fs/ocfs2/dir.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * dir.c
   5  *
   6  * Creates, reads, walks and deletes directory-nodes
   7  *
   8  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
   9  *
  10  *  Portions of this code from linux/fs/ext3/dir.c
  11  *
  12  *  Copyright (C) 1992, 1993, 1994, 1995
  13  *  Remy Card (card@masi.ibp.fr)
  14  *  Laboratoire MASI - Institut Blaise pascal
  15  *  Universite Pierre et Marie Curie (Paris VI)
  16  *
  17  *   from
  18  *
  19  *   linux/fs/minix/dir.c
  20  *
  21  *   Copyright (C) 1991, 1992 Linux Torvalds
  22  *
  23  * This program is free software; you can redistribute it and/or
  24  * modify it under the terms of the GNU General Public
  25  * License as published by the Free Software Foundation; either
  26  * version 2 of the License, or (at your option) any later version.
  27  *
  28  * This program is distributed in the hope that it will be useful,
  29  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  30  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  31  * General Public License for more details.
  32  *
  33  * You should have received a copy of the GNU General Public
  34  * License along with this program; if not, write to the
  35  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  36  * Boston, MA 021110-1307, USA.
  37  */
  38
  39 #include <linux/fs.h>
  40 #include <linux/types.h>
  41 #include <linux/slab.h>
  42 #include <linux/highmem.h>
  43
  44 #define MLOG_MASK_PREFIX ML_NAMEI
  45 #include <cluster/masklog.h>
  46
  47 #include "ocfs2.h"
  48
  49 #include "alloc.h"
  50 #include "dir.h"
  51 #include "dlmglue.h"
  52 #include "extent_map.h"
  53 #include "file.h"
  54 #include "inode.h"
  55 #include "journal.h"
  56 #include "namei.h"
  57 #include "suballoc.h"
  58 #include "uptodate.h"
  59
  60 #include "buffer_head_io.h"
  61
  62 static unsigned char ocfs2_filetype_table[] = {
  63         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
  64 };
  65
  66 static int ocfs2_extend_dir(struct ocfs2_super *osb,
  67                             struct inode *dir,
  68                             struct buffer_head *parent_fe_bh,
  69                             struct buffer_head **new_de_bh);
  70 /*
  71  * ocfs2_readdir()
  72  *
  73  */
  74 int ocfs2_readdir(struct file * filp, void * dirent, filldir_t filldir)
  75 {
  76         int error = 0;
  77         unsigned long offset, blk, last_ra_blk = 0;
  78         int i, stored;
  79         struct buffer_head * bh, * tmp;
  80         struct ocfs2_dir_entry * de;
  81         int err;
  82         struct inode *inode = filp->f_dentry->d_inode;
  83         struct super_block * sb = inode->i_sb;
  84         unsigned int ra_sectors = 16;
  85         int lock_level = 0;
  86
  87         mlog_entry("dirino=%llu\n",
  88                    (unsigned long long)OCFS2_I(inode)->ip_blkno);
  89
  90         stored = 0;
  91         bh = NULL;
  92
  93         error = ocfs2_meta_lock_atime(inode, filp->f_vfsmnt, &lock_level);
  94         if (lock_level && error >= 0) {
  95                 /* We release EX lock which used to update atime
  96                  * and get PR lock again to reduce contention
  97                  * on commonly accessed directories. */
  98                 ocfs2_meta_unlock(inode, 1);
  99                 lock_level = 0;
 100                 error = ocfs2_meta_lock(inode, NULL, 0);
 101         }
 102         if (error < 0) {
 103                 if (error != -ENOENT)
 104                         mlog_errno(error);
 105                 /* we haven't got any yet, so propagate the error. */
 106                 stored = error;
 107                 goto bail_nolock;
 108         }
 109
 110         offset = filp->f_pos & (sb->s_blocksize - 1);
 111
 112         while (!error && !stored && filp->f_pos < i_size_read(inode)) {
 113                 blk = (filp->f_pos) >> sb->s_blocksize_bits;
 114                 bh = ocfs2_bread(inode, blk, &err, 0);
 115                 if (!bh) {
 116                         mlog(ML_ERROR,
 117                              "directory #%llu contains a hole at offset %lld\n",
 118                              (unsigned long long)OCFS2_I(inode)->ip_blkno,
 119                              filp->f_pos);
 120                         filp->f_pos += sb->s_blocksize - offset;
 121                         continue;
 122                 }
 123
 124                 /* The idea here is to begin with 8k read-ahead and to stay
 125                  * 4k ahead of our current position.
