fs/aufs/i_op_add.c

   1 /*
   2  * Copyright (C) 2005-2012 Junjiro R. Okajima
   3  *
   4  * This program, aufs is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 /*
  20  * inode operations (add entry)
  21  */
  22
  23 #include "aufs.h"
  24
  25 /*
  26  * final procedure of adding a new entry, except link(2).
  27  * remove whiteout, instantiate, copyup the parent dir's times and size
  28  * and update version.
  29  * if it failed, re-create the removed whiteout.
  30  */
  31 static int epilog(struct inode *dir, aufs_bindex_t bindex,
  32                   struct dentry *wh_dentry, struct dentry *dentry)
  33 {
  34         int err, rerr;
  35         aufs_bindex_t bwh;
  36         struct path h_path;
  37         struct inode *inode, *h_dir;
  38         struct dentry *wh;
  39
  40         bwh = -1;
  41         if (wh_dentry) {
  42                 h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
  43                 IMustLock(h_dir);
  44                 AuDebugOn(au_h_iptr(dir, bindex) != h_dir);
  45                 bwh = au_dbwh(dentry);
  46                 h_path.dentry = wh_dentry;
  47                 h_path.mnt = au_sbr_mnt(dir->i_sb, bindex);
  48                 err = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path,
  49                                           dentry);
  50                 if (unlikely(err))
  51                         goto out;
  52         }
  53
  54         inode = au_new_inode(dentry, /*must_new*/1);
  55         if (!IS_ERR(inode)) {
  56                 d_instantiate(dentry, inode);
  57                 dir = dentry->d_parent->d_inode; /* dir inode is locked */
  58                 IMustLock(dir);
  59                 if (au_ibstart(dir) == au_dbstart(dentry))
  60                         au_cpup_attr_timesizes(dir);
  61                 dir->i_version++;
  62                 return 0; /* success */
  63         }
  64
  65         err = PTR_ERR(inode);
  66         if (!wh_dentry)
  67                 goto out;
  68
  69         /* revert */
  70         /* dir inode is locked */
  71         wh = au_wh_create(dentry, bwh, wh_dentry->d_parent);
  72         rerr = PTR_ERR(wh);
  73         if (IS_ERR(wh)) {
  74                 AuIOErr("%.*s reverting whiteout failed(%d, %d)\n",
  75                         AuDLNPair(dentry), err, rerr);
  76                 err = -EIO;
  77         } else
  78                 dput(wh);
  79
  80 out:
  81         return err;
  82 }
  83
  84 static int au_d_may_add(struct dentry *dentry)
  85 {
  86         int err;
  87
  88         err = 0;
  89         if (unlikely(d_unhashed(dentry)))
  90                 err = -ENOENT;
  91         if (unlikely(dentry->d_inode))
  92                 err = -EEXIST;
  93         return err;
  94 }
  95
  96 /*
  97  * simple tests for the adding inode operations.
  98  * following the checks in vfs, plus the parent-child relationship.
  99  */
 100 int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
 101                struct dentry *h_parent, int isdir)
 102 {
 103         int err;
 104         umode_t h_mode;
 105         struct dentry *h_dentry;
 106         struct inode *h_inode;
 107
 108         err = -ENAMETOOLONG;
 109         if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
 110                 goto out;
 111
 112         h_dentry = au_h_dptr(dentry, bindex);
 113         h_inode = h_dentry->d_inode;
 114         if (!dentry->d_inode) {
 115                 err = -EEXIST;
 116                 if (unlikely(h_inode))
 117                         goto out;
 118         } else {
 119                 /* rename(2) case */
 120                 err = -EIO;
 121                 if (unlikely(!h_inode || !h_inode->i_nlink))
 122                         goto out;
 123
 124                 h_mode = h_inode->i_mode;
 125                 if (!isdir) {
 126                         err = -EISDIR;
 127                         if (unlikely(S_ISDIR(h_mode)))
 128                                 goto out;
 129                 } else if (unlikely(!S_ISDIR(h_mode))) {
 130                         err = -ENOTDIR;
 131                         goto out;
 132                 }
 133         }
 134
 135         err = 0;
 136         /* expected parent dir is locked */
 137         if (unlikely(h_parent != h_dentry->d_parent))
 138                 err = -EIO;
 139
 140 out:
 141         AuTraceErr(err);
 142         return err;
 143 }
 144
 145 /*
 146  * initial procedure of adding a new entry.
