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, 943 insertions, 0 deletions

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
new file mode 100644
index 000000000..a9ea36ba2
--- /dev/null
+++ b/fs/exfat/super.c
@@ -0,0 +1,943 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/mount.h>
+#include <linux/cred.h>
+#include <linux/statfs.h>
+#include <linux/seq_file.h>
+#include <linux/blkdev.h>
+#include <linux/fs_struct.h>
+#include <linux/iversion.h>
+#include <linux/nls.h>
+#include <linux/buffer_head.h>
+#include <linux/magic.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+static char exfat_default_iocharset[] = CONFIG_EXFAT_DEFAULT_IOCHARSET;
+static struct kmem_cache *exfat_inode_cachep;
+
+static void exfat_free_iocharset(struct exfat_sb_info *sbi)
+{
+	if (sbi->options.iocharset != exfat_default_iocharset)
+		kfree(sbi->options.iocharset);
+}
+
+static void exfat_set_iocharset(struct exfat_mount_options *opts,
+				char *iocharset)
+{
+	opts->iocharset = iocharset;
+	if (!strcmp(opts->iocharset, "utf8"))
+		opts->utf8 = 1;
+	else
+		opts->utf8 = 0;
+}
+
+static void exfat_put_super(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	mutex_lock(&sbi->s_lock);
+	exfat_clear_volume_dirty(sb);
+	exfat_free_bitmap(sbi);
+	brelse(sbi->boot_bh);
+	mutex_unlock(&sbi->s_lock);
+}
+
+static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	buf->f_type = sb->s_magic;
+	buf->f_bsize = sbi->cluster_size;
+	buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
+	buf->f_bfree = buf->f_blocks - sbi->used_clusters;
+	buf->f_bavail = buf->f_bfree;
+	buf->f_fsid = u64_to_fsid(id);
+	/* Unicode utf16 255 characters */
+	buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
+	return 0;
+}
+
+static int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flags)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
+
+	/* retain persistent-flags */
+	new_flags |= sbi->vol_flags_persistent;
+
+	/* flags are not changed */
+	if (sbi->vol_flags == new_flags)
+		return 0;
+
+	sbi->vol_flags = new_flags;
+
+	/* skip updating volume dirty flag,
+	 * if this volume has been mounted with read-only
+	 */
+	if (sb_rdonly(sb))
+		return 0;
+
+	p_boot->vol_flags = cpu_to_le16(new_flags);
+
+	set_buffer_uptodate(sbi->boot_bh);
+	mark_buffer_dirty(sbi->boot_bh);
+
+	__sync_dirty_buffer(sbi->boot_bh, REQ_SYNC | REQ_FUA | REQ_PREFLUSH);
+
+	return 0;
+}
+
+int exfat_set_volume_dirty(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	return exfat_set_vol_flags(sb, sbi->vol_flags | VOLUME_DIRTY);
+}
+
+int exfat_clear_volume_dirty(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	return exfat_set_vol_flags(sb, sbi->vol_flags & ~VOLUME_DIRTY);
+}
+
+static int exfat_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_mount_options *opts = &sbi->options;
+
+	/* Show partition info */
+	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
+		seq_printf(m, ",uid=%u",
+				from_kuid_munged(&init_user_ns, opts->fs_uid));
+	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
+		seq_printf(m, ",gid=%u",
+				from_kgid_munged(&init_user_ns, opts->fs_gid));
+	seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
+	if (opts->allow_utime)
+		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
+	if (opts->utf8)
+		seq_puts(m, ",iocharset=utf8");
+	else if (sbi->nls_io)
+		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
+	if (opts->errors == EXFAT_ERRORS_CONT)
+		seq_puts(m, ",errors=continue");
+	else if (opts->errors == EXFAT_ERRORS_PANIC)
+		seq_puts(m, ",errors=panic");
+	else
