1 files changed, 336 insertions, 0 deletions
diff --git a/mm/truncate.c b/mm/truncate.c
new file mode 100644
index 000000000000..c9a63f0b69a2
--- /dev/null
+++ b/mm/truncate.c
@@ -0,0 +1,336 @@
+/*
+ * 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/module.h>
+#include <linux/pagemap.h>
+#include <linux/pagevec.h>
+#include <linux/buffer_head.h>  /* grr. try_to_release_page,
+                                   block_invalidatepage */
+static int do_invalidatepage(struct page *page, unsigned long offset)
+{
+        int (*invalidatepage)(struct page *, unsigned long);
+        invalidatepage = page->mapping->a_ops->invalidatepage;
+        if (invalidatepage == NULL)
+                invalidatepage = block_invalidatepage;
+        return (*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);
+}
+/*
+ * 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);
+        clear_page_dirty(page);
+        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 we re-check the dirtiness inside
+ * ->tree_lock.  That provides exclusion against the __set_page_dirty
+ * functions.
+ *
+ * Returns non-zero if the page was successfully invalidated.
+ */
+static int
+invalidate_complete_page(struct address_space *mapping, struct page *page)
+{
+        if (page->mapping != mapping)
+                return 0;
+        if (PagePrivate(page) && !try_to_release_page(page, 0))
+                return 0;
+        write_lock_irq(&mapping->tree_lock);
+        if (PageDirty(page)) {
+                write_unlock_irq(&mapping->tree_lock);
+                return 0;
+        }
+        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;
+}
+/**
+ * truncate_inode_pages - truncate *all* the pages from an offset
+ * @mapping: mapping to truncate
+ * @lstart: offset from which to truncate
+ *
+ * Truncate the page cache at a set offset, removing the pages that are beyond
+ * that offset (and zeroing out partial pages).
+ *
+ * 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.
+ *
+ * Called under (and serialised by) inode->i_sem.
+ */
+void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
+{
+        const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
+        const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
+        struct pagevec pvec;
+        pgoff_t next;
+        int i;
+        if (mapping->nrpages == 0)
+                return;
+        pagevec_init(&pvec, 0);
+        next = start;
+        while (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 > 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;
+                }
+                for (i = 0; i < pagevec_count(&pvec); i++) {
+                        struct page *page = pvec.pages[i];
+                        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);
+/**
+ * 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;
+}
+unsigned long invalidate_inode_pages(struct address_space *mapping)
+{
+        return invalidate_mapping_pages(mapping, 0, ~0UL);
+}
+EXPORT_SYMBOL(invalidate_inode_pages);
+/**
+ * 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;
+                        int was_dirty;
+                        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,
+                                            page_index << PAGE_CACHE_SHIFT,
+                                            (end - page_index + 1)
+                                                        << PAGE_CACHE_SHIFT,
+                                            0);
+                                        did_range_unmap = 1;
+                                } else {
+                                        /*
+                                         * Just zap this page
+                                         */
+                                        unmap_mapping_range(mapping,
+                                          page_index << PAGE_CACHE_SHIFT,
+                                          PAGE_CACHE_SIZE, 0);
+                                }
+                        }
+                        was_dirty = test_clear_page_dirty(page);
+                        if (!invalidate_complete_page(mapping, page)) {
+                                if (was_dirty)
+                                        set_page_dirty(page);
+                                ret = -EIO;
+                        }
+                        unlock_page(page);
+                }
+                pagevec_release(&pvec);
+                cond_resched();
+        }
+        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);

diff --git a/mm/truncate.c b/mm/truncate.c new file mode 100644 index 000000000000..c9a63f0b69a2 --- /dev/null +++ b/mm/truncate.c
@@ -0,0 +1,336 @@
	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>
	12	#include <linux/module.h>
	13	#include <linux/pagemap.h>
	14	#include <linux/pagevec.h>
	15	#include <linux/buffer_head.h> /* grr. try_to_release_page,
	16	block_invalidatepage */
	17
	18
	19	static int do_invalidatepage(struct page *page, unsigned long offset)
	20	{
	21	int (invalidatepage)(struct page , unsigned long);
	22	invalidatepage = page->mapping->a_ops->invalidatepage;
	23	if (invalidatepage == NULL)
	24	invalidatepage = block_invalidatepage;
	25	return (*invalidatepage)(page, offset);
	26	}
	27
	28	static inline void truncate_partial_page(struct page *page, unsigned partial)
	29	{
	30	memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial);
	31	if (PagePrivate(page))
	32	do_invalidatepage(page, partial);
	33	}
	34
	35	/*
	36	* If truncate cannot remove the fs-private metadata from the page, the page
	37	* becomes anonymous. It will be left on the LRU and may even be mapped into
	38	* user pagetables if we're racing with filemap_nopage().
