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LU-4423 llite: remove ll_readlink as unnecessary
[fs/lustre-release.git] / lustre / llite / symlink.c
index f913d8a..e394efa 100644 (file)
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
+/*
+ * GPL HEADER START
  *
- *  Copyright (c) 2002 Cluster File Systems, Inc.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
- *   This file is part of Lustre, http://www.lustre.org.
+ * 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 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 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).
  *
- *   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.
+ * 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
  *
- *   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.
+ * 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 (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
  */
 
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/stat.h>
-#include <linux/smp_lock.h>
 #include <linux/version.h>
 #define DEBUG_SUBSYSTEM S_LLITE
 
-#include <linux/lustre_lite.h>
+#include <lustre_lite.h>
 #include "llite_internal.h"
 
 static int ll_readlink_internal(struct inode *inode,
-                                struct ptlrpc_request **request,
-                                char **symname)
+                                struct ptlrpc_request **request, char **symname)
 {
         struct ll_inode_info *lli = ll_i2info(inode);
         struct ll_sb_info *sbi = ll_i2sbi(inode);
-        struct lustre_id id;
-        struct mds_body *body;
-        int rc, symlen = inode->i_size + 1;
+        int rc, symlen = i_size_read(inode) + 1;
+        struct mdt_body *body;
+        struct md_op_data *op_data;
         ENTRY;
 
         *request = NULL;
 
-        if (lli->lli_symlink_name) {
-                *symname = lli->lli_symlink_name;
-                CDEBUG(D_INODE, "using cached symlink %s\n", *symname);
-                RETURN(0);
-        }
-
-        ll_inode2id(&id, inode);
-        rc = md_getattr(sbi->ll_md_exp, &id, OBD_MD_LINKNAME, symlen,
-                        request);
+       if (lli->lli_symlink_name) {
+               int print_limit = min_t(int, PAGE_SIZE - 128, symlen);
+
+               *symname = lli->lli_symlink_name;
+               /* If the total CDEBUG() size is larger than a page, it
+                * will print a warning to the console, avoid this by
+                * printing just the last part of the symlink. */
+               CDEBUG(D_INODE, "using cached symlink %s%.*s, len = %d\n",
+                      print_limit < symlen ? "..." : "", print_limit,
+                      (*symname) + symlen - print_limit, symlen);
+               RETURN(0);
+       }
+
+        op_data = ll_prep_md_op_data(NULL, inode, NULL, NULL, 0, symlen,
+                                     LUSTRE_OPC_ANY, NULL);
+        if (IS_ERR(op_data))
+                RETURN(PTR_ERR(op_data));
+
+        op_data->op_valid = OBD_MD_LINKNAME;
+        rc = md_getattr(sbi->ll_md_exp, op_data, request);
+        ll_finish_md_op_data(op_data);
         if (rc) {
                 if (rc != -ENOENT)
-                        CERROR("inode %lu: rc = %d\n", inode->i_ino, rc);
-                RETURN(rc);
+                       CERROR("%s: inode "DFID": rc = %d\n",
+                              ll_get_fsname(inode->i_sb, NULL, 0),
+                              PFID(ll_inode2fid(inode)), rc);
+                GOTO (failed, rc);
         }
 
-        body = lustre_msg_buf ((*request)->rq_repmsg, 0, sizeof (*body));
-        LASSERT (body != NULL);
-        LASSERT_REPSWABBED (*request, 0);
-
-        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);
+        body = req_capsule_server_get(&(*request)->rq_pill, &RMF_MDT_BODY);
+        LASSERT(body != NULL);
+       if ((body->mbo_valid & OBD_MD_LINKNAME) == 0) {
+               CERROR("OBD_MD_LINKNAME not set on reply\n");
+               GOTO(failed, rc = -EPROTO);
+       }
+
+       LASSERT(symlen != 0);
+       if (body->mbo_eadatasize != symlen) {
+               CERROR("%s: inode "DFID": symlink length %d not expected %d\n",
+                      ll_get_fsname(inode->i_sb, NULL, 0),
+                      PFID(ll_inode2fid(inode)), body->mbo_eadatasize - 1,
+                      symlen - 1);
+                GOTO(failed, rc = -EPROTO);
         }
 
