linux/fs/ext4/sysfs.c
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   1/*
   2 *  linux/fs/ext4/sysfs.c
   3 *
   4 * Copyright (C) 1992, 1993, 1994, 1995
   5 * Remy Card (card@masi.ibp.fr)
   6 * Theodore Ts'o (tytso@mit.edu)
   7 *
   8 */
   9
  10#include <linux/time.h>
  11#include <linux/fs.h>
  12#include <linux/seq_file.h>
  13#include <linux/proc_fs.h>
  14
  15#include "ext4.h"
  16#include "ext4_jbd2.h"
  17
  18typedef enum {
  19        attr_noop,
  20        attr_delayed_allocation_blocks,
  21        attr_session_write_kbytes,
  22        attr_lifetime_write_kbytes,
  23        attr_reserved_clusters,
  24        attr_inode_readahead,
  25        attr_trigger_test_error,
  26        attr_feature,
  27        attr_pointer_ui,
  28        attr_pointer_atomic,
  29} attr_id_t;
  30
  31typedef enum {
  32        ptr_explicit,
  33        ptr_ext4_sb_info_offset,
  34        ptr_ext4_super_block_offset,
  35} attr_ptr_t;
  36
  37static const char *proc_dirname = "fs/ext4";
  38static struct proc_dir_entry *ext4_proc_root;
  39
  40struct ext4_attr {
  41        struct attribute attr;
  42        short attr_id;
  43        short attr_ptr;
  44        union {
  45                int offset;
  46                void *explicit_ptr;
  47        } u;
  48};
  49
  50static ssize_t session_write_kbytes_show(struct ext4_attr *a,
  51                                         struct ext4_sb_info *sbi, char *buf)
  52{
  53        struct super_block *sb = sbi->s_buddy_cache->i_sb;
  54
  55        if (!sb->s_bdev->bd_part)
  56                return snprintf(buf, PAGE_SIZE, "0\n");
  57        return snprintf(buf, PAGE_SIZE, "%lu\n",
  58                        (part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  59                         sbi->s_sectors_written_start) >> 1);
  60}
  61
  62static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
  63                                          struct ext4_sb_info *sbi, char *buf)
  64{
  65        struct super_block *sb = sbi->s_buddy_cache->i_sb;
  66
  67        if (!sb->s_bdev->bd_part)
  68                return snprintf(buf, PAGE_SIZE, "0\n");
  69        return snprintf(buf, PAGE_SIZE, "%llu\n",
  70                        (unsigned long long)(sbi->s_kbytes_written +
  71                        ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  72                          EXT4_SB(sb)->s_sectors_written_start) >> 1)));
  73}
  74
  75static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
  76                                          struct ext4_sb_info *sbi,
  77                                          const char *buf, size_t count)
  78{
  79        unsigned long t;
  80        int ret;
  81
  82        ret = kstrtoul(skip_spaces(buf), 0, &t);
  83        if (ret)
  84                return ret;
  85
  86        if (t && (!is_power_of_2(t) || t > 0x40000000))
  87                return -EINVAL;
  88
  89        sbi->s_inode_readahead_blks = t;
  90        return count;
  91}
  92
  93static ssize_t reserved_clusters_store(struct ext4_attr *a,
  94                                   struct ext4_sb_info *sbi,
  95                                   const char *buf, size_t count)
  96{
  97        unsigned long long val;
  98        ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
  99                                 sbi->s_cluster_bits);
 100        int ret;
 101
 102        ret = kstrtoull(skip_spaces(buf), 0, &val);
 103        if (!ret || val >= clusters)
 104                return -EINVAL;
 105
 106        atomic64_set(&sbi->s_resv_clusters, val);
 107        return count;
 108}
 109
 110static ssize_t trigger_test_error(struct ext4_attr *a,
 111                                  struct ext4_sb_info *sbi,
 112                                  const char *buf, size_t count)
 113{
 114        int len = count;
 115
 116        if (!capable(CAP_SYS_ADMIN))
 117                return -EPERM;
 118
 119        if (len && buf[len-1] == '\n')
 120                len--;
 121
 122        if (len)
 123                ext4_error(sbi->s_sb, "%.*s", len, buf);
 124        return count;
 125}
 126
 127#define EXT4_ATTR(_name,_mode,_id)                                      \
