fs/ocfs2/resize.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* -*- mode: c; c-basic-offset: 8; -*-
   3  * vim: noexpandtab sw=8 ts=8 sts=0:
   4  *
   5  * resize.c
   6  *
   7  * volume resize.
   8  * Inspired by ext3/resize.c.
   9  *
  10  * Copyright (C) 2007 Oracle.  All rights reserved.
  11  */
  12
  13 #include <linux/fs.h>
  14 #include <linux/types.h>
  15
  16 #include <cluster/masklog.h>
  17
  18 #include "ocfs2.h"
  19
  20 #include "alloc.h"
  21 #include "dlmglue.h"
  22 #include "inode.h"
  23 #include "journal.h"
  24 #include "super.h"
  25 #include "sysfile.h"
  26 #include "uptodate.h"
  27 #include "ocfs2_trace.h"
  28
  29 #include "buffer_head_io.h"
  30 #include "suballoc.h"
  31 #include "resize.h"
  32
  33 /*
  34  * Check whether there are new backup superblocks exist
  35  * in the last group. If there are some, mark them or clear
  36  * them in the bitmap.
  37  *
  38  * Return how many backups we find in the last group.
  39  */
  40 static u16 ocfs2_calc_new_backup_super(struct inode *inode,
  41                                        struct ocfs2_group_desc *gd,
  42                                        u16 cl_cpg,
  43                                        u16 old_bg_clusters,
  44                                        int set)
  45 {
  46         int i;
  47         u16 backups = 0;
  48         u32 cluster, lgd_cluster;
  49         u64 blkno, gd_blkno, lgd_blkno = le64_to_cpu(gd->bg_blkno);
  50
  51         for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
  52                 blkno = ocfs2_backup_super_blkno(inode->i_sb, i);
  53                 cluster = ocfs2_blocks_to_clusters(inode->i_sb, blkno);
  54
  55                 gd_blkno = ocfs2_which_cluster_group(inode, cluster);
  56                 if (gd_blkno < lgd_blkno)
  57                         continue;
  58                 else if (gd_blkno > lgd_blkno)
  59                         break;
  60
  61                 /* check if already done backup super */
  62                 lgd_cluster = ocfs2_blocks_to_clusters(inode->i_sb, lgd_blkno);
  63                 lgd_cluster += old_bg_clusters;
  64                 if (lgd_cluster >= cluster)
  65                         continue;
  66
  67                 if (set)
  68                         ocfs2_set_bit(cluster % cl_cpg,
  69                                       (unsigned long *)gd->bg_bitmap);
  70                 else
  71                         ocfs2_clear_bit(cluster % cl_cpg,
  72                                         (unsigned long *)gd->bg_bitmap);
  73                 backups++;
  74         }
  75
  76         return backups;
  77 }
  78
  79 static int ocfs2_update_last_group_and_inode(handle_t *handle,
  80                                              struct inode *bm_inode,
  81                                              struct buffer_head *bm_bh,
  82                                              struct buffer_head *group_bh,
  83                                              u32 first_new_cluster,
  84                                              int new_clusters)
  85 {
  86         int ret = 0;
  87         struct ocfs2_super *osb = OCFS2_SB(bm_inode->i_sb);
  88         struct ocfs2_dinode *fe = (struct ocfs2_dinode *) bm_bh->b_data;
  89         struct ocfs2_chain_list *cl = &fe->id2.i_chain;
  90         struct ocfs2_chain_rec *cr;
  91         struct ocfs2_group_desc *group;
  92         u16 chain, num_bits, backups = 0;
  93         u16 cl_bpc = le16_to_cpu(cl->cl_bpc);
  94         u16 cl_cpg = le16_to_cpu(cl->cl_cpg);
  95         u16 old_bg_clusters;
  96
  97         trace_ocfs2_update_last_group_and_inode(new_clusters,
  98                                                 first_new_cluster);
  99
 100         ret = ocfs2_journal_access_gd(handle, INODE_CACHE(bm_inode),
 101                                       group_bh, OCFS2_JOURNAL_ACCESS_WRITE);
 102         if (ret < 0) {
 103                 mlog_errno(ret);
 104                 goto out;
 105         }
 106
 107         group = (struct ocfs2_group_desc *)group_bh->b_data;
 108
 109         old_bg_clusters = le16_to_cpu(group->bg_bits) / cl_bpc;
 110         /* update the group first. */
 111         num_bits = new_clusters * cl_bpc;
 112         le16_add_cpu(&group->bg_bits, num_bits);
 113         le16_add_cpu(&group->bg_free_bits_count, num_bits);
 114
 115         /*
 116          * check whether there are some new backup superblocks exist in
 117          * this group and update the group bitmap accordingly.
