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67be2dd1ba
Some KernelDoc descriptions are updated to match the current code. No code changes. Signed-off-by: Martin Waitz <tali@admingilde.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
337 lines
8.9 KiB
C
337 lines
8.9 KiB
C
/*
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* mm/truncate.c - code for taking down pages from address_spaces
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*
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* Copyright (C) 2002, Linus Torvalds
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*
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* 10Sep2002 akpm@zip.com.au
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* Initial version.
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/pagemap.h>
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#include <linux/pagevec.h>
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#include <linux/buffer_head.h> /* grr. try_to_release_page,
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block_invalidatepage */
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static int do_invalidatepage(struct page *page, unsigned long offset)
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{
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int (*invalidatepage)(struct page *, unsigned long);
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invalidatepage = page->mapping->a_ops->invalidatepage;
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if (invalidatepage == NULL)
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invalidatepage = block_invalidatepage;
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return (*invalidatepage)(page, offset);
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}
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static inline void truncate_partial_page(struct page *page, unsigned partial)
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{
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memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial);
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if (PagePrivate(page))
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do_invalidatepage(page, partial);
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}
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/*
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* If truncate cannot remove the fs-private metadata from the page, the page
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* becomes anonymous. It will be left on the LRU and may even be mapped into
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* user pagetables if we're racing with filemap_nopage().
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*
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* We need to bale out if page->mapping is no longer equal to the original
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* mapping. This happens a) when the VM reclaimed the page while we waited on
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* its lock, b) when a concurrent invalidate_inode_pages got there first and
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* c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
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*/
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static void
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truncate_complete_page(struct address_space *mapping, struct page *page)
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{
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if (page->mapping != mapping)
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return;
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if (PagePrivate(page))
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do_invalidatepage(page, 0);
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clear_page_dirty(page);
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ClearPageUptodate(page);
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ClearPageMappedToDisk(page);
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remove_from_page_cache(page);
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page_cache_release(page); /* pagecache ref */
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}
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/*
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* This is for invalidate_inode_pages(). That function can be called at
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* any time, and is not supposed to throw away dirty pages. But pages can
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* be marked dirty at any time too. So we re-check the dirtiness inside
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* ->tree_lock. That provides exclusion against the __set_page_dirty
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* functions.
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*
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* Returns non-zero if the page was successfully invalidated.
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*/
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static int
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invalidate_complete_page(struct address_space *mapping, struct page *page)
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{
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if (page->mapping != mapping)
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return 0;
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if (PagePrivate(page) && !try_to_release_page(page, 0))
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return 0;
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write_lock_irq(&mapping->tree_lock);
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if (PageDirty(page)) {
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write_unlock_irq(&mapping->tree_lock);
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return 0;
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}
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BUG_ON(PagePrivate(page));
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__remove_from_page_cache(page);
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write_unlock_irq(&mapping->tree_lock);
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ClearPageUptodate(page);
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page_cache_release(page); /* pagecache ref */
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return 1;
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}
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/**
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* truncate_inode_pages - truncate *all* the pages from an offset
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* @mapping: mapping to truncate
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* @lstart: offset from which to truncate
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*
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* Truncate the page cache at a set offset, removing the pages that are beyond
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* that offset (and zeroing out partial pages).
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*
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* Truncate takes two passes - the first pass is nonblocking. It will not
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* block on page locks and it will not block on writeback. The second pass
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* will wait. This is to prevent as much IO as possible in the affected region.
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* The first pass will remove most pages, so the search cost of the second pass
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* is low.
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*
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* When looking at page->index outside the page lock we need to be careful to
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* copy it into a local to avoid races (it could change at any time).
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*
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* We pass down the cache-hot hint to the page freeing code. Even if the
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* mapping is large, it is probably the case that the final pages are the most
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* recently touched, and freeing happens in ascending file offset order.
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*
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* Called under (and serialised by) inode->i_sem.
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*/
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void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
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{
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const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
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const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
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struct pagevec pvec;
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pgoff_t next;
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int i;
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if (mapping->nrpages == 0)
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return;
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pagevec_init(&pvec, 0);
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next = start;
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while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
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for (i = 0; i < pagevec_count(&pvec); i++) {
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struct page *page = pvec.pages[i];
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pgoff_t page_index = page->index;
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if (page_index > next)
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next = page_index;
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next++;
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if (TestSetPageLocked(page))
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continue;
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if (PageWriteback(page)) {
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unlock_page(page);
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continue;
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}
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truncate_complete_page(mapping, page);
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unlock_page(page);
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}
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pagevec_release(&pvec);
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cond_resched();
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}
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if (partial) {
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struct page *page = find_lock_page(mapping, start - 1);
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if (page) {
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wait_on_page_writeback(page);
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truncate_partial_page(page, partial);
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unlock_page(page);
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page_cache_release(page);
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}
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}
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next = start;
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for ( ; ; ) {
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cond_resched();
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if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
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if (next == start)
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break;
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next = start;
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continue;
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}
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for (i = 0; i < pagevec_count(&pvec); i++) {
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struct page *page = pvec.pages[i];
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lock_page(page);
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wait_on_page_writeback(page);
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if (page->index > next)
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next = page->index;
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next++;
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truncate_complete_page(mapping, page);
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unlock_page(page);
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}
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pagevec_release(&pvec);
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}
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}
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EXPORT_SYMBOL(truncate_inode_pages);
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/**
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* invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
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* @mapping: the address_space which holds the pages to invalidate
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* @start: the offset 'from' which to invalidate
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* @end: the offset 'to' which to invalidate (inclusive)
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*
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* This function only removes the unlocked pages, if you want to
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* remove all the pages of one inode, you must call truncate_inode_pages.
