1 files changed, 275 insertions, 129 deletions

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index e650e65536f8..10e872a99663 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -17,6 +17,7 @@
 #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"
@@ -30,14 +31,14 @@ static void exfat_free_iocharset(struct exfat_sb_info *sbi)
 		kfree(sbi->options.iocharset);
 }
 
-static void exfat_delayed_free(struct rcu_head *p)
+static void exfat_set_iocharset(struct exfat_mount_options *opts,
+				char *iocharset)
 {
-	struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
-
-	unload_nls(sbi->nls_io);
-	exfat_free_iocharset(sbi);
-	exfat_free_upcase_table(sbi);
-	kfree(sbi);
+	opts->iocharset = iocharset;
+	if (!strcmp(opts->iocharset, "utf8"))
+		opts->utf8 = 1;
+	else
+		opts->utf8 = 0;
 }
 
 static void exfat_put_super(struct super_block *sb)
@@ -45,30 +46,10 @@ static void exfat_put_super(struct super_block *sb)
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 
 	mutex_lock(&sbi->s_lock);
-	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state))
-		sync_blockdev(sb->s_bdev);
-	exfat_set_vol_flags(sb, VOL_CLEAN);
+	exfat_clear_volume_dirty(sb);
 	exfat_free_bitmap(sbi);
 	brelse(sbi->boot_bh);
 	mutex_unlock(&sbi->s_lock);
-
-	call_rcu(&sbi->rcu, exfat_delayed_free);
-}
-
-static int exfat_sync_fs(struct super_block *sb, int wait)
-{
-	struct exfat_sb_info *sbi = EXFAT_SB(sb);
-	int err = 0;
-
-	/* If there are some dirty buffers in the bdev inode */
-	mutex_lock(&sbi->s_lock);
-	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
-		sync_blockdev(sb->s_bdev);
-		if (exfat_set_vol_flags(sb, VOL_CLEAN))
-			err = -EIO;
-	}
-	mutex_unlock(&sbi->s_lock);
-	return err;
 }
 
 static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
@@ -77,38 +58,30 @@ static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
 
-	if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) {
-		mutex_lock(&sbi->s_lock);
-		if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
-			mutex_unlock(&sbi->s_lock);
-			return -EIO;
-		}
-		mutex_unlock(&sbi->s_lock);
-	}
-
 	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.val[0] = (unsigned int)id;
-	buf->f_fsid.val[1] = (unsigned int)(id >> 32);
+	buf->f_fsid = u64_to_fsid(id);
 	/* Unicode utf16 255 characters */
 	buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
 	return 0;
 }
 
-int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
+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;
-	bool sync;
+
+	/* retain persistent-flags */
+	new_flags |= sbi->vol_flags_persistent;
 
 	/* flags are not changed */
-	if (sbi->vol_flag == new_flag)
+	if (sbi->vol_flags == new_flags)
 		return 0;
 
-	sbi->vol_flag = new_flag;
+	sbi->vol_flags = new_flags;
 
 	/* skip updating volume dirty flag,
 	 * if this volume has been mounted with read-only
@@ -116,21 +89,30 @@ int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
 	if (sb_rdonly(sb))
 		return 0;
 
-	p_boot->vol_flags = cpu_to_le16(new_flag);
-
-	if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->boot_bh))
-		sync = true;
-	else
-		sync = false;
+	p_boot->vol_flags = cpu_to_le16(new_flags);
 
 	set_buffer_uptodate(sbi->boot_bh);
 	mark_buffer_dirty(sbi->boot_bh);
 
-	if (sync)
-		sync_dirty_buffer(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;
@@ -159,16 +141,57 @@ static int exfat_show_options(struct seq_file *m, struct dentry *root)
 		seq_puts(m, ",errors=remount-ro");
 	if (opts->discard)
 		seq_puts(m, ",discard");
-	if (opts->time_offset)
+	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 = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
+	ei = alloc_inode_sb(sb, exfat_inode_cachep, GFP_NOFS);
 	if (!ei)
 		return NULL;
 
@@ -187,9 +210,9 @@ static const struct super_operations exfat_sops = {
 	.write_inode	= exfat_write_inode,
 	.evict_inode	= exfat_evict_inode,
 	.put_super	= exfat_put_super,
-	.sync_fs	= exfat_sync_fs,
 	.statfs		= exfat_statfs,
 	.show_options	= exfat_show_options,
+	.shutdown	= exfat_shutdown,
 };
 
 enum {
@@ -202,7 +225,10 @@ enum {
 	Opt_charset,
 	Opt_errors,
 	Opt_discard,
+	Opt_keep_last_dots,
+	Opt_sys_tz,
 	Opt_time_offset,
+	Opt_zero_size_dir,
 
