[mirror_ubuntu-focal-kernel.git] / mm / truncate.c

/*
 * mm/truncate.c - code for taking down pages from address_spaces
 *
 * Copyright (C) 2002, Linus Torvalds
 *
 * 10Sep2002	akpm@zip.com.au
 *		Initial version.
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/buffer_head.h>	/* grr. try_to_release_page,
				   do_invalidatepage */


/**
 * do_invalidatepage - invalidate part of all of a page
 * @page: the page which is affected
 * @offset: the index of the truncation point
 *
 * do_invalidatepage() is called when all or part of the page has become
 * invalidated by a truncate operation.
 *
 * do_invalidatepage() does not have to release all buffers, but it must
 * ensure that no dirty buffer is left outside @offset and that no I/O
 * is underway against any of the blocks which are outside the truncation
 * point.  Because the caller is about to free (and possibly reuse) those
 * blocks on-disk.
 */
void do_invalidatepage(struct page *page, unsigned long offset)
{
	void (*invalidatepage)(struct page *, unsigned long);
	invalidatepage = page->mapping->a_ops->invalidatepage;
#ifdef CONFIG_BLOCK
	if (!invalidatepage)
		invalidatepage = block_invalidatepage;
#endif
	if (invalidatepage)
		(*invalidatepage)(page, offset);
}

static inline void truncate_partial_page(struct page *page, unsigned partial)
{
	memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial);
	if (PagePrivate(page))
		do_invalidatepage(page, partial);
}

void cancel_dirty_page(struct page *page, unsigned int account_size)
{
	/* If we're cancelling the page, it had better not be mapped any more */
	if (page_mapped(page)) {
		static unsigned int warncount;

		WARN_ON(++warncount < 5);
	}
		
	if (TestClearPageDirty(page) && account_size)
		task_io_account_cancelled_write(account_size);
}


/*
 * If truncate cannot remove the fs-private metadata from the page, the page
 * becomes anonymous.  It will be left on the LRU and may even be mapped into
 * user pagetables if we're racing with filemap_nopage().
 *
 * We need to bale out if page->mapping is no longer equal to the original
 * mapping.  This happens a) when the VM reclaimed the page while we waited on
 * its lock, b) when a concurrent invalidate_inode_pages got there first and
 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
 */
static void
truncate_complete_page(struct address_space *mapping, struct page *page)
{
	if (page->mapping != mapping)
		return;

	if (PagePrivate(page))
		do_invalidatepage(page, 0);

	cancel_dirty_page(page, PAGE_CACHE_SIZE);

	ClearPageUptodate(page);
	ClearPageMappedToDisk(page);
	remove_from_page_cache(page);
	page_cache_release(page);	/* pagecache ref */
}

/*
 * This is for invalidate_inode_pages().  That function can be called at
 * any time, and is not supposed to throw away dirty pages.  But pages can
 * be marked dirty at any time too, so use remove_mapping which safely
 * discards clean, unused pages.
 *
 * Returns non-zero if the page was successfully invalidated.
 */
static int
invalidate_complete_page(struct address_space *mapping, struct page *page)
{
	int ret;

	if (page->mapping != mapping)
		return 0;

	if (PagePrivate(page) && !try_to_release_page(page, 0))
		return 0;

	ret = remove_mapping(mapping, page);

	return ret;
}

/**
 * truncate_inode_pages - truncate range of pages specified by start and
 * end byte offsets
 * @mapping: mapping to truncate
 * @lstart: offset from which to truncate
 * @lend: offset to which to truncate
 *
 * Truncate the page cache, removing the pages that are between
 * specified offsets (and zeroing out partial page
 * (if lstart is not page aligned)).
 *
 * Truncate takes two passes - the first pass is nonblocking.  It will not
 * block on page locks and it will not block on writeback.  The second pass
 * will wait.  This is to prevent as much IO as possible in the affected region.
 * The first pass will remove most pages, so the search cost of the second pass
 * is low.
 *
 * When looking at page->index outside the page lock we need to be careful to
 * copy it into a local to avoid races (it could change at any time).
 *
 * We pass down the cache-hot hint to the page freeing code.  Even if the
 * mapping is large, it is probably the case that the final pages are the most
 * recently touched, and freeing happens in ascending file offset order.
 */
void truncate_inode_pages_range(struct address_space *mapping,
				loff_t lstart, loff_t lend)
{
	const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
	pgoff_t end;
	const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
	struct pagevec pvec;
	pgoff_t next;
	int i;

	if (mapping->nrpages == 0)
		return;

	BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1));
	end = (lend >> PAGE_CACHE_SHIFT);

	pagevec_init(&pvec, 0);
	next = start;
	while (next <= end &&
	       pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];
			pgoff_t page_index = page->index;

			if (page_index > end) {
				next = page_index;
				break;
			}

			if (page_index > next)
				next = page_index;
			next++;
			if (TestSetPageLocked(page))
				continue;
			if (PageWriteback(page)) {
				unlock_page(page);
				continue;
			}
			truncate_complete_page(mapping, page);
			unlock_page(page);
		}
		pagevec_release(&pvec);
		cond_resched();
	}

	if (partial) {
		struct page *page = find_lock_page(mapping, start - 1);
		if (page) {
			wait_on_page_writeback(page);
			truncate_partial_page(page, partial);
			unlock_page(page);
			page_cache_release(page);
		}
	}

	next = start;
	for ( ; ; ) {
		cond_resched();
		if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
			if (next == start)
				break;
			next = start;
			continue;
		}
		if (pvec.pages[0]->index > end) {
			pagevec_release(&pvec);
			break;
		}
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];

			if (page->index > end)
				break;
			lock_page(page);
			wait_on_page_writeback(page);
			if (page->index > next)
				next = page->index;
			next++;
			truncate_complete_page(mapping, page);
			unlock_page(page);
		}
		pagevec_release(&pvec);
	}
}
EXPORT_SYMBOL(truncate_inode_pages_range);

/**
 * truncate_inode_pages - truncate *all* the pages from an offset
 * @mapping: mapping to truncate
 * @lstart: offset from which to truncate
 *
 * Called under (and serialised by) inode->i_mutex.
 */
void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
{
	truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
}
EXPORT_SYMBOL(truncate_inode_pages);

/**
 * 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];
			pgoff_t index;
			int lock_failed;

			lock_failed = TestSetPageLocked(page);

			/*
			 * We really shouldn't be looking at the ->index of an
			 * unlocked page.  But we're not allowed to lock these
			 * pages.  So we rely upon nobody altering the ->index
			 * of this (pinned-by-us) page.
			 */
			index = page->index;
			if (index > next)
				next = index;
			next++;
			if (lock_failed)
				continue;

			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);
	}
	return ret;
}

unsigned long invalidate_inode_pages(struct address_space *mapping)
{
	return invalidate_mapping_pages(mapping, 0, ~0UL);
}
EXPORT_SYMBOL(invalidate_inode_pages);

/*
 * This is like invalidate_complete_page(), except it ignores the page's
 * refcount.  We do this because invalidate_inode_pages2() needs stronger
 * invalidation guarantees, and cannot afford to leave pages behind because
 * shrink_list() has a temp ref on them, or because they're transiently sitting
 * in the lru_cache_add() pagevecs.
 */
static int
invalidate_complete_page2(struct address_space *mapping, struct page *page)
{
	if (page->mapping != mapping)
		return 0;

	if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL))
		return 0;

	write_lock_irq(&mapping->tree_lock);
	if (PageDirty(page))
		goto failed;

	BUG_ON(PagePrivate(page));
	__remove_from_page_cache(page);
	write_unlock_irq(&mapping->tree_lock);
	ClearPageUptodate(page);
	page_cache_release(page);	/* pagecache ref */
	return 1;
failed:
	write_unlock_irq(&mapping->tree_lock);
	return 0;
}

/**
 * invalidate_inode_pages2_range - remove range of pages from an address_space
 * @mapping: the address_space
 * @start: the page offset 'from' which to invalidate
 * @end: the page offset 'to' which to invalidate (inclusive)
 *
 * Any pages which are found to be mapped into pagetables are unmapped prior to
 * invalidation.
 *
 * Returns -EIO if any pages could not be invalidated.
 */
int invalidate_inode_pages2_range(struct address_space *mapping,
				  pgoff_t start, pgoff_t end)
{
	struct pagevec pvec;
	pgoff_t next;
	int i;
	int ret = 0;
	int did_range_unmap = 0;
	int wrapped = 0;

	pagevec_init(&pvec, 0);
	next = start;
	while (next <= end && !ret && !wrapped &&
		pagevec_lookup(&pvec, mapping, next,
			min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
		for (i = 0; !ret && i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];
			pgoff_t page_index;