 118          */
 119         if (OCFS2_HAS_COMPAT_FEATURE(osb->sb,
 120                                      OCFS2_FEATURE_COMPAT_BACKUP_SB)) {
 121                 backups = ocfs2_calc_new_backup_super(bm_inode,
 122                                                      group,
 123                                                      cl_cpg, old_bg_clusters, 1);
 124                 le16_add_cpu(&group->bg_free_bits_count, -1 * backups);
 125         }
 126
 127         ocfs2_journal_dirty(handle, group_bh);
 128
 129         /* update the inode accordingly. */
 130         ret = ocfs2_journal_access_di(handle, INODE_CACHE(bm_inode), bm_bh,
 131                                       OCFS2_JOURNAL_ACCESS_WRITE);
 132         if (ret < 0) {
 133                 mlog_errno(ret);
 134                 goto out_rollback;
 135         }
 136
 137         chain = le16_to_cpu(group->bg_chain);
 138         cr = (&cl->cl_recs[chain]);
 139         le32_add_cpu(&cr->c_total, num_bits);
 140         le32_add_cpu(&cr->c_free, num_bits);
 141         le32_add_cpu(&fe->id1.bitmap1.i_total, num_bits);
 142         le32_add_cpu(&fe->i_clusters, new_clusters);
 143
 144         if (backups) {
 145                 le32_add_cpu(&cr->c_free, -1 * backups);
 146                 le32_add_cpu(&fe->id1.bitmap1.i_used, backups);
 147         }
 148
 149         spin_lock(&OCFS2_I(bm_inode)->ip_lock);
 150         OCFS2_I(bm_inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
 151         le64_add_cpu(&fe->i_size, (u64)new_clusters << osb->s_clustersize_bits);
 152         spin_unlock(&OCFS2_I(bm_inode)->ip_lock);
 153         i_size_write(bm_inode, le64_to_cpu(fe->i_size));
 154
 155         ocfs2_journal_dirty(handle, bm_bh);
 156
 157 out_rollback:
 158         if (ret < 0) {
 159                 ocfs2_calc_new_backup_super(bm_inode,
 160                                             group,
 161                                             cl_cpg, old_bg_clusters, 0);
 162                 le16_add_cpu(&group->bg_free_bits_count, backups);
 163                 le16_add_cpu(&group->bg_bits, -1 * num_bits);
 164                 le16_add_cpu(&group->bg_free_bits_count, -1 * num_bits);
 165         }
 166 out:
 167         if (ret)
 168                 mlog_errno(ret);
 169         return ret;
 170 }
 171
 172 static int update_backups(struct inode * inode, u32 clusters, char *data)
 173 {
 174         int i, ret = 0;
 175         u32 cluster;
 176         u64 blkno;
 177         struct buffer_head *backup = NULL;
 178         struct ocfs2_dinode *backup_di = NULL;
 179         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 180
 181         /* calculate the real backups we need to update. */
 182         for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
 183                 blkno = ocfs2_backup_super_blkno(inode->i_sb, i);
 184                 cluster = ocfs2_blocks_to_clusters(inode->i_sb, blkno);
 185                 if (cluster >= clusters)
 186                         break;
 187
 188                 ret = ocfs2_read_blocks_sync(osb, blkno, 1, &backup);
 189                 if (ret < 0) {
 190                         mlog_errno(ret);
 191                         break;
 192                 }
 193
 194                 memcpy(backup->b_data, data, inode->i_sb->s_blocksize);
 195
 196                 backup_di = (struct ocfs2_dinode *)backup->b_data;
 197                 backup_di->i_blkno = cpu_to_le64(blkno);
 198
 199                 ret = ocfs2_write_super_or_backup(osb, backup);
 200                 brelse(backup);
 201                 backup = NULL;
 202                 if (ret < 0) {
 203                         mlog_errno(ret);
 204                         break;
 205                 }
 206         }
 207
 208         return ret;
 209 }
 210
 211 static void ocfs2_update_super_and_backups(struct inode *inode,
 212                                            int new_clusters)
 213 {
 214         int ret;
 215         u32 clusters = 0;
 216         struct buffer_head *super_bh = NULL;
 217         struct ocfs2_dinode *super_di = NULL;
 218         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 219
 220         /*
 221          * update the superblock last.
