super.c

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/*
 *  linux/fs/affs/inode.c
 *
 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
 *
 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
 *
 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
 *
 *  (C) 1991  Linus Torvalds - minix filesystem
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/statfs.h>
#include <linux/parser.h>
#include <linux/magic.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/writeback.h>
#include "affs.h"

extern struct timezone sys_tz;

static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
static int affs_remount (struct super_block *sb, int *flags, char *data);

static void
affs_commit_super(struct super_block *sb, int wait)
{
    struct affs_sb_info *sbi = AFFS_SB(sb);
    struct buffer_head *bh = sbi->s_root_bh;
    struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);

    lock_buffer(bh);
    secs_to_datestamp(get_seconds(), &tail->disk_change);
    affs_fix_checksum(sb, bh);
    unlock_buffer(bh);

    mark_buffer_dirty(bh);
    if (wait)
        sync_dirty_buffer(bh);
}

static void
affs_put_super(struct super_block *sb)
{
    struct affs_sb_info *sbi = AFFS_SB(sb);
    pr_debug("AFFS: put_super()\n");

    cancel_delayed_work_sync(&sbi->sb_work);
    kfree(sbi->s_prefix);
    affs_free_bitmap(sb);
    affs_brelse(sbi->s_root_bh);
    kfree(sbi);
    sb->s_fs_info = NULL;
}

static int
affs_sync_fs(struct super_block *sb, int wait)
{
    affs_commit_super(sb, wait);
    return 0;
}

static void flush_superblock(struct work_struct *work)
{
    struct affs_sb_info *sbi;
    struct super_block *sb;

    sbi = container_of(work, struct affs_sb_info, sb_work.work);
    sb = sbi->sb;

    spin_lock(&sbi->work_lock);
    sbi->work_queued = 0;
    spin_unlock(&sbi->work_lock);

    affs_commit_super(sb, 1);
}

void affs_mark_sb_dirty(struct super_block *sb)
{
    struct affs_sb_info *sbi = AFFS_SB(sb);
    unsigned long delay;

    if (sb->s_flags & MS_RDONLY)
           return;

    spin_lock(&sbi->work_lock);
    if (!sbi->work_queued) {
           delay = msecs_to_jiffies(dirty_writeback_interval * 10);
           queue_delayed_work(system_long_wq, &sbi->sb_work, delay);
           sbi->work_queued = 1;
    }
    spin_unlock(&sbi->work_lock);
}

static struct kmem_cache * affs_inode_cachep;

static struct inode *affs_alloc_inode(struct super_block *sb)
{
    struct affs_inode_info *i;

    i = kmem_cache_alloc(affs_inode_cachep, GFP_KERNEL);
    if (!i)
        return NULL;

    i->vfs_inode.i_version = 1;
    i->i_lc = NULL;
    i->i_ext_bh = NULL;
    i->i_pa_cnt = 0;

    return &i->vfs_inode;
}

static void affs_i_callback(struct rcu_head *head)
{
    struct inode *inode = container_of(head, struct inode, i_rcu);
    kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
}

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

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

    sema_init(&ei->i_link_lock, 1);
    sema_init(&ei->i_ext_lock, 1);
    inode_init_once(&ei->vfs_inode);
}

static int init_inodecache(void)
{
    affs_inode_cachep = kmem_cache_create("affs_inode_cache",
                         sizeof(struct affs_inode_info),
                         0, (SLAB_RECLAIM_ACCOUNT|
                        SLAB_MEM_SPREAD),
                         init_once);
    if (affs_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(affs_inode_cachep);
}

static const struct super_operations affs_sops = {
    .alloc_inode    = affs_alloc_inode,
    .destroy_inode  = affs_destroy_inode,
    .write_inode    = affs_write_inode,
    .evict_inode    = affs_evict_inode,
    .put_super  = affs_put_super,
    .sync_fs    = affs_sync_fs,
    .statfs     = affs_statfs,
    .remount_fs = affs_remount,
    .show_options   = generic_show_options,
};

enum {
    Opt_bs, Opt_mode, Opt_mufs, Opt_prefix, Opt_protect,
    Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
    Opt_verbose, Opt_volume, Opt_ignore, Opt_err,
};