			lock_page(page);
			if (page->mapping != mapping) {
				unlock_page(page);
				continue;
			}
			page_index = page->index;
			next = page_index + 1;
			if (next == 0)
				wrapped = 1;
			if (page_index > end) {
				unlock_page(page);
				break;
			}
			wait_on_page_writeback(page);
			while (page_mapped(page)) {
				if (!did_range_unmap) {
					/*
					 * Zap the rest of the file in one hit.
					 */
					unmap_mapping_range(mapping,
					   (loff_t)page_index<<PAGE_CACHE_SHIFT,
					   (loff_t)(end - page_index + 1)
							<< PAGE_CACHE_SHIFT,
					    0);
					did_range_unmap = 1;
				} else {
					/*
					 * Just zap this page
					 */
					unmap_mapping_range(mapping,
					  (loff_t)page_index<<PAGE_CACHE_SHIFT,
					  PAGE_CACHE_SIZE, 0);
				}
			}
			if (!invalidate_complete_page2(mapping, page))
				ret = -EIO;
			unlock_page(page);
		}
		pagevec_release(&pvec);
		cond_resched();
	}
	WARN_ON_ONCE(ret);
	return ret;
}
EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);

/**
 * invalidate_inode_pages2 - remove all pages from an address_space
 * @mapping: the address_space
 *
 * Any pages which are found to be mapped into pagetables are unmapped prior to
 * invalidation.
 *
 * Returns -EIO if any pages could not be invalidated.
 */
int invalidate_inode_pages2(struct address_space *mapping)
{
	return invalidate_inode_pages2_range(mapping, 0, -1);
}
EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* mm/truncate.c - code for taking down pages from address_spaces
	3	*
	4	* Copyright (C) 2002, Linus Torvalds
	5	*
	6	* 10Sep2002 akpm@zip.com.au
	7	* Initial version.
	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/mm.h>
0fd0e6b0	12	#include <linux/swap.h>
1da177e4 LT	13	#include <linux/module.h>
	14	#include <linux/pagemap.h>
	15	#include <linux/pagevec.h>
e08748ce	16	#include <linux/task_io_accounting_ops.h>
1da177e4	17	#include <linux/buffer_head.h> /* grr. try_to_release_page,
aaa4059b	18	do_invalidatepage */
1da177e4 LT	19
1da177e4 LT	20
cf9a2ae8 DH	21	/**
	22	* do_invalidatepage - invalidate part of all of a page
	23	* @page: the page which is affected
	24	* @offset: the index of the truncation point
	25	*
	26	* do_invalidatepage() is called when all or part of the page has become
	27	* invalidated by a truncate operation.
	28	*
	29	* do_invalidatepage() does not have to release all buffers, but it must
	30	* ensure that no dirty buffer is left outside @offset and that no I/O
	31	* is underway against any of the blocks which are outside the truncation
	32	* point. Because the caller is about to free (and possibly reuse) those
	33	* blocks on-disk.
	34	*/
	35	void do_invalidatepage(struct page *page, unsigned long offset)
	36	{
	37	void (invalidatepage)(struct page , unsigned long);
	38	invalidatepage = page->mapping->a_ops->invalidatepage;
9361401e	39	#ifdef CONFIG_BLOCK
cf9a2ae8 DH	40	if (!invalidatepage)
cf9a2ae8 DH	41	invalidatepage = block_invalidatepage;
9361401e	42	#endif
cf9a2ae8 DH	43	if (invalidatepage)
	44	(*invalidatepage)(page, offset);
	45	}
	46
1da177e4 LT	47	static inline void truncate_partial_page(struct page *page, unsigned partial)
	48	{
	49	memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial);
	50	if (PagePrivate(page))
	51	do_invalidatepage(page, partial);
	52	}
	53
fba2591b LT	54	void cancel_dirty_page(struct page *page, unsigned int account_size)
	55	{
	56	/* If we're cancelling the page, it had better not be mapped any more */
	57	if (page_mapped(page)) {
	58	static unsigned int warncount;
	59
	60	WARN_ON(++warncount < 5);
	61	}
	62
	63	if (TestClearPageDirty(page) && account_size)
	64	task_io_account_cancelled_write(account_size);
	65	}
	66
	67
1da177e4 LT	68	/*
	69	* If truncate cannot remove the fs-private metadata from the page, the page
	70	* becomes anonymous. It will be left on the LRU and may even be mapped into
