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OpenCloudOS-Kernel/fs/fat/inode.c

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// 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/parser.h>
#include <linux/uio.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <asm/unaligned.h>
#include <linux/random.h>
#include <linux/iversion.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_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, fat_get_block, wbc);
}
static int fat_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
return mpage_writepages(mapping, wbc, fat_get_block);
}
static int fat_readpage(struct file *file, struct page *page)
{
return mpage_readpage(page, 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(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
int err;
*pagep = NULL;
err = cont_write_begin(file, mapping, pos, len, flags,
pagep, 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(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *pagep, void *fsdata)
{
struct inode *inode = mapping->host;
int err;
err = generic_write_end(file, mapping, pos, len, copied, pagep, 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, S_CTIME|S_MTIME);
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,
.readpage = fat_readpage,
.readahead = fat_readahead,
.writepage = fat_writepage,
.writepages = fat_writepages,
.write_begin = fat_write_begin,
.write_end = fat_write_end,
.direct_IO = fat_direct_IO,
.bmap = _fat_bmap
};
/*
* 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);
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 = prandom_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, &inode->i_mtime, de->time, de->date, 0);
if (sbi->options.isvfat) {
fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
de->cdate, de->ctime_cs);
fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
} else
fat_truncate_time(inode, &inode->i_mtime, S_ATIME|S_CTIME);
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, int wait);
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 = __fat_write_inode(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
fat_free_eofblocks(inode);
invalidate_inode_buffers(inode);
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;
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_MEM_SPREAD|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);
}
static int fat_remount(struct super_block *sb, int *flags, char *data)
{
bool new_rdonly;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
*flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
sync_filesystem(sb);
/* make sure we update state on remount. */
new_rdonly = *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;
}
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, int wait)
{
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;
loff_t i_pos;
sector_t blocknr;
int err, offset;
if (inode->i_ino == MSDOS_ROOT_INO)
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);
fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
&raw_entry->date, NULL);
if (sbi->options.isvfat) {
__le16 atime;
fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
&raw_entry->cdate, &raw_entry->ctime_cs);
fat_time_unix2fat(sbi, &inode->i_atime, &atime,
&raw_entry->adate, NULL);
}
spin_unlock(&sbi->inode_hash_lock);
mark_buffer_dirty(bh);
err = 0;
if (wait)
err = sync_dirty_buffer(bh);
brelse(bh);
return err;
}
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, wbc->sync_mode == WB_SYNC_ALL);
return err;
}
int fat_sync_inode(struct inode *inode)
{
return __fat_write_inode(inode, 1);
}
EXPORT_SYMBOL_GPL(fat_sync_inode);
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,
.evict_inode = fat_evict_inode,
.put_super = fat_put_super,
.statfs = fat_statfs,
.remount_fs = fat_remount,
.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_n, Opt_check_r, Opt_check_s, 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_nodots,
Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
