[linux.git] / fs / nilfs2 / page.c

/*
 * page.c - buffer/page management specific to NILFS
 *
 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Written by Ryusuke Konishi <[email protected]>,
 *            Seiji Kihara <[email protected]>.
 */

#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/bitops.h>
#include <linux/page-flags.h>
#include <linux/list.h>
#include <linux/highmem.h>
#include <linux/pagevec.h>
#include <linux/gfp.h>
#include "nilfs.h"
#include "page.h"
#include "mdt.h"


#define NILFS_BUFFER_INHERENT_BITS  \
	((1UL << BH_Uptodate) | (1UL << BH_Mapped) | (1UL << BH_NILFS_Node) | \
	 (1UL << BH_NILFS_Volatile) | (1UL << BH_NILFS_Checked))

static struct buffer_head *
__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
		       int blkbits, unsigned long b_state)

{
	unsigned long first_block;
	struct buffer_head *bh;

	if (!page_has_buffers(page))
		create_empty_buffers(page, 1 << blkbits, b_state);

	first_block = (unsigned long)index << (PAGE_CACHE_SHIFT - blkbits);
	bh = nilfs_page_get_nth_block(page, block - first_block);

	touch_buffer(bh);
	wait_on_buffer(bh);
	return bh;
}

struct buffer_head *nilfs_grab_buffer(struct inode *inode,
				      struct address_space *mapping,
				      unsigned long blkoff,
				      unsigned long b_state)
{
	int blkbits = inode->i_blkbits;
	pgoff_t index = blkoff >> (PAGE_CACHE_SHIFT - blkbits);
	struct page *page;
	struct buffer_head *bh;

	page = grab_cache_page(mapping, index);
	if (unlikely(!page))
		return NULL;

	bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
	if (unlikely(!bh)) {
		unlock_page(page);
		page_cache_release(page);
		return NULL;
	}
	return bh;
}

/**
 * nilfs_forget_buffer - discard dirty state
 * @inode: owner inode of the buffer
 * @bh: buffer head of the buffer to be discarded
 */
void nilfs_forget_buffer(struct buffer_head *bh)
{
	struct page *page = bh->b_page;

	lock_buffer(bh);
	clear_buffer_nilfs_volatile(bh);
	clear_buffer_nilfs_checked(bh);
	clear_buffer_nilfs_redirected(bh);
	clear_buffer_dirty(bh);
	if (nilfs_page_buffers_clean(page))
		__nilfs_clear_page_dirty(page);

	clear_buffer_uptodate(bh);
	clear_buffer_mapped(bh);
	bh->b_blocknr = -1;
	ClearPageUptodate(page);
	ClearPageMappedToDisk(page);
	unlock_buffer(bh);
	brelse(bh);
}

/**
 * nilfs_copy_buffer -- copy buffer data and flags
 * @dbh: destination buffer
 * @sbh: source buffer
 */
void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
{
	void *kaddr0, *kaddr1;
	unsigned long bits;
	struct page *spage = sbh->b_page, *dpage = dbh->b_page;
	struct buffer_head *bh;

	kaddr0 = kmap_atomic(spage);
	kaddr1 = kmap_atomic(dpage);
	memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
	kunmap_atomic(kaddr1);
	kunmap_atomic(kaddr0);

	dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
	dbh->b_blocknr = sbh->b_blocknr;
	dbh->b_bdev = sbh->b_bdev;

	bh = dbh;
	bits = sbh->b_state & ((1UL << BH_Uptodate) | (1UL << BH_Mapped));
	while ((bh = bh->b_this_page) != dbh) {
		lock_buffer(bh);
		bits &= bh->b_state;
		unlock_buffer(bh);
	}
	if (bits & (1UL << BH_Uptodate))
		SetPageUptodate(dpage);
	else
		ClearPageUptodate(dpage);
	if (bits & (1UL << BH_Mapped))
		SetPageMappedToDisk(dpage);
	else
		ClearPageMappedToDisk(dpage);
}

