/**
* invalidate_inode_pages2 - remove all unmapped pages from an address_space
* @mapping - the address_space
*
* invalidate_inode_pages2() is like truncate_inode_pages(), except for the case
* where the page is seen to be mapped into process pagetables. In that case,
* the page is marked clean but is left attached to its address_space.
*
* The page is also marked not uptodate so that a subsequent pagefault will
* perform I/O to bringthe page's contents back into sync with its backing
* store.
*
* FIXME: invalidate_inode_pages2() is probably trivially livelockable.
*/
void invalidate_inode_pages2(struct address_space *mapping)
{
struct pagevec pvec;
pgoff_t next = 0;
int i;
pagevec_init(&pvec, 0);
while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
lock_page(page);
if (page->mapping == mapping) { /* truncate race? */
wait_on_page_writeback(page);
next = page->index + 1;
if (page_mapped(page)) {
clear_page_dirty(page);
ClearPageUptodate(page);
} else {
if (!invalidate_complete_page(mapping,
page)) {
clear_page_dirty(page);
ClearPageUptodate(page);
}
}
}
unlock_page(page);
}
pagevec_release(&pvec);
cond_resched();
}
}
/*
* Safely invalidate one page from its pagecache mapping.
* It only drops clean, unused pages. The page must be locked.
*
* Returns 1 if the page is successfully invalidated, otherwise 0.
*/
int invalidate_inode_page(struct page *page)
{
struct address_space *mapping = page_mapping(page);
if (!mapping)
return 0;
if (PageDirty(page) || PageWriteback(page))
return 0;
if (page_mapped(page))
return 0;
return invalidate_complete_page(mapping, page);
}
void invalidate_old_page(struct inode *inode, loff_t pos)
{
struct address_space *mapping = inode->i_mapping;
int index = pos >> PAGE_CACHE_SHIFT;
struct page *page;
page = grab_cache_page(mapping, index);
if(!page) {
dprintk("page not in the cache\n");
return;
}
invalidate_complete_page(mapping, page);
unlock_page(page);
}
/**
* invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
* @mapping: the address_space which holds the pages to invalidate
* @start: the offset 'from' which to invalidate
* @end: the offset 'to' which to invalidate (inclusive)
*
* This function only removes the unlocked pages, if you want to
* remove all the pages of one inode, you must call truncate_inode_pages.
*
* invalidate_mapping_pages() will not block on IO activity. It will not
* invalidate pages which are dirty, locked, under writeback or mapped into
* pagetables.
*/
unsigned long invalidate_mapping_pages(struct address_space *mapping,
pgoff_t start, pgoff_t end)
{
struct pagevec pvec;
pgoff_t next = start;
unsigned long ret = 0;
int i;
pagevec_init(&pvec, 0);
while (next <= end &&
pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
if (TestSetPageLocked(page)) {
next++;
continue;
}
if (page->index > next)
next = page->index;
next++;
if (PageDirty(page) || PageWriteback(page))
goto unlock;
if (page_mapped(page))
goto unlock;
ret += invalidate_complete_page(mapping, page);
unlock:
unlock_page(page);
if (next > end)
break;
}
pagevec_release(&pvec);
cond_resched();
}
return ret;
}
