xref: /openbmc/linux/fs/f2fs/debug.c (revision 1c2dd16a)
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 	si->base_mem += NM_I(sbi)->nat_blocks * sizeof(unsigned short);
200 
201 get_cache:
202 	si->cache_mem = 0;
203 
204 	/* build gc */
205 	if (sbi->gc_thread)
206 		si->cache_mem += sizeof(struct f2fs_gc_kthread);
207 
208 	/* build merge flush thread */
209 	if (SM_I(sbi)->fcc_info)
210 		si->cache_mem += sizeof(struct flush_cmd_control);
211 	if (SM_I(sbi)->dcc_info)
212 		si->cache_mem += sizeof(struct discard_cmd_control);
213 
214 	/* free nids */
215 	si->cache_mem += (NM_I(sbi)->nid_cnt[FREE_NID_LIST] +
216 				NM_I(sbi)->nid_cnt[ALLOC_NID_LIST]) *
217 				sizeof(struct free_nid);
218 	si->cache_mem += NM_I(sbi)->nat_cnt * sizeof(struct nat_entry);
219 	si->cache_mem += NM_I(sbi)->dirty_nat_cnt *
220 					sizeof(struct nat_entry_set);
221 	si->cache_mem += si->inmem_pages * sizeof(struct inmem_pages);
222 	for (i = 0; i <= ORPHAN_INO; i++)
223 		si->cache_mem += sbi->im[i].ino_num * sizeof(struct ino_entry);
224 	si->cache_mem += atomic_read(&sbi->total_ext_tree) *
225 						sizeof(struct extent_tree);
226 	si->cache_mem += atomic_read(&sbi->total_ext_node) *
227 						sizeof(struct extent_node);
228 
229 	si->page_mem = 0;
230 	npages = NODE_MAPPING(sbi)->nrpages;
231 	si->page_mem += (unsigned long long)npages << PAGE_SHIFT;
232 	npages = META_MAPPING(sbi)->nrpages;
233 	si->page_mem += (unsigned long long)npages << PAGE_SHIFT;
234 }
235 
236 static int stat_show(struct seq_file *s, void *v)
237 {
238 	struct f2fs_stat_info *si;
239 	int i = 0;
240 	int j;
241 
242 	mutex_lock(&f2fs_stat_mutex);
243 	list_for_each_entry(si, &f2fs_stat_list, stat_list) {
244 		update_general_status(si->sbi);
245 
246 		seq_printf(s, "\n=====[ partition info(%pg). #%d, %s]=====\n",
247 			si->sbi->sb->s_bdev, i++,
248 			f2fs_readonly(si->sbi->sb) ? "RO": "RW");
249 		seq_printf(s, "[SB: 1] [CP: 2] [SIT: %d] [NAT: %d] ",
250 			   si->sit_area_segs, si->nat_area_segs);
251 		seq_printf(s, "[SSA: %d] [MAIN: %d",
252 			   si->ssa_area_segs, si->main_area_segs);
253 		seq_printf(s, "(OverProv:%d Resv:%d)]\n\n",
254 			   si->overp_segs, si->rsvd_segs);
255 		if (test_opt(si->sbi, DISCARD))
256 			seq_printf(s, "Utilization: %u%% (%u valid blocks, %u discard blocks)\n",
257 				si->utilization, si->valid_count, si->discard_blks);
258 		else
259 			seq_printf(s, "Utilization: %u%% (%u valid blocks)\n",
260 				si->utilization, si->valid_count);
261 
262 		seq_printf(s, "  - Node: %u (Inode: %u, ",
263 			   si->valid_node_count, si->valid_inode_count);
264 		seq_printf(s, "Other: %u)\n  - Data: %u\n",
265 			   si->valid_node_count - si->valid_inode_count,
266 			   si->valid_count - si->valid_node_count);
267 		seq_printf(s, "  - Inline_xattr Inode: %u\n",
268 			   si->inline_xattr);
269 		seq_printf(s, "  - Inline_data Inode: %u\n",
270 			   si->inline_inode);
271 		seq_printf(s, "  - Inline_dentry Inode: %u\n",
272 			   si->inline_dir);
273 		seq_printf(s, "  - Orphan/Append/Update Inode: %u, %u, %u\n",
274 			   si->orphans, si->append, si->update);
275 		seq_printf(s, "\nMain area: %d segs, %d secs %d zones\n",
276 			   si->main_area_segs, si->main_area_sections,
277 			   si->main_area_zones);
278 		seq_printf(s, "  - COLD  data: %d, %d, %d\n",
279 			   si->curseg[CURSEG_COLD_DATA],
280 			   si->cursec[CURSEG_COLD_DATA],
281 			   si->curzone[CURSEG_COLD_DATA]);
282 		seq_printf(s, "  - WARM  data: %d, %d, %d\n",
283 			   si->curseg[CURSEG_WARM_DATA],
284 			   si->cursec[CURSEG_WARM_DATA],