/**
 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
 * @page: page to be checked
 *
 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
 * Otherwise, it returns non-zero value.
 */
int nilfs_page_buffers_clean(struct page *page)
{
	struct buffer_head *bh, *head;

	bh = head = page_buffers(page);
	do {
		if (buffer_dirty(bh))
			return 0;
		bh = bh->b_this_page;
	} while (bh != head);
	return 1;
}

void nilfs_page_bug(struct page *page)
{
	struct address_space *m;
	unsigned long ino;

	if (unlikely(!page)) {
		printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
		return;
	}

	m = page->mapping;
	ino = m ? m->host->i_ino : 0;

	printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
	       "mapping=%p ino=%lu\n",
	       page, atomic_read(&page->_count),
	       (unsigned long long)page->index, page->flags, m, ino);

	if (page_has_buffers(page)) {
		struct buffer_head *bh, *head;
		int i = 0;

		bh = head = page_buffers(page);
		do {
			printk(KERN_CRIT
			       " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
			       i++, bh, atomic_read(&bh->b_count),
			       (unsigned long long)bh->b_blocknr, bh->b_state);
			bh = bh->b_this_page;
		} while (bh != head);
	}
}

/**
 * nilfs_copy_page -- copy the page with buffers
 * @dst: destination page
 * @src: source page
 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
 *
 * This function is for both data pages and btnode pages.  The dirty flag
 * should be treated by caller.  The page must not be under i/o.
 * Both src and dst page must be locked
 */
static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
{
	struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
	unsigned long mask = NILFS_BUFFER_INHERENT_BITS;

	BUG_ON(PageWriteback(dst));

	sbh = sbufs = page_buffers(src);
	if (!page_has_buffers(dst))
		create_empty_buffers(dst, sbh->b_size, 0);

	if (copy_dirty)
		mask |= (1UL << BH_Dirty);

	dbh = dbufs = page_buffers(dst);
	do {
		lock_buffer(sbh);
		lock_buffer(dbh);
		dbh->b_state = sbh->b_state & mask;
		dbh->b_blocknr = sbh->b_blocknr;
		dbh->b_bdev = sbh->b_bdev;
		sbh = sbh->b_this_page;
		dbh = dbh->b_this_page;
	} while (dbh != dbufs);

	copy_highpage(dst, src);

	if (PageUptodate(src) && !PageUptodate(dst))
		SetPageUptodate(dst);
	else if (!PageUptodate(src) && PageUptodate(dst))
		ClearPageUptodate(dst);
	if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
		SetPageMappedToDisk(dst);
	else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
		ClearPageMappedToDisk(dst);

	do {
		unlock_buffer(sbh);
		unlock_buffer(dbh);
		sbh = sbh->b_this_page;
		dbh = dbh->b_this_page;
	} while (dbh != dbufs);
}

int nilfs_copy_dirty_pages(struct address_space *dmap,
			   struct address_space *smap)
{
	struct pagevec pvec;
	unsigned int i;
	pgoff_t index = 0;
	int err = 0;

	pagevec_init(&pvec, 0);
repeat:
	if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY,
				PAGEVEC_SIZE))
		return 0;

	for (i = 0; i < pagevec_count(&pvec); i++) {
		struct page *page = pvec.pages[i], *dpage;

		lock_page(page);
		if (unlikely(!PageDirty(page)))
			NILFS_PAGE_BUG(page, "inconsistent dirty state");

		dpage = grab_cache_page(dmap, page->index);
		if (unlikely(!dpage)) {
			/* No empty page is added to the page cache */
			err = -ENOMEM;
			unlock_page(page);
			break;
		}
		if (unlikely(!page_has_buffers(page)))
			NILFS_PAGE_BUG(page,
				       "found empty page in dat page cache");

		nilfs_copy_page(dpage, page, 1);
		__set_page_dirty_nobuffers(dpage);

		unlock_page(dpage);
		page_cache_release(dpage);
		unlock_page(page);
	}
	pagevec_release(&pvec);
	cond_resched();

	if (likely(!err))
		goto repeat;
	return err;
}

/**
 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
 * @dmap: destination page cache
 * @smap: source page cache
 *
 * No pages must no be added to the cache during this process.
 * This must be ensured by the caller.
 */
void nilfs_copy_back_pages(struct address_space *dmap,
			   struct address_space *smap)
{
	struct pagevec pvec;
	unsigned int i, n;
	pgoff_t index = 0;
	int err;