static const match_table_t tokens = {
    {Opt_bs, "bs=%u"},
    {Opt_mode, "mode=%o"},
    {Opt_mufs, "mufs"},
    {Opt_prefix, "prefix=%s"},
    {Opt_protect, "protect"},
    {Opt_reserved, "reserved=%u"},
    {Opt_root, "root=%u"},
    {Opt_setgid, "setgid=%u"},
    {Opt_setuid, "setuid=%u"},
    {Opt_verbose, "verbose"},
    {Opt_volume, "volume=%s"},
    {Opt_ignore, "grpquota"},
    {Opt_ignore, "noquota"},
    {Opt_ignore, "quota"},
    {Opt_ignore, "usrquota"},
    {Opt_err, NULL},
};

static int
parse_options(char *options, kuid_t *uid, kgid_t *gid, int *mode, int *reserved, s32 *root,
        int *blocksize, char **prefix, char *volume, unsigned long *mount_opts)
{
    char *p;
    substring_t args[MAX_OPT_ARGS];

    /* Fill in defaults */

    *uid        = current_uid();
    *gid        = current_gid();
    *reserved   = 2;
    *root       = -1;
    *blocksize  = -1;
    volume[0]   = ':';
    volume[1]   = 0;
    *mount_opts = 0;
    if (!options)
        return 1;

    while ((p = strsep(&options, ",")) != NULL) {
        int token, n, option;
        if (!*p)
            continue;

        token = match_token(p, tokens, args);
        switch (token) {
        case Opt_bs:
            if (match_int(&args[0], &n))
                return 0;
            if (n != 512 && n != 1024 && n != 2048
                && n != 4096) {
                printk ("AFFS: Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
                return 0;
            }
            *blocksize = n;
            break;
        case Opt_mode:
            if (match_octal(&args[0], &option))
                return 0;
            *mode = option & 0777;
            *mount_opts |= SF_SETMODE;
            break;
        case Opt_mufs:
            *mount_opts |= SF_MUFS;
            break;
        case Opt_prefix:
            *prefix = match_strdup(&args[0]);
            if (!*prefix)
                return 0;
            *mount_opts |= SF_PREFIX;
            break;
        case Opt_protect:
            *mount_opts |= SF_IMMUTABLE;
            break;
        case Opt_reserved:
            if (match_int(&args[0], reserved))
                return 0;
            break;
        case Opt_root:
            if (match_int(&args[0], root))
                return 0;
            break;
        case Opt_setgid:
            if (match_int(&args[0], &option))
                return 0;
            *gid = make_kgid(current_user_ns(), option);
            if (!gid_valid(*gid))
                return 0;
            *mount_opts |= SF_SETGID;
            break;
        case Opt_setuid:
            if (match_int(&args[0], &option))
                return 0;
            *uid = make_kuid(current_user_ns(), option);
            if (!uid_valid(*uid))
                return 0;
            *mount_opts |= SF_SETUID;
            break;
        case Opt_verbose:
            *mount_opts |= SF_VERBOSE;
            break;
        case Opt_volume: {
            char *vol = match_strdup(&args[0]);
            if (!vol)
                return 0;
            strlcpy(volume, vol, 32);
            kfree(vol);
            break;
        }
        case Opt_ignore:
            /* Silently ignore the quota options */
            break;
        default:
            printk("AFFS: Unrecognized mount option \"%s\" "
                    "or missing value\n", p);
            return 0;
        }
    }
    return 1;
}

/* This function definitely needs to be split up. Some fine day I'll
 * hopefully have the guts to do so. Until then: sorry for the mess.
 */

static int affs_fill_super(struct super_block *sb, void *data, int silent)
{
    struct affs_sb_info *sbi;
    struct buffer_head  *root_bh = NULL;
    struct buffer_head  *boot_bh;
    struct inode        *root_inode = NULL;
    s32          root_block;
    int          size, blocksize;
    u32          chksum;
    int          num_bm;
    int          i, j;
    s32          key;
    kuid_t           uid;
    kgid_t           gid;
    int          reserved;
    unsigned long        mount_flags;
    int          tmp_flags; /* fix remount prototype... */
    u8           sig[4];
    int          ret = -EINVAL;

    save_mount_options(sb, data);

    pr_debug("AFFS: read_super(%s)\n",data ? (const char *)data : "no options");

    sb->s_magic             = AFFS_SUPER_MAGIC;
    sb->s_op                = &affs_sops;
    sb->s_flags |= MS_NODIRATIME;

    sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
    if (!sbi)
        return -ENOMEM;

    sb->s_fs_info = sbi;
    sbi->sb = sb;
    mutex_init(&sbi->s_bmlock);
    spin_lock_init(&sbi->symlink_lock);
    spin_lock_init(&sbi->work_lock);
    INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);

    if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
                &blocksize,&sbi->s_prefix,
                sbi->s_volume, &mount_flags)) {
        printk(KERN_ERR "AFFS: Error parsing options\n");
        kfree(sbi->s_prefix);
        kfree(sbi);
        return -EINVAL;
    }
    /* N.B. after this point s_prefix must be released */

    sbi->s_flags   = mount_flags;
    sbi->s_mode    = i;
    sbi->s_uid     = uid;
    sbi->s_gid     = gid;
    sbi->s_reserved= reserved;