	71	* user pagetables if we're racing with filemap_nopage().
	72	*
	73	* We need to bale out if page->mapping is no longer equal to the original
	74	* mapping. This happens a) when the VM reclaimed the page while we waited on
	75	* its lock, b) when a concurrent invalidate_inode_pages got there first and
	76	* c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
	77	*/
	78	static void
	79	truncate_complete_page(struct address_space mapping, struct page page)
	80	{
	81	if (page->mapping != mapping)
	82	return;
	83
	84	if (PagePrivate(page))
	85	do_invalidatepage(page, 0);
	86
fba2591b LT	87	cancel_dirty_page(page, PAGE_CACHE_SIZE);
fba2591b LT	88
1da177e4 LT	89	ClearPageUptodate(page);
	90	ClearPageMappedToDisk(page);
	91	remove_from_page_cache(page);
	92	page_cache_release(page); /* pagecache ref */
	93	}
	94
	95	/*
	96	* This is for invalidate_inode_pages(). That function can be called at
	97	* any time, and is not supposed to throw away dirty pages. But pages can
0fd0e6b0 NP	98	* be marked dirty at any time too, so use remove_mapping which safely
0fd0e6b0 NP	99	* discards clean, unused pages.
1da177e4 LT	100	*
	101	* Returns non-zero if the page was successfully invalidated.
	102	*/
	103	static int
	104	invalidate_complete_page(struct address_space mapping, struct page page)
	105	{
0fd0e6b0 NP	106	int ret;
0fd0e6b0 NP	107
1da177e4 LT	108	if (page->mapping != mapping)
	109	return 0;
	110
	111	if (PagePrivate(page) && !try_to_release_page(page, 0))
	112	return 0;
	113
0fd0e6b0	114	ret = remove_mapping(mapping, page);
0fd0e6b0 NP	115
0fd0e6b0 NP	116	return ret;
1da177e4 LT	117	}
	118
	119	/**
d7339071 HR	120	* truncate_inode_pages - truncate range of pages specified by start and
d7339071 HR	121	* end byte offsets
1da177e4 LT	122	* @mapping: mapping to truncate
1da177e4 LT	123	* @lstart: offset from which to truncate
d7339071	124	* @lend: offset to which to truncate
1da177e4	125	*
d7339071 HR	126	* Truncate the page cache, removing the pages that are between
	127	* specified offsets (and zeroing out partial page
	128	* (if lstart is not page aligned)).
1da177e4 LT	129	*
	130	* Truncate takes two passes - the first pass is nonblocking. It will not
	131	* block on page locks and it will not block on writeback. The second pass
	132	* will wait. This is to prevent as much IO as possible in the affected region.
	133	* The first pass will remove most pages, so the search cost of the second pass
	134	* is low.
	135	*
	136	* When looking at page->index outside the page lock we need to be careful to
	137	* copy it into a local to avoid races (it could change at any time).
	138	*
	139	* We pass down the cache-hot hint to the page freeing code. Even if the
	140	* mapping is large, it is probably the case that the final pages are the most
	141	* recently touched, and freeing happens in ascending file offset order.
1da177e4	142	*/
d7339071 HR	143	void truncate_inode_pages_range(struct address_space *mapping,
d7339071 HR	144	loff_t lstart, loff_t lend)
1da177e4 LT	145	{
1da177e4 LT	146	const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
d7339071	147	pgoff_t end;
1da177e4 LT	148	const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
	149	struct pagevec pvec;
	150	pgoff_t next;
	151	int i;
	152
	153	if (mapping->nrpages == 0)
	154	return;
	155
d7339071 HR	156	BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1));
	157	end = (lend >> PAGE_CACHE_SHIFT);
	158
1da177e4 LT	159	pagevec_init(&pvec, 0);
1da177e4 LT	160	next = start;
d7339071 HR	161	while (next <= end &&
d7339071 HR	162	pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
1da177e4 LT	163	for (i = 0; i < pagevec_count(&pvec); i++) {
	164	struct page *page = pvec.pages[i];
	165	pgoff_t page_index = page->index;
	166
d7339071 HR	167	if (page_index > end) {
	168	next = page_index;
	169	break;