+		seq_puts(m, ",errors=remount-ro");
+	if (opts->discard)
+		seq_puts(m, ",discard");
+	if (opts->keep_last_dots)
+		seq_puts(m, ",keep_last_dots");
+	if (opts->sys_tz)
+		seq_puts(m, ",sys_tz");
+	else if (opts->time_offset)
+		seq_printf(m, ",time_offset=%d", opts->time_offset);
+	if (opts->zero_size_dir)
+		seq_puts(m, ",zero_size_dir");
+	return 0;
+}
+
+int exfat_force_shutdown(struct super_block *sb, u32 flags)
+{
+	int ret;
+	struct exfat_sb_info *sbi = sb->s_fs_info;
+	struct exfat_mount_options *opts = &sbi->options;
+
+	if (exfat_forced_shutdown(sb))
+		return 0;
+
+	switch (flags) {
+	case EXFAT_GOING_DOWN_DEFAULT:
+	case EXFAT_GOING_DOWN_FULLSYNC:
+		ret = bdev_freeze(sb->s_bdev);
+		if (ret)
+			return ret;
+		bdev_thaw(sb->s_bdev);
+		set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags);
+		break;
+	case EXFAT_GOING_DOWN_NOSYNC:
+		set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (opts->discard)
+		opts->discard = 0;
+	return 0;
+}
+
+static void exfat_shutdown(struct super_block *sb)
+{
+	exfat_force_shutdown(sb, EXFAT_GOING_DOWN_NOSYNC);
+}
+
+static struct inode *exfat_alloc_inode(struct super_block *sb)
+{
+	struct exfat_inode_info *ei;
+
+	ei = alloc_inode_sb(sb, exfat_inode_cachep, GFP_NOFS);
+	if (!ei)
+		return NULL;
+
+	return &ei->vfs_inode;
+}
+
+static void exfat_free_inode(struct inode *inode)
+{
+	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
+}
+
+static const struct super_operations exfat_sops = {
+	.alloc_inode	= exfat_alloc_inode,
+	.free_inode	= exfat_free_inode,
+	.write_inode	= exfat_write_inode,
+	.evict_inode	= exfat_evict_inode,
+	.put_super	= exfat_put_super,
+	.statfs		= exfat_statfs,
+	.show_options	= exfat_show_options,
+	.shutdown	= exfat_shutdown,
+};
+
+enum {
+	Opt_uid,
+	Opt_gid,
+	Opt_umask,
+	Opt_dmask,
+	Opt_fmask,
+	Opt_allow_utime,
+	Opt_charset,
+	Opt_errors,
+	Opt_discard,
+	Opt_keep_last_dots,
+	Opt_sys_tz,
+	Opt_time_offset,
+	Opt_zero_size_dir,
+
+	/* Deprecated options */
+	Opt_utf8,
+	Opt_debug,
+	Opt_namecase,
+	Opt_codepage,
+};
+
+static const struct constant_table exfat_param_enums[] = {
+	{ "continue",		EXFAT_ERRORS_CONT },
+	{ "panic",		EXFAT_ERRORS_PANIC },
+	{ "remount-ro",		EXFAT_ERRORS_RO },
+	{}
+};
+
+static const struct fs_parameter_spec exfat_parameters[] = {
+	fsparam_uid("uid",			Opt_uid),
+	fsparam_gid("gid",			Opt_gid),
+	fsparam_u32oct("umask",			Opt_umask),
+	fsparam_u32oct("dmask",			Opt_dmask),
+	fsparam_u32oct("fmask",			Opt_fmask),
+	fsparam_u32oct("allow_utime",		Opt_allow_utime),
+	fsparam_string("iocharset",		Opt_charset),
+	fsparam_enum("errors",			Opt_errors, exfat_param_enums),
+	fsparam_flag_no("discard",		Opt_discard),
+	fsparam_flag("keep_last_dots",		Opt_keep_last_dots),
+	fsparam_flag("sys_tz",			Opt_sys_tz),
+	fsparam_s32("time_offset",		Opt_time_offset),
+	fsparam_flag_no("zero_size_dir",	Opt_zero_size_dir),
+	__fsparam(NULL, "utf8",			Opt_utf8, fs_param_deprecated,
+		  NULL),
+	__fsparam(NULL, "debug",		Opt_debug, fs_param_deprecated,
+		  NULL),
+	__fsparam(fs_param_is_u32, "namecase",	Opt_namecase,
+		  fs_param_deprecated, NULL),
+	__fsparam(fs_param_is_u32, "codepage",	Opt_codepage,
+		  fs_param_deprecated, NULL),
+	{}
+};
+
+static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct exfat_sb_info *sbi = fc->s_fs_info;
+	struct exfat_mount_options *opts = &sbi->options;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, exfat_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_uid:
+		opts->fs_uid = result.uid;
+		break;
+	case Opt_gid:
+		opts->fs_gid = result.gid;
+		break;
+	case Opt_umask:
+		opts->fs_fmask = result.uint_32;
+		opts->fs_dmask = result.uint_32;
+		break;
+	case Opt_dmask:
+		opts->fs_dmask = result.uint_32;
+		break;
+	case Opt_fmask:
+		opts->fs_fmask = result.uint_32;
+		break;
+	case Opt_allow_utime:
+		opts->allow_utime = result.uint_32 & 0022;
+		break;
+	case Opt_charset:
+		exfat_free_iocharset(sbi);
+		exfat_set_iocharset(opts, param->string);
+		param->string = NULL;
+		break;
+	case Opt_errors:
+		opts->errors = result.uint_32;
+		break;
+	case Opt_discard:
+		opts->discard = !result.negated;
+		break;
+	case Opt_keep_last_dots:
+		opts->keep_last_dots = 1;
+		break;
+	case Opt_sys_tz:
+		opts->sys_tz = 1;
+		break;
+	case Opt_time_offset:
+		/*
+		 * Make the limit 24 just in case someone invents something
+		 * unusual.
+		 */
+		if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
+			return -EINVAL;
+		opts->time_offset = result.int_32;
+		break;
+	case Opt_zero_size_dir:
+		opts->zero_size_dir = !result.negated;
+		break;
+	case Opt_utf8:
+	case Opt_debug:
+	case Opt_namecase:
+	case Opt_codepage:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void exfat_hash_init(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int i;
+
+	spin_lock_init(&sbi->inode_hash_lock);
+	for (i = 0; i < EXFAT_HASH_SIZE; i++)
+		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
+}
+
+static int exfat_read_root(struct inode *inode, struct exfat_chain *root_clu)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	int num_subdirs;
+
+	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+	ei->entry = -1;
+	ei->start_clu = sbi->root_dir;
+	ei->flags = ALLOC_FAT_CHAIN;
+	ei->type = TYPE_DIR;
+	ei->version = 0;
+	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
+	ei->hint_stat.eidx = 0;
+	ei->hint_stat.clu = sbi->root_dir;
+	ei->hint_femp.eidx = EXFAT_HINT_NONE;
+
+	i_size_write(inode, exfat_cluster_to_bytes(sbi, root_clu->size));
+
+	num_subdirs = exfat_count_dir_entries(sb, root_clu);
+	if (num_subdirs < 0)
+		return -EIO;
+	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
+
+	inode->i_uid = sbi->options.fs_uid;
+	inode->i_gid = sbi->options.fs_gid;
+	inode_inc_iversion(inode);
+	inode->i_generation = 0;
+	inode->i_mode = exfat_make_mode(sbi, EXFAT_ATTR_SUBDIR, 0777);
+	inode->i_op = &exfat_dir_inode_operations;
+	inode->i_fop = &exfat_dir_operations;
+
+	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
+	ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
+
+	exfat_save_attr(inode, EXFAT_ATTR_SUBDIR);
+	ei->i_crtime = simple_inode_init_ts(inode);
+	exfat_truncate_inode_atime(inode);
+	return 0;
+}
+
+static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	if (!is_power_of_2(logical_sect)) {
+		exfat_err(sb, "bogus logical sector size %u", logical_sect);
+		return -EIO;
+	}
+
+	if (logical_sect < sb->s_blocksize) {
+		exfat_err(sb, "logical sector size too small for device (logical sector size = %u)",
+			  logical_sect);
+		return -EIO;
+	}
+
+	if (logical_sect > sb->s_blocksize) {
+		brelse(sbi->boot_bh);
+		sbi->boot_bh = NULL;
+
+		if (!sb_set_blocksize(sb, logical_sect)) {
+			exfat_err(sb, "unable to set blocksize %u",
+				  logical_sect);
+			return -EIO;
+		}
+		sbi->boot_bh = sb_bread(sb, 0);
+		if (!sbi->boot_bh) {
+			exfat_err(sb, "unable to read boot sector (logical sector size = %lu)",
+				  sb->s_blocksize);
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+static int exfat_read_boot_sector(struct super_block *sb)
+{
