super.c

linux 内核源代码

/*
 *  linux/fs/hpfs/super.c
 *
 *  Mikulas Patocka ([e-mail]), 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);
	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_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(struct kmem_cache *cachep, 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 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;