	170	}
	171
1da177e4 LT	172	if (page_index > next)
	173	next = page_index;
	174	next++;
	175	if (TestSetPageLocked(page))
	176	continue;
	177	if (PageWriteback(page)) {
	178	unlock_page(page);
	179	continue;
	180	}
	181	truncate_complete_page(mapping, page);
	182	unlock_page(page);
	183	}
	184	pagevec_release(&pvec);
	185	cond_resched();
	186	}
	187
	188	if (partial) {
	189	struct page *page = find_lock_page(mapping, start - 1);
	190	if (page) {
	191	wait_on_page_writeback(page);
	192	truncate_partial_page(page, partial);
	193	unlock_page(page);
	194	page_cache_release(page);
	195	}
	196	}
	197
	198	next = start;
	199	for ( ; ; ) {
	200	cond_resched();
	201	if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
	202	if (next == start)
	203	break;
	204	next = start;
	205	continue;
	206	}
d7339071 HR	207	if (pvec.pages[0]->index > end) {
	208	pagevec_release(&pvec);
	209	break;
	210	}
1da177e4 LT	211	for (i = 0; i < pagevec_count(&pvec); i++) {
	212	struct page *page = pvec.pages[i];
	213
d7339071 HR	214	if (page->index > end)
d7339071 HR	215	break;
1da177e4 LT	216	lock_page(page);
	217	wait_on_page_writeback(page);
	218	if (page->index > next)
	219	next = page->index;
	220	next++;
	221	truncate_complete_page(mapping, page);
	222	unlock_page(page);
	223	}
	224	pagevec_release(&pvec);
	225	}
	226	}
d7339071	227	EXPORT_SYMBOL(truncate_inode_pages_range);
1da177e4	228
d7339071 HR	229	/**
	230	* truncate_inode_pages - truncate all the pages from an offset
	231	* @mapping: mapping to truncate
	232	* @lstart: offset from which to truncate
	233	*
1b1dcc1b	234	* Called under (and serialised by) inode->i_mutex.
d7339071 HR	235	*/
	236	void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
	237	{
	238	truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
	239	}
1da177e4 LT	240	EXPORT_SYMBOL(truncate_inode_pages);
	241
	242	/**
	243	* invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
	244	* @mapping: the address_space which holds the pages to invalidate
	245	* @start: the offset 'from' which to invalidate
	246	* @end: the offset 'to' which to invalidate (inclusive)
	247	*
	248	* This function only removes the unlocked pages, if you want to
	249	* remove all the pages of one inode, you must call truncate_inode_pages.
	250	*
	251	* invalidate_mapping_pages() will not block on IO activity. It will not
	252	* invalidate pages which are dirty, locked, under writeback or mapped into
	253	* pagetables.
	254	*/
	255	unsigned long invalidate_mapping_pages(struct address_space *mapping,
	256	pgoff_t start, pgoff_t end)
	257	{
	258	struct pagevec pvec;
	259	pgoff_t next = start;
	260	unsigned long ret = 0;
	261	int i;
	262
	263	pagevec_init(&pvec, 0);
	264	while (next <= end &&
	265	pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
	266	for (i = 0; i < pagevec_count(&pvec); i++) {
	267	struct page *page = pvec.pages[i];
e0f23603 N	268	pgoff_t index;
e0f23603 N	269	int lock_failed;
1da177e4	270
e0f23603 N	271	lock_failed = TestSetPageLocked(page);
	272
	273	/*
	274	* We really shouldn't be looking at the ->index of an
	275	* unlocked page. But we're not allowed to lock these
	276	* pages. So we rely upon nobody altering the ->index
	277	* of this (pinned-by-us) page.
	278	*/
	279	index = page->index;
	280	if (index > next)
	281	next = index;
1da177e4	282	next++;
e0f23603 N	283	if (lock_failed)
	284	continue;
	285
1da177e4 LT	286	if (PageDirty(page) \|\| PageWriteback(page))
	287	goto unlock;
	288	if (page_mapped(page))
	289	goto unlock;
	290	ret += invalidate_complete_page(mapping, page);
	291	unlock:
	292	unlock_page(page);
	293	if (next > end)
	294	break;
	295	}
	296	pagevec_release(&pvec);
1da177e4 LT	297	}
	298	return ret;
	299	}
	300
	301	unsigned long invalidate_inode_pages(struct address_space *mapping)
	302	{
	303	return invalidate_mapping_pages(mapping, 0, ~0UL);