	39	*
	40	* We need to bale out if page->mapping is no longer equal to the original
	41	* mapping. This happens a) when the VM reclaimed the page while we waited on
	42	* its lock, b) when a concurrent invalidate_inode_pages got there first and
	43	* c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
	44	*/
	45	static void
	46	truncate_complete_page(struct address_space mapping, struct page page)
	47	{
	48	if (page->mapping != mapping)
	49	return;
	50
	51	if (PagePrivate(page))
	52	do_invalidatepage(page, 0);
	53
	54	clear_page_dirty(page);
	55	ClearPageUptodate(page);
	56	ClearPageMappedToDisk(page);
	57	remove_from_page_cache(page);
	58	page_cache_release(page); /* pagecache ref */
	59	}
	60
	61	/*
	62	* This is for invalidate_inode_pages(). That function can be called at
	63	* any time, and is not supposed to throw away dirty pages. But pages can
	64	* be marked dirty at any time too. So we re-check the dirtiness inside
	65	* ->tree_lock. That provides exclusion against the __set_page_dirty
	66	* functions.
	67	*
	68	* Returns non-zero if the page was successfully invalidated.
	69	*/
	70	static int
	71	invalidate_complete_page(struct address_space mapping, struct page page)
	72	{
	73	if (page->mapping != mapping)
	74	return 0;
	75
	76	if (PagePrivate(page) && !try_to_release_page(page, 0))
	77	return 0;
	78
	79	write_lock_irq(&mapping->tree_lock);
	80	if (PageDirty(page)) {
	81	write_unlock_irq(&mapping->tree_lock);
	82	return 0;
	83	}
	84
	85	BUG_ON(PagePrivate(page));
	86	__remove_from_page_cache(page);
	87	write_unlock_irq(&mapping->tree_lock);
	88	ClearPageUptodate(page);
	89	page_cache_release(page); /* pagecache ref */
	90	return 1;
	91	}
	92
	93	/**
	94	* truncate_inode_pages - truncate all the pages from an offset
	95	* @mapping: mapping to truncate
	96	* @lstart: offset from which to truncate
	97	*
	98	* Truncate the page cache at a set offset, removing the pages that are beyond
	99	* that offset (and zeroing out partial pages).
	100	*
	101	* Truncate takes two passes - the first pass is nonblocking. It will not
	102	* block on page locks and it will not block on writeback. The second pass
	103	* will wait. This is to prevent as much IO as possible in the affected region.
	104	* The first pass will remove most pages, so the search cost of the second pass
	105	* is low.
	106	*
	107	* When looking at page->index outside the page lock we need to be careful to
	108	* copy it into a local to avoid races (it could change at any time).
	109	*
	110	* We pass down the cache-hot hint to the page freeing code. Even if the
	111	* mapping is large, it is probably the case that the final pages are the most
	112	* recently touched, and freeing happens in ascending file offset order.
	113	*
	114	* Called under (and serialised by) inode->i_sem.
	115	*/
	116	void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
	117	{
	118	const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
	119	const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
	120	struct pagevec pvec;
	121	pgoff_t next;
	122	int i;
	123
	124	if (mapping->nrpages == 0)
	125	return;
	126
	127	pagevec_init(&pvec, 0);
	128	next = start;
	129	while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
	130	for (i = 0; i < pagevec_count(&pvec); i++) {
	131	struct page *page = pvec.pages[i];
	132	pgoff_t page_index = page->index;
	133
	134	if (page_index > next)
	135	next = page_index;
	136	next++;
	137	if (TestSetPageLocked(page))
	138	continue;
	139	if (PageWriteback(page)) {
	140	unlock_page(page);
	141	continue;
	142	}
	143	truncate_complete_page(mapping, page);
	144	unlock_page(page);
	145	}
	146	pagevec_release(&pvec);
	147	cond_resched();
	148	}
	149
	150	if (partial) {
	151	struct page *page = find_lock_page(mapping, start - 1);
	152	if (page) {
	153	wait_on_page_writeback(page);
	154	truncate_partial_page(page, partial);
	155	unlock_page(page);
	156	page_cache_release(page);
	157	}
	158	}
	159
	160	next = start;
	161	for ( ; ; ) {
	162	cond_resched();
	163	if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
	164	if (next == start)
	165	break;
	166	next = start;
	167	continue;
	168	}
	169	for (i = 0; i < pagevec_count(&pvec); i++) {
	170	struct page *page = pvec.pages[i];
	171
	172	lock_page(page);
	173	wait_on_page_writeback(page);
	174	if (page->index > next)
	175	next = page->index;
	176	next++;
	177	truncate_complete_page(mapping, page);
	178	unlock_page(page);
	179	}
	180	pagevec_release(&pvec);
	181	}
	182	}
	183
	184	EXPORT_SYMBOL(truncate_inode_pages);
	185
	186	/**
	187	* invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
	188	* @mapping: the address_space which holds the pages to invalidate
	189	* @start: the offset 'from' which to invalidate
	190	* @end: the offset 'to' which to invalidate (inclusive)
	191	*
	192	* This function only removes the unlocked pages, if you want to
	193	* remove all the pages of one inode, you must call truncate_inode_pages.
