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.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2015, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  */
  36
  37 #include <linux/fs.h>
  38 #include <linux/sched.h>
  39 #include <linux/quotaops.h>
  40
  41 #define DEBUG_SUBSYSTEM S_LLITE
  42
  43 #include "../include/obd_support.h"
  44 #include "../include/lustre_lite.h"
  45 #include "../include/lustre/lustre_idl.h"
  46 #include "../include/lustre_dlm.h"
  47
  48 #include "llite_internal.h"
  49
  50 static void free_dentry_data(struct rcu_head *head)
  51 {
  52         struct ll_dentry_data *lld;
  53
  54         lld = container_of(head, struct ll_dentry_data, lld_rcu_head);
  55         kfree(lld);
  56 }
  57
  58 /* should NOT be called with the dcache lock, see fs/dcache.c */
  59 static void ll_release(struct dentry *de)
  60 {
  61         struct ll_dentry_data *lld;
  62
  63         LASSERT(de != NULL);
  64         lld = ll_d2d(de);
  65         if (!lld) /* NFS copies the de->d_op methods (bug 4655) */
  66                 return;
  67
  68         if (lld->lld_it) {
  69                 ll_intent_release(lld->lld_it);
  70                 kfree(lld->lld_it);
  71         }
  72
  73         de->d_fsdata = NULL;
  74         call_rcu(&lld->lld_rcu_head, free_dentry_data);
  75 }
  76
  77 /* Compare if two dentries are the same.  Don't match if the existing dentry
  78  * is marked invalid.  Returns 1 if different, 0 if the same.
  79  *
  80  * This avoids a race where ll_lookup_it() instantiates a dentry, but we get
  81  * an AST before calling d_revalidate_it().  The dentry still exists (marked
  82  * INVALID) so d_lookup() matches it, but we have no lock on it (so
  83  * lock_match() fails) and we spin around real_lookup(). */
  84 static int ll_dcompare(const struct dentry *parent, const struct dentry *dentry,
  85                        unsigned int len, const char *str,
  86                        const struct qstr *name)
  87 {
  88         if (len != name->len)
  89                 return 1;
  90
  91         if (memcmp(str, name->name, len))
  92                 return 1;
  93
  94         CDEBUG(D_DENTRY, "found name %.*s(%p) flags %#x refc %d\n",
  95                name->len, name->name, dentry, dentry->d_flags,
  96                d_count(dentry));
  97
  98         /* mountpoint is always valid */
  99         if (d_mountpoint((struct dentry *)dentry))
 100                 return 0;
 101
 102         if (d_lustre_invalid(dentry))
 103                 return 1;
 104
 105         return 0;
 106 }
 107
 108 static inline int return_if_equal(struct ldlm_lock *lock, void *data)
 109 {
 110         if ((lock->l_flags &
 111              (LDLM_FL_CANCELING | LDLM_FL_DISCARD_DATA)) ==
 112             (LDLM_FL_CANCELING | LDLM_FL_DISCARD_DATA))
 113                 return LDLM_ITER_CONTINUE;
 114         return LDLM_ITER_STOP;
 115 }
 116
 117 /* find any ldlm lock of the inode in mdc and lov
 118  * return 0    not find
 119  *      1    find one
 120  *      < 0    error */
 121 static int find_cbdata(struct inode *inode)
 122 {
 123         struct ll_sb_info *sbi = ll_i2sbi(inode);
 124         struct lov_stripe_md *lsm;
 125         int rc = 0;
 126
 127         LASSERT(inode);
 128         rc = md_find_cbdata(sbi->ll_md_exp, ll_inode2fid(inode),
 129                             return_if_equal, NULL);
 130         if (rc != 0)
 131                 return rc;
 132
 133         lsm = ccc_inode_lsm_get(inode);
 134         if (!lsm)
 135                 return rc;
 136
 137         rc = obd_find_cbdata(sbi->ll_dt_exp, lsm, return_if_equal, NULL);
 138         ccc_inode_lsm_put(inode, lsm);
 139
 140         return rc;
 141 }
 142
 143 /**
 144  * Called when last reference to a dentry is dropped and dcache wants to know
 145  * whether or not it should cache it:
 146  * - return 1 to delete the dentry immediately
 147  * - return 0 to cache the dentry
 148  * Should NOT be called with the dcache lock, see fs/dcache.c
 149  */
 150 static int ll_ddelete(const struct dentry *de)