	304	}
1da177e4 LT	305	EXPORT_SYMBOL(invalidate_inode_pages);
1da177e4 LT	306
bd4c8ce4 AM	307	/*
	308	* This is like invalidate_complete_page(), except it ignores the page's
	309	* refcount. We do this because invalidate_inode_pages2() needs stronger
	310	* invalidation guarantees, and cannot afford to leave pages behind because
	311	* shrink_list() has a temp ref on them, or because they're transiently sitting
	312	* in the lru_cache_add() pagevecs.
	313	*/
	314	static int
	315	invalidate_complete_page2(struct address_space mapping, struct page page)
	316	{
	317	if (page->mapping != mapping)
	318	return 0;
	319
887ed2f3	320	if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL))
bd4c8ce4 AM	321	return 0;
	322
	323	write_lock_irq(&mapping->tree_lock);
	324	if (PageDirty(page))
	325	goto failed;
	326
	327	BUG_ON(PagePrivate(page));
	328	__remove_from_page_cache(page);
	329	write_unlock_irq(&mapping->tree_lock);
	330	ClearPageUptodate(page);
	331	page_cache_release(page); /* pagecache ref */
	332	return 1;
	333	failed:
	334	write_unlock_irq(&mapping->tree_lock);
	335	return 0;
	336	}
	337
1da177e4 LT	338	/**
1da177e4 LT	339	* invalidate_inode_pages2_range - remove range of pages from an address_space
67be2dd1	340	* @mapping: the address_space
1da177e4 LT	341	* @start: the page offset 'from' which to invalidate
	342	* @end: the page offset 'to' which to invalidate (inclusive)
	343	*
	344	* Any pages which are found to be mapped into pagetables are unmapped prior to
	345	* invalidation.
	346	*
	347	* Returns -EIO if any pages could not be invalidated.
	348	*/
	349	int invalidate_inode_pages2_range(struct address_space *mapping,
	350	pgoff_t start, pgoff_t end)
	351	{
	352	struct pagevec pvec;
	353	pgoff_t next;
	354	int i;
	355	int ret = 0;
	356	int did_range_unmap = 0;
	357	int wrapped = 0;
	358
	359	pagevec_init(&pvec, 0);
	360	next = start;
	361	while (next <= end && !ret && !wrapped &&
	362	pagevec_lookup(&pvec, mapping, next,
	363	min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
	364	for (i = 0; !ret && i < pagevec_count(&pvec); i++) {
	365	struct page *page = pvec.pages[i];
	366	pgoff_t page_index;
1da177e4 LT	367
	368	lock_page(page);
	369	if (page->mapping != mapping) {
	370	unlock_page(page);
	371	continue;
	372	}
	373	page_index = page->index;
	374	next = page_index + 1;
	375	if (next == 0)
	376	wrapped = 1;
	377	if (page_index > end) {
	378	unlock_page(page);
	379	break;
	380	}
	381	wait_on_page_writeback(page);
	382	while (page_mapped(page)) {
	383	if (!did_range_unmap) {
	384	/*
	385	* Zap the rest of the file in one hit.
	386	*/
	387	unmap_mapping_range(mapping,
479ef592 OD	388	(loff_t)page_index<<PAGE_CACHE_SHIFT,
479ef592 OD	389	(loff_t)(end - page_index + 1)
1da177e4 LT	390	<< PAGE_CACHE_SHIFT,
	391	0);
	392	did_range_unmap = 1;
	393	} else {
	394	/*
	395	* Just zap this page
	396	*/
	397	unmap_mapping_range(mapping,
479ef592	398	(loff_t)page_index<<PAGE_CACHE_SHIFT,
1da177e4 LT	399	PAGE_CACHE_SIZE, 0);
	400	}
	401	}
fba2591b	402	if (!invalidate_complete_page2(mapping, page))
1da177e4	403	ret = -EIO;
1da177e4 LT	404	unlock_page(page);
	405	}
	406	pagevec_release(&pvec);
	407	cond_resched();
	408	}
8258d4a5	409	WARN_ON_ONCE(ret);
1da177e4 LT	410	return ret;
	411	}
	412	EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
	413
	414	/**
	415	* invalidate_inode_pages2 - remove all pages from an address_space
67be2dd1	416	* @mapping: the address_space
1da177e4 LT	417	*
	418	* Any pages which are found to be mapped into pagetables are unmapped prior to
	419	* invalidation.
	420	*
	421	* Returns -EIO if any pages could not be invalidated.
	422	*/
	423	int invalidate_inode_pages2(struct address_space *mapping)
	424	{
	425	return invalidate_inode_pages2_range(mapping, 0, -1);
	426	}
	427	EXPORT_SYMBOL_GPL(invalidate_inode_pages2);