Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 698 insertions, 0 deletions

diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
new file mode 100644
index 000000000..923b375e0
--- /dev/null
+++ b/fs/ext4/sysfs.c
@@ -0,0 +1,698 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/sysfs.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Theodore Ts'o (tytso@mit.edu)
+ *
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/proc_fs.h>
+#include <linux/part_stat.h>
+
+#include "ext4.h"
+#include "ext4_jbd2.h"
+
+typedef enum {
+	attr_noop,
+	attr_delayed_allocation_blocks,
+	attr_session_write_kbytes,
+	attr_lifetime_write_kbytes,
+	attr_reserved_clusters,
+	attr_sra_exceeded_retry_limit,
+	attr_inode_readahead,
+	attr_trigger_test_error,
+	attr_first_error_time,
+	attr_last_error_time,
+	attr_clusters_in_group,
+	attr_mb_order,
+	attr_feature,
+	attr_pointer_pi,
+	attr_pointer_ui,
+	attr_pointer_ul,
+	attr_pointer_u64,
+	attr_pointer_u8,
+	attr_pointer_string,
+	attr_pointer_atomic,
+	attr_journal_task,
+	attr_err_report_sec,
+} attr_id_t;
+
+typedef enum {
+	ptr_explicit,
+	ptr_ext4_sb_info_offset,
+	ptr_ext4_super_block_offset,
+} attr_ptr_t;
+
+static const char proc_dirname[] = "fs/ext4";
+static struct proc_dir_entry *ext4_proc_root;
+
+struct ext4_attr {
+	struct attribute attr;
+	short attr_id;
+	short attr_ptr;
+	unsigned short attr_size;
+	union {
+		int offset;
+		void *explicit_ptr;
+	} u;
+};
+
+static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
+{
+	struct super_block *sb = sbi->s_buddy_cache->i_sb;
+
+	return sysfs_emit(buf, "%lu\n",
+			(part_stat_read(sb->s_bdev, sectors[STAT_WRITE]) -
+			 sbi->s_sectors_written_start) >> 1);
+}
+
+static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
+{
+	struct super_block *sb = sbi->s_buddy_cache->i_sb;
+
+	return sysfs_emit(buf, "%llu\n",
+			(unsigned long long)(sbi->s_kbytes_written +
+			((part_stat_read(sb->s_bdev, sectors[STAT_WRITE]) -
+			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
+}
+
+static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
+					  const char *buf, size_t count)
+{
+	unsigned long t;
+	int ret;
+
+	ret = kstrtoul(skip_spaces(buf), 0, &t);
+	if (ret)
+		return ret;
+
+	if (t && (!is_power_of_2(t) || t > 0x40000000))
+		return -EINVAL;
+
+	sbi->s_inode_readahead_blks = t;
+	return count;
+}
+
+static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
+				   const char *buf, size_t count)
+{
+	unsigned long long val;
+	ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
+				 sbi->s_cluster_bits);
+	int ret;
+
+	ret = kstrtoull(skip_spaces(buf), 0, &val);
+	if (ret || val >= clusters || (s64)val < 0)
+		return -EINVAL;
+
+	atomic64_set(&sbi->s_resv_clusters, val);
+	return count;
+}
+
+static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
+				  const char *buf, size_t count)
+{
+	int len = count;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (len && buf[len-1] == '\n')
+		len--;
+
+	if (len)
+		ext4_error(sbi->s_sb, "%.*s", len, buf);
+	return count;
+}
+
+static ssize_t err_report_sec_store(struct ext4_sb_info *sbi,
+				    const char *buf, size_t count)
+{
+	unsigned long t;
+	int ret;
+
+	ret = kstrtoul(skip_spaces(buf), 0, &t);
+	if (ret)
+		return ret;
+
+	/*the maximum time interval must not exceed one year.*/
