fs/f2fs/debug.c

   1 /*
   2  * f2fs debugging statistics
   3  *
   4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5  *             http://www.samsung.com/
   6  * Copyright (c) 2012 Linux Foundation
   7  * Copyright (c) 2012 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/fs.h>
  15 #include <linux/backing-dev.h>
  16 #include <linux/f2fs_fs.h>
  17 #include <linux/blkdev.h>
  18 #include <linux/debugfs.h>
  19 #include <linux/seq_file.h>
  20
  21 #include "f2fs.h"
  22 #include "node.h"
  23 #include "segment.h"
  24 #include "gc.h"
  25
  26 static LIST_HEAD(f2fs_stat_list);
  27 static struct dentry *f2fs_debugfs_root;
  28 static DEFINE_MUTEX(f2fs_stat_mutex);
  29
  30 static void update_general_status(struct f2fs_sb_info *sbi)
  31 {
  32         struct f2fs_stat_info *si = F2FS_STAT(sbi);
  33         int i;
  34
  35         /* validation check of the segment numbers */
  36         si->hit_largest = atomic64_read(&sbi->read_hit_largest);
  37         si->hit_cached = atomic64_read(&sbi->read_hit_cached);
  38         si->hit_rbtree = atomic64_read(&sbi->read_hit_rbtree);
  39         si->hit_total = si->hit_largest + si->hit_cached + si->hit_rbtree;
  40         si->total_ext = atomic64_read(&sbi->total_hit_ext);
  41         si->ext_tree = atomic_read(&sbi->total_ext_tree);
  42         si->zombie_tree = atomic_read(&sbi->total_zombie_tree);
  43         si->ext_node = atomic_read(&sbi->total_ext_node);
  44         si->ndirty_node = get_pages(sbi, F2FS_DIRTY_NODES);
  45         si->ndirty_dent = get_pages(sbi, F2FS_DIRTY_DENTS);
  46         si->ndirty_meta = get_pages(sbi, F2FS_DIRTY_META);
  47         si->ndirty_data = get_pages(sbi, F2FS_DIRTY_DATA);
  48         si->ndirty_imeta = get_pages(sbi, F2FS_DIRTY_IMETA);
  49         si->ndirty_dirs = sbi->ndirty_inode[DIR_INODE];
  50         si->ndirty_files = sbi->ndirty_inode[FILE_INODE];
  51         si->ndirty_all = sbi->ndirty_inode[DIRTY_META];
  52         si->inmem_pages = get_pages(sbi, F2FS_INMEM_PAGES);
  53         si->aw_cnt = atomic_read(&sbi->aw_cnt);
  54         si->max_aw_cnt = atomic_read(&sbi->max_aw_cnt);
  55         si->nr_wb_cp_data = get_pages(sbi, F2FS_WB_CP_DATA);
  56         si->nr_wb_data = get_pages(sbi, F2FS_WB_DATA);
  57         if (SM_I(sbi) && SM_I(sbi)->fcc_info)
  58                 si->nr_flush =
  59                         atomic_read(&SM_I(sbi)->fcc_info->submit_flush);
  60         if (SM_I(sbi) && SM_I(sbi)->dcc_info)
  61                 si->nr_discard =
  62                         atomic_read(&SM_I(sbi)->dcc_info->submit_discard);
  63         si->total_count = (int)sbi->user_block_count / sbi->blocks_per_seg;
  64         si->rsvd_segs = reserved_segments(sbi);
  65         si->overp_segs = overprovision_segments(sbi);
  66         si->valid_count = valid_user_blocks(sbi);
  67         si->discard_blks = discard_blocks(sbi);
  68         si->valid_node_count = valid_node_count(sbi);
  69         si->valid_inode_count = valid_inode_count(sbi);
  70         si->inline_xattr = atomic_read(&sbi->inline_xattr);
  71         si->inline_inode = atomic_read(&sbi->inline_inode);
  72         si->inline_dir = atomic_read(&sbi->inline_dir);
  73         si->append = sbi->im[APPEND_INO].ino_num;
  74         si->update = sbi->im[UPDATE_INO].ino_num;