	pagevec_init(&pvec, 0);
repeat:
	n = pagevec_lookup(&pvec, smap, index, PAGEVEC_SIZE);
	if (!n)
		return;
	index = pvec.pages[n - 1]->index + 1;

	for (i = 0; i < pagevec_count(&pvec); i++) {
		struct page *page = pvec.pages[i], *dpage;
		pgoff_t offset = page->index;

		lock_page(page);
		dpage = find_lock_page(dmap, offset);
		if (dpage) {
			/* override existing page on the destination cache */
			WARN_ON(PageDirty(dpage));
			nilfs_copy_page(dpage, page, 0);
			unlock_page(dpage);
			page_cache_release(dpage);
		} else {
			struct page *page2;

			/* move the page to the destination cache */
			spin_lock_irq(&smap->tree_lock);
			page2 = radix_tree_delete(&smap->page_tree, offset);
			WARN_ON(page2 != page);

			smap->nrpages--;
			spin_unlock_irq(&smap->tree_lock);

			spin_lock_irq(&dmap->tree_lock);
			err = radix_tree_insert(&dmap->page_tree, offset, page);
			if (unlikely(err < 0)) {
				WARN_ON(err == -EEXIST);
				page->mapping = NULL;
				page_cache_release(page); /* for cache */
			} else {
				page->mapping = dmap;
				dmap->nrpages++;
				if (PageDirty(page))
					radix_tree_tag_set(&dmap->page_tree,
							   offset,
							   PAGECACHE_TAG_DIRTY);
			}
			spin_unlock_irq(&dmap->tree_lock);
		}
		unlock_page(page);
	}
	pagevec_release(&pvec);
	cond_resched();

	goto repeat;
}

void nilfs_clear_dirty_pages(struct address_space *mapping)
{
	struct pagevec pvec;
	unsigned int i;
	pgoff_t index = 0;

	pagevec_init(&pvec, 0);

	while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
				  PAGEVEC_SIZE)) {
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];
			struct buffer_head *bh, *head;

			lock_page(page);
			ClearPageUptodate(page);
			ClearPageMappedToDisk(page);
			bh = head = page_buffers(page);
			do {
				lock_buffer(bh);
				clear_buffer_dirty(bh);
				clear_buffer_nilfs_volatile(bh);
				clear_buffer_nilfs_checked(bh);
				clear_buffer_nilfs_redirected(bh);
				clear_buffer_uptodate(bh);
				clear_buffer_mapped(bh);
				unlock_buffer(bh);
				bh = bh->b_this_page;
			} while (bh != head);

			__nilfs_clear_page_dirty(page);
			unlock_page(page);
		}
		pagevec_release(&pvec);
		cond_resched();
	}
}

unsigned nilfs_page_count_clean_buffers(struct page *page,
					unsigned from, unsigned to)
{
	unsigned block_start, block_end;
	struct buffer_head *bh, *head;
	unsigned nc = 0;

	for (bh = head = page_buffers(page), block_start = 0;
	     bh != head || !block_start;
	     block_start = block_end, bh = bh->b_this_page) {
		block_end = block_start + bh->b_size;
		if (block_end > from && block_start < to && !buffer_dirty(bh))
			nc++;
	}
	return nc;
}

void nilfs_mapping_init(struct address_space *mapping, struct inode *inode,
			struct backing_dev_info *bdi)
{
	mapping->host = inode;
	mapping->flags = 0;
	mapping_set_gfp_mask(mapping, GFP_NOFS);
	mapping->assoc_mapping = NULL;
	mapping->backing_dev_info = bdi;
	mapping->a_ops = &empty_aops;
}