+	if (t > (365*24*60*60))
+		return -EINVAL;
+
+	if (sbi->s_err_report_sec == t)		/*nothing to do*/
+		goto out;
+	else if (!sbi->s_err_report_sec && t) {
+		timer_setup(&sbi->s_err_report, print_daily_error_info, 0);
+	} else if (sbi->s_err_report_sec && !t) {
+		timer_delete_sync(&sbi->s_err_report);
+		goto out;
+	}
+
+	sbi->s_err_report_sec = t;
+	mod_timer(&sbi->s_err_report, jiffies + secs_to_jiffies(sbi->s_err_report_sec));
+
+out:
+	return count;
+}
+
+static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf)
+{
+	if (!sbi->s_journal)
+		return sysfs_emit(buf, "<none>\n");
+	return sysfs_emit(buf, "%d\n",
+			task_pid_vnr(sbi->s_journal->j_task));
+}
+
+#define EXT4_ATTR(_name,_mode,_id)					\
+static struct ext4_attr ext4_attr_##_name = {				\
+	.attr = {.name = __stringify(_name), .mode = _mode },		\
+	.attr_id = attr_##_id,						\
+}
+
+#define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
+
+#define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
+
+#define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)	\
+static struct ext4_attr ext4_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
+	.attr_id = attr_##_id,					\
+	.attr_ptr = ptr_##_struct##_offset,			\
+	.u = {							\
+		.offset = offsetof(struct _struct, _elname),\
+	},							\
+}
+
+#define EXT4_ATTR_STRING(_name,_mode,_size,_struct,_elname)	\
+static struct ext4_attr ext4_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
+	.attr_id = attr_pointer_string,				\
+	.attr_size = _size,					\
+	.attr_ptr = ptr_##_struct##_offset,			\
+	.u = {							\
+		.offset = offsetof(struct _struct, _elname),\
+	},							\
+}
+
+#define EXT4_RO_ATTR_ES_UI(_name,_elname)				\
+	EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
+
+#define EXT4_RO_ATTR_ES_U8(_name,_elname)				\
+	EXT4_ATTR_OFFSET(_name, 0444, pointer_u8, ext4_super_block, _elname)
+
+#define EXT4_RO_ATTR_ES_U64(_name,_elname)				\
+	EXT4_ATTR_OFFSET(_name, 0444, pointer_u64, ext4_super_block, _elname)
+
+#define EXT4_RO_ATTR_ES_STRING(_name,_elname,_size)			\
+	EXT4_ATTR_STRING(_name, 0444, _size, ext4_super_block, _elname)
+
+#define EXT4_RW_ATTR_SBI_PI(_name,_elname)      \
+	EXT4_ATTR_OFFSET(_name, 0644, pointer_pi, ext4_sb_info, _elname)
+
+#define EXT4_RW_ATTR_SBI_UI(_name,_elname)	\
+	EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
+
+#define EXT4_RW_ATTR_SBI_UL(_name,_elname)	\
+	EXT4_ATTR_OFFSET(_name, 0644, pointer_ul, ext4_sb_info, _elname)
+
+#define EXT4_RO_ATTR_SBI_ATOMIC(_name,_elname)	\
+	EXT4_ATTR_OFFSET(_name, 0444, pointer_atomic, ext4_sb_info, _elname)
+
+#define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
+static struct ext4_attr ext4_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
+	.attr_id = attr_##_id,					\
+	.attr_ptr = ptr_explicit,				\
+	.u = {							\
+		.explicit_ptr = _ptr,				\
+	},							\
+}
+
+#define ATTR_LIST(name) &ext4_attr_##name.attr
+
+EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
+EXT4_ATTR_FUNC(session_write_kbytes, 0444);
+EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
+EXT4_ATTR_FUNC(reserved_clusters, 0644);
+EXT4_ATTR_FUNC(sra_exceeded_retry_limit, 0444);
+
+EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
+		 ext4_sb_info, s_inode_readahead_blks);
+EXT4_ATTR_OFFSET(mb_group_prealloc, 0644, clusters_in_group,
+		 ext4_sb_info, s_mb_group_prealloc);