  75         si->orphans = sbi->im[ORPHAN_INO].ino_num;
  76         si->utilization = utilization(sbi);
  77
  78         si->free_segs = free_segments(sbi);
  79         si->free_secs = free_sections(sbi);
  80         si->prefree_count = prefree_segments(sbi);
  81         si->dirty_count = dirty_segments(sbi);
  82         si->node_pages = NODE_MAPPING(sbi)->nrpages;
  83         si->meta_pages = META_MAPPING(sbi)->nrpages;
  84         si->nats = NM_I(sbi)->nat_cnt;
  85         si->dirty_nats = NM_I(sbi)->dirty_nat_cnt;
  86         si->sits = MAIN_SEGS(sbi);
  87         si->dirty_sits = SIT_I(sbi)->dirty_sentries;
  88         si->free_nids = NM_I(sbi)->nid_cnt[FREE_NID_LIST];
  89         si->alloc_nids = NM_I(sbi)->nid_cnt[ALLOC_NID_LIST];
  90         si->bg_gc = sbi->bg_gc;
  91         si->util_free = (int)(free_user_blocks(sbi) >> sbi->log_blocks_per_seg)
  92                 * 100 / (int)(sbi->user_block_count >> sbi->log_blocks_per_seg)
  93                 / 2;
  94         si->util_valid = (int)(written_block_count(sbi) >>
  95                                                 sbi->log_blocks_per_seg)
  96                 * 100 / (int)(sbi->user_block_count >> sbi->log_blocks_per_seg)
  97                 / 2;
  98         si->util_invalid = 50 - si->util_free - si->util_valid;
  99         for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_NODE; i++) {
 100                 struct curseg_info *curseg = CURSEG_I(sbi, i);
 101                 si->curseg[i] = curseg->segno;
 102                 si->cursec[i] = curseg->segno / sbi->segs_per_sec;
 103                 si->curzone[i] = si->cursec[i] / sbi->secs_per_zone;
 104         }
 105
 106         for (i = 0; i < 2; i++) {
 107                 si->segment_count[i] = sbi->segment_count[i];
 108                 si->block_count[i] = sbi->block_count[i];
 109         }
 110
 111         si->inplace_count = atomic_read(&sbi->inplace_count);
 112 }
 113
 114 /*
 115  * This function calculates BDF of every segments
 116  */
 117 static void update_sit_info(struct f2fs_sb_info *sbi)
 118 {
 119         struct f2fs_stat_info *si = F2FS_STAT(sbi);
 120         unsigned long long blks_per_sec, hblks_per_sec, total_vblocks;
 121         unsigned long long bimodal, dist;
 122         unsigned int segno, vblocks;
 123         int ndirty = 0;
 124
 125         bimodal = 0;
 126         total_vblocks = 0;
 127         blks_per_sec = sbi->segs_per_sec * sbi->blocks_per_seg;
 128         hblks_per_sec = blks_per_sec / 2;
 129         for (segno = 0; segno < MAIN_SEGS(sbi); segno += sbi->segs_per_sec) {
 130                 vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 131                 dist = abs(vblocks - hblks_per_sec);
 132                 bimodal += dist * dist;
 133
 134                 if (vblocks > 0 && vblocks < blks_per_sec) {
 135                         total_vblocks += vblocks;
 136                         ndirty++;
 137                 }
 138         }
 139         dist = div_u64(MAIN_SECS(sbi) * hblks_per_sec * hblks_per_sec, 100);
 140         si->bimodal = div64_u64(bimodal, dist);
 141         if (si->dirty_count)
 142                 si->avg_vblocks = div_u64(total_vblocks, ndirty);
 143         else
 144                 si->avg_vblocks = 0;
 145 }
 146
 147 /*
 148  * This function calculates memory footprint.