+	struct boot_sector *p_boot;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	/* set block size to read super block */
+	if (!sb_min_blocksize(sb, 512)) {
+		exfat_err(sb, "unable to set blocksize");
+		return -EINVAL;
+	}
+
+	/* read boot sector */
+	sbi->boot_bh = sb_bread(sb, 0);
+	if (!sbi->boot_bh) {
+		exfat_err(sb, "unable to read boot sector");
+		return -EIO;
+	}
+	p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
+
+	/* check the validity of BOOT */
+	if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
+		exfat_err(sb, "invalid boot record signature");
+		return -EINVAL;
+	}
+
+	if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
+		exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
+		return -EINVAL;
+	}
+
+	/*
+	 * must_be_zero field must be filled with zero to prevent mounting
+	 * from FAT volume.
+	 */
+	if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
+		return -EINVAL;
+
+	if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
+		exfat_err(sb, "bogus number of FAT structure");
+		return -EINVAL;
+	}
+
+	/*
+	 * sect_size_bits could be at least 9 and at most 12.
+	 */
+	if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
+	    p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
+		exfat_err(sb, "bogus sector size bits : %u",
+				p_boot->sect_size_bits);
+		return -EINVAL;
+	}
+
+	/*
+	 * sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
+	 */
+	if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
+		exfat_err(sb, "bogus sectors bits per cluster : %u",
+				p_boot->sect_per_clus_bits);
+		return -EINVAL;
+	}
+
+	sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;
+	sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;
+	sbi->cluster_size_bits = p_boot->sect_per_clus_bits +
+		p_boot->sect_size_bits;
+	sbi->cluster_size = 1 << sbi->cluster_size_bits;
+	sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);
+	sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);
+	sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset);
+	if (p_boot->num_fats == 2)
+		sbi->FAT2_start_sector += sbi->num_FAT_sectors;
+	sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
+	sbi->data_start_bytes = sbi->data_start_sector << p_boot->sect_size_bits;
+	sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
+	/* because the cluster index starts with 2 */
+	sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
+		EXFAT_RESERVED_CLUSTERS;
+
+	sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
+	sbi->dentries_per_clu = 1 <<
+		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
+
+	sbi->vol_flags = le16_to_cpu(p_boot->vol_flags);
+	sbi->vol_flags_persistent = sbi->vol_flags & (VOLUME_DIRTY | MEDIA_FAILURE);
+	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
+
+	/* check consistencies */
+	if ((u64)sbi->num_FAT_sectors << p_boot->sect_size_bits <
+	    (u64)sbi->num_clusters * 4) {
+		exfat_err(sb, "bogus fat length");
+		return -EINVAL;
+	}
+
+	if (sbi->data_start_sector <
+	    (u64)sbi->FAT1_start_sector +
+	    (u64)sbi->num_FAT_sectors * p_boot->num_fats) {
+		exfat_err(sb, "bogus data start sector");
+		return -EINVAL;
+	}
+
+	if (sbi->vol_flags & VOLUME_DIRTY)
+		exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
+	if (sbi->vol_flags & MEDIA_FAILURE)
+		exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
+
+	/*
+	 * Set to the max possible volume size for this volume's cluster size so
+	 * that any integer overflow from bytes to cluster size conversion is
+	 * checked in inode_newsize_ok(). Clamped to MAX_LFS_FILESIZE for 32-bit
+	 * machines.