 147  * prepare writable branch and the parent dir, lock it,
 148  * and lookup whiteout for the new entry.
 149  */
 150 static struct dentry*
 151 lock_hdir_lkup_wh(struct dentry *dentry, struct au_dtime *dt,
 152                   struct dentry *src_dentry, struct au_pin *pin,
 153                   struct au_wr_dir_args *wr_dir_args)
 154 {
 155         struct dentry *wh_dentry, *h_parent;
 156         struct super_block *sb;
 157         struct au_branch *br;
 158         int err;
 159         unsigned int udba;
 160         aufs_bindex_t bcpup;
 161
 162         AuDbg("%.*s\n", AuDLNPair(dentry));
 163
 164         err = au_wr_dir(dentry, src_dentry, wr_dir_args);
 165         bcpup = err;
 166         wh_dentry = ERR_PTR(err);
 167         if (unlikely(err < 0))
 168                 goto out;
 169
 170         sb = dentry->d_sb;
 171         udba = au_opt_udba(sb);
 172         err = au_pin(pin, dentry, bcpup, udba,
 173                      AuPin_DI_LOCKED | AuPin_MNT_WRITE);
 174         wh_dentry = ERR_PTR(err);
 175         if (unlikely(err))
 176                 goto out;
 177
 178         h_parent = au_pinned_h_parent(pin);
 179         if (udba != AuOpt_UDBA_NONE
 180             && au_dbstart(dentry) == bcpup)
 181                 err = au_may_add(dentry, bcpup, h_parent,
 182                                  au_ftest_wrdir(wr_dir_args->flags, ISDIR));
 183         else if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
 184                 err = -ENAMETOOLONG;
 185         wh_dentry = ERR_PTR(err);
 186         if (unlikely(err))
 187                 goto out_unpin;
 188
 189         br = au_sbr(sb, bcpup);
 190         if (dt) {
 191                 struct path tmp = {
 192                         .dentry = h_parent,
 193                         .mnt    = br->br_mnt
 194                 };
 195                 au_dtime_store(dt, au_pinned_parent(pin), &tmp);
 196         }
 197
 198         wh_dentry = NULL;
 199         if (bcpup != au_dbwh(dentry))
 200                 goto out; /* success */
 201
 202         wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, br);
 203
 204 out_unpin:
 205         if (IS_ERR(wh_dentry))
 206                 au_unpin(pin);
 207 out:
 208         return wh_dentry;
 209 }
 210
 211 /* ---------------------------------------------------------------------- */
 212
 213 enum { Mknod, Symlink, Creat };
 214 struct simple_arg {
 215         int type;
 216         union {
 217                 struct {
 218                         int mode;
 219                         struct nameidata *nd;
 220                 } c;
 221                 struct {
 222                         const char *symname;
 223                 } s;
 224                 struct {
 225                         int mode;
 226                         dev_t dev;
 227                 } m;
 228         } u;
 229 };
 230
 231 static int add_simple(struct inode *dir, struct dentry *dentry,
 232                       struct simple_arg *arg)
 233 {
 234         int err;
 235         aufs_bindex_t bstart;
 236         unsigned char created;
 237         struct au_dtime dt;
 238         struct au_pin pin;
 239         struct path h_path;
 240         struct dentry *wh_dentry, *parent;
 241         struct inode *h_dir;
 242         struct au_wr_dir_args wr_dir_args = {
 243                 .force_btgt     = -1,
 244                 .flags          = AuWrDir_ADD_ENTRY
 245         };
 246
 247         AuDbg("%.*s\n", AuDLNPair(dentry));
 248         IMustLock(dir);
 249
 250         parent = dentry->d_parent; /* dir inode is locked */
 251         err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
 252         if (unlikely(err))
 253                 goto out;
 254         err = au_d_may_add(dentry);
 255         if (unlikely(err))
 256                 goto out_unlock;
 257         di_write_lock_parent(parent);
 258         wh_dentry = lock_hdir_lkup_wh(dentry, &dt, /*src_dentry*/NULL, &pin,
 259                                       &wr_dir_args);
 260         err = PTR_ERR(wh_dentry);
 261         if (IS_ERR(wh_dentry))
 262                 goto out_parent;
 263
 264         bstart = au_dbstart(dentry);
 265         h_path.dentry = au_h_dptr(dentry, bstart);
 266         h_path.mnt = au_sbr_mnt(dentry->d_sb, bstart);
