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2a32cebd6c
linux/fs/hpfs/super.c
Al Viro 2a32cebd6c Fix races around the access to ->s_options 
Put generic_show_options read access to s_options under rcu_read_lock,
split save_mount_options() into "we are setting it the first time"
(uses in foo_fill_super()) and "we are relacing and freeing the old one",
synchronize_rcu() before kfree() in the latter.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-05-09 10:51:34 -04:00

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/*
* linux/fs/hpfs/super.c
*
* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
*
* mounting, unmounting, error handling
*/
#include "hpfs_fn.h"
#include <linux/module.h>
#include <linux/parser.h>
#include <linux/init.h>
#include <linux/statfs.h>
#include <linux/magic.h>
#include <linux/sched.h>
/* Mark the filesystem dirty, so that chkdsk checks it when os/2 booted */
static void mark_dirty(struct super_block *s)
{
if (hpfs_sb(s)->sb_chkdsk && !(s->s_flags & MS_RDONLY)) {
struct buffer_head *bh;
struct hpfs_spare_block *sb;
if ((sb = hpfs_map_sector(s, 17, &bh, 0))) {
sb->dirty = 1;
sb->old_wrote = 0;
mark_buffer_dirty(bh);
brelse(bh);
}
}
}
/* Mark the filesystem clean (mark it dirty for chkdsk if chkdsk==2 or if there
were errors) */
static void unmark_dirty(struct super_block *s)
{
struct buffer_head *bh;
struct hpfs_spare_block *sb;
if (s->s_flags & MS_RDONLY) return;
if ((sb = hpfs_map_sector(s, 17, &bh, 0))) {
sb->dirty = hpfs_sb(s)->sb_chkdsk > 1 - hpfs_sb(s)->sb_was_error;
sb->old_wrote = hpfs_sb(s)->sb_chkdsk >= 2 && !hpfs_sb(s)->sb_was_error;
mark_buffer_dirty(bh);
brelse(bh);
}
}
/* Filesystem error... */
static char err_buf[1024];
void hpfs_error(struct super_block *s, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
vsnprintf(err_buf, sizeof(err_buf), fmt, args);
va_end(args);
printk("HPFS: filesystem error: %s", err_buf);
if (!hpfs_sb(s)->sb_was_error) {
if (hpfs_sb(s)->sb_err == 2) {
printk("; crashing the system because you wanted it\n");
mark_dirty(s);
panic("HPFS panic");
} else if (hpfs_sb(s)->sb_err == 1) {
if (s->s_flags & MS_RDONLY) printk("; already mounted read-only\n");
else {
printk("; remounting read-only\n");
mark_dirty(s);
s->s_flags |= MS_RDONLY;
}
} else if (s->s_flags & MS_RDONLY) printk("; going on - but anything won't be destroyed because it's read-only\n");
else printk("; corrupted filesystem mounted read/write - your computer will explode within 20 seconds ... but you wanted it so!\n");
} else printk("\n");
hpfs_sb(s)->sb_was_error = 1;
}
/*
* A little trick to detect cycles in many hpfs structures and don't let the
* kernel crash on corrupted filesystem. When first called, set c2 to 0.
*
* BTW. chkdsk doesn't detect cycles correctly. When I had 2 lost directories
* nested each in other, chkdsk locked up happilly.