 149  */
 150 static void update_mem_info(struct f2fs_sb_info *sbi)
 151 {
 152         struct f2fs_stat_info *si = F2FS_STAT(sbi);
 153         unsigned npages;
 154         int i;
 155
 156         if (si->base_mem)
 157                 goto get_cache;
 158
 159         si->base_mem = sizeof(struct f2fs_sb_info) + sbi->sb->s_blocksize;
 160         si->base_mem += 2 * sizeof(struct f2fs_inode_info);
 161         si->base_mem += sizeof(*sbi->ckpt);
 162         si->base_mem += sizeof(struct percpu_counter) * NR_COUNT_TYPE;
 163
 164         /* build sm */
 165         si->base_mem += sizeof(struct f2fs_sm_info);
 166
 167         /* build sit */
 168         si->base_mem += sizeof(struct sit_info);
 169         si->base_mem += MAIN_SEGS(sbi) * sizeof(struct seg_entry);
 170         si->base_mem += f2fs_bitmap_size(MAIN_SEGS(sbi));
 171         si->base_mem += 2 * SIT_VBLOCK_MAP_SIZE * MAIN_SEGS(sbi);
 172         if (f2fs_discard_en(sbi))
 173                 si->base_mem += SIT_VBLOCK_MAP_SIZE * MAIN_SEGS(sbi);
 174         si->base_mem += SIT_VBLOCK_MAP_SIZE;
 175         if (sbi->segs_per_sec > 1)
 176                 si->base_mem += MAIN_SECS(sbi) * sizeof(struct sec_entry);
 177         si->base_mem += __bitmap_size(sbi, SIT_BITMAP);
 178
 179         /* build free segmap */
 180         si->base_mem += sizeof(struct free_segmap_info);
 181         si->base_mem += f2fs_bitmap_size(MAIN_SEGS(sbi));
 182         si->base_mem += f2fs_bitmap_size(MAIN_SECS(sbi));
 183
 184         /* build curseg */
 185         si->base_mem += sizeof(struct curseg_info) * NR_CURSEG_TYPE;
 186         si->base_mem += PAGE_SIZE * NR_CURSEG_TYPE;
 187
 188         /* build dirty segmap */
 189         si->base_mem += sizeof(struct dirty_seglist_info);
 190         si->base_mem += NR_DIRTY_TYPE * f2fs_bitmap_size(MAIN_SEGS(sbi));
 191         si->base_mem += f2fs_bitmap_size(MAIN_SECS(sbi));
 192
 193         /* build nm */
 194         si->base_mem += sizeof(struct f2fs_nm_info);
 195         si->base_mem += __bitmap_size(sbi, NAT_BITMAP);
 196         si->base_mem += (NM_I(sbi)->nat_bits_blocks << F2FS_BLKSIZE_BITS);
 197         si->base_mem += NM_I(sbi)->nat_blocks * NAT_ENTRY_BITMAP_SIZE;
 198         si->base_mem += NM_I(sbi)->nat_blocks / 8;
 199
 200 get_cache:
 201         si->cache_mem = 0;
 202
 203         /* build gc */
 204         if (sbi->gc_thread)
 205                 si->cache_mem += sizeof(struct f2fs_gc_kthread);
 206
 207         /* build merge flush thread */
 208         if (SM_I(sbi)->fcc_info)
 209                 si->cache_mem += sizeof(struct flush_cmd_control);
 210         if (SM_I(sbi)->dcc_info)
 211                 si->cache_mem += sizeof(struct discard_cmd_control);
 212
 213         /* free nids */
 214         si->cache_mem += (NM_I(sbi)->nid_cnt[FREE_NID_LIST] +
 215                                 NM_I(sbi)->nid_cnt[ALLOC_NID_LIST]) *
 216                                 sizeof(struct free_nid);
 217         si->cache_mem += NM_I(sbi)->nat_cnt * sizeof(struct nat_entry);
 218         si->cache_mem += NM_I(sbi)->dirty_nat_cnt *
 219                                         sizeof(struct nat_entry_set);
 220         si->cache_mem += si->inmem_pages * sizeof(struct inmem_pages);
 221         for (i = 0; i <= ORPHAN_INO; i++)
 222                 si->cache_mem += sbi->im[i].ino_num * sizeof(struct ino_entry);
 223         si->cache_mem += atomic_read(&sbi->total_ext_tree) *
 224                                                 sizeof(struct extent_tree);
 225         si->cache_mem += atomic_read(&sbi->total_ext_node) *
 226                                                 sizeof(struct extent_node);
 227
 228         si->page_mem = 0;
 229         npages = NODE_MAPPING(sbi)->nrpages;
 230         si->page_mem += (unsigned long long)npages << PAGE_SHIFT;
 231         npages = META_MAPPING(sbi)->nrpages;
 232         si->page_mem += (unsigned long long)npages << PAGE_SHIFT;
 233 }
 234
 235 static int stat_show(struct seq_file *s, void *v)
 236 {
 237         struct f2fs_stat_info *si;
 238         int i = 0;
 239         int j;
 240