/*
 * NILFS2 needs clear_page_dirty() in the following two cases:
 *
 * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
 *    page dirty flags when it copies back pages from the shadow cache
 *    (gcdat->{i_mapping,i_btnode_cache}) to its original cache
 *    (dat->{i_mapping,i_btnode_cache}).
 *
 * 2) Some B-tree operations like insertion or deletion may dispose buffers
 *    in dirty state, and this needs to cancel the dirty state of their pages.
 */
int __nilfs_clear_page_dirty(struct page *page)
{
	struct address_space *mapping = page->mapping;

	if (mapping) {
		spin_lock_irq(&mapping->tree_lock);
		if (test_bit(PG_dirty, &page->flags)) {
			radix_tree_tag_clear(&mapping->page_tree,
					     page_index(page),
					     PAGECACHE_TAG_DIRTY);
			spin_unlock_irq(&mapping->tree_lock);
			return clear_page_dirty_for_io(page);
		}
		spin_unlock_irq(&mapping->tree_lock);
		return 0;
	}
	return TestClearPageDirty(page);
}

/**
 * nilfs_find_uncommitted_extent - find extent of uncommitted data
 * @inode: inode
 * @start_blk: start block offset (in)
 * @blkoff: start offset of the found extent (out)
 *
 * This function searches an extent of buffers marked "delayed" which
 * starts from a block offset equal to or larger than @start_blk.  If
 * such an extent was found, this will store the start offset in
 * @blkoff and return its length in blocks.  Otherwise, zero is
 * returned.
 */
unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
					    sector_t start_blk,
					    sector_t *blkoff)
{
	unsigned int i;
	pgoff_t index;
	unsigned int nblocks_in_page;
	unsigned long length = 0;
	sector_t b;
	struct pagevec pvec;
	struct page *page;

	if (inode->i_mapping->nrpages == 0)
		return 0;

	index = start_blk >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
	nblocks_in_page = 1U << (PAGE_CACHE_SHIFT - inode->i_blkbits);

	pagevec_init(&pvec, 0);

repeat:
	pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
					pvec.pages);
	if (pvec.nr == 0)
		return length;

	if (length > 0 && pvec.pages[0]->index > index)
		goto out;

	b = pvec.pages[0]->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
	i = 0;
	do {
		page = pvec.pages[i];

		lock_page(page);
		if (page_has_buffers(page)) {
			struct buffer_head *bh, *head;

			bh = head = page_buffers(page);
			do {
				if (b < start_blk)
					continue;
				if (buffer_delay(bh)) {
					if (length == 0)
						*blkoff = b;
					length++;
				} else if (length > 0) {
					goto out_locked;
				}
			} while (++b, bh = bh->b_this_page, bh != head);
		} else {
			if (length > 0)
				goto out_locked;

			b += nblocks_in_page;
		}
		unlock_page(page);

	} while (++i < pagevec_count(&pvec));

	index = page->index + 1;
	pagevec_release(&pvec);
	cond_resched();
	goto repeat;