 151 {
 152         LASSERT(de);
 153
 154         CDEBUG(D_DENTRY, "%s dentry %pd (%p, parent %p, inode %p) %s%s\n",
 155                d_lustre_invalid((struct dentry *)de) ? "deleting" : "keeping",
 156                de, de, de->d_parent, d_inode(de),
 157                d_unhashed(de) ? "" : "hashed,",
 158                list_empty(&de->d_subdirs) ? "" : "subdirs");
 159
 160         /* kernel >= 2.6.38 last refcount is decreased after this function. */
 161         LASSERT(d_count(de) == 1);
 162
 163         /* Disable this piece of code temporarily because this is called
 164          * inside dcache_lock so it's not appropriate to do lots of work
 165          * here. ATTENTION: Before this piece of code enabling, LU-2487 must be
 166          * resolved. */
 167 #if 0
 168         /* if not ldlm lock for this inode, set i_nlink to 0 so that
 169          * this inode can be recycled later b=20433 */
 170         if (d_really_is_positive(de) && !find_cbdata(d_inode(de)))
 171                 clear_nlink(d_inode(de));
 172 #endif
 173
 174         if (d_lustre_invalid((struct dentry *)de))
 175                 return 1;
 176         return 0;
 177 }
 178
 179 int ll_d_init(struct dentry *de)
 180 {
 181         LASSERT(de != NULL);
 182
 183         CDEBUG(D_DENTRY, "ldd on dentry %pd (%p) parent %p inode %p refc %d\n",
 184                 de, de, de->d_parent, d_inode(de),
 185                 d_count(de));
 186
 187         if (!de->d_fsdata) {
 188                 struct ll_dentry_data *lld;
 189
 190                 lld = kzalloc(sizeof(*lld), GFP_NOFS);
 191                 if (likely(lld)) {
 192                         spin_lock(&de->d_lock);
 193                         if (likely(!de->d_fsdata)) {
 194                                 de->d_fsdata = lld;
 195                                 __d_lustre_invalidate(de);
 196                         } else {
 197                                 kfree(lld);
 198                         }
 199                         spin_unlock(&de->d_lock);
 200                 } else {
 201                         return -ENOMEM;
 202                 }
 203         }
 204         LASSERT(de->d_op == &ll_d_ops);
 205
 206         return 0;
 207 }
 208
 209 void ll_intent_drop_lock(struct lookup_intent *it)
 210 {
 211         if (it->it_op && it->d.lustre.it_lock_mode) {
 212                 struct lustre_handle handle;
 213
 214                 handle.cookie = it->d.lustre.it_lock_handle;
 215
 216                 CDEBUG(D_DLMTRACE, "releasing lock with cookie %#llx from it %p\n",
 217                        handle.cookie, it);
 218                 ldlm_lock_decref(&handle, it->d.lustre.it_lock_mode);
 219
 220                 /* bug 494: intent_release may be called multiple times, from
 221                  * this thread and we don't want to double-decref this lock */
 222                 it->d.lustre.it_lock_mode = 0;
 223                 if (it->d.lustre.it_remote_lock_mode != 0) {
 224                         handle.cookie = it->d.lustre.it_remote_lock_handle;
 225
 226                         CDEBUG(D_DLMTRACE, "releasing remote lock with cookie%#llx from it %p\n",
 227                                handle.cookie, it);
 228                         ldlm_lock_decref(&handle,
 229                                          it->d.lustre.it_remote_lock_mode);
 230                         it->d.lustre.it_remote_lock_mode = 0;
 231                 }
 232         }
 233 }
 234
 235 void ll_intent_release(struct lookup_intent *it)
 236 {
 237         CDEBUG(D_INFO, "intent %p released\n", it);
 238         ll_intent_drop_lock(it);
 239         /* We are still holding extra reference on a request, need to free it */
 240         if (it_disposition(it, DISP_ENQ_OPEN_REF))
 241                 ptlrpc_req_finished(it->d.lustre.it_data); /* ll_file_open */
 242
 243         if (it_disposition(it, DISP_ENQ_CREATE_REF)) /* create rec */
 244                 ptlrpc_req_finished(it->d.lustre.it_data);
 245
 246         it->d.lustre.it_disposition = 0;
