file.c

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/*
 * file.c
 *
 * PURPOSE
 *  File handling routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *  This file is distributed under the terms of the GNU General Public
 *  License (GPL). Copies of the GPL can be obtained from:
 *    ftp://prep.ai.mit.edu/pub/gnu/GPL
 *  Each contributing author retains all rights to their own work.
 *
 *  (C) 1998-1999 Dave Boynton
 *  (C) 1998-2004 Ben Fennema
 *  (C) 1999-2000 Stelias Computing Inc
 *
 * HISTORY
 *
 *  10/02/98 dgb  Attempt to integrate into udf.o
 *  10/07/98      Switched to using generic_readpage, etc., like isofs
 *                And it works!
 *  12/06/98 blf  Added udf_file_read. uses generic_file_read for all cases but
 *                ICBTAG_FLAG_AD_IN_ICB.
 *  04/06/99      64 bit file handling on 32 bit systems taken from ext2 file.c
 *  05/12/99      Preliminary file write support
 */

#include "udfdecl.h"
#include <linux/fs.h>
#include <asm/uaccess.h>
#include <linux/kernel.h>
#include <linux/string.h> /* memset */
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include <linux/aio.h>

#include "udf_i.h"
#include "udf_sb.h"

static void __udf_adinicb_readpage(struct page *page)
{
    struct inode *inode = page->mapping->host;
    char *kaddr;
    struct udf_inode_info *iinfo = UDF_I(inode);

    kaddr = kmap(page);
    memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, inode->i_size);
    memset(kaddr + inode->i_size, 0, PAGE_CACHE_SIZE - inode->i_size);
    flush_dcache_page(page);
    SetPageUptodate(page);
    kunmap(page);
}

static int udf_adinicb_readpage(struct file *file, struct page *page)
{
    BUG_ON(!PageLocked(page));
    __udf_adinicb_readpage(page);
    unlock_page(page);

    return 0;
}

static int udf_adinicb_writepage(struct page *page,
                 struct writeback_control *wbc)
{
    struct inode *inode = page->mapping->host;
    char *kaddr;
    struct udf_inode_info *iinfo = UDF_I(inode);

    BUG_ON(!PageLocked(page));

    kaddr = kmap(page);
    memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);
    mark_inode_dirty(inode);
    SetPageUptodate(page);
    kunmap(page);
    unlock_page(page);

    return 0;
}

static int udf_adinicb_write_begin(struct file *file,
            struct address_space *mapping, loff_t pos,
            unsigned len, unsigned flags, struct page **pagep,
            void **fsdata)
{
    struct page *page;

    if (WARN_ON_ONCE(pos >= PAGE_CACHE_SIZE))
        return -EIO;
    page = grab_cache_page_write_begin(mapping, 0, flags);
    if (!page)
        return -ENOMEM;
    *pagep = page;

    if (!PageUptodate(page) && len != PAGE_CACHE_SIZE)
        __udf_adinicb_readpage(page);
    return 0;
}

static int udf_adinicb_write_end(struct file *file,
            struct address_space *mapping,
            loff_t pos, unsigned len, unsigned copied,
            struct page *page, void *fsdata)
{
    struct inode *inode = mapping->host;
    unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
    char *kaddr;
    struct udf_inode_info *iinfo = UDF_I(inode);

    kaddr = kmap_atomic(page);
    memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr + offset,
        kaddr + offset, copied);
    kunmap_atomic(kaddr);

    return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
}

static ssize_t udf_adinicb_direct_IO(int rw, struct kiocb *iocb,
                     const struct iovec *iov,
                     loff_t offset, unsigned long nr_segs)
{
    /* Fallback to buffered I/O. */
    return 0;
}

const struct address_space_operations udf_adinicb_aops = {
    .readpage   = udf_adinicb_readpage,
    .writepage  = udf_adinicb_writepage,
    .write_begin    = udf_adinicb_write_begin,
    .write_end  = udf_adinicb_write_end,
    .direct_IO  = udf_adinicb_direct_IO,
};

