openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity
linux/fs/fat/inode.c

1467 lines
38 KiB
C
Raw Blame History

/*
* 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/init.h>
#include <linux/time.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/seq_file.h>
#include <linux/msdos_fs.h>
#include <linux/pagemap.h>
#include <linux/mpage.h>
#include <linux/buffer_head.h>
#include <linux/mount.h>
#include <linux/vfs.h>
#include <linux/parser.h>
#include <linux/uio.h>
#include <asm/unaligned.h>
#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
/* if user don't select VFAT, this is undefined. */
#define CONFIG_FAT_DEFAULT_IOCHARSET ""
#endif
static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
static 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 int __fat_get_blocks(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);
sector_t phys;
unsigned long mapped_blocks;
int err, offset;
err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
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_panic(sb, "corrupted file size (i_pos %lld, %lld)",
MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
return -EIO;
}
offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
if (!offset) {
/* 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);
if (err)
return err;
BUG_ON(!phys);
BUG_ON(*max_blocks != mapped_blocks);
set_buffer_new(bh_result);
map_bh(bh_result, sb, phys);
return 0;
}
static int fat_get_blocks(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
struct super_block *sb = inode->i_sb;
int err;
unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
err = __fat_get_blocks(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_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
unsigned long max_blocks = 1;
return __fat_get_blocks(inode, iblock, &max_blocks, bh_result, create);
}
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 int fat_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
}
static int fat_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
return cont_prepare_write(page, from, to, fat_get_block,
&MSDOS_I(page->mapping->host)->mmu_private);
}
static int fat_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
struct inode *inode = page->mapping->host;
int err = generic_commit_write(file, page, from, to);
if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
mark_inode_dirty(inode);
}
return err;
}
static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
const struct iovec *iov,
loff_t offset, unsigned long nr_segs)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
if (rw == WRITE) {
/*
* FIXME: blockdev_direct_IO() doesn't use ->prepare_write(),
* 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.
*/
loff_t size = offset + iov_length(iov, nr_segs);
if (MSDOS_I(inode)->mmu_private < size)
return -EINVAL;
}
/*
* FAT need to use the DIO_LOCKING for avoiding the race
* condition of fat_get_block() and ->truncate().
*/
return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
offset, nr_segs, fat_get_blocks, NULL);
}
static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping, block, fat_get_block);
}
static struct address_space_operations fat_aops = {
.readpage = fat_readpage,
.readpages = fat_readpages,
.writepage = fat_writepage,
.writepages = fat_writepages,
.sync_page = block_sync_page,
.prepare_write = fat_prepare_write,
.commit_write = fat_commit_write,
.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_clear_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(struct super_block *sb, loff_t i_pos)
{
unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb;
tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2);
return tmp & FAT_HASH_MASK;
}
void fat_attach(struct inode *inode, loff_t i_pos)
{
struct super_block *sb = inode->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
spin_lock(&sbi->inode_hash_lock);
MSDOS_I(inode)->i_pos = i_pos;
hlist_add_head(&MSDOS_I(inode)->i_fat_hash,
sbi->inode_hashtable + fat_hash(sb, i_pos));
spin_unlock(&sbi->inode_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);
}
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(sb, i_pos);