 126                  *
 127                  * TODO: Use the pagecache for this. We just need to
 128                  * make sure it's cluster-safe... */
 129                 if (!last_ra_blk
 130                     || (((last_ra_blk - blk) << 9) <= (ra_sectors / 2))) {
 131                         for (i = ra_sectors >> (sb->s_blocksize_bits - 9);
 132                              i > 0; i--) {
 133                                 tmp = ocfs2_bread(inode, ++blk, &err, 1);
 134                                 if (tmp)
 135                                         brelse(tmp);
 136                         }
 137                         last_ra_blk = blk;
 138                         ra_sectors = 8;
 139                 }
 140
 141 revalidate:
 142                 /* If the dir block has changed since the last call to
 143                  * readdir(2), then we might be pointing to an invalid
 144                  * dirent right now.  Scan from the start of the block
 145                  * to make sure. */
 146                 if (filp->f_version != inode->i_version) {
 147                         for (i = 0; i < sb->s_blocksize && i < offset; ) {
 148                                 de = (struct ocfs2_dir_entry *) (bh->b_data + i);
 149                                 /* It's too expensive to do a full
 150                                  * dirent test each time round this
 151                                  * loop, but we do have to test at
 152                                  * least that it is non-zero.  A
 153                                  * failure will be detected in the
 154                                  * dirent test below. */
 155                                 if (le16_to_cpu(de->rec_len) <
 156                                     OCFS2_DIR_REC_LEN(1))
 157                                         break;
 158                                 i += le16_to_cpu(de->rec_len);
 159                         }
 160                         offset = i;
 161                         filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
 162                                 | offset;
 163                         filp->f_version = inode->i_version;
 164                 }
 165
 166                 while (!error && filp->f_pos < i_size_read(inode)
 167                        && offset < sb->s_blocksize) {
 168                         de = (struct ocfs2_dir_entry *) (bh->b_data + offset);
 169                         if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
 170                                 /* On error, skip the f_pos to the
 171                                    next block. */
 172                                 filp->f_pos = (filp->f_pos |
 173                                                (sb->s_blocksize - 1)) + 1;
 174                                 brelse(bh);
 175                                 goto bail;
 176                         }
 177                         offset += le16_to_cpu(de->rec_len);
 178                         if (le64_to_cpu(de->inode)) {
 179                                 /* We might block in the next section
 180                                  * if the data destination is
 181                                  * currently swapped out.  So, use a
 182                                  * version stamp to detect whether or
 183                                  * not the directory has been modified
 184                                  * during the copy operation.
 185                                  */
 186                                 unsigned long version = filp->f_version;
 187                                 unsigned char d_type = DT_UNKNOWN;
 188
 189                                 if (de->file_type < OCFS2_FT_MAX)
 190                                         d_type = ocfs2_filetype_table[de->file_type];
 191                                 error = filldir(dirent, de->name,
 192                                                 de->name_len,
 193                                                 filp->f_pos,
 194                                                 ino_from_blkno(sb, le64_to_cpu(de->inode)),
 195                                                 d_type);
 196                                 if (error)
 197                                         break;
 198                                 if (version != filp->f_version)
 199                                         goto revalidate;
 200                                 stored ++;
 201                         }
 202                         filp->f_pos += le16_to_cpu(de->rec_len);
 203                 }
 204                 offset = 0;
 205                 brelse(bh);
 206         }
 207
 208         stored = 0;
 209 bail:
 210         ocfs2_meta_unlock(inode, lock_level);
 211
 212 bail_nolock:
 213         mlog_exit(stored);
 214
 215         return stored;
 216 }
 217
 218 /*
 219  * NOTE: this should always be called with parent dir i_mutex taken.
