fs/ext4/sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/sysfs.c
   4  *
   5  * Copyright (C) 1992, 1993, 1994, 1995
   6  * Remy Card (card@masi.ibp.fr)
   7  * Theodore Ts'o (tytso@mit.edu)
   8  *
   9  */
  10
  11 #include <linux/time.h>
  12 #include <linux/fs.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/slab.h>
  15 #include <linux/proc_fs.h>
  16
  17 #include "ext4.h"
  18 #include "ext4_jbd2.h"
  19
  20 typedef enum {
  21         attr_noop,
  22         attr_delayed_allocation_blocks,
  23         attr_session_write_kbytes,
  24         attr_lifetime_write_kbytes,
  25         attr_reserved_clusters,
  26         attr_inode_readahead,
  27         attr_trigger_test_error,
  28         attr_first_error_time,
  29         attr_last_error_time,
  30         attr_feature,
  31         attr_pointer_ui,
  32         attr_pointer_atomic,
  33         attr_journal_task,
  34 } attr_id_t;
  35
  36 typedef enum {
  37         ptr_explicit,
  38         ptr_ext4_sb_info_offset,
  39         ptr_ext4_super_block_offset,
  40 } attr_ptr_t;
  41
  42 static const char proc_dirname[] = "fs/ext4";
  43 static struct proc_dir_entry *ext4_proc_root;
  44
  45 struct ext4_attr {
  46         struct attribute attr;
  47         short attr_id;
  48         short attr_ptr;
  49         union {
  50                 int offset;
  51                 void *explicit_ptr;
  52         } u;
  53 };
  54
  55 static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  56 {
  57         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  58
  59         if (!sb->s_bdev->bd_part)
  60                 return snprintf(buf, PAGE_SIZE, "0\n");
  61         return snprintf(buf, PAGE_SIZE, "%lu\n",
  62                         (part_stat_read(sb->s_bdev->bd_part,
  63                                         sectors[STAT_WRITE]) -
  64                          sbi->s_sectors_written_start) >> 1);
  65 }
  66
  67 static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  68 {
  69         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  70
  71         if (!sb->s_bdev->bd_part)
  72                 return snprintf(buf, PAGE_SIZE, "0\n");
  73         return snprintf(buf, PAGE_SIZE, "%llu\n",
  74                         (unsigned long long)(sbi->s_kbytes_written +
  75                         ((part_stat_read(sb->s_bdev->bd_part,
  76                                          sectors[STAT_WRITE]) -
  77                           EXT4_SB(sb)->s_sectors_written_start) >> 1)));
  78 }
  79
  80 static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
  81                                           const char *buf, size_t count)
  82 {
  83         unsigned long t;
  84         int ret;
  85
  86         ret = kstrtoul(skip_spaces(buf), 0, &t);
  87         if (ret)
  88                 return ret;
  89
  90         if (t && (!is_power_of_2(t) || t > 0x40000000))
  91                 return -EINVAL;
  92
  93         sbi->s_inode_readahead_blks = t;
  94         return count;
  95 }
  96
  97 static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
  98                                    const char *buf, size_t count)
  99 {
 100         unsigned long long val;
 101         ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
 102                                  sbi->s_cluster_bits);
 103         int ret;
 104
 105         ret = kstrtoull(skip_spaces(buf), 0, &val);
 106         if (ret || val >= clusters)
 107                 return -EINVAL;
 108
 109         atomic64_set(&sbi->s_resv_clusters, val);
 110         return count;
 111 }
 112
 113 static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
 114                                   const char *buf, size_t count)
 115 {
 116         int len = count;
 117
 118         if (!capable(CAP_SYS_ADMIN))
 119                 return -EPERM;
 120
 121         if (len && buf[len-1] == '\n')
 122                 len--;
 123
 124         if (len)
 125                 ext4_error(sbi->s_sb, "%.*s", len, buf);
 126         return count;
 127 }
 128
 129 static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf)
 130 {
 131         if (!sbi->s_journal)
 132                 return snprintf(buf, PAGE_SIZE, "<none>\n");
 133         return snprintf(buf, PAGE_SIZE, "%d\n",
 134                         task_pid_vnr(sbi->s_journal->j_task));
 135 }
 136
 137 #define EXT4_ATTR(_name,_mode,_id)                                      \
