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_lite.h"
  41 #include "../include/lustre/lustre_idl.h"
  42 #include "../include/lustre_dlm.h"
  43
  44 #include "llite_internal.h"
  45
  46 static void free_dentry_data(struct rcu_head *head)
  47 {
  48         struct ll_dentry_data *lld;
  49
  50         lld = container_of(head, struct ll_dentry_data, lld_rcu_head);
  51         kfree(lld);
  52 }
  53
  54 /* should NOT be called with the dcache lock, see fs/dcache.c */
  55 static void ll_release(struct dentry *de)
  56 {
  57         struct ll_dentry_data *lld;
  58
  59         LASSERT(de);
  60         lld = ll_d2d(de);
  61         if (!lld) /* NFS copies the de->d_op methods (bug 4655) */
  62                 return;
  63
  64         if (lld->lld_it) {
  65                 ll_intent_release(lld->lld_it);
  66                 kfree(lld->lld_it);
  67         }
  68
  69         de->d_fsdata = NULL;
  70         call_rcu(&lld->lld_rcu_head, free_dentry_data);
  71 }
  72
  73 /* Compare if two dentries are the same.  Don't match if the existing dentry
  74  * is marked invalid.  Returns 1 if different, 0 if the same.
  75  *
  76  * This avoids a race where ll_lookup_it() instantiates a dentry, but we get
  77  * an AST before calling d_revalidate_it().  The dentry still exists (marked
  78  * INVALID) so d_lookup() matches it, but we have no lock on it (so
  79  * lock_match() fails) and we spin around real_lookup().
  80  */
  81 static int ll_dcompare(const struct dentry *parent, const struct dentry *dentry,
  82                        unsigned int len, const char *str,
  83                        const struct qstr *name)
  84 {
  85         if (len != name->len)
  86                 return 1;
  87
  88         if (memcmp(str, name->name, len))
  89                 return 1;
  90
  91         CDEBUG(D_DENTRY, "found name %.*s(%p) flags %#x refc %d\n",
  92                name->len, name->name, dentry, dentry->d_flags,
  93                d_count(dentry));
  94
  95         /* mountpoint is always valid */
  96         if (d_mountpoint((struct dentry *)dentry))
  97                 return 0;
  98
  99         if (d_lustre_invalid(dentry))
 100                 return 1;
 101
 102         return 0;
 103 }
 104
 105 static inline int return_if_equal(struct ldlm_lock *lock, void *data)
 106 {
 107         return (ldlm_is_canceling(lock) && ldlm_is_discard_data(lock)) ?
 108                 LDLM_ITER_CONTINUE : LDLM_ITER_STOP;
 109 }
 110
 111 /* find any ldlm lock of the inode in mdc and lov
 112  * return 0    not find
 113  *      1    find one
 114  *      < 0    error
 115  */
 116 static int find_cbdata(struct inode *inode)
 117 {
 118         struct ll_sb_info *sbi = ll_i2sbi(inode);
 119         struct lov_stripe_md *lsm;
 120         int rc = 0;
 121
 122         LASSERT(inode);
 123         rc = md_find_cbdata(sbi->ll_md_exp, ll_inode2fid(inode),
 124                             return_if_equal, NULL);
 125         if (rc != 0)
 126                 return rc;
 127
 128         lsm = ccc_inode_lsm_get(inode);
 129         if (!lsm)
 130                 return rc;
 131
 132         rc = obd_find_cbdata(sbi->ll_dt_exp, lsm, return_if_equal, NULL);
 133         ccc_inode_lsm_put(inode, lsm);
 134
 135         return rc;
 136 }
 137
 138 /**
 139  * Called when last reference to a dentry is dropped and dcache wants to know
 140  * whether or not it should cache it:
 141  * - return 1 to delete the dentry immediately
 142  * - return 0 to cache the dentry
 143  * Should NOT be called with the dcache lock, see fs/dcache.c
 144  */
 145 static int ll_ddelete(const struct dentry *de)
 146 {
 147         LASSERT(de);
 148
 149         CDEBUG(D_DENTRY, "%s dentry %pd (%p, parent %p, inode %p) %s%s\n",
 150                d_lustre_invalid((struct dentry *)de) ? "deleting" : "keeping",
 151                de, de, de->d_parent, d_inode(de),
 152                d_unhashed(de) ? "" : "hashed,",
 153                list_empty(&de->d_subdirs) ? "" : "subdirs");
 154
 155         /* kernel >= 2.6.38 last refcount is decreased after this function. */
 156         LASSERT(d_count(de) == 1);
 157
 158         /* Disable this piece of code temporarily because this is called
 159          * inside dcache_lock so it's not appropriate to do lots of work
 160          * here. ATTENTION: Before this piece of code enabling, LU-2487 must be
 161          * resolved.