 222          * It doesn't matter if the write failed.
 223          */
 224         ret = ocfs2_read_blocks_sync(osb, OCFS2_SUPER_BLOCK_BLKNO, 1,
 225                                      &super_bh);
 226         if (ret < 0) {
 227                 mlog_errno(ret);
 228                 goto out;
 229         }
 230
 231         super_di = (struct ocfs2_dinode *)super_bh->b_data;
 232         le32_add_cpu(&super_di->i_clusters, new_clusters);
 233         clusters = le32_to_cpu(super_di->i_clusters);
 234
 235         ret = ocfs2_write_super_or_backup(osb, super_bh);
 236         if (ret < 0) {
 237                 mlog_errno(ret);
 238                 goto out;
 239         }
 240
 241         if (OCFS2_HAS_COMPAT_FEATURE(osb->sb, OCFS2_FEATURE_COMPAT_BACKUP_SB))
 242                 ret = update_backups(inode, clusters, super_bh->b_data);
 243
 244 out:
 245         brelse(super_bh);
 246         if (ret)
 247                 printk(KERN_WARNING "ocfs2: Failed to update super blocks on %s"
 248                         " during fs resize. This condition is not fatal,"
 249                         " but fsck.ocfs2 should be run to fix it\n",
 250                         osb->dev_str);
 251         return;
 252 }
 253
 254 /*
 255  * Extend the filesystem to the new number of clusters specified.  This entry
 256  * point is only used to extend the current filesystem to the end of the last
 257  * existing group.
 258  */
 259 int ocfs2_group_extend(struct inode * inode, int new_clusters)
 260 {
 261         int ret;
 262         handle_t *handle;
 263         struct buffer_head *main_bm_bh = NULL;
 264         struct buffer_head *group_bh = NULL;
 265         struct inode *main_bm_inode = NULL;
 266         struct ocfs2_dinode *fe = NULL;
 267         struct ocfs2_group_desc *group = NULL;
 268         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 269         u16 cl_bpc;
 270         u32 first_new_cluster;
 271         u64 lgd_blkno;
 272
 273         if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
 274                 return -EROFS;
 275
 276         if (new_clusters < 0)
 277                 return -EINVAL;
 278         else if (new_clusters == 0)
 279                 return 0;
 280
 281         main_bm_inode = ocfs2_get_system_file_inode(osb,
 282                                                     GLOBAL_BITMAP_SYSTEM_INODE,
 283                                                     OCFS2_INVALID_SLOT);
 284         if (!main_bm_inode) {
 285                 ret = -EINVAL;
 286                 mlog_errno(ret);
 287                 goto out;
 288         }
 289
 290         inode_lock(main_bm_inode);
 291
 292         ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
 293         if (ret < 0) {
 294                 mlog_errno(ret);
 295                 goto out_mutex;
 296         }
 297
 298         fe = (struct ocfs2_dinode *)main_bm_bh->b_data;
 299
 300         /* main_bm_bh is validated by inode read inside ocfs2_inode_lock(),
 301          * so any corruption is a code bug. */
 302         BUG_ON(!OCFS2_IS_VALID_DINODE(fe));
 303
 304         if (le16_to_cpu(fe->id2.i_chain.cl_cpg) !=
 305                 ocfs2_group_bitmap_size(osb->sb, 0,
 306                                         osb->s_feature_incompat) * 8) {
 307                 mlog(ML_ERROR, "The disk is too old and small. "
 308                      "Force to do offline resize.");
 309                 ret = -EINVAL;
 310                 goto out_unlock;
 311         }
 312
 313         first_new_cluster = le32_to_cpu(fe->i_clusters);
 314         lgd_blkno = ocfs2_which_cluster_group(main_bm_inode,
 315                                               first_new_cluster - 1);
 316
