treewide: refresh kmalloc_obj() conversionsgrafted

This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci

This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.

Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.

Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>

1 files changed, 2025 insertions, 0 deletions

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
new file mode 100644
index 000000000..f775a004c
--- /dev/null
+++ b/fs/fat/inode.c
@@ -0,0 +1,2025 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/fs/fat/inode.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *  VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
+ *  Rewritten for the constant inumbers support by Al Viro
+ *
+ *  Fixes:
+ *
+ *	Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
+ */
+
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/mpage.h>
+#include <linux/vfs.h>
+#include <linux/seq_file.h>
+#include <linux/uio.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/unaligned.h>
+#include <linux/random.h>
+#include <linux/iversion.h>
+#include <linux/fs_struct.h>
+#include "fat.h"
+
+#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
+/* if user don't select VFAT, this is undefined. */
+#define CONFIG_FAT_DEFAULT_IOCHARSET	""
+#endif
+
+#define KB_IN_SECTORS 2
+
+/* DOS dates from 1980/1/1 through 2107/12/31 */
+#define FAT_DATE_MIN (0<<9 | 1<<5 | 1)
+#define FAT_DATE_MAX (127<<9 | 12<<5 | 31)
+#define FAT_TIME_MAX (23<<11 | 59<<5 | 29)
+
+/*
+ * A deserialized copy of the on-disk structure laid out in struct
+ * fat_boot_sector.
+ */
+struct fat_bios_param_block {
+	u16	fat_sector_size;
+	u8	fat_sec_per_clus;
+	u16	fat_reserved;
+	u8	fat_fats;
+	u16	fat_dir_entries;
+	u16	fat_sectors;
+	u16	fat_fat_length;
+	u32	fat_total_sect;
+
+	u8	fat16_state;
+	u32	fat16_vol_id;
+
+	u32	fat32_length;
+	u32	fat32_root_cluster;
+	u16	fat32_info_sector;
+	u8	fat32_state;
+	u32	fat32_vol_id;
+};
+
+static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
+static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
+
+static struct fat_floppy_defaults {
+	unsigned nr_sectors;
+	unsigned sec_per_clus;
+	unsigned dir_entries;
+	unsigned media;
+	unsigned fat_length;
+} floppy_defaults[] = {
+{
+	.nr_sectors = 160 * KB_IN_SECTORS,
+	.sec_per_clus = 1,
+	.dir_entries = 64,
+	.media = 0xFE,
+	.fat_length = 1,
+},
+{
+	.nr_sectors = 180 * KB_IN_SECTORS,
+	.sec_per_clus = 1,
+	.dir_entries = 64,
+	.media = 0xFC,
+	.fat_length = 2,
+},
+{
+	.nr_sectors = 320 * KB_IN_SECTORS,
+	.sec_per_clus = 2,
+	.dir_entries = 112,
+	.media = 0xFF,
+	.fat_length = 1,
+},
+{
+	.nr_sectors = 360 * KB_IN_SECTORS,
+	.sec_per_clus = 2,
+	.dir_entries = 112,
+	.media = 0xFD,
+	.fat_length = 2,
+},
+};
+
+int fat_add_cluster(struct inode *inode)
+{
+	int err, cluster;
+
+	err = fat_alloc_clusters(inode, &cluster, 1);
+	if (err)
+		return err;
+	/* FIXME: this cluster should be added after data of this
+	 * cluster is writed */
+	err = fat_chain_add(inode, cluster, 1);
+	if (err)
+		fat_free_clusters(inode, cluster);
+	return err;
+}
+
+static inline int __fat_get_block(struct inode *inode, sector_t iblock,
+				  unsigned long *max_blocks,
+				  struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	unsigned long mapped_blocks;
+	sector_t phys, last_block;
+	int err, offset;
+
+	err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
+	if (err)
+		return err;
+	if (phys) {
+		map_bh(bh_result, sb, phys);
+		*max_blocks = min(mapped_blocks, *max_blocks);
+		return 0;
+	}
+	if (!create)
+		return 0;
+
+	if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
+		fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
+			MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
+		return -EIO;
+	}
+
+	last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
+	offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
+	/*
+	 * allocate a cluster according to the following.
+	 * 1) no more available blocks
+	 * 2) not part of fallocate region
+	 */
+	if (!offset && !(iblock < last_block)) {
+		/* TODO: multiple cluster allocation would be desirable. */
+		err = fat_add_cluster(inode);
+		if (err)
+			return err;
+	}
+	/* available blocks on this cluster */
+	mapped_blocks = sbi->sec_per_clus - offset;
+
+	*max_blocks = min(mapped_blocks, *max_blocks);
+	MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
+
+	err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
+	if (err)
+		return err;
+	if (!phys) {
+		fat_fs_error(sb,
+			     "invalid FAT chain (i_pos %lld, last_block %llu)",
+			     MSDOS_I(inode)->i_pos,
+			     (unsigned long long)last_block);
+		return -EIO;
+	}
+
+	BUG_ON(*max_blocks != mapped_blocks);
+	set_buffer_new(bh_result);
+	map_bh(bh_result, sb, phys);
+
+	return 0;
+}
+
+static int fat_get_block(struct inode *inode, sector_t iblock,
+			 struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+	int err;
+
+	err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
+	if (err)
+		return err;
+	bh_result->b_size = max_blocks << sb->s_blocksize_bits;
+	return 0;
+}
+
+static int fat_writepages(struct address_space *mapping,
+			  struct writeback_control *wbc)
+{
+	return mpage_writepages(mapping, wbc, fat_get_block);
+}
+
+static int fat_read_folio(struct file *file, struct folio *folio)
+{
+	return mpage_read_folio(folio, fat_get_block);
+}
+
+static void fat_readahead(struct readahead_control *rac)
+{
+	mpage_readahead(rac, fat_get_block);
+}
+
+static void fat_write_failed(struct address_space *mapping, loff_t to)
+{
+	struct inode *inode = mapping->host;
+
+	if (to > inode->i_size) {
+		truncate_pagecache(inode, inode->i_size);
+		fat_truncate_blocks(inode, inode->i_size);
+	}
+}
+
+static int fat_write_begin(const struct kiocb *iocb,
+			   struct address_space *mapping,
+			   loff_t pos, unsigned len,
+			   struct folio **foliop, void **fsdata)
+{
+	int err;
+
+	err = cont_write_begin(iocb, mapping, pos, len,
+				foliop, fsdata, fat_get_block,
+				&MSDOS_I(mapping->host)->mmu_private);
+	if (err < 0)
+		fat_write_failed(mapping, pos + len);
+	return err;
+}
+
+static int fat_write_end(const struct kiocb *iocb,
+			 struct address_space *mapping,
+			 loff_t pos, unsigned len, unsigned copied,
+			 struct folio *folio, void *fsdata)
+{
+	struct inode *inode = mapping->host;
+	int err;
+	err = generic_write_end(iocb, mapping, pos, len, copied, folio, fsdata);
+	if (err < len)
+		fat_write_failed(mapping, pos + len);
+	if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
+		fat_truncate_time(inode, NULL, FAT_UPDATE_CMTIME);
+		MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
+		mark_inode_dirty(inode);
+	}
+	return err;
+}
+
+static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct file *file = iocb->ki_filp;
+	struct address_space *mapping = file->f_mapping;
+	struct inode *inode = mapping->host;
+	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
+	ssize_t ret;
+
+	if (iov_iter_rw(iter) == WRITE) {
+		/*
+		 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
+		 * so we need to update the ->mmu_private to block boundary.
+		 *
+		 * But we must fill the remaining area or hole by nul for
+		 * updating ->mmu_private.
+		 *
+		 * Return 0, and fallback to normal buffered write.
