NFSv4: Eliminate nfsv4 open race...

 Make NFSv4 return the fully initialized file pointer with the
 stateid that it created in the lookup w/intent.

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

1 files changed, 13 insertions, 16 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index c70eabd6d179..a6e251f21fd8 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -914,7 +914,6 @@ static int is_atomic_open(struct inode *dir, struct nameidata *nd)
 static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 {
         struct dentry *res = NULL;
-        struct inode *inode = NULL;
         int error;
 
         /* Check that we are indeed trying to open this file */
@@ -928,8 +927,10 @@ static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry
         dentry->d_op = NFS_PROTO(dir)->dentry_ops;
 
         /* Let vfs_create() deal with O_EXCL */
-        if (nd->intent.open.flags & O_EXCL)
-                goto no_entry;
+        if (nd->intent.open.flags & O_EXCL) {
+                d_add(dentry, NULL);
+                goto out;
+        }
 
         /* Open the file on the server */
         lock_kernel();
@@ -943,18 +944,18 @@ static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry
 
         if (nd->intent.open.flags & O_CREAT) {
                 nfs_begin_data_update(dir);
-                inode = nfs4_atomic_open(dir, dentry, nd);
+                res = nfs4_atomic_open(dir, dentry, nd);
                 nfs_end_data_update(dir);
         } else
-                inode = nfs4_atomic_open(dir, dentry, nd);
+                res = nfs4_atomic_open(dir, dentry, nd);
         unlock_kernel();
-        if (IS_ERR(inode)) {
-                error = PTR_ERR(inode);
+        if (IS_ERR(res)) {
+                error = PTR_ERR(res);
                 switch (error) {
                         /* Make a negative dentry */
                         case -ENOENT:
-                                inode = NULL;
-                                break;
+                                res = NULL;
+                                goto out;
                         /* This turned out not to be a regular file */
                         case -ELOOP:
                                 if (!(nd->intent.open.flags & O_NOFOLLOW))
@@ -962,13 +963,9 @@ static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry
                         /* case -EISDIR: */
                         /* case -EINVAL: */
                         default:
-                                res = ERR_PTR(error);
                                 goto out;
                 }
-        }
-no_entry:
-        res = d_add_unique(dentry, inode);
-        if (res != NULL)
+        } else if (res != NULL)
                 dentry = res;
         nfs_renew_times(dentry);
         nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
@@ -1012,7 +1009,7 @@ static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd)
          */
         lock_kernel();
         verifier = nfs_save_change_attribute(dir);
-        ret = nfs4_open_revalidate(dir, dentry, openflags);
+        ret = nfs4_open_revalidate(dir, dentry, openflags, nd);
         if (!ret)
                 nfs_set_verifier(dentry, verifier);
         unlock_kernel();
@@ -1135,7 +1132,7 @@ static int nfs_create(struct inode *dir, struct dentry *dentry, int mode,
 
         lock_kernel();
         nfs_begin_data_update(dir);
-        error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
+        error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd);
         nfs_end_data_update(dir);
         if (error != 0)
                 goto out_err;