inode.c

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/*
 *  fs/bfs/inode.c
 *  BFS superblock and inode operations.
 *  Copyright (C) 1999-2006 Tigran Aivazian <[email protected]>
 *  From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds.
 *
 *      Made endianness-clean by Andrew Stribblehill <[email protected]>, 2005.
 */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/vfs.h>
#include <linux/writeback.h>
#include <asm/uaccess.h>
#include "bfs.h"

MODULE_AUTHOR("Tigran Aivazian <[email protected]>");
MODULE_DESCRIPTION("SCO UnixWare BFS filesystem for Linux");
MODULE_LICENSE("GPL");

#undef DEBUG

#ifdef DEBUG
#define dprintf(x...)   printf(x)
#else
#define dprintf(x...)
#endif

void dump_imap(const char *prefix, struct super_block *s);

struct inode *bfs_iget(struct super_block *sb, unsigned long ino)
{
    struct bfs_inode *di;
    struct inode *inode;
    struct buffer_head *bh;
    int block, off;

    inode = iget_locked(sb, ino);
    if (IS_ERR(inode))
        return ERR_PTR(-ENOMEM);
    if (!(inode->i_state & I_NEW))
        return inode;

    if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
        printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
        goto error;
    }

    block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
    bh = sb_bread(inode->i_sb, block);
    if (!bh) {
        printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
                                    ino);
        goto error;
    }

    off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
    di = (struct bfs_inode *)bh->b_data + off;

    inode->i_mode = 0x0000FFFF & le32_to_cpu(di->i_mode);
    if (le32_to_cpu(di->i_vtype) == BFS_VDIR) {
        inode->i_mode |= S_IFDIR;
        inode->i_op = &bfs_dir_inops;
        inode->i_fop = &bfs_dir_operations;
    } else if (le32_to_cpu(di->i_vtype) == BFS_VREG) {
        inode->i_mode |= S_IFREG;
        inode->i_op = &bfs_file_inops;
        inode->i_fop = &bfs_file_operations;
        inode->i_mapping->a_ops = &bfs_aops;
    }

    BFS_I(inode)->i_sblock =  le32_to_cpu(di->i_sblock);
    BFS_I(inode)->i_eblock =  le32_to_cpu(di->i_eblock);
    BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino);
    i_uid_write(inode, le32_to_cpu(di->i_uid));
    i_gid_write(inode,  le32_to_cpu(di->i_gid));
    set_nlink(inode, le32_to_cpu(di->i_nlink));
    inode->i_size = BFS_FILESIZE(di);
    inode->i_blocks = BFS_FILEBLOCKS(di);
    inode->i_atime.tv_sec =  le32_to_cpu(di->i_atime);
    inode->i_mtime.tv_sec =  le32_to_cpu(di->i_mtime);
    inode->i_ctime.tv_sec =  le32_to_cpu(di->i_ctime);
    inode->i_atime.tv_nsec = 0;
    inode->i_mtime.tv_nsec = 0;
    inode->i_ctime.tv_nsec = 0;

    brelse(bh);
    unlock_new_inode(inode);
    return inode;

error:
    iget_failed(inode);
    return ERR_PTR(-EIO);
}

static struct bfs_inode *find_inode(struct super_block *sb, u16 ino, struct buffer_head **p)
{
    if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(sb)->si_lasti)) {
        printf("Bad inode number %s:%08x\n", sb->s_id, ino);
        return ERR_PTR(-EIO);
    }

    ino -= BFS_ROOT_INO;

    *p = sb_bread(sb, 1 + ino / BFS_INODES_PER_BLOCK);
    if (!*p) {
        printf("Unable to read inode %s:%08x\n", sb->s_id, ino);
        return ERR_PTR(-EIO);
    }

    return (struct bfs_inode *)(*p)->b_data +  ino % BFS_INODES_PER_BLOCK;
}

static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
    struct bfs_sb_info *info = BFS_SB(inode->i_sb);
    unsigned int ino = (u16)inode->i_ino;
        unsigned long i_sblock;
    struct bfs_inode *di;
    struct buffer_head *bh;
    int err = 0;

        dprintf("ino=%08x\n", ino);

    di = find_inode(inode->i_sb, ino, &bh);
    if (IS_ERR(di))
        return PTR_ERR(di);

    mutex_lock(&info->bfs_lock);

    if (ino == BFS_ROOT_INO)
        di->i_vtype = cpu_to_le32(BFS_VDIR);
    else
        di->i_vtype = cpu_to_le32(BFS_VREG);

    di->i_ino = cpu_to_le16(ino);
    di->i_mode = cpu_to_le32(inode->i_mode);
    di->i_uid = cpu_to_le32(i_uid_read(inode));
    di->i_gid = cpu_to_le32(i_gid_read(inode));
    di->i_nlink = cpu_to_le32(inode->i_nlink);
    di->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
    di->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
    di->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
        i_sblock = BFS_I(inode)->i_sblock;
    di->i_sblock = cpu_to_le32(i_sblock);
    di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock);
    di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);

