[PATCH 1/2] pnfsd: make /proc/fs/nfsd/pnfs_dlm_device report dlm device list.

["J. Bruce Fields" <bfields@citi.umich.edu>]

From: Eric Anderle <eanderle@umich.edu>

The ability to read the current device list is useful for debugging.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
---
 fs/nfsd/nfs4pnfsdlm.c            |   25 +++++++++++++++++++++++++
 fs/nfsd/nfsctl.c                 |    4 +++-
 include/linux/nfsd/nfs4pnfsdlm.h |    2 ++
 3 files changed, 30 insertions(+), 1 deletions(-)

diff --git a/fs/nfsd/nfs4pnfsdlm.c b/fs/nfsd/nfs4pnfsdlm.c
index 0cc295c..0351d71 100644
--- a/fs/nfsd/nfs4pnfsdlm.c
+++ b/fs/nfsd/nfs4pnfsdlm.c
@@ -62,6 +62,31 @@ nfsd4_find_pnfs_dlm_device(char *disk_name)
 	return NULL;
 }
 
+ssize_t
+nfsd4_get_pnfs_dlm_device_list(char *buf, ssize_t buflen)
+{
+	char *pos = buf;
+	ssize_t size = 0;
+	struct dlm_device_entry *dlm_pdev;
+	int ret = -EINVAL;
+
+	spin_lock(&dlm_device_list_lock);
+	list_for_each_entry(dlm_pdev, &dlm_device_list, dlm_dev_list)
+	{
+		int advanced;
+		advanced = snprintf(pos, buflen - size, "%s:%s\n", dlm_pdev->disk_name, dlm_pdev->ds_list);
+		if (advanced >= buflen - size)
+			goto out;
+		size += advanced;
+		pos += advanced;
+	}
+	ret = size;
+
+out:
+	spin_unlock(&dlm_device_list_lock);
+	return ret;
+}
+
 /*
  * pnfs_dlm_device string format:
  *     block-device-path:<ds1 ipv4 address>,<ds2 ipv4 address>
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 51b0ae1..034d96f 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1352,7 +1352,9 @@ static ssize_t __write_pnfs_dlm_device(struct file *file, char *buf,
 			return ret;
 
 		ret = nfsd4_set_pnfs_dlm_device(pnfs_dlm_device, len);
-	}
+	} else
+		return nfsd4_get_pnfs_dlm_device_list(buf, SIMPLE_TRANSACTION_LIMIT);
+
 	return ret <= 0 ? ret : strlen(buf);
 }
 
diff --git a/include/linux/nfsd/nfs4pnfsdlm.h b/include/linux/nfsd/nfs4pnfsdlm.h
index a961c1e..eb31123 100644
--- a/include/linux/nfsd/nfs4pnfsdlm.h
+++ b/include/linux/nfsd/nfs4pnfsdlm.h
@@ -42,6 +42,8 @@ int nfsd4_set_pnfs_dlm_device(char *pnfs_dlm_device, int len);
 
 void nfsd4_pnfs_dlm_shutdown(void);
 
+ssize_t nfsd4_get_pnfs_dlm_device_list(char *buf, ssize_t buflen);
+
 #else /* CONFIG_PNFSD */
 
 static inline void nfsd4_pnfs_dlm_shutdown(void)
-- 
1.7.0.4