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_id_t;
  34
  35 typedef enum {
  36         ptr_explicit,
  37         ptr_ext4_sb_info_offset,
  38         ptr_ext4_super_block_offset,
  39 } attr_ptr_t;
  40
  41 static const char proc_dirname[] = "fs/ext4";
  42 static struct proc_dir_entry *ext4_proc_root;
  43
  44 struct ext4_attr {
  45         struct attribute attr;
  46         short attr_id;
  47         short attr_ptr;
  48         union {
  49                 int offset;
  50                 void *explicit_ptr;
  51         } u;
  52 };
  53
  54 static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  55 {
  56         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  57
  58         if (!sb->s_bdev->bd_part)
  59                 return snprintf(buf, PAGE_SIZE, "0\n");
  60         return snprintf(buf, PAGE_SIZE, "%lu\n",
  61                         (part_stat_read(sb->s_bdev->bd_part,
  62                                         sectors[STAT_WRITE]) -
  63                          sbi->s_sectors_written_start) >> 1);
  64 }
  65
  66 static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  67 {
  68         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  69
  70         if (!sb->s_bdev->bd_part)
  71                 return snprintf(buf, PAGE_SIZE, "0\n");
  72         return snprintf(buf, PAGE_SIZE, "%llu\n",
  73                         (unsigned long long)(sbi->s_kbytes_written +
  74                         ((part_stat_read(sb->s_bdev->bd_part,
  75                                          sectors[STAT_WRITE]) -
  76                           EXT4_SB(sb)->s_sectors_written_start) >> 1)));
  77 }
  78
  79 static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
  80                                           const char *buf, size_t count)
  81 {
  82         unsigned long t;
  83         int ret;
  84
  85         ret = kstrtoul(skip_spaces(buf), 0, &t);
  86         if (ret)
  87                 return ret;
  88
  89         if (t && (!is_power_of_2(t) || t > 0x40000000))
  90                 return -EINVAL;
  91
  92         sbi->s_inode_readahead_blks = t;
  93         return count;
  94 }
  95
  96 static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
  97                                    const char *buf, size_t count)
  98 {
  99         unsigned long long val;
 100         ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
 101                                  sbi->s_cluster_bits);
 102         int ret;
 103
 104         ret = kstrtoull(skip_spaces(buf), 0, &val);
 105         if (ret || val >= clusters)
 106                 return -EINVAL;
 107
 108         atomic64_set(&sbi->s_resv_clusters, val);
 109         return count;
 110 }
 111
 112 static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
 113                                   const char *buf, size_t count)
 114 {
 115         int len = count;
 116
 117         if (!capable(CAP_SYS_ADMIN))
 118                 return -EPERM;
 119
 120         if (len && buf[len-1] == '\n')
 121                 len--;
 122
 123         if (len)
 124                 ext4_error(sbi->s_sb, "%.*s", len, buf);
 125         return count;
 126 }
 127
 128 #define EXT4_ATTR(_name,_mode,_id)                                      \
 129 static struct ext4_attr ext4_attr_##_name = {                           \
 130         .attr = {.name = __stringify(_name), .mode = _mode },           \
 131         .attr_id = attr_##_id,                                          \
 132 }
 133
 134 #define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
 135
 136 #define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
 137
 138 #define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)       \
 139 static struct ext4_attr ext4_attr_##_name = {                   \
 140         .attr = {.name = __stringify(_name), .mode = _mode },   \
 141         .attr_id = attr_##_id,                                  \
 142         .attr_ptr = ptr_##_struct##_offset,                     \
 143         .u = {                                                  \
 144                 .offset = offsetof(struct _struct, _elname),\
 145         },                                                      \
 146 }
 147
 148 #define EXT4_RO_ATTR_ES_UI(_name,_elname)                               \
 149         EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
 150
 151 #define EXT4_RW_ATTR_SBI_UI(_name,_elname)      \
 152         EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
 153
 154 #define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
 155 static struct ext4_attr ext4_attr_##_name = {                   \
 156         .attr = {.name = __stringify(_name), .mode = _mode },   \
 157         .attr_id = attr_##_id,                                  \
 158         .attr_ptr = ptr_explicit,                               \
 159         .u = {                                                  \
 160                 .explicit_ptr = _ptr,                           \
 161         },                                                      \
 162 }
 163
 164 #define ATTR_LIST(name) &ext4_attr_##name.attr
 165
 166 EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
 167 EXT4_ATTR_FUNC(session_write_kbytes, 0444);
 168 EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
 169 EXT4_ATTR_FUNC(reserved_clusters, 0644);
 170
 171 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
 172                  ext4_sb_info, s_inode_readahead_blks);
