NFSv4: Reduce stack footprint of nfs4_get_root()

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

1 files changed, 46 insertions, 30 deletions

diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index ada369a5647b..7428f7d6273b 100644
--- 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 */