out_locked:
	unlock_page(page);
out:
	pagevec_release(&pvec);
	return length;
}
Commit	Line	Data
0bd49f94 RK	1	/*
	2	* page.c - buffer/page management specific to NILFS
	3	*
	4	* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	19	*
	20	* Written by Ryusuke Konishi <[email protected]>,
	21	* Seiji Kihara <[email protected]>.
	22	*/
	23
	24	#include <linux/pagemap.h>
	25	#include <linux/writeback.h>
	26	#include <linux/swap.h>
	27	#include <linux/bitops.h>
	28	#include <linux/page-flags.h>
	29	#include <linux/list.h>
	30	#include <linux/highmem.h>
	31	#include <linux/pagevec.h>
5a0e3ad6	32	#include <linux/gfp.h>
0bd49f94 RK	33	#include "nilfs.h"
	34	#include "page.h"
	35	#include "mdt.h"
	36
	37
	38	#define NILFS_BUFFER_INHERENT_BITS \
	39	((1UL << BH_Uptodate) \| (1UL << BH_Mapped) \| (1UL << BH_NILFS_Node) \| \
1cb2d38c	40	(1UL << BH_NILFS_Volatile) \| (1UL << BH_NILFS_Checked))
0bd49f94 RK	41
	42	static struct buffer_head *
	43	__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
	44	int blkbits, unsigned long b_state)
	45
	46	{
	47	unsigned long first_block;
	48	struct buffer_head *bh;
	49
	50	if (!page_has_buffers(page))
	51	create_empty_buffers(page, 1 << blkbits, b_state);
	52
	53	first_block = (unsigned long)index << (PAGE_CACHE_SHIFT - blkbits);
	54	bh = nilfs_page_get_nth_block(page, block - first_block);
	55
	56	touch_buffer(bh);
	57	wait_on_buffer(bh);
	58	return bh;
	59	}
	60
0bd49f94 RK	61	struct buffer_head nilfs_grab_buffer(struct inode inode,
	62	struct address_space *mapping,
	63	unsigned long blkoff,
	64	unsigned long b_state)
	65	{
	66	int blkbits = inode->i_blkbits;
	67	pgoff_t index = blkoff >> (PAGE_CACHE_SHIFT - blkbits);
c1c1d709 RK	68	struct page *page;
c1c1d709 RK	69	struct buffer_head *bh;
0bd49f94 RK	70
	71	page = grab_cache_page(mapping, index);
	72	if (unlikely(!page))
	73	return NULL;
	74
	75	bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
	76	if (unlikely(!bh)) {
	77	unlock_page(page);
	78	page_cache_release(page);
	79	return NULL;
	80	}
0bd49f94 RK	81	return bh;
	82	}
	83
	84	/**
	85	* nilfs_forget_buffer - discard dirty state
	86	* @inode: owner inode of the buffer
	87	* @bh: buffer head of the buffer to be discarded
	88	*/
	89	void nilfs_forget_buffer(struct buffer_head *bh)
	90	{
	91	struct page *page = bh->b_page;
	92
	93	lock_buffer(bh);
	94	clear_buffer_nilfs_volatile(bh);
4e13e66b	95	clear_buffer_nilfs_checked(bh);
b1f6a4f2	96	clear_buffer_nilfs_redirected(bh);
84338237 RK	97	clear_buffer_dirty(bh);
84338237 RK	98	if (nilfs_page_buffers_clean(page))
0bd49f94 RK	99	__nilfs_clear_page_dirty(page);
	100
	101	clear_buffer_uptodate(bh);
	102	clear_buffer_mapped(bh);
	103	bh->b_blocknr = -1;
	104	ClearPageUptodate(page);
	105	ClearPageMappedToDisk(page);
	106	unlock_buffer(bh);
	107	brelse(bh);
	108	}
	109
	110	/**
	111	* nilfs_copy_buffer -- copy buffer data and flags
	112	* @dbh: destination buffer
	113	* @sbh: source buffer
	114	*/
	115	void nilfs_copy_buffer(struct buffer_head dbh, struct buffer_head sbh)
	116	{
	117	void kaddr0, kaddr1;
	118	unsigned long bits;
	119	struct page spage = sbh->b_page, dpage = dbh->b_page;
	120	struct buffer_head *bh;
	121
7b9c0976 CW	122	kaddr0 = kmap_atomic(spage);
7b9c0976 CW	123	kaddr1 = kmap_atomic(dpage);
0bd49f94	124	memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
7b9c0976 CW	125	kunmap_atomic(kaddr1);
7b9c0976 CW	126	kunmap_atomic(kaddr0);
0bd49f94 RK	127
	128	dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
	129	dbh->b_blocknr = sbh->b_blocknr;
