super.c

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/*
 *  linux/fs/hpfs/super.c
 *
 *  Mikulas Patocka ([e-mail]), 1998-1999
 *
 *  mounting, unmounting, error handling
 */

#include <linux/string.h>
#include "hpfs_fn.h"
#include <linux/module.h>
#include <linux/init.h>

/* Mark the filesystem dirty, so that chkdsk checks it when os/2 booted */

static void mark_dirty(struct super_block *s)
{
	if (s->s_hpfs_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 = s->s_hpfs_chkdsk > 1 - s->s_hpfs_was_error;
		sb->old_wrote = s->s_hpfs_chkdsk >= 2 && !s->s_hpfs_was_error;
		mark_buffer_dirty(bh);
		brelse(bh);
	}
}

/* Filesystem error... */

#define ERR_BUF_SIZE 1024

void hpfs_error(struct super_block *s, char *m,...)
{
	char *buf;
	va_list l;
	va_start(l, m);
	if (!(buf = kmalloc(ERR_BUF_SIZE, GFP_KERNEL)))
		printk("HPFS: No memory for error message '%s'\n",m);
	else if (vsprintf(buf, m, l) >= ERR_BUF_SIZE)
		printk("HPFS: Grrrr... Kernel memory corrupted ... going on, but it'll crash very soon :-(\n");
	printk("HPFS: filesystem error: ");
	if (buf) printk("%s", buf);
	else printk("%s\n",m);
	if (!s->s_hpfs_was_error) {
		if (s->s_hpfs_err == 2) {
			printk("; crashing the system because you wanted it\n");
			mark_dirty(s);
			panic("HPFS panic");
		} else if (s->s_hpfs_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");
	if (buf) kfree(buf);
	s->s_hpfs_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;
}

void hpfs_put_super(struct super_block *s)
{
	if (s->s_hpfs_cp_table) kfree(s->s_hpfs_cp_table);
	if (s->s_hpfs_bmp_dir) kfree(s->s_hpfs_bmp_dir);
	unmark_dirty(s);
}

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 = (s->s_hpfs_fs_size + 0x3fff) >> 14;
	count = 0;
	for (n = 0; n < n_bands; n++)
		count += hpfs_count_one_bitmap(s, s->s_hpfs_bmp_dir[n]);
	return count;
}

int hpfs_statfs(struct super_block *s, struct statfs *buf)
{
	/*if (s->s_hpfs_n_free == -1) {*/
		s->s_hpfs_n_free = count_bitmaps(s);
		s->s_hpfs_n_free_dnodes = hpfs_count_one_bitmap(s, s->s_hpfs_dmap);
	/*}*/
	buf->f_type = s->s_magic;
	buf->f_bsize = 512;
	buf->f_blocks = s->s_hpfs_fs_size;
	buf->f_bfree = s->s_hpfs_n_free;
	buf->f_bavail = s->s_hpfs_n_free;
	buf->f_files = s->s_hpfs_dirband_size / 4;
	buf->f_ffree = s->s_hpfs_n_free_dnodes;
	buf->f_namelen = 254;
	return 0;
}

/* Super operations */

static struct super_operations hpfs_sops =
{
        read_inode:	hpfs_read_inode,
	delete_inode:	hpfs_delete_inode,
	put_super:	hpfs_put_super,
	statfs:		hpfs_statfs,
	remount_fs:	hpfs_remount_fs,
};

/*
 * A tiny parser for option strings, stolen from dosfs.
 *
 * Stolen again from read-only hpfs.
 */

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, *rhs;

	if (!opts)
		return 1;

	/*printk("Parsing opts: '%s'\n",opts);*/

	for (p = strtok(opts, ","); p != 0; p = strtok(0, ",")) {
		if ((rhs = strchr(p, '=')) != 0)
			*rhs++ = '\0';
		if (!strcmp(p, "help")) return 2;
		if (!strcmp(p, "uid")) {
			if (!rhs || !*rhs)
				return 0;
			*uid = simple_strtoul(rhs, &rhs, 0);
			if (*rhs)
				return 0;
		}
		else if (!strcmp(p, "gid")) {
			if (!rhs || !*rhs)
				return 0;
			*gid = simple_strtoul(rhs, &rhs, 0);
			if (*rhs)
				return 0;
		}
		else if (!strcmp(p, "umask")) {
			if (!rhs || !*rhs)
				return 0;
			*umask = simple_strtoul(rhs, &rhs, 8);
			if (*rhs)
				return 0;
		}
		else if (!strcmp(p, "timeshift")) {
			int m = 1;
			if (!rhs || !*rhs)
				return 0;
			if (*rhs == '-') m = -1;
			if (*rhs == '+' || *rhs == '-') rhs++;
			*timeshift = simple_strtoul(rhs, &rhs, 0) * m;
			if (*rhs)
				return 0;
		}
		else if (!strcmp(p, "case")) {
			if (!rhs || !*rhs)
				return 0;
			if (!strcmp(rhs, "lower"))
				*lowercase = 1;
			else if (!strcmp(rhs, "asis"))
				*lowercase = 0;
			else
				return 0;
		}
		else if (!strcmp(p, "conv")) {
			if (!rhs || !*rhs)
				return 0;
			if (!strcmp(rhs, "binary"))
				*conv = CONV_BINARY;
			else if (!strcmp(rhs, "text"))
				*conv = CONV_TEXT;
			else if (!strcmp(rhs, "auto"))
				*conv = CONV_AUTO;
			else
				return 0;
		}
		else if (!strcmp(p, "check")) {
			if (!rhs || !*rhs)
				return 0;
			if (!strcmp(rhs, "none"))
				*chk = 0;
			else if (!strcmp(rhs, "normal"))
				*chk = 1;
			else if (!strcmp(rhs, "strict"))
				*chk = 2;
			else
				return 0;
		}
		else if (!strcmp(p, "errors")) {
			if (!rhs || !*rhs)
				return 0;
			if (!strcmp(rhs, "continue"))
				*errs = 0;
			else if (!strcmp(rhs, "remount-ro"))
				*errs = 1;
			else if (!strcmp(rhs, "panic"))
				*errs = 2;
			else
				return 0;
		}
		else if (!strcmp(p, "eas")) {
			if (!rhs || !*rhs)
				return 0;
			if (!strcmp(rhs, "no"))
				*eas = 0;
			else if (!strcmp(rhs, "ro"))
				*eas = 1;
			else if (!strcmp(rhs, "rw"))
				*eas = 2;
			else
				return 0;
		}
		else if (!strcmp(p, "chkdsk")) {
			if (!rhs || !*rhs)
				return 0;
			if (!strcmp(rhs, "no"))
				*chkdsk = 0;
			else if (!strcmp(rhs, "errors"))
				*chkdsk = 1;
			else if (!strcmp(rhs, "always"))
				*chkdsk = 2;
			else
				return 0;
		}
		else
			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\