 267         h_dir = au_pinned_h_dir(&pin);
 268         switch (arg->type) {
 269         case Creat:
 270                 err = vfsub_create(h_dir, &h_path, arg->u.c.mode);
 271                 break;
 272         case Symlink:
 273                 err = vfsub_symlink(h_dir, &h_path, arg->u.s.symname);
 274                 break;
 275         case Mknod:
 276                 err = vfsub_mknod(h_dir, &h_path, arg->u.m.mode, arg->u.m.dev);
 277                 break;
 278         default:
 279                 BUG();
 280         }
 281         created = !err;
 282         if (!err)
 283                 err = epilog(dir, bstart, wh_dentry, dentry);
 284
 285         /* revert */
 286         if (unlikely(created && err && h_path.dentry->d_inode)) {
 287                 int rerr;
 288                 rerr = vfsub_unlink(h_dir, &h_path, /*force*/0);
 289                 if (rerr) {
 290                         AuIOErr("%.*s revert failure(%d, %d)\n",
 291                                 AuDLNPair(dentry), err, rerr);
 292                         err = -EIO;
 293                 }
 294                 au_dtime_revert(&dt);
 295         }
 296
 297         au_unpin(&pin);
 298         dput(wh_dentry);
 299
 300 out_parent:
 301         di_write_unlock(parent);
 302 out_unlock:
 303         if (unlikely(err)) {
 304                 au_update_dbstart(dentry);
 305                 d_drop(dentry);
 306         }
 307         aufs_read_unlock(dentry, AuLock_DW);
 308 out:
 309         return err;
 310 }
 311
 312 int aufs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 313 {
 314         struct simple_arg arg = {
 315                 .type = Mknod,
 316                 .u.m = {
 317                         .mode   = mode,
 318                         .dev    = dev
 319                 }
 320         };
 321         return add_simple(dir, dentry, &arg);
 322 }
 323
 324 int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 325 {
 326         struct simple_arg arg = {
 327                 .type = Symlink,
 328                 .u.s.symname = symname
 329         };
 330         return add_simple(dir, dentry, &arg);
 331 }
 332
 333 int aufs_create(struct inode *dir, struct dentry *dentry, int mode,
 334                 struct nameidata *nd)
 335 {
 336         struct simple_arg arg = {
 337                 .type = Creat,
 338                 .u.c = {
 339                         .mode   = mode,
 340                         .nd     = nd
 341                 }
 342         };
 343         return add_simple(dir, dentry, &arg);
 344 }
 345
 346 /* ---------------------------------------------------------------------- */
 347
 348 struct au_link_args {
 349         aufs_bindex_t bdst, bsrc;
 350         struct au_pin pin;
 351         struct path h_path;
 352         struct dentry *src_parent, *parent;
 353 };
 354
 355 static int au_cpup_before_link(struct dentry *src_dentry,
 356                                struct au_link_args *a)
 357 {
 358         int err;
 359         struct dentry *h_src_dentry;
 360         struct mutex *h_mtx;
 361         struct file *h_file;
 362
 363         di_read_lock_parent(a->src_parent, AuLock_IR);
 364         err = au_test_and_cpup_dirs(src_dentry, a->bdst);
 365         if (unlikely(err))
 366                 goto out;
 367
 368         h_src_dentry = au_h_dptr(src_dentry, a->bsrc);
 369         h_mtx = &h_src_dentry->d_inode->i_mutex;
 370         err = au_pin(&a->pin, src_dentry, a->bdst,
 371                      au_opt_udba(src_dentry->d_sb),
 372                      AuPin_DI_LOCKED | AuPin_MNT_WRITE);
 373         if (unlikely(err))
 374                 goto out;
 375         mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
 376         h_file = au_h_open_pre(src_dentry, a->bsrc);
 377         if (IS_ERR(h_file)) {
 378                 err = PTR_ERR(h_file);
 379                 h_file = NULL;
 380         } else
 381                 err = au_sio_cpup_simple(src_dentry, a->bdst, -1,
 382                                          AuCpup_DTIME /* | AuCpup_KEEPLINO */);
 383         mutex_unlock(h_mtx);
 384         au_h_open_post(src_dentry, a->bsrc, h_file);
 385         au_unpin(&a->pin);
 386
 387 out:
 388         di_read_unlock(a->src_parent, AuLock_IR);
 389         return err;
 390 }
 391
