![Jan Kara](/assets/img/avatar_default.png)
When a file is stored in ICB (inode), we overwrite part of the file, and
the page containing file's data is not in page cache, we end up corrupting
file's data by overwriting them with zeros. The problem is we use
simple_write_begin() which simply zeroes parts of the page which are not
written to. The problem has been introduced by be021ee4
(udf: convert to
new aops).
Fix the problem by providing a ->write_begin function which makes the page
properly uptodate.
CC: <stable@vger.kernel.org> # >= 2.6.24
Reported-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Jan Kara <jack@suse.cz>
273 lines
6.7 KiB
C
273 lines
6.7 KiB
C
/*
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* file.c
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*
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* PURPOSE
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* File handling routines for the OSTA-UDF(tm) filesystem.
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*
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* COPYRIGHT
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* This file is distributed under the terms of the GNU General Public
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* License (GPL). Copies of the GPL can be obtained from:
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* ftp://prep.ai.mit.edu/pub/gnu/GPL
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* Each contributing author retains all rights to their own work.
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*
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* (C) 1998-1999 Dave Boynton
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* (C) 1998-2004 Ben Fennema
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* (C) 1999-2000 Stelias Computing Inc
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*
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* HISTORY
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*
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* 10/02/98 dgb Attempt to integrate into udf.o
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* 10/07/98 Switched to using generic_readpage, etc., like isofs
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* And it works!
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* 12/06/98 blf Added udf_file_read. uses generic_file_read for all cases but
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* ICBTAG_FLAG_AD_IN_ICB.
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* 04/06/99 64 bit file handling on 32 bit systems taken from ext2 file.c
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* 05/12/99 Preliminary file write support
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*/
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#include "udfdecl.h"
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#include <linux/fs.h>
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#include <asm/uaccess.h>
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#include <linux/kernel.h>
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#include <linux/string.h> /* memset */
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#include <linux/capability.h>
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#include <linux/errno.h>
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#include <linux/pagemap.h>
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#include <linux/buffer_head.h>
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#include <linux/aio.h>
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#include "udf_i.h"
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#include "udf_sb.h"
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static void __udf_adinicb_readpage(struct page *page)
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{
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struct inode *inode = page->mapping->host;
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char *kaddr;
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struct udf_inode_info *iinfo = UDF_I(inode);
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kaddr = kmap(page);
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memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, inode->i_size);
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memset(kaddr + inode->i_size, 0, PAGE_CACHE_SIZE - inode->i_size);
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flush_dcache_page(page);
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SetPageUptodate(page);
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kunmap(page);
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}
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static int udf_adinicb_readpage(struct file *file, struct page *page)
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{
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BUG_ON(!PageLocked(page));
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__udf_adinicb_readpage(page);
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unlock_page(page);
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return 0;
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}
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static int udf_adinicb_writepage(struct page *page,
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struct writeback_control *wbc)
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{
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struct inode *inode = page->mapping->host;
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char *kaddr;
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struct udf_inode_info *iinfo = UDF_I(inode);
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BUG_ON(!PageLocked(page));
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kaddr = kmap(page);
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memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);
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mark_inode_dirty(inode);
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SetPageUptodate(page);
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kunmap(page);
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unlock_page(page);
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return 0;
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}
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static int udf_adinicb_write_begin(struct file *file,
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struct address_space *mapping, loff_t pos,
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unsigned len, unsigned flags, struct page **pagep,
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void **fsdata)
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{
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struct page *page;
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if (WARN_ON_ONCE(pos >= PAGE_CACHE_SIZE))
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return -EIO;
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page = grab_cache_page_write_begin(mapping, 0, flags);
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if (!page)
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return -ENOMEM;
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*pagep = page;
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if (!PageUptodate(page) && len != PAGE_CACHE_SIZE)
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__udf_adinicb_readpage(page);
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return 0;
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}
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static int udf_adinicb_write_end(struct file *file,
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struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata)
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{
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struct inode *inode = mapping->host;
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unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
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char *kaddr;
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struct udf_inode_info *iinfo = UDF_I(inode);
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kaddr = kmap_atomic(page);
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memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr + offset,
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kaddr + offset, copied);
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kunmap_atomic(kaddr);
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return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
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}
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const struct address_space_operations udf_adinicb_aops = {
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.readpage = udf_adinicb_readpage,
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.writepage = udf_adinicb_writepage,
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.write_begin = udf_adinicb_write_begin,
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.write_end = udf_adinicb_write_end,
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};
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static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t ppos)
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{
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ssize_t retval;