 220  */
 221 int ocfs2_find_files_on_disk(const char *name,
 222                              int namelen,
 223                              u64 *blkno,
 224                              struct inode *inode,
 225                              struct buffer_head **dirent_bh,
 226                              struct ocfs2_dir_entry **dirent)
 227 {
 228         int status = -ENOENT;
 229
 230         mlog_entry("(name=%.*s, blkno=%p, inode=%p, dirent_bh=%p, dirent=%p)\n",
 231                    namelen, name, blkno, inode, dirent_bh, dirent);
 232
 233         *dirent_bh = ocfs2_find_entry(name, namelen, inode, dirent);
 234         if (!*dirent_bh || !*dirent) {
 235                 status = -ENOENT;
 236                 goto leave;
 237         }
 238
 239         *blkno = le64_to_cpu((*dirent)->inode);
 240
 241         status = 0;
 242 leave:
 243         if (status < 0) {
 244                 *dirent = NULL;
 245                 if (*dirent_bh) {
 246                         brelse(*dirent_bh);
 247                         *dirent_bh = NULL;
 248                 }
 249         }
 250
 251         mlog_exit(status);
 252         return status;
 253 }
 254
 255 /* Check for a name within a directory.
 256  *
 257  * Return 0 if the name does not exist
 258  * Return -EEXIST if the directory contains the name
 259  *
 260  * Callers should have i_mutex + a cluster lock on dir
 261  */
 262 int ocfs2_check_dir_for_entry(struct inode *dir,
 263                               const char *name,
 264                               int namelen)
 265 {
 266         int ret;
 267         struct buffer_head *dirent_bh = NULL;
 268         struct ocfs2_dir_entry *dirent = NULL;
 269
 270         mlog_entry("dir %llu, name '%.*s'\n",
 271                    (unsigned long long)OCFS2_I(dir)->ip_blkno, namelen, name);
 272
 273         ret = -EEXIST;
 274         dirent_bh = ocfs2_find_entry(name, namelen, dir, &dirent);
 275         if (dirent_bh)
 276                 goto bail;
 277
 278         ret = 0;
 279 bail:
 280         if (dirent_bh)
 281                 brelse(dirent_bh);
 282
 283         mlog_exit(ret);
 284         return ret;
 285 }
 286
 287 /*
 288  * routine to check that the specified directory is empty (for rmdir)
 289  */
 290 int ocfs2_empty_dir(struct inode *inode)
 291 {
 292         unsigned long offset;
 293         struct buffer_head * bh;
 294         struct ocfs2_dir_entry * de, * de1;
 295         struct super_block * sb;
 296         int err;
 297
 298         sb = inode->i_sb;
 299         if ((i_size_read(inode) <
 300              (OCFS2_DIR_REC_LEN(1) + OCFS2_DIR_REC_LEN(2))) ||
 301             !(bh = ocfs2_bread(inode, 0, &err, 0))) {
 302                 mlog(ML_ERROR, "bad directory (dir #%llu) - no data block\n",
 303                      (unsigned long long)OCFS2_I(inode)->ip_blkno);
 304                 return 1;
 305         }
 306
 307         de = (struct ocfs2_dir_entry *) bh->b_data;
 308         de1 = (struct ocfs2_dir_entry *)
 309                         ((char *)de + le16_to_cpu(de->rec_len));
 310         if ((le64_to_cpu(de->inode) != OCFS2_I(inode)->ip_blkno) ||
 311                         !le64_to_cpu(de1->inode) ||
 312                         strcmp(".", de->name) ||
 313                         strcmp("..", de1->name)) {
 314                 mlog(ML_ERROR, "bad directory (dir #%llu) - no `.' or `..'\n",
 315                      (unsigned long long)OCFS2_I(inode)->ip_blkno);
 316                 brelse(bh);
 317                 return 1;
 318         }
 319         offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
 320         de = (struct ocfs2_dir_entry *)((char *)de1 + le16_to_cpu(de1->rec_len));
 321         while (offset < i_size_read(inode) ) {
 322                 if (!bh || (void *)de >= (void *)(bh->b_data + sb->s_blocksize)) {
 323                         brelse(bh);