*/
int hpfs_stop_cycles(struct super_block *s, int key, int *c1, int *c2,
char *msg)
{
if (*c2 && *c1 == key) {
hpfs_error(s, "cycle detected on key %08x in %s", key, msg);
return 1;
}
(*c2)++;
if (!((*c2 - 1) & *c2)) *c1 = key;
return 0;
}
static void hpfs_put_super(struct super_block *s)
{
struct hpfs_sb_info *sbi = hpfs_sb(s);
kfree(sbi->sb_cp_table);
kfree(sbi->sb_bmp_dir);
unmark_dirty(s);
s->s_fs_info = NULL;
kfree(sbi);
}
unsigned hpfs_count_one_bitmap(struct super_block *s, secno secno)
{
struct quad_buffer_head qbh;
unsigned *bits;
unsigned i, count;
if (!(bits = hpfs_map_4sectors(s, secno, &qbh, 4))) return 0;
count = 0;
for (i = 0; i < 2048 / sizeof(unsigned); i++) {
unsigned b;
if (!bits[i]) continue;
for (b = bits[i]; b; b>>=1) count += b & 1;
}
hpfs_brelse4(&qbh);
return count;
}
static unsigned count_bitmaps(struct super_block *s)
{
unsigned n, count, n_bands;
n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
count = 0;
for (n = 0; n < n_bands; n++)
count += hpfs_count_one_bitmap(s, hpfs_sb(s)->sb_bmp_dir[n]);
return count;
}
static int hpfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *s = dentry->d_sb;
struct hpfs_sb_info *sbi = hpfs_sb(s);
u64 id = huge_encode_dev(s->s_bdev->bd_dev);
lock_kernel();
/*if (sbi->sb_n_free == -1) {*/
sbi->sb_n_free = count_bitmaps(s);
sbi->sb_n_free_dnodes = hpfs_count_one_bitmap(s, sbi->sb_dmap);
/*}*/
buf->f_type = s->s_magic;
buf->f_bsize = 512;
buf->f_blocks = sbi->sb_fs_size;
buf->f_bfree = sbi->sb_n_free;
buf->f_bavail = sbi->sb_n_free;
buf->f_files = sbi->sb_dirband_size / 4;
buf->f_ffree = sbi->sb_n_free_dnodes;
buf->f_fsid.val[0] = (u32)id;
buf->f_fsid.val[1] = (u32)(id >> 32);
buf->f_namelen = 254;
unlock_kernel();
return 0;
}
static struct kmem_cache * hpfs_inode_cachep;
static struct inode *hpfs_alloc_inode(struct super_block *sb)
{
struct hpfs_inode_info *ei;
ei = (struct hpfs_inode_info *)kmem_cache_alloc(hpfs_inode_cachep, GFP_NOFS);
if (!ei)
return NULL;
ei->vfs_inode.i_version = 1;
return &ei->vfs_inode;
}
static void hpfs_destroy_inode(struct inode *inode)
{
kmem_cache_free(hpfs_inode_cachep, hpfs_i(inode));
}
static void init_once(void *foo)
{
struct hpfs_inode_info *ei = (struct hpfs_inode_info *) foo;
mutex_init(&ei->i_mutex);
mutex_init(&ei->i_parent_mutex);
inode_init_once(&ei->vfs_inode);
}
static int init_inodecache(void)
{
hpfs_inode_cachep = kmem_cache_create("hpfs_inode_cache",
sizeof(struct hpfs_inode_info),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
init_once);
if (hpfs_inode_cachep == NULL)
return -ENOMEM;
return 0;
}
static void destroy_inodecache(void)
{
kmem_cache_destroy(hpfs_inode_cachep);
}
/*
* A tiny parser for option strings, stolen from dosfs.
* Stolen again from read-only hpfs.
* And updated for table-driven option parsing.