+EXT4_ATTR_OFFSET(mb_best_avail_max_trim_order, 0644, mb_order,
+		 ext4_sb_info, s_mb_best_avail_max_trim_order);
+EXT4_ATTR_OFFSET(err_report_sec, 0644, err_report_sec, ext4_sb_info, s_err_report_sec);
+EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
+EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
+EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
+EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
+EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
+EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
+EXT4_RW_ATTR_SBI_UI(mb_max_linear_groups, s_mb_max_linear_groups);
+EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
+EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
+EXT4_RW_ATTR_SBI_PI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(err_ratelimit_burst, s_err_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_PI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_PI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
+#ifdef CONFIG_EXT4_DEBUG
+EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail);
+#endif
+EXT4_RO_ATTR_SBI_ATOMIC(warning_count, s_warning_count);
+EXT4_RO_ATTR_SBI_ATOMIC(msg_count, s_msg_count);
+EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
+EXT4_RO_ATTR_ES_U8(first_error_errcode, s_first_error_errcode);
+EXT4_RO_ATTR_ES_U8(last_error_errcode, s_last_error_errcode);
+EXT4_RO_ATTR_ES_UI(first_error_ino, s_first_error_ino);
+EXT4_RO_ATTR_ES_UI(last_error_ino, s_last_error_ino);
+EXT4_RO_ATTR_ES_U64(first_error_block, s_first_error_block);
+EXT4_RO_ATTR_ES_U64(last_error_block, s_last_error_block);
+EXT4_RO_ATTR_ES_UI(first_error_line, s_first_error_line);
+EXT4_RO_ATTR_ES_UI(last_error_line, s_last_error_line);
+EXT4_RO_ATTR_ES_STRING(first_error_func, s_first_error_func, 32);
+EXT4_RO_ATTR_ES_STRING(last_error_func, s_last_error_func, 32);
+EXT4_ATTR(first_error_time, 0444, first_error_time);
+EXT4_ATTR(last_error_time, 0444, last_error_time);
+EXT4_ATTR(journal_task, 0444, journal_task);
+EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch);
+EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit);
+EXT4_RW_ATTR_SBI_UL(last_trim_minblks, s_last_trim_minblks);
+EXT4_RW_ATTR_SBI_UI(sb_update_sec, s_sb_update_sec);
+EXT4_RW_ATTR_SBI_UI(sb_update_kb, s_sb_update_kb);
+
+static unsigned int old_bump_val = 128;
+EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
+
+static struct attribute *ext4_attrs[] = {
+	ATTR_LIST(delayed_allocation_blocks),
+	ATTR_LIST(session_write_kbytes),
+	ATTR_LIST(lifetime_write_kbytes),
+	ATTR_LIST(reserved_clusters),
+	ATTR_LIST(sra_exceeded_retry_limit),
+	ATTR_LIST(inode_readahead_blks),
+	ATTR_LIST(inode_goal),
+	ATTR_LIST(mb_stats),
+	ATTR_LIST(mb_max_to_scan),
+	ATTR_LIST(mb_min_to_scan),
+	ATTR_LIST(mb_order2_req),
+	ATTR_LIST(mb_stream_req),
+	ATTR_LIST(mb_group_prealloc),
+	ATTR_LIST(mb_max_linear_groups),
+	ATTR_LIST(max_writeback_mb_bump),
+	ATTR_LIST(extent_max_zeroout_kb),
+	ATTR_LIST(trigger_fs_error),
+	ATTR_LIST(err_ratelimit_interval_ms),
+	ATTR_LIST(err_ratelimit_burst),
+	ATTR_LIST(warning_ratelimit_interval_ms),
+	ATTR_LIST(warning_ratelimit_burst),
+	ATTR_LIST(msg_ratelimit_interval_ms),
+	ATTR_LIST(msg_ratelimit_burst),
+	ATTR_LIST(mb_best_avail_max_trim_order),
+	ATTR_LIST(errors_count),
+	ATTR_LIST(warning_count),
