![Eric Biggers](/assets/img/avatar_default.png)
Constify static data in ext4 that is never (intentionally) modified so that it is placed in .rodata and benefits from memory protection. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
452 lines
12 KiB
C
452 lines
12 KiB
C
/*
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* linux/fs/ext4/sysfs.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Theodore Ts'o (tytso@mit.edu)
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*
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include "ext4.h"
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#include "ext4_jbd2.h"
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typedef enum {
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attr_noop,
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attr_delayed_allocation_blocks,
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attr_session_write_kbytes,
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attr_lifetime_write_kbytes,
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attr_reserved_clusters,
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attr_inode_readahead,
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attr_trigger_test_error,
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attr_feature,
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attr_pointer_ui,
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attr_pointer_atomic,
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} attr_id_t;
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typedef enum {
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ptr_explicit,
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ptr_ext4_sb_info_offset,
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ptr_ext4_super_block_offset,
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} attr_ptr_t;
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static const char proc_dirname[] = "fs/ext4";
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static struct proc_dir_entry *ext4_proc_root;
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struct ext4_attr {
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struct attribute attr;
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short attr_id;
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short attr_ptr;
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union {
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int offset;
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void *explicit_ptr;
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} u;
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};
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static ssize_t session_write_kbytes_show(struct ext4_attr *a,
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struct ext4_sb_info *sbi, char *buf)
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{
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struct super_block *sb = sbi->s_buddy_cache->i_sb;
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if (!sb->s_bdev->bd_part)
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return snprintf(buf, PAGE_SIZE, "0\n");
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return snprintf(buf, PAGE_SIZE, "%lu\n",
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(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
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sbi->s_sectors_written_start) >> 1);
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}
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static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
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struct ext4_sb_info *sbi, char *buf)
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{
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struct super_block *sb = sbi->s_buddy_cache->i_sb;
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if (!sb->s_bdev->bd_part)
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return snprintf(buf, PAGE_SIZE, "0\n");
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return snprintf(buf, PAGE_SIZE, "%llu\n",
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(unsigned long long)(sbi->s_kbytes_written +
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((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
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EXT4_SB(sb)->s_sectors_written_start) >> 1)));
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}
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static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
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struct ext4_sb_info *sbi,
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const char *buf, size_t count)
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{
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unsigned long t;
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int ret;
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ret = kstrtoul(skip_spaces(buf), 0, &t);
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if (ret)
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return ret;
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if (t && (!is_power_of_2(t) || t > 0x40000000))
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return -EINVAL;
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sbi->s_inode_readahead_blks = t;
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return count;
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}
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static ssize_t reserved_clusters_store(struct ext4_attr *a,
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struct ext4_sb_info *sbi,
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const char *buf, size_t count)
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{
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unsigned long long val;
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ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
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sbi->s_cluster_bits);
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int ret;
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ret = kstrtoull(skip_spaces(buf), 0, &val);
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if (!ret || val >= clusters)
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return -EINVAL;
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atomic64_set(&sbi->s_resv_clusters, val);
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return count;
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}
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static ssize_t trigger_test_error(struct ext4_attr *a,
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struct ext4_sb_info *sbi,
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const char *buf, size_t count)
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{
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int len = count;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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if (len && buf[len-1] == '\n')
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len--;
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if (len)
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ext4_error(sbi->s_sb, "%.*s", len, buf);
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return count;
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}
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#define EXT4_ATTR(_name,_mode,_id) \
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static struct ext4_attr ext4_attr_##_name = { \
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.attr = {.name = __stringify(_name), .mode = _mode }, \
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.attr_id = attr_##_id, \
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}
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#define EXT4_ATTR_FUNC(_name,_mode) EXT4_ATTR(_name,_mode,_name)
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#define EXT4_ATTR_FEATURE(_name) EXT4_ATTR(_name, 0444, feature)
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#define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname) \
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static struct ext4_attr ext4_attr_##_name = { \
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.attr = {.name = __stringify(_name), .mode = _mode }, \
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.attr_id = attr_##_id, \
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.attr_ptr = ptr_##_struct##_offset, \
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.u = { \
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.offset = offsetof(struct _struct, _elname),\
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}, \
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}
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#define EXT4_RO_ATTR_ES_UI(_name,_elname) \
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EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
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#define EXT4_RW_ATTR_SBI_UI(_name,_elname) \
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EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
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#define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
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static struct ext4_attr ext4_attr_##_name = { \
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.attr = {.name = __stringify(_name), .mode = _mode }, \
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.attr_id = attr_##_id, \
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.attr_ptr = ptr_explicit, \
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.u = { \
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.explicit_ptr = _ptr, \
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}, \
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}
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#define ATTR_LIST(name) &ext4_attr_##name.attr
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EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
