amigaffs.c

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/*
 *  linux/fs/affs/amigaffs.c
 *
 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
 *
 *  (C) 1993  Ray Burr - Amiga FFS filesystem.
 *
 *  Please send bug reports to: [email protected]
 */

#include "affs.h"

extern struct timezone sys_tz;

static char ErrorBuffer[256];

/*
 * Functions for accessing Amiga-FFS structures.
 */


/* Insert a header block bh into the directory dir
 * caller must hold AFFS_DIR->i_hash_lock!
 */

int
affs_insert_hash(struct inode *dir, struct buffer_head *bh)
{
    struct super_block *sb = dir->i_sb;
    struct buffer_head *dir_bh;
    u32 ino, hash_ino;
    int offset;

    ino = bh->b_blocknr;
    offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);

    pr_debug("AFFS: insert_hash(dir=%u, ino=%d)\n", (u32)dir->i_ino, ino);

    dir_bh = affs_bread(sb, dir->i_ino);
    if (!dir_bh)
        return -EIO;

    hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
    while (hash_ino) {
        affs_brelse(dir_bh);
        dir_bh = affs_bread(sb, hash_ino);
        if (!dir_bh)
            return -EIO;
        hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
    }
    AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
    AFFS_TAIL(sb, bh)->hash_chain = 0;
    affs_fix_checksum(sb, bh);

    if (dir->i_ino == dir_bh->b_blocknr)
        AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
    else
        AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);

    affs_adjust_checksum(dir_bh, ino);
    mark_buffer_dirty_inode(dir_bh, dir);
    affs_brelse(dir_bh);

    dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
    dir->i_version++;
    mark_inode_dirty(dir);

    return 0;
}

/* Remove a header block from its directory.
 * caller must hold AFFS_DIR->i_hash_lock!
 */

int
affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
{
    struct super_block *sb;
    struct buffer_head *bh;
    u32 rem_ino, hash_ino;
    __be32 ino;
    int offset, retval;

    sb = dir->i_sb;
    rem_ino = rem_bh->b_blocknr;
    offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
    pr_debug("AFFS: remove_hash(dir=%d, ino=%d, hashval=%d)\n", (u32)dir->i_ino, rem_ino, offset);

    bh = affs_bread(sb, dir->i_ino);
    if (!bh)
        return -EIO;

    retval = -ENOENT;
    hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
    while (hash_ino) {
        if (hash_ino == rem_ino) {
            ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
            if (dir->i_ino == bh->b_blocknr)
                AFFS_HEAD(bh)->table[offset] = ino;
            else
                AFFS_TAIL(sb, bh)->hash_chain = ino;
            affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
            mark_buffer_dirty_inode(bh, dir);
            AFFS_TAIL(sb, rem_bh)->parent = 0;
            retval = 0;
            break;
        }
        affs_brelse(bh);
        bh = affs_bread(sb, hash_ino);
        if (!bh)
            return -EIO;
        hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
    }

    affs_brelse(bh);

    dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
    dir->i_version++;
    mark_inode_dirty(dir);

    return retval;
}

static void
affs_fix_dcache(struct inode *inode, u32 entry_ino)
{
    struct dentry *dentry;
    struct hlist_node *p;
    spin_lock(&inode->i_lock);
    hlist_for_each_entry(dentry, p, &inode->i_dentry, d_alias) {
        if (entry_ino == (u32)(long)dentry->d_fsdata) {
            dentry->d_fsdata = (void *)inode->i_ino;
            break;
        }
    }
    spin_unlock(&inode->i_lock);
}


/* Remove header from link chain */

static int
affs_remove_link(struct dentry *dentry)
{
    struct inode *dir, *inode = dentry->d_inode;
    struct super_block *sb = inode->i_sb;
    struct buffer_head *bh = NULL, *link_bh = NULL;
    u32 link_ino, ino;
    int retval;

    pr_debug("AFFS: remove_link(key=%ld)\n", inode->i_ino);
    retval = -EIO;
    bh = affs_bread(sb, inode->i_ino);
    if (!bh)
        goto done;

    link_ino = (u32)(long)dentry->d_fsdata;
    if (inode->i_ino == link_ino) {
        /* we can't remove the head of the link, as its blocknr is still used as ino,
         * so we remove the block of the first link instead.
         */ 
        link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
        link_bh = affs_bread(sb, link_ino);
        if (!link_bh)
            goto done;

        dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
        if (IS_ERR(dir)) {
            retval = PTR_ERR(dir);
            goto done;
        }