 241         mutex_lock(&f2fs_stat_mutex);
 242         list_for_each_entry(si, &f2fs_stat_list, stat_list) {
 243                 update_general_status(si->sbi);
 244
 245                 seq_printf(s, "\n=====[ partition info(%pg). #%d, %s]=====\n",
 246                         si->sbi->sb->s_bdev, i++,
 247                         f2fs_readonly(si->sbi->sb) ? "RO": "RW");
 248                 seq_printf(s, "[SB: 1] [CP: 2] [SIT: %d] [NAT: %d] ",
 249                            si->sit_area_segs, si->nat_area_segs);
 250                 seq_printf(s, "[SSA: %d] [MAIN: %d",
 251                            si->ssa_area_segs, si->main_area_segs);
 252                 seq_printf(s, "(OverProv:%d Resv:%d)]\n\n",
 253                            si->overp_segs, si->rsvd_segs);
 254                 if (test_opt(si->sbi, DISCARD))
 255                         seq_printf(s, "Utilization: %u%% (%u valid blocks, %u discard blocks)\n",
 256                                 si->utilization, si->valid_count, si->discard_blks);
 257                 else
 258                         seq_printf(s, "Utilization: %u%% (%u valid blocks)\n",
 259                                 si->utilization, si->valid_count);
 260
 261                 seq_printf(s, "  - Node: %u (Inode: %u, ",
 262                            si->valid_node_count, si->valid_inode_count);
 263                 seq_printf(s, "Other: %u)\n  - Data: %u\n",
 264                            si->valid_node_count - si->valid_inode_count,
 265                            si->valid_count - si->valid_node_count);
 266                 seq_printf(s, "  - Inline_xattr Inode: %u\n",
 267                            si->inline_xattr);
 268                 seq_printf(s, "  - Inline_data Inode: %u\n",
 269                            si->inline_inode);
 270                 seq_printf(s, "  - Inline_dentry Inode: %u\n",
 271                            si->inline_dir);
 272                 seq_printf(s, "  - Orphan/Append/Update Inode: %u, %u, %u\n",
 273                            si->orphans, si->append, si->update);
 274                 seq_printf(s, "\nMain area: %d segs, %d secs %d zones\n",
 275                            si->main_area_segs, si->main_area_sections,
 276                            si->main_area_zones);
 277                 seq_printf(s, "  - COLD  data: %d, %d, %d\n",
 278                            si->curseg[CURSEG_COLD_DATA],
 279                            si->cursec[CURSEG_COLD_DATA],
 280                            si->curzone[CURSEG_COLD_DATA]);
 281                 seq_printf(s, "  - WARM  data: %d, %d, %d\n",
 282                            si->curseg[CURSEG_WARM_DATA],
 283                            si->cursec[CURSEG_WARM_DATA],
 284                            si->curzone[CURSEG_WARM_DATA]);
 285                 seq_printf(s, "  - HOT   data: %d, %d, %d\n",
 286                            si->curseg[CURSEG_HOT_DATA],
 287                            si->cursec[CURSEG_HOT_DATA],
 288                            si->curzone[CURSEG_HOT_DATA]);
 289                 seq_printf(s, "  - Dir   dnode: %d, %d, %d\n",
 290                            si->curseg[CURSEG_HOT_NODE],
 291                            si->cursec[CURSEG_HOT_NODE],
 292                            si->curzone[CURSEG_HOT_NODE]);
 293                 seq_printf(s, "  - File   dnode: %d, %d, %d\n",
 294                            si->curseg[CURSEG_WARM_NODE],
 295                            si->cursec[CURSEG_WARM_NODE],
 296                            si->curzone[CURSEG_WARM_NODE]);
 297                 seq_printf(s, "  - Indir nodes: %d, %d, %d\n",
 298                            si->curseg[CURSEG_COLD_NODE],
 299                            si->cursec[CURSEG_COLD_NODE],
 300                            si->curzone[CURSEG_COLD_NODE]);
 301                 seq_printf(s, "\n  - Valid: %d\n  - Dirty: %d\n",
 302                            si->main_area_segs - si->dirty_count -
 303                            si->prefree_count - si->free_segs,
 304                            si->dirty_count);
 305                 seq_printf(s, "  - Prefree: %d\n  - Free: %d (%d)\n\n",