 138 static struct ext4_attr ext4_attr_##_name = {                           \
 139         .attr = {.name = __stringify(_name), .mode = _mode },           \
 140         .attr_id = attr_##_id,                                          \
 141 }
 142
 143 #define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
 144
 145 #define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
 146
 147 #define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)       \
 148 static struct ext4_attr ext4_attr_##_name = {                   \
 149         .attr = {.name = __stringify(_name), .mode = _mode },   \
 150         .attr_id = attr_##_id,                                  \
 151         .attr_ptr = ptr_##_struct##_offset,                     \
 152         .u = {                                                  \
 153                 .offset = offsetof(struct _struct, _elname),\
 154         },                                                      \
 155 }
 156
 157 #define EXT4_RO_ATTR_ES_UI(_name,_elname)                               \
 158         EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
 159
 160 #define EXT4_RW_ATTR_SBI_UI(_name,_elname)      \
 161         EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
 162
 163 #define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
 164 static struct ext4_attr ext4_attr_##_name = {                   \
 165         .attr = {.name = __stringify(_name), .mode = _mode },   \
 166         .attr_id = attr_##_id,                                  \
 167         .attr_ptr = ptr_explicit,                               \
 168         .u = {                                                  \
 169                 .explicit_ptr = _ptr,                           \
 170         },                                                      \
 171 }
 172
 173 #define ATTR_LIST(name) &ext4_attr_##name.attr
 174
 175 EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
 176 EXT4_ATTR_FUNC(session_write_kbytes, 0444);
 177 EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
 178 EXT4_ATTR_FUNC(reserved_clusters, 0644);
 179
 180 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
 181                  ext4_sb_info, s_inode_readahead_blks);
 182 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
 183 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
 184 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
 185 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 186 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 187 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 188 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 189 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 190 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
 191 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
 192 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
 193 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
 194 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
 195 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
 196 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 197 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
 198 EXT4_ATTR(first_error_time, 0444, first_error_time);
 199 EXT4_ATTR(last_error_time, 0444, last_error_time);
 200 EXT4_ATTR(journal_task, 0444, journal_task);
 201
 202 static unsigned int old_bump_val = 128;
 203 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
 204
 205 static struct attribute *ext4_attrs[] = {
 206         ATTR_LIST(delayed_allocation_blocks),
 207         ATTR_LIST(session_write_kbytes),
 208         ATTR_LIST(lifetime_write_kbytes),
 209         ATTR_LIST(reserved_clusters),
 210         ATTR_LIST(inode_readahead_blks),
 211         ATTR_LIST(inode_goal),
 212         ATTR_LIST(mb_stats),
 213         ATTR_LIST(mb_max_to_scan),
 214         ATTR_LIST(mb_min_to_scan),
 215         ATTR_LIST(mb_order2_req),
 216         ATTR_LIST(mb_stream_req),
 217         ATTR_LIST(mb_group_prealloc),
 218         ATTR_LIST(max_writeback_mb_bump),
 219         ATTR_LIST(extent_max_zeroout_kb),
 220         ATTR_LIST(trigger_fs_error),
 221         ATTR_LIST(err_ratelimit_interval_ms),
 222         ATTR_LIST(err_ratelimit_burst),
 223         ATTR_LIST(warning_ratelimit_interval_ms),
 224         ATTR_LIST(warning_ratelimit_burst),
 225         ATTR_LIST(msg_ratelimit_interval_ms),
 226         ATTR_LIST(msg_ratelimit_burst),
 227         ATTR_LIST(errors_count),
 228         ATTR_LIST(first_error_time),