+		 */
+		loff_t size = offset + count;
+		if (MSDOS_I(inode)->mmu_private < size)
+			return 0;
+	}
+
+	/*
+	 * FAT need to use the DIO_LOCKING for avoiding the race
+	 * condition of fat_get_block() and ->truncate().
+	 */
+	ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
+	if (ret < 0 && iov_iter_rw(iter) == WRITE)
+		fat_write_failed(mapping, offset + count);
+
+	return ret;
+}
+
+static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
+		struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+	int err;
+	sector_t bmap;
+	unsigned long mapped_blocks;
+
+	BUG_ON(create != 0);
+
+	err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
+	if (err)
+		return err;
+
+	if (bmap) {
+		map_bh(bh_result, sb, bmap);
+		max_blocks = min(mapped_blocks, max_blocks);
+	}
+
+	bh_result->b_size = max_blocks << sb->s_blocksize_bits;
+
+	return 0;
+}
+
+static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
+{
+	sector_t blocknr;
+
+	/* fat_get_cluster() assumes the requested blocknr isn't truncated. */
+	down_read(&MSDOS_I(mapping->host)->truncate_lock);
+	blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
+	up_read(&MSDOS_I(mapping->host)->truncate_lock);
+
+	return blocknr;
+}
+
+/*
+ * fat_block_truncate_page() zeroes out a mapping from file offset `from'
+ * up to the end of the block which corresponds to `from'.
+ * This is required during truncate to physically zeroout the tail end
+ * of that block so it doesn't yield old data if the file is later grown.
+ * Also, avoid causing failure from fsx for cases of "data past EOF"
+ */
+int fat_block_truncate_page(struct inode *inode, loff_t from)
+{
+	return block_truncate_page(inode->i_mapping, from, fat_get_block);
+}
+
+static const struct address_space_operations fat_aops = {
+	.dirty_folio	= block_dirty_folio,
+	.invalidate_folio = block_invalidate_folio,
+	.read_folio	= fat_read_folio,
+	.readahead	= fat_readahead,
+	.writepages	= fat_writepages,
+	.write_begin	= fat_write_begin,
+	.write_end	= fat_write_end,
+	.direct_IO	= fat_direct_IO,
+	.bmap		= _fat_bmap,
+	.migrate_folio	= buffer_migrate_folio,
+};
+
+/*
+ * New FAT inode stuff. We do the following:
+ *	a) i_ino is constant and has nothing with on-disk location.
+ *	b) FAT manages its own cache of directory entries.
+ *	c) *This* cache is indexed by on-disk location.
+ *	d) inode has an associated directory entry, all right, but
+ *		it may be unhashed.
+ *	e) currently entries are stored within struct inode. That should
+ *		change.
+ *	f) we deal with races in the following way:
+ *		1. readdir() and lookup() do FAT-dir-cache lookup.
+ *		2. rename() unhashes the F-d-c entry and rehashes it in
+ *			a new place.
+ *		3. unlink() and rmdir() unhash F-d-c entry.
+ *		4. fat_write_inode() checks whether the thing is unhashed.
+ *			If it is we silently return. If it isn't we do bread(),
+ *			check if the location is still valid and retry if it
+ *			isn't. Otherwise we do changes.
+ *		5. Spinlock is used to protect hash/unhash/location check/lookup
+ *		6. fat_evict_inode() unhashes the F-d-c entry.
+ *		7. lookup() and readdir() do igrab() if they find a F-d-c entry
+ *			and consider negative result as cache miss.
+ */
+
+static void fat_hash_init(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	int i;
+
+	spin_lock_init(&sbi->inode_hash_lock);
+	for (i = 0; i < FAT_HASH_SIZE; i++)
+		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
+}
+
+static inline unsigned long fat_hash(loff_t i_pos)
+{
+	return hash_32(i_pos, FAT_HASH_BITS);
+}
+
+static void dir_hash_init(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	int i;
+
+	spin_lock_init(&sbi->dir_hash_lock);
+	for (i = 0; i < FAT_HASH_SIZE; i++)
+		INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
+}
+
+void fat_attach(struct inode *inode, loff_t i_pos)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+
+	if (inode->i_ino != MSDOS_ROOT_INO) {
+		struct hlist_head *head =   sbi->inode_hashtable
+					  + fat_hash(i_pos);
+
+		spin_lock(&sbi->inode_hash_lock);
+		MSDOS_I(inode)->i_pos = i_pos;
+		hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
+		spin_unlock(&sbi->inode_hash_lock);
+	}
+
+	/* If NFS support is enabled, cache the mapping of start cluster
+	 * to directory inode. This is used during reconnection of
+	 * dentries to the filesystem root.
+	 */
+	if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
+		struct hlist_head *d_head = sbi->dir_hashtable;
+		d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
+
+		spin_lock(&sbi->dir_hash_lock);
+		hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
+		spin_unlock(&sbi->dir_hash_lock);
+	}
+}
+EXPORT_SYMBOL_GPL(fat_attach);
+
+void fat_detach(struct inode *inode)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	spin_lock(&sbi->inode_hash_lock);
+	MSDOS_I(inode)->i_pos = 0;
+	hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
+	spin_unlock(&sbi->inode_hash_lock);
+
+	if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
+		spin_lock(&sbi->dir_hash_lock);
+		hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
+		spin_unlock(&sbi->dir_hash_lock);
+	}
+}
+EXPORT_SYMBOL_GPL(fat_detach);
+
+struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
+	struct msdos_inode_info *i;
+	struct inode *inode = NULL;
+
+	spin_lock(&sbi->inode_hash_lock);
+	hlist_for_each_entry(i, head, i_fat_hash) {
+		BUG_ON(i->vfs_inode.i_sb != sb);
+		if (i->i_pos != i_pos)
+			continue;
+		inode = igrab(&i->vfs_inode);
+		if (inode)
+			break;
+	}
+	spin_unlock(&sbi->inode_hash_lock);
+	return inode;
+}
+
+static int is_exec(unsigned char *extension)
+{
+	unsigned char exe_extensions[] = "EXECOMBAT", *walk;
+
+	for (walk = exe_extensions; *walk; walk += 3)
+		if (!strncmp(extension, walk, 3))
+			return 1;
+	return 0;
+}
+
+static int fat_calc_dir_size(struct inode *inode)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	int ret, fclus, dclus;
+
+	inode->i_size = 0;
+	if (MSDOS_I(inode)->i_start == 0)
+		return 0;
+
+	ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
+	if (ret < 0)
+		return ret;
+	inode->i_size = (fclus + 1) << sbi->cluster_bits;
+
+	return 0;
+}
+
+static int fat_validate_dir(struct inode *dir)
+{
+	struct super_block *sb = dir->i_sb;
+
+	if (dir->i_nlink < 2) {
+		/* Directory should have "."/".." entries at least. */
+		fat_fs_error(sb, "corrupted directory (invalid entries)");
+		return -EIO;
+	}
+	if (MSDOS_I(dir)->i_start == 0 ||
+	    MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
+		/* Directory should point valid cluster. */
+		fat_fs_error(sb, "corrupted directory (invalid i_start)");
+		return -EIO;
+	}
+	return 0;
+}
+
+/* doesn't deal with root inode */
+int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	struct timespec64 mtime;