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*
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* invalidate_mapping_pages() will not block on IO activity. It will not
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* invalidate pages which are dirty, locked, under writeback or mapped into
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* pagetables.
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*/
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unsigned long invalidate_mapping_pages(struct address_space *mapping,
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pgoff_t start, pgoff_t end)
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{
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struct pagevec pvec;
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pgoff_t next = start;
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unsigned long ret = 0;
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int i;
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pagevec_init(&pvec, 0);
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while (next <= end &&
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pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
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for (i = 0; i < pagevec_count(&pvec); i++) {
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struct page *page = pvec.pages[i];
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if (TestSetPageLocked(page)) {
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next++;
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continue;
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}
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if (page->index > next)
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next = page->index;
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next++;
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if (PageDirty(page) || PageWriteback(page))
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goto unlock;
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if (page_mapped(page))
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goto unlock;
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ret += invalidate_complete_page(mapping, page);
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unlock:
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unlock_page(page);
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if (next > end)
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break;
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}
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pagevec_release(&pvec);
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cond_resched();
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}
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return ret;
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}
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unsigned long invalidate_inode_pages(struct address_space *mapping)
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{
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return invalidate_mapping_pages(mapping, 0, ~0UL);
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}
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EXPORT_SYMBOL(invalidate_inode_pages);
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/**
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* invalidate_inode_pages2_range - remove range of pages from an address_space
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* @mapping: the address_space
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* @start: the page offset 'from' which to invalidate
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* @end: the page offset 'to' which to invalidate (inclusive)
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*
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* Any pages which are found to be mapped into pagetables are unmapped prior to
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* invalidation.
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*
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* Returns -EIO if any pages could not be invalidated.
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*/
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int invalidate_inode_pages2_range(struct address_space *mapping,
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pgoff_t start, pgoff_t end)
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{
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struct pagevec pvec;
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pgoff_t next;
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int i;
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int ret = 0;
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int did_range_unmap = 0;
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int wrapped = 0;
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pagevec_init(&pvec, 0);
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next = start;
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while (next <= end && !ret && !wrapped &&
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pagevec_lookup(&pvec, mapping, next,
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min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
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for (i = 0; !ret && i < pagevec_count(&pvec); i++) {
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struct page *page = pvec.pages[i];
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pgoff_t page_index;
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int was_dirty;
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lock_page(page);
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if (page->mapping != mapping) {
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unlock_page(page);
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continue;
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}
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page_index = page->index;
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next = page_index + 1;
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if (next == 0)
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wrapped = 1;
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if (page_index > end) {
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unlock_page(page);
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break;
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}
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wait_on_page_writeback(page);
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while (page_mapped(page)) {
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if (!did_range_unmap) {
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/*
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* Zap the rest of the file in one hit.
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*/
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unmap_mapping_range(mapping,
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page_index << PAGE_CACHE_SHIFT,
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(end - page_index + 1)
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<< PAGE_CACHE_SHIFT,
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0);
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did_range_unmap = 1;
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} else {
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/*
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* Just zap this page
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*/
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unmap_mapping_range(mapping,
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page_index << PAGE_CACHE_SHIFT,
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PAGE_CACHE_SIZE, 0);
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}
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}
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was_dirty = test_clear_page_dirty(page);
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if (!invalidate_complete_page(mapping, page)) {
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if (was_dirty)
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set_page_dirty(page);
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ret = -EIO;
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}
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unlock_page(page);
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}
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pagevec_release(&pvec);
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cond_resched();
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
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/**
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* invalidate_inode_pages2 - remove all pages from an address_space
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* @mapping: the address_space
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*
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* Any pages which are found to be mapped into pagetables are unmapped prior to
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* invalidation.
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*
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* Returns -EIO if any pages could not be invalidated.
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*/
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int invalidate_inode_pages2(struct address_space *mapping)
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{
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return invalidate_inode_pages2_range(mapping, 0, -1);
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}
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EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
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