NFS: Reduce the stack footprint of nfs_lookup

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

2 files changed, 41 insertions, 14 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index a7bb5c694aa3..1debc09eb55f 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -776,9 +776,9 @@ static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)
         struct inode *dir;
         struct inode *inode;
         struct dentry *parent;
+        struct nfs_fh *fhandle = NULL;
+        struct nfs_fattr *fattr = NULL;
         int error;
-        struct nfs_fh fhandle;
-        struct nfs_fattr fattr;
 
         parent = dget_parent(dentry);
         dir = parent->d_inode;
@@ -811,14 +811,22 @@ static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)
         if (NFS_STALE(inode))
                 goto out_bad;
 
-        error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
+        error = -ENOMEM;
+        fhandle = nfs_alloc_fhandle();
+        fattr = nfs_alloc_fattr();
+        if (fhandle == NULL || fattr == NULL)
+                goto out_error;
+
+        error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
         if (error)
                 goto out_bad;
-        if (nfs_compare_fh(NFS_FH(inode), &fhandle))
+        if (nfs_compare_fh(NFS_FH(inode), fhandle))
                 goto out_bad;
-        if ((error = nfs_refresh_inode(inode, &fattr)) != 0)
+        if ((error = nfs_refresh_inode(inode, fattr)) != 0)
                 goto out_bad;
 
+        nfs_free_fattr(fattr);
+        nfs_free_fhandle(fhandle);
 out_set_verifier:
         nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
  out_valid:
@@ -842,11 +850,21 @@ out_zap_parent:
                 shrink_dcache_parent(dentry);
         }
         d_drop(dentry);
+        nfs_free_fattr(fattr);
+        nfs_free_fhandle(fhandle);
         dput(parent);
         dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n",
                         __func__, dentry->d_parent->d_name.name,
                         dentry->d_name.name);
         return 0;
+out_error:
+        nfs_free_fattr(fattr);
+        nfs_free_fhandle(fhandle);
+        dput(parent);
+        dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) lookup returned error %d\n",
+                        __func__, dentry->d_parent->d_name.name,
+                        dentry->d_name.name, error);
+        return error;
 }
 
 /*
@@ -911,9 +929,9 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
         struct dentry *res;
         struct dentry *parent;
         struct inode *inode = NULL;
+        struct nfs_fh *fhandle = NULL;
+        struct nfs_fattr *fattr = NULL;
         int error;
-        struct nfs_fh fhandle;
-        struct nfs_fattr fattr;
 
         dfprintk(VFS, "NFS: lookup(%s/%s)\n",
                 dentry->d_parent->d_name.name, dentry->d_name.name);
@@ -923,7 +941,6 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
         if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
                 goto out;
 
-        res = ERR_PTR(-ENOMEM);
         dentry->d_op = NFS_PROTO(dir)->dentry_ops;
 
         /*
@@ -936,17 +953,23 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
                 goto out;
         }
 
+        res = ERR_PTR(-ENOMEM);
+        fhandle = nfs_alloc_fhandle();
+        fattr = nfs_alloc_fattr();
+        if (fhandle == NULL || fattr == NULL)
+                goto out;
+
         parent = dentry->d_parent;
         /* Protect against concurrent sillydeletes */
         nfs_block_sillyrename(parent);
-        error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
+        error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
         if (error == -ENOENT)
                 goto no_entry;
         if (error < 0) {
                 res = ERR_PTR(error);
                 goto out_unblock_sillyrename;
         }
-        inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
+        inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
         res = (struct dentry *)inode;
         if (IS_ERR(res))
                 goto out_unblock_sillyrename;
@@ -962,6 +985,8 @@ no_entry:
 out_unblock_sillyrename:
         nfs_unblock_sillyrename(parent);
 out:
+        nfs_free_fattr(fattr);
+        nfs_free_fhandle(fhandle);
         return res;
 }
 
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index e701002694e5..72334c19d481 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -144,14 +144,12 @@ static int
 nfs3_proc_lookup(struct inode *dir, struct qstr *name,
                  struct nfs_fh *fhandle, struct nfs_fattr *fattr)
 {
-        struct nfs_fattr        dir_attr;
         struct nfs3_diropargs   arg = {
                 .fh             = NFS_FH(dir),
                 .name           = name->name,
                 .len            = name->len
         };
         struct nfs3_diropres    res = {
-                .dir_attr       = &dir_attr,
                 .fh             = fhandle,
                 .fattr          = fattr
         };
@@ -163,16 +161,20 @@ nfs3_proc_lookup(struct inode *dir, struct qstr *name,
         int                     status;
 
         dprintk("NFS call  lookup %s\n", name->name);
-        nfs_fattr_init(&dir_attr);
+        res.dir_attr = nfs_alloc_fattr();
+        if (res.dir_attr == NULL)
+                return -ENOMEM;
+
         nfs_fattr_init(fattr);
         status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
-        nfs_refresh_inode(dir, &dir_attr);
+        nfs_refresh_inode(dir, res.dir_attr);
         if (status >= 0 && !(fattr->valid & NFS_ATTR_FATTR)) {
                 msg.rpc_proc = &nfs3_procedures[NFS3PROC_GETATTR];
                 msg.rpc_argp = fhandle;
                 msg.rpc_resp = fattr;
                 status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
         }
+        nfs_free_fattr(res.dir_attr);
         dprintk("NFS reply lookup: %d\n", status);
         return status;
 }