pnfs: add set-clear layoutdriver interface

To allow layout driver to issue getdevicelist at mount time, and clean up
at umount time.

[fixup non NFS_V4_1 set_pnfs_layoutdriver definition]
[pnfs: pass mntfh down the init_pnfs path]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Jim Rees <rees@umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 24 insertions, 7 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 19ea7d9c75e6..a9b18483cb24 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -904,7 +904,9 @@ error:
 /*
  * Load up the server record from information gained in an fsinfo record
  */
-static void nfs_server_set_fsinfo(struct nfs_server *server, struct nfs_fsinfo *fsinfo)
+static void nfs_server_set_fsinfo(struct nfs_server *server,
+                                  struct nfs_fh *mntfh,
+                                  struct nfs_fsinfo *fsinfo)
 {
         unsigned long max_rpc_payload;
 
@@ -934,7 +936,7 @@ static void nfs_server_set_fsinfo(struct nfs_server *server, struct nfs_fsinfo *
         if (server->wsize > NFS_MAX_FILE_IO_SIZE)
                 server->wsize = NFS_MAX_FILE_IO_SIZE;
         server->wpages = (server->wsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-        set_pnfs_layoutdriver(server, fsinfo->layouttype);
+        set_pnfs_layoutdriver(server, mntfh, fsinfo->layouttype);
 
         server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
 
@@ -980,7 +982,7 @@ static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, str
         if (error < 0)
                 goto out_error;
 
-        nfs_server_set_fsinfo(server, &fsinfo);
+        nfs_server_set_fsinfo(server, mntfh, &fsinfo);
 
         /* Get some general file system info */
         if (server->namelen == 0) {
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index a7e5f17f7776..3a47f7ce1e90 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -76,8 +76,11 @@ find_pnfs_driver(u32 id)
 void
 unset_pnfs_layoutdriver(struct nfs_server *nfss)
 {
-        if (nfss->pnfs_curr_ld)
+        if (nfss->pnfs_curr_ld) {
+                if (nfss->pnfs_curr_ld->clear_layoutdriver)
+                        nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
                 module_put(nfss->pnfs_curr_ld->owner);
+        }
         nfss->pnfs_curr_ld = NULL;
 }
 
@@ -88,7 +91,8 @@ unset_pnfs_layoutdriver(struct nfs_server *nfss)
  * @id layout type. Zero (illegal layout type) indicates pNFS not in use.
  */
 void
-set_pnfs_layoutdriver(struct nfs_server *server, u32 id)
+set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
+                      u32 id)
 {
         struct pnfs_layoutdriver_type *ld_type = NULL;
 
@@ -115,6 +119,13 @@ set_pnfs_layoutdriver(struct nfs_server *server, u32 id)
                 goto out_no_driver;
         }
         server->pnfs_curr_ld = ld_type;
+        if (ld_type->set_layoutdriver
+            && ld_type->set_layoutdriver(server, mntfh)) {
+                printk(KERN_ERR "%s: Error initializing pNFS layout driver %u.\n",
+                                __func__, id);
+                module_put(ld_type->owner);
+                goto out_no_driver;
+        }
 
         dprintk("%s: pNFS module for %u set\n", __func__, id);
         return;
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 7074394944a9..bddd8b997e18 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -80,6 +80,9 @@ struct pnfs_layoutdriver_type {
         struct module *owner;
         unsigned flags;
 
+        int (*set_layoutdriver) (struct nfs_server *, const struct nfs_fh *);
+        int (*clear_layoutdriver) (struct nfs_server *);
+
         struct pnfs_layout_hdr * (*alloc_layout_hdr) (struct inode *inode, gfp_t gfp_flags);
         void (*free_layout_hdr) (struct pnfs_layout_hdr *);
 
@@ -167,7 +170,7 @@ void put_lseg(struct pnfs_layout_segment *lseg);
 bool pnfs_pageio_init_read(struct nfs_pageio_descriptor *, struct inode *);
 bool pnfs_pageio_init_write(struct nfs_pageio_descriptor *, struct inode *, int);
 
-void set_pnfs_layoutdriver(struct nfs_server *, u32 id);
+void set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh *, u32);
 void unset_pnfs_layoutdriver(struct nfs_server *);
 void pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *, struct nfs_page *);
 int pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc);
@@ -374,7 +377,8 @@ pnfs_roc_drain(struct inode *ino, u32 *barrier)
         return false;
 }
 
-static inline void set_pnfs_layoutdriver(struct nfs_server *s, u32 id)
+static inline void set_pnfs_layoutdriver(struct nfs_server *s,
+                                         const struct nfs_fh *mntfh, u32 id);
 {
 }