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![Christoph Hellwig](/assets/img/avatar_default.png)
To allow various options to work per-mount instead of per-sb we need a struct vfsmount when updating ctime and mtime. This preparation patch replaces the inode_update_time routine with a file_update_atime routine so we can easily get at the vfsmount. (and the file makes more sense in this context anyway). Also get rid of the unused second argument - we always want to update the ctime when calling this routine. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Anton Altaparmakov <aia21@cantab.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
442 lines
10 KiB
C
442 lines
10 KiB
C
/*
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* linux/mm/filemap_xip.c
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*
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* Copyright (C) 2005 IBM Corporation
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* Author: Carsten Otte <cotte@de.ibm.com>
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*
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* derived from linux/mm/filemap.c - Copyright (C) Linus Torvalds
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*
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*/
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/module.h>
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#include <linux/uio.h>
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#include <linux/rmap.h>
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#include <asm/tlbflush.h>
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#include "filemap.h"
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/*
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* This is a file read routine for execute in place files, and uses
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* the mapping->a_ops->get_xip_page() function for the actual low-level
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* stuff.
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*
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* Note the struct file* is not used at all. It may be NULL.
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*/
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static void
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do_xip_mapping_read(struct address_space *mapping,
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struct file_ra_state *_ra,
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struct file *filp,
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loff_t *ppos,
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read_descriptor_t *desc,
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read_actor_t actor)
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{
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struct inode *inode = mapping->host;
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unsigned long index, end_index, offset;
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loff_t isize;
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BUG_ON(!mapping->a_ops->get_xip_page);
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index = *ppos >> PAGE_CACHE_SHIFT;
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offset = *ppos & ~PAGE_CACHE_MASK;
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isize = i_size_read(inode);
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if (!isize)
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goto out;
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end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
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for (;;) {
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struct page *page;
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unsigned long nr, ret;
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/* nr is the maximum number of bytes to copy from this page */
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nr = PAGE_CACHE_SIZE;
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if (index >= end_index) {
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if (index > end_index)
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goto out;
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nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
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if (nr <= offset) {
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goto out;
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}
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}
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nr = nr - offset;
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page = mapping->a_ops->get_xip_page(mapping,
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index*(PAGE_SIZE/512), 0);
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if (!page)
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goto no_xip_page;
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if (unlikely(IS_ERR(page))) {
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if (PTR_ERR(page) == -ENODATA) {
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/* sparse */
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page = ZERO_PAGE(0);
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} else {
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desc->error = PTR_ERR(page);
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goto out;
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}
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}
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/* If users can be writing to this page using arbitrary
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* virtual addresses, take care about potential aliasing
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* before reading the page on the kernel side.
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*/
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if (mapping_writably_mapped(mapping))
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flush_dcache_page(page);
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/*
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* Ok, we have the page, so now we can copy it to user space...
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*
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* The actor routine returns how many bytes were actually used..
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* NOTE! This may not be the same as how much of a user buffer
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* we filled up (we may be padding etc), so we can only update
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* "pos" here (the actor routine has to update the user buffer
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* pointers and the remaining count).
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*/
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ret = actor(desc, page, offset, nr);
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offset += ret;
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index += offset >> PAGE_CACHE_SHIFT;
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offset &= ~PAGE_CACHE_MASK;
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if (ret == nr && desc->count)
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continue;
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goto out;
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no_xip_page:
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/* Did not get the page. Report it */
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desc->error = -EIO;
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goto out;
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}
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out:
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*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
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if (filp)
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file_accessed(filp);
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}
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ssize_t
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xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
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{
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read_descriptor_t desc;
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if (!access_ok(VERIFY_WRITE, buf, len))
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return -EFAULT;
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desc.written = 0;
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desc.arg.buf = buf;
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desc.count = len;
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desc.error = 0;
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do_xip_mapping_read(filp->f_mapping, &filp->f_ra, filp,
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ppos, &desc, file_read_actor);
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if (desc.written)
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return desc.written;
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else
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return desc.error;
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}
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EXPORT_SYMBOL_GPL(xip_file_read);
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ssize_t
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xip_file_sendfile(struct file *in_file, loff_t *ppos,
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size_t count, read_actor_t actor, void *target)
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{
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read_descriptor_t desc;
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if (!count)
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return 0;
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desc.written = 0;
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desc.count = count;
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desc.arg.data = target;
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desc.error = 0;
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do_xip_mapping_read(in_file->f_mapping, &in_file->f_ra, in_file,
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ppos, &desc, actor);
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if (desc.written)
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return desc.written;
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return desc.error;
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}
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EXPORT_SYMBOL_GPL(xip_file_sendfile);
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/*
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* __xip_unmap is invoked from xip_unmap and
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* xip_write
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*
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* This function walks all vmas of the address_space and unmaps the
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* ZERO_PAGE when found at pgoff. Should it go in rmap.c?