struct hlist_node *_p;
struct msdos_inode_info *i;
struct inode *inode = NULL;
spin_lock(&sbi->inode_hash_lock);
hlist_for_each_entry(i, _p, 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;
}
/* doesn't deal with root inode */
static 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->i_version++;
inode->i_generation = get_seconds();
if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
inode->i_generation &= ~1;
inode->i_mode = MSDOS_MKMODE(de->attr,
S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
inode->i_op = sbi->dir_ops;
inode->i_fop = &fat_dir_operations;
MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
if (sbi->fat_bits == 32)
MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
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;
inode->i_nlink = fat_subdirs(inode);
} else { /* not a directory */
inode->i_generation |= 1;
inode->i_mode = MSDOS_MKMODE(de->attr,
((sbi->options.showexec &&
!is_exec(de->ext))
? S_IRUGO|S_IWUGO : S_IRWXUGO)
& ~sbi->options.fs_fmask) | S_IFREG;
MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
if (sbi->fat_bits == 32)
MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
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;
}
MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED;
/* this is as close to the truth as we can get ... */
inode->i_blksize = sbi->cluster_size;
inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
& ~((loff_t)sbi->cluster_size - 1)) >> 9;
inode->i_mtime.tv_sec =
date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date));
inode->i_mtime.tv_nsec = 0;
if (sbi->options.isvfat) {
int secs = de->ctime_cs / 100;
int csecs = de->ctime_cs % 100;
inode->i_ctime.tv_sec =
date_dos2unix(le16_to_cpu(de->ctime),
le16_to_cpu(de->cdate)) + secs;
inode->i_ctime.tv_nsec = csecs * 10000000;
inode->i_atime.tv_sec =
date_dos2unix(le16_to_cpu(0), le16_to_cpu(de->adate));
inode->i_atime.tv_nsec = 0;
} else
inode->i_ctime = inode->i_atime = inode->i_mtime;
return 0;
}
struct inode *fat_build_inode(struct super_block *sb,
struct msdos_dir_entry *de, loff_t i_pos)
{
struct inode *inode;
int err;
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->i_version = 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:
return inode;
}
EXPORT_SYMBOL_GPL(fat_build_inode);
static void fat_delete_inode(struct inode *inode)
{
truncate_inode_pages(&inode->i_data, 0);
if (!is_bad_inode(inode)) {
inode->i_size = 0;
fat_truncate(inode);
}
clear_inode(inode);
}
static void fat_clear_inode(struct inode *inode)
{
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
if (is_bad_inode(inode))
return;
lock_kernel();
spin_lock(&sbi->inode_hash_lock);
fat_cache_inval_inode(inode);
hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
spin_unlock(&sbi->inode_hash_lock);
unlock_kernel();
}
static void fat_write_super(struct super_block *sb)
{
sb->s_dirt = 0;
if (!(sb->s_flags & MS_RDONLY))
fat_clusters_flush(sb);
}
static void fat_put_super(struct super_block *sb)
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
if (sbi->nls_disk) {
unload_nls(sbi->nls_disk);
sbi->nls_disk = NULL;
sbi->options.codepage = fat_default_codepage;
}
if (sbi->nls_io) {
unload_nls(sbi->nls_io);
sbi->nls_io = NULL;
}
if (sbi->options.iocharset != fat_default_iocharset) {
kfree(sbi->options.iocharset);
sbi->options.iocharset = fat_default_iocharset;
}
sb->s_fs_info = NULL;
kfree(sbi);
}
static kmem_cache_t *fat_inode_cachep;
static struct inode *fat_alloc_inode(struct super_block *sb)
{
struct msdos_inode_info *ei;
ei = kmem_cache_alloc(fat_inode_cachep, SLAB_KERNEL);
if (!ei)
return NULL;
return &ei->vfs_inode;
}
static void fat_destroy_inode(struct inode *inode)
{
kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
}
static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
{
struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
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);
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),
init_once, NULL);
if (fat_inode_cachep == NULL)
return -ENOMEM;
return 0;
}
static void __exit fat_destroy_inodecache(void)
{
if (kmem_cache_destroy(fat_inode_cachep))
