audit: complex interfield comparison helper

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / affs / super.c

/*
 *  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 "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, int clean)
{
        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);

        tail->bm_flag = cpu_to_be32(clean);
        secs_to_datestamp(get_seconds(), &tail->disk_change);
        affs_fix_checksum(sb, 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");

        if (!(sb->s_flags & MS_RDONLY) && sb->s_dirt)
                affs_commit_super(sb, 1, 1);

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

static void
affs_write_super(struct super_block *sb)
{
        lock_super(sb);
        if (!(sb->s_flags & MS_RDONLY))
                affs_commit_super(sb, 1, 2);
        sb->s_dirt = 0;
        unlock_super(sb);

        pr_debug("AFFS: write_super() at %lu, clean=2\n", get_seconds());
}

static int
affs_sync_fs(struct super_block *sb, int wait)
{
        lock_super(sb);
        affs_commit_super(sb, wait, 2);
        sb->s_dirt = 0;
        unlock_super(sb);
        return 0;
}

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)
{
        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,
        .write_super    = affs_write_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, uid_t *uid, gid_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 = option;
                        *mount_opts |= SF_SETGID;
                        break;
                case Opt_setuid:
                        if (match_int(&args[0], &option))
                                return 0;
                        *uid = option;
                        *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;
        uid_t                    uid;
        gid_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;
        mutex_init(&sbi->s_bmlock);
        spin_lock_init(&sbi->symlink_lock);

        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_noinode;
        }

        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_alloc_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:
        if (root_inode)
                iput(root_inode);
out_error_noinode:
        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;
        uid_t                    uid;
        gid_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;
        }

        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_write_super(sb);
                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)