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*/
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static void
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__xip_unmap (struct address_space * mapping,
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unsigned long pgoff)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm;
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struct prio_tree_iter iter;
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unsigned long address;
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pte_t *pte;
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pte_t pteval;
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spinlock_t *ptl;
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struct page *page;
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spin_lock(&mapping->i_mmap_lock);
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vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
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mm = vma->vm_mm;
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address = vma->vm_start +
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((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
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BUG_ON(address < vma->vm_start || address >= vma->vm_end);
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page = ZERO_PAGE(address);
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pte = page_check_address(page, mm, address, &ptl);
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if (pte) {
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/* Nuke the page table entry. */
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flush_cache_page(vma, address, pte_pfn(*pte));
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pteval = ptep_clear_flush(vma, address, pte);
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page_remove_rmap(page);
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dec_mm_counter(mm, file_rss);
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BUG_ON(pte_dirty(pteval));
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pte_unmap_unlock(pte, ptl);
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page_cache_release(page);
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}
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}
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spin_unlock(&mapping->i_mmap_lock);
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}
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/*
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* xip_nopage() is invoked via the vma operations vector for a
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* mapped memory region to read in file data during a page fault.
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*
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* This function is derived from filemap_nopage, but used for execute in place
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*/
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static struct page *
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xip_file_nopage(struct vm_area_struct * area,
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unsigned long address,
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int *type)
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{
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struct file *file = area->vm_file;
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struct address_space *mapping = file->f_mapping;
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struct inode *inode = mapping->host;
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struct page *page;
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unsigned long size, pgoff, endoff;
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pgoff = ((address - area->vm_start) >> PAGE_CACHE_SHIFT)
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+ area->vm_pgoff;
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endoff = ((area->vm_end - area->vm_start) >> PAGE_CACHE_SHIFT)
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+ area->vm_pgoff;
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size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
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if (pgoff >= size) {
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return NULL;
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}
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page = mapping->a_ops->get_xip_page(mapping, pgoff*(PAGE_SIZE/512), 0);
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if (!IS_ERR(page)) {
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goto out;
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}
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if (PTR_ERR(page) != -ENODATA)
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return NULL;
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/* sparse block */
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if ((area->vm_flags & (VM_WRITE | VM_MAYWRITE)) &&
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(area->vm_flags & (VM_SHARED| VM_MAYSHARE)) &&
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(!(mapping->host->i_sb->s_flags & MS_RDONLY))) {
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/* maybe shared writable, allocate new block */
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page = mapping->a_ops->get_xip_page (mapping,
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pgoff*(PAGE_SIZE/512), 1);
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if (IS_ERR(page))
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return NULL;
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/* unmap page at pgoff from all other vmas */
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__xip_unmap(mapping, pgoff);
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} else {
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/* not shared and writable, use ZERO_PAGE() */
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page = ZERO_PAGE(address);
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}
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out:
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page_cache_get(page);
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return page;
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}
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static struct vm_operations_struct xip_file_vm_ops = {
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.nopage = xip_file_nopage,
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};
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int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
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{
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BUG_ON(!file->f_mapping->a_ops->get_xip_page);
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file_accessed(file);
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vma->vm_ops = &xip_file_vm_ops;
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return 0;
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}
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EXPORT_SYMBOL_GPL(xip_file_mmap);
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static ssize_t
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__xip_file_write(struct file *filp, const char __user *buf,
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size_t count, loff_t pos, loff_t *ppos)
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{
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struct address_space * mapping = filp->f_mapping;
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struct address_space_operations *a_ops = mapping->a_ops;
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struct inode *inode = mapping->host;
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long status = 0;
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struct page *page;
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size_t bytes;
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ssize_t written = 0;
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BUG_ON(!mapping->a_ops->get_xip_page);
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do {
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unsigned long index;
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unsigned long offset;
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size_t copied;
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offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
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index = pos >> PAGE_CACHE_SHIFT;
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bytes = PAGE_CACHE_SIZE - offset;
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if (bytes > count)
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bytes = count;
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/*
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* Bring in the user page that we will copy from _first_.