printk(KERN_INFO "fat_inode_cache: not all structures were freed\n");
}
static int fat_remount(struct super_block *sb, int *flags, char *data)
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
*flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
return 0;
}
static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
/* If the count of free cluster is still unknown, counts it here. */
if (sbi->free_clusters == -1) {
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_namelen = sbi->options.isvfat ? 260 : 12;
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;
int err = 0;
retry:
i_pos = MSDOS_I(inode)->i_pos;
if (inode->i_ino == MSDOS_ROOT_INO || !i_pos)
return 0;
lock_kernel();
bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
if (!bh) {
printk(KERN_ERR "FAT: unable to read inode block "
"for updating (i_pos %lld)\n", i_pos);
err = -EIO;
goto out;
}
spin_lock(&sbi->inode_hash_lock);
if (i_pos != MSDOS_I(inode)->i_pos) {
spin_unlock(&sbi->inode_hash_lock);
brelse(bh);
unlock_kernel();
goto retry;
}
raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
[i_pos & (sbi->dir_per_block - 1)];
if (S_ISDIR(inode->i_mode))
raw_entry->size = 0;
else
raw_entry->size = cpu_to_le32(inode->i_size);
raw_entry->attr = fat_attr(inode);
raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
if (sbi->options.isvfat) {
__le16 atime;
fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate);
raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
inode->i_ctime.tv_nsec / 10000000;
}
spin_unlock(&sbi->inode_hash_lock);
mark_buffer_dirty(bh);
if (wait)
err = sync_dirty_buffer(bh);
brelse(bh);
out:
unlock_kernel();
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 vfsmount *mnt);
static struct super_operations fat_sops = {
.alloc_inode = fat_alloc_inode,
.destroy_inode = fat_destroy_inode,
.write_inode = fat_write_inode,
.delete_inode = fat_delete_inode,
.put_super = fat_put_super,
.write_super = fat_write_super,
.statfs = fat_statfs,
.clear_inode = fat_clear_inode,
.remount_fs = fat_remount,
.read_inode = make_bad_inode,
.show_options = fat_show_options,
};
/*
* a FAT file handle with fhtype 3 is
* 0/ i_ino - for fast, reliable lookup if still in the cache
* 1/ i_generation - to see if i_ino is still valid
* bit 0 == 0 iff directory
* 2/ i_pos(8-39) - if ino has changed, but still in cache
* 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
* 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
*
* Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
* i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
* of i_logstart is used to store the directory entry offset.
*/
static struct dentry *
fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype,
int (*acceptable)(void *context, struct dentry *de),
void *context)
{
if (fhtype != 3)
return ERR_PTR(-ESTALE);
if (len < 5)
return ERR_PTR(-ESTALE);
return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context);
}
static struct dentry *fat_get_dentry(struct super_block *sb, void *inump)
{
struct inode *inode = NULL;
struct dentry *result;
__u32 *fh = inump;
inode = iget(sb, fh[0]);
if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) {
if (inode)
iput(inode);
inode = NULL;
}
if (!inode) {
loff_t i_pos;
int i_logstart = fh[3] & 0x0fffffff;
i_pos = (loff_t)fh[2] << 8;
i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
/* try 2 - see if i_pos is in F-d-c
* require i_logstart to be the same
* Will fail if you truncate and then re-write
*/
inode = fat_iget(sb, i_pos);
if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
iput(inode);
inode = NULL;
}
}
if (!inode) {
/* For now, do nothing
* What we could do is:
* follow the file starting at fh[4], and record
* the ".." entry, and the name of the fh[2] entry.
* The follow the ".." file finding the next step up.
* This way we build a path to the root of
* the tree. If this works, we lookup the path and so
* get this inode into the cache.
* Finally try the fat_iget lookup again
* If that fails, then weare totally out of luck
* But all that is for another day
*/
}
if (!inode)
return ERR_PTR(-ESTALE);
/* now to find a dentry.