+	 */
+	sb->s_maxbytes = min(MAX_LFS_FILESIZE,
+			     exfat_cluster_to_bytes(sbi, (loff_t)EXFAT_MAX_NUM_CLUSTER));
+
+	/* check logical sector size */
+	if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits))
+		return -EIO;
+
+	return 0;
+}
+
+static int exfat_verify_boot_region(struct super_block *sb)
+{
+	struct buffer_head *bh = NULL;
+	u32 chksum = 0;
+	__le32 *p_sig, *p_chksum;
+	int sn, i;
+
+	/* read boot sector sub-regions */
+	for (sn = 0; sn < 11; sn++) {
+		bh = sb_bread(sb, sn);
+		if (!bh)
+			return -EIO;
+
+		if (sn != 0 && sn <= 8) {
+			/* extended boot sector sub-regions */
+			p_sig = (__le32 *)&bh->b_data[sb->s_blocksize - 4];
+			if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE)
+				exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x",
+					   sn, le32_to_cpu(*p_sig));
+		}
+
+		chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
+			chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
+		brelse(bh);
+	}
+
+	/* boot checksum sub-regions */
+	bh = sb_bread(sb, sn);
+	if (!bh)
+		return -EIO;
+
+	for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
+		p_chksum = (__le32 *)&bh->b_data[i];
+		if (le32_to_cpu(*p_chksum) != chksum) {
+			exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)",
+				  le32_to_cpu(*p_chksum), chksum);
+			brelse(bh);
+			return -EINVAL;
+		}
+	}
+	brelse(bh);
+	return 0;
+}
+
+/* mount the file system volume */
+static int __exfat_fill_super(struct super_block *sb,
+		struct exfat_chain *root_clu)
+{
+	int ret;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	ret = exfat_read_boot_sector(sb);
+	if (ret) {
+		exfat_err(sb, "failed to read boot sector");
+		goto free_bh;
+	}
+
+	ret = exfat_verify_boot_region(sb);
+	if (ret) {
+		exfat_err(sb, "invalid boot region");
+		goto free_bh;
+	}
+
+	/*
+	 * Call exfat_count_num_cluster() before searching for up-case and
+	 * bitmap directory entries to avoid infinite loop if they are missing
+	 * and the cluster chain includes a loop.
+	 */
+	exfat_chain_set(root_clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+	ret = exfat_count_num_clusters(sb, root_clu, &root_clu->size);
+	if (ret) {
+		exfat_err(sb, "failed to count the number of clusters in root");
+		goto free_bh;
+	}
+
+	ret = exfat_create_upcase_table(sb);
+	if (ret) {
+		exfat_err(sb, "failed to load upcase table");
+		goto free_bh;
+	}
+
+	ret = exfat_load_bitmap(sb);
+	if (ret) {
+		exfat_err(sb, "failed to load alloc-bitmap");
+		goto free_bh;
+	}
+
+	if (!exfat_test_bitmap(sb, sbi->root_dir)) {
+		exfat_warn(sb, "failed to test first cluster bit of root dir(%u)",
+			   sbi->root_dir);
+		/*
+		 * The first cluster bit of the root directory should never
+		 * be unset except when storage is corrupted. This bit is
+		 * set to allow operations after mount.