*/
enum {
Opt_help, Opt_uid, Opt_gid, Opt_umask, Opt_case_lower, Opt_case_asis,
Opt_conv_binary, Opt_conv_text, Opt_conv_auto,
Opt_check_none, Opt_check_normal, Opt_check_strict,
Opt_err_cont, Opt_err_ro, Opt_err_panic,
Opt_eas_no, Opt_eas_ro, Opt_eas_rw,
Opt_chkdsk_no, Opt_chkdsk_errors, Opt_chkdsk_always,
Opt_timeshift, Opt_err,
};
static const match_table_t tokens = {
{Opt_help, "help"},
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_umask, "umask=%o"},
{Opt_case_lower, "case=lower"},
{Opt_case_asis, "case=asis"},
{Opt_conv_binary, "conv=binary"},
{Opt_conv_text, "conv=text"},
{Opt_conv_auto, "conv=auto"},
{Opt_check_none, "check=none"},
{Opt_check_normal, "check=normal"},
{Opt_check_strict, "check=strict"},
{Opt_err_cont, "errors=continue"},
{Opt_err_ro, "errors=remount-ro"},
{Opt_err_panic, "errors=panic"},
{Opt_eas_no, "eas=no"},
{Opt_eas_ro, "eas=ro"},
{Opt_eas_rw, "eas=rw"},
{Opt_chkdsk_no, "chkdsk=no"},
{Opt_chkdsk_errors, "chkdsk=errors"},
{Opt_chkdsk_always, "chkdsk=always"},
{Opt_timeshift, "timeshift=%d"},
{Opt_err, NULL},
};
static int parse_opts(char *opts, uid_t *uid, gid_t *gid, umode_t *umask,
int *lowercase, int *conv, int *eas, int *chk, int *errs,
int *chkdsk, int *timeshift)
{
char *p;
int option;
if (!opts)
return 1;
/*printk("Parsing opts: '%s'\n",opts);*/
while ((p = strsep(&opts, ",")) != NULL) {
substring_t args[MAX_OPT_ARGS];
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_help:
return 2;
case Opt_uid:
if (match_int(args, &option))
return 0;
*uid = option;
break;
case Opt_gid:
if (match_int(args, &option))
return 0;
*gid = option;
break;
case Opt_umask:
if (match_octal(args, &option))
return 0;
*umask = option;
break;
case Opt_case_lower:
*lowercase = 1;
break;
case Opt_case_asis:
*lowercase = 0;
break;
case Opt_conv_binary:
*conv = CONV_BINARY;
break;
case Opt_conv_text:
*conv = CONV_TEXT;
break;
case Opt_conv_auto:
*conv = CONV_AUTO;
break;
case Opt_check_none:
*chk = 0;
break;
case Opt_check_normal:
*chk = 1;
break;
case Opt_check_strict:
*chk = 2;
break;
case Opt_err_cont:
*errs = 0;
break;
case Opt_err_ro:
*errs = 1;
break;
case Opt_err_panic:
*errs = 2;
break;
case Opt_eas_no:
*eas = 0;
break;
case Opt_eas_ro:
*eas = 1;
break;
case Opt_eas_rw:
*eas = 2;
break;
case Opt_chkdsk_no:
*chkdsk = 0;
break;
case Opt_chkdsk_errors:
*chkdsk = 1;
break;
case Opt_chkdsk_always:
*chkdsk = 2;
break;
case Opt_timeshift:
{
int m = 1;
char *rhs = args[0].from;
if (!rhs || !*rhs)
return 0;
if (*rhs == '-') m = -1;
if (*rhs == '+' || *rhs == '-') rhs++;
*timeshift = simple_strtoul(rhs, &rhs, 0) * m;
if (*rhs)
return 0;
break;
}
default:
return 0;
}
}
return 1;
}
static inline void hpfs_help(void)
{
printk("\n\
HPFS filesystem options:\n\
help do not mount and display this text\n\
uid=xxx set uid of files that don't have uid specified in eas\n\
gid=xxx set gid of files that don't have gid specified in eas\n\
umask=xxx set mode of files that don't have mode specified in eas\n\
case=lower lowercase all files\n\
case=asis do not lowercase files (default)\n\