};
static const match_table_t fat_tokens = {
{Opt_check_r, "check=relaxed"},
{Opt_check_s, "check=strict"},
{Opt_check_n, "check=normal"},
{Opt_check_r, "check=r"},
{Opt_check_s, "check=s"},
{Opt_check_n, "check=n"},
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_umask, "umask=%o"},
{Opt_dmask, "dmask=%o"},
{Opt_fmask, "fmask=%o"},
{Opt_allow_utime, "allow_utime=%o"},
{Opt_codepage, "codepage=%u"},
{Opt_usefree, "usefree"},
{Opt_nocase, "nocase"},
{Opt_quiet, "quiet"},
{Opt_showexec, "showexec"},
{Opt_debug, "debug"},
{Opt_immutable, "sys_immutable"},
{Opt_flush, "flush"},
{Opt_tz_utc, "tz=UTC"},
{Opt_time_offset, "time_offset=%d"},
{Opt_err_cont, "errors=continue"},
{Opt_err_panic, "errors=panic"},
{Opt_err_ro, "errors=remount-ro"},
{Opt_discard, "discard"},
{Opt_nfs_stale_rw, "nfs"},
{Opt_nfs_stale_rw, "nfs=stale_rw"},
{Opt_nfs_nostale_ro, "nfs=nostale_ro"},
{Opt_dos1xfloppy, "dos1xfloppy"},
{Opt_obsolete, "conv=binary"},
{Opt_obsolete, "conv=text"},
{Opt_obsolete, "conv=auto"},
{Opt_obsolete, "conv=b"},
{Opt_obsolete, "conv=t"},
{Opt_obsolete, "conv=a"},
{Opt_obsolete, "fat=%u"},
{Opt_obsolete, "blocksize=%u"},
{Opt_obsolete, "cvf_format=%20s"},
{Opt_obsolete, "cvf_options=%100s"},
{Opt_obsolete, "posix"},
{Opt_err, NULL},
};
static const match_table_t msdos_tokens = {
{Opt_nodots, "nodots"},
{Opt_nodots, "dotsOK=no"},
{Opt_dots, "dots"},
{Opt_dots, "dotsOK=yes"},
{Opt_err, NULL}
};
static const match_table_t vfat_tokens = {
{Opt_charset, "iocharset=%s"},
{Opt_shortname_lower, "shortname=lower"},
{Opt_shortname_win95, "shortname=win95"},
{Opt_shortname_winnt, "shortname=winnt"},
{Opt_shortname_mixed, "shortname=mixed"},
{Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
{Opt_utf8_no, "utf8=no"},
{Opt_utf8_no, "utf8=false"},
{Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
{Opt_utf8_yes, "utf8=yes"},
{Opt_utf8_yes, "utf8=true"},
{Opt_utf8_yes, "utf8"},
{Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
{Opt_uni_xl_no, "uni_xlate=no"},
{Opt_uni_xl_no, "uni_xlate=false"},
{Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
{Opt_uni_xl_yes, "uni_xlate=yes"},
{Opt_uni_xl_yes, "uni_xlate=true"},
{Opt_uni_xl_yes, "uni_xlate"},
{Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
{Opt_nonumtail_no, "nonumtail=no"},
{Opt_nonumtail_no, "nonumtail=false"},
{Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
{Opt_nonumtail_yes, "nonumtail=yes"},
{Opt_nonumtail_yes, "nonumtail=true"},
{Opt_nonumtail_yes, "nonumtail"},
{Opt_rodir, "rodir"},
{Opt_err, NULL}
};
static int parse_options(struct super_block *sb, char *options, int is_vfat,
int silent, int *debug, struct fat_mount_options *opts)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
char *iocharset;
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;
*debug = 0;
opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
if (!options)
goto out;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, fat_tokens, args);
if (token == Opt_err) {
if (is_vfat)
token = match_token(p, vfat_tokens, args);
else
token = match_token(p, msdos_tokens, args);
}
switch (token) {
case Opt_check_s:
opts->name_check = 's';
break;
case Opt_check_r:
opts->name_check = 'r';
break;
case Opt_check_n:
opts->name_check = 'n';
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:
*debug = 1;
break;
case Opt_immutable:
opts->sys_immutable = 1;
break;
case Opt_uid:
if (match_int(&args[0], &option))
return -EINVAL;
opts->fs_uid = make_kuid(current_user_ns(), option);
if (!uid_valid(opts->fs_uid))
return -EINVAL;
break;
case Opt_gid:
if (match_int(&args[0], &option))
return -EINVAL;
opts->fs_gid = make_kgid(current_user_ns(), option);
if (!gid_valid(opts->fs_gid))
return -EINVAL;
break;
case Opt_umask:
if (match_octal(&args[0], &option))
return -EINVAL;
opts->fs_fmask = opts->fs_dmask = option;
break;
case Opt_dmask:
if (match_octal(&args[0], &option))
return -EINVAL;
opts->fs_dmask = option;
break;
case Opt_fmask:
if (match_octal(&args[0], &option))
return -EINVAL;
opts->fs_fmask = option;
break;
case Opt_allow_utime:
if (match_octal(&args[0], &option))
return -EINVAL;
opts->allow_utime = option & (S_IWGRP | S_IWOTH);
break;
case Opt_codepage:
if (match_int(&args[0], &option))
return -EINVAL;
opts->codepage = option;
break;
case Opt_flush:
opts->flush = 1;
break;
case Opt_time_offset:
if (match_int(&args[0], &option))
return -EINVAL;
/*
* 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 (option < -24 * 60 || option > 24 * 60)
return -EINVAL;
opts->tz_set = 1;
opts->time_offset = option;
break;
case Opt_tz_utc:
opts->tz_set = 1;
opts->time_offset = 0;
break;
case Opt_err_cont:
opts->errors = FAT_ERRORS_CONT;
break;
case Opt_err_panic:
opts->errors = FAT_ERRORS_PANIC;
break;
case Opt_err_ro:
opts->errors = FAT_ERRORS_RO;
break;
case Opt_nfs_stale_rw:
opts->nfs = FAT_NFS_STALE_RW;
break;
case Opt_nfs_nostale_ro:
opts->nfs = FAT_NFS_NOSTALE_RO;
break;
case Opt_dos1xfloppy:
opts->dos1xfloppy = 1;
break;
/* msdos specific */
case Opt_dots:
opts->dotsOK = 1;
break;
case Opt_nodots:
opts->dotsOK = 0;
break;
/* vfat specific */
case Opt_charset:
fat_reset_iocharset(opts);
iocharset = match_strdup(&args[0]);
if (!iocharset)
return -ENOMEM;
opts->iocharset = iocharset;
break;
case Opt_shortname_lower:
opts->shortname = VFAT_SFN_DISPLAY_LOWER
| VFAT_SFN_CREATE_WIN95;
break;
case Opt_shortname_win95:
opts->shortname = VFAT_SFN_DISPLAY_WIN95
| VFAT_SFN_CREATE_WIN95;
break;
case Opt_shortname_winnt:
opts->shortname = VFAT_SFN_DISPLAY_WINNT
| VFAT_SFN_CREATE_WINNT;
break;
case Opt_shortname_mixed:
opts->shortname = VFAT_SFN_DISPLAY_WINNT
| VFAT_SFN_CREATE_WIN95;
break;
case Opt_utf8_no: /* 0 or no or false */
opts->utf8 = 0;
break;
case Opt_utf8_yes: /* empty or 1 or yes or true */
opts->utf8 = 1;
break;
case Opt_uni_xl_no: /* 0 or no or false */
opts->unicode_xlate = 0;
break;
case Opt_uni_xl_yes: /* empty or 1 or yes or true */
opts->unicode_xlate = 1;
break;
case Opt_nonumtail_no: /* 0 or no or false */
opts->numtail = 1; /* negated option */
break;
case Opt_nonumtail_yes: /* empty or 1 or yes or true */
opts->numtail = 0; /* negated option */
break;
case Opt_rodir:
opts->rodir = 1;
break;
case Opt_discard:
opts->discard = 1;
break;
/* obsolete mount options */
case Opt_obsolete:
fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
"not supported now", p);
break;
/* unknown option */
default:
if (!silent) {
fat_msg(sb, KERN_ERR,
"Unrecognized mount option \"%s\" "
"or missing value", p);
}
return -EINVAL;
}
}
out:
/* 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;
}
return 0;
}
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->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 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 code */
if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
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, void *data, int silent, int isvfat,
void (*setup)(struct super_block *))
{
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;
int debug;
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(sizeof(struct msdos_sb_info), GFP_KERNEL);
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);
error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
if (error)
goto out_fail;
setup(sb); /* flavour-specific stuff that needs options */
error = -EIO;
sb_min_blocksize(sb, 512);
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;
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;
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;
sprintf(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) {
struct request_queue *q = bdev_get_queue(sb->s_bdev);
if (!blk_queue_discard(q))
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:
if (fsinfo_inode)
iput(fsinfo_inode);
if (fat_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);
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_LICENSE("GPL");
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