ioctl.c

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/*
 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
 */

#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include "reiserfs.h"
#include <linux/time.h>
#include <asm/uaccess.h>
#include <linux/pagemap.h>
#include <linux/compat.h>

/*
 * reiserfs_ioctl - handler for ioctl for inode
 * supported commands:
 *  1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect
 *                           and prevent packing file (argument arg has to be non-zero)
 *  2) REISERFS_IOC_[GS]ETFLAGS, REISERFS_IOC_[GS]ETVERSION
 *  3) That's all for a while ...
 */
long reiserfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
    struct inode *inode = filp->f_path.dentry->d_inode;
    unsigned int flags;
    int err = 0;

    reiserfs_write_lock(inode->i_sb);

    switch (cmd) {
    case REISERFS_IOC_UNPACK:
        if (S_ISREG(inode->i_mode)) {
            if (arg)
                err = reiserfs_unpack(inode, filp);
        } else
            err = -ENOTTY;
        break;
        /*
         * following two cases are taken from fs/ext2/ioctl.c by Remy
         * Card ([email protected])
         */
    case REISERFS_IOC_GETFLAGS:
        if (!reiserfs_attrs(inode->i_sb)) {
            err = -ENOTTY;
            break;
        }

        flags = REISERFS_I(inode)->i_attrs;
        i_attrs_to_sd_attrs(inode, (__u16 *) & flags);
        err = put_user(flags, (int __user *)arg);
        break;
    case REISERFS_IOC_SETFLAGS:{
            if (!reiserfs_attrs(inode->i_sb)) {
                err = -ENOTTY;
                break;
            }

            err = mnt_want_write_file(filp);
            if (err)
                break;

            if (!inode_owner_or_capable(inode)) {
                err = -EPERM;
                goto setflags_out;
            }
            if (get_user(flags, (int __user *)arg)) {
                err = -EFAULT;
                goto setflags_out;
            }
            /*
             * Is it quota file? Do not allow user to mess with it
             */
            if (IS_NOQUOTA(inode)) {
                err = -EPERM;
                goto setflags_out;
            }
            if (((flags ^ REISERFS_I(inode)->
                  i_attrs) & (REISERFS_IMMUTABLE_FL |
                      REISERFS_APPEND_FL))
                && !capable(CAP_LINUX_IMMUTABLE)) {
                err = -EPERM;
                goto setflags_out;
            }
            if ((flags & REISERFS_NOTAIL_FL) &&
                S_ISREG(inode->i_mode)) {
                int result;

                result = reiserfs_unpack(inode, filp);
                if (result) {
                    err = result;
                    goto setflags_out;
                }
            }
            sd_attrs_to_i_attrs(flags, inode);
            REISERFS_I(inode)->i_attrs = flags;
            inode->i_ctime = CURRENT_TIME_SEC;
            mark_inode_dirty(inode);
setflags_out:
            mnt_drop_write_file(filp);
            break;
        }
    case REISERFS_IOC_GETVERSION:
        err = put_user(inode->i_generation, (int __user *)arg);
        break;
    case REISERFS_IOC_SETVERSION:
        if (!inode_owner_or_capable(inode)) {
            err = -EPERM;
            break;
        }
        err = mnt_want_write_file(filp);
        if (err)
            break;
        if (get_user(inode->i_generation, (int __user *)arg)) {
            err = -EFAULT;
            goto setversion_out;
        }
        inode->i_ctime = CURRENT_TIME_SEC;
        mark_inode_dirty(inode);
setversion_out:
        mnt_drop_write_file(filp);
        break;
    default:
        err = -ENOTTY;
    }

    reiserfs_write_unlock(inode->i_sb);

    return err;
}

#ifdef CONFIG_COMPAT
long reiserfs_compat_ioctl(struct file *file, unsigned int cmd,
                unsigned long arg)
{
    /* These are just misnamed, they actually get/put from/to user an int */
    switch (cmd) {
    case REISERFS_IOC32_UNPACK:
        cmd = REISERFS_IOC_UNPACK;
        break;
    case REISERFS_IOC32_GETFLAGS:
        cmd = REISERFS_IOC_GETFLAGS;
        break;
    case REISERFS_IOC32_SETFLAGS:
        cmd = REISERFS_IOC_SETFLAGS;
        break;
    case REISERFS_IOC32_GETVERSION:
        cmd = REISERFS_IOC_GETVERSION;
        break;
    case REISERFS_IOC32_SETVERSION:
        cmd = REISERFS_IOC_SETVERSION;
        break;
    default:
        return -ENOIOCTLCMD;
    }

    return reiserfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
}
#endif

int reiserfs_commit_write(struct file *f, struct page *page,
              unsigned from, unsigned to);
/*
** reiserfs_unpack
** Function try to convert tail from direct item into indirect.
** It set up nopack attribute in the REISERFS_I(inode)->nopack
*/
int reiserfs_unpack(struct inode *inode, struct file *filp)
{
    int retval = 0;
    int depth;
    int index;
    struct page *page;
    struct address_space *mapping;
    unsigned long write_from;
    unsigned long blocksize = inode->i_sb->s_blocksize;

    if (inode->i_size == 0) {
        REISERFS_I(inode)->i_flags |= i_nopack_mask;
        return 0;
    }
    /* ioctl already done */
    if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
        return 0;
    }

    depth = reiserfs_write_lock_once(inode->i_sb);

    /* we need to make sure nobody is changing the file size beneath us */
    reiserfs_mutex_lock_safe(&inode->i_mutex, inode->i_sb);

    write_from = inode->i_size & (blocksize - 1);
    /* if we are on a block boundary, we are already unpacked.  */
    if (write_from == 0) {
        REISERFS_I(inode)->i_flags |= i_nopack_mask;
        goto out;
    }

    /* we unpack by finding the page with the tail, and calling
     ** __reiserfs_write_begin on that page.  This will force a
     ** reiserfs_get_block to unpack the tail for us.
     */
    index = inode->i_size >> PAGE_CACHE_SHIFT;
    mapping = inode->i_mapping;
    page = grab_cache_page(mapping, index);
    retval = -ENOMEM;
    if (!page) {
        goto out;
    }
    retval = __reiserfs_write_begin(page, write_from, 0);
    if (retval)
        goto out_unlock;

    /* conversion can change page contents, must flush */
    flush_dcache_page(page);
    retval = reiserfs_commit_write(NULL, page, write_from, write_from);
    REISERFS_I(inode)->i_flags |= i_nopack_mask;

      out_unlock:
    unlock_page(page);
    page_cache_release(page);

      out:
    mutex_unlock(&inode->i_mutex);
    reiserfs_write_unlock_once(inode->i_sb, depth);
    return retval;
}