 392 static int au_cpup_or_link(struct dentry *src_dentry, struct au_link_args *a)
 393 {
 394         int err;
 395         unsigned char plink;
 396         struct inode *h_inode, *inode;
 397         struct dentry *h_src_dentry;
 398         struct super_block *sb;
 399         struct file *h_file;
 400
 401         plink = 0;
 402         h_inode = NULL;
 403         sb = src_dentry->d_sb;
 404         inode = src_dentry->d_inode;
 405         if (au_ibstart(inode) <= a->bdst)
 406                 h_inode = au_h_iptr(inode, a->bdst);
 407         if (!h_inode || !h_inode->i_nlink) {
 408                 /* copyup src_dentry as the name of dentry. */
 409                 au_set_dbstart(src_dentry, a->bdst);
 410                 au_set_h_dptr(src_dentry, a->bdst, dget(a->h_path.dentry));
 411                 h_inode = au_h_dptr(src_dentry, a->bsrc)->d_inode;
 412                 mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
 413                 h_file = au_h_open_pre(src_dentry, a->bsrc);
 414                 if (IS_ERR(h_file)) {
 415                         err = PTR_ERR(h_file);
 416                         h_file = NULL;
 417                 } else
 418                         err = au_sio_cpup_single(src_dentry, a->bdst, a->bsrc,
 419                                                  -1, AuCpup_KEEPLINO,
 420                                                  a->parent);
 421                 mutex_unlock(&h_inode->i_mutex);
 422                 au_h_open_post(src_dentry, a->bsrc, h_file);
 423                 au_set_h_dptr(src_dentry, a->bdst, NULL);
 424                 au_set_dbstart(src_dentry, a->bsrc);
 425         } else {
 426                 /* the inode of src_dentry already exists on a.bdst branch */
 427                 h_src_dentry = d_find_alias(h_inode);
 428                 if (!h_src_dentry && au_plink_test(inode)) {
 429                         plink = 1;
 430                         h_src_dentry = au_plink_lkup(inode, a->bdst);
 431                         err = PTR_ERR(h_src_dentry);
 432                         if (IS_ERR(h_src_dentry))
 433                                 goto out;
 434
 435                         if (unlikely(!h_src_dentry->d_inode)) {
 436                                 dput(h_src_dentry);
 437                                 h_src_dentry = NULL;
 438                         }
 439
 440                 }
 441                 if (h_src_dentry) {
 442                         err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
 443                                          &a->h_path);
 444                         dput(h_src_dentry);
 445                 } else {
 446                         AuIOErr("no dentry found for hi%lu on b%d\n",
 447                                 h_inode->i_ino, a->bdst);
 448                         err = -EIO;
 449                 }
 450         }
 451
 452         if (!err && !plink)
 453                 au_plink_append(inode, a->bdst, a->h_path.dentry);
 454
 455 out:
 456         AuTraceErr(err);
 457         return err;
 458 }
 459
 460 int aufs_link(struct dentry *src_dentry, struct inode *dir,
 461               struct dentry *dentry)
 462 {
 463         int err, rerr;
 464         struct au_dtime dt;
 465         struct au_link_args *a;
 466         struct dentry *wh_dentry, *h_src_dentry;
 467         struct inode *inode;
 468         struct super_block *sb;
 469         struct au_wr_dir_args wr_dir_args = {
 470                 /* .force_btgt  = -1, */
 471                 .flags          = AuWrDir_ADD_ENTRY
 472         };
 473
 474         IMustLock(dir);
 475         inode = src_dentry->d_inode;
 476         IMustLock(inode);
 477
 478         err = -ENOMEM;
 479         a = kzalloc(sizeof(*a), GFP_NOFS);
 480         if (unlikely(!a))
 481                 goto out;
 482
 483         a->parent = dentry->d_parent; /* dir inode is locked */
 484         err = aufs_read_and_write_lock2(dentry, src_dentry,
 485                                         AuLock_NOPLM | AuLock_GEN);
 486         if (unlikely(err))
 487                 goto out_kfree;
 488         err = au_d_hashed_positive(src_dentry);
 489         if (unlikely(err))
 490                 goto out_unlock;
 491         err = au_d_may_add(dentry);
 492         if (unlikely(err))
 493                 goto out_unlock;