+	int error;
+
+	MSDOS_I(inode)->i_pos = 0;
+	inode->i_uid = sbi->options.fs_uid;
+	inode->i_gid = sbi->options.fs_gid;
+	inode_inc_iversion(inode);
+	inode->i_generation = get_random_u32();
+
+	if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
+		inode->i_generation &= ~1;
+		inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
+		inode->i_op = sbi->dir_ops;
+		inode->i_fop = &fat_dir_operations;
+
+		MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
+		MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
+		error = fat_calc_dir_size(inode);
+		if (error < 0)
+			return error;
+		MSDOS_I(inode)->mmu_private = inode->i_size;
+
+		set_nlink(inode, fat_subdirs(inode));
+
+		error = fat_validate_dir(inode);
+		if (error < 0)
+			return error;
+	} else { /* not a directory */
+		inode->i_generation |= 1;
+		inode->i_mode = fat_make_mode(sbi, de->attr,
+			((sbi->options.showexec && !is_exec(de->name + 8))
+			 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
+		MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
+
+		MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
+		inode->i_size = le32_to_cpu(de->size);
+		inode->i_op = &fat_file_inode_operations;
+		inode->i_fop = &fat_file_operations;
+		inode->i_mapping->a_ops = &fat_aops;
+		MSDOS_I(inode)->mmu_private = inode->i_size;
+	}
+	if (de->attr & ATTR_SYS) {
+		if (sbi->options.sys_immutable)
+			inode->i_flags |= S_IMMUTABLE;
+	}
+	fat_save_attrs(inode, de->attr);
+
+	inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
+			   & ~((loff_t)sbi->cluster_size - 1)) >> 9;
+
+	fat_time_fat2unix(sbi, &mtime, de->time, de->date, 0);
+	inode_set_mtime_to_ts(inode, mtime);
+	inode_set_ctime_to_ts(inode, mtime);
+	if (sbi->options.isvfat) {
+		struct timespec64 atime;
+
+		fat_time_fat2unix(sbi, &atime, 0, de->adate, 0);
+		inode_set_atime_to_ts(inode, atime);
+		fat_time_fat2unix(sbi, &MSDOS_I(inode)->i_crtime, de->ctime,
+				  de->cdate, de->ctime_cs);
+	} else
+		inode_set_atime_to_ts(inode, fat_truncate_atime(sbi, &mtime));
+
+	return 0;
+}
+
+static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
+{
+	if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
+		mutex_lock(&sbi->nfs_build_inode_lock);
+}
+
+static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
+{
+	if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
+		mutex_unlock(&sbi->nfs_build_inode_lock);
+}
+
+struct inode *fat_build_inode(struct super_block *sb,
+			struct msdos_dir_entry *de, loff_t i_pos)
+{
+	struct inode *inode;
+	int err;
+
+	fat_lock_build_inode(MSDOS_SB(sb));
+	inode = fat_iget(sb, i_pos);
+	if (inode)
+		goto out;
+	inode = new_inode(sb);
+	if (!inode) {
+		inode = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+	inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
+	inode_set_iversion(inode, 1);
+	err = fat_fill_inode(inode, de);
+	if (err) {
+		iput(inode);
+		inode = ERR_PTR(err);
+		goto out;
+	}
+	fat_attach(inode, i_pos);
+	insert_inode_hash(inode);
+out:
+	fat_unlock_build_inode(MSDOS_SB(sb));
+	return inode;
+}
+
+EXPORT_SYMBOL_GPL(fat_build_inode);
+
+static int __fat_write_inode(struct inode *inode);
+
+static int fat_sync_inode_metadata(struct inode *inode,
+				   struct writeback_control *wbc)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	struct buffer_head *bh;
+	loff_t i_pos;
+	sector_t blocknr;
+	int offset;
+
+	/* The root directory has no directory entry of its own. */
+	if (inode->i_ino == MSDOS_ROOT_INO)
+		goto sync_bhs;
+	i_pos = fat_i_pos_read(sbi, inode);
+	if (!i_pos)
+		goto sync_bhs;
+
+	fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
+	bh = sb_find_get_block_nonatomic(inode->i_sb, blocknr);
+	/*
+	 * Buffer present? We leave buffer_dirty check for sync_dirty_buffer()
+	 * for proper synchronization with ongoing IO.
+	 */
+	if (bh && buffer_uptodate(bh)) {
+		sync_dirty_buffer(bh);
+		if (buffer_write_io_error(bh)) {
+			brelse(bh);
+			return -EIO;
+		}
+	}
+	brelse(bh);
+sync_bhs:
+	return mmb_sync(&MSDOS_I(inode)->i_metadata_bhs);
+}
+
+static void fat_free_eofblocks(struct inode *inode)
+{
+	/* Release unwritten fallocated blocks on inode eviction. */
+	if ((inode->i_blocks << 9) >
+			round_up(MSDOS_I(inode)->mmu_private,
+				MSDOS_SB(inode->i_sb)->cluster_size)) {
+		int err;
+
+		fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
+		/* Fallocate results in updating the i_start/iogstart
+		 * for the zero byte file. So, make it return to
+		 * original state during evict and commit it to avoid
+		 * any corruption on the next access to the cluster
+		 * chain for the file.
+		 */
+		err = sync_inode_metadata(inode, inode_needs_sync(inode));
+		if (err) {
+			fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
+					"update on disk inode for unused "
+					"fallocated blocks, inode could be "
+					"corrupted. Please run fsck");
+		}
+
+	}
+}
+
+static void fat_evict_inode(struct inode *inode)
+{
+	truncate_inode_pages_final(&inode->i_data);
+	if (!inode->i_nlink) {
+		inode->i_size = 0;
+		fat_truncate_blocks(inode, 0);
+	} else {
+		mmb_sync(&MSDOS_I(inode)->i_metadata_bhs);
+		fat_free_eofblocks(inode);
+	}
+
+	mmb_invalidate(&MSDOS_I(inode)->i_metadata_bhs);
+	clear_inode(inode);
+	fat_cache_inval_inode(inode);
+	fat_detach(inode);
+}
+
+static void fat_set_state(struct super_block *sb,
+			unsigned int set, unsigned int force)
+{
+	struct buffer_head *bh;
+	struct fat_boot_sector *b;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+	/* do not change any thing if mounted read only */
+	if (sb_rdonly(sb) && !force)
+		return;
+
+	/* do not change state if fs was dirty */
+	if (sbi->dirty) {
+		/* warn only on set (mount). */
+		if (set)
+			fat_msg(sb, KERN_WARNING, "Volume was not properly "
+				"unmounted. Some data may be corrupt. "
+				"Please run fsck.");
+		return;
+	}
+
+	bh = sb_bread(sb, 0);
+	if (bh == NULL) {
+		fat_msg(sb, KERN_ERR, "unable to read boot sector "
+			"to mark fs as dirty");
+		return;
+	}
+
+	b = (struct fat_boot_sector *) bh->b_data;
+
+	if (is_fat32(sbi)) {
+		if (set)
+			b->fat32.state |= FAT_STATE_DIRTY;
+		else
+			b->fat32.state &= ~FAT_STATE_DIRTY;
+	} else /* fat 16 and 12 */ {
+		if (set)
+			b->fat16.state |= FAT_STATE_DIRTY;
+		else
+			b->fat16.state &= ~FAT_STATE_DIRTY;
+	}
+
+	mark_buffer_dirty(bh);
+	sync_dirty_buffer(bh);
+	brelse(bh);
+}
+
+static void fat_reset_iocharset(struct fat_mount_options *opts)
+{
+	if (opts->iocharset != fat_default_iocharset) {
+		/* Note: opts->iocharset can be NULL here */
+		kfree(opts->iocharset);
+		opts->iocharset = fat_default_iocharset;
+	}
+}
+
+static void delayed_free(struct rcu_head *p)
+{
+	struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