+		 */
+		exfat_set_bitmap(sb, sbi->root_dir, false);
+	}
+
+	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
+	if (ret) {
+		exfat_err(sb, "failed to scan clusters");
+		goto free_alloc_bitmap;
+	}
+
+	return 0;
+
+free_alloc_bitmap:
+	exfat_free_bitmap(sbi);
+free_bh:
+	brelse(sbi->boot_bh);
+	return ret;
+}
+
+static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct exfat_sb_info *sbi = sb->s_fs_info;
+	struct exfat_mount_options *opts = &sbi->options;
+	struct inode *root_inode;
+	struct exfat_chain root_clu;
+	int err;
+
+	if (opts->allow_utime == (unsigned short)-1)
+		opts->allow_utime = ~opts->fs_dmask & 0022;
+
+	if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
+		exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
+		opts->discard = 0;
+	}
+
+	sb->s_flags |= SB_NODIRATIME;
+	sb->s_magic = EXFAT_SUPER_MAGIC;
+	sb->s_op = &exfat_sops;
+
+	sb->s_time_gran = 10 * NSEC_PER_MSEC;
+	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
+	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
+
+	err = __exfat_fill_super(sb, &root_clu);
+	if (err) {
+		exfat_err(sb, "failed to recognize exfat type");
+		goto check_nls_io;
+	}
+
+	/* set up enough so that it can read an inode */
+	exfat_hash_init(sb);
+
+	if (sbi->options.utf8)
+		set_default_d_op(sb, &exfat_utf8_dentry_ops);
+	else {
+		sbi->nls_io = load_nls(sbi->options.iocharset);
+		if (!sbi->nls_io) {
+			exfat_err(sb, "IO charset %s not found",
+				  sbi->options.iocharset);
+			err = -EINVAL;
+			goto free_table;
+		}
+		set_default_d_op(sb, &exfat_dentry_ops);
+	}
+
+	root_inode = new_inode(sb);
+	if (!root_inode) {
+		exfat_err(sb, "failed to allocate root inode");
+		err = -ENOMEM;
+		goto free_table;
+	}
+
+	root_inode->i_ino = EXFAT_ROOT_INO;
+	inode_set_iversion(root_inode, 1);
+	err = exfat_read_root(root_inode, &root_clu);
+	if (err) {
+		exfat_err(sb, "failed to initialize root inode");
+		goto put_inode;
+	}
+
+	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
+	insert_inode_hash(root_inode);
+
+	sb->s_root = d_make_root(root_inode);
+	if (!sb->s_root) {
+		exfat_err(sb, "failed to get the root dentry");
+		err = -ENOMEM;
+		goto free_table;
+	}
+
+	return 0;
+
+put_inode:
+	iput(root_inode);
+	sb->s_root = NULL;
+
+free_table:
+	exfat_free_bitmap(sbi);
+	brelse(sbi->boot_bh);
+
+check_nls_io:
+	return err;
+}
+
+static int exfat_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, exfat_fill_super);
+}
+
+static void exfat_free_sbi(struct exfat_sb_info *sbi)
+{
+	exfat_free_iocharset(sbi);
+	kfree(sbi);
+}
+
+static void exfat_free(struct fs_context *fc)
+{
+	struct exfat_sb_info *sbi = fc->s_fs_info;
+
+	if (sbi)
+		exfat_free_sbi(sbi);
+}
+
+static int exfat_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+	struct exfat_sb_info *remount_sbi = fc->s_fs_info;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_mount_options *new_opts = &remount_sbi->options;
+	struct exfat_mount_options *cur_opts = &sbi->options;
+
+	fc->sb_flags |= SB_NODIRATIME;
+
+	sync_filesystem(sb);
+	mutex_lock(&sbi->s_lock);
+	exfat_clear_volume_dirty(sb);
+	mutex_unlock(&sbi->s_lock);
+
+	if (new_opts->allow_utime == (unsigned short)-1)
+		new_opts->allow_utime = ~new_opts->fs_dmask & 0022;
+
+	/*
+	 * Since the old settings of these mount options are cached in
+	 * inodes or dentries, they cannot be modified dynamically.