	130	dbh->b_bdev = sbh->b_bdev;
	131
	132	bh = dbh;
	133	bits = sbh->b_state & ((1UL << BH_Uptodate) \| (1UL << BH_Mapped));
	134	while ((bh = bh->b_this_page) != dbh) {
	135	lock_buffer(bh);
	136	bits &= bh->b_state;
	137	unlock_buffer(bh);
	138	}
	139	if (bits & (1UL << BH_Uptodate))
	140	SetPageUptodate(dpage);
	141	else
	142	ClearPageUptodate(dpage);
	143	if (bits & (1UL << BH_Mapped))
	144	SetPageMappedToDisk(dpage);
	145	else
	146	ClearPageMappedToDisk(dpage);
	147	}
	148
	149	/**
	150	* nilfs_page_buffers_clean - check if a page has dirty buffers or not.
	151	* @page: page to be checked
	152	*
	153	* nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
	154	* Otherwise, it returns non-zero value.
	155	*/
	156	int nilfs_page_buffers_clean(struct page *page)
	157	{
	158	struct buffer_head bh, head;
	159
	160	bh = head = page_buffers(page);
	161	do {
	162	if (buffer_dirty(bh))
	163	return 0;
	164	bh = bh->b_this_page;
	165	} while (bh != head);
	166	return 1;
	167	}
	168
	169	void nilfs_page_bug(struct page *page)
	170	{
	171	struct address_space *m;
aa405b1f	172	unsigned long ino;
0bd49f94 RK	173
	174	if (unlikely(!page)) {
	175	printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
	176	return;
	177	}
	178
	179	m = page->mapping;
aa405b1f RK	180	ino = m ? m->host->i_ino : 0;
aa405b1f RK	181
0bd49f94 RK	182	printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
	183	"mapping=%p ino=%lu\n",
	184	page, atomic_read(&page->_count),
	185	(unsigned long long)page->index, page->flags, m, ino);
	186
	187	if (page_has_buffers(page)) {
	188	struct buffer_head bh, head;
	189	int i = 0;
	190
	191	bh = head = page_buffers(page);
	192	do {
	193	printk(KERN_CRIT
	194	" BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
	195	i++, bh, atomic_read(&bh->b_count),
	196	(unsigned long long)bh->b_blocknr, bh->b_state);
	197	bh = bh->b_this_page;
	198	} while (bh != head);
	199	}
	200	}
	201
0bd49f94 RK	202	/**
	203	* nilfs_copy_page -- copy the page with buffers
	204	* @dst: destination page
	205	* @src: source page
	206	* @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
	207	*
7a65004b	208	* This function is for both data pages and btnode pages. The dirty flag
0bd49f94 RK	209	* should be treated by caller. The page must not be under i/o.
	210	* Both src and dst page must be locked
	211	*/
	212	static void nilfs_copy_page(struct page dst, struct page src, int copy_dirty)
	213	{
	214	struct buffer_head dbh, dbufs, sbh, sbufs;
	215	unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
	216
	217	BUG_ON(PageWriteback(dst));
	218
	219	sbh = sbufs = page_buffers(src);
	220	if (!page_has_buffers(dst))
	221	create_empty_buffers(dst, sbh->b_size, 0);
	222
	223	if (copy_dirty)
	224	mask \|= (1UL << BH_Dirty);
	225
	226	dbh = dbufs = page_buffers(dst);
	227	do {
	228	lock_buffer(sbh);
	229	lock_buffer(dbh);
	230	dbh->b_state = sbh->b_state & mask;
	231	dbh->b_blocknr = sbh->b_blocknr;
	232	dbh->b_bdev = sbh->b_bdev;
	233	sbh = sbh->b_this_page;
	234	dbh = dbh->b_this_page;
	235	} while (dbh != dbufs);
	236
	237	copy_highpage(dst, src);
	238
	239	if (PageUptodate(src) && !PageUptodate(dst))
	240	SetPageUptodate(dst);
	241	else if (!PageUptodate(src) && PageUptodate(dst))
	242	ClearPageUptodate(dst);
	243	if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
	244	SetPageMappedToDisk(dst);
	245	else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
	246	ClearPageMappedToDisk(dst);
	247
	248	do {
	249	unlock_buffer(sbh);
	250	unlock_buffer(dbh);
	251	sbh = sbh->b_this_page;