 229         ATTR_LIST(last_error_time),
 230         ATTR_LIST(journal_task),
 231         NULL,
 232 };
 233
 234 /* Features this copy of ext4 supports */
 235 EXT4_ATTR_FEATURE(lazy_itable_init);
 236 EXT4_ATTR_FEATURE(batched_discard);
 237 EXT4_ATTR_FEATURE(meta_bg_resize);
 238 #ifdef CONFIG_FS_ENCRYPTION
 239 EXT4_ATTR_FEATURE(encryption);
 240 #endif
 241 #ifdef CONFIG_UNICODE
 242 EXT4_ATTR_FEATURE(casefold);
 243 #endif
 244 EXT4_ATTR_FEATURE(metadata_csum_seed);
 245
 246 static struct attribute *ext4_feat_attrs[] = {
 247         ATTR_LIST(lazy_itable_init),
 248         ATTR_LIST(batched_discard),
 249         ATTR_LIST(meta_bg_resize),
 250 #ifdef CONFIG_FS_ENCRYPTION
 251         ATTR_LIST(encryption),
 252 #endif
 253 #ifdef CONFIG_UNICODE
 254         ATTR_LIST(casefold),
 255 #endif
 256         ATTR_LIST(metadata_csum_seed),
 257         NULL,
 258 };
 259
 260 static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
 261 {
 262         switch (a->attr_ptr) {
 263         case ptr_explicit:
 264                 return a->u.explicit_ptr;
 265         case ptr_ext4_sb_info_offset:
 266                 return (void *) (((char *) sbi) + a->u.offset);
 267         case ptr_ext4_super_block_offset:
 268                 return (void *) (((char *) sbi->s_es) + a->u.offset);
 269         }
 270         return NULL;
 271 }
 272
 273 static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
 274 {
 275         return snprintf(buf, PAGE_SIZE, "%lld",
 276                         ((time64_t)hi << 32) + le32_to_cpu(lo));
 277 }
 278
 279 #define print_tstamp(buf, es, tstamp) \
 280         __print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
 281
 282 static ssize_t ext4_attr_show(struct kobject *kobj,
 283                               struct attribute *attr, char *buf)
 284 {
 285         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 286                                                 s_kobj);
 287         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 288         void *ptr = calc_ptr(a, sbi);
 289
 290         switch (a->attr_id) {
 291         case attr_delayed_allocation_blocks:
 292                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 293                                 (s64) EXT4_C2B(sbi,
 294                        percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
 295         case attr_session_write_kbytes:
 296                 return session_write_kbytes_show(sbi, buf);
 297         case attr_lifetime_write_kbytes:
 298                 return lifetime_write_kbytes_show(sbi, buf);
 299         case attr_reserved_clusters:
 300                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 301                                 (unsigned long long)
 302                                 atomic64_read(&sbi->s_resv_clusters));
 303         case attr_inode_readahead:
 304         case attr_pointer_ui:
 305                 if (!ptr)
 306                         return 0;
 307                 if (a->attr_ptr == ptr_ext4_super_block_offset)
 308                         return snprintf(buf, PAGE_SIZE, "%u\n",
 309                                         le32_to_cpup(ptr));
 310                 else
 311                         return snprintf(buf, PAGE_SIZE, "%u\n",
 312                                         *((unsigned int *) ptr));
 313         case attr_pointer_atomic:
 314                 if (!ptr)
 315                         return 0;
 316                 return snprintf(buf, PAGE_SIZE, "%d\n",
 317                                 atomic_read((atomic_t *) ptr));
 318         case attr_feature:
 319                 return snprintf(buf, PAGE_SIZE, "supported\n");
 320         case attr_first_error_time:
 321                 return print_tstamp(buf, sbi->s_es, s_first_error_time);
 322         case attr_last_error_time:
 323                 return print_tstamp(buf, sbi->s_es, s_last_error_time);
 324         case attr_journal_task:
 325                 return journal_task_show(sbi, buf);
 326         }
 327
 328         return 0;
 329 }
 330
 331 static ssize_t ext4_attr_store(struct kobject *kobj,
 332                                struct attribute *attr,
 333                                const char *buf, size_t len)
 334 {
 335         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 336                                                 s_kobj);
 337         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 338         void *ptr = calc_ptr(a, sbi);