+	ATTR_LIST(msg_count),
+	ATTR_LIST(first_error_ino),
+	ATTR_LIST(last_error_ino),
+	ATTR_LIST(first_error_block),
+	ATTR_LIST(last_error_block),
+	ATTR_LIST(first_error_line),
+	ATTR_LIST(last_error_line),
+	ATTR_LIST(first_error_func),
+	ATTR_LIST(last_error_func),
+	ATTR_LIST(first_error_errcode),
+	ATTR_LIST(last_error_errcode),
+	ATTR_LIST(first_error_time),
+	ATTR_LIST(last_error_time),
+	ATTR_LIST(journal_task),
+#ifdef CONFIG_EXT4_DEBUG
+	ATTR_LIST(simulate_fail),
+#endif
+	ATTR_LIST(mb_prefetch),
+	ATTR_LIST(mb_prefetch_limit),
+	ATTR_LIST(last_trim_minblks),
+	ATTR_LIST(sb_update_sec),
+	ATTR_LIST(sb_update_kb),
+	ATTR_LIST(err_report_sec),
+	NULL,
+};
+ATTRIBUTE_GROUPS(ext4);
+
+/* Features this copy of ext4 supports */
+EXT4_ATTR_FEATURE(lazy_itable_init);
+EXT4_ATTR_FEATURE(batched_discard);
+EXT4_ATTR_FEATURE(meta_bg_resize);
+#ifdef CONFIG_FS_ENCRYPTION
+EXT4_ATTR_FEATURE(encryption);
+EXT4_ATTR_FEATURE(test_dummy_encryption_v2);
+#endif
+#if IS_ENABLED(CONFIG_UNICODE)
+EXT4_ATTR_FEATURE(casefold);
+#endif
+#ifdef CONFIG_FS_VERITY
+EXT4_ATTR_FEATURE(verity);
+#endif
+EXT4_ATTR_FEATURE(metadata_csum_seed);
+EXT4_ATTR_FEATURE(fast_commit);
+#if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
+EXT4_ATTR_FEATURE(encrypted_casefold);
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+EXT4_ATTR_FEATURE(blocksize_gt_pagesize);
+#endif
+
+static struct attribute *ext4_feat_attrs[] = {
+	ATTR_LIST(lazy_itable_init),
+	ATTR_LIST(batched_discard),
+	ATTR_LIST(meta_bg_resize),
+#ifdef CONFIG_FS_ENCRYPTION
+	ATTR_LIST(encryption),
+	ATTR_LIST(test_dummy_encryption_v2),
+#endif
+#if IS_ENABLED(CONFIG_UNICODE)
+	ATTR_LIST(casefold),
+#endif
+#ifdef CONFIG_FS_VERITY
+	ATTR_LIST(verity),
+#endif
+	ATTR_LIST(metadata_csum_seed),
+	ATTR_LIST(fast_commit),
+#if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
+	ATTR_LIST(encrypted_casefold),
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	ATTR_LIST(blocksize_gt_pagesize),
+#endif
+	NULL,
+};
+ATTRIBUTE_GROUPS(ext4_feat);
+
+static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
+{
+	switch (a->attr_ptr) {
+	case ptr_explicit:
+		return a->u.explicit_ptr;
+	case ptr_ext4_sb_info_offset:
+		return (void *) (((char *) sbi) + a->u.offset);
+	case ptr_ext4_super_block_offset:
+		return (void *) (((char *) sbi->s_es) + a->u.offset);
+	}
+	return NULL;
+}
+
+static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
+{
+	return sysfs_emit(buf, "%lld\n",
+			((time64_t)hi << 32) + le32_to_cpu(lo));
+}
+
+#define print_tstamp(buf, es, tstamp) \
+	__print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
+
+static ssize_t ext4_generic_attr_show(struct ext4_attr *a,
+				      struct ext4_sb_info *sbi, char *buf)
+{
+	void *ptr = calc_ptr(a, sbi);
+
+	if (!ptr)
+		return 0;
+
+	switch (a->attr_id) {
+	case attr_inode_readahead:
+	case attr_clusters_in_group:
+	case attr_mb_order:
+	case attr_pointer_pi:
+	case attr_pointer_ui:
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			return sysfs_emit(buf, "%u\n", le32_to_cpup(ptr));
+		return sysfs_emit(buf, "%u\n", *((unsigned int *) ptr));
+	case attr_pointer_ul:
+	case attr_err_report_sec:
+		return sysfs_emit(buf, "%lu\n", *((unsigned long *) ptr));
+	case attr_pointer_u8:
+		return sysfs_emit(buf, "%u\n", *((unsigned char *) ptr));