	194	*
	195	* invalidate_mapping_pages() will not block on IO activity. It will not
	196	* invalidate pages which are dirty, locked, under writeback or mapped into
	197	* pagetables.
	198	*/
	199	unsigned long invalidate_mapping_pages(struct address_space *mapping,
	200	pgoff_t start, pgoff_t end)
	201	{
	202	struct pagevec pvec;
	203	pgoff_t next = start;
	204	unsigned long ret = 0;
	205	int i;
	206
	207	pagevec_init(&pvec, 0);
	208	while (next <= end &&
	209	pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
	210	for (i = 0; i < pagevec_count(&pvec); i++) {
	211	struct page *page = pvec.pages[i];
	212
	213	if (TestSetPageLocked(page)) {
	214	next++;
	215	continue;
	216	}
	217	if (page->index > next)
	218	next = page->index;
	219	next++;
	220	if (PageDirty(page) \|\| PageWriteback(page))
	221	goto unlock;
	222	if (page_mapped(page))
	223	goto unlock;
	224	ret += invalidate_complete_page(mapping, page);
	225	unlock:
	226	unlock_page(page);
	227	if (next > end)
	228	break;
	229	}
	230	pagevec_release(&pvec);
	231	cond_resched();
	232	}
	233	return ret;
	234	}
	235
	236	unsigned long invalidate_inode_pages(struct address_space *mapping)
	237	{
	238	return invalidate_mapping_pages(mapping, 0, ~0UL);
	239	}
	240
	241	EXPORT_SYMBOL(invalidate_inode_pages);
	242
	243	/**
	244	* invalidate_inode_pages2_range - remove range of pages from an address_space
	245	* @mapping - the address_space
	246	* @start: the page offset 'from' which to invalidate
	247	* @end: the page offset 'to' which to invalidate (inclusive)
	248	*
	249	* Any pages which are found to be mapped into pagetables are unmapped prior to
	250	* invalidation.
	251	*
	252	* Returns -EIO if any pages could not be invalidated.
	253	*/
	254	int invalidate_inode_pages2_range(struct address_space *mapping,
	255	pgoff_t start, pgoff_t end)
	256	{
	257	struct pagevec pvec;
	258	pgoff_t next;
	259	int i;
	260	int ret = 0;
	261	int did_range_unmap = 0;
	262	int wrapped = 0;
	263
	264	pagevec_init(&pvec, 0);
	265	next = start;
	266	while (next <= end && !ret && !wrapped &&
	267	pagevec_lookup(&pvec, mapping, next,
	268	min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
	269	for (i = 0; !ret && i < pagevec_count(&pvec); i++) {
	270	struct page *page = pvec.pages[i];
	271	pgoff_t page_index;
	272	int was_dirty;
	273
	274	lock_page(page);
	275	if (page->mapping != mapping) {
	276	unlock_page(page);
	277	continue;
	278	}
	279	page_index = page->index;
	280	next = page_index + 1;
	281	if (next == 0)
	282	wrapped = 1;
	283	if (page_index > end) {
	284	unlock_page(page);
	285	break;
	286	}
	287	wait_on_page_writeback(page);
	288	while (page_mapped(page)) {
	289	if (!did_range_unmap) {
	290	/*
	291	* Zap the rest of the file in one hit.
	292	*/
	293	unmap_mapping_range(mapping,
	294	page_index << PAGE_CACHE_SHIFT,
	295	(end - page_index + 1)
	296	<< PAGE_CACHE_SHIFT,
	297	0);
	298	did_range_unmap = 1;
	299	} else {
	300	/*
	301	* Just zap this page
	302	*/
	303	unmap_mapping_range(mapping,
	304	page_index << PAGE_CACHE_SHIFT,
	305	PAGE_CACHE_SIZE, 0);
	306	}
	307	}
	308	was_dirty = test_clear_page_dirty(page);
	309	if (!invalidate_complete_page(mapping, page)) {
	310	if (was_dirty)
	311	set_page_dirty(page);
	312	ret = -EIO;
	313	}
	314	unlock_page(page);
	315	}
	316	pagevec_release(&pvec);
	317	cond_resched();
	318	}
	319	return ret;
	320	}
	321	EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
	322
	323	/**
	324	* invalidate_inode_pages2 - remove all pages from an address_space
	325	* @mapping - the address_space
	326	*
	327	* Any pages which are found to be mapped into pagetables are unmapped prior to
	328	* invalidation.
	329	*
	330	* Returns -EIO if any pages could not be invalidated.
	331	*/
	332	int invalidate_inode_pages2(struct address_space *mapping)
	333	{
	334	return invalidate_inode_pages2_range(mapping, 0, -1);
	335	}
	336	EXPORT_SYMBOL_GPL(invalidate_inode_pages2);