+	unload_nls(sbi->nls_disk);
+	unload_nls(sbi->nls_io);
+	fat_reset_iocharset(&sbi->options);
+	kfree(sbi);
+}
+
+static void fat_put_super(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+	fat_set_state(sb, 0, 0);
+
+	iput(sbi->fsinfo_inode);
+	iput(sbi->fat_inode);
+
+	call_rcu(&sbi->rcu, delayed_free);
+}
+
+static struct kmem_cache *fat_inode_cachep;
+
+static struct inode *fat_alloc_inode(struct super_block *sb)
+{
+	struct msdos_inode_info *ei;
+	ei = alloc_inode_sb(sb, fat_inode_cachep, GFP_NOFS);
+	if (!ei)
+		return NULL;
+
+	init_rwsem(&ei->truncate_lock);
+	/* Zeroing to allow iput() even if partial initialized inode. */
+	ei->mmu_private = 0;
+	ei->i_start = 0;
+	ei->i_logstart = 0;
+	ei->i_attrs = 0;
+	ei->i_pos = 0;
+	ei->i_crtime.tv_sec = 0;
+	ei->i_crtime.tv_nsec = 0;
+	mmb_init(&ei->i_metadata_bhs, &ei->vfs_inode.i_data);
+
+	return &ei->vfs_inode;
+}
+
+static void fat_free_inode(struct inode *inode)
+{
+	kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
+}
+
+static void init_once(void *foo)
+{
+	struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
+
+	spin_lock_init(&ei->cache_lru_lock);
+	ei->nr_caches = 0;
+	ei->cache_valid_id = FAT_CACHE_VALID + 1;
+	INIT_LIST_HEAD(&ei->cache_lru);
+	INIT_HLIST_NODE(&ei->i_fat_hash);
+	INIT_HLIST_NODE(&ei->i_dir_hash);
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int __init fat_init_inodecache(void)
+{
+	fat_inode_cachep = kmem_cache_create("fat_inode_cache",
+					     sizeof(struct msdos_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_ACCOUNT),
+					     init_once);
+	if (fat_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void __exit fat_destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(fat_inode_cachep);
+}
+
+int fat_reconfigure(struct fs_context *fc)
+{
+	bool new_rdonly;
+	struct super_block *sb = fc->root->d_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	fc->sb_flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
+
+	sync_filesystem(sb);
+
+	/* make sure we update state on remount. */
+	new_rdonly = fc->sb_flags & SB_RDONLY;
+	if (new_rdonly != sb_rdonly(sb)) {
+		if (new_rdonly)
+			fat_set_state(sb, 0, 0);
+		else
+			fat_set_state(sb, 1, 1);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fat_reconfigure);
+
+static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	/* If the count of free cluster is still unknown, counts it here. */
+	if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
+		int err = fat_count_free_clusters(dentry->d_sb);
+		if (err)
+			return err;
+	}
+
+	buf->f_type = dentry->d_sb->s_magic;
+	buf->f_bsize = sbi->cluster_size;
+	buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
+	buf->f_bfree = sbi->free_clusters;
+	buf->f_bavail = sbi->free_clusters;
+	buf->f_fsid = u64_to_fsid(id);
+	buf->f_namelen =
+		(sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
+
+	return 0;
+}
+
+static int __fat_write_inode(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct buffer_head *bh;
+	struct msdos_dir_entry *raw_entry;
+	struct timespec64 mtime;
+	loff_t i_pos;
+	sector_t blocknr;
+	int offset;
+
+	if (inode->i_ino == MSDOS_ROOT_INO) {
+		/* No entry to update but the metadata bh list may need syncing. */
+		set_inode_metadata_writeback(inode);
+		return 0;
+	}
+
+retry:
+	i_pos = fat_i_pos_read(sbi, inode);
+	if (!i_pos)
+		return 0;
+
+	fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
+	bh = sb_bread(sb, blocknr);
+	if (!bh) {
+		fat_msg(sb, KERN_ERR, "unable to read inode block "
+		       "for updating (i_pos %lld)", i_pos);
+		return -EIO;
+	}
+	spin_lock(&sbi->inode_hash_lock);
+	if (i_pos != MSDOS_I(inode)->i_pos) {
+		spin_unlock(&sbi->inode_hash_lock);
+		brelse(bh);
+		goto retry;
+	}
+
+	raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
+	if (S_ISDIR(inode->i_mode))
+		raw_entry->size = 0;
+	else
+		raw_entry->size = cpu_to_le32(inode->i_size);
+	raw_entry->attr = fat_make_attrs(inode);
+	fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
+	mtime = inode_get_mtime(inode);
+	fat_time_unix2fat(sbi, &mtime, &raw_entry->time,
+			  &raw_entry->date, NULL);
+	if (sbi->options.isvfat) {
+		struct timespec64 ts = inode_get_atime(inode);
+		__le16 atime;
+
+		fat_time_unix2fat(sbi, &ts, &atime, &raw_entry->adate, NULL);
+		fat_time_unix2fat(sbi, &MSDOS_I(inode)->i_crtime, &raw_entry->ctime,
+				  &raw_entry->cdate, &raw_entry->ctime_cs);
+	}
+	spin_unlock(&sbi->inode_hash_lock);
+	mark_buffer_dirty(bh);
+	brelse(bh);
+	set_inode_metadata_writeback(inode);
+	return 0;
+}
+
+static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	int err;
+
+	if (inode->i_ino == MSDOS_FSINFO_INO) {
+		struct super_block *sb = inode->i_sb;
+
+		mutex_lock(&MSDOS_SB(sb)->s_lock);
+		err = fat_clusters_flush(sb);
+		mutex_unlock(&MSDOS_SB(sb)->s_lock);
+	} else
+		err = __fat_write_inode(inode);
+
+	return err;
+}
+
+static int fat_show_options(struct seq_file *m, struct dentry *root);
+static const struct super_operations fat_sops = {
+	.alloc_inode	= fat_alloc_inode,
+	.free_inode	= fat_free_inode,
+	.write_inode	= fat_write_inode,
+	.sync_inode_metadata = fat_sync_inode_metadata,
+	.evict_inode	= fat_evict_inode,
+	.put_super	= fat_put_super,
+	.statfs		= fat_statfs,
+	.show_options	= fat_show_options,
+};
+
+static int fat_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
+	struct fat_mount_options *opts = &sbi->options;
+	int isvfat = opts->isvfat;
+
+	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", opts->fs_fmask);
+	seq_printf(m, ",dmask=%04o", opts->fs_dmask);
+	if (opts->allow_utime)
+		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
+	if (sbi->nls_disk)
+		/* strip "cp" prefix from displayed option */
+		seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
+	if (isvfat) {
+		if (sbi->nls_io)
+			seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
+
+		switch (opts->shortname) {
+		case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
+			seq_puts(m, ",shortname=win95");
+			break;
+		case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
+			seq_puts(m, ",shortname=winnt");
+			break;
+		case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
+			seq_puts(m, ",shortname=mixed");
+			break;
+		case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
+			seq_puts(m, ",shortname=lower");
+			break;
+		default:
+			seq_puts(m, ",shortname=unknown");
+			break;
+		}
+	}
+	if (opts->name_check != 'n')
+		seq_printf(m, ",check=%c", opts->name_check);
+	if (opts->usefree)
+		seq_puts(m, ",usefree");
+	if (opts->quiet)
+		seq_puts(m, ",quiet");
+	if (opts->showexec)
+		seq_puts(m, ",showexec");
+	if (opts->sys_immutable)
+		seq_puts(m, ",sys_immutable");
+	if (!isvfat) {
+		if (opts->dotsOK)
+			seq_puts(m, ",dotsOK=yes");