 247         it->d.lustre.it_data = NULL;
 248 }
 249
 250 void ll_invalidate_aliases(struct inode *inode)
 251 {
 252         struct dentry *dentry;
 253
 254         LASSERT(inode != NULL);
 255
 256         CDEBUG(D_INODE, "marking dentries for ino %lu/%u(%p) invalid\n",
 257                inode->i_ino, inode->i_generation, inode);
 258
 259         ll_lock_dcache(inode);
 260         hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 261                 CDEBUG(D_DENTRY, "dentry in drop %pd (%p) parent %p inode %p flags %d\n",
 262                        dentry, dentry, dentry->d_parent,
 263                        d_inode(dentry), dentry->d_flags);
 264
 265                 d_lustre_invalidate(dentry, 0);
 266         }
 267         ll_unlock_dcache(inode);
 268 }
 269
 270 int ll_revalidate_it_finish(struct ptlrpc_request *request,
 271                             struct lookup_intent *it,
 272                             struct inode *inode)
 273 {
 274         int rc = 0;
 275
 276         if (!request)
 277                 return 0;
 278
 279         if (it_disposition(it, DISP_LOOKUP_NEG))
 280                 return -ENOENT;
 281
 282         rc = ll_prep_inode(&inode, request, NULL, it);
 283
 284         return rc;
 285 }
 286
 287 void ll_lookup_finish_locks(struct lookup_intent *it, struct inode *inode)
 288 {
 289         LASSERT(it != NULL);
 290
 291         if (it->d.lustre.it_lock_mode && inode != NULL) {
 292                 struct ll_sb_info *sbi = ll_i2sbi(inode);
 293
 294                 CDEBUG(D_DLMTRACE, "setting l_data to inode %p (%lu/%u)\n",
 295                        inode, inode->i_ino, inode->i_generation);
 296                 ll_set_lock_data(sbi->ll_md_exp, inode, it, NULL);
 297         }
 298
 299         /* drop lookup or getattr locks immediately */
 300         if (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR) {
 301                 /* on 2.6 there are situation when several lookups and
 302                  * revalidations may be requested during single operation.
 303                  * therefore, we don't release intent here -bzzz */
 304                 ll_intent_drop_lock(it);
 305         }
 306 }
 307
 308 static int ll_revalidate_dentry(struct dentry *dentry,
 309                                 unsigned int lookup_flags)
 310 {
 311         struct inode *dir = d_inode(dentry->d_parent);
 312
 313         /*
 314          * if open&create is set, talk to MDS to make sure file is created if
 315          * necessary, because we can't do this in ->open() later since that's
 316          * called on an inode. return 0 here to let lookup to handle this.
 317          */
 318         if ((lookup_flags & (LOOKUP_OPEN | LOOKUP_CREATE)) ==
 319             (LOOKUP_OPEN | LOOKUP_CREATE))
 320                 return 0;
 321
 322         if (lookup_flags & (LOOKUP_PARENT | LOOKUP_OPEN | LOOKUP_CREATE))
 323                 return 1;
 324
 325         if (d_need_statahead(dir, dentry) <= 0)
 326                 return 1;
 327
 328         if (lookup_flags & LOOKUP_RCU)
 329                 return -ECHILD;
 330
 331         do_statahead_enter(dir, &dentry, !d_inode(dentry));
 332         ll_statahead_mark(dir, dentry);
 333         return 1;
 334 }
 335
 336 /*
 337  * Always trust cached dentries. Update statahead window if necessary.
 338  */
 339 static int ll_revalidate_nd(struct dentry *dentry, unsigned int flags)
 340 {
 341         CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, flags=%u\n",
 342                dentry, flags);
 343
 344         return ll_revalidate_dentry(dentry, flags);
 345 }
 346
 347 static void ll_d_iput(struct dentry *de, struct inode *inode)
 348 {
 349         LASSERT(inode);
 350         if (!find_cbdata(inode))
 351                 clear_nlink(inode);
 352         iput(inode);
 353 }
 354
 355 const struct dentry_operations ll_d_ops = {
 356         .d_revalidate = ll_revalidate_nd,
 357         .d_release = ll_release,
 358         .d_delete  = ll_ddelete,
 359         .d_iput    = ll_d_iput,
 360         .d_compare = ll_dcompare,
 361 };