 128static struct ext4_attr ext4_attr_##_name = {                           \
 129        .attr = {.name = __stringify(_name), .mode = _mode },           \
 130        .attr_id = attr_##_id,                                          \
 131}
 132
 133#define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
 134
 135#define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
 136
 137#define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)       \
 138static struct ext4_attr ext4_attr_##_name = {                   \
 139        .attr = {.name = __stringify(_name), .mode = _mode },   \
 140        .attr_id = attr_##_id,                                  \
 141        .attr_ptr = ptr_##_struct##_offset,                     \
 142        .u = {                                                  \
 143                .offset = offsetof(struct _struct, _elname),\
 144        },                                                      \
 145}
 146
 147#define EXT4_RO_ATTR_ES_UI(_name,_elname)                               \
 148        EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
 149
 150#define EXT4_RW_ATTR_SBI_UI(_name,_elname)      \
 151        EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
 152
 153#define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
 154static struct ext4_attr ext4_attr_##_name = {                   \
 155        .attr = {.name = __stringify(_name), .mode = _mode },   \
 156        .attr_id = attr_##_id,                                  \
 157        .attr_ptr = ptr_explicit,                               \
 158        .u = {                                                  \
 159                .explicit_ptr = _ptr,                           \
 160        },                                                      \
 161}
 162
 163#define ATTR_LIST(name) &ext4_attr_##name.attr
 164
 165EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
 166EXT4_ATTR_FUNC(session_write_kbytes, 0444);
 167EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
 168EXT4_ATTR_FUNC(reserved_clusters, 0644);
 169
 170EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
 171                 ext4_sb_info, s_inode_readahead_blks);
 172EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
 173EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
 174EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
 175EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 176EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 177EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 178EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 179EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 180EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
 181EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
 182EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
 183EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
 184EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
 185EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
 186EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 187EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
 188EXT4_RO_ATTR_ES_UI(first_error_time, s_first_error_time);
 189EXT4_RO_ATTR_ES_UI(last_error_time, s_last_error_time);
 190
 191static unsigned int old_bump_val = 128;
 192EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
 193
 194static struct attribute *ext4_attrs[] = {
 195        ATTR_LIST(delayed_allocation_blocks),
 196        ATTR_LIST(session_write_kbytes),
 197        ATTR_LIST(lifetime_write_kbytes),
 198        ATTR_LIST(reserved_clusters),
 199        ATTR_LIST(inode_readahead_blks),
 200        ATTR_LIST(inode_goal),
 201        ATTR_LIST(mb_stats),
 202        ATTR_LIST(mb_max_to_scan),
 203        ATTR_LIST(mb_min_to_scan),
 204        ATTR_LIST(mb_order2_req),
 205        ATTR_LIST(mb_stream_req),
 206        ATTR_LIST(mb_group_prealloc),
 207        ATTR_LIST(max_writeback_mb_bump),
 208        ATTR_LIST(extent_max_zeroout_kb),
 209        ATTR_LIST(trigger_fs_error),
 210        ATTR_LIST(err_ratelimit_interval_ms),
 211        ATTR_LIST(err_ratelimit_burst),
