drivers/staging/lustre/lustre/llite/dcache.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2015, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  */
  32
  33 #include <linux/fs.h>
  34 #include <linux/sched.h>
  35 #include <linux/quotaops.h>
  36
  37 #define DEBUG_SUBSYSTEM S_LLITE
  38
  39 #include "../include/obd_support.h"
  40 #include "../include/lustre/lustre_idl.h"
  41 #include "../include/lustre_dlm.h"
  42
  43 #include "llite_internal.h"
  44
  45 static void free_dentry_data(struct rcu_head *head)
  46 {
  47         struct ll_dentry_data *lld;
  48
  49         lld = container_of(head, struct ll_dentry_data, lld_rcu_head);
  50         kfree(lld);
  51 }
  52
  53 /* should NOT be called with the dcache lock, see fs/dcache.c */
  54 static void ll_release(struct dentry *de)
  55 {
  56         struct ll_dentry_data *lld;
  57
  58         LASSERT(de);
  59         lld = ll_d2d(de);
  60         if (lld->lld_it) {
  61                 ll_intent_release(lld->lld_it);
  62                 kfree(lld->lld_it);
  63         }
  64
  65         de->d_fsdata = NULL;
  66         call_rcu(&lld->lld_rcu_head, free_dentry_data);
  67 }
  68
  69 /* Compare if two dentries are the same.  Don't match if the existing dentry
  70  * is marked invalid.  Returns 1 if different, 0 if the same.
  71  *
  72  * This avoids a race where ll_lookup_it() instantiates a dentry, but we get
  73  * an AST before calling d_revalidate_it().  The dentry still exists (marked
  74  * INVALID) so d_lookup() matches it, but we have no lock on it (so
  75  * lock_match() fails) and we spin around real_lookup().
  76  */
  77 static int ll_dcompare(const struct dentry *dentry,
  78                        unsigned int len, const char *str,
  79                        const struct qstr *name)
  80 {
  81         if (len != name->len)
  82                 return 1;
  83
  84         if (memcmp(str, name->name, len))
  85                 return 1;
  86
  87         CDEBUG(D_DENTRY, "found name %.*s(%p) flags %#x refc %d\n",
  88                name->len, name->name, dentry, dentry->d_flags,
  89                d_count(dentry));
  90
  91         /* mountpoint is always valid */
  92         if (d_mountpoint((struct dentry *)dentry))
  93                 return 0;
  94
  95         if (d_lustre_invalid(dentry))
  96                 return 1;
  97
  98         return 0;
  99 }
 100
 101 /**
 102  * Called when last reference to a dentry is dropped and dcache wants to know
 103  * whether or not it should cache it:
 104  * - return 1 to delete the dentry immediately
 105  * - return 0 to cache the dentry
 106  * Should NOT be called with the dcache lock, see fs/dcache.c
 107  */
 108 static int ll_ddelete(const struct dentry *de)
 109 {
 110         LASSERT(de);
 111
 112         CDEBUG(D_DENTRY, "%s dentry %pd (%p, parent %p, inode %p) %s%s\n",
 113                d_lustre_invalid((struct dentry *)de) ? "deleting" : "keeping",
 114                de, de, de->d_parent, d_inode(de),
 115                d_unhashed(de) ? "" : "hashed,",
 116                list_empty(&de->d_subdirs) ? "" : "subdirs");
 117
 118         /* kernel >= 2.6.38 last refcount is decreased after this function. */
 119         LASSERT(d_count(de) == 1);
 120
 121         if (d_lustre_invalid((struct dentry *)de))
 122                 return 1;
 123         return 0;
 124 }
 125
 126 static int ll_d_init(struct dentry *de)
 127 {
 128         struct ll_dentry_data *lld = kzalloc(sizeof(*lld), GFP_KERNEL);
 129
 130         if (unlikely(!lld))
 131                 return -ENOMEM;
 132         lld->lld_invalid = 1;
 133         de->d_fsdata = lld;
 134         return 0;
 135 }
 136
 137 void ll_intent_drop_lock(struct lookup_intent *it)
 138 {
 139         if (it->it_op && it->it_lock_mode) {
 140                 struct lustre_handle handle;
 141
 142                 handle.cookie = it->it_lock_handle;
 143
 144                 CDEBUG(D_DLMTRACE, "releasing lock with cookie %#llx from it %p\n",
 145                        handle.cookie, it);
 146                 ldlm_lock_decref(&handle, it->it_lock_mode);
 147
 148                 /* bug 494: intent_release may be called multiple times, from
 149                  * this thread and we don't want to double-decref this lock
 150                  */
 151                 it->it_lock_mode = 0;
 152                 if (it->it_remote_lock_mode != 0) {
 153                         handle.cookie = it->it_remote_lock_handle;
 154
 155                         CDEBUG(D_DLMTRACE, "releasing remote lock with cookie%#llx from it %p\n",
 156                                handle.cookie, it);
 157                         ldlm_lock_decref(&handle,