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* Otherwise there's a nasty deadlock on copying from the
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* same page as we're writing to, without it being marked
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* up-to-date.
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*/
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fault_in_pages_readable(buf, bytes);
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page = a_ops->get_xip_page(mapping,
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index*(PAGE_SIZE/512), 0);
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if (IS_ERR(page) && (PTR_ERR(page) == -ENODATA)) {
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/* we allocate a new page unmap it */
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page = a_ops->get_xip_page(mapping,
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index*(PAGE_SIZE/512), 1);
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if (!IS_ERR(page))
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/* unmap page at pgoff from all other vmas */
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__xip_unmap(mapping, index);
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}
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if (IS_ERR(page)) {
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status = PTR_ERR(page);
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break;
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}
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copied = filemap_copy_from_user(page, offset, buf, bytes);
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flush_dcache_page(page);
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if (likely(copied > 0)) {
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status = copied;
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if (status >= 0) {
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written += status;
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count -= status;
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pos += status;
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buf += status;
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}
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}
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if (unlikely(copied != bytes))
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if (status >= 0)
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status = -EFAULT;
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if (status < 0)
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break;
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} while (count);
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*ppos = pos;
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/*
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* No need to use i_size_read() here, the i_size
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* cannot change under us because we hold i_mutex.
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*/
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if (pos > inode->i_size) {
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i_size_write(inode, pos);
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mark_inode_dirty(inode);
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}
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return written ? written : status;
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}
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ssize_t
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xip_file_write(struct file *filp, const char __user *buf, size_t len,
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loff_t *ppos)
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{
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struct address_space *mapping = filp->f_mapping;
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struct inode *inode = mapping->host;
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size_t count;
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loff_t pos;
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ssize_t ret;
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mutex_lock(&inode->i_mutex);
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if (!access_ok(VERIFY_READ, buf, len)) {
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ret=-EFAULT;
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goto out_up;
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}
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pos = *ppos;
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count = len;
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vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
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/* We can write back this queue in page reclaim */
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current->backing_dev_info = mapping->backing_dev_info;
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ret = generic_write_checks(filp, &pos, &count, S_ISBLK(inode->i_mode));
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if (ret)
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goto out_backing;
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if (count == 0)
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goto out_backing;
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ret = remove_suid(filp->f_dentry);
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if (ret)
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goto out_backing;
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file_update_time(filp);
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ret = __xip_file_write (filp, buf, count, pos, ppos);
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out_backing:
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current->backing_dev_info = NULL;
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out_up:
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mutex_unlock(&inode->i_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(xip_file_write);
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/*
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* truncate a page used for execute in place
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* functionality is analog to block_truncate_page but does use get_xip_page
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* to get the page instead of page cache
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*/
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int
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xip_truncate_page(struct address_space *mapping, loff_t from)
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{
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pgoff_t index = from >> PAGE_CACHE_SHIFT;
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unsigned offset = from & (PAGE_CACHE_SIZE-1);
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unsigned blocksize;
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unsigned length;
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struct page *page;
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void *kaddr;
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BUG_ON(!mapping->a_ops->get_xip_page);
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blocksize = 1 << mapping->host->i_blkbits;
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length = offset & (blocksize - 1);
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/* Block boundary? Nothing to do */
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if (!length)
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return 0;
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length = blocksize - length;
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page = mapping->a_ops->get_xip_page(mapping,
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index*(PAGE_SIZE/512), 0);
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if (!page)
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return -ENOMEM;
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if (unlikely(IS_ERR(page))) {
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if (PTR_ERR(page) == -ENODATA)
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/* Hole? No need to truncate */
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return 0;
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else
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return PTR_ERR(page);
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}
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kaddr = kmap_atomic(page, KM_USER0);
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memset(kaddr + offset, 0, length);
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kunmap_atomic(kaddr, KM_USER0);
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flush_dcache_page(page);
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return 0;
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}
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EXPORT_SYMBOL_GPL(xip_truncate_page);
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