 306                            si->prefree_count, si->free_segs, si->free_secs);
 307                 seq_printf(s, "CP calls: %d (BG: %d)\n",
 308                                 si->cp_count, si->bg_cp_count);
 309                 seq_printf(s, "GC calls: %d (BG: %d)\n",
 310                            si->call_count, si->bg_gc);
 311                 seq_printf(s, "  - data segments : %d (%d)\n",
 312                                 si->data_segs, si->bg_data_segs);
 313                 seq_printf(s, "  - node segments : %d (%d)\n",
 314                                 si->node_segs, si->bg_node_segs);
 315                 seq_printf(s, "Try to move %d blocks (BG: %d)\n", si->tot_blks,
 316                                 si->bg_data_blks + si->bg_node_blks);
 317                 seq_printf(s, "  - data blocks : %d (%d)\n", si->data_blks,
 318                                 si->bg_data_blks);
 319                 seq_printf(s, "  - node blocks : %d (%d)\n", si->node_blks,
 320                                 si->bg_node_blks);
 321                 seq_puts(s, "\nExtent Cache:\n");
 322                 seq_printf(s, "  - Hit Count: L1-1:%llu L1-2:%llu L2:%llu\n",
 323                                 si->hit_largest, si->hit_cached,
 324                                 si->hit_rbtree);
 325                 seq_printf(s, "  - Hit Ratio: %llu%% (%llu / %llu)\n",
 326                                 !si->total_ext ? 0 :
 327                                 div64_u64(si->hit_total * 100, si->total_ext),
 328                                 si->hit_total, si->total_ext);
 329                 seq_printf(s, "  - Inner Struct Count: tree: %d(%d), node: %d\n",
 330                                 si->ext_tree, si->zombie_tree, si->ext_node);
 331                 seq_puts(s, "\nBalancing F2FS Async:\n");
 332                 seq_printf(s, "  - IO (CP: %4d, Data: %4d, Flush: %4d, Discard: %4d)\n",
 333                            si->nr_wb_cp_data, si->nr_wb_data,
 334                            si->nr_flush, si->nr_discard);
 335                 seq_printf(s, "  - inmem: %4d, atomic IO: %4d (Max. %4d)\n",
 336                            si->inmem_pages, si->aw_cnt, si->max_aw_cnt);
 337                 seq_printf(s, "  - nodes: %4d in %4d\n",
 338                            si->ndirty_node, si->node_pages);
 339                 seq_printf(s, "  - dents: %4d in dirs:%4d (%4d)\n",
 340                            si->ndirty_dent, si->ndirty_dirs, si->ndirty_all);
 341                 seq_printf(s, "  - datas: %4d in files:%4d\n",
 342                            si->ndirty_data, si->ndirty_files);
 343                 seq_printf(s, "  - meta: %4d in %4d\n",
 344                            si->ndirty_meta, si->meta_pages);
 345                 seq_printf(s, "  - imeta: %4d\n",
 346                            si->ndirty_imeta);
 347                 seq_printf(s, "  - NATs: %9d/%9d\n  - SITs: %9d/%9d\n",
 348                            si->dirty_nats, si->nats, si->dirty_sits, si->sits);
 349                 seq_printf(s, "  - free_nids: %9d, alloc_nids: %9d\n",
 350                            si->free_nids, si->alloc_nids);
 351                 seq_puts(s, "\nDistribution of User Blocks:");
 352                 seq_puts(s, " [ valid | invalid | free ]\n");
 353                 seq_puts(s, "  [");
 354
 355                 for (j = 0; j < si->util_valid; j++)
 356                         seq_putc(s, '-');
 357                 seq_putc(s, '|');
 358
 359                 for (j = 0; j < si->util_invalid; j++)
 360                         seq_putc(s, '-');
 361                 seq_putc(s, '|');
 362
 363                 for (j = 0; j < si->util_free; j++)
 364                         seq_putc(s, '-');
 365                 seq_puts(s, "]\n\n");
 366                 seq_printf(s, "IPU: %u blocks\n", si->inplace_count);
 367                 seq_printf(s, "SSR: %u blocks in %u segments\n",
 368                            si->block_count[SSR], si->segment_count[SSR]);
 369                 seq_printf(s, "LFS: %u blocks in %u segments\n",