conv=binary do not convert CR/LF -> LF (default)\n\
conv=auto convert only files with known text extensions\n\
conv=text convert all files\n\
check=none no fs checks - kernel may crash on corrupted filesystem\n\
check=normal do some checks - it should not crash (default)\n\
check=strict do extra time-consuming checks, used for debugging\n\
errors=continue continue on errors\n\
errors=remount-ro remount read-only if errors found (default)\n\
errors=panic panic on errors\n\
chkdsk=no do not mark fs for chkdsking even if there were errors\n\
chkdsk=errors mark fs dirty if errors found (default)\n\
chkdsk=always always mark fs dirty - used for debugging\n\
eas=no ignore extended attributes\n\
eas=ro read but do not write extended attributes\n\
eas=rw r/w eas => enables chmod, chown, mknod, ln -s (default)\n\
timeshift=nnn add nnn seconds to file times\n\
\n");
}
static int hpfs_remount_fs(struct super_block *s, int *flags, char *data)
{
uid_t uid;
gid_t gid;
umode_t umask;
int lowercase, conv, eas, chk, errs, chkdsk, timeshift;
int o;
struct hpfs_sb_info *sbi = hpfs_sb(s);
char *new_opts = kstrdup(data, GFP_KERNEL);
*flags |= MS_NOATIME;
uid = sbi->sb_uid; gid = sbi->sb_gid;
umask = 0777 & ~sbi->sb_mode;
lowercase = sbi->sb_lowercase; conv = sbi->sb_conv;
eas = sbi->sb_eas; chk = sbi->sb_chk; chkdsk = sbi->sb_chkdsk;
errs = sbi->sb_err; timeshift = sbi->sb_timeshift;
if (!(o = parse_opts(data, &uid, &gid, &umask, &lowercase, &conv,
&eas, &chk, &errs, &chkdsk, &timeshift))) {
printk("HPFS: bad mount options.\n");
goto out_err;
}
if (o == 2) {
hpfs_help();
goto out_err;
}
if (timeshift != sbi->sb_timeshift) {
printk("HPFS: timeshift can't be changed using remount.\n");
goto out_err;
}
unmark_dirty(s);
sbi->sb_uid = uid; sbi->sb_gid = gid;
sbi->sb_mode = 0777 & ~umask;
sbi->sb_lowercase = lowercase; sbi->sb_conv = conv;
sbi->sb_eas = eas; sbi->sb_chk = chk; sbi->sb_chkdsk = chkdsk;
sbi->sb_err = errs; sbi->sb_timeshift = timeshift;
if (!(*flags & MS_RDONLY)) mark_dirty(s);
replace_mount_options(s, new_opts);
return 0;
out_err:
kfree(new_opts);
return -EINVAL;
}
/* Super operations */
static const struct super_operations hpfs_sops =
{
.alloc_inode = hpfs_alloc_inode,
.destroy_inode = hpfs_destroy_inode,
.delete_inode = hpfs_delete_inode,
.put_super = hpfs_put_super,
.statfs = hpfs_statfs,
.remount_fs = hpfs_remount_fs,
.show_options = generic_show_options,
};
static int hpfs_fill_super(struct super_block *s, void *options, int silent)
{
struct buffer_head *bh0, *bh1, *bh2;
struct hpfs_boot_block *bootblock;
struct hpfs_super_block *superblock;
struct hpfs_spare_block *spareblock;
struct hpfs_sb_info *sbi;
struct inode *root;
uid_t uid;
gid_t gid;
umode_t umask;
int lowercase, conv, eas, chk, errs, chkdsk, timeshift;
dnode_secno root_dno;
struct hpfs_dirent *de = NULL;
struct quad_buffer_head qbh;
int o;
save_mount_options(s, options);
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
s->s_fs_info = sbi;
sbi->sb_bmp_dir = NULL;
sbi->sb_cp_table = NULL;
init_MUTEX(&sbi->hpfs_creation_de);
uid = current_uid();
gid = current_gid();