 	/* Deprecated options */
 	Opt_utf8,
@@ -219,16 +245,19 @@ static const struct constant_table exfat_param_enums[] = {
 };
 
 static const struct fs_parameter_spec exfat_parameters[] = {
-	fsparam_u32("uid",			Opt_uid),
-	fsparam_u32("gid",			Opt_gid),
+	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("discard",			Opt_discard),
+	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,
@@ -253,10 +282,10 @@ static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
 
 	switch (opt) {
 	case Opt_uid:
-		opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
+		opts->fs_uid = result.uid;
 		break;
 	case Opt_gid:
-		opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
+		opts->fs_gid = result.gid;
 		break;
 	case Opt_umask:
 		opts->fs_fmask = result.uint_32;
@@ -273,14 +302,20 @@ static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
 		break;
 	case Opt_charset:
 		exfat_free_iocharset(sbi);
-		opts->iocharset = param->string;
+		exfat_set_iocharset(opts, param->string);
 		param->string = NULL;
 		break;
 	case Opt_errors:
 		opts->errors = result.uint_32;
 		break;
 	case Opt_discard:
-		opts->discard = 1;
+		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:
 		/*
@@ -291,6 +326,9 @@ static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
 			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:
@@ -313,13 +351,12 @@ static void exfat_hash_init(struct super_block *sb)
 		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
 }
 
-static int exfat_read_root(struct inode *inode)
+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);
-	struct exfat_chain cdir;
-	int num_subdirs, num_clu = 0;
+	int num_subdirs;
 
 	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
 	ei->entry = -1;
@@ -327,18 +364,14 @@ static int exfat_read_root(struct inode *inode)
 	ei->flags = ALLOC_FAT_CHAIN;
 	ei->type = TYPE_DIR;
 	ei->version = 0;
-	ei->rwoffset = 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;
 
-	exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
-	if (exfat_count_num_clusters(sb, &cdir, &num_clu))
-		return -EIO;
-	i_size_write(inode, num_clu << sbi->cluster_size_bits);
+	i_size_write(inode, EXFAT_CLU_TO_B(root_clu->size, sbi));
 
-	num_subdirs = exfat_count_dir_entries(sb, &cdir);
+	num_subdirs = exfat_count_dir_entries(sb, root_clu);
 	if (num_subdirs < 0)
 		return -EIO;
 	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
@@ -347,21 +380,16 @@ static int exfat_read_root(struct inode *inode)
 	inode->i_gid = sbi->options.fs_gid;
 	inode_inc_iversion(inode);
 	inode->i_generation = 0;
-	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
+	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 = ((i_size_read(inode) + (sbi->cluster_size - 1))
-			& ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
-	EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
-	EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
-	EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
-
-	exfat_save_attr(inode, ATTR_SUBDIR);
-	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
-		current_time(inode);
-	exfat_truncate_atime(&inode->i_atime);
-	exfat_cache_init_inode(inode);
+	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;
 }
 
@@ -369,8 +397,7 @@ 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) ||
-	    logical_sect < 512 || logical_sect > 4096) {
+	if (!is_power_of_2(logical_sect)) {
 		exfat_err(sb, "bogus logical sector size %u", logical_sect);
 		return -EIO;
 	}
@@ -406,7 +433,10 @@ static int exfat_read_boot_sector(struct super_block *sb)
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 
 	/* set block size to read super block */
-	sb_min_blocksize(sb, 512);
+	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);
@@ -439,6 +469,25 @@ static int exfat_read_boot_sector(struct super_block *sb)
 		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 +
@@ -459,24 +508,27 @@ static int exfat_read_boot_sector(struct super_block *sb)
 	sbi->dentries_per_clu = 1 <<
 		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
 
-	sbi->vol_flag = le16_to_cpu(p_boot->vol_flags);
+	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;
-	sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
 
 	/* check consistencies */
-	if (sbi->num_FAT_sectors << p_boot->sect_size_bits <
-	    sbi->num_clusters * 4) {
+	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 <
-	    sbi->FAT1_start_sector + sbi->num_FAT_sectors * p_boot->num_fats) {
+	    (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_flag & VOL_DIRTY)
+
+	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_flag & ERR_MEDIUM)
+	if (sbi->vol_flags & MEDIA_FAILURE)
 		exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
 
