nfs{,4}_lookup_validate(): use stable parent inode passed by caller

we can't kill __nfs_lookup_revalidate() completely, but ->d_parent boilerplate
in it is gone

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 9910d9796f4c3adcc309f63fff20d270cebd3852..c28983ee75caaf67ca2990e120eb40335871f00a 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1732,8 +1732,8 @@ out:
  * cached dentry and do a new lookup.
  */
 static int
-nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
-                        unsigned int flags)
+nfs_do_lookup_revalidate(struct inode *dir, const struct qstr *name,
+                        struct dentry *dentry, unsigned int flags)
 {
        struct inode *inode;
        int error = 0;
@@ -1785,39 +1785,26 @@ out_bad:
 }
 
 static int
-__nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags,
-                       int (*reval)(struct inode *, struct dentry *, unsigned int))
+__nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
 {
-       struct dentry *parent;
-       struct inode *dir;
-       int ret;
-
        if (flags & LOOKUP_RCU) {
                if (dentry->d_fsdata == NFS_FSDATA_BLOCKED)
                        return -ECHILD;
-               parent = READ_ONCE(dentry->d_parent);
-               dir = d_inode_rcu(parent);
-               if (!dir)
-                       return -ECHILD;
-               ret = reval(dir, dentry, flags);
-               if (parent != READ_ONCE(dentry->d_parent))
-                       return -ECHILD;
        } else {
                /* Wait for unlink to complete - see unblock_revalidate() */
                wait_var_event(&dentry->d_fsdata,
                               smp_load_acquire(&dentry->d_fsdata)
                               != NFS_FSDATA_BLOCKED);
-               parent = dget_parent(dentry);
-               ret = reval(d_inode(parent), dentry, flags);
-               dput(parent);
        }
-       return ret;
+       return 0;
 }
 
 static int nfs_lookup_revalidate(struct inode *dir, const struct qstr *name,
                                 struct dentry *dentry, unsigned int flags)
 {
-       return __nfs_lookup_revalidate(dentry, flags, nfs_do_lookup_revalidate);
+       if (__nfs_lookup_revalidate(dentry, flags))
+               return -ECHILD;
+       return nfs_do_lookup_revalidate(dir, name, dentry, flags);
 }
 
 static void block_revalidate(struct dentry *dentry)
@@ -2216,11 +2203,14 @@ no_open:
 EXPORT_SYMBOL_GPL(nfs_atomic_open);
 
 static int
-nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
-                         unsigned int flags)
+nfs4_lookup_revalidate(struct inode *dir, const struct qstr *name,
+                      struct dentry *dentry, unsigned int flags)
 {
        struct inode *inode;
 
+       if (__nfs_lookup_revalidate(dentry, flags))
+               return -ECHILD;
+
        trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
 
        if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY))
@@ -2259,14 +2249,7 @@ reval_dentry:
        return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);
 
 full_reval:
-       return nfs_do_lookup_revalidate(dir, dentry, flags);
-}
-
-static int nfs4_lookup_revalidate(struct inode *dir, const struct qstr *name,
-                                 struct dentry *dentry, unsigned int flags)
-{
-       return __nfs_lookup_revalidate(dentry, flags,
-                       nfs4_do_lookup_revalidate);
+       return nfs_do_lookup_revalidate(dir, name, dentry, flags);
 }
 
 #endif /* CONFIG_NFSV4 */