 370                            si->block_count[LFS], si->segment_count[LFS]);
 371
 372                 /* segment usage info */
 373                 update_sit_info(si->sbi);
 374                 seq_printf(s, "\nBDF: %u, avg. vblocks: %u\n",
 375                            si->bimodal, si->avg_vblocks);
 376
 377                 /* memory footprint */
 378                 update_mem_info(si->sbi);
 379                 seq_printf(s, "\nMemory: %llu KB\n",
 380                         (si->base_mem + si->cache_mem + si->page_mem) >> 10);
 381                 seq_printf(s, "  - static: %llu KB\n",
 382                                 si->base_mem >> 10);
 383                 seq_printf(s, "  - cached: %llu KB\n",
 384                                 si->cache_mem >> 10);
 385                 seq_printf(s, "  - paged : %llu KB\n",
 386                                 si->page_mem >> 10);
 387         }
 388         mutex_unlock(&f2fs_stat_mutex);
 389         return 0;
 390 }
 391
 392 static int stat_open(struct inode *inode, struct file *file)
 393 {
 394         return single_open(file, stat_show, inode->i_private);
 395 }
 396
 397 static const struct file_operations stat_fops = {
 398         .owner = THIS_MODULE,
 399         .open = stat_open,
 400         .read = seq_read,
 401         .llseek = seq_lseek,
 402         .release = single_release,
 403 };
 404
 405 int f2fs_build_stats(struct f2fs_sb_info *sbi)
 406 {
 407         struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
 408         struct f2fs_stat_info *si;
 409
 410         si = kzalloc(sizeof(struct f2fs_stat_info), GFP_KERNEL);
 411         if (!si)
 412                 return -ENOMEM;
 413
 414         si->all_area_segs = le32_to_cpu(raw_super->segment_count);
 415         si->sit_area_segs = le32_to_cpu(raw_super->segment_count_sit);
 416         si->nat_area_segs = le32_to_cpu(raw_super->segment_count_nat);
 417         si->ssa_area_segs = le32_to_cpu(raw_super->segment_count_ssa);
 418         si->main_area_segs = le32_to_cpu(raw_super->segment_count_main);
 419         si->main_area_sections = le32_to_cpu(raw_super->section_count);
 420         si->main_area_zones = si->main_area_sections /
 421                                 le32_to_cpu(raw_super->secs_per_zone);
 422         si->sbi = sbi;
 423         sbi->stat_info = si;
 424
 425         atomic64_set(&sbi->total_hit_ext, 0);
 426         atomic64_set(&sbi->read_hit_rbtree, 0);
 427         atomic64_set(&sbi->read_hit_largest, 0);
 428         atomic64_set(&sbi->read_hit_cached, 0);
 429
 430         atomic_set(&sbi->inline_xattr, 0);
 431         atomic_set(&sbi->inline_inode, 0);
 432         atomic_set(&sbi->inline_dir, 0);
 433         atomic_set(&sbi->inplace_count, 0);
 434
 435         atomic_set(&sbi->aw_cnt, 0);
 436         atomic_set(&sbi->max_aw_cnt, 0);
 437
 438         mutex_lock(&f2fs_stat_mutex);
 439         list_add_tail(&si->stat_list, &f2fs_stat_list);
 440         mutex_unlock(&f2fs_stat_mutex);
 441
 442         return 0;
 443 }
 444
 445 void f2fs_destroy_stats(struct f2fs_sb_info *sbi)
 446 {
 447         struct f2fs_stat_info *si = F2FS_STAT(sbi);
 448
 449         mutex_lock(&f2fs_stat_mutex);
 450         list_del(&si->stat_list);
 451         mutex_unlock(&f2fs_stat_mutex);
 452
 453         kfree(si);
 454 }
 455
 456 int __init f2fs_create_root_stats(void)
 457 {
 458         struct dentry *file;
 459
 460         f2fs_debugfs_root = debugfs_create_dir("f2fs", NULL);
 461         if (!f2fs_debugfs_root)
 462                 return -ENOMEM;
 463
 464         file = debugfs_create_file("status", S_IRUGO, f2fs_debugfs_root,
 465                         NULL, &stat_fops);
 466         if (!file) {
 467                 debugfs_remove(f2fs_debugfs_root);
 468                 f2fs_debugfs_root = NULL;
 469                 return -ENOMEM;
 470         }
 471
 472         return 0;
 473 }
 474
 475 void f2fs_destroy_root_stats(void)
 476 {
 477         if (!f2fs_debugfs_root)
 478                 return;
 479
 480         debugfs_remove_recursive(f2fs_debugfs_root);
 481         f2fs_debugfs_root = NULL;
 482 }