 	/* exFAT file size is limited by a disk volume size */
@@ -535,7 +587,8 @@ static int exfat_verify_boot_region(struct super_block *sb)
 }
 
 /* mount the file system volume */
-static int __exfat_fill_super(struct super_block *sb)
+static int __exfat_fill_super(struct super_block *sb,
+		struct exfat_chain *root_clu)
 {
 	int ret;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
@@ -552,6 +605,18 @@ static int __exfat_fill_super(struct super_block *sb)
 		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");
@@ -561,7 +626,18 @@ static int __exfat_fill_super(struct super_block *sb)
 	ret = exfat_load_bitmap(sb);
 	if (ret) {
 		exfat_err(sb, "failed to load alloc-bitmap");
-		goto free_upcase_table;
+		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);
@@ -574,8 +650,6 @@ static int __exfat_fill_super(struct super_block *sb)
 
 free_alloc_bitmap:
 	exfat_free_bitmap(sbi);
-free_upcase_table:
-	exfat_free_upcase_table(sbi);
 free_bh:
 	brelse(sbi->boot_bh);
 	return ret;
@@ -586,18 +660,15 @@ 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) {
-		struct request_queue *q = bdev_get_queue(sb->s_bdev);
-
-		if (!blk_queue_discard(q)) {
-			exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
-			opts->discard = 0;
-		}
+	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;
@@ -608,7 +679,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
 	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
 
-	err = __exfat_fill_super(sb);
+	err = __exfat_fill_super(sb, &root_clu);
 	if (err) {
 		exfat_err(sb, "failed to recognize exfat type");
 		goto check_nls_io;
@@ -617,8 +688,8 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 	/* set up enough so that it can read an inode */
 	exfat_hash_init(sb);
 
-	if (!strcmp(sbi->options.iocharset, "utf8"))
-		opts->utf8 = 1;
+	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) {
@@ -627,13 +698,9 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 			err = -EINVAL;
 			goto free_table;
 		}
+		set_default_d_op(sb, &exfat_dentry_ops);
 	}
 
-	if (sbi->options.utf8)
-		sb->s_d_op = &exfat_utf8_dentry_ops;
-	else
-		sb->s_d_op = &exfat_dentry_ops;
-
 	root_inode = new_inode(sb);
 	if (!root_inode) {
 		exfat_err(sb, "failed to allocate root inode");
@@ -643,7 +710,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 
 	root_inode->i_ino = EXFAT_ROOT_INO;
 	inode_set_iversion(root_inode, 1);
-	err = exfat_read_root(root_inode);
+	err = exfat_read_root(root_inode, &root_clu);
 	if (err) {
 		exfat_err(sb, "failed to initialize root inode");
 		goto put_inode;
@@ -656,7 +723,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (!sb->s_root) {
 		exfat_err(sb, "failed to get the root dentry");
 		err = -ENOMEM;
-		goto put_inode;
+		goto free_table;
 	}
 
 	return 0;
@@ -666,15 +733,10 @@ put_inode:
 	sb->s_root = NULL;
 
 free_table:
-	exfat_free_upcase_table(sbi);
 	exfat_free_bitmap(sbi);
 	brelse(sbi->boot_bh);
 
 check_nls_io:
-	unload_nls(sbi->nls_io);
-	exfat_free_iocharset(sbi);
-	sb->s_fs_info = NULL;
-	kfree(sbi);
 	return err;
 }
 
@@ -683,20 +745,70 @@ 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_iocharset(sbi);
-		kfree(sbi);
+	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)
@@ -708,35 +820,69 @@ static int exfat_init_fs_context(struct fs_context *fc)
 		return -ENOMEM;
 
 	mutex_init(&sbi->s_lock);
+	mutex_init(&sbi->bitmap_lock);
 	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
 			DEFAULT_RATELIMIT_BURST);
 
-	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;
+	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.iocharset = exfat_default_iocharset;
 	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		= kill_block_super,
-	.fs_flags		= FS_REQUIRES_DEV,
+	.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);
 }
@@ -751,7 +897,7 @@ static int __init init_exfat_fs(void)
 
 	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
 			sizeof(struct exfat_inode_info),
-			0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+			0, SLAB_RECLAIM_ACCOUNT,
 			exfat_inode_init_once);
 	if (!exfat_inode_cachep) {
 		err = -ENOMEM;