285 			   si->curzone[CURSEG_WARM_DATA]);
286 		seq_printf(s, "  - HOT   data: %d, %d, %d\n",
287 			   si->curseg[CURSEG_HOT_DATA],
288 			   si->cursec[CURSEG_HOT_DATA],
289 			   si->curzone[CURSEG_HOT_DATA]);
290 		seq_printf(s, "  - Dir   dnode: %d, %d, %d\n",
291 			   si->curseg[CURSEG_HOT_NODE],
292 			   si->cursec[CURSEG_HOT_NODE],
293 			   si->curzone[CURSEG_HOT_NODE]);
294 		seq_printf(s, "  - File   dnode: %d, %d, %d\n",
295 			   si->curseg[CURSEG_WARM_NODE],
296 			   si->cursec[CURSEG_WARM_NODE],
297 			   si->curzone[CURSEG_WARM_NODE]);
298 		seq_printf(s, "  - Indir nodes: %d, %d, %d\n",
299 			   si->curseg[CURSEG_COLD_NODE],
300 			   si->cursec[CURSEG_COLD_NODE],
301 			   si->curzone[CURSEG_COLD_NODE]);
302 		seq_printf(s, "\n  - Valid: %d\n  - Dirty: %d\n",
303 			   si->main_area_segs - si->dirty_count -
304 			   si->prefree_count - si->free_segs,
305 			   si->dirty_count);
306 		seq_printf(s, "  - Prefree: %d\n  - Free: %d (%d)\n\n",
307 			   si->prefree_count, si->free_segs, si->free_secs);
308 		seq_printf(s, "CP calls: %d (BG: %d)\n",
309 				si->cp_count, si->bg_cp_count);
310 		seq_printf(s, "GC calls: %d (BG: %d)\n",
311 			   si->call_count, si->bg_gc);
312 		seq_printf(s, "  - data segments : %d (%d)\n",
313 				si->data_segs, si->bg_data_segs);
314 		seq_printf(s, "  - node segments : %d (%d)\n",
315 				si->node_segs, si->bg_node_segs);
316 		seq_printf(s, "Try to move %d blocks (BG: %d)\n", si->tot_blks,
317 				si->bg_data_blks + si->bg_node_blks);
318 		seq_printf(s, "  - data blocks : %d (%d)\n", si->data_blks,
319 				si->bg_data_blks);
320 		seq_printf(s, "  - node blocks : %d (%d)\n", si->node_blks,
321 				si->bg_node_blks);
322 		seq_puts(s, "\nExtent Cache:\n");
323 		seq_printf(s, "  - Hit Count: L1-1:%llu L1-2:%llu L2:%llu\n",
324 				si->hit_largest, si->hit_cached,
325 				si->hit_rbtree);
326 		seq_printf(s, "  - Hit Ratio: %llu%% (%llu / %llu)\n",
327 				!si->total_ext ? 0 :
328 				div64_u64(si->hit_total * 100, si->total_ext),
329 				si->hit_total, si->total_ext);
330 		seq_printf(s, "  - Inner Struct Count: tree: %d(%d), node: %d\n",
331 				si->ext_tree, si->zombie_tree, si->ext_node);
332 		seq_puts(s, "\nBalancing F2FS Async:\n");
333 		seq_printf(s, "  - IO (CP: %4d, Data: %4d, Flush: %4d, Discard: %4d)\n",
334 			   si->nr_wb_cp_data, si->nr_wb_data,
335 			   si->nr_flush, si->nr_discard);
336 		seq_printf(s, "  - inmem: %4d, atomic IO: %4d (Max. %4d)\n",
337 			   si->inmem_pages, si->aw_cnt, si->max_aw_cnt);
338 		seq_printf(s, "  - nodes: %4d in %4d\n",
339 			   si->ndirty_node, si->node_pages);
340 		seq_printf(s, "  - dents: %4d in dirs:%4d (%4d)\n",
341 			   si->ndirty_dent, si->ndirty_dirs, si->ndirty_all);
342 		seq_printf(s, "  - datas: %4d in files:%4d\n",
343 			   si->ndirty_data, si->ndirty_files);
344 		seq_printf(s, "  - meta: %4d in %4d\n",
345 			   si->ndirty_meta, si->meta_pages);
346 		seq_printf(s, "  - imeta: %4d\n",
347 			   si->ndirty_imeta);
348 		seq_printf(s, "  - NATs: %9d/%9d\n  - SITs: %9d/%9d\n",
349 			   si->dirty_nats, si->nats, si->dirty_sits, si->sits);
350 		seq_printf(s, "  - free_nids: %9d, alloc_nids: %9d\n",
351 			   si->free_nids, si->alloc_nids);
352 		seq_puts(s, "\nDistribution of User Blocks:");
353 		seq_puts(s, " [ valid | invalid | free ]\n");
354 		seq_puts(s, "  [");
355 
356 		for (j = 0; j < si->util_valid; j++)
357 			seq_putc(s, '-');
358 		seq_putc(s, '|');
359 
360 		for (j = 0; j < si->util_invalid; j++)
361 			seq_putc(s, '-');
362 		seq_putc(s, '|');
363 
364 		for (j = 0; j < si->util_free; j++)