    mark_buffer_dirty(bh);
    if (wbc->sync_mode == WB_SYNC_ALL) {
        sync_dirty_buffer(bh);
        if (buffer_req(bh) && !buffer_uptodate(bh))
            err = -EIO;
    }
    brelse(bh);
    mutex_unlock(&info->bfs_lock);
    return err;
}

static void bfs_evict_inode(struct inode *inode)
{
    unsigned long ino = inode->i_ino;
    struct bfs_inode *di;
    struct buffer_head *bh;
    struct super_block *s = inode->i_sb;
    struct bfs_sb_info *info = BFS_SB(s);
    struct bfs_inode_info *bi = BFS_I(inode);

    dprintf("ino=%08lx\n", ino);

    truncate_inode_pages(&inode->i_data, 0);
    invalidate_inode_buffers(inode);
    clear_inode(inode);

    if (inode->i_nlink)
        return;

    di = find_inode(s, inode->i_ino, &bh);
    if (IS_ERR(di))
        return;

    mutex_lock(&info->bfs_lock);
    /* clear on-disk inode */
    memset(di, 0, sizeof(struct bfs_inode));
    mark_buffer_dirty(bh);
    brelse(bh);

        if (bi->i_dsk_ino) {
        if (bi->i_sblock)
            info->si_freeb += bi->i_eblock + 1 - bi->i_sblock;
        info->si_freei++;
        clear_bit(ino, info->si_imap);
        dump_imap("delete_inode", s);
        }

    /*
     * If this was the last file, make the previous block
     * "last block of the last file" even if there is no
     * real file there, saves us 1 gap.
     */
    if (info->si_lf_eblk == bi->i_eblock)
        info->si_lf_eblk = bi->i_sblock - 1;
    mutex_unlock(&info->bfs_lock);
}

static void bfs_put_super(struct super_block *s)
{
    struct bfs_sb_info *info = BFS_SB(s);

    if (!info)
        return;

    mutex_destroy(&info->bfs_lock);
    kfree(info->si_imap);
    kfree(info);
    s->s_fs_info = NULL;
}

static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
    struct super_block *s = dentry->d_sb;
    struct bfs_sb_info *info = BFS_SB(s);
    u64 id = huge_encode_dev(s->s_bdev->bd_dev);
    buf->f_type = BFS_MAGIC;
    buf->f_bsize = s->s_blocksize;
    buf->f_blocks = info->si_blocks;
    buf->f_bfree = buf->f_bavail = info->si_freeb;
    buf->f_files = info->si_lasti + 1 - BFS_ROOT_INO;
    buf->f_ffree = info->si_freei;
    buf->f_fsid.val[0] = (u32)id;
    buf->f_fsid.val[1] = (u32)(id >> 32);
    buf->f_namelen = BFS_NAMELEN;
    return 0;
}

static struct kmem_cache *bfs_inode_cachep;

static struct inode *bfs_alloc_inode(struct super_block *sb)
{
    struct bfs_inode_info *bi;
    bi = kmem_cache_alloc(bfs_inode_cachep, GFP_KERNEL);
    if (!bi)
        return NULL;
    return &bi->vfs_inode;
}

static void bfs_i_callback(struct rcu_head *head)
{
    struct inode *inode = container_of(head, struct inode, i_rcu);
    kmem_cache_free(bfs_inode_cachep, BFS_I(inode));
}

static void bfs_destroy_inode(struct inode *inode)
{
    call_rcu(&inode->i_rcu, bfs_i_callback);
}

static void init_once(void *foo)
{
    struct bfs_inode_info *bi = foo;

    inode_init_once(&bi->vfs_inode);
}

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

static void destroy_inodecache(void)
{
    /*
     * Make sure all delayed rcu free inodes are flushed before we
     * destroy cache.
     */
    rcu_barrier();
    kmem_cache_destroy(bfs_inode_cachep);
}

static const struct super_operations bfs_sops = {
    .alloc_inode    = bfs_alloc_inode,
    .destroy_inode  = bfs_destroy_inode,
    .write_inode    = bfs_write_inode,
    .evict_inode    = bfs_evict_inode,
    .put_super  = bfs_put_super,
    .statfs     = bfs_statfs,
};

void dump_imap(const char *prefix, struct super_block *s)
{
#ifdef DEBUG
    int i;
    char *tmpbuf = (char *)get_zeroed_page(GFP_KERNEL);

    if (!tmpbuf)
        return;
    for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
        if (i > PAGE_SIZE - 100) break;
        if (test_bit(i, BFS_SB(s)->si_imap))
            strcat(tmpbuf, "1");
        else
            strcat(tmpbuf, "0");
    }
    printf("BFS-fs: %s: lasti=%08lx <%s>\n",
                prefix, BFS_SB(s)->si_lasti, tmpbuf);
    free_page((unsigned long)tmpbuf);
#endif
}

