c    |    2 +-
 drivers/md/dm-ploop-target.c |    5 +++++
 drivers/md/dm-ploop.h        |    1 +
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-ploop-bat.c b/drivers/md/dm-ploop-bat.c
index ee7150f5ae80..8226411c2dc8 100644
--- a/drivers/md/dm-ploop-bat.c
+++ b/drivers/md/dm-ploop-bat.c
@@ -255,7 +255,7 @@ int ploop_read_metadata(struct dm_target *ti, struct ploop *ploop)
 
 	ret = -ENOLCK;
 	if (m_hdr->m_DiskInUse != cpu_to_le32(SIGNATURE_DISK_IN_USE) &&
-	    !ploop_is_ro(ploop))
+	    !ploop_is_ro(ploop) && !ignore_signature_disk_in_use)
 		goto out;
 
 	ret = -EINVAL;
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 5581e2722e0b..37e581f2997f 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -13,6 +13,11 @@
 
 #define DM_MSG_PREFIX "ploop"
 
+bool ignore_signature_disk_in_use = false; /* For development purposes */
+module_param(ignore_signature_disk_in_use, bool, 0444);
+MODULE_PARM_DESC(ignore_signature_disk_in_use,
+                "Does not check for SIGNATURE_DISK_IN_USE");
+
 struct kmem_cache *piocb_cache;
 struct kmem_cache *cow_cache;
 
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index 1741a2075fb2..54baa1aa0229 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -274,6 +274,7 @@ struct ploop_cow {
 	void *data; /* Second argument of end_fn */
 };
 
+extern bool ignore_signature_disk_in_use;
 extern struct kmem_cache *piocb_cache;
 extern struct kmem_cache *cow_cache;