b=20595

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

diff --git a/lustre/llite/symlink.c b/lustre/llite/symlink.c
index 033e712..7db4a19 100644 (file)
--- a/lustre/llite/symlink.c
+++ b/lustre/llite/symlink.c
@@ -1,22 +1,37 @@
 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
  * vim:expandtab:shiftwidth=8:tabstop=8:
  *
- *  Copyright (c) 2002 Cluster File Systems, Inc.
+ * GPL HEADER START
  *
- *   This file is part of Lustre, http://www.lustre.org.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
- *   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.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
  *
- *   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.
+ * This program 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 version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
  *
- *   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.
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright  2008 Sun Microsystems, Inc. All rights reserved
+ * Use is subject to license terms.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
  */
 
 #include <linux/fs.h>
@@ -63,7 +78,7 @@ static int ll_readlink_internal(struct inode *inode,
                 CERROR("OBD_MD_LINKNAME not set on reply\n");
                 GOTO(failed, rc = -EPROTO);
         }
-        
+
         LASSERT(symlen != 0);
         if (body->eadatasize != symlen) {
                 CERROR("inode %lu: symlink length %d not expected %d\n",
@@ -84,22 +99,17 @@ static int ll_readlink_internal(struct inode *inode,
         /* do not return an error if we cannot cache the symlink locally */
         if (lli->lli_symlink_name) {
                 memcpy(lli->lli_symlink_name, *symname, symlen);
-                ptlrpc_req_finished (*request);
-                *request = NULL;
                 *symname = lli->lli_symlink_name;
         }
-
         RETURN(0);
 
- failed:
-        ptlrpc_req_finished (*request);
+failed:
         RETURN (rc);
 }
 
 static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
 {
         struct inode *inode = dentry->d_inode;
-        struct ll_inode_info *lli = ll_i2info(inode);
         struct ptlrpc_request *request;
         char *symname;
         int rc;
@@ -107,15 +117,15 @@ static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
 
         CDEBUG(D_VFSTRACE, "VFS Op\n");
         /* on symlinks lli_open_sem protects lli_symlink_name allocation/data */
-        down(&lli->lli_size_sem);
+        ll_inode_size_lock(inode, 0);
         rc = ll_readlink_internal(inode, &request, &symname);
         if (rc)
                 GOTO(out, rc);
 
         rc = vfs_readlink(dentry, buffer, buflen, symname);
-        ptlrpc_req_finished(request);
  out:
-        up(&lli->lli_size_sem);
+        ptlrpc_req_finished(request);
+        ll_inode_size_unlock(inode, 0);
         RETURN(rc);
 }
 
@@ -129,11 +139,10 @@ static LL_FOLLOW_LINK_RETURN_TYPE ll_follow_link(struct dentry *dentry,
                                                  struct nameidata *nd)
 {
         struct inode *inode = dentry->d_inode;
-        struct ll_inode_info *lli = ll_i2info(inode);
 #ifdef HAVE_VFS_INTENT_PATCHES
         struct lookup_intent *it = ll_nd2it(nd);
 #endif
-        struct ptlrpc_request *request;
+        struct ptlrpc_request *request = NULL;
         int rc;
         char *symname;
         ENTRY;
@@ -150,9 +159,15 @@ static LL_FOLLOW_LINK_RETURN_TYPE ll_follow_link(struct dentry *dentry,
 #endif
 
         CDEBUG(D_VFSTRACE, "VFS Op\n");
-        down(&lli->lli_size_sem);
-        rc = ll_readlink_internal(inode, &request, &symname);
-        up(&lli->lli_size_sem);
+        /* Limit the recursive symlink depth to 5 instead of default
+         * 8 links when kernel has 4k stack to prevent stack overflow. */
+        if (THREAD_SIZE < 8192 && current->link_count >= 5) {
+                rc = -ELOOP;
+        } else {
+                ll_inode_size_lock(inode, 0);
+                rc = ll_readlink_internal(inode, &request, &symname);
+                ll_inode_size_unlock(inode, 0);
+        }
         if (rc) {
                 path_release(nd); /* Kernel assumes that ->follow_link()
                                      releases nameidata on error */
@@ -168,10 +183,10 @@ static LL_FOLLOW_LINK_RETURN_TYPE ll_follow_link(struct dentry *dentry,
            we delay request releasing until ll_put_link then. */
         RETURN(request);
 #else
-        if (request != NULL) {
+        if (lli->lli_symlink_name == NULL) {
                 /* falling back to recursive follow link if the request
                  * needs to be cleaned up still. */
-        rc = vfs_follow_link(nd, symname);
+                rc = vfs_follow_link(nd, symname);
                 GOTO(out, rc);
         }
         nd_set_link(nd, symname);