Whamcloud - gitweb
LU-709 build: clean up quota_read, follow_link and RCU
[fs/lustre-release.git] / lustre / llite / symlink.c
index 365910f..67a3107 100644 (file)
@@ -1,6 +1,4 @@
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  * GPL HEADER END
  */
 /*
- * Copyright  2008 Sun Microsystems, Inc. All rights reserved
+ * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, Whamcloud, Inc.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -37,7 +37,6 @@
 #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
 
@@ -51,21 +50,32 @@ static int ll_readlink_internal(struct inode *inode,
         struct ll_sb_info *sbi = ll_i2sbi(inode);
         int rc, symlen = i_size_read(inode) + 1;
         struct mdt_body *body;
-        struct obd_capa *oc;
+        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);
-        }
-
-        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 (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);
@@ -99,15 +109,11 @@ 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);
 }
 
@@ -120,121 +126,70 @@ static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
         ENTRY;
 
         CDEBUG(D_VFSTRACE, "VFS Op\n");
-        /* on symlinks lli_open_sem protects lli_symlink_name allocation/data */
-        ll_inode_size_lock(inode, 0);
+
+       ll_inode_size_lock(inode);
         rc = ll_readlink_internal(inode, &request, &symname);
         if (rc)
                 GOTO(out, rc);
 
         rc = vfs_readlink(dentry, buffer, buflen, symname);
-        ptlrpc_req_finished(request);
  out:
-        ll_inode_size_unlock(inode, 0);
-        RETURN(rc);
+        ptlrpc_req_finished(request);
+       ll_inode_size_unlock(inode);
+       RETURN(rc);
 }
 
-#ifdef HAVE_COOKIE_FOLLOW_LINK
-# define LL_FOLLOW_LINK_RETURN_TYPE void *
-#else
-# define LL_FOLLOW_LINK_RETURN_TYPE int
-#endif
-
-static LL_FOLLOW_LINK_RETURN_TYPE ll_follow_link(struct dentry *dentry,
-                                                 struct nameidata *nd)
+static void *ll_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
-        struct inode *inode = dentry->d_inode;
-#ifdef HAVE_VFS_INTENT_PATCHES
-        struct lookup_intent *it = ll_nd2it(nd);
-#endif
-        struct ptlrpc_request *request;
-        int rc;
-        char *symname;
-        ENTRY;
-
-#ifdef HAVE_VFS_INTENT_PATCHES
-        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;
-        }
-#endif
+       struct inode *inode = dentry->d_inode;
+       struct ptlrpc_request *request = NULL;
+       int rc;
+       char *symname;
+       ENTRY;
 
         CDEBUG(D_VFSTRACE, "VFS Op\n");
-#if THREAD_SIZE < 8192
-        /*
-         *  We set the limits recursive symlink to 5
-         *  instead of default 8 when kernel has 4k stack
-         *  to prevent stack overflow.
-         */
-        if (current->link_count >= 5) {
+        /* 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;
-                GOTO(out_release, rc);
+        } 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);
         }
-#endif
-        ll_inode_size_lock(inode, 0);
-        rc = ll_readlink_internal(inode, &request, &symname);
-        ll_inode_size_unlock(inode, 0);
         if (rc) {
-#if THREAD_SIZE < 8192
-out_release:
-#endif
-                path_release(nd); /* Kernel assumes that ->follow_link()
+                cfs_path_put(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);
-        }
-        nd_set_link(nd, symname);
-        RETURN(0);
-#endif
-#endif
+       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);
 out:
-        ptlrpc_req_finished(request);
-#ifdef HAVE_COOKIE_FOLLOW_LINK
-        RETURN(ERR_PTR(rc));
-#else
-        RETURN(rc);
-#endif
+       ptlrpc_req_finished(request);
+       RETURN(ERR_PTR(rc));
 }
 
-#ifdef HAVE_COOKIE_FOLLOW_LINK
 static void ll_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
 {
-        ptlrpc_req_finished(cookie);
+       ptlrpc_req_finished(cookie);
 }
-#endif
 
 struct inode_operations ll_fast_symlink_inode_operations = {
-        .readlink       = ll_readlink,
-        .setattr        = ll_setattr,
-#ifdef HAVE_VFS_INTENT_PATCHES
-        .setattr_raw    = ll_setattr_raw,
-#endif
-        .follow_link    = ll_follow_link,
-#ifdef HAVE_COOKIE_FOLLOW_LINK
-        .put_link       = ll_put_link,
-#endif
-        .getattr        = ll_getattr,
-        .permission     = ll_inode_permission,
-        .setxattr       = ll_setxattr,
-        .getxattr       = ll_getxattr,
-        .listxattr      = ll_listxattr,
-        .removexattr    = ll_removexattr,
+       .readlink       = ll_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,
 };