 324                         bh = ocfs2_bread(inode,
 325                                          offset >> sb->s_blocksize_bits, &err, 0);
 326                         if (!bh) {
 327                                 mlog(ML_ERROR, "dir %llu has a hole at %lu\n",
 328                                      (unsigned long long)OCFS2_I(inode)->ip_blkno, offset);
 329                                 offset += sb->s_blocksize;
 330                                 continue;
 331                         }
 332                         de = (struct ocfs2_dir_entry *) bh->b_data;
 333                 }
 334                 if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
 335                         brelse(bh);
 336                         return 1;
 337                 }
 338                 if (le64_to_cpu(de->inode)) {
 339                         brelse(bh);
 340                         return 0;
 341                 }
 342                 offset += le16_to_cpu(de->rec_len);
 343                 de = (struct ocfs2_dir_entry *)
 344                         ((char *)de + le16_to_cpu(de->rec_len));
 345         }
 346         brelse(bh);
 347         return 1;
 348 }
 349
 350 /* returns a bh of the 1st new block in the allocation. */
 351 int ocfs2_do_extend_dir(struct super_block *sb,
 352                         handle_t *handle,
 353                         struct inode *dir,
 354                         struct buffer_head *parent_fe_bh,
 355                         struct ocfs2_alloc_context *data_ac,
 356                         struct ocfs2_alloc_context *meta_ac,
 357                         struct buffer_head **new_bh)
 358 {
 359         int status;
 360         int extend;
 361         u64 p_blkno;
 362
 363         spin_lock(&OCFS2_I(dir)->ip_lock);
 364         extend = (i_size_read(dir) == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters));
 365         spin_unlock(&OCFS2_I(dir)->ip_lock);
 366
 367         if (extend) {
 368                 status = ocfs2_do_extend_allocation(OCFS2_SB(sb), dir, 1,
 369                                                     parent_fe_bh, handle,
 370                                                     data_ac, meta_ac, NULL);
 371                 BUG_ON(status == -EAGAIN);
 372                 if (status < 0) {
 373                         mlog_errno(status);
 374                         goto bail;
 375                 }
 376         }
 377
 378         status = ocfs2_extent_map_get_blocks(dir, (dir->i_blocks >>
 379                                                    (sb->s_blocksize_bits - 9)),
 380                                              1, &p_blkno, NULL);
 381         if (status < 0) {
 382                 mlog_errno(status);
 383                 goto bail;
 384         }
 385
 386         *new_bh = sb_getblk(sb, p_blkno);
 387         if (!*new_bh) {
 388                 status = -EIO;
 389                 mlog_errno(status);
 390                 goto bail;
 391         }
 392         status = 0;
 393 bail:
 394         mlog_exit(status);
 395         return status;
 396 }
 397
 398 /* assumes you already have a cluster lock on the directory. */
 399 static int ocfs2_extend_dir(struct ocfs2_super *osb,
 400                             struct inode *dir,
 401                             struct buffer_head *parent_fe_bh,
 402                             struct buffer_head **new_de_bh)
 403 {
 404         int status = 0;
 405         int credits, num_free_extents;
 406         loff_t dir_i_size;
 407         struct ocfs2_dinode *fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
 408         struct ocfs2_alloc_context *data_ac = NULL;
 409         struct ocfs2_alloc_context *meta_ac = NULL;
 410         handle_t *handle = NULL;
 411         struct buffer_head *new_bh = NULL;
 412         struct ocfs2_dir_entry * de;
 413         struct super_block *sb = osb->sb;
 414
 415         mlog_entry_void();