 339         unsigned long t;
 340         int ret;
 341
 342         switch (a->attr_id) {
 343         case attr_reserved_clusters:
 344                 return reserved_clusters_store(sbi, buf, len);
 345         case attr_pointer_ui:
 346                 if (!ptr)
 347                         return 0;
 348                 ret = kstrtoul(skip_spaces(buf), 0, &t);
 349                 if (ret)
 350                         return ret;
 351                 if (a->attr_ptr == ptr_ext4_super_block_offset)
 352                         *((__le32 *) ptr) = cpu_to_le32(t);
 353                 else
 354                         *((unsigned int *) ptr) = t;
 355                 return len;
 356         case attr_inode_readahead:
 357                 return inode_readahead_blks_store(sbi, buf, len);
 358         case attr_trigger_test_error:
 359                 return trigger_test_error(sbi, buf, len);
 360         }
 361         return 0;
 362 }
 363
 364 static void ext4_sb_release(struct kobject *kobj)
 365 {
 366         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 367                                                 s_kobj);
 368         complete(&sbi->s_kobj_unregister);
 369 }
 370
 371 static const struct sysfs_ops ext4_attr_ops = {
 372         .show   = ext4_attr_show,
 373         .store  = ext4_attr_store,
 374 };
 375
 376 static struct kobj_type ext4_sb_ktype = {
 377         .default_attrs  = ext4_attrs,
 378         .sysfs_ops      = &ext4_attr_ops,
 379         .release        = ext4_sb_release,
 380 };
 381
 382 static struct kobj_type ext4_feat_ktype = {
 383         .default_attrs  = ext4_feat_attrs,
 384         .sysfs_ops      = &ext4_attr_ops,
 385         .release        = (void (*)(struct kobject *))kfree,
 386 };
 387
 388 static struct kobject *ext4_root;
 389
 390 static struct kobject *ext4_feat;
 391
 392 int ext4_register_sysfs(struct super_block *sb)
 393 {
 394         struct ext4_sb_info *sbi = EXT4_SB(sb);
 395         int err;
 396
 397         init_completion(&sbi->s_kobj_unregister);
 398         err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
 399                                    "%s", sb->s_id);
 400         if (err) {
 401                 kobject_put(&sbi->s_kobj);
 402                 wait_for_completion(&sbi->s_kobj_unregister);
 403                 return err;
 404         }
 405
 406         if (ext4_proc_root)
 407                 sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
 408         if (sbi->s_proc) {
 409                 proc_create_single_data("options", S_IRUGO, sbi->s_proc,
 410                                 ext4_seq_options_show, sb);
 411                 proc_create_single_data("es_shrinker_info", S_IRUGO,
 412                                 sbi->s_proc, ext4_seq_es_shrinker_info_show,
 413                                 sb);
 414                 proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
 415                                 &ext4_mb_seq_groups_ops, sb);
 416         }
 417         return 0;
 418 }
 419
 420 void ext4_unregister_sysfs(struct super_block *sb)
 421 {
 422         struct ext4_sb_info *sbi = EXT4_SB(sb);
 423
 424         if (sbi->s_proc)
 425                 remove_proc_subtree(sb->s_id, ext4_proc_root);
 426         kobject_del(&sbi->s_kobj);
 427 }
 428
 429 int __init ext4_init_sysfs(void)
 430 {
 431         int ret;
 432
 433         ext4_root = kobject_create_and_add("ext4", fs_kobj);
 434         if (!ext4_root)
 435                 return -ENOMEM;
 436
 437         ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
 438         if (!ext4_feat) {
 439                 ret = -ENOMEM;
 440                 goto root_err;
 441         }
 442
 443         ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
 444                                    ext4_root, "features");
 445         if (ret)
 446                 goto feat_err;
 447
 448         ext4_proc_root = proc_mkdir(proc_dirname, NULL);
 449         return ret;
 450
 451 feat_err:
 452         kobject_put(ext4_feat);
 453         ext4_feat = NULL;
 454 root_err:
 455         kobject_put(ext4_root);
 456         ext4_root = NULL;
 457         return ret;
 458 }
 459
 460 void ext4_exit_sysfs(void)
 461 {
 462         kobject_put(ext4_feat);
 463         ext4_feat = NULL;
 464         kobject_put(ext4_root);
 465         ext4_root = NULL;
 466         remove_proc_entry(proc_dirname, NULL);
 467         ext4_proc_root = NULL;
 468 }
 469