static int bfs_fill_super(struct super_block *s, void *data, int silent)
{
    struct buffer_head *bh, *sbh;
    struct bfs_super_block *bfs_sb;
    struct inode *inode;
    unsigned i, imap_len;
    struct bfs_sb_info *info;
    int ret = -EINVAL;
    unsigned long i_sblock, i_eblock, i_eoff, s_size;

    info = kzalloc(sizeof(*info), GFP_KERNEL);
    if (!info)
        return -ENOMEM;
    mutex_init(&info->bfs_lock);
    s->s_fs_info = info;

    sb_set_blocksize(s, BFS_BSIZE);

    sbh = sb_bread(s, 0);
    if (!sbh)
        goto out;
    bfs_sb = (struct bfs_super_block *)sbh->b_data;
    if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) {
        if (!silent)
            printf("No BFS filesystem on %s (magic=%08x)\n", 
                s->s_id,  le32_to_cpu(bfs_sb->s_magic));
        goto out1;
    }
    if (BFS_UNCLEAN(bfs_sb, s) && !silent)
        printf("%s is unclean, continuing\n", s->s_id);

    s->s_magic = BFS_MAGIC;

    if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) {
        printf("Superblock is corrupted\n");
        goto out1;
    }

    info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) /
                    sizeof(struct bfs_inode)
                    + BFS_ROOT_INO - 1;
    imap_len = (info->si_lasti / 8) + 1;
    info->si_imap = kzalloc(imap_len, GFP_KERNEL);
    if (!info->si_imap)
        goto out1;
    for (i = 0; i < BFS_ROOT_INO; i++)
        set_bit(i, info->si_imap);

    s->s_op = &bfs_sops;
    inode = bfs_iget(s, BFS_ROOT_INO);
    if (IS_ERR(inode)) {
        ret = PTR_ERR(inode);
        goto out2;
    }
    s->s_root = d_make_root(inode);
    if (!s->s_root) {
        ret = -ENOMEM;
        goto out2;
    }

    info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS;
    info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1
            - le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
    info->si_freei = 0;
    info->si_lf_eblk = 0;

    /* can we read the last block? */
    bh = sb_bread(s, info->si_blocks - 1);
    if (!bh) {
        printf("Last block not available: %lu\n", info->si_blocks - 1);
        ret = -EIO;
        goto out3;
    }
    brelse(bh);

    bh = NULL;
    for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
        struct bfs_inode *di;
        int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
        int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
        unsigned long eblock;

        if (!off) {
            brelse(bh);
            bh = sb_bread(s, block);
        }

        if (!bh)
            continue;

        di = (struct bfs_inode *)bh->b_data + off;

        /* test if filesystem is not corrupted */

        i_eoff = le32_to_cpu(di->i_eoffset);
        i_sblock = le32_to_cpu(di->i_sblock);
        i_eblock = le32_to_cpu(di->i_eblock);
        s_size = le32_to_cpu(bfs_sb->s_end);

        if (i_sblock > info->si_blocks ||
            i_eblock > info->si_blocks ||
            i_sblock > i_eblock ||
            i_eoff > s_size ||
            i_sblock * BFS_BSIZE > i_eoff) {

            printf("Inode 0x%08x corrupted\n", i);

            brelse(bh);
            ret = -EIO;
            goto out3;
        }

        if (!di->i_ino) {
            info->si_freei++;
            continue;
        }
        set_bit(i, info->si_imap);
        info->si_freeb -= BFS_FILEBLOCKS(di);

        eblock =  le32_to_cpu(di->i_eblock);
        if (eblock > info->si_lf_eblk)
            info->si_lf_eblk = eblock;
    }
    brelse(bh);
    brelse(sbh);
    dump_imap("read_super", s);
    return 0;

out3:
    dput(s->s_root);
    s->s_root = NULL;
out2:
    kfree(info->si_imap);
out1:
    brelse(sbh);
out:
    mutex_destroy(&info->bfs_lock);
    kfree(info);
    s->s_fs_info = NULL;
    return ret;
}

static struct dentry *bfs_mount(struct file_system_type *fs_type,
    int flags, const char *dev_name, void *data)
{
    return mount_bdev(fs_type, flags, dev_name, data, bfs_fill_super);
}

static struct file_system_type bfs_fs_type = {
    .owner      = THIS_MODULE,
    .name       = "bfs",
    .mount      = bfs_mount,
    .kill_sb    = kill_block_super,
    .fs_flags   = FS_REQUIRES_DEV,
};

static int __init init_bfs_fs(void)
{
    int err = init_inodecache();
    if (err)
        goto out1;
        err = register_filesystem(&bfs_fs_type);
    if (err)
        goto out;
    return 0;
out:
    destroy_inodecache();
out1:
    return err;
}

static void __exit exit_bfs_fs(void)
{
    unregister_filesystem(&bfs_fs_type);
    destroy_inodecache();
}

module_init(init_bfs_fs)
module_exit(exit_bfs_fs)