umask = current_umask();
lowercase = 0;
conv = CONV_BINARY;
eas = 2;
chk = 1;
errs = 1;
chkdsk = 1;
timeshift = 0;
if (!(o = parse_opts(options, &uid, &gid, &umask, &lowercase, &conv,
&eas, &chk, &errs, &chkdsk, &timeshift))) {
printk("HPFS: bad mount options.\n");
goto bail0;
}
if (o==2) {
hpfs_help();
goto bail0;
}
/*sbi->sb_mounting = 1;*/
sb_set_blocksize(s, 512);
sbi->sb_fs_size = -1;
if (!(bootblock = hpfs_map_sector(s, 0, &bh0, 0))) goto bail1;
if (!(superblock = hpfs_map_sector(s, 16, &bh1, 1))) goto bail2;
if (!(spareblock = hpfs_map_sector(s, 17, &bh2, 0))) goto bail3;
/* Check magics */
if (/*bootblock->magic != BB_MAGIC
||*/ superblock->magic != SB_MAGIC
|| spareblock->magic != SP_MAGIC) {
if (!silent) printk("HPFS: Bad magic ... probably not HPFS\n");
goto bail4;
}
/* Check version */
if (!(s->s_flags & MS_RDONLY) &&
superblock->funcversion != 2 && superblock->funcversion != 3) {
printk("HPFS: Bad version %d,%d. Mount readonly to go around\n",
(int)superblock->version, (int)superblock->funcversion);
printk("HPFS: please try recent version of HPFS driver at http://artax.karlin.mff.cuni.cz/~mikulas/vyplody/hpfs/index-e.cgi and if it still can't understand this format, contact author - mikulas@artax.karlin.mff.cuni.cz\n");
goto bail4;
}
s->s_flags |= MS_NOATIME;
/* Fill superblock stuff */
s->s_magic = HPFS_SUPER_MAGIC;
s->s_op = &hpfs_sops;
sbi->sb_root = superblock->root;
sbi->sb_fs_size = superblock->n_sectors;
sbi->sb_bitmaps = superblock->bitmaps;
sbi->sb_dirband_start = superblock->dir_band_start;
sbi->sb_dirband_size = superblock->n_dir_band;
sbi->sb_dmap = superblock->dir_band_bitmap;
sbi->sb_uid = uid;
sbi->sb_gid = gid;
sbi->sb_mode = 0777 & ~umask;
sbi->sb_n_free = -1;
sbi->sb_n_free_dnodes = -1;
sbi->sb_lowercase = lowercase;
sbi->sb_conv = conv;
sbi->sb_eas = eas;
sbi->sb_chk = chk;
sbi->sb_chkdsk = chkdsk;
sbi->sb_err = errs;
sbi->sb_timeshift = timeshift;
sbi->sb_was_error = 0;
sbi->sb_cp_table = NULL;
sbi->sb_c_bitmap = -1;
sbi->sb_max_fwd_alloc = 0xffffff;
/* Load bitmap directory */
if (!(sbi->sb_bmp_dir = hpfs_load_bitmap_directory(s, superblock->bitmaps)))
goto bail4;
/* Check for general fs errors*/
if (spareblock->dirty && !spareblock->old_wrote) {
if (errs == 2) {
printk("HPFS: Improperly stopped, not mounted\n");
goto bail4;
}
hpfs_error(s, "improperly stopped");
}
if (!(s->s_flags & MS_RDONLY)) {
spareblock->dirty = 1;
spareblock->old_wrote = 0;
mark_buffer_dirty(bh2);
}
if (spareblock->hotfixes_used || spareblock->n_spares_used) {
if (errs >= 2) {
printk("HPFS: Hotfixes not supported here, try chkdsk\n");
mark_dirty(s);
goto bail4;
}
hpfs_error(s, "hotfixes not supported here, try chkdsk");
if (errs == 0) printk("HPFS: Proceeding, but your filesystem will be probably corrupted by this driver...\n");
else printk("HPFS: This driver may read bad files or crash when operating on disk with hotfixes.\n");
}
if (spareblock->n_dnode_spares != spareblock->n_dnode_spares_free) {
if (errs >= 2) {
printk("HPFS: Spare dnodes used, try chkdsk\n");
mark_dirty(s);
goto bail4;
}
