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-/*
- *  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>
-#include <linux/obd_support.h> /* for ENTRY and EXIT only */
-#include <linux/lustre_light.h>
+#include <linux/smp_lock.h>
+#include <linux/version.h>
+#define DEBUG_SUBSYSTEM S_LLITE
+
+#include <lustre_lite.h>
+#include "llite_internal.h"
 
-static int ll_fast_readlink(struct dentry *dentry, char *buffer, int buflen)
+static int ll_readlink_internal(struct inode *inode,
+                                struct ptlrpc_request **request, char **symname)
 {
-        char *s = ll_i2info(dentry->d_inode)->lli_inline;
-        return vfs_readlink(dentry, buffer, buflen, s);
+        struct ll_inode_info *lli = ll_i2info(inode);
+        struct ll_sb_info *sbi = ll_i2sbi(inode);
+        int rc, symlen = inode->i_size + 1;
+        struct mdt_body *body;
+        struct obd_capa *oc;
+        ENTRY;
+
+        *request = NULL;
+
+        if (lli->lli_symlink_name) {
+                *symname = lli->lli_symlink_name;
+                CDEBUG(D_INODE, "using cached symlink %s\n", *symname);
+                RETURN(0);
+        }
+
+        oc = ll_mdscapa_get(inode);
+        rc = md_getattr(sbi->ll_md_exp, ll_inode2fid(inode), oc,
+                        OBD_MD_LINKNAME, symlen, request);
+        capa_put(oc);
+        if (rc) {
+                if (rc != -ENOENT)
+                        CERROR("inode %lu: rc = %d\n", inode->i_ino, rc);
+                GOTO (failed, rc);
+        }
+
+        body = lustre_msg_buf((*request)->rq_repmsg, REPLY_REC_OFF,
+                              sizeof(*body));
+        LASSERT(body != NULL);
+        LASSERT_REPSWABBED(*request, REPLY_REC_OFF);
+
+        if ((body->valid & OBD_MD_LINKNAME) == 0) {
+                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",
+                        inode->i_ino, body->eadatasize - 1, symlen - 1);
+                GOTO(failed, rc = -EPROTO);
+        }
+
+        *symname = lustre_msg_buf((*request)->rq_repmsg, REPLY_REC_OFF + 1,
+                                  symlen);
+        if (*symname == NULL ||
+            strnlen (*symname, symlen) != symlen - 1) {
+                /* not full/NULL terminated */
+                CERROR("inode %lu: symlink not NULL terminated string"
+                        "of length %d\n", inode->i_ino, symlen - 1);
+                GOTO(failed, rc = -EPROTO);
+        }
+
+        OBD_ALLOC(lli->lli_symlink_name, symlen);
+        /* 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);
+        RETURN (rc);
 }
 
-static int ll_fast_follow_link(struct dentry *dentry, struct nameidata *nd)
+static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
 {
-        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;
+
+        CDEBUG(D_VFSTRACE, "VFS Op\n");
+        /* on symlinks lli_open_sem protects lli_symlink_name allocation/data */
+        down(&lli->lli_size_sem);
+        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);
+        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
-};
+#ifdef HAVE_COOKIE_FOLLOW_LINK
+# define LL_FOLLOW_LINK_RETURN_TYPE void *
+#else
+# define LL_FOLLOW_LINK_RETURN_TYPE int
+#endif
 
-static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
+static LL_FOLLOW_LINK_RETURN_TYPE ll_follow_link(struct dentry *dentry,
+                                                 struct nameidata *nd)
 {
-        struct page *page = NULL;
-        int res;
-
+        struct inode *inode = dentry->d_inode;
+        struct ll_inode_info *lli = ll_i2info(inode);
+#ifdef LUSTRE_KERNEL_VERSION
+        struct lookup_intent *it = ll_nd2it(nd);
+#endif
+        struct ptlrpc_request *request;
+        int rc;
+        char *symname;
         ENTRY;
-        OIDEBUG(dentry->d_inode);
-        page = ll_getpage(dentry->d_inode, 0, 0, 0);
-        /* PDEBUG(page, "readlink"); */
-        if (!page) {
-                EXIT;
-                return 0;
+
+#ifdef LUSTRE_KERNEL_VERSION
+        if (it != NULL) {
+                int op = it->it_op;
+                int mode = it->it_create_mode;
+
+                ll_intent_release(it);
+                it->it_op = op;
+                it->it_create_mode = mode;
         }
-        res = vfs_readlink(dentry, buffer, buflen, (char *)page_address(page));
-        page_cache_release(page);
-        EXIT;
-        return res;
-} /* ll_readlink */
-
-static int ll_follow_link(struct dentry * dentry,
-                             struct nameidata *nd)
-{
-        struct page *page = NULL;
-        int res;
+#endif
 
-        ENTRY;
-        OIDEBUG(dentry->d_inode);
-        page = ll_getpage(dentry->d_inode, 0, 0, 0);
-        /* PDEBUG(page, "follow_link"); */
-        if (!page) {
-                dput(nd->dentry);
-                EXIT;
-                return -EIO;
+        CDEBUG(D_VFSTRACE, "VFS Op\n");
+        down(&lli->lli_size_sem);
+        rc = ll_readlink_internal(inode, &request, &symname);
+        up(&lli->lli_size_sem);
+        if (rc) {
+                path_release(nd); /* Kernel assumes that ->follow_link()
+                                     releases nameidata on error */
+                GOTO(out, rc);
+        }
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,8))
+        rc = vfs_follow_link(nd, symname);
+#else
+#ifdef HAVE_COOKIE_FOLLOW_LINK
+        nd_set_link(nd, symname);
+        /* @symname may contain a pointer to the request message buffer,
+           we delay request releasing until ll_put_link then. */
+        RETURN(request);
+#else
+        if (request != NULL) {
+                /* falling back to recursive follow link if the request
+                 * needs to be cleaned up still. */
+        rc = vfs_follow_link(nd, symname);
+                GOTO(out, rc);
         }
-        res = vfs_follow_link(nd, (char *)page_address(page));
-        page_cache_release(page);
-        EXIT;
-        return res;
+        nd_set_link(nd, symname);
+        RETURN(0);
+#endif
+#endif
+out:
+        ptlrpc_req_finished(request);
+#ifdef HAVE_COOKIE_FOLLOW_LINK
+        RETURN(ERR_PTR(rc));
+#else
+        RETURN(rc);
+#endif
 }
 
-struct inode_operations ll_symlink_inode_operations = {
-        readlink:       ll_readlink,
-        follow_link:    ll_follow_link,
-       setattr:        ll_setattr
+#ifdef HAVE_COOKIE_FOLLOW_LINK
+static void ll_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
+{
+        ptlrpc_req_finished(cookie);
+}
+#endif
+
+struct inode_operations ll_fast_symlink_inode_operations = {
+        .readlink       = ll_readlink,
+        .setattr        = ll_setattr,
+#ifdef LUSTRE_KERNEL_VERSION
+        .setattr_raw    = ll_setattr_raw,
+#endif
+        .follow_link    = ll_follow_link,
+#ifdef HAVE_COOKIE_FOLLOW_LINK
+        .put_link       = ll_put_link,
+#endif
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
+        .revalidate_it  = ll_inode_revalidate_it,
+#else 
+        .getattr        = ll_getattr,
+#endif
+        .permission     = ll_inode_permission,
+        .setxattr       = ll_setxattr,
+        .getxattr       = ll_getxattr,
+        .listxattr      = ll_listxattr,
+        .removexattr    = ll_removexattr,
 };