365 			seq_putc(s, '-');
366 		seq_puts(s, "]\n\n");
367 		seq_printf(s, "IPU: %u blocks\n", si->inplace_count);
368 		seq_printf(s, "SSR: %u blocks in %u segments\n",
369 			   si->block_count[SSR], si->segment_count[SSR]);
370 		seq_printf(s, "LFS: %u blocks in %u segments\n",
371 			   si->block_count[LFS], si->segment_count[LFS]);
372 
373 		/* segment usage info */
374 		update_sit_info(si->sbi);
375 		seq_printf(s, "\nBDF: %u, avg. vblocks: %u\n",
376 			   si->bimodal, si->avg_vblocks);
377 
378 		/* memory footprint */
379 		update_mem_info(si->sbi);
380 		seq_printf(s, "\nMemory: %llu KB\n",
381 			(si->base_mem + si->cache_mem + si->page_mem) >> 10);
382 		seq_printf(s, "  - static: %llu KB\n",
383 				si->base_mem >> 10);
384 		seq_printf(s, "  - cached: %llu KB\n",
385 				si->cache_mem >> 10);
386 		seq_printf(s, "  - paged : %llu KB\n",
387 				si->page_mem >> 10);
388 	}
389 	mutex_unlock(&f2fs_stat_mutex);
390 	return 0;
391 }
392 
393 static int stat_open(struct inode *inode, struct file *file)
394 {
395 	return single_open(file, stat_show, inode->i_private);
396 }
397 
398 static const struct file_operations stat_fops = {
399 	.owner = THIS_MODULE,
400 	.open = stat_open,
401 	.read = seq_read,
402 	.llseek = seq_lseek,
403 	.release = single_release,
404 };
405 
406 int f2fs_build_stats(struct f2fs_sb_info *sbi)
407 {
408 	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
409 	struct f2fs_stat_info *si;
410 
411 	si = kzalloc(sizeof(struct f2fs_stat_info), GFP_KERNEL);
412 	if (!si)
413 		return -ENOMEM;
414 
415 	si->all_area_segs = le32_to_cpu(raw_super->segment_count);
416 	si->sit_area_segs = le32_to_cpu(raw_super->segment_count_sit);
417 	si->nat_area_segs = le32_to_cpu(raw_super->segment_count_nat);
418 	si->ssa_area_segs = le32_to_cpu(raw_super->segment_count_ssa);
419 	si->main_area_segs = le32_to_cpu(raw_super->segment_count_main);
420 	si->main_area_sections = le32_to_cpu(raw_super->section_count);
421 	si->main_area_zones = si->main_area_sections /
422 				le32_to_cpu(raw_super->secs_per_zone);
423 	si->sbi = sbi;
424 	sbi->stat_info = si;
425 
426 	atomic64_set(&sbi->total_hit_ext, 0);
427 	atomic64_set(&sbi->read_hit_rbtree, 0);
428 	atomic64_set(&sbi->read_hit_largest, 0);
429 	atomic64_set(&sbi->read_hit_cached, 0);
430 
431 	atomic_set(&sbi->inline_xattr, 0);
432 	atomic_set(&sbi->inline_inode, 0);
433 	atomic_set(&sbi->inline_dir, 0);
434 	atomic_set(&sbi->inplace_count, 0);
435 
436 	atomic_set(&sbi->aw_cnt, 0);
437 	atomic_set(&sbi->max_aw_cnt, 0);
438 
439 	mutex_lock(&f2fs_stat_mutex);
440 	list_add_tail(&si->stat_list, &f2fs_stat_list);
441 	mutex_unlock(&f2fs_stat_mutex);
442 
443 	return 0;
444 }
445 
446 void f2fs_destroy_stats(struct f2fs_sb_info *sbi)
447 {
448 	struct f2fs_stat_info *si = F2FS_STAT(sbi);
449 
450 	mutex_lock(&f2fs_stat_mutex);
451 	list_del(&si->stat_list);
452 	mutex_unlock(&f2fs_stat_mutex);
453 
454 	kfree(si);
455 }
456 
457 int __init f2fs_create_root_stats(void)
458 {
459 	struct dentry *file;
460 
461 	f2fs_debugfs_root = debugfs_create_dir("f2fs", NULL);
462 	if (!f2fs_debugfs_root)
463 		return -ENOMEM;
464 
465 	file = debugfs_create_file("status", S_IRUGO, f2fs_debugfs_root,
466 			NULL, &stat_fops);
467 	if (!file) {
468 		debugfs_remove(f2fs_debugfs_root);
469 		f2fs_debugfs_root = NULL;
470 		return -ENOMEM;
471 	}
472 
473 	return 0;
474 }
475 
476 void f2fs_destroy_root_stats(void)
477 {
478 	if (!f2fs_debugfs_root)
479 		return;
480 
481 	debugfs_remove_recursive(f2fs_debugfs_root);
482 	f2fs_debugfs_root = NULL;
483 }
484