 162          */
 163 #if 0
 164         /* if not ldlm lock for this inode, set i_nlink to 0 so that
 165          * this inode can be recycled later b=20433
 166          */
 167         if (d_really_is_positive(de) && !find_cbdata(d_inode(de)))
 168                 clear_nlink(d_inode(de));
 169 #endif
 170
 171         if (d_lustre_invalid((struct dentry *)de))
 172                 return 1;
 173         return 0;
 174 }
 175
 176 int ll_d_init(struct dentry *de)
 177 {
 178         CDEBUG(D_DENTRY, "ldd on dentry %pd (%p) parent %p inode %p refc %d\n",
 179                de, de, de->d_parent, d_inode(de), d_count(de));
 180
 181         if (!de->d_fsdata) {
 182                 struct ll_dentry_data *lld;
 183
 184                 lld = kzalloc(sizeof(*lld), GFP_NOFS);
 185                 if (likely(lld)) {
 186                         spin_lock(&de->d_lock);
 187                         if (likely(!de->d_fsdata)) {
 188                                 de->d_fsdata = lld;
 189                                 __d_lustre_invalidate(de);
 190                         } else {
 191                                 kfree(lld);
 192                         }
 193                         spin_unlock(&de->d_lock);
 194                 } else {
 195                         return -ENOMEM;
 196                 }
 197         }
 198         LASSERT(de->d_op == &ll_d_ops);
 199
 200         return 0;
 201 }
 202
 203 void ll_intent_drop_lock(struct lookup_intent *it)
 204 {
 205         if (it->it_op && it->it_lock_mode) {
 206                 struct lustre_handle handle;
 207
 208                 handle.cookie = it->it_lock_handle;
 209
 210                 CDEBUG(D_DLMTRACE, "releasing lock with cookie %#llx from it %p\n",
 211                        handle.cookie, it);
 212                 ldlm_lock_decref(&handle, it->it_lock_mode);
 213
 214                 /* bug 494: intent_release may be called multiple times, from
 215                  * this thread and we don't want to double-decref this lock
 216                  */
 217                 it->it_lock_mode = 0;
 218                 if (it->it_remote_lock_mode != 0) {
 219                         handle.cookie = it->it_remote_lock_handle;
 220
 221                         CDEBUG(D_DLMTRACE, "releasing remote lock with cookie%#llx from it %p\n",
 222                                handle.cookie, it);
 223                         ldlm_lock_decref(&handle,
 224                                          it->it_remote_lock_mode);
 225                         it->it_remote_lock_mode = 0;
 226                 }
 227         }
 228 }
 229
 230 void ll_intent_release(struct lookup_intent *it)
 231 {
 232         CDEBUG(D_INFO, "intent %p released\n", it);
 233         ll_intent_drop_lock(it);
 234         /* We are still holding extra reference on a request, need to free it */
 235         if (it_disposition(it, DISP_ENQ_OPEN_REF))
 236                 ptlrpc_req_finished(it->it_request); /* ll_file_open */
 237
 238         if (it_disposition(it, DISP_ENQ_CREATE_REF)) /* create rec */
 239                 ptlrpc_req_finished(it->it_request);
 240
 241         it->it_disposition = 0;
 242         it->it_request = NULL;
 243 }
 244
 245 void ll_invalidate_aliases(struct inode *inode)
 246 {
 247         struct dentry *dentry;
 248
 249         CDEBUG(D_INODE, "marking dentries for ino "DFID"(%p) invalid\n",
 250                PFID(ll_inode2fid(inode)), inode);
 251
 252         spin_lock(&inode->i_lock);
 253         hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 254                 CDEBUG(D_DENTRY, "dentry in drop %pd (%p) parent %p inode %p flags %d\n",
 255                        dentry, dentry, dentry->d_parent,
 256                        d_inode(dentry), dentry->d_flags);
 257
 258                 d_lustre_invalidate(dentry, 0);