        affs_lock_dir(dir);
        /*
         * if there's a dentry for that block, make it
         * refer to inode itself.
         */
        affs_fix_dcache(inode, link_ino);
        retval = affs_remove_hash(dir, link_bh);
        if (retval) {
            affs_unlock_dir(dir);
            goto done;
        }
        mark_buffer_dirty_inode(link_bh, inode);

        memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
        retval = affs_insert_hash(dir, bh);
        if (retval) {
            affs_unlock_dir(dir);
            goto done;
        }
        mark_buffer_dirty_inode(bh, inode);

        affs_unlock_dir(dir);
        iput(dir);
    } else {
        link_bh = affs_bread(sb, link_ino);
        if (!link_bh)
            goto done;
    }

    while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
        if (ino == link_ino) {
            __be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
            AFFS_TAIL(sb, bh)->link_chain = ino2;
            affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
            mark_buffer_dirty_inode(bh, inode);
            retval = 0;
            /* Fix the link count, if bh is a normal header block without links */
            switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
            case ST_LINKDIR:
            case ST_LINKFILE:
                break;
            default:
                if (!AFFS_TAIL(sb, bh)->link_chain)
                    set_nlink(inode, 1);
            }
            affs_free_block(sb, link_ino);
            goto done;
        }
        affs_brelse(bh);
        bh = affs_bread(sb, ino);
        if (!bh)
            goto done;
    }
    retval = -ENOENT;
done:
    affs_brelse(link_bh);
    affs_brelse(bh);
    return retval;
}


static int
affs_empty_dir(struct inode *inode)
{
    struct super_block *sb = inode->i_sb;
    struct buffer_head *bh;
    int retval, size;

    retval = -EIO;
    bh = affs_bread(sb, inode->i_ino);
    if (!bh)
        goto done;

    retval = -ENOTEMPTY;
    for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
        if (AFFS_HEAD(bh)->table[size])
            goto not_empty;
    retval = 0;
not_empty:
    affs_brelse(bh);
done:
    return retval;
}


/* Remove a filesystem object. If the object to be removed has
 * links to it, one of the links must be changed to inherit
 * the file or directory. As above, any inode will do.
 * The buffer will not be freed. If the header is a link, the
 * block will be marked as free.
 * This function returns a negative error number in case of
 * an error, else 0 if the inode is to be deleted or 1 if not.
 */

int
affs_remove_header(struct dentry *dentry)
{
    struct super_block *sb;
    struct inode *inode, *dir;
    struct buffer_head *bh = NULL;
    int retval;

    dir = dentry->d_parent->d_inode;
    sb = dir->i_sb;

    retval = -ENOENT;
    inode = dentry->d_inode;
    if (!inode)
        goto done;

    pr_debug("AFFS: remove_header(key=%ld)\n", inode->i_ino);
    retval = -EIO;
    bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
    if (!bh)
        goto done;

    affs_lock_link(inode);
    affs_lock_dir(dir);
    switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
    case ST_USERDIR:
        /* if we ever want to support links to dirs
         * i_hash_lock of the inode must only be
         * taken after some checks
         */
        affs_lock_dir(inode);
        retval = affs_empty_dir(inode);
        affs_unlock_dir(inode);
        if (retval)
            goto done_unlock;
        break;
    default:
        break;
    }

    retval = affs_remove_hash(dir, bh);
    if (retval)
        goto done_unlock;
    mark_buffer_dirty_inode(bh, inode);

    affs_unlock_dir(dir);

    if (inode->i_nlink > 1)
        retval = affs_remove_link(dentry);
    else
        clear_nlink(inode);
    affs_unlock_link(inode);
    inode->i_ctime = CURRENT_TIME_SEC;
    mark_inode_dirty(inode);

done:
    affs_brelse(bh);
    return retval;

done_unlock:
    affs_unlock_dir(dir);
    affs_unlock_link(inode);
    goto done;
}

/* Checksum a block, do various consistency checks and optionally return
   the blocks type number.  DATA points to the block.  If their pointers
   are non-null, *PTYPE and *STYPE are set to the primary and secondary
   block types respectively, *HASHSIZE is set to the size of the hashtable
   (which lets us calculate the block size).
   Returns non-zero if the block is not consistent. */

u32
affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
{
    __be32 *ptr = (__be32 *)bh->b_data;
    u32 sum;
    int bsize;

    sum = 0;
    for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
        sum += be32_to_cpu(*ptr++);
    return sum;
}