 158                                          it->it_remote_lock_mode);
 159                         it->it_remote_lock_mode = 0;
 160                 }
 161         }
 162 }
 163
 164 void ll_intent_release(struct lookup_intent *it)
 165 {
 166         CDEBUG(D_INFO, "intent %p released\n", it);
 167         ll_intent_drop_lock(it);
 168         /* We are still holding extra reference on a request, need to free it */
 169         if (it_disposition(it, DISP_ENQ_OPEN_REF))
 170                 ptlrpc_req_finished(it->it_request); /* ll_file_open */
 171
 172         if (it_disposition(it, DISP_ENQ_CREATE_REF)) /* create rec */
 173                 ptlrpc_req_finished(it->it_request);
 174
 175         it->it_disposition = 0;
 176         it->it_request = NULL;
 177 }
 178
 179 void ll_invalidate_aliases(struct inode *inode)
 180 {
 181         struct dentry *dentry;
 182
 183         CDEBUG(D_INODE, "marking dentries for ino "DFID"(%p) invalid\n",
 184                PFID(ll_inode2fid(inode)), inode);
 185
 186         spin_lock(&inode->i_lock);
 187         hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 188                 CDEBUG(D_DENTRY, "dentry in drop %pd (%p) parent %p inode %p flags %d\n",
 189                        dentry, dentry, dentry->d_parent,
 190                        d_inode(dentry), dentry->d_flags);
 191
 192                 d_lustre_invalidate(dentry, 0);
 193         }
 194         spin_unlock(&inode->i_lock);
 195 }
 196
 197 int ll_revalidate_it_finish(struct ptlrpc_request *request,
 198                             struct lookup_intent *it,
 199                             struct inode *inode)
 200 {
 201         int rc = 0;
 202
 203         if (!request)
 204                 return 0;
 205
 206         if (it_disposition(it, DISP_LOOKUP_NEG))
 207                 return -ENOENT;
 208
 209         rc = ll_prep_inode(&inode, request, NULL, it);
 210
 211         return rc;
 212 }
 213
 214 void ll_lookup_finish_locks(struct lookup_intent *it, struct inode *inode)
 215 {
 216         if (it->it_lock_mode && inode) {
 217                 struct ll_sb_info *sbi = ll_i2sbi(inode);
 218
 219                 CDEBUG(D_DLMTRACE, "setting l_data to inode "DFID"(%p)\n",
 220                        PFID(ll_inode2fid(inode)), inode);
 221                 ll_set_lock_data(sbi->ll_md_exp, inode, it, NULL);
 222         }
 223
 224         /* drop lookup or getattr locks immediately */
 225         if (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR) {
 226                 /* on 2.6 there are situation when several lookups and
 227                  * revalidations may be requested during single operation.
 228                  * therefore, we don't release intent here -bzzz
 229                  */
 230                 ll_intent_drop_lock(it);
 231         }
 232 }
 233
 234 static int ll_revalidate_dentry(struct dentry *dentry,
 235                                 unsigned int lookup_flags)
 236 {
 237         struct inode *dir = d_inode(dentry->d_parent);
 238
 239         /* If this is intermediate component path lookup and we were able to get
 240          * to this dentry, then its lock has not been revoked and the
 241          * path component is valid.
 242          */
 243         if (lookup_flags & LOOKUP_PARENT)
 244                 return 1;
 245
 246         /* Symlink - always valid as long as the dentry was found */
 247         if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode))
 248                 return 1;
 249
 250         /*
 251          * VFS warns us that this is the second go around and previous
 252          * operation failed (most likely open|creat), so this time
 253          * we better talk to the server via the lookup path by name,
 254          * not by fid.
 255          */
 256         if (lookup_flags & LOOKUP_REVAL)
 257                 return 0;
 258
 259         if (!dentry_may_statahead(dir, dentry))
 260                 return 1;
 261
 262         if (lookup_flags & LOOKUP_RCU)
 263                 return -ECHILD;
 264
 265         ll_statahead(dir, &dentry, !d_inode(dentry));
 266         return 1;
 267 }
 268
 269 /*
 270  * Always trust cached dentries. Update statahead window if necessary.
 271  */
 272 static int ll_revalidate_nd(struct dentry *dentry, unsigned int flags)
 273 {
 274         CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, flags=%u\n",
 275                dentry, flags);
 276
 277         return ll_revalidate_dentry(dentry, flags);
 278 }
 279
 280 const struct dentry_operations ll_d_ops = {
 281         .d_init = ll_d_init,
 282         .d_revalidate = ll_revalidate_nd,
 283         .d_release = ll_release,
 284         .d_delete  = ll_ddelete,
 285         .d_compare = ll_dcompare,
 286 };