NFSv4: Reduce stack footprint of nfs4_get_root()

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index ada369a..7428f7d 100644 (file)
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -78,46 +78,52 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
 {
        struct nfs_server *server = NFS_SB(sb);
        struct nfs_fsinfo fsinfo;
-       struct nfs_fattr fattr;
-       struct dentry *mntroot;
+       struct dentry *ret;
        struct inode *inode;
        int error;
 
        /* get the actual root for this mount */
-       fsinfo.fattr = &fattr;
+       fsinfo.fattr = nfs_alloc_fattr();
+       if (fsinfo.fattr == NULL)
+               return ERR_PTR(-ENOMEM);
 
        error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
        if (error < 0) {
                dprintk("nfs_get_root: getattr error = %d\n", -error);
-               return ERR_PTR(error);
+               ret = ERR_PTR(error);
+               goto out;
        }
 
        inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
        if (IS_ERR(inode)) {
                dprintk("nfs_get_root: get root inode failed\n");
-               return ERR_CAST(inode);
+               ret = ERR_CAST(inode);
+               goto out;
        }
 
        error = nfs_superblock_set_dummy_root(sb, inode);
-       if (error != 0)
-               return ERR_PTR(error);
+       if (error != 0) {
+               ret = ERR_PTR(error);
+               goto out;
+       }
 
        /* root dentries normally start off anonymous and get spliced in later
         * if the dentry tree reaches them; however if the dentry already
         * exists, we'll pick it up at this point and use it as the root
         */
-       mntroot = d_obtain_alias(inode);
-       if (IS_ERR(mntroot)) {
+       ret = d_obtain_alias(inode);
+       if (IS_ERR(ret)) {
                dprintk("nfs_get_root: get root dentry failed\n");
-               return mntroot;
+               goto out;
        }
 
-       security_d_instantiate(mntroot, inode);
+       security_d_instantiate(ret, inode);
 
-       if (!mntroot->d_op)
-               mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops;
-
-       return mntroot;
+       if (ret->d_op == NULL)
+               ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
+out:
+       nfs_free_fattr(fsinfo.fattr);
+       return ret;
 }
 
 #ifdef CONFIG_NFS_V4
@@ -168,8 +174,8 @@ out:
 struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
 {
        struct nfs_server *server = NFS_SB(sb);
-       struct nfs_fattr fattr;
-       struct dentry *mntroot;
+       struct nfs_fattr *fattr = NULL;
+       struct dentry *ret;
        struct inode *inode;
        int error;
 
@@ -183,40 +189,50 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
                return ERR_PTR(error);
        }
 
+       fattr = nfs_alloc_fattr();
+       if (fattr == NULL)
+               return ERR_PTR(-ENOMEM);;
+
        /* get the actual root for this mount */
-       error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr);
+       error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
        if (error < 0) {
                dprintk("nfs_get_root: getattr error = %d\n", -error);
-               return ERR_PTR(error);
+               ret = ERR_PTR(error);
+               goto out;
        }
 
-       inode = nfs_fhget(sb, mntfh, &fattr);
+       inode = nfs_fhget(sb, mntfh, fattr);
        if (IS_ERR(inode)) {
                dprintk("nfs_get_root: get root inode failed\n");
-               return ERR_CAST(inode);
+               ret = ERR_CAST(inode);
+               goto out;
        }
 
        error = nfs_superblock_set_dummy_root(sb, inode);
-       if (error != 0)
-               return ERR_PTR(error);
+       if (error != 0) {
+               ret = ERR_PTR(error);
+               goto out;
+       }
 
        /* root dentries normally start off anonymous and get spliced in later
         * if the dentry tree reaches them; however if the dentry already
         * exists, we'll pick it up at this point and use it as the root
         */
-       mntroot = d_obtain_alias(inode);
-       if (IS_ERR(mntroot)) {
+       ret = d_obtain_alias(inode);
+       if (IS_ERR(ret)) {
                dprintk("nfs_get_root: get root dentry failed\n");
-               return mntroot;
+               goto out;
        }
 
-       security_d_instantiate(mntroot, inode);
+       security_d_instantiate(ret, inode);
 
-       if (!mntroot->d_op)
-               mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops;
+       if (ret->d_op == NULL)
+               ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
 
+out:
+       nfs_free_fattr(fattr);
        dprintk("<-- nfs4_get_root()\n");
-       return mntroot;
+       return ret;
 }
 
 #endif /* CONFIG_NFS_V4 */