 317         ret = ocfs2_read_group_descriptor(main_bm_inode, fe, lgd_blkno,
 318                                           &group_bh);
 319         if (ret < 0) {
 320                 mlog_errno(ret);
 321                 goto out_unlock;
 322         }
 323         group = (struct ocfs2_group_desc *)group_bh->b_data;
 324
 325         cl_bpc = le16_to_cpu(fe->id2.i_chain.cl_bpc);
 326         if (le16_to_cpu(group->bg_bits) / cl_bpc + new_clusters >
 327                 le16_to_cpu(fe->id2.i_chain.cl_cpg)) {
 328                 ret = -EINVAL;
 329                 goto out_unlock;
 330         }
 331
 332
 333         trace_ocfs2_group_extend(
 334              (unsigned long long)le64_to_cpu(group->bg_blkno), new_clusters);
 335
 336         handle = ocfs2_start_trans(osb, OCFS2_GROUP_EXTEND_CREDITS);
 337         if (IS_ERR(handle)) {
 338                 mlog_errno(PTR_ERR(handle));
 339                 ret = -EINVAL;
 340                 goto out_unlock;
 341         }
 342
 343         /* update the last group descriptor and inode. */
 344         ret = ocfs2_update_last_group_and_inode(handle, main_bm_inode,
 345                                                 main_bm_bh, group_bh,
 346                                                 first_new_cluster,
 347                                                 new_clusters);
 348         if (ret) {
 349                 mlog_errno(ret);
 350                 goto out_commit;
 351         }
 352
 353         ocfs2_update_super_and_backups(main_bm_inode, new_clusters);
 354
 355 out_commit:
 356         ocfs2_commit_trans(osb, handle);
 357 out_unlock:
 358         brelse(group_bh);
 359         brelse(main_bm_bh);
 360
 361         ocfs2_inode_unlock(main_bm_inode, 1);
 362
 363 out_mutex:
 364         inode_unlock(main_bm_inode);
 365         iput(main_bm_inode);
 366
 367 out:
 368         return ret;
 369 }
 370
 371 static int ocfs2_check_new_group(struct inode *inode,
 372                                  struct ocfs2_dinode *di,
 373                                  struct ocfs2_new_group_input *input,
 374                                  struct buffer_head *group_bh)
 375 {
 376         int ret;
 377         struct ocfs2_group_desc *gd =
 378                 (struct ocfs2_group_desc *)group_bh->b_data;
 379         u16 cl_bpc = le16_to_cpu(di->id2.i_chain.cl_bpc);
 380
 381         ret = ocfs2_check_group_descriptor(inode->i_sb, di, group_bh);
 382         if (ret)
 383                 goto out;
 384
 385         ret = -EINVAL;
 386         if (le16_to_cpu(gd->bg_chain) != input->chain)
 387                 mlog(ML_ERROR, "Group descriptor # %llu has bad chain %u "
 388                      "while input has %u set.\n",
 389                      (unsigned long long)le64_to_cpu(gd->bg_blkno),
 390                      le16_to_cpu(gd->bg_chain), input->chain);
 391         else if (le16_to_cpu(gd->bg_bits) != input->clusters * cl_bpc)
 392                 mlog(ML_ERROR, "Group descriptor # %llu has bit count %u but "
 393                      "input has %u clusters set\n",
 394                      (unsigned long long)le64_to_cpu(gd->bg_blkno),
 395                      le16_to_cpu(gd->bg_bits), input->clusters);
 396         else if (le16_to_cpu(gd->bg_free_bits_count) != input->frees * cl_bpc)
 397                 mlog(ML_ERROR, "Group descriptor # %llu has free bit count %u "
 398                      "but it should have %u set\n",
 399                      (unsigned long long)le64_to_cpu(gd->bg_blkno),
 400                      le16_to_cpu(gd->bg_bits),
 401                      input->frees * cl_bpc);
 402         else
 403                 ret = 0;
 404
 405 out:
 406         return ret;
 407 }
 408
 409 static int ocfs2_verify_group_and_input(struct inode *inode,