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EXT4_ATTR_FUNC(session_write_kbytes, 0444);
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EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
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EXT4_ATTR_FUNC(reserved_clusters, 0644);
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EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
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ext4_sb_info, s_inode_readahead_blks);
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EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
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EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
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EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
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EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
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EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
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EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
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EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
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EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
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EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
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EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
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EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
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EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
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EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
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EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
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EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
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EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
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EXT4_RO_ATTR_ES_UI(first_error_time, s_first_error_time);
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EXT4_RO_ATTR_ES_UI(last_error_time, s_last_error_time);
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static unsigned int old_bump_val = 128;
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EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
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static struct attribute *ext4_attrs[] = {
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ATTR_LIST(delayed_allocation_blocks),
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ATTR_LIST(session_write_kbytes),
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ATTR_LIST(lifetime_write_kbytes),
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ATTR_LIST(reserved_clusters),
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ATTR_LIST(inode_readahead_blks),
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ATTR_LIST(inode_goal),
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ATTR_LIST(mb_stats),
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ATTR_LIST(mb_max_to_scan),
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ATTR_LIST(mb_min_to_scan),
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ATTR_LIST(mb_order2_req),
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ATTR_LIST(mb_stream_req),
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ATTR_LIST(mb_group_prealloc),
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ATTR_LIST(max_writeback_mb_bump),
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ATTR_LIST(extent_max_zeroout_kb),
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ATTR_LIST(trigger_fs_error),
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ATTR_LIST(err_ratelimit_interval_ms),
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ATTR_LIST(err_ratelimit_burst),
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ATTR_LIST(warning_ratelimit_interval_ms),
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ATTR_LIST(warning_ratelimit_burst),
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ATTR_LIST(msg_ratelimit_interval_ms),
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ATTR_LIST(msg_ratelimit_burst),
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ATTR_LIST(errors_count),
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ATTR_LIST(first_error_time),
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ATTR_LIST(last_error_time),
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NULL,
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};
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/* Features this copy of ext4 supports */
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EXT4_ATTR_FEATURE(lazy_itable_init);
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EXT4_ATTR_FEATURE(batched_discard);
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EXT4_ATTR_FEATURE(meta_bg_resize);
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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EXT4_ATTR_FEATURE(encryption);
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#endif
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EXT4_ATTR_FEATURE(metadata_csum_seed);
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static struct attribute *ext4_feat_attrs[] = {
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ATTR_LIST(lazy_itable_init),
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ATTR_LIST(batched_discard),
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ATTR_LIST(meta_bg_resize),
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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ATTR_LIST(encryption),
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#endif
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ATTR_LIST(metadata_csum_seed),
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NULL,
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};
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static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
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{
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switch (a->attr_ptr) {
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case ptr_explicit:
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return a->u.explicit_ptr;
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case ptr_ext4_sb_info_offset:
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return (void *) (((char *) sbi) + a->u.offset);
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case ptr_ext4_super_block_offset:
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return (void *) (((char *) sbi->s_es) + a->u.offset);
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}
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return NULL;
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}
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static ssize_t ext4_attr_show(struct kobject *kobj,
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struct attribute *attr, char *buf)
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{
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struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
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s_kobj);
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struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
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void *ptr = calc_ptr(a, sbi);
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switch (a->attr_id) {
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case attr_delayed_allocation_blocks:
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return snprintf(buf, PAGE_SIZE, "%llu\n",
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(s64) EXT4_C2B(sbi,
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percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
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case attr_session_write_kbytes:
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return session_write_kbytes_show(a, sbi, buf);
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case attr_lifetime_write_kbytes:
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return lifetime_write_kbytes_show(a, sbi, buf);
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case attr_reserved_clusters:
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return snprintf(buf, PAGE_SIZE, "%llu\n",
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(unsigned long long)
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atomic64_read(&sbi->s_resv_clusters));
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case attr_inode_readahead:
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case attr_pointer_ui:
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if (!ptr)
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return 0;
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return snprintf(buf, PAGE_SIZE, "%u\n",
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*((unsigned int *) ptr));
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case attr_pointer_atomic:
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if (!ptr)
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return 0;
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return snprintf(buf, PAGE_SIZE, "%d\n",
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atomic_read((atomic_t *) ptr));
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case attr_feature:
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return snprintf(buf, PAGE_SIZE, "supported\n");
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}
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return 0;
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}
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static ssize_t ext4_attr_store(struct kobject *kobj,
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struct attribute *attr,