 416
 417         dir_i_size = i_size_read(dir);
 418         mlog(0, "extending dir %llu (i_size = %lld)\n",
 419              (unsigned long long)OCFS2_I(dir)->ip_blkno, dir_i_size);
 420
 421         /* dir->i_size is always block aligned. */
 422         spin_lock(&OCFS2_I(dir)->ip_lock);
 423         if (dir_i_size == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters)) {
 424                 spin_unlock(&OCFS2_I(dir)->ip_lock);
 425                 num_free_extents = ocfs2_num_free_extents(osb, dir, fe);
 426                 if (num_free_extents < 0) {
 427                         status = num_free_extents;
 428                         mlog_errno(status);
 429                         goto bail;
 430                 }
 431
 432                 if (!num_free_extents) {
 433                         status = ocfs2_reserve_new_metadata(osb, fe, &meta_ac);
 434                         if (status < 0) {
 435                                 if (status != -ENOSPC)
 436                                         mlog_errno(status);
 437                                 goto bail;
 438                         }
 439                 }
 440
 441                 status = ocfs2_reserve_clusters(osb, 1, &data_ac);
 442                 if (status < 0) {
 443                         if (status != -ENOSPC)
 444                                 mlog_errno(status);
 445                         goto bail;
 446                 }
 447
 448                 credits = ocfs2_calc_extend_credits(sb, fe, 1);
 449         } else {
 450                 spin_unlock(&OCFS2_I(dir)->ip_lock);
 451                 credits = OCFS2_SIMPLE_DIR_EXTEND_CREDITS;
 452         }
 453
 454         handle = ocfs2_start_trans(osb, credits);
 455         if (IS_ERR(handle)) {
 456                 status = PTR_ERR(handle);
 457                 handle = NULL;
 458                 mlog_errno(status);
 459                 goto bail;
 460         }
 461
 462         status = ocfs2_do_extend_dir(osb->sb, handle, dir, parent_fe_bh,
 463                                      data_ac, meta_ac, &new_bh);
 464         if (status < 0) {
 465                 mlog_errno(status);
 466                 goto bail;
 467         }
 468
 469         ocfs2_set_new_buffer_uptodate(dir, new_bh);
 470
 471         status = ocfs2_journal_access(handle, dir, new_bh,
 472                                       OCFS2_JOURNAL_ACCESS_CREATE);
 473         if (status < 0) {
 474                 mlog_errno(status);
 475                 goto bail;
 476         }
 477         memset(new_bh->b_data, 0, sb->s_blocksize);
 478         de = (struct ocfs2_dir_entry *) new_bh->b_data;
 479         de->inode = 0;
 480         de->rec_len = cpu_to_le16(sb->s_blocksize);
 481         status = ocfs2_journal_dirty(handle, new_bh);
 482         if (status < 0) {
 483                 mlog_errno(status);
 484                 goto bail;
 485         }
 486
 487         dir_i_size += dir->i_sb->s_blocksize;
 488         i_size_write(dir, dir_i_size);
 489         dir->i_blocks = ocfs2_align_bytes_to_sectors(dir_i_size);
 490         status = ocfs2_mark_inode_dirty(handle, dir, parent_fe_bh);
 491         if (status < 0) {
 492                 mlog_errno(status);
 493                 goto bail;
 494         }
 495
 496         *new_de_bh = new_bh;
 497         get_bh(*new_de_bh);
 498 bail:
 499         if (handle)
 500                 ocfs2_commit_trans(osb, handle);
 501
 502         if (data_ac)
 503                 ocfs2_free_alloc_context(data_ac);
 504         if (meta_ac)
 505                 ocfs2_free_alloc_context(meta_ac);
 506
 507         if (new_bh)
 508                 brelse(new_bh);
 509
 510         mlog_exit(status);
 511         return status;
 512 }
 513
 514 /*
 515  * Search the dir for a good spot, extending it if necessary. The
 516  * block containing an appropriate record is returned in ret_de_bh.
