NFSv4: Implement the fs_locations function call

NFSv4 allows for the fact that filesystems may be replicated across
several servers or that they may be migrated to a backup server in case of
failure of the primary server.
fs_locations is an NFSv4 operation for retrieving information about the
location of migrated and/or replicated filesystems.

Based on an initial implementation by Jiaying Zhang <jiayingz@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 308407205e6c..768514dc0c4c 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3570,6 +3570,35 @@ ssize_t nfs4_listxattr(struct dentry *dentry, char *buf, size_t buflen)
         return len;
 }
 
+int nfs4_proc_fs_locations(struct inode *dir, struct dentry *dentry,
+                struct nfs_fs_locations *fs_locations, struct page *page)
+{
+        struct nfs_server *server = NFS_SERVER(dir);
+        u32 bitmask[2] = {
+                [0] = server->attr_bitmask[0] | FATTR4_WORD0_FS_LOCATIONS,
+                [1] = server->attr_bitmask[1],
+        };
+        struct nfs4_fs_locations_arg args = {
+                .dir_fh = NFS_FH(dir),
+                .name = &dentry->d_name,
+                .page = page,
+                .bitmask = bitmask,
+        };
+        struct rpc_message msg = {
+                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_FS_LOCATIONS],
+                .rpc_argp = &args,
+                .rpc_resp = &fs_locations,
+        };
+        int status;
+
+        dprintk("%s: start\n", __FUNCTION__);
+        fs_locations->fattr.valid = 0;
+        fs_locations->server = server;
+        status = rpc_call_sync(server->client, &msg, 0);
+        dprintk("%s: returned status = %d\n", __FUNCTION__, status);
+        return status;
+}
+
 struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops = {
         .recover_open   = nfs4_open_reclaim,
         .recover_lock   = nfs4_lock_reclaim,