-        *symname = lustre_msg_buf ((*request)->rq_repmsg, 1, symlen);
+        *symname = req_capsule_server_get(&(*request)->rq_pill, &RMF_MDT_MD);
         if (*symname == NULL ||
-            strnlen (*symname, symlen) != symlen - 1) {
+            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);
+               CERROR("%s: inode "DFID": symlink not NULL terminated string"
+                      "of length %d\n", ll_get_fsname(inode->i_sb, NULL, 0),
+                      PFID(ll_inode2fid(inode)), 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)
+        if (lli->lli_symlink_name) {
                 memcpy(lli->lli_symlink_name, *symname, symlen);
-
+                *symname = lli->lli_symlink_name;
+        }
         RETURN(0);
 
- failed:
-        ptlrpc_req_finished (*request);
-        RETURN (-EPROTO);
+failed:
+        RETURN (rc);
 }
 
-static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
+static void *ll_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
-        struct inode *inode = dentry->d_inode;
-        struct ll_inode_info *lli = ll_i2info(inode);
-        struct ptlrpc_request *request;
-        char *symname;
-        int rc;
-        ENTRY;
+       struct inode *inode = dentry->d_inode;
+       struct ptlrpc_request *request = NULL;
+       int rc;
+       char *symname = NULL;
+       ENTRY;
 
         CDEBUG(D_VFSTRACE, "VFS Op\n");
-        /* 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);
-        ptlrpc_req_finished(request);
- out:
-        up(&lli->lli_open_sem);
-        RETURN(rc);
+        /* Limit the recursive symlink depth to 5 instead of default
+         * 8 links when kernel has 4k stack to prevent stack overflow.
+         * For 8k stacks we need to limit it to 7 for local servers. */
+        if (THREAD_SIZE < 8192 && current->link_count >= 6) {
+                rc = -ELOOP;
+        } else if (THREAD_SIZE == 8192 && current->link_count >= 8) {
+                rc = -ELOOP;
+        } else {
+               ll_inode_size_lock(inode);
+               rc = ll_readlink_internal(inode, &request, &symname);
+               ll_inode_size_unlock(inode);
+        }
+       if (rc) {
+               ptlrpc_req_finished(request);
+               request = NULL;
+               symname = ERR_PTR(rc);
+       }
+
+       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);
 }
 
-static int ll_follow_link(struct dentry *dentry, struct nameidata *nd)
+static void ll_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
 {
-        struct inode *inode = dentry->d_inode;
-        struct ll_inode_info *lli = ll_i2info(inode);
-        struct lookup_intent *it = ll_nd2it(nd);
-        struct ptlrpc_request *request;
-        int rc;
-        char *symname;
-        ENTRY;
-
-        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;
-        }
-
-        CDEBUG(D_VFSTRACE, "VFS Op\n");
-        down(&lli->lli_open_sem);
-        rc = ll_readlink_internal(inode, &request, &symname);
-        up(&lli->lli_open_sem);
-        if (rc)
-                GOTO(out, rc);
-
-        rc = vfs_follow_link(nd, symname);
-        ptlrpc_req_finished(request);
- out:
-        RETURN(rc);
+       ptlrpc_req_finished(cookie);
 }
 
 struct inode_operations ll_fast_symlink_inode_operations = {
-        .readlink       = ll_readlink,
-        .setattr        = ll_setattr,
-        .setattr_raw    = ll_setattr_raw,
-        .follow_link    = ll_follow_link,
-#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
-        .revalidate_it  = ll_inode_revalidate_it
-#else 
-        .getattr_it     = ll_getattr
-#endif
+       .readlink       = generic_readlink,
+       .setattr        = ll_setattr,
+       .follow_link    = ll_follow_link,
+       .put_link       = ll_put_link,
+       .getattr        = ll_getattr,
+       .permission     = ll_inode_permission,
+       .setxattr       = ll_setxattr,
+       .getxattr       = ll_getxattr,
+       .listxattr      = ll_listxattr,
+       .removexattr    = ll_removexattr,
 };