* If possible, get a well-connected one
*/
result = d_alloc_anon(inode);
if (result == NULL) {
iput(inode);
return ERR_PTR(-ENOMEM);
}
result->d_op = sb->s_root->d_op;
return result;
}
static int
fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
{
int len = *lenp;
struct inode *inode = de->d_inode;
u32 ipos_h, ipos_m, ipos_l;
if (len < 5)
return 255; /* no room */
ipos_h = MSDOS_I(inode)->i_pos >> 8;
ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
*lenp = 5;
fh[0] = inode->i_ino;
fh[1] = inode->i_generation;
fh[2] = ipos_h;
fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
spin_lock(&de->d_lock);
fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
spin_unlock(&de->d_lock);
return 3;
}
static struct dentry *fat_get_parent(struct dentry *child)
{
struct buffer_head *bh;
struct msdos_dir_entry *de;
loff_t i_pos;
struct dentry *parent;
struct inode *inode;
int err;
lock_kernel();
err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
if (err) {
parent = ERR_PTR(err);
goto out;
}
inode = fat_build_inode(child->d_sb, de, i_pos);
brelse(bh);
if (IS_ERR(inode)) {
parent = ERR_PTR(PTR_ERR(inode));
goto out;
}
parent = d_alloc_anon(inode);
if (!parent) {
iput(inode);
parent = ERR_PTR(-ENOMEM);
}
out:
unlock_kernel();
return parent;
}
static struct export_operations fat_export_ops = {
.decode_fh = fat_decode_fh,
.encode_fh = fat_encode_fh,
.get_dentry = fat_get_dentry,
.get_parent = fat_get_parent,
};
static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
{
struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
struct fat_mount_options *opts = &sbi->options;
int isvfat = opts->isvfat;
if (opts->fs_uid != 0)
seq_printf(m, ",uid=%u", opts->fs_uid);
if (opts->fs_gid != 0)
seq_printf(m, ",gid=%u", opts->fs_gid);
seq_printf(m, ",fmask=%04o", opts->fs_fmask);
seq_printf(m, ",dmask=%04o", opts->fs_dmask);
if (sbi->nls_disk)
seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
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->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");
}
return 0;
}
enum {
Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, 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_obsolate, Opt_err,
};
static 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_codepage, "codepage=%u"},
{Opt_nocase, "nocase"},
{Opt_quiet, "quiet"},
{Opt_showexec, "showexec"},
{Opt_debug, "debug"},
{Opt_immutable, "sys_immutable"},
{Opt_obsolate, "conv=binary"},
{Opt_obsolate, "conv=text"},
{Opt_obsolate, "conv=auto"},
{Opt_obsolate, "conv=b"},
{Opt_obsolate, "conv=t"},
{Opt_obsolate, "conv=a"},
{Opt_obsolate, "fat=%u"},
{Opt_obsolate, "blocksize=%u"},
{Opt_obsolate, "cvf_format=%20s"},
{Opt_obsolate, "cvf_options=%100s"},
{Opt_obsolate, "posix"},
{Opt_err, NULL}
};
static match_table_t msdos_tokens = {
{Opt_nodots, "nodots"},
{Opt_nodots, "dotsOK=no"},
{Opt_dots, "dots"},
{Opt_dots, "dotsOK=yes"},
{Opt_err, NULL}
};
static 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_err, NULL}
};
static int parse_options(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->fs->umask;
opts->codepage = fat_default_codepage;
opts->iocharset = fat_default_iocharset;
if (is_vfat)
opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
else
opts->shortname = 0;
opts->name_check = 'n';
opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
opts->utf8 = opts->unicode_xlate = 0;
opts->numtail = 1;
opts->nocase = 0;
*debug = 0;
if (!options)
return 0;
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_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 0;
opts->fs_uid = option;
break;
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
opts->fs_gid = option;
break;
case Opt_umask:
if (match_octal(&args[0], &option))
return 0;
opts->fs_fmask = opts->fs_dmask = option;
break;
case Opt_dmask:
if (match_octal(&args[0], &option))
return 0;
opts->fs_dmask = option;
break;
case Opt_fmask:
if (match_octal(&args[0], &option))
return 0;
opts->fs_fmask = option;
break;
case Opt_codepage:
if (match_int(&args[0], &option))
return 0;
opts->codepage = option;
break;
/* msdos specific */
case Opt_dots:
opts->dotsOK = 1;
break;
case Opt_nodots:
opts->dotsOK = 0;
break;
/* vfat specific */
case Opt_charset:
if (opts->iocharset != fat_default_iocharset)
kfree(opts->iocharset);
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;
/* obsolete mount options */
case Opt_obsolate:
printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
"not supported now\n", p);
break;
/* unknown option */
default:
if (!silent) {
printk(KERN_ERR
"FAT: Unrecognized mount option \"%s\" "
"or missing value\n", p);
}
return -EINVAL;
}
}
/* UTF-8 doesn't provide FAT semantics */
if (!strcmp(opts->iocharset, "utf8")) {
printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
" for FAT filesystems, filesystem will be case sensitive!\n");
}
if (opts->unicode_xlate)
opts->utf8 = 0;
return 0;
}
static int fat_read_root(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
int error;
MSDOS_I(inode)->i_pos = 0;
inode->i_uid = sbi->options.fs_uid;
inode->i_gid = sbi->options.fs_gid;
inode->i_version++;
inode->i_generation = 0;
inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
inode->i_op = sbi->dir_ops;
inode->i_fop = &fat_dir_operations;
if (sbi->fat_bits == 32) {
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_blksize = sbi->cluster_size;
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;
MSDOS_I(inode)->i_attrs = ATTR_NONE;
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;
inode->i_nlink = fat_subdirs(inode)+2;
return 0;
}
/*
* Read the super block of an MS-DOS FS.