    /* Get the size of the device in 512-byte blocks.
     * If we later see that the partition uses bigger
     * blocks, we will have to change it.
     */

    size = sb->s_bdev->bd_inode->i_size >> 9;
    pr_debug("AFFS: initial blocksize=%d, #blocks=%d\n", 512, size);

    affs_set_blocksize(sb, PAGE_SIZE);
    /* Try to find root block. Its location depends on the block size. */

    i = 512;
    j = 4096;
    if (blocksize > 0) {
        i = j = blocksize;
        size = size / (blocksize / 512);
    }
    for (blocksize = i, key = 0; blocksize <= j; blocksize <<= 1, size >>= 1) {
        sbi->s_root_block = root_block;
        if (root_block < 0)
            sbi->s_root_block = (reserved + size - 1) / 2;
        pr_debug("AFFS: setting blocksize to %d\n", blocksize);
        affs_set_blocksize(sb, blocksize);
        sbi->s_partition_size = size;

        /* The root block location that was calculated above is not
         * correct if the partition size is an odd number of 512-
         * byte blocks, which will be rounded down to a number of
         * 1024-byte blocks, and if there were an even number of
         * reserved blocks. Ideally, all partition checkers should
         * report the real number of blocks of the real blocksize,
         * but since this just cannot be done, we have to try to
         * find the root block anyways. In the above case, it is one
         * block behind the calculated one. So we check this one, too.
         */
        for (num_bm = 0; num_bm < 2; num_bm++) {
            pr_debug("AFFS: Dev %s, trying root=%u, bs=%d, "
                "size=%d, reserved=%d\n",
                sb->s_id,
                sbi->s_root_block + num_bm,
                blocksize, size, reserved);
            root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
            if (!root_bh)
                continue;
            if (!affs_checksum_block(sb, root_bh) &&
                be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
                be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
                sbi->s_hashsize    = blocksize / 4 - 56;
                sbi->s_root_block += num_bm;
                key                        = 1;
                goto got_root;
            }
            affs_brelse(root_bh);
            root_bh = NULL;
        }
    }
    if (!silent)
        printk(KERN_ERR "AFFS: No valid root block on device %s\n",
            sb->s_id);
    goto out_error;

    /* N.B. after this point bh must be released */
got_root:
    root_block = sbi->s_root_block;

    /* Find out which kind of FS we have */
    boot_bh = sb_bread(sb, 0);
    if (!boot_bh) {
        printk(KERN_ERR "AFFS: Cannot read boot block\n");
        goto out_error;
    }
    memcpy(sig, boot_bh->b_data, 4);
    brelse(boot_bh);
    chksum = be32_to_cpu(*(__be32 *)sig);

    /* Dircache filesystems are compatible with non-dircache ones
     * when reading. As long as they aren't supported, writing is
     * not recommended.
     */
    if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
         || chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
        printk(KERN_NOTICE "AFFS: Dircache FS - mounting %s read only\n",
            sb->s_id);
        sb->s_flags |= MS_RDONLY;
    }
    switch (chksum) {
        case MUFS_FS:
        case MUFS_INTLFFS:
        case MUFS_DCFFS:
            sbi->s_flags |= SF_MUFS;
            /* fall thru */
        case FS_INTLFFS:
        case FS_DCFFS:
            sbi->s_flags |= SF_INTL;
            break;
        case MUFS_FFS:
            sbi->s_flags |= SF_MUFS;
            break;
        case FS_FFS:
            break;
        case MUFS_OFS:
            sbi->s_flags |= SF_MUFS;
            /* fall thru */
        case FS_OFS:
            sbi->s_flags |= SF_OFS;
            sb->s_flags |= MS_NOEXEC;
            break;
        case MUFS_DCOFS:
        case MUFS_INTLOFS:
            sbi->s_flags |= SF_MUFS;
        case FS_DCOFS:
        case FS_INTLOFS:
            sbi->s_flags |= SF_INTL | SF_OFS;
            sb->s_flags |= MS_NOEXEC;
            break;
        default:
            printk(KERN_ERR "AFFS: Unknown filesystem on device %s: %08X\n",
                sb->s_id, chksum);
            goto out_error;
    }

    if (mount_flags & SF_VERBOSE) {
        u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
        printk(KERN_NOTICE "AFFS: Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
            len > 31 ? 31 : len,
            AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
            sig, sig[3] + '0', blocksize);
    }

    sb->s_flags |= MS_NODEV | MS_NOSUID;

    sbi->s_data_blksize = sb->s_blocksize;
    if (sbi->s_flags & SF_OFS)
        sbi->s_data_blksize -= 24;

