- Add mount-epoch checking in most (all?) inode-using operations, in preparation

[fs/lustre-release.git] / lustre / llite / symlink.c

diff --git a/lustre/llite/symlink.c b/lustre/llite/symlink.c
index 83c41f4..d65220b 100644 (file)
--- a/lustre/llite/symlink.c
+++ b/lustre/llite/symlink.c
@@ -1,52 +1,115 @@
-/*
- *  linux/fs/ext2/symlink.c
+/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
+ * vim:expandtab:shiftwidth=8:tabstop=8:
  *
- * This code is issued under the GNU General Public License.
- * See the file COPYING in this distribution
+ *  Copyright (c) 2002 Cluster File Systems, Inc.
  *
- * Copyright (C) 1992, 1993, 1994, 1995
- * Remy Card (card@masi.ibp.fr)
- * Laboratoire MASI - Institut Blaise Pascal
- * Universite Pierre et Marie Curie (Paris VI)
+ *   This file is part of Lustre, http://www.lustre.org.
  *
- *  from
+ *   Lustre is free software; you can redistribute it and/or
+ *   modify it under the terms of version 2 of the GNU General Public
+ *   License as published by the Free Software Foundation.
  *
- *  linux/fs/minix/symlink.c
+ *   Lustre is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
  *
- *  Copyright (C) 1991, 1992  Linus Torvalds
- *
- *  ext2 symlink handling code
- *
- * Modified for OBDFS: 
- *  Copyright (C) 1999 Seagate Technology Inc. (author: braam@stelias.com)
+ *   You should have received a copy of the GNU General Public License
+ *   along with Lustre; if not, write to the Free Software
+ *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include <linux/fs.h>
-#include <linux/mm.h>
-#include <linux/stat.h>
-#include <linux/locks.h>
+#define DEBUG_SUBSYSTEM S_LLITE
+
+#include <linux/lustre_lite.h>
+
+static int ll_readlink_internal(struct inode *inode,
+                                struct ptlrpc_request **request, char **symname)
+{
+        struct ll_inode_info *lli = ll_i2info(inode);
+        struct ll_sb_info *sbi = ll_i2sbi(inode);
+        int rc, len = inode->i_size + 1;
+        ENTRY;
+
+        *request = NULL;
+
+        CHECK_MOUNT_EPOCH(inode);
+
+        if (lli->lli_symlink_name) {
+                *symname = lli->lli_symlink_name;
+                CDEBUG(D_INODE, "using cached symlink %s\n", *symname);
+                RETURN(0);
+        }
+
+        rc = mdc_getattr(&sbi->ll_mdc_conn, inode->i_ino, S_IFLNK,
+                         OBD_MD_LINKNAME, len, request);
+        if (rc) {
+                CERROR("inode "LPD64": rc = %d\n", inode->i_ino, rc);
+                RETURN(rc);
+        }
+
+        *symname = lustre_msg_buf((*request)->rq_repmsg, 1);
 
-#define DEBUG_SUBSYSTEM S_LLIGHT
+        OBD_ALLOC(lli->lli_symlink_name, len);
+        /* do not return an error if we cannot cache the symlink locally */
+        if (lli->lli_symlink_name)
+                memcpy(lli->lli_symlink_name, *symname, len);
 
-#include <linux/obd_support.h> /* for ENTRY and EXIT only */
-#include <linux/lustre_light.h>
+        RETURN(0);
+}
 
-static int ll_fast_readlink(struct dentry *dentry, char *buffer, int buflen)
+static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
 {
-        char *s = ll_i2info(dentry->d_inode)->lli_inline;
-        return vfs_readlink(dentry, buffer, buflen, s);
+        struct inode *inode = dentry->d_inode;
+        struct ll_inode_info *lli = ll_i2info(inode);
+        struct ptlrpc_request *request;
+        char *symname;
+        int rc;
+        ENTRY;
+
+        CHECK_MOUNT_EPOCH(inode);
+
+        /* on symlinks lli_open_sem protects lli_symlink_name allocation/data */
+        down(&lli->lli_open_sem);
+        rc = ll_readlink_internal(inode, &request, &symname);
+        if (rc)
+                GOTO(out, rc);
+
+        rc = vfs_readlink(dentry, buffer, buflen, symname);
+ out:
+        up(&lli->lli_open_sem);
+        ptlrpc_free_req(request);
+
+        RETURN(rc);
 }
 
-static int ll_fast_follow_link(struct dentry *dentry, struct nameidata *nd)
+static int ll_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
-        char *s = ll_i2info(dentry->d_inode)->lli_inline;
-        return vfs_follow_link(nd, s); 
+        struct inode *inode = dentry->d_inode;
+        struct ll_inode_info *lli = ll_i2info(inode);
+        struct ptlrpc_request *request;
+        char *symname;
+        int rc;
+        ENTRY;
+
+        CHECK_MOUNT_EPOCH(inode);
+
+        down(&lli->lli_open_sem);
+        rc = ll_readlink_internal(inode, &request, &symname);
+        if (rc)
+                GOTO(out, rc);
+
+       rc = vfs_follow_link(nd, symname);
+ out:
+        up(&lli->lli_open_sem);
+        ptlrpc_free_req(request);
+
+        RETURN(rc);
 }
 
 extern int ll_setattr(struct dentry *de, struct iattr *attr);
 struct inode_operations ll_fast_symlink_inode_operations = {
-        readlink:       ll_fast_readlink,
-        follow_link:    ll_fast_follow_link,
-       setattr:        ll_setattr
+        readlink:       ll_readlink,
+        setattr:        ll_setattr,
+        follow_link:    ll_follow_link
 };
-