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struct file *file = iocb->ki_filp;
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struct inode *inode = file->f_path.dentry->d_inode;
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int err, pos;
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size_t count = iocb->ki_left;
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struct udf_inode_info *iinfo = UDF_I(inode);
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down_write(&iinfo->i_data_sem);
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if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
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if (file->f_flags & O_APPEND)
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pos = inode->i_size;
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else
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pos = ppos;
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if (inode->i_sb->s_blocksize <
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(udf_file_entry_alloc_offset(inode) +
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pos + count)) {
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err = udf_expand_file_adinicb(inode);
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if (err) {
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udf_debug("udf_expand_adinicb: err=%d\n", err);
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return err;
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}
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} else {
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if (pos + count > inode->i_size)
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iinfo->i_lenAlloc = pos + count;
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else
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iinfo->i_lenAlloc = inode->i_size;
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up_write(&iinfo->i_data_sem);
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}
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} else
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up_write(&iinfo->i_data_sem);
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retval = generic_file_aio_write(iocb, iov, nr_segs, ppos);
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if (retval > 0)
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mark_inode_dirty(inode);
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return retval;
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}
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long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
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{
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struct inode *inode = filp->f_dentry->d_inode;
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long old_block, new_block;
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int result = -EINVAL;
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if (inode_permission(inode, MAY_READ) != 0) {
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udf_debug("no permission to access inode %lu\n", inode->i_ino);
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result = -EPERM;
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goto out;
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}
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if (!arg) {
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udf_debug("invalid argument to udf_ioctl\n");
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result = -EINVAL;
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goto out;
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}
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switch (cmd) {
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case UDF_GETVOLIDENT:
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if (copy_to_user((char __user *)arg,
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UDF_SB(inode->i_sb)->s_volume_ident, 32))
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result = -EFAULT;
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else
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result = 0;
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goto out;
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case UDF_RELOCATE_BLOCKS:
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if (!capable(CAP_SYS_ADMIN)) {
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result = -EACCES;
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goto out;
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}
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if (get_user(old_block, (long __user *)arg)) {
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result = -EFAULT;
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goto out;
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}
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result = udf_relocate_blocks(inode->i_sb,
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old_block, &new_block);
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if (result == 0)
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result = put_user(new_block, (long __user *)arg);
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goto out;
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case UDF_GETEASIZE:
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result = put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
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goto out;
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case UDF_GETEABLOCK:
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result = copy_to_user((char __user *)arg,
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UDF_I(inode)->i_ext.i_data,
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UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
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goto out;
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}
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out:
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return result;
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}
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static int udf_release_file(struct inode *inode, struct file *filp)
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{
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if (filp->f_mode & FMODE_WRITE) {
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down_write(&UDF_I(inode)->i_data_sem);
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udf_discard_prealloc(inode);
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udf_truncate_tail_extent(inode);
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up_write(&UDF_I(inode)->i_data_sem);
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}
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return 0;
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}
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const struct file_operations udf_file_operations = {
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.read = do_sync_read,
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.aio_read = generic_file_aio_read,
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.unlocked_ioctl = udf_ioctl,
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.open = generic_file_open,
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.mmap = generic_file_mmap,
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.write = do_sync_write,
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.aio_write = udf_file_aio_write,
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.release = udf_release_file,
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.fsync = generic_file_fsync,
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.splice_read = generic_file_splice_read,
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.llseek = generic_file_llseek,
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};
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static int udf_setattr(struct dentry *dentry, struct iattr *attr)
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{
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struct inode *inode = dentry->d_inode;
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int error;
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error = inode_change_ok(inode, attr);
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if (error)
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return error;
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if ((attr->ia_valid & ATTR_SIZE) &&
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attr->ia_size != i_size_read(inode)) {
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error = udf_setsize(inode, attr->ia_size);
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if (error)
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return error;
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}
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setattr_copy(inode, attr);
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mark_inode_dirty(inode);
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return 0;
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}
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const struct inode_operations udf_file_inode_operations = {
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.setattr = udf_setattr,
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};
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