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const char *buf, size_t len)
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{
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struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
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s_kobj);
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struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
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void *ptr = calc_ptr(a, sbi);
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unsigned long t;
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int ret;
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switch (a->attr_id) {
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case attr_reserved_clusters:
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return reserved_clusters_store(a, sbi, buf, len);
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case attr_pointer_ui:
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if (!ptr)
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return 0;
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ret = kstrtoul(skip_spaces(buf), 0, &t);
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if (ret)
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return ret;
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*((unsigned int *) ptr) = t;
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return len;
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case attr_inode_readahead:
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return inode_readahead_blks_store(a, sbi, buf, len);
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case attr_trigger_test_error:
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return trigger_test_error(a, sbi, buf, len);
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}
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return 0;
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}
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static void ext4_sb_release(struct kobject *kobj)
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{
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struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
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s_kobj);
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complete(&sbi->s_kobj_unregister);
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}
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static const struct sysfs_ops ext4_attr_ops = {
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.show = ext4_attr_show,
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.store = ext4_attr_store,
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};
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static struct kobj_type ext4_sb_ktype = {
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.default_attrs = ext4_attrs,
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.sysfs_ops = &ext4_attr_ops,
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.release = ext4_sb_release,
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};
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static struct kobj_type ext4_ktype = {
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.sysfs_ops = &ext4_attr_ops,
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};
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static struct kset ext4_kset = {
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.kobj = {.ktype = &ext4_ktype},
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};
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static struct kobj_type ext4_feat_ktype = {
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.default_attrs = ext4_feat_attrs,
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.sysfs_ops = &ext4_attr_ops,
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};
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static struct kobject ext4_feat = {
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.kset = &ext4_kset,
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};
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#define PROC_FILE_SHOW_DEFN(name) \
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static int name##_open(struct inode *inode, struct file *file) \
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{ \
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return single_open(file, ext4_seq_##name##_show, PDE_DATA(inode)); \
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} \
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\
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static const struct file_operations ext4_seq_##name##_fops = { \
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.open = name##_open, \
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.read = seq_read, \
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.llseek = seq_lseek, \
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.release = single_release, \
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}
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#define PROC_FILE_LIST(name) \
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{ __stringify(name), &ext4_seq_##name##_fops }
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PROC_FILE_SHOW_DEFN(es_shrinker_info);
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PROC_FILE_SHOW_DEFN(options);
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static const struct ext4_proc_files {
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const char *name;
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const struct file_operations *fops;
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} proc_files[] = {
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PROC_FILE_LIST(options),
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PROC_FILE_LIST(es_shrinker_info),
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PROC_FILE_LIST(mb_groups),
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{ NULL, NULL },
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};
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int ext4_register_sysfs(struct super_block *sb)
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{
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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const struct ext4_proc_files *p;
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int err;
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sbi->s_kobj.kset = &ext4_kset;
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init_completion(&sbi->s_kobj_unregister);
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err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, NULL,
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"%s", sb->s_id);
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if (err)
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return err;
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if (ext4_proc_root)
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sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
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if (sbi->s_proc) {
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for (p = proc_files; p->name; p++)
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proc_create_data(p->name, S_IRUGO, sbi->s_proc,
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p->fops, sb);
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}
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return 0;
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}
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void ext4_unregister_sysfs(struct super_block *sb)
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{
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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const struct ext4_proc_files *p;
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if (sbi->s_proc) {
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for (p = proc_files; p->name; p++)
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remove_proc_entry(p->name, sbi->s_proc);
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remove_proc_entry(sb->s_id, ext4_proc_root);
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}
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kobject_del(&sbi->s_kobj);
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}
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int __init ext4_init_sysfs(void)
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{
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int ret;
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kobject_set_name(&ext4_kset.kobj, "ext4");
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ext4_kset.kobj.parent = fs_kobj;
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ret = kset_register(&ext4_kset);
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if (ret)
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return ret;
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ret = kobject_init_and_add(&ext4_feat, &ext4_feat_ktype,
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NULL, "features");
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if (ret)
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kset_unregister(&ext4_kset);
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else
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ext4_proc_root = proc_mkdir(proc_dirname, NULL);
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return ret;
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}
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void ext4_exit_sysfs(void)
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{
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kobject_put(&ext4_feat);
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kset_unregister(&ext4_kset);
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remove_proc_entry(proc_dirname, NULL);
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ext4_proc_root = NULL;
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}
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