 259         }
 260         spin_unlock(&inode->i_lock);
 261 }
 262
 263 int ll_revalidate_it_finish(struct ptlrpc_request *request,
 264                             struct lookup_intent *it,
 265                             struct inode *inode)
 266 {
 267         int rc = 0;
 268
 269         if (!request)
 270                 return 0;
 271
 272         if (it_disposition(it, DISP_LOOKUP_NEG))
 273                 return -ENOENT;
 274
 275         rc = ll_prep_inode(&inode, request, NULL, it);
 276
 277         return rc;
 278 }
 279
 280 void ll_lookup_finish_locks(struct lookup_intent *it, struct inode *inode)
 281 {
 282         if (it->it_lock_mode && inode) {
 283                 struct ll_sb_info *sbi = ll_i2sbi(inode);
 284
 285                 CDEBUG(D_DLMTRACE, "setting l_data to inode "DFID"(%p)\n",
 286                        PFID(ll_inode2fid(inode)), inode);
 287                 ll_set_lock_data(sbi->ll_md_exp, inode, it, NULL);
 288         }
 289
 290         /* drop lookup or getattr locks immediately */
 291         if (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR) {
 292                 /* on 2.6 there are situation when several lookups and
 293                  * revalidations may be requested during single operation.
 294                  * therefore, we don't release intent here -bzzz
 295                  */
 296                 ll_intent_drop_lock(it);
 297         }
 298 }
 299
 300 static int ll_revalidate_dentry(struct dentry *dentry,
 301                                 unsigned int lookup_flags)
 302 {
 303         struct inode *dir = d_inode(dentry->d_parent);
 304
 305         /* If this is intermediate component path lookup and we were able to get
 306          * to this dentry, then its lock has not been revoked and the
 307          * path component is valid.
 308          */
 309         if (lookup_flags & LOOKUP_PARENT)
 310                 return 1;
 311
 312         /* Symlink - always valid as long as the dentry was found */
 313         if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode))
 314                 return 1;
 315
 316         /*
 317          * if open&create is set, talk to MDS to make sure file is created if
 318          * necessary, because we can't do this in ->open() later since that's
 319          * called on an inode. return 0 here to let lookup to handle this.
 320          */
 321         if ((lookup_flags & (LOOKUP_OPEN | LOOKUP_CREATE)) ==
 322             (LOOKUP_OPEN | LOOKUP_CREATE))
 323                 return 0;
 324
 325         if (lookup_flags & (LOOKUP_PARENT | LOOKUP_OPEN | LOOKUP_CREATE))
 326                 return 1;
 327
 328         if (d_need_statahead(dir, dentry) <= 0)
 329                 return 1;
 330
 331         if (lookup_flags & LOOKUP_RCU)
 332                 return -ECHILD;
 333
 334         do_statahead_enter(dir, &dentry, !d_inode(dentry));
 335         ll_statahead_mark(dir, dentry);
 336         return 1;
 337 }
 338
 339 /*
 340  * Always trust cached dentries. Update statahead window if necessary.
 341  */
 342 static int ll_revalidate_nd(struct dentry *dentry, unsigned int flags)
 343 {
 344         CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, flags=%u\n",
 345                dentry, flags);
 346
 347         return ll_revalidate_dentry(dentry, flags);
 348 }
 349
 350 static void ll_d_iput(struct dentry *de, struct inode *inode)
 351 {
 352         LASSERT(inode);
 353         if (!find_cbdata(inode))
 354                 clear_nlink(inode);
 355         iput(inode);
 356 }
 357
 358 const struct dentry_operations ll_d_ops = {
 359         .d_revalidate = ll_revalidate_nd,
 360         .d_release = ll_release,
 361         .d_delete  = ll_ddelete,
 362         .d_iput    = ll_d_iput,
 363         .d_compare = ll_dcompare,
 364 };