[funini.com] -> [kei@sodan] -> Kernel Reading

root/fs/efs/super.c

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. efs_get_sb
  2. efs_alloc_inode
  3. efs_destroy_inode
  4. init_once
  5. init_inodecache
  6. destroy_inodecache
  7. efs_put_super
  8. efs_remount
  9. init_efs_fs
  10. exit_efs_fs
  11. module_init
  12. efs_validate_super
  13. efs_fill_super
  14. efs_statfs

/*
 * 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/exportfs.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include <linux/vfs.h>

#include "efs.h"
#include <linux/efs_vh.h>
#include <linux/efs_fs_sb.h>

static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
static int efs_fill_super(struct super_block *s, void *d, int silent);

static int efs_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, efs_fill_super, mnt);
}

static struct file_system_type efs_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "efs",
        .get_sb         = efs_get_sb,
        .kill_sb        = kill_block_super,
        .fs_flags       = FS_REQUIRES_DEV,
};

static struct pt_types sgi_pt_types[] = {
        {0x00,          "SGI vh"},
        {0x01,          "SGI trkrepl"},
        {0x02,          "SGI secrepl"},
        {0x03,          "SGI raw"},
        {0x04,          "SGI bsd"},
        {SGI_SYSV,      "SGI sysv"},
        {0x06,          "SGI vol"},
        {SGI_EFS,       "SGI efs"},
        {0x08,          "SGI lv"},
        {0x09,          "SGI rlv"},
        {0x0A,          "SGI xfs"},
        {0x0B,          "SGI xfslog"},
        {0x0C,          "SGI xlv"},
        {0x82,          "Linux swap"},
        {0x83,          "Linux native"},
        {0,             NULL}
};


static struct kmem_cache * efs_inode_cachep;

static struct inode *efs_alloc_inode(struct super_block *sb)
{
        struct efs_inode_info *ei;
        ei = (struct efs_inode_info *)kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
        if (!ei)
                return NULL;
        return &ei->vfs_inode;
}

static void efs_destroy_inode(struct inode *inode)
{
        kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
}

static void init_once(void *foo)
{
        struct efs_inode_info *ei = (struct efs_inode_info *) foo;

        inode_init_once(&ei->vfs_inode);
}

static int init_inodecache(void)
{
        efs_inode_cachep = kmem_cache_create("efs_inode_cache",
                                sizeof(struct efs_inode_info),
                                0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
                                init_once);
        if (efs_inode_cachep == NULL)
                return -ENOMEM;
        return 0;
}

static void destroy_inodecache(void)
{
        kmem_cache_destroy(efs_inode_cachep);
}

static void efs_put_super(struct super_block *s)
{
        kfree(s->s_fs_info);
        s->s_fs_info = NULL;
}

static int efs_remount(struct super_block *sb, int *flags, char *data)
{
        *flags |= MS_RDONLY;
        return 0;
}

static const struct super_operations efs_superblock_operations = {
        .alloc_inode    = efs_alloc_inode,
        .destroy_inode  = efs_destroy_inode,
        .put_super      = efs_put_super,
        .statfs         = efs_statfs,
        .remount_fs     = efs_remount,
};

static const struct export_operations efs_export_ops = {
        .fh_to_dentry   = efs_fh_to_dentry,
        .fh_to_parent   = efs_fh_to_parent,
        .get_parent     = efs_get_parent,
};

static int __init init_efs_fs(void) {
        int err;
        printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
        err = init_inodecache();
        if (err)
                goto out1;
        err = register_filesystem(&efs_fs_type);
        if (err)
                goto out;
        return 0;
out:
        destroy_inodecache();
out1:
        return err;
}

static void __exit exit_efs_fs(void) {
        unregister_filesystem(&efs_fs_type);
        destroy_inodecache();
}

module_init(init_efs_fs)
module_exit(exit_efs_fs)

static efs_block_t efs_validate_vh(struct volume_header *vh) {
        int             i;
        __be32          cs, *ui;
        int             csum;
        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 = ((__be32 *) (vh + 1)) - 1;
        for(csum = 0; ui >= ((__be32 *) 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;    
}

static int efs_fill_super(struct super_block *s, void *d, int silent)
{
        struct efs_sb_info *sb;
        struct buffer_head *bh;
        struct inode *root;
        int ret = -EINVAL;

        sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
        if (!sb)
                return -ENOMEM;
        s->s_fs_info = sb;
 
        s->s_magic              = EFS_SUPER_MAGIC;
        if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
                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_export_op = &efs_export_ops;
        root = efs_iget(s, EFS_ROOTINODE);
        if (IS_ERR(root)) {
                printk(KERN_ERR "EFS: get root inode failed\n");
                ret = PTR_ERR(root);
                goto out_no_fs;
        }

        s->s_root = d_alloc_root(root);
        if (!(s->s_root)) {
                printk(KERN_ERR "EFS: get root dentry failed\n");
                iput(root);
                ret = -ENOMEM;
                goto out_no_fs;
        }

        return 0;

out_no_fs_ul:
out_no_fs:
        s->s_fs_info = NULL;
        kfree(sb);
        return ret;
}

static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
        struct efs_sb_info *sb = SUPER_INFO(dentry->d_sb);

        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_namelen = EFS_MAXNAMELEN;        /* max filename length */

        return 0;
}


/* [<][>][^][v][top][bottom][index][help] */

[funini.com] -> [kei@sodan] -> Kernel Reading