 173 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
 174 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
 175 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
 176 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 177 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 178 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 179 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 180 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 181 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
 182 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
 183 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
 184 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
 185 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
 186 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
 187 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 188 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
 189 EXT4_ATTR(first_error_time, 0444, first_error_time);
 190 EXT4_ATTR(last_error_time, 0444, last_error_time);
 191
 192 static unsigned int old_bump_val = 128;
 193 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
 194
 195 static struct attribute *ext4_attrs[] = {
 196         ATTR_LIST(delayed_allocation_blocks),
 197         ATTR_LIST(session_write_kbytes),
 198         ATTR_LIST(lifetime_write_kbytes),
 199         ATTR_LIST(reserved_clusters),
 200         ATTR_LIST(inode_readahead_blks),
 201         ATTR_LIST(inode_goal),
 202         ATTR_LIST(mb_stats),
 203         ATTR_LIST(mb_max_to_scan),
 204         ATTR_LIST(mb_min_to_scan),
 205         ATTR_LIST(mb_order2_req),
 206         ATTR_LIST(mb_stream_req),
 207         ATTR_LIST(mb_group_prealloc),
 208         ATTR_LIST(max_writeback_mb_bump),
 209         ATTR_LIST(extent_max_zeroout_kb),
 210         ATTR_LIST(trigger_fs_error),
 211         ATTR_LIST(err_ratelimit_interval_ms),
 212         ATTR_LIST(err_ratelimit_burst),
 213         ATTR_LIST(warning_ratelimit_interval_ms),
 214         ATTR_LIST(warning_ratelimit_burst),
 215         ATTR_LIST(msg_ratelimit_interval_ms),
 216         ATTR_LIST(msg_ratelimit_burst),
 217         ATTR_LIST(errors_count),
 218         ATTR_LIST(first_error_time),
 219         ATTR_LIST(last_error_time),
 220         NULL,
 221 };
 222
 223 /* Features this copy of ext4 supports */
 224 EXT4_ATTR_FEATURE(lazy_itable_init);
 225 EXT4_ATTR_FEATURE(batched_discard);
 226 EXT4_ATTR_FEATURE(meta_bg_resize);
 227 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 228 EXT4_ATTR_FEATURE(encryption);
 229 #endif
 230 EXT4_ATTR_FEATURE(metadata_csum_seed);
 231
 232 static struct attribute *ext4_feat_attrs[] = {
 233         ATTR_LIST(lazy_itable_init),
 234         ATTR_LIST(batched_discard),
 235         ATTR_LIST(meta_bg_resize),
 236 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 237         ATTR_LIST(encryption),
 238 #endif
 239         ATTR_LIST(metadata_csum_seed),
 240         NULL,
 241 };
 242
 243 static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
 244 {
 245         switch (a->attr_ptr) {
 246         case ptr_explicit:
 247                 return a->u.explicit_ptr;
 248         case ptr_ext4_sb_info_offset:
 249                 return (void *) (((char *) sbi) + a->u.offset);
 250         case ptr_ext4_super_block_offset:
 251                 return (void *) (((char *) sbi->s_es) + a->u.offset);
 252         }
 253         return NULL;
 254 }
 255
 256 static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
 257 {
 258         return snprintf(buf, PAGE_SIZE, "%lld",
 259                         ((time64_t)hi << 32) + le32_to_cpu(lo));
 260 }
 261
 262 #define print_tstamp(buf, es, tstamp) \
 263         __print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
 264
 265 static ssize_t ext4_attr_show(struct kobject *kobj,
 266                               struct attribute *attr, char *buf)
 267 {
 268         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 269                                                 s_kobj);
 270         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 271         void *ptr = calc_ptr(a, sbi);
 272
 273         switch (a->attr_id) {
 274         case attr_delayed_allocation_blocks:
 275                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 276                                 (s64) EXT4_C2B(sbi,
 277                        percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
 278         case attr_session_write_kbytes:
 279                 return session_write_kbytes_show(sbi, buf);
 280         case attr_lifetime_write_kbytes:
 281                 return lifetime_write_kbytes_show(sbi, buf);
 282         case attr_reserved_clusters:
 283                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 284                                 (unsigned long long)
 285                                 atomic64_read(&sbi->s_resv_clusters));
 286         case attr_inode_readahead:
 287         case attr_pointer_ui:
 288                 if (!ptr)
 289                         return 0;
 290                 if (a->attr_ptr == ptr_ext4_super_block_offset)
 291                         return snprintf(buf, PAGE_SIZE, "%u\n",
 292                                         le32_to_cpup(ptr));
 293                 else
 294                         return snprintf(buf, PAGE_SIZE, "%u\n",
 295                                         *((unsigned int *) ptr));
 296         case attr_pointer_atomic:
 297                 if (!ptr)
 298                         return 0;
 299                 return snprintf(buf, PAGE_SIZE, "%d\n",
 300                                 atomic_read((atomic_t *) ptr));
 301         case attr_feature:
 302                 return snprintf(buf, PAGE_SIZE, "supported\n");
 303         case attr_first_error_time:
 304                 return print_tstamp(buf, sbi->s_es, s_first_error_time);
 305         case attr_last_error_time:
 306                 return print_tstamp(buf, sbi->s_es, s_last_error_time);
 307         }
 308
 309         return 0;
 310 }
 311
 312 static ssize_t ext4_attr_store(struct kobject *kobj,
 313                                struct attribute *attr,
 314                                const char *buf, size_t len)
 315 {
 316         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 317                                                 s_kobj);
 318         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 319         void *ptr = calc_ptr(a, sbi);
 320         unsigned long t;
 321         int ret;
 322
 323         switch (a->attr_id) {
 324         case attr_reserved_clusters:
 325                 return reserved_clusters_store(sbi, buf, len);
 326         case attr_pointer_ui:
 327                 if (!ptr)
 328                         return 0;
 329                 ret = kstrtoul(skip_spaces(buf), 0, &t);
 330                 if (ret)
 331                         return ret;
 332                 if (a->attr_ptr == ptr_ext4_super_block_offset)
 333                         *((__le32 *) ptr) = cpu_to_le32(t);
 334                 else
 335                         *((unsigned int *) ptr) = t;
 336                 return len;
 337         case attr_inode_readahead:
 338                 return inode_readahead_blks_store(sbi, buf, len);
 339         case attr_trigger_test_error:
 340                 return trigger_test_error(sbi, buf, len);
 341         }
 342         return 0;
 343 }
 344
 345 static void ext4_sb_release(struct kobject *kobj)
 346 {
 347         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 348                                                 s_kobj);
 349         complete(&sbi->s_kobj_unregister);
 350 }
 351
 352 static const struct sysfs_ops ext4_attr_ops = {
 353         .show   = ext4_attr_show,
 354         .store  = ext4_attr_store,
 355 };
 356
 357 static struct kobj_type ext4_sb_ktype = {
 358         .default_attrs  = ext4_attrs,
 359         .sysfs_ops      = &ext4_attr_ops,
 360         .release        = ext4_sb_release,
 361 };
 362
 363 static struct kobj_type ext4_feat_ktype = {
 364         .default_attrs  = ext4_feat_attrs,
 365         .sysfs_ops      = &ext4_attr_ops,
 366         .release        = (void (*)(struct kobject *))kfree,
 367 };
 368
 369 static struct kobject *ext4_root;
 370
 371 static struct kobject *ext4_feat;
 372
 373 int ext4_register_sysfs(struct super_block *sb)
 374 {
 375         struct ext4_sb_info *sbi = EXT4_SB(sb);
 376         int err;
 377
 378         init_completion(&sbi->s_kobj_unregister);
 379         err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
 380                                    "%s", sb->s_id);
 381         if (err) {
 382                 kobject_put(&sbi->s_kobj);
 383                 wait_for_completion(&sbi->s_kobj_unregister);
 384                 return err;
 385         }
 386
 387         if (ext4_proc_root)
 388                 sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
 389         if (sbi->s_proc) {
 390                 proc_create_single_data("options", S_IRUGO, sbi->s_proc,
 391                                 ext4_seq_options_show, sb);
 392                 proc_create_single_data("es_shrinker_info", S_IRUGO,
 393                                 sbi->s_proc, ext4_seq_es_shrinker_info_show,
 394                                 sb);
 395                 proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
 396                                 &ext4_mb_seq_groups_ops, sb);
 397         }
 398         return 0;
 399 }
 400
 401 void ext4_unregister_sysfs(struct super_block *sb)
 402 {
 403         struct ext4_sb_info *sbi = EXT4_SB(sb);
 404
 405         if (sbi->s_proc)
 406                 remove_proc_subtree(sb->s_id, ext4_proc_root);
 407         kobject_del(&sbi->s_kobj);
 408 }
 409
 410 int __init ext4_init_sysfs(void)
 411 {
 412         int ret;
 413
 414         ext4_root = kobject_create_and_add("ext4", fs_kobj);
 415         if (!ext4_root)
 416                 return -ENOMEM;
 417
 418         ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
 419         if (!ext4_feat) {
 420                 ret = -ENOMEM;
 421                 goto root_err;
 422         }
 423
 424         ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
 425                                    ext4_root, "features");
 426         if (ret)
 427                 goto feat_err;
 428
 429         ext4_proc_root = proc_mkdir(proc_dirname, NULL);
 430         return ret;
 431
 432 feat_err:
 433         kobject_put(ext4_feat);
 434         ext4_feat = NULL;
 435 root_err:
 436         kobject_put(ext4_root);
 437         ext4_root = NULL;
 438         return ret;
 439 }
 440
 441 void ext4_exit_sysfs(void)
 442 {
 443         kobject_put(ext4_feat);
 444         ext4_feat = NULL;
 445         kobject_put(ext4_root);
 446         ext4_root = NULL;
 447         remove_proc_entry(proc_dirname, NULL);
 448         ext4_proc_root = NULL;
 449 }
 450