[PATCH] add touch_atime() helper

Preparation for per-mountpoint noatime, nodiratime and later -
per-mountpoint r/o.  Depends on file_accessed() patch, should go after
it.

New helper - touch_atime(mnt, dentry).  It's a wrapper for
update_atime() and that's where all future per-mountpoint checks will
go.

fs/namei.c

@@ -412,7 +412,7 @@ static inline int do_follow_link(struct dentry *dentry, struct nameidata *nd)
 		goto loop;
 	current->link_count++;
 	current->total_link_count++;
-	update_atime(dentry->d_inode);
+	touch_atime(nd->mnt, dentry);
 	err = dentry->d_inode->i_op->follow_link(dentry, nd);
 	current->link_count--;
 	return err;
@@ -1368,7 +1368,7 @@ int open_namei(const char * pathname, int flag, int mode, struct nameidata *nd)
 	error = security_inode_follow_link(dentry, nd);
 	if (error)
 		goto exit_dput;
-	update_atime(dentry->d_inode);
+	touch_atime(nd->mnt, dentry);
 	error = dentry->d_inode->i_op->follow_link(dentry, nd);
 	dput(dentry);
 	if (error)

fs/nfsd/vfs.c

@@ -1143,7 +1143,7 @@ nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
 	if (!inode->i_op || !inode->i_op->readlink)
 		goto out;
 
-	update_atime(inode);
+	touch_atime(fhp->fh_export->ex_mnt, dentry);
 	/* N.B. Why does this call need a get_fs()??
 	 * Remove the set_fs and watch the fireworks:-) --okir
 	 */

fs/stat.c

@@ -272,7 +272,7 @@ asmlinkage long sys_readlink(const char __user * path, char __user * buf, int bu
 		if (inode->i_op && inode->i_op->readlink) {
 			error = security_inode_readlink(nd.dentry);
 			if (!error) {
-				update_atime(inode);
+				touch_atime(nd.mnt, nd.dentry);
 				error = inode->i_op->readlink(nd.dentry, buf, bufsiz);
 			}
 		}

include/linux/fs.h

@@ -914,9 +914,15 @@ static inline void mark_inode_dirty_sync(struct inode *inode)
 	__mark_inode_dirty(inode, I_DIRTY_SYNC);
 }
 
+static inline void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
+{
+	/* per-mountpoint checks will go here */
+	update_atime(dentry->d_inode);
+}
+
 static inline void file_accessed(struct file *file)
 {
-	update_atime(file->f_dentry->d_inode);
+	touch_atime(file->f_vfsmnt, file->f_dentry);
 }
 
 

net/unix/af_unix.c

@@ -691,7 +691,7 @@ static struct sock *unix_find_other(struct sockaddr_un *sunname, int len,
 			goto put_fail;
 
 		if (u->sk_type == type)
-			update_atime(nd.dentry->d_inode);
+			touch_atime(nd.mnt, nd.dentry);
 
 		path_release(&nd);
 
@@ -707,7 +707,7 @@ static struct sock *unix_find_other(struct sockaddr_un *sunname, int len,
 			struct dentry *dentry;
 			dentry = unix_sk(u)->dentry;
 			if (dentry)
-				update_atime(dentry->d_inode);
+				touch_atime(unix_sk(u)->mnt, dentry);
 		} else
 			goto fail;
 	}