+	 */
+	if (strcmp(new_opts->iocharset, cur_opts->iocharset) ||
+	    new_opts->keep_last_dots != cur_opts->keep_last_dots ||
+	    new_opts->sys_tz != cur_opts->sys_tz ||
+	    new_opts->time_offset != cur_opts->time_offset ||
+	    !uid_eq(new_opts->fs_uid, cur_opts->fs_uid) ||
+	    !gid_eq(new_opts->fs_gid, cur_opts->fs_gid) ||
+	    new_opts->fs_fmask != cur_opts->fs_fmask ||
+	    new_opts->fs_dmask != cur_opts->fs_dmask ||
+	    new_opts->allow_utime != cur_opts->allow_utime)
+		return -EINVAL;
+
+	if (new_opts->discard != cur_opts->discard &&
+	    new_opts->discard &&
+	    !bdev_max_discard_sectors(sb->s_bdev)) {
+		exfat_warn(sb, "remounting with \"discard\" option, but the device does not support discard");
+		return -EINVAL;
+	}
+
+	swap(*cur_opts, *new_opts);
+
+	return 0;
+}
+
+static const struct fs_context_operations exfat_context_ops = {
+	.parse_param	= exfat_parse_param,
+	.get_tree	= exfat_get_tree,
+	.free		= exfat_free,
+	.reconfigure	= exfat_reconfigure,
+};
+
+static int exfat_init_fs_context(struct fs_context *fc)
+{
+	struct exfat_sb_info *sbi;
+
+	sbi = kzalloc_obj(struct exfat_sb_info);
+	if (!sbi)
+		return -ENOMEM;
+
+	mutex_init(&sbi->s_lock);
+	mutex_init(&sbi->bitmap_lock);
+	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
+			DEFAULT_RATELIMIT_BURST);
+
+	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE && fc->root) {
+		struct super_block *sb = fc->root->d_sb;
+		struct exfat_mount_options *cur_opts = &EXFAT_SB(sb)->options;
+
+		sbi->options.fs_uid = cur_opts->fs_uid;
+		sbi->options.fs_gid = cur_opts->fs_gid;
+		sbi->options.fs_fmask = cur_opts->fs_fmask;
+		sbi->options.fs_dmask = cur_opts->fs_dmask;
+	} else {
+		sbi->options.fs_uid = current_uid();
+		sbi->options.fs_gid = current_gid();
+		sbi->options.fs_fmask = current->fs->umask;
+		sbi->options.fs_dmask = current->fs->umask;
+	}
+
+	sbi->options.allow_utime = -1;
+	sbi->options.errors = EXFAT_ERRORS_RO;
+	exfat_set_iocharset(&sbi->options, exfat_default_iocharset);
+
+	fc->s_fs_info = sbi;
+	fc->ops = &exfat_context_ops;
+	return 0;
+}
+
+static void delayed_free(struct rcu_head *p)
+{
+	struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
+
+	unload_nls(sbi->nls_io);
+	exfat_free_upcase_table(sbi);
+	exfat_free_sbi(sbi);
+}
+
+static void exfat_kill_sb(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = sb->s_fs_info;
+
+	kill_block_super(sb);
+	if (sbi)
+		call_rcu(&sbi->rcu, delayed_free);
+}
+
+static struct file_system_type exfat_fs_type = {
+	.owner			= THIS_MODULE,
+	.name			= "exfat",
+	.init_fs_context	= exfat_init_fs_context,
+	.parameters		= exfat_parameters,
+	.kill_sb		= exfat_kill_sb,
+	.fs_flags		= FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
+};
+
+static void exfat_inode_init_once(void *foo)
+{
+	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
+
+	spin_lock_init(&ei->cache_lru_lock);
+	ei->nr_caches = 0;
+	ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
+	INIT_LIST_HEAD(&ei->cache_lru);
+	INIT_HLIST_NODE(&ei->i_hash_fat);
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int __init init_exfat_fs(void)
+{
+	int err;
+
+	err = exfat_cache_init();
+	if (err)
+		return err;
+
+	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
+			sizeof(struct exfat_inode_info),
+			0, SLAB_RECLAIM_ACCOUNT,
+			exfat_inode_init_once);
+	if (!exfat_inode_cachep) {
+		err = -ENOMEM;
+		goto shutdown_cache;
+	}
+
+	err = register_filesystem(&exfat_fs_type);
+	if (err)
+		goto destroy_cache;
+
+	return 0;
+
+destroy_cache:
+	kmem_cache_destroy(exfat_inode_cachep);
+shutdown_cache:
+	exfat_cache_shutdown();
+	return err;
+}
+
+static void __exit exit_exfat_fs(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(exfat_inode_cachep);
+	unregister_filesystem(&exfat_fs_type);
+	exfat_cache_shutdown();
+}
+
+module_init(init_exfat_fs);
+module_exit(exit_exfat_fs);
+
+MODULE_ALIAS_FS("exfat");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("exFAT filesystem support");
+MODULE_AUTHOR("Samsung Electronics Co., Ltd.");