+		if (opts->nocase)
+			seq_puts(m, ",nocase");
+	} else {
+		if (opts->utf8)
+			seq_puts(m, ",utf8");
+		if (opts->unicode_xlate)
+			seq_puts(m, ",uni_xlate");
+		if (!opts->numtail)
+			seq_puts(m, ",nonumtail");
+		if (opts->rodir)
+			seq_puts(m, ",rodir");
+	}
+	if (opts->flush)
+		seq_puts(m, ",flush");
+	if (opts->tz_set) {
+		if (opts->time_offset)
+			seq_printf(m, ",time_offset=%d", opts->time_offset);
+		else
+			seq_puts(m, ",tz=UTC");
+	}
+	if (opts->errors == FAT_ERRORS_CONT)
+		seq_puts(m, ",errors=continue");
+	else if (opts->errors == FAT_ERRORS_PANIC)
+		seq_puts(m, ",errors=panic");
+	else
+		seq_puts(m, ",errors=remount-ro");
+	if (opts->nfs == FAT_NFS_NOSTALE_RO)
+		seq_puts(m, ",nfs=nostale_ro");
+	else if (opts->nfs)
+		seq_puts(m, ",nfs=stale_rw");
+	if (opts->discard)
+		seq_puts(m, ",discard");
+	if (opts->dos1xfloppy)
+		seq_puts(m, ",dos1xfloppy");
+
+	return 0;
+}
+
+enum {
+	Opt_check, Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask,
+	Opt_allow_utime, Opt_codepage, Opt_usefree, Opt_nocase, Opt_quiet,
+	Opt_showexec, Opt_debug, Opt_immutable, Opt_dots, Opt_dotsOK,
+	Opt_charset, Opt_shortname, Opt_utf8, Opt_utf8_bool,
+	Opt_uni_xl, Opt_uni_xl_bool, Opt_nonumtail, Opt_nonumtail_bool,
+	Opt_obsolete, Opt_flush, Opt_tz, Opt_rodir, Opt_errors, Opt_discard,
+	Opt_nfs, Opt_nfs_enum, Opt_time_offset, Opt_dos1xfloppy,
+};
+
+static const struct constant_table fat_param_check[] = {
+	{"relaxed",	'r'},
+	{"r",		'r'},
+	{"strict",	's'},
+	{"s",		's'},
+	{"normal",	'n'},
+	{"n",		'n'},
+	{}
+};
+
+static const struct constant_table fat_param_tz[] = {
+	{"UTC",		0},
+	{}
+};
+
+static const struct constant_table fat_param_errors[] = {
+	{"continue",	FAT_ERRORS_CONT},
+	{"panic",	FAT_ERRORS_PANIC},
+	{"remount-ro",	FAT_ERRORS_RO},
+	{}
+};
+
+
+static const struct constant_table fat_param_nfs[] = {
+	{"stale_rw",	FAT_NFS_STALE_RW},
+	{"nostale_ro",	FAT_NFS_NOSTALE_RO},
+	{}
+};
+
+/*
+ * These are all obsolete but we still reject invalid options.
+ * The corresponding values are therefore meaningless.
+ */
+static const struct constant_table fat_param_conv[] = {
+	{"binary",	0},
+	{"text",	0},
+	{"auto",	0},
+	{"b",		0},
+	{"t",		0},
+	{"a",		0},
+	{}
+};
+
+/* Core options. See below for vfat and msdos extras */
+const struct fs_parameter_spec fat_param_spec[] = {
+	fsparam_enum	("check",	Opt_check, fat_param_check),
+	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_u32	("codepage",	Opt_codepage),
+	fsparam_flag	("usefree",	Opt_usefree),
+	fsparam_flag	("nocase",	Opt_nocase),
+	fsparam_flag	("quiet",	Opt_quiet),
+	fsparam_flag	("showexec",	Opt_showexec),
+	fsparam_flag	("debug",	Opt_debug),
+	fsparam_flag	("sys_immutable", Opt_immutable),
+	fsparam_flag	("flush",	Opt_flush),
+	fsparam_enum	("tz",		Opt_tz, fat_param_tz),
+	fsparam_s32	("time_offset",	Opt_time_offset),
+	fsparam_enum	("errors",	Opt_errors, fat_param_errors),
+	fsparam_flag	("discard",	Opt_discard),
+	fsparam_flag	("nfs",		Opt_nfs),
+	fsparam_enum	("nfs",		Opt_nfs_enum, fat_param_nfs),
+	fsparam_flag	("dos1xfloppy",	Opt_dos1xfloppy),
+	__fsparam(fs_param_is_enum,	"conv",
+		  Opt_obsolete, fs_param_deprecated, fat_param_conv),
+	__fsparam(fs_param_is_u32,	"fat",
+		  Opt_obsolete, fs_param_deprecated, NULL),
+	__fsparam(fs_param_is_u32,	"blocksize",
+		  Opt_obsolete, fs_param_deprecated, NULL),
+	__fsparam(fs_param_is_string,	"cvf_format",
+		  Opt_obsolete, fs_param_deprecated, NULL),
+	__fsparam(fs_param_is_string,	"cvf_options",
+		  Opt_obsolete, fs_param_deprecated, NULL),
+	__fsparam(NULL,			"posix",
+		  Opt_obsolete, fs_param_deprecated, NULL),
+	{}
+};
+EXPORT_SYMBOL_GPL(fat_param_spec);
+
+static const struct fs_parameter_spec msdos_param_spec[] = {
+	fsparam_flag_no	("dots",	Opt_dots),
+	fsparam_bool	("dotsOK",	Opt_dotsOK),
+	{}
+};
+
+static const struct constant_table fat_param_shortname[] = {
+	{"lower",	VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95},
+	{"win95",	VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95},
+	{"winnt",	VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT},
+	{"mixed",	VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95},
+	{}
+};
+
+static const struct fs_parameter_spec vfat_param_spec[] = {
+	fsparam_string	("iocharset",	Opt_charset),
+	fsparam_enum	("shortname",	Opt_shortname, fat_param_shortname),
+	fsparam_flag	("utf8",	Opt_utf8),
+	fsparam_bool	("utf8",	Opt_utf8_bool),
+	fsparam_flag	("uni_xlate",	Opt_uni_xl),
+	fsparam_bool	("uni_xlate",	Opt_uni_xl_bool),
+	fsparam_flag	("nonumtail",	Opt_nonumtail),
+	fsparam_bool	("nonumtail",	Opt_nonumtail_bool),
+	fsparam_flag	("rodir",	Opt_rodir),
+	{}
+};
+
+int fat_parse_param(struct fs_context *fc, struct fs_parameter *param,
+			   bool is_vfat)
+{
+	struct fat_mount_options *opts = fc->fs_private;
+	struct fs_parse_result result;
+	int opt;
+
+	/* remount options have traditionally been ignored */
+	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE)
+		return 0;
+
+	opt = fs_parse(fc, fat_param_spec, param, &result);
+	/* If option not found in fat_param_spec, try vfat/msdos options */
+	if (opt == -ENOPARAM) {
+		if (is_vfat)
+			opt = fs_parse(fc, vfat_param_spec, param, &result);
+		else
+			opt = fs_parse(fc, msdos_param_spec, param, &result);
+	}
+
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_check:
+		opts->name_check = result.uint_32;
+		break;
+	case Opt_usefree:
+		opts->usefree = 1;
+		break;
+	case Opt_nocase:
+		if (!is_vfat)
+			opts->nocase = 1;
+		else {
+			/* for backward compatibility */
+			opts->shortname = VFAT_SFN_DISPLAY_WIN95
+				| VFAT_SFN_CREATE_WIN95;
+		}
+		break;
+	case Opt_quiet:
+		opts->quiet = 1;
+		break;
+	case Opt_showexec:
+		opts->showexec = 1;
+		break;
+	case Opt_debug:
+		opts->debug = 1;
+		break;
+	case Opt_immutable:
+		opts->sys_immutable = 1;
+		break;
+	case Opt_uid:
+		opts->fs_uid = result.uid;
+		break;
+	case Opt_gid:
+		opts->fs_gid = result.gid;
+		break;
+	case Opt_umask:
+		opts->fs_fmask = 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 & (S_IWGRP | S_IWOTH);
+		break;
+	case Opt_codepage:
+		opts->codepage = result.uint_32;
+		break;
+	case Opt_flush:
+		opts->flush = 1;
+		break;
+	case Opt_time_offset:
+		/*
+		 * GMT+-12 zones may have DST corrections so at least
+		 * 13 hours difference is needed. 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->tz_set = 1;
+		opts->time_offset = result.int_32;
+		break;
+	case Opt_tz:
+		opts->tz_set = 1;
+		opts->time_offset = result.uint_32;
+		break;
+	case Opt_errors:
+		opts->errors = result.uint_32;
+		break;
+	case Opt_nfs:
+		opts->nfs = FAT_NFS_STALE_RW;
+		break;
+	case Opt_nfs_enum:
+		opts->nfs = result.uint_32;
+		break;
+	case Opt_dos1xfloppy:
+		opts->dos1xfloppy = 1;
+		break;
+
+	/* msdos specific */
+	case Opt_dots:	/* dots / nodots */
+		opts->dotsOK = !result.negated;
+		break;
+	case Opt_dotsOK:	/* dotsOK = yes/no */
+		opts->dotsOK = result.boolean;
+		break;
+
+	/* vfat specific */
+	case Opt_charset:
+		fat_reset_iocharset(opts);
+		opts->iocharset = param->string;
+		param->string = NULL;	/* Steal string */
+		break;
+	case Opt_shortname:
+		opts->shortname = result.uint_32;
+		break;
+	case Opt_utf8:
+		opts->utf8 = 1;
+		break;
+	case Opt_utf8_bool:
+		opts->utf8 = result.boolean;
+		break;
+	case Opt_uni_xl:
+		opts->unicode_xlate = 1;
+		break;
+	case Opt_uni_xl_bool:
+		opts->unicode_xlate = result.boolean;
+		break;
+	case Opt_nonumtail:
+		opts->numtail = 0;	/* negated option */
+		break;
+	case Opt_nonumtail_bool:
+		opts->numtail = !result.boolean; /* negated option */
+		break;
+	case Opt_rodir:
+		opts->rodir = 1;
+		break;
+	case Opt_discard:
+		opts->discard = 1;
+		break;
+
+	/* obsolete mount options */
+	case Opt_obsolete:
+		printk(KERN_INFO "FAT-fs: \"%s\" option is obsolete, "
+			"not supported now", param->key);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fat_parse_param);
+
+static int fat_read_root(struct inode *inode)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	int error;
+
+	MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
+	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 = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
+	inode->i_op = sbi->dir_ops;
+	inode->i_fop = &fat_dir_operations;
+	if (is_fat32(sbi)) {
+		MSDOS_I(inode)->i_start = sbi->root_cluster;
+		error = fat_calc_dir_size(inode);
+		if (error < 0)
+			return error;
+	} else {
+		MSDOS_I(inode)->i_start = 0;
+		inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
+	}
+	inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
+			   & ~((loff_t)sbi->cluster_size - 1)) >> 9;
+	MSDOS_I(inode)->i_logstart = 0;
+	MSDOS_I(inode)->mmu_private = inode->i_size;
+
+	fat_save_attrs(inode, ATTR_DIR);
+	inode_set_mtime_to_ts(inode,
+			      inode_set_atime_to_ts(inode, inode_set_ctime(inode, 0, 0)));
+	set_nlink(inode, fat_subdirs(inode)+2);
+
+	return 0;
+}
+
+static unsigned long calc_fat_clusters(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+	/* Divide first to avoid overflow */
+	if (!is_fat12(sbi)) {
+		unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
+		return ent_per_sec * sbi->fat_length;
+	}
+
+	return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
+}
+
+static bool fat_bpb_is_zero(struct fat_boot_sector *b)
+{
+	if (get_unaligned_le16(&b->sector_size))
+		return false;
+	if (b->sec_per_clus)
+		return false;
+	if (b->reserved)
+		return false;
+	if (b->fats)
+		return false;
+	if (get_unaligned_le16(&b->dir_entries))
+		return false;
+	if (get_unaligned_le16(&b->sectors))
+		return false;
+	if (b->media)
+		return false;
+	if (b->fat_length)
+		return false;
+	if (b->secs_track)
+		return false;
+	if (b->heads)
+		return false;
+	return true;
+}
+
+static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
+	int silent, struct fat_bios_param_block *bpb)
+{
+	int error = -EINVAL;
+
+	/* Read in BPB ... */
+	memset(bpb, 0, sizeof(*bpb));
+	bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
+	bpb->fat_sec_per_clus = b->sec_per_clus;
+	bpb->fat_reserved = le16_to_cpu(b->reserved);
+	bpb->fat_fats = b->fats;
+	bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
+	bpb->fat_sectors = get_unaligned_le16(&b->sectors);
+	bpb->fat_fat_length = le16_to_cpu(b->fat_length);
+	bpb->fat_total_sect = le32_to_cpu(b->total_sect);
+
+	bpb->fat16_state = b->fat16.state;
+	bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
+
+	bpb->fat32_length = le32_to_cpu(b->fat32.length);
+	bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
+	bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
+	bpb->fat32_state = b->fat32.state;
+	bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
+
+	/* Validate this looks like a FAT filesystem BPB */
+	if (!bpb->fat_reserved) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR,
+				"bogus number of reserved sectors");
+		goto out;
+	}
+	if (!bpb->fat_fats) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
+		goto out;
+	}
+
+	/*
+	 * Earlier we checked here that b->secs_track and b->head are nonzero,
+	 * but it turns out valid FAT filesystems can have zero there.
+	 */
+
+	if (!fat_valid_media(b->media)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
+				(unsigned)b->media);
+		goto out;
+	}
+
+	if (!is_power_of_2(bpb->fat_sector_size)
+	    || (bpb->fat_sector_size < 512)
+	    || (bpb->fat_sector_size > 4096)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
+			       (unsigned)bpb->fat_sector_size);
+		goto out;
+	}
+
+	if (!is_power_of_2(bpb->fat_sec_per_clus)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
+				(unsigned)bpb->fat_sec_per_clus);
+		goto out;
+	}
+
+	if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
+		goto out;
+	}
+
+	error = 0;
+
+out:
+	return error;
+}
+
+static int fat_read_static_bpb(struct super_block *sb,
+	struct fat_boot_sector *b, int silent,
+	struct fat_bios_param_block *bpb)
+{
+	static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
+	sector_t bd_sects = bdev_nr_sectors(sb->s_bdev);
+	struct fat_floppy_defaults *fdefaults = NULL;
+	int error = -EINVAL;
+	unsigned i;
+
+	/* 16-bit DOS 1.x reliably wrote bootstrap short-jmp or near-jmp code */
+	if ((b->ignored[0] != 0xeb || b->ignored[2] != 0x90) &&
+	    (b->ignored[0] != 0xe9)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR,
+				"%s; no bootstrapping code", notdos1x);
+		goto out;
+	}
+
+	/*
+	 * If any value in this region is non-zero, it isn't archaic
+	 * DOS.
+	 */
+	if (!fat_bpb_is_zero(b)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR,
+				"%s; DOS 2.x BPB is non-zero", notdos1x);
+		goto out;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
+		if (floppy_defaults[i].nr_sectors == bd_sects) {
+			fdefaults = &floppy_defaults[i];
+			break;
+		}
+	}
+
+	if (fdefaults == NULL) {
+		if (!silent)
+			fat_msg(sb, KERN_WARNING,
+				"This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
+				(u64)bd_sects);
+		goto out;
+	}
+
+	if (!silent)
+		fat_msg(sb, KERN_INFO,
+			"This looks like a DOS 1.x volume; assuming default BPB values");
+
+	memset(bpb, 0, sizeof(*bpb));
+	bpb->fat_sector_size = SECTOR_SIZE;
+	bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
+	bpb->fat_reserved = 1;
+	bpb->fat_fats = 2;
+	bpb->fat_dir_entries = fdefaults->dir_entries;
+	bpb->fat_sectors = fdefaults->nr_sectors;
+	bpb->fat_fat_length = fdefaults->fat_length;
+
+	error = 0;
+
+out:
+	return error;
+}
+
+/*
+ * Read the super block of an MS-DOS FS.