 410                                         struct ocfs2_dinode *di,
 411                                         struct ocfs2_new_group_input *input,
 412                                         struct buffer_head *group_bh)
 413 {
 414         u16 cl_count = le16_to_cpu(di->id2.i_chain.cl_count);
 415         u16 cl_cpg = le16_to_cpu(di->id2.i_chain.cl_cpg);
 416         u16 next_free = le16_to_cpu(di->id2.i_chain.cl_next_free_rec);
 417         u32 cluster = ocfs2_blocks_to_clusters(inode->i_sb, input->group);
 418         u32 total_clusters = le32_to_cpu(di->i_clusters);
 419         int ret = -EINVAL;
 420
 421         if (cluster < total_clusters)
 422                 mlog(ML_ERROR, "add a group which is in the current volume.\n");
 423         else if (input->chain >= cl_count)
 424                 mlog(ML_ERROR, "input chain exceeds the limit.\n");
 425         else if (next_free != cl_count && next_free != input->chain)
 426                 mlog(ML_ERROR,
 427                      "the add group should be in chain %u\n", next_free);
 428         else if (total_clusters + input->clusters < total_clusters)
 429                 mlog(ML_ERROR, "add group's clusters overflow.\n");
 430         else if (input->clusters > cl_cpg)
 431                 mlog(ML_ERROR, "the cluster exceeds the maximum of a group\n");
 432         else if (input->frees > input->clusters)
 433                 mlog(ML_ERROR, "the free cluster exceeds the total clusters\n");
 434         else if (total_clusters % cl_cpg != 0)
 435                 mlog(ML_ERROR,
 436                      "the last group isn't full. Use group extend first.\n");
 437         else if (input->group != ocfs2_which_cluster_group(inode, cluster))
 438                 mlog(ML_ERROR, "group blkno is invalid\n");
 439         else if ((ret = ocfs2_check_new_group(inode, di, input, group_bh)))
 440                 mlog(ML_ERROR, "group descriptor check failed.\n");
 441         else
 442                 ret = 0;
 443
 444         return ret;
 445 }
 446
 447 /* Add a new group descriptor to global_bitmap. */
 448 int ocfs2_group_add(struct inode *inode, struct ocfs2_new_group_input *input)
 449 {
 450         int ret;
 451         handle_t *handle;
 452         struct buffer_head *main_bm_bh = NULL;
 453         struct inode *main_bm_inode = NULL;
 454         struct ocfs2_dinode *fe = NULL;
 455         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 456         struct buffer_head *group_bh = NULL;
 457         struct ocfs2_group_desc *group = NULL;
 458         struct ocfs2_chain_list *cl;
 459         struct ocfs2_chain_rec *cr;
 460         u16 cl_bpc;
 461         u64 bg_ptr;
 462
 463         if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
 464                 return -EROFS;
 465
 466         main_bm_inode = ocfs2_get_system_file_inode(osb,
 467                                                     GLOBAL_BITMAP_SYSTEM_INODE,
 468                                                     OCFS2_INVALID_SLOT);
 469         if (!main_bm_inode) {
 470                 ret = -EINVAL;
 471                 mlog_errno(ret);
 472                 goto out;
 473         }
 474
 475         inode_lock(main_bm_inode);
 476
 477         ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
 478         if (ret < 0) {
 479                 mlog_errno(ret);
 480                 goto out_mutex;
 481         }
 482
 483         fe = (struct ocfs2_dinode *)main_bm_bh->b_data;
 484
 485         if (le16_to_cpu(fe->id2.i_chain.cl_cpg) !=
 486                 ocfs2_group_bitmap_size(osb->sb, 0,
 487                                         osb->s_feature_incompat) * 8) {
 488                 mlog(ML_ERROR, "The disk is too old and small."