    /* Keep super block in cache */
    sbi->s_root_bh = root_bh;
    /* N.B. after this point s_root_bh must be released */

    tmp_flags = sb->s_flags;
    if (affs_init_bitmap(sb, &tmp_flags))
        goto out_error;
    sb->s_flags = tmp_flags;

    /* set up enough so that it can read an inode */

    root_inode = affs_iget(sb, root_block);
    if (IS_ERR(root_inode)) {
        ret = PTR_ERR(root_inode);
        goto out_error;
    }

    if (AFFS_SB(sb)->s_flags & SF_INTL)
        sb->s_d_op = &affs_intl_dentry_operations;
    else
        sb->s_d_op = &affs_dentry_operations;

    sb->s_root = d_make_root(root_inode);
    if (!sb->s_root) {
        printk(KERN_ERR "AFFS: Get root inode failed\n");
        goto out_error;
    }

    pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
    return 0;

    /*
     * Begin the cascaded cleanup ...
     */
out_error:
    kfree(sbi->s_bitmap);
    affs_brelse(root_bh);
    kfree(sbi->s_prefix);
    kfree(sbi);
    sb->s_fs_info = NULL;
    return ret;
}

static int
affs_remount(struct super_block *sb, int *flags, char *data)
{
    struct affs_sb_info *sbi = AFFS_SB(sb);
    int          blocksize;
    kuid_t           uid;
    kgid_t           gid;
    int          mode;
    int          reserved;
    int          root_block;
    unsigned long        mount_flags;
    int          res = 0;
    char            *new_opts = kstrdup(data, GFP_KERNEL);
    char             volume[32];
    char            *prefix = NULL;

    pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);

    *flags |= MS_NODIRATIME;

    memcpy(volume, sbi->s_volume, 32);
    if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
               &blocksize, &prefix, volume,
               &mount_flags)) {
        kfree(prefix);
        kfree(new_opts);
        return -EINVAL;
    }

    flush_delayed_work(&sbi->sb_work);
    replace_mount_options(sb, new_opts);

    sbi->s_flags = mount_flags;
    sbi->s_mode  = mode;
    sbi->s_uid   = uid;
    sbi->s_gid   = gid;
    /* protect against readers */
    spin_lock(&sbi->symlink_lock);
    if (prefix) {
        kfree(sbi->s_prefix);
        sbi->s_prefix = prefix;
    }
    memcpy(sbi->s_volume, volume, 32);
    spin_unlock(&sbi->symlink_lock);

    if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
        return 0;

    if (*flags & MS_RDONLY)
        affs_free_bitmap(sb);
    else
        res = affs_init_bitmap(sb, flags);

    return res;
}

static int
affs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
    struct super_block *sb = dentry->d_sb;
    int      free;
    u64      id = huge_encode_dev(sb->s_bdev->bd_dev);

    pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
         AFFS_SB(sb)->s_reserved);

    free          = affs_count_free_blocks(sb);
    buf->f_type    = AFFS_SUPER_MAGIC;
    buf->f_bsize   = sb->s_blocksize;
    buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
    buf->f_bfree   = free;
    buf->f_bavail  = free;
    buf->f_fsid.val[0] = (u32)id;
    buf->f_fsid.val[1] = (u32)(id >> 32);
    buf->f_namelen = 30;
    return 0;
}

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

static struct file_system_type affs_fs_type = {
    .owner      = THIS_MODULE,
    .name       = "affs",
    .mount      = affs_mount,
    .kill_sb    = kill_block_super,
    .fs_flags   = FS_REQUIRES_DEV,
};

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

static void __exit exit_affs_fs(void)
{
    unregister_filesystem(&affs_fs_type);
    destroy_inodecache();
}

MODULE_DESCRIPTION("Amiga filesystem support for Linux");
MODULE_LICENSE("GPL");

module_init(init_affs_fs)
module_exit(exit_affs_fs)