*/
int fat_fill_super(struct super_block *sb, void *data, int silent,
struct inode_operations *fs_dir_inode_ops, int isvfat)
{
struct inode *root_inode = NULL;
struct buffer_head *bh;
struct fat_boot_sector *b;
struct msdos_sb_info *sbi;
u16 logical_sector_size;
u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
int debug;
unsigned int media;
long error;
char buf[50];
sbi = kmalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sb->s_fs_info = sbi;
memset(sbi, 0, sizeof(struct msdos_sb_info));
sb->s_flags |= MS_NODIRATIME;
sb->s_magic = MSDOS_SUPER_MAGIC;
sb->s_op = &fat_sops;
sb->s_export_op = &fat_export_ops;
sbi->dir_ops = fs_dir_inode_ops;
error = parse_options(data, isvfat, silent, &debug, &sbi->options);
if (error)
goto out_fail;
error = -EIO;
sb_min_blocksize(sb, 512);
bh = sb_bread(sb, 0);
if (bh == NULL) {
printk(KERN_ERR "FAT: unable to read boot sector\n");
goto out_fail;
}
b = (struct fat_boot_sector *) bh->b_data;
if (!b->reserved) {
if (!silent)
printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
brelse(bh);
goto out_invalid;
}
if (!b->fats) {
if (!silent)
printk(KERN_ERR "FAT: bogus number of FAT structure\n");
brelse(bh);
goto out_invalid;
}
/*
* Earlier we checked here that b->secs_track and b->head are nonzero,
* but it turns out valid FAT filesystems can have zero there.
*/
media = b->media;
if (!FAT_VALID_MEDIA(media)) {
if (!silent)
printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
media);
brelse(bh);
goto out_invalid;
}
logical_sector_size =
le16_to_cpu(get_unaligned((__le16 *)&b->sector_size));
if (!logical_sector_size
|| (logical_sector_size & (logical_sector_size - 1))
|| (logical_sector_size < 512)
|| (PAGE_CACHE_SIZE < logical_sector_size)) {
if (!silent)
printk(KERN_ERR "FAT: bogus logical sector size %u\n",
logical_sector_size);
brelse(bh);
goto out_invalid;
}
sbi->sec_per_clus = b->sec_per_clus;
if (!sbi->sec_per_clus
|| (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) {
if (!silent)
printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
sbi->sec_per_clus);
brelse(bh);
goto out_invalid;
}
if (logical_sector_size < sb->s_blocksize) {
printk(KERN_ERR "FAT: logical sector size too small for device"
" (logical sector size = %u)\n", logical_sector_size);
brelse(bh);
goto out_fail;
}
if (logical_sector_size > sb->s_blocksize) {
brelse(bh);
if (!sb_set_blocksize(sb, logical_sector_size)) {
printk(KERN_ERR "FAT: unable to set blocksize %u\n",
logical_sector_size);
goto out_fail;
}
bh = sb_bread(sb, 0);
if (bh == NULL) {
printk(KERN_ERR "FAT: unable to read boot sector"
" (logical sector size = %lu)\n",
sb->s_blocksize);
goto out_fail;
}
b = (struct fat_boot_sector *) bh->b_data;
}
sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
sbi->fats = b->fats;
sbi->fat_bits = 0; /* Don't know yet */
sbi->fat_start = le16_to_cpu(b->reserved);
sbi->fat_length = le16_to_cpu(b->fat_length);
sbi->root_cluster = 0;
sbi->free_clusters = -1; /* Don't know yet */
sbi->prev_free = FAT_START_ENT;
if (!sbi->fat_length && b->fat32_length) {
struct fat_boot_fsinfo *fsinfo;
struct buffer_head *fsinfo_bh;
/* Must be FAT32 */
sbi->fat_bits = 32;
sbi->fat_length = le32_to_cpu(b->fat32_length);
sbi->root_cluster = le32_to_cpu(b->root_cluster);