 494
 495         a->src_parent = dget_parent(src_dentry);
 496         wr_dir_args.force_btgt = au_ibstart(inode);
 497
 498         di_write_lock_parent(a->parent);
 499         wr_dir_args.force_btgt = au_wbr(dentry, wr_dir_args.force_btgt);
 500         wh_dentry = lock_hdir_lkup_wh(dentry, &dt, src_dentry, &a->pin,
 501                                       &wr_dir_args);
 502         err = PTR_ERR(wh_dentry);
 503         if (IS_ERR(wh_dentry))
 504                 goto out_parent;
 505
 506         err = 0;
 507         sb = dentry->d_sb;
 508         a->bdst = au_dbstart(dentry);
 509         a->h_path.dentry = au_h_dptr(dentry, a->bdst);
 510         a->h_path.mnt = au_sbr_mnt(sb, a->bdst);
 511         a->bsrc = au_ibstart(inode);
 512         h_src_dentry = au_h_d_alias(src_dentry, a->bsrc);
 513         if (!h_src_dentry) {
 514                 a->bsrc = au_dbstart(src_dentry);
 515                 h_src_dentry = au_h_d_alias(src_dentry, a->bsrc);
 516                 AuDebugOn(!h_src_dentry);
 517         } else if (IS_ERR(h_src_dentry))
 518                 goto out_parent;
 519
 520         if (au_opt_test(au_mntflags(sb), PLINK)) {
 521                 if (a->bdst < a->bsrc
 522                     /* && h_src_dentry->d_sb != a->h_path.dentry->d_sb */)
 523                         err = au_cpup_or_link(src_dentry, a);
 524                 else
 525                         err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
 526                                          &a->h_path);
 527                 dput(h_src_dentry);
 528         } else {
 529                 /*
 530                  * copyup src_dentry to the branch we process,
 531                  * and then link(2) to it.
 532                  */
 533                 dput(h_src_dentry);
 534                 if (a->bdst < a->bsrc
 535                     /* && h_src_dentry->d_sb != a->h_path.dentry->d_sb */) {
 536                         au_unpin(&a->pin);
 537                         di_write_unlock(a->parent);
 538                         err = au_cpup_before_link(src_dentry, a);
 539                         di_write_lock_parent(a->parent);
 540                         if (!err)
 541                                 err = au_pin(&a->pin, dentry, a->bdst,
 542                                              au_opt_udba(sb),
 543                                              AuPin_DI_LOCKED | AuPin_MNT_WRITE);
 544                         if (unlikely(err))
 545                                 goto out_wh;
 546                 }
 547                 if (!err) {
 548                         h_src_dentry = au_h_dptr(src_dentry, a->bdst);
 549                         err = -ENOENT;
 550                         if (h_src_dentry && h_src_dentry->d_inode)
 551                                 err = vfsub_link(h_src_dentry,
 552                                                  au_pinned_h_dir(&a->pin),
 553                                                  &a->h_path);
 554                 }
 555         }
 556         if (unlikely(err))
 557                 goto out_unpin;
 558
 559         if (wh_dentry) {
 560                 a->h_path.dentry = wh_dentry;
 561                 err = au_wh_unlink_dentry(au_pinned_h_dir(&a->pin), &a->h_path,
 562                                           dentry);
 563                 if (unlikely(err))
 564                         goto out_revert;
 565         }
 566
 567         dir->i_version++;
 568         if (au_ibstart(dir) == au_dbstart(dentry))
 569                 au_cpup_attr_timesizes(dir);
 570         inc_nlink(inode);
 571         inode->i_ctime = dir->i_ctime;
 572         d_instantiate(dentry, au_igrab(inode));
 573         if (d_unhashed(a->h_path.dentry))
 574                 /* some filesystem calls d_drop() */
 575                 d_drop(dentry);
 576         goto out_unpin; /* success */
 577
 578 out_revert:
 579         rerr = vfsub_unlink(au_pinned_h_dir(&a->pin), &a->h_path, /*force*/0);
 580         if (unlikely(rerr)) {
 581                 AuIOErr("%.*s reverting failed(%d, %d)\n",
 582                         AuDLNPair(dentry), err, rerr);
 583                 err = -EIO;
 584         }
 585         au_dtime_revert(&dt);
 586 out_unpin:
 587         au_unpin(&a->pin);
 588 out_wh:
 589         dput(wh_dentry);