+ */
+int fat_fill_super(struct super_block *sb, struct fs_context *fc,
+		   void (*setup)(struct super_block *))
+{
+	struct fat_mount_options *opts = fc->fs_private;
+	int silent = fc->sb_flags & SB_SILENT;
+	struct inode *root_inode = NULL, *fat_inode = NULL;
+	struct inode *fsinfo_inode = NULL;
+	struct buffer_head *bh;
+	struct fat_bios_param_block bpb;
+	struct msdos_sb_info *sbi;
+	u16 logical_sector_size;
+	u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
+	long error;
+	char buf[50];
+	struct timespec64 ts;
+
+	/*
+	 * GFP_KERNEL is ok here, because while we do hold the
+	 * superblock lock, memory pressure can't call back into
+	 * the filesystem, since we're only just about to mount
+	 * it and have no inodes etc active!
+	 */
+	sbi = kzalloc_obj(struct msdos_sb_info);
+	if (!sbi)
+		return -ENOMEM;
+	sb->s_fs_info = sbi;
+
+	sb->s_flags |= SB_NODIRATIME;
+	sb->s_magic = MSDOS_SUPER_MAGIC;
+	sb->s_op = &fat_sops;
+	sb->s_export_op = &fat_export_ops;
+	/*
+	 * fat timestamps are complex and truncated by fat itself, so
+	 * we set 1 here to be fast
+	 */
+	sb->s_time_gran = 1;
+	mutex_init(&sbi->nfs_build_inode_lock);
+	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
+			     DEFAULT_RATELIMIT_BURST);
+
+	/* UTF-8 doesn't provide FAT semantics */
+	if (!strcmp(opts->iocharset, "utf8")) {
+		fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
+		       " for FAT filesystems, filesystem will be"
+		       " case sensitive!");
+	}
+
+	/* If user doesn't specify allow_utime, it's initialized from dmask. */
+	if (opts->allow_utime == (unsigned short)-1)
+		opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
+	if (opts->unicode_xlate)
+		opts->utf8 = 0;
+	if (opts->nfs == FAT_NFS_NOSTALE_RO) {
+		sb->s_flags |= SB_RDONLY;
+		sb->s_export_op = &fat_export_ops_nostale;
+	}
+
+	/* Apply parsed options to sbi (structure copy) */
+	sbi->options = *opts;
+	/* Transfer ownership of iocharset to sbi->options */
+	opts->iocharset = NULL;
+
+	setup(sb); /* flavour-specific stuff that needs options */
+
+	error = -EINVAL;
+	if (!sb_min_blocksize(sb, 512)) {
+		fat_msg(sb, KERN_ERR, "unable to set blocksize");
+		goto out_fail;
+	}
+	error = -EIO;
+	bh = sb_bread(sb, 0);
+	if (bh == NULL) {
+		fat_msg(sb, KERN_ERR, "unable to read boot sector");
+		goto out_fail;
+	}
+
+	error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
+		&bpb);
+	if (error == -EINVAL && sbi->options.dos1xfloppy)
+		error = fat_read_static_bpb(sb,
+			(struct fat_boot_sector *)bh->b_data, silent, &bpb);
+	brelse(bh);
+
+	if (error == -EINVAL)
+		goto out_invalid;
+	else if (error)
+		goto out_fail;
+
+	logical_sector_size = bpb.fat_sector_size;
+	sbi->sec_per_clus = bpb.fat_sec_per_clus;
+
+	error = -EIO;
+	if (logical_sector_size < sb->s_blocksize) {
+		fat_msg(sb, KERN_ERR, "logical sector size too small for device"
+		       " (logical sector size = %u)", logical_sector_size);
+		goto out_fail;
+	}
+
+	if (logical_sector_size > sb->s_blocksize) {
+		struct buffer_head *bh_resize;
+
+		if (!sb_set_blocksize(sb, logical_sector_size)) {
+			fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
+			       logical_sector_size);
+			goto out_fail;
+		}
+
+		/* Verify that the larger boot sector is fully readable */
+		bh_resize = sb_bread(sb, 0);
+		if (bh_resize == NULL) {
+			fat_msg(sb, KERN_ERR, "unable to read boot sector"
+			       " (logical sector size = %lu)",
+			       sb->s_blocksize);
+			goto out_fail;
+		}
+		brelse(bh_resize);
+	}
+
+	mutex_init(&sbi->s_lock);
+	sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
+	sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
+	sbi->fats = bpb.fat_fats;
+	sbi->fat_bits = 0;		/* Don't know yet */
+	sbi->fat_start = bpb.fat_reserved;
+	sbi->fat_length = bpb.fat_fat_length;
+	sbi->root_cluster = 0;
+	sbi->free_clusters = -1;	/* Don't know yet */
+	sbi->free_clus_valid = 0;
+	sbi->prev_free = FAT_START_ENT;
+	sb->s_maxbytes = 0xffffffff;
+	fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
+	sb->s_time_min = ts.tv_sec;
+
+	fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
+			  cpu_to_le16(FAT_DATE_MAX), 0);
+	sb->s_time_max = ts.tv_sec;
+
+	if (!sbi->fat_length && bpb.fat32_length) {
+		struct fat_boot_fsinfo *fsinfo;
+		struct buffer_head *fsinfo_bh;
+
+		/* Must be FAT32 */
+		sbi->fat_bits = 32;
+		sbi->fat_length = bpb.fat32_length;
+		sbi->root_cluster = bpb.fat32_root_cluster;
+
+		/* MC - if info_sector is 0, don't multiply by 0 */
+		sbi->fsinfo_sector = bpb.fat32_info_sector;
+		if (sbi->fsinfo_sector == 0)
+			sbi->fsinfo_sector = 1;
+
+		fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
+		if (fsinfo_bh == NULL) {
+			fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
+			       " (sector = %lu)", sbi->fsinfo_sector);
+			goto out_fail;
+		}
+
+		fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
+		if (!IS_FSINFO(fsinfo)) {
+			fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
+			       "0x%08x, 0x%08x (sector = %lu)",
+			       le32_to_cpu(fsinfo->signature1),
+			       le32_to_cpu(fsinfo->signature2),
+			       sbi->fsinfo_sector);
+		} else {
+			if (sbi->options.usefree)
+				sbi->free_clus_valid = 1;
+			sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
+			sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
+		}
+
+		brelse(fsinfo_bh);
+	}
+
+	/* interpret volume ID as a little endian 32 bit integer */
+	if (is_fat32(sbi))
+		sbi->vol_id = bpb.fat32_vol_id;
+	else /* fat 16 or 12 */
+		sbi->vol_id = bpb.fat16_vol_id;
+
+	__le32 vol_id_le = cpu_to_le32(sbi->vol_id);
+	super_set_uuid(sb, (void *) &vol_id_le, sizeof(vol_id_le));
+
+	sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
+	sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
+
+	sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
+	sbi->dir_entries = bpb.fat_dir_entries;
+	if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "bogus number of directory entries"
+			       " (%u)", sbi->dir_entries);
+		goto out_invalid;
+	}
+
+	rootdir_sectors = sbi->dir_entries
+		* sizeof(struct msdos_dir_entry) / sb->s_blocksize;
+	sbi->data_start = sbi->dir_start + rootdir_sectors;
+	total_sectors = bpb.fat_sectors;
+	if (total_sectors == 0)
+		total_sectors = bpb.fat_total_sect;
+
+	if (total_sectors < sbi->data_start) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR,
+				"data area starts beyond volume (%lu > %u)",
+				sbi->data_start, total_sectors);
+		goto out_invalid;
+	}
+
+	total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
+
+	if (!is_fat32(sbi))
+		sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
+
+	/* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
+	if (is_fat32(sbi))
+		sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
+	else /* fat 16 or 12 */
+		sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
+
+	/* check that FAT table does not overflow */
+	fat_clusters = calc_fat_clusters(sb);
+	total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
+	if (total_clusters > max_fat(sb)) {
+		if (!silent)
+			fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
+			       total_clusters);
+		goto out_invalid;
+	}
+
+	sbi->max_cluster = total_clusters + FAT_START_ENT;
+	/* check the free_clusters, it's not necessarily correct */
+	if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
+		sbi->free_clusters = -1;
+	/* check the prev_free, it's not necessarily correct */
+	sbi->prev_free %= sbi->max_cluster;
+	if (sbi->prev_free < FAT_START_ENT)
+		sbi->prev_free = FAT_START_ENT;
+
+	/* set up enough so that it can read an inode */
+	fat_hash_init(sb);
+	dir_hash_init(sb);
+	fat_ent_access_init(sb);
+
+	/*
+	 * The low byte of the first FAT entry must have the same value as
+	 * the media field of the boot sector. But in real world, too many
+	 * devices are writing wrong values. So, removed that validity check.