 212        ATTR_LIST(warning_ratelimit_interval_ms),
 213        ATTR_LIST(warning_ratelimit_burst),
 214        ATTR_LIST(msg_ratelimit_interval_ms),
 215        ATTR_LIST(msg_ratelimit_burst),
 216        ATTR_LIST(errors_count),
 217        ATTR_LIST(first_error_time),
 218        ATTR_LIST(last_error_time),
 219        NULL,
 220};
 221
 222/* Features this copy of ext4 supports */
 223EXT4_ATTR_FEATURE(lazy_itable_init);
 224EXT4_ATTR_FEATURE(batched_discard);
 225EXT4_ATTR_FEATURE(meta_bg_resize);
 226EXT4_ATTR_FEATURE(encryption);
 227EXT4_ATTR_FEATURE(metadata_csum_seed);
 228
 229static struct attribute *ext4_feat_attrs[] = {
 230        ATTR_LIST(lazy_itable_init),
 231        ATTR_LIST(batched_discard),
 232        ATTR_LIST(meta_bg_resize),
 233        ATTR_LIST(encryption),
 234        ATTR_LIST(metadata_csum_seed),
 235        NULL,
 236};
 237
 238static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
 239{
 240        switch (a->attr_ptr) {
 241        case ptr_explicit:
 242                return a->u.explicit_ptr;
 243        case ptr_ext4_sb_info_offset:
 244                return (void *) (((char *) sbi) + a->u.offset);
 245        case ptr_ext4_super_block_offset:
 246                return (void *) (((char *) sbi->s_es) + a->u.offset);
 247        }
 248        return NULL;
 249}
 250
 251static ssize_t ext4_attr_show(struct kobject *kobj,
 252                              struct attribute *attr, char *buf)
 253{
 254        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 255                                                s_kobj);
 256        struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 257        void *ptr = calc_ptr(a, sbi);
 258
 259        switch (a->attr_id) {
 260        case attr_delayed_allocation_blocks:
 261                return snprintf(buf, PAGE_SIZE, "%llu\n",
 262                                (s64) EXT4_C2B(sbi,
 263                       percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
 264        case attr_session_write_kbytes:
 265                return session_write_kbytes_show(a, sbi, buf);
 266        case attr_lifetime_write_kbytes:
 267                return lifetime_write_kbytes_show(a, sbi, buf);
 268        case attr_reserved_clusters:
 269                return snprintf(buf, PAGE_SIZE, "%llu\n",
 270                                (unsigned long long)
 271                                atomic64_read(&sbi->s_resv_clusters));
 272        case attr_inode_readahead:
 273        case attr_pointer_ui:
 274                if (!ptr)
 275                        return 0;
 276                return snprintf(buf, PAGE_SIZE, "%u\n",
 277                                *((unsigned int *) ptr));
 278        case attr_pointer_atomic:
 279                if (!ptr)
 280                        return 0;
 281                return snprintf(buf, PAGE_SIZE, "%d\n",
 282                                atomic_read((atomic_t *) ptr));
 283        case attr_feature:
 284                return snprintf(buf, PAGE_SIZE, "supported\n");
 285        }
 286
 287        return 0;
 288}
 289
 290static ssize_t ext4_attr_store(struct kobject *kobj,
 291                               struct attribute *attr,
 292                               const char *buf, size_t len)
 293{
 294        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 295                                                s_kobj);
 296        struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 297        void *ptr = calc_ptr(a, sbi);
 298        unsigned long t;
 299        int ret;
 300
 301        switch (a->attr_id) {
 302        case attr_reserved_clusters:
 303                return reserved_clusters_store(a, sbi, buf, len);
 304        case attr_pointer_ui:
 305                if (!ptr)
 306                        return 0;
 307                ret = kstrtoul(skip_spaces(buf), 0, &t);
 308                if (ret)
 309                        return ret;
 310                *((unsigned int *) ptr) = t;
 311                return len;
 312        case attr_inode_readahead:
 313                return inode_readahead_blks_store(a, sbi, buf, len);
 314        case attr_trigger_test_error:
 315                return trigger_test_error(a, sbi, buf, len);
 316        }
 317        return 0;
 318}
 319
 320static void ext4_sb_release(struct kobject *kobj)
 321{
 322        struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 323                                                s_kobj);
 324        complete(&sbi->s_kobj_unregister);
 325}
 326
 327static const struct sysfs_ops ext4_attr_ops = {
 328        .show   = ext4_attr_show,
 329        .store  = ext4_attr_store,
 330};
 331
 332static struct kobj_type ext4_sb_ktype = {
 333        .default_attrs  = ext4_attrs,
 334        .sysfs_ops      = &ext4_attr_ops,
 335        .release        = ext4_sb_release,
 336};
 337
 338static struct kobj_type ext4_ktype = {
 339        .sysfs_ops      = &ext4_attr_ops,
 340};
 341
 342static struct kset ext4_kset = {
 343        .kobj   = {.ktype = &ext4_ktype},
 344};
 345
 346static struct kobj_type ext4_feat_ktype = {
 347        .default_attrs  = ext4_feat_attrs,
 348        .sysfs_ops      = &ext4_attr_ops,
 349};
 350
 351static struct kobject ext4_feat = {
 352        .kset   = &ext4_kset,
 353};
 354
 355#define PROC_FILE_SHOW_DEFN(name) \
 356static int name##_open(struct inode *inode, struct file *file) \
 357{ \
 358        return single_open(file, ext4_seq_##name##_show, PDE_DATA(inode)); \
 359} \
 360\
 361static const struct file_operations ext4_seq_##name##_fops = { \
 362        .owner          = THIS_MODULE, \
 363        .open           = name##_open, \
 364        .read           = seq_read, \
 365        .llseek         = seq_lseek, \
 366        .release        = single_release, \
 367}
 368
 369#define PROC_FILE_LIST(name) \
 370        { __stringify(name), &ext4_seq_##name##_fops }
 371
 372PROC_FILE_SHOW_DEFN(es_shrinker_info);
 373PROC_FILE_SHOW_DEFN(options);
 374
 375static struct ext4_proc_files {
 376        const char *name;
 377        const struct file_operations *fops;
 378} proc_files[] = {
 379        PROC_FILE_LIST(options),
 380        PROC_FILE_LIST(es_shrinker_info),
 381        PROC_FILE_LIST(mb_groups),
 382        { NULL, NULL },
 383};
 384
 385int ext4_register_sysfs(struct super_block *sb)
 386{
 387        struct ext4_sb_info *sbi = EXT4_SB(sb);
 388        struct ext4_proc_files *p;
 389        int err;
 390
 391        sbi->s_kobj.kset = &ext4_kset;
 392        init_completion(&sbi->s_kobj_unregister);
 393        err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, NULL,
 394                                   "%s", sb->s_id);
 395        if (err)
 396                return err;
 397
 398        if (ext4_proc_root)
 399                sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
 400
 401        if (sbi->s_proc) {
 402                for (p = proc_files; p->name; p++)
 403                        proc_create_data(p->name, S_IRUGO, sbi->s_proc,
 404                                         p->fops, sb);
 405        }
 406        return 0;
 407}
 408
 409void ext4_unregister_sysfs(struct super_block *sb)
 410{
 411        struct ext4_sb_info *sbi = EXT4_SB(sb);
 412        struct ext4_proc_files *p;
 413
 414        if (sbi->s_proc) {
 415                for (p = proc_files; p->name; p++)
 416                        remove_proc_entry(p->name, sbi->s_proc);
 417                remove_proc_entry(sb->s_id, ext4_proc_root);
 418        }
 419        kobject_del(&sbi->s_kobj);
 420}
 421
 422int __init ext4_init_sysfs(void)
 423{
 424        int ret;
 425
 426        kobject_set_name(&ext4_kset.kobj, "ext4");
 427        ext4_kset.kobj.parent = fs_kobj;
 428        ret = kset_register(&ext4_kset);
 429        if (ret)
 430                return ret;
 431
 432        ret = kobject_init_and_add(&ext4_feat, &ext4_feat_ktype,
 433                                   NULL, "features");
 434        if (ret)
 435                kset_unregister(&ext4_kset);
 436        else
 437                ext4_proc_root = proc_mkdir(proc_dirname, NULL);
 438        return ret;
 439}
 440
 441void ext4_exit_sysfs(void)
 442{
 443        kobject_put(&ext4_feat);
 444        kset_unregister(&ext4_kset);
 445        remove_proc_entry(proc_dirname, NULL);
 446        ext4_proc_root = NULL;
 447}
 448
 449