static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                  unsigned long nr_segs, loff_t ppos)
{
    ssize_t retval;
    struct file *file = iocb->ki_filp;
    struct inode *inode = file->f_path.dentry->d_inode;
    int err, pos;
    size_t count = iocb->ki_left;
    struct udf_inode_info *iinfo = UDF_I(inode);

    down_write(&iinfo->i_data_sem);
    if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
        if (file->f_flags & O_APPEND)
            pos = inode->i_size;
        else
            pos = ppos;

        if (inode->i_sb->s_blocksize <
                (udf_file_entry_alloc_offset(inode) +
                        pos + count)) {
            err = udf_expand_file_adinicb(inode);
            if (err) {
                udf_debug("udf_expand_adinicb: err=%d\n", err);
                return err;
            }
        } else {
            if (pos + count > inode->i_size)
                iinfo->i_lenAlloc = pos + count;
            else
                iinfo->i_lenAlloc = inode->i_size;
            up_write(&iinfo->i_data_sem);
        }
    } else
        up_write(&iinfo->i_data_sem);

    retval = generic_file_aio_write(iocb, iov, nr_segs, ppos);
    if (retval > 0)
        mark_inode_dirty(inode);

    return retval;
}

long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
    struct inode *inode = filp->f_dentry->d_inode;
    long old_block, new_block;
    int result = -EINVAL;

    if (inode_permission(inode, MAY_READ) != 0) {
        udf_debug("no permission to access inode %lu\n", inode->i_ino);
        result = -EPERM;
        goto out;
    }

    if (!arg) {
        udf_debug("invalid argument to udf_ioctl\n");
        result = -EINVAL;
        goto out;
    }

    switch (cmd) {
    case UDF_GETVOLIDENT:
        if (copy_to_user((char __user *)arg,
                 UDF_SB(inode->i_sb)->s_volume_ident, 32))
            result = -EFAULT;
        else
            result = 0;
        goto out;
    case UDF_RELOCATE_BLOCKS:
        if (!capable(CAP_SYS_ADMIN)) {
            result = -EACCES;
            goto out;
        }
        if (get_user(old_block, (long __user *)arg)) {
            result = -EFAULT;
            goto out;
        }
        result = udf_relocate_blocks(inode->i_sb,
                        old_block, &new_block);
        if (result == 0)
            result = put_user(new_block, (long __user *)arg);
        goto out;
    case UDF_GETEASIZE:
        result = put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
        goto out;
    case UDF_GETEABLOCK:
        result = copy_to_user((char __user *)arg,
                      UDF_I(inode)->i_ext.i_data,
                      UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
        goto out;
    }

out:
    return result;
}

static int udf_release_file(struct inode *inode, struct file *filp)
{
    if (filp->f_mode & FMODE_WRITE) {
        down_write(&UDF_I(inode)->i_data_sem);
        udf_discard_prealloc(inode);
        udf_truncate_tail_extent(inode);
        up_write(&UDF_I(inode)->i_data_sem);
    }
    return 0;
}

const struct file_operations udf_file_operations = {
    .read           = do_sync_read,
    .aio_read       = generic_file_aio_read,
    .unlocked_ioctl     = udf_ioctl,
    .open           = generic_file_open,
    .mmap           = generic_file_mmap,
    .write          = do_sync_write,
    .aio_write      = udf_file_aio_write,
    .release        = udf_release_file,
    .fsync          = generic_file_fsync,
    .splice_read        = generic_file_splice_read,
    .llseek         = generic_file_llseek,
};

static int udf_setattr(struct dentry *dentry, struct iattr *attr)
{
    struct inode *inode = dentry->d_inode;
    int error;

    error = inode_change_ok(inode, attr);
    if (error)
        return error;

    if ((attr->ia_valid & ATTR_SIZE) &&
        attr->ia_size != i_size_read(inode)) {
        error = udf_setsize(inode, attr->ia_size);
        if (error)
            return error;
    }

    setattr_copy(inode, attr);
    mark_inode_dirty(inode);
    return 0;
}

const struct inode_operations udf_file_inode_operations = {
    .setattr        = udf_setattr,
};