sb->s_maxbytes = 0xffffffff;
/* MC - if info_sector is 0, don't multiply by 0 */
sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
if (sbi->fsinfo_sector == 0)
sbi->fsinfo_sector = 1;
fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
if (fsinfo_bh == NULL) {
printk(KERN_ERR "FAT: bread failed, FSINFO block"
" (sector = %lu)\n", sbi->fsinfo_sector);
brelse(bh);
goto out_fail;
}
fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
if (!IS_FSINFO(fsinfo)) {
printk(KERN_WARNING
"FAT: Did not find valid FSINFO signature.\n"
" Found signature1 0x%08x signature2 0x%08x"
" (sector = %lu)\n",
le32_to_cpu(fsinfo->signature1),
le32_to_cpu(fsinfo->signature2),
sbi->fsinfo_sector);
} else {
sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
}
brelse(fsinfo_bh);
}
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 =
le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries));
if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
if (!silent)
printk(KERN_ERR "FAT: bogus directroy-entries per block"
" (%u)\n", sbi->dir_entries);
brelse(bh);
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 = le16_to_cpu(get_unaligned((__le16 *)&b->sectors));
if (total_sectors == 0)
total_sectors = le32_to_cpu(b->total_sect);
total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
if (sbi->fat_bits != 32)
sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
/* check that FAT table does not overflow */
fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
if (total_clusters > MAX_FAT(sb)) {
if (!silent)
printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
total_clusters);
brelse(bh);
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;
brelse(bh);
/* set up enough so that it can read an inode */
fat_hash_init(sb);
fat_ent_access_init(sb);
/*
* The low byte of FAT's first entry must have same value with
* media-field. But in real world, too many devices is
* writing wrong value. So, removed that validity check.
*
* if (FAT_FIRST_ENT(sb, media) != first)
*/
error = -EINVAL;
sprintf(buf, "cp%d", sbi->options.codepage);
sbi->nls_disk = load_nls(buf);
if (!sbi->nls_disk) {
printk(KERN_ERR "FAT: codepage %s not found\n", 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) {
printk(KERN_ERR "FAT: IO charset %s not found\n",
sbi->options.iocharset);
goto out_fail;
}
}
error = -ENOMEM;
root_inode = new_inode(sb);
if (!root_inode)
goto out_fail;
root_inode->i_ino = MSDOS_ROOT_INO;
root_inode->i_version = 1;
error = fat_read_root(root_inode);
if (error < 0)
goto out_fail;
error = -ENOMEM;
insert_inode_hash(root_inode);
sb->s_root = d_alloc_root(root_inode);
if (!sb->s_root) {
printk(KERN_ERR "FAT: get root inode failed\n");
goto out_fail;
}
return 0;
out_invalid:
error = -EINVAL;
if (!silent)
printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
" on dev %s.\n", sb->s_id);
out_fail:
if (root_inode)
iput(root_inode);
if (sbi->nls_io)
unload_nls(sbi->nls_io);
if (sbi->nls_disk)
unload_nls(sbi->nls_disk);
if (sbi->options.iocharset != fat_default_iocharset)
kfree(sbi->options.iocharset);
sb->s_fs_info = NULL;
kfree(sbi);
return error;
}
EXPORT_SYMBOL_GPL(fat_fill_super);
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");
Reference in New Issue View Git Blame Copy Permalink