+	case attr_pointer_u64:
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			return sysfs_emit(buf, "%llu\n", le64_to_cpup(ptr));
+		return sysfs_emit(buf, "%llu\n", *((unsigned long long *) ptr));
+	case attr_pointer_string:
+		return sysfs_emit(buf, "%.*s\n", a->attr_size, (char *) ptr);
+	case attr_pointer_atomic:
+		return sysfs_emit(buf, "%d\n", atomic_read((atomic_t *) ptr));
+	}
+	return 0;
+}
+
+static ssize_t ext4_attr_show(struct kobject *kobj,
+			      struct attribute *attr, char *buf)
+{
+	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+						s_kobj);
+	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
+
+	switch (a->attr_id) {
+	case attr_delayed_allocation_blocks:
+		return sysfs_emit(buf, "%llu\n",
+				(s64) EXT4_C2B(sbi,
+		       percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
+	case attr_session_write_kbytes:
+		return session_write_kbytes_show(sbi, buf);
+	case attr_lifetime_write_kbytes:
+		return lifetime_write_kbytes_show(sbi, buf);
+	case attr_reserved_clusters:
+		return sysfs_emit(buf, "%llu\n",
+				(unsigned long long)
+				atomic64_read(&sbi->s_resv_clusters));
+	case attr_sra_exceeded_retry_limit:
+		return sysfs_emit(buf, "%llu\n",
+				(unsigned long long)
+			percpu_counter_sum(&sbi->s_sra_exceeded_retry_limit));
+	case attr_feature:
+		return sysfs_emit(buf, "supported\n");
+	case attr_first_error_time:
+		return print_tstamp(buf, sbi->s_es, s_first_error_time);
+	case attr_last_error_time:
+		return print_tstamp(buf, sbi->s_es, s_last_error_time);
+	case attr_journal_task:
+		return journal_task_show(sbi, buf);
+	default:
+		return ext4_generic_attr_show(a, sbi, buf);
+	}
+}
+
+static ssize_t ext4_generic_attr_store(struct ext4_attr *a,
+				       struct ext4_sb_info *sbi,
+				       const char *buf, size_t len)
+{
+	int ret;
+	unsigned int t;
+	unsigned long lt;
+	void *ptr = calc_ptr(a, sbi);
+
+	if (!ptr)
+		return 0;
+
+	switch (a->attr_id) {
+	case attr_pointer_pi:
+		ret = kstrtouint(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if ((int)t < 0)
+			return -EINVAL;
+		*((unsigned int *) ptr) = t;
+		return len;
+	case attr_pointer_ui:
+		ret = kstrtouint(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			*((__le32 *) ptr) = cpu_to_le32(t);
+		else
+			*((unsigned int *) ptr) = t;
+		return len;
+	case attr_mb_order:
+		ret = kstrtouint(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if (t > 64)
+			return -EINVAL;
+		*((unsigned int *) ptr) = t;
+		return len;
+	case attr_clusters_in_group:
+		ret = kstrtouint(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if (t > sbi->s_clusters_per_group)
+			return -EINVAL;
+		*((unsigned int *) ptr) = t;
+		return len;
+	case attr_pointer_ul:
+		ret = kstrtoul(skip_spaces(buf), 0, &lt);
+		if (ret)
+			return ret;
+		*((unsigned long *) ptr) = lt;
+		return len;
+	}
+	return 0;
+}
+
+static ssize_t ext4_attr_store(struct kobject *kobj,
+			       struct attribute *attr,
+			       const char *buf, size_t len)
+{
+	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+						s_kobj);
+	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
+
+	switch (a->attr_id) {
+	case attr_reserved_clusters:
+		return reserved_clusters_store(sbi, buf, len);
+	case attr_inode_readahead:
+		return inode_readahead_blks_store(sbi, buf, len);
+	case attr_trigger_test_error:
+		return trigger_test_error(sbi, buf, len);
+	case attr_err_report_sec:
+		return err_report_sec_store(sbi, buf, len);
+	default:
+		return ext4_generic_attr_store(a, sbi, buf, len);
+	}
+}
+
+static void ext4_sb_release(struct kobject *kobj)
+{
+	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+						s_kobj);
+	complete(&sbi->s_kobj_unregister);
+}
+
+static void ext4_feat_release(struct kobject *kobj)
+{
+	kfree(kobj);
+}
+
+static const struct sysfs_ops ext4_attr_ops = {
+	.show	= ext4_attr_show,
+	.store	= ext4_attr_store,
+};
+
+static const struct kobj_type ext4_sb_ktype = {
+	.default_groups = ext4_groups,
+	.sysfs_ops	= &ext4_attr_ops,
+	.release	= ext4_sb_release,
+};
+
+static const struct kobj_type ext4_feat_ktype = {
+	.default_groups = ext4_feat_groups,
+	.sysfs_ops	= &ext4_attr_ops,
+	.release	= ext4_feat_release,
+};
+
+void ext4_notify_error_sysfs(struct ext4_sb_info *sbi)
+{
+	mutex_lock(&sbi->s_error_notify_mutex);
+	if (sbi->s_kobj.state_in_sysfs)
+		sysfs_notify(&sbi->s_kobj, NULL, "errors_count");
+	mutex_unlock(&sbi->s_error_notify_mutex);
+}
+
+static struct kobject *ext4_root;
+
+static struct kobject *ext4_feat;
+
+int ext4_register_sysfs(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int err;
+
+	init_completion(&sbi->s_kobj_unregister);
+	mutex_lock(&sbi->s_error_notify_mutex);
+	err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
+				   "%s", sb->s_id);
+	mutex_unlock(&sbi->s_error_notify_mutex);
+	if (err) {
+		kobject_put(&sbi->s_kobj);
+		wait_for_completion(&sbi->s_kobj_unregister);
+		return err;
+	}
+
+	if (ext4_proc_root)
+		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
+	if (sbi->s_proc) {
+		proc_create_single_data("options", S_IRUGO, sbi->s_proc,
+				ext4_seq_options_show, sb);
+		proc_create_single_data("es_shrinker_info", S_IRUGO,
+				sbi->s_proc, ext4_seq_es_shrinker_info_show,
+				sb);
+		proc_create_single_data("fc_info", 0444, sbi->s_proc,
+					ext4_fc_info_show, sb);
+		proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
+				&ext4_mb_seq_groups_ops, sb);
+		proc_create_single_data("mb_stats", 0444, sbi->s_proc,
+				ext4_seq_mb_stats_show, sb);
+		proc_create_seq_data("mb_structs_summary", 0444, sbi->s_proc,
+				&ext4_mb_seq_structs_summary_ops, sb);
+	}
+	return 0;
+}
+
+void ext4_unregister_sysfs(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (sbi->s_proc)
+		remove_proc_subtree(sb->s_id, ext4_proc_root);
+
+	mutex_lock(&sbi->s_error_notify_mutex);
+	kobject_del(&sbi->s_kobj);
+	mutex_unlock(&sbi->s_error_notify_mutex);
+}
+
+int __init ext4_init_sysfs(void)
+{
+	int ret;
+
+	ext4_root = kobject_create_and_add("ext4", fs_kobj);
+	if (!ext4_root)
+		return -ENOMEM;
+
+	ext4_feat = kzalloc_obj(*ext4_feat);
+	if (!ext4_feat) {
+		ret = -ENOMEM;
+		goto root_err;
+	}
+
+	ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
+				   ext4_root, "features");
+	if (ret)
+		goto feat_err;
+
+	ext4_proc_root = proc_mkdir(proc_dirname, NULL);
+	return ret;
+
+feat_err:
+	kobject_put(ext4_feat);
+	ext4_feat = NULL;
+root_err:
+	kobject_put(ext4_root);
+	ext4_root = NULL;
+	return ret;
+}
+
+void ext4_exit_sysfs(void)
+{
+	kobject_put(ext4_feat);
+	ext4_feat = NULL;
+	kobject_put(ext4_root);
+	ext4_root = NULL;
+	remove_proc_entry(proc_dirname, NULL);
+	ext4_proc_root = NULL;
+}
+