 489                      " Force to do offline resize.");
 490                 ret = -EINVAL;
 491                 goto out_unlock;
 492         }
 493
 494         ret = ocfs2_read_blocks_sync(osb, input->group, 1, &group_bh);
 495         if (ret < 0) {
 496                 mlog(ML_ERROR, "Can't read the group descriptor # %llu "
 497                      "from the device.", (unsigned long long)input->group);
 498                 goto out_unlock;
 499         }
 500
 501         ocfs2_set_new_buffer_uptodate(INODE_CACHE(inode), group_bh);
 502
 503         ret = ocfs2_verify_group_and_input(main_bm_inode, fe, input, group_bh);
 504         if (ret) {
 505                 mlog_errno(ret);
 506                 goto out_free_group_bh;
 507         }
 508
 509         trace_ocfs2_group_add((unsigned long long)input->group,
 510                                input->chain, input->clusters, input->frees);
 511
 512         handle = ocfs2_start_trans(osb, OCFS2_GROUP_ADD_CREDITS);
 513         if (IS_ERR(handle)) {
 514                 mlog_errno(PTR_ERR(handle));
 515                 ret = -EINVAL;
 516                 goto out_free_group_bh;
 517         }
 518
 519         cl_bpc = le16_to_cpu(fe->id2.i_chain.cl_bpc);
 520         cl = &fe->id2.i_chain;
 521         cr = &cl->cl_recs[input->chain];
 522
 523         ret = ocfs2_journal_access_gd(handle, INODE_CACHE(main_bm_inode),
 524                                       group_bh, OCFS2_JOURNAL_ACCESS_WRITE);
 525         if (ret < 0) {
 526                 mlog_errno(ret);
 527                 goto out_commit;
 528         }
 529
 530         group = (struct ocfs2_group_desc *)group_bh->b_data;
 531         bg_ptr = le64_to_cpu(group->bg_next_group);
 532         group->bg_next_group = cr->c_blkno;
 533         ocfs2_journal_dirty(handle, group_bh);
 534
 535         ret = ocfs2_journal_access_di(handle, INODE_CACHE(main_bm_inode),
 536                                       main_bm_bh, OCFS2_JOURNAL_ACCESS_WRITE);
 537         if (ret < 0) {
 538                 group->bg_next_group = cpu_to_le64(bg_ptr);
 539                 mlog_errno(ret);
 540                 goto out_commit;
 541         }
 542
 543         if (input->chain == le16_to_cpu(cl->cl_next_free_rec)) {
 544                 le16_add_cpu(&cl->cl_next_free_rec, 1);
 545                 memset(cr, 0, sizeof(struct ocfs2_chain_rec));
 546         }
 547
 548         cr->c_blkno = cpu_to_le64(input->group);
 549         le32_add_cpu(&cr->c_total, input->clusters * cl_bpc);
 550         le32_add_cpu(&cr->c_free, input->frees * cl_bpc);
 551
 552         le32_add_cpu(&fe->id1.bitmap1.i_total, input->clusters *cl_bpc);
 553         le32_add_cpu(&fe->id1.bitmap1.i_used,
 554                      (input->clusters - input->frees) * cl_bpc);
 555         le32_add_cpu(&fe->i_clusters, input->clusters);
 556
 557         ocfs2_journal_dirty(handle, main_bm_bh);
 558
 559         spin_lock(&OCFS2_I(main_bm_inode)->ip_lock);
 560         OCFS2_I(main_bm_inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
 561         le64_add_cpu(&fe->i_size, (u64)input->clusters << osb->s_clustersize_bits);
 562         spin_unlock(&OCFS2_I(main_bm_inode)->ip_lock);
 563         i_size_write(main_bm_inode, le64_to_cpu(fe->i_size));
 564
 565         ocfs2_update_super_and_backups(main_bm_inode, input->clusters);
 566
 567 out_commit:
 568         ocfs2_commit_trans(osb, handle);
 569
 570 out_free_group_bh:
 571         brelse(group_bh);
 572
 573 out_unlock:
 574         brelse(main_bm_bh);
 575
 576         ocfs2_inode_unlock(main_bm_inode, 1);
 577
 578 out_mutex:
 579         inode_unlock(main_bm_inode);
 580         iput(main_bm_inode);
 581
 582 out:
 583         return ret;
 584 }