pnfs: Add LAYOUTGET to OPEN of an existing file

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index f568a1de5ec58ebdc55bb0b6b2411afdb1701108..a6fe8132e94414dbef751d7ce11bbc5160ab6834 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -921,9 +921,9 @@ pnfs_find_server(struct inode *inode, struct nfs_open_context *ctx)
 {
        struct nfs_server *server;
 
-       if (inode)
+       if (inode) {
                server = NFS_SERVER(inode);
-       else {
+       } else {
                struct dentry *parent_dir = dget_parent(ctx->dentry);
                server = NFS_SERVER(parent_dir->d_inode);
                dput(parent_dir);
@@ -1736,6 +1736,22 @@ static void pnfs_clear_first_layoutget(struct pnfs_layout_hdr *lo)
        wake_up_bit(bitlock, NFS_LAYOUT_FIRST_LAYOUTGET);
 }
 
+static void _add_to_server_list(struct pnfs_layout_hdr *lo,
+                               struct nfs_server *server)
+{
+       if (list_empty(&lo->plh_layouts)) {
+               struct nfs_client *clp = server->nfs_client;
+
+               /* The lo must be on the clp list if there is any
+                * chance of a CB_LAYOUTRECALL(FILE) coming in.
+                */
+               spin_lock(&clp->cl_lock);
+               if (list_empty(&lo->plh_layouts))
+                       list_add_tail(&lo->plh_layouts, &server->layouts);
+               spin_unlock(&clp->cl_lock);
+       }
+}
+
 /*
  * Layout segment is retreived from the server if not cached.
  * The appropriate layout segment is referenced and returned to the caller.
@@ -1886,15 +1902,7 @@ lookup_again:
        atomic_inc(&lo->plh_outstanding);
        spin_unlock(&ino->i_lock);
 
-       if (list_empty(&lo->plh_layouts)) {
-               /* The lo must be on the clp list if there is any
-                * chance of a CB_LAYOUTRECALL(FILE) coming in.
-                */
-               spin_lock(&clp->cl_lock);
-               if (list_empty(&lo->plh_layouts))
-                       list_add_tail(&lo->plh_layouts, &server->layouts);
-               spin_unlock(&clp->cl_lock);
-       }
+       _add_to_server_list(lo, server);
 
        pg_offset = arg.offset & ~PAGE_MASK;
        if (pg_offset) {
@@ -1993,12 +2001,62 @@ pnfs_sanity_check_layout_range(struct pnfs_layout_range *range)
        return true;
 }
 
+static struct pnfs_layout_hdr *
+_pnfs_grab_empty_layout(struct inode *ino, struct nfs_open_context *ctx)
+{
+       struct pnfs_layout_hdr *lo;
+
+       spin_lock(&ino->i_lock);
+       lo = pnfs_find_alloc_layout(ino, ctx, GFP_KERNEL);
+       if (!lo)
+               goto out_unlock;
+       if (!test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags))
+               goto out_unlock;
+       if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
+               goto out_unlock;
+       if (pnfs_layoutgets_blocked(lo))
+               goto out_unlock;
+       if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET, &lo->plh_flags))
+               goto out_unlock;
+       atomic_inc(&lo->plh_outstanding);
+       spin_unlock(&ino->i_lock);
+       _add_to_server_list(lo, NFS_SERVER(ino));
+       return lo;
+
+out_unlock:
+       spin_unlock(&ino->i_lock);
+       pnfs_put_layout_hdr(lo);
+       return NULL;
+}
+
 extern const nfs4_stateid current_stateid;
 
 static void _lgopen_prepare_attached(struct nfs4_opendata *data,
                                     struct nfs_open_context *ctx)
 {
-       /* STUB */
+       struct inode *ino = data->dentry->d_inode;
+       struct pnfs_layout_range rng = {
+               .iomode = (data->o_arg.fmode & FMODE_WRITE) ?
+                         IOMODE_RW: IOMODE_READ,
+               .offset = 0,
+               .length = NFS4_MAX_UINT64,
+       };
+       struct nfs4_layoutget *lgp;
+       struct pnfs_layout_hdr *lo;
+
+       lo = _pnfs_grab_empty_layout(ino, ctx);
+       if (!lo)
+               return;
+       lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid,
+                                            &rng, GFP_KERNEL);
+       if (!lgp) {
+               pnfs_clear_first_layoutget(lo);
+               pnfs_put_layout_hdr(lo);
+               return;
+       }
+       data->lgp = lgp;
+       data->o_arg.lg_args = &lgp->args;
+       data->o_res.lg_res = &lgp->res;
 }
 
 static void _lgopen_prepare_floating(struct nfs4_opendata *data,
@@ -2046,11 +2104,9 @@ void pnfs_parse_lgopen(struct inode *ino, struct nfs4_layoutget *lgp,
        if (!lgp || lgp->res.layoutp->len == 0)
                return;
        if (!lgp->args.inode) {
-               /* Need to grab lo */
-               spin_lock(&ino->i_lock);
-               lo = pnfs_find_alloc_layout(ino, ctx, GFP_KERNEL);
-               atomic_inc(&lo->plh_outstanding);
-               spin_unlock(&ino->i_lock);
+               lo = _pnfs_grab_empty_layout(ino, ctx);
+               if (!lo)
+                       return;
                lgp->args.inode = ino;
        } else
                lo = NFS_I(lgp->args.inode)->layout;