/*
 * Calculate the checksum of a disk block and store it
 * at the indicated position.
 */

void
affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
{
    int cnt = sb->s_blocksize / sizeof(__be32);
    __be32 *ptr = (__be32 *)bh->b_data;
    u32 checksum;
    __be32 *checksumptr;

    checksumptr = ptr + 5;
    *checksumptr = 0;
    for (checksum = 0; cnt > 0; ptr++, cnt--)
        checksum += be32_to_cpu(*ptr);
    *checksumptr = cpu_to_be32(-checksum);
}

void
secs_to_datestamp(time_t secs, struct affs_date *ds)
{
    u32  days;
    u32  minute;

    secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
    if (secs < 0)
        secs = 0;
    days    = secs / 86400;
    secs   -= days * 86400;
    minute  = secs / 60;
    secs   -= minute * 60;

    ds->days = cpu_to_be32(days);
    ds->mins = cpu_to_be32(minute);
    ds->ticks = cpu_to_be32(secs * 50);
}

umode_t
prot_to_mode(u32 prot)
{
    umode_t mode = 0;

    if (!(prot & FIBF_NOWRITE))
        mode |= S_IWUSR;
    if (!(prot & FIBF_NOREAD))
        mode |= S_IRUSR;
    if (!(prot & FIBF_NOEXECUTE))
        mode |= S_IXUSR;
    if (prot & FIBF_GRP_WRITE)
        mode |= S_IWGRP;
    if (prot & FIBF_GRP_READ)
        mode |= S_IRGRP;
    if (prot & FIBF_GRP_EXECUTE)
        mode |= S_IXGRP;
    if (prot & FIBF_OTR_WRITE)
        mode |= S_IWOTH;
    if (prot & FIBF_OTR_READ)
        mode |= S_IROTH;
    if (prot & FIBF_OTR_EXECUTE)
        mode |= S_IXOTH;

    return mode;
}

void
mode_to_prot(struct inode *inode)
{
    u32 prot = AFFS_I(inode)->i_protect;
    umode_t mode = inode->i_mode;

    if (!(mode & S_IXUSR))
        prot |= FIBF_NOEXECUTE;
    if (!(mode & S_IRUSR))
        prot |= FIBF_NOREAD;
    if (!(mode & S_IWUSR))
        prot |= FIBF_NOWRITE;
    if (mode & S_IXGRP)
        prot |= FIBF_GRP_EXECUTE;
    if (mode & S_IRGRP)
        prot |= FIBF_GRP_READ;
    if (mode & S_IWGRP)
        prot |= FIBF_GRP_WRITE;
    if (mode & S_IXOTH)
        prot |= FIBF_OTR_EXECUTE;
    if (mode & S_IROTH)
        prot |= FIBF_OTR_READ;
    if (mode & S_IWOTH)
        prot |= FIBF_OTR_WRITE;

    AFFS_I(inode)->i_protect = prot;
}

void
affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
{
    va_list  args;

    va_start(args,fmt);
    vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
    va_end(args);

    printk(KERN_CRIT "AFFS error (device %s): %s(): %s\n", sb->s_id,
        function,ErrorBuffer);
    if (!(sb->s_flags & MS_RDONLY))
        printk(KERN_WARNING "AFFS: Remounting filesystem read-only\n");
    sb->s_flags |= MS_RDONLY;
}

void
affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
{
    va_list  args;

    va_start(args,fmt);
    vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
    va_end(args);

    printk(KERN_WARNING "AFFS warning (device %s): %s(): %s\n", sb->s_id,
        function,ErrorBuffer);
}

/* Check if the name is valid for a affs object. */

int
affs_check_name(const unsigned char *name, int len)
{
    int  i;

    if (len > 30)
#ifdef AFFS_NO_TRUNCATE
        return -ENAMETOOLONG;
#else
        len = 30;
#endif

    for (i = 0; i < len; i++) {
        if (name[i] < ' ' || name[i] == ':'
            || (name[i] > 0x7e && name[i] < 0xa0))
            return -EINVAL;
    }

    return 0;
}

/* This function copies name to bstr, with at most 30
 * characters length. The bstr will be prepended by
 * a length byte.
 * NOTE: The name will must be already checked by
 *       affs_check_name()!
 */

int
affs_copy_name(unsigned char *bstr, struct dentry *dentry)
{
    int len = min(dentry->d_name.len, 30u);

    *bstr++ = len;
    memcpy(bstr, dentry->d_name.name, len);
    return len;
}