 590 out_parent:
 591         di_write_unlock(a->parent);
 592         dput(a->src_parent);
 593 out_unlock:
 594         if (unlikely(err)) {
 595                 au_update_dbstart(dentry);
 596                 d_drop(dentry);
 597         }
 598         aufs_read_and_write_unlock2(dentry, src_dentry);
 599 out_kfree:
 600         kfree(a);
 601 out:
 602         return err;
 603 }
 604
 605 int aufs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 606 {
 607         int err, rerr;
 608         aufs_bindex_t bindex;
 609         unsigned char diropq;
 610         struct path h_path;
 611         struct dentry *wh_dentry, *parent, *opq_dentry;
 612         struct mutex *h_mtx;
 613         struct super_block *sb;
 614         struct {
 615                 struct au_pin pin;
 616                 struct au_dtime dt;
 617         } *a; /* reduce the stack usage */
 618         struct au_wr_dir_args wr_dir_args = {
 619                 .force_btgt     = -1,
 620                 .flags          = AuWrDir_ADD_ENTRY | AuWrDir_ISDIR
 621         };
 622
 623         IMustLock(dir);
 624
 625         err = -ENOMEM;
 626         a = kmalloc(sizeof(*a), GFP_NOFS);
 627         if (unlikely(!a))
 628                 goto out;
 629
 630         err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
 631         if (unlikely(err))
 632                 goto out_free;
 633         err = au_d_may_add(dentry);
 634         if (unlikely(err))
 635                 goto out_unlock;
 636
 637         parent = dentry->d_parent; /* dir inode is locked */
 638         di_write_lock_parent(parent);
 639         wh_dentry = lock_hdir_lkup_wh(dentry, &a->dt, /*src_dentry*/NULL,
 640                                       &a->pin, &wr_dir_args);
 641         err = PTR_ERR(wh_dentry);
 642         if (IS_ERR(wh_dentry))
 643                 goto out_parent;
 644
 645         sb = dentry->d_sb;
 646         bindex = au_dbstart(dentry);
 647         h_path.dentry = au_h_dptr(dentry, bindex);
 648         h_path.mnt = au_sbr_mnt(sb, bindex);
 649         err = vfsub_mkdir(au_pinned_h_dir(&a->pin), &h_path, mode);
 650         if (unlikely(err))
 651                 goto out_unpin;
 652
 653         /* make the dir opaque */
 654         diropq = 0;
 655         h_mtx = &h_path.dentry->d_inode->i_mutex;
 656         if (wh_dentry
 657             || au_opt_test(au_mntflags(sb), ALWAYS_DIROPQ)) {
 658                 mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
 659                 opq_dentry = au_diropq_create(dentry, bindex);
 660                 mutex_unlock(h_mtx);
 661                 err = PTR_ERR(opq_dentry);
 662                 if (IS_ERR(opq_dentry))
 663                         goto out_dir;
 664                 dput(opq_dentry);
 665                 diropq = 1;
 666         }
 667
 668         err = epilog(dir, bindex, wh_dentry, dentry);
 669         if (!err) {
 670                 inc_nlink(dir);
 671                 goto out_unpin; /* success */
 672         }
 673
 674         /* revert */
 675         if (diropq) {
 676                 AuLabel(revert opq);
 677                 mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
 678                 rerr = au_diropq_remove(dentry, bindex);
 679                 mutex_unlock(h_mtx);
 680                 if (rerr) {
 681                         AuIOErr("%.*s reverting diropq failed(%d, %d)\n",
 682                                 AuDLNPair(dentry), err, rerr);
 683                         err = -EIO;
 684                 }
 685         }
 686
 687 out_dir:
 688         AuLabel(revert dir);
 689         rerr = vfsub_rmdir(au_pinned_h_dir(&a->pin), &h_path);
 690         if (rerr) {
 691                 AuIOErr("%.*s reverting dir failed(%d, %d)\n",
 692                         AuDLNPair(dentry), err, rerr);
 693                 err = -EIO;
 694         }
 695         au_dtime_revert(&a->dt);
 696 out_unpin:
 697         au_unpin(&a->pin);
 698         dput(wh_dentry);
 699 out_parent:
 700         di_write_unlock(parent);
 701 out_unlock:
 702         if (unlikely(err)) {
 703                 au_update_dbstart(dentry);
 704                 d_drop(dentry);
 705         }
 706         aufs_read_unlock(dentry, AuLock_DW);
 707 out_free:
 708         kfree(a);
 709 out:
 710         return err;
 711 }