Subversion Repositories or1k

/*

 * super.c

 *

 * Copyright (c) 1999 Al Smith

 *

 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.

 */

#include <linux/init.h>

#include <linux/module.h>

#include <linux/locks.h>

#include <linux/efs_fs.h>

#include <linux/efs_vh.h>

#include <linux/efs_fs_sb.h>

static DECLARE_FSTYPE_DEV(efs_fs_type, "efs", efs_read_super);

static struct super_operations efs_superblock_operations = {

        read_inode:     efs_read_inode,

        statfs:         efs_statfs,

};

static int __init init_efs_fs(void) {

        printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");

        return register_filesystem(&efs_fs_type);

}

static void __exit exit_efs_fs(void) {

        unregister_filesystem(&efs_fs_type);

}

EXPORT_NO_SYMBOLS;

module_init(init_efs_fs)

module_exit(exit_efs_fs)

static efs_block_t efs_validate_vh(struct volume_header *vh) {

        int             i;

        unsigned int    cs, csum, *ui;

        efs_block_t     sblock = 0; /* shuts up gcc */

        struct pt_types *pt_entry;

        int             pt_type, slice = -1;

        if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {

                /*

                 * assume that we're dealing with a partition and allow

                 * read_super() to try and detect a valid superblock

                 * on the next block.

                 */

                return 0;

        }

        ui = ((unsigned int *) (vh + 1)) - 1;

        for(csum = 0; ui >= ((unsigned int *) vh);) {

                cs = *ui--;

                csum += be32_to_cpu(cs);

        }

        if (csum) {

                printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");

                return 0;

        }

#ifdef DEBUG

        printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);

        for(i = 0; i < NVDIR; i++) {

                int     j;

                char    name[VDNAMESIZE+1];

                for(j = 0; j < VDNAMESIZE; j++) {

                        name[j] = vh->vh_vd[i].vd_name[j];

                }

                name[j] = (char) 0;

                if (name[0]) {

                        printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",

                                name,

                                (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),

                                (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));

                }

        }

#endif

        for(i = 0; i < NPARTAB; i++) {

                pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);

                for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {

                        if (pt_type == pt_entry->pt_type) break;

                }

#ifdef DEBUG

                if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {

                        printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",

                                i,

                                (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),

                                (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),

                                pt_type,

                                (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");

                }

#endif

                if (IS_EFS(pt_type)) {

                        sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);

                        slice = i;

                }

        }

        if (slice == -1) {

                printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");

#ifdef DEBUG

        } else {

                printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",

                        slice,

                        (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",

                        sblock);

#endif

        }

        return(sblock);

}

static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {

        if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic))) return -1;

        sb->fs_magic     = be32_to_cpu(super->fs_magic);

        sb->total_blocks = be32_to_cpu(super->fs_size);

        sb->first_block  = be32_to_cpu(super->fs_firstcg);

        sb->group_size   = be32_to_cpu(super->fs_cgfsize);

        sb->data_free    = be32_to_cpu(super->fs_tfree);

        sb->inode_free   = be32_to_cpu(super->fs_tinode);

        sb->inode_blocks = be16_to_cpu(super->fs_cgisize);

        sb->total_groups = be16_to_cpu(super->fs_ncg);

        return 0;

}

struct super_block *efs_read_super(struct super_block *s, void *d, int silent) {

        kdev_t dev = s->s_dev;

        struct efs_sb_info *sb;

        struct buffer_head *bh;

        sb = SUPER_INFO(s);

        s->s_magic              = EFS_SUPER_MAGIC;

        s->s_blocksize          = EFS_BLOCKSIZE;

        s->s_blocksize_bits     = EFS_BLOCKSIZE_BITS;

        if( set_blocksize(dev, EFS_BLOCKSIZE) < 0)

        {

                printk(KERN_ERR "EFS: device does not support %d byte blocks\n",

                        EFS_BLOCKSIZE);

                goto out_no_fs_ul;

        }

        /* read the vh (volume header) block */

        bh = sb_bread(s, 0);

        if (!bh) {

                printk(KERN_ERR "EFS: cannot read volume header\n");

                goto out_no_fs_ul;

        }

        /*

         * if this returns zero then we didn't find any partition table.

         * this isn't (yet) an error - just assume for the moment that

         * the device is valid and go on to search for a superblock.

         */

        sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);

        brelse(bh);

        if (sb->fs_start == -1) {

                goto out_no_fs_ul;

        }

        bh = sb_bread(s, sb->fs_start + EFS_SUPER);

        if (!bh) {

                printk(KERN_ERR "EFS: cannot read superblock\n");

                goto out_no_fs_ul;

        }

        if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {

#ifdef DEBUG

                printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);

#endif

                brelse(bh);

                goto out_no_fs_ul;

        }

        brelse(bh);

        if (!(s->s_flags & MS_RDONLY)) {

#ifdef DEBUG

                printk(KERN_INFO "EFS: forcing read-only mode\n");

#endif

                s->s_flags |= MS_RDONLY;

        }

        s->s_op   = &efs_superblock_operations;

        s->s_root = d_alloc_root(iget(s, EFS_ROOTINODE));

        if (!(s->s_root)) {

                printk(KERN_ERR "EFS: get root inode failed\n");

                goto out_no_fs;

        }

        return(s);

out_no_fs_ul:

out_no_fs:

        return(NULL);

}

int efs_statfs(struct super_block *s, struct statfs *buf) {

        struct efs_sb_info *sb = SUPER_INFO(s);

        buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */

        buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */

        buf->f_blocks  = sb->total_groups *     /* total data blocks */

                        (sb->group_size - sb->inode_blocks);

        buf->f_bfree   = sb->data_free;         /* free data blocks */

        buf->f_bavail  = sb->data_free;         /* free blocks for non-root */

        buf->f_files   = sb->total_groups *     /* total inodes */

                        sb->inode_blocks *

                        (EFS_BLOCKSIZE / sizeof(struct efs_dinode));

        buf->f_ffree   = sb->inode_free;        /* free inodes */

        buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */

        buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */

        buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */

        return 0;

}