	252	dbh = dbh->b_this_page;
	253	} while (dbh != dbufs);
	254	}
	255
	256	int nilfs_copy_dirty_pages(struct address_space *dmap,
	257	struct address_space *smap)
	258	{
	259	struct pagevec pvec;
	260	unsigned int i;
	261	pgoff_t index = 0;
	262	int err = 0;
	263
	264	pagevec_init(&pvec, 0);
	265	repeat:
	266	if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY,
	267	PAGEVEC_SIZE))
	268	return 0;
	269
	270	for (i = 0; i < pagevec_count(&pvec); i++) {
	271	struct page page = pvec.pages[i], dpage;
	272
273	lock_page(page);
274	if (unlikely(!PageDirty(page)))
275	NILFS_PAGE_BUG(page, "inconsistent dirty state");
276
277	dpage = grab_cache_page(dmap, page->index);
278	if (unlikely(!dpage)) {
279	/* No empty page is added to the page cache */
280	err = -ENOMEM;
281	unlock_page(page);
282	break;
283	}
284	if (unlikely(!page_has_buffers(page)))
285	NILFS_PAGE_BUG(page,
286	"found empty page in dat page cache");
287
288	nilfs_copy_page(dpage, page, 1);
289	__set_page_dirty_nobuffers(dpage);
290
291	unlock_page(dpage);
292	page_cache_release(dpage);
293	unlock_page(page);
294	}
295	pagevec_release(&pvec);
296	cond_resched();
297
298	if (likely(!err))
299	goto repeat;
300	return err;
301	}
302
303	/**
7a65004b	304	* nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
0bd49f94 RK	305	* @dmap: destination page cache
	306	* @smap: source page cache
	307	*
	308	* No pages must no be added to the cache during this process.
	309	* This must be ensured by the caller.
	310	*/
	311	void nilfs_copy_back_pages(struct address_space *dmap,
	312	struct address_space *smap)
	313	{
	314	struct pagevec pvec;
	315	unsigned int i, n;
	316	pgoff_t index = 0;
	317	int err;
	318
	319	pagevec_init(&pvec, 0);
	320	repeat:
	321	n = pagevec_lookup(&pvec, smap, index, PAGEVEC_SIZE);
	322	if (!n)
	323	return;
	324	index = pvec.pages[n - 1]->index + 1;
	325
	326	for (i = 0; i < pagevec_count(&pvec); i++) {
	327	struct page page = pvec.pages[i], dpage;
	328	pgoff_t offset = page->index;
	329
	330	lock_page(page);
	331	dpage = find_lock_page(dmap, offset);
	332	if (dpage) {
	333	/* override existing page on the destination cache */
1f5abe7e	334	WARN_ON(PageDirty(dpage));
0bd49f94 RK	335	nilfs_copy_page(dpage, page, 0);
	336	unlock_page(dpage);
	337	page_cache_release(dpage);
	338	} else {
	339	struct page *page2;
	340
	341	/* move the page to the destination cache */
	342	spin_lock_irq(&smap->tree_lock);
	343	page2 = radix_tree_delete(&smap->page_tree, offset);
1f5abe7e RK	344	WARN_ON(page2 != page);
1f5abe7e RK	345
0bd49f94 RK	346	smap->nrpages--;
	347	spin_unlock_irq(&smap->tree_lock);
	348
	349	spin_lock_irq(&dmap->tree_lock);
	350	err = radix_tree_insert(&dmap->page_tree, offset, page);
	351	if (unlikely(err < 0)) {
1f5abe7e	352	WARN_ON(err == -EEXIST);
0bd49f94 RK	353	page->mapping = NULL;
	354	page_cache_release(page); /* for cache */
	355	} else {
	356	page->mapping = dmap;
	357	dmap->nrpages++;
	358	if (PageDirty(page))
	359	radix_tree_tag_set(&dmap->page_tree,
	360	offset,
	361	PAGECACHE_TAG_DIRTY);
	362	}
	363	spin_unlock_irq(&dmap->tree_lock);
	364	}
	365	unlock_page(page);
	366	}
	367	pagevec_release(&pvec);
	368	cond_resched();
	369
	370	goto repeat;
	371	}
	372
	373	void nilfs_clear_dirty_pages(struct address_space *mapping)
	374	{
	375	struct pagevec pvec;
	376	unsigned int i;
	377	pgoff_t index = 0;
	378
	379	pagevec_init(&pvec, 0);
	380
	381	while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
	382	PAGEVEC_SIZE)) {
	383	for (i = 0; i < pagevec_count(&pvec); i++) {