 517  */
 518 int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
 519                                  struct inode *dir,
 520                                  struct buffer_head *parent_fe_bh,
 521                                  const char *name,
 522                                  int namelen,
 523                                  struct buffer_head **ret_de_bh)
 524 {
 525         unsigned long offset;
 526         struct buffer_head * bh = NULL;
 527         unsigned short rec_len;
 528         struct ocfs2_dinode *fe;
 529         struct ocfs2_dir_entry *de;
 530         struct super_block *sb;
 531         int status;
 532
 533         mlog_entry_void();
 534
 535         mlog(0, "getting ready to insert namelen %d into dir %llu\n",
 536              namelen, (unsigned long long)OCFS2_I(dir)->ip_blkno);
 537
 538         BUG_ON(!S_ISDIR(dir->i_mode));
 539         fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
 540         BUG_ON(le64_to_cpu(fe->i_size) != i_size_read(dir));
 541
 542         sb = dir->i_sb;
 543
 544         if (!namelen) {
 545                 status = -EINVAL;
 546                 mlog_errno(status);
 547                 goto bail;
 548         }
 549
 550         bh = ocfs2_bread(dir, 0, &status, 0);
 551         if (!bh) {
 552                 mlog_errno(status);
 553                 goto bail;
 554         }
 555
 556         rec_len = OCFS2_DIR_REC_LEN(namelen);
 557         offset = 0;
 558         de = (struct ocfs2_dir_entry *) bh->b_data;
 559         while (1) {
 560                 if ((char *)de >= sb->s_blocksize + bh->b_data) {
 561                         brelse(bh);
 562                         bh = NULL;
 563
 564                         if (i_size_read(dir) <= offset) {
 565                                 status = ocfs2_extend_dir(osb,
 566                                                           dir,
 567                                                           parent_fe_bh,
 568                                                           &bh);
 569                                 if (status < 0) {
 570                                         mlog_errno(status);
 571                                         goto bail;
 572                                 }
 573                                 BUG_ON(!bh);
 574                                 *ret_de_bh = bh;
 575                                 get_bh(*ret_de_bh);
 576                                 goto bail;
 577                         }
 578                         bh = ocfs2_bread(dir,
 579                                          offset >> sb->s_blocksize_bits,
 580                                          &status,
 581                                          0);
 582                         if (!bh) {
 583                                 mlog_errno(status);
 584                                 goto bail;
 585                         }
 586                         /* move to next block */
 587                         de = (struct ocfs2_dir_entry *) bh->b_data;
 588                 }
 589                 if (!ocfs2_check_dir_entry(dir, de, bh, offset)) {
 590                         status = -ENOENT;
 591                         goto bail;
 592                 }
 593                 if (ocfs2_match(namelen, name, de)) {
 594                         status = -EEXIST;
 595                         goto bail;
 596                 }
 597                 if (((le64_to_cpu(de->inode) == 0) &&
 598                      (le16_to_cpu(de->rec_len) >= rec_len)) ||
 599                     (le16_to_cpu(de->rec_len) >=
 600                      (OCFS2_DIR_REC_LEN(de->name_len) + rec_len))) {
 601                         /* Ok, we found a spot. Return this bh and let
 602                          * the caller actually fill it in. */
 603                         *ret_de_bh = bh;
 604                         get_bh(*ret_de_bh);
 605                         status = 0;
 606                         goto bail;
 607                 }
 608                 offset += le16_to_cpu(de->rec_len);
 609                 de = (struct ocfs2_dir_entry *)((char *) de + le16_to_cpu(de->rec_len));
 610         }
 611
 612         status = 0;
 613 bail:
 614         if (bh)
 615                 brelse(bh);
 616
 617         mlog_exit(status);
 618         return status;
 619 }