hpfs_error(s, "warning: spare dnodes used, try chkdsk");
if (errs == 0) printk("HPFS: Proceeding, but your filesystem could be corrupted if you delete files or directories\n");
}
if (chk) {
unsigned a;
if (superblock->dir_band_end - superblock->dir_band_start + 1 != superblock->n_dir_band ||
superblock->dir_band_end < superblock->dir_band_start || superblock->n_dir_band > 0x4000) {
hpfs_error(s, "dir band size mismatch: dir_band_start==%08x, dir_band_end==%08x, n_dir_band==%08x",
superblock->dir_band_start, superblock->dir_band_end, superblock->n_dir_band);
goto bail4;
}
a = sbi->sb_dirband_size;
sbi->sb_dirband_size = 0;
if (hpfs_chk_sectors(s, superblock->dir_band_start, superblock->n_dir_band, "dir_band") ||
hpfs_chk_sectors(s, superblock->dir_band_bitmap, 4, "dir_band_bitmap") ||
hpfs_chk_sectors(s, superblock->bitmaps, 4, "bitmaps")) {
mark_dirty(s);
goto bail4;
}
sbi->sb_dirband_size = a;
} else printk("HPFS: You really don't want any checks? You are crazy...\n");
/* Load code page table */
if (spareblock->n_code_pages)
if (!(sbi->sb_cp_table = hpfs_load_code_page(s, spareblock->code_page_dir)))
printk("HPFS: Warning: code page support is disabled\n");
brelse(bh2);
brelse(bh1);
brelse(bh0);
root = iget_locked(s, sbi->sb_root);
if (!root)
goto bail0;
hpfs_init_inode(root);
hpfs_read_inode(root);
unlock_new_inode(root);
s->s_root = d_alloc_root(root);
if (!s->s_root) {
iput(root);
goto bail0;
}
hpfs_set_dentry_operations(s->s_root);
/*
* find the root directory's . pointer & finish filling in the inode
*/
root_dno = hpfs_fnode_dno(s, sbi->sb_root);
if (root_dno)
de = map_dirent(root, root_dno, "\001\001", 2, NULL, &qbh);
if (!de)
hpfs_error(s, "unable to find root dir");
else {
root->i_atime.tv_sec = local_to_gmt(s, de->read_date);
root->i_atime.tv_nsec = 0;
root->i_mtime.tv_sec = local_to_gmt(s, de->write_date);
root->i_mtime.tv_nsec = 0;
root->i_ctime.tv_sec = local_to_gmt(s, de->creation_date);
root->i_ctime.tv_nsec = 0;
hpfs_i(root)->i_ea_size = de->ea_size;
hpfs_i(root)->i_parent_dir = root->i_ino;
if (root->i_size == -1)
root->i_size = 2048;
if (root->i_blocks == -1)
root->i_blocks = 5;
hpfs_brelse4(&qbh);
}
return 0;
bail4: brelse(bh2);
bail3: brelse(bh1);
bail2: brelse(bh0);
bail1:
bail0:
kfree(sbi->sb_bmp_dir);
kfree(sbi->sb_cp_table);
s->s_fs_info = NULL;
kfree(sbi);
return -EINVAL;
}
static int hpfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_bdev(fs_type, flags, dev_name, data, hpfs_fill_super,
mnt);
}
static struct file_system_type hpfs_fs_type = {
.owner = THIS_MODULE,
.name = "hpfs",
.get_sb = hpfs_get_sb,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static int __init init_hpfs_fs(void)
{
int err = init_inodecache();
if (err)
goto out1;
err = register_filesystem(&hpfs_fs_type);
if (err)
goto out;
return 0;
out:
destroy_inodecache();
out1:
return err;
}
static void __exit exit_hpfs_fs(void)
{
unregister_filesystem(&hpfs_fs_type);
destroy_inodecache();
}
module_init(init_hpfs_fs)
module_exit(exit_hpfs_fs)
MODULE_LICENSE("GPL");
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