+	 *
+	 * The removed check compared the first FAT entry to a value dependent
+	 * on the media field like this:
+	 * == (0x0F00 | media), for FAT12
+	 * == (0XFF00 | media), for FAT16
+	 * == (0x0FFFFF | media), for FAT32
+	 */
+
+	error = -EINVAL;
+	scnprintf(buf, sizeof(buf), "cp%d", sbi->options.codepage);
+	sbi->nls_disk = load_nls(buf);
+	if (!sbi->nls_disk) {
+		fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
+		goto out_fail;
+	}
+
+	/* FIXME: utf8 is using iocharset for upper/lower conversion */
+	if (sbi->options.isvfat) {
+		sbi->nls_io = load_nls(sbi->options.iocharset);
+		if (!sbi->nls_io) {
+			fat_msg(sb, KERN_ERR, "IO charset %s not found",
+			       sbi->options.iocharset);
+			goto out_fail;
+		}
+	}
+
+	error = -ENOMEM;
+	fat_inode = new_inode(sb);
+	if (!fat_inode)
+		goto out_fail;
+	sbi->fat_inode = fat_inode;
+
+	fsinfo_inode = new_inode(sb);
+	if (!fsinfo_inode)
+		goto out_fail;
+	fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
+	sbi->fsinfo_inode = fsinfo_inode;
+	insert_inode_hash(fsinfo_inode);
+
+	root_inode = new_inode(sb);
+	if (!root_inode)
+		goto out_fail;
+	root_inode->i_ino = MSDOS_ROOT_INO;
+	inode_set_iversion(root_inode, 1);
+	error = fat_read_root(root_inode);
+	if (error < 0) {
+		iput(root_inode);
+		goto out_fail;
+	}
+	error = -ENOMEM;
+	insert_inode_hash(root_inode);
+	fat_attach(root_inode, 0);
+	sb->s_root = d_make_root(root_inode);
+	if (!sb->s_root) {
+		fat_msg(sb, KERN_ERR, "get root inode failed");
+		goto out_fail;
+	}
+
+	if (sbi->options.discard && !bdev_max_discard_sectors(sb->s_bdev))
+		fat_msg(sb, KERN_WARNING,
+			"mounting with \"discard\" option, but the device does not support discard");
+
+	fat_set_state(sb, 1, 0);
+	return 0;
+
+out_invalid:
+	error = -EINVAL;
+	if (!silent)
+		fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
+
+out_fail:
+	iput(fsinfo_inode);
+	iput(fat_inode);
+	unload_nls(sbi->nls_io);
+	unload_nls(sbi->nls_disk);
+	fat_reset_iocharset(&sbi->options);
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+	return error;
+}
+
+EXPORT_SYMBOL_GPL(fat_fill_super);
+
+/*
+ * helper function for fat_flush_inodes.  This writes both the inode
+ * and the file data blocks, waiting for in flight data blocks before
+ * the start of the call.  It does not wait for any io started
+ * during the call
+ */
+static int writeback_inode(struct inode *inode)
+{
+
+	int ret;
+
+	/* if we used wait=1, sync_inode_metadata waits for the io for the
+	* inode to finish.  So wait=0 is sent down to sync_inode_metadata
+	* and filemap_fdatawrite is used for the data blocks
+	*/
+	ret = sync_inode_metadata(inode, 0);
+	if (!ret)
+		ret = filemap_fdatawrite(inode->i_mapping);
+	return ret;
+}
+
+/*
+ * write data and metadata corresponding to i1 and i2.  The io is
+ * started but we do not wait for any of it to finish.
+ *
+ * filemap_flush is used for the block device, so if there is a dirty
+ * page for a block already in flight, we will not wait and start the
+ * io over again
+ */
+int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
+{
+	int ret = 0;
+	if (!MSDOS_SB(sb)->options.flush)
+		return 0;
+	if (i1)
+		ret = writeback_inode(i1);
+	if (!ret && i2)
+		ret = writeback_inode(i2);
+	if (!ret)
+		ret = sync_blockdev_nowait(sb->s_bdev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(fat_flush_inodes);
+
+int fat_init_fs_context(struct fs_context *fc, bool is_vfat)
+{
+	struct fat_mount_options *opts;
+
+	opts = kzalloc_obj(*opts);
+	if (!opts)
+		return -ENOMEM;
+
+	opts->isvfat = is_vfat;
+	opts->fs_uid = current_uid();
+	opts->fs_gid = current_gid();
+	opts->fs_fmask = opts->fs_dmask = current_umask();
+	opts->allow_utime = -1;
+	opts->codepage = fat_default_codepage;
+	fat_reset_iocharset(opts);
+	if (is_vfat) {
+		opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
+		opts->rodir = 0;
+	} else {
+		opts->shortname = 0;
+		opts->rodir = 1;
+	}
+	opts->name_check = 'n';
+	opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
+	opts->unicode_xlate = 0;
+	opts->numtail = 1;
+	opts->usefree = opts->nocase = 0;
+	opts->tz_set = 0;
+	opts->nfs = 0;
+	opts->errors = FAT_ERRORS_RO;
+	opts->debug = 0;
+
+	opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
+
+	fc->fs_private = opts;
+	/* fc->ops assigned by caller */
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fat_init_fs_context);
+
+void fat_free_fc(struct fs_context *fc)
+{
+	struct fat_mount_options *opts = fc->fs_private;
+
+	if (opts->iocharset != fat_default_iocharset)
+		kfree(opts->iocharset);
+	kfree(fc->fs_private);
+}
+EXPORT_SYMBOL_GPL(fat_free_fc);
+
+static int __init init_fat_fs(void)
+{
+	int err;
+
+	err = fat_cache_init();
+	if (err)
+		return err;
+
+	err = fat_init_inodecache();
+	if (err)
+		goto failed;
+
+	return 0;
+
+failed:
+	fat_cache_destroy();
+	return err;
+}
+
+static void __exit exit_fat_fs(void)
+{
+	fat_cache_destroy();
+	fat_destroy_inodecache();
+}
+
+module_init(init_fat_fs)
+module_exit(exit_fat_fs)
+
+MODULE_DESCRIPTION("Core FAT filesystem support");
+MODULE_LICENSE("GPL");