	384	struct page *page = pvec.pages[i];
	385	struct buffer_head bh, head;
	386
	387	lock_page(page);
	388	ClearPageUptodate(page);
	389	ClearPageMappedToDisk(page);
	390	bh = head = page_buffers(page);
	391	do {
	392	lock_buffer(bh);
	393	clear_buffer_dirty(bh);
	394	clear_buffer_nilfs_volatile(bh);
4e13e66b	395	clear_buffer_nilfs_checked(bh);
b1f6a4f2	396	clear_buffer_nilfs_redirected(bh);
0bd49f94 RK	397	clear_buffer_uptodate(bh);
	398	clear_buffer_mapped(bh);
	399	unlock_buffer(bh);
	400	bh = bh->b_this_page;
	401	} while (bh != head);
	402
	403	__nilfs_clear_page_dirty(page);
	404	unlock_page(page);
	405	}
	406	pagevec_release(&pvec);
	407	cond_resched();
	408	}
	409	}
	410
	411	unsigned nilfs_page_count_clean_buffers(struct page *page,
	412	unsigned from, unsigned to)
	413	{
	414	unsigned block_start, block_end;
	415	struct buffer_head bh, head;
	416	unsigned nc = 0;
	417
	418	for (bh = head = page_buffers(page), block_start = 0;
	419	bh != head \|\| !block_start;
	420	block_start = block_end, bh = bh->b_this_page) {
	421	block_end = block_start + bh->b_size;
	422	if (block_end > from && block_start < to && !buffer_dirty(bh))
	423	nc++;
	424	}
	425	return nc;
	426	}
ae53a0a2	427
aa405b1f	428	void nilfs_mapping_init(struct address_space mapping, struct inode inode,
7eaceacc	429	struct backing_dev_info *bdi)
ebdfed4d	430	{
aa405b1f	431	mapping->host = inode;
ebdfed4d RK	432	mapping->flags = 0;
	433	mapping_set_gfp_mask(mapping, GFP_NOFS);
	434	mapping->assoc_mapping = NULL;
	435	mapping->backing_dev_info = bdi;
d611b22f	436	mapping->a_ops = &empty_aops;
ebdfed4d	437	}
0bd49f94 RK	438
	439	/*
	440	* NILFS2 needs clear_page_dirty() in the following two cases:
	441	*
	442	* 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
	443	* page dirty flags when it copies back pages from the shadow cache
	444	* (gcdat->{i_mapping,i_btnode_cache}) to its original cache
	445	* (dat->{i_mapping,i_btnode_cache}).
	446	*
	447	* 2) Some B-tree operations like insertion or deletion may dispose buffers
	448	* in dirty state, and this needs to cancel the dirty state of their pages.
	449	*/
	450	int __nilfs_clear_page_dirty(struct page *page)
	451	{
	452	struct address_space *mapping = page->mapping;
	453
	454	if (mapping) {
	455	spin_lock_irq(&mapping->tree_lock);
	456	if (test_bit(PG_dirty, &page->flags)) {
	457	radix_tree_tag_clear(&mapping->page_tree,
	458	page_index(page),
	459	PAGECACHE_TAG_DIRTY);
	460	spin_unlock_irq(&mapping->tree_lock);
	461	return clear_page_dirty_for_io(page);
	462	}
	463	spin_unlock_irq(&mapping->tree_lock);
	464	return 0;
	465	}
	466	return TestClearPageDirty(page);
	467	}
622daaff RK	468
	469	/**
	470	* nilfs_find_uncommitted_extent - find extent of uncommitted data
	471	* @inode: inode
	472	* @start_blk: start block offset (in)
	473	* @blkoff: start offset of the found extent (out)
	474	*
	475	* This function searches an extent of buffers marked "delayed" which
	476	* starts from a block offset equal to or larger than @start_blk. If
	477	* such an extent was found, this will store the start offset in
	478	* @blkoff and return its length in blocks. Otherwise, zero is
	479	* returned.
	480	*/
	481	unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
	482	sector_t start_blk,
	483	sector_t *blkoff)
	484	{
	485	unsigned int i;
	486	pgoff_t index;
	487	unsigned int nblocks_in_page;
	488	unsigned long length = 0;
	489	sector_t b;
	490	struct pagevec pvec;
	491	struct page *page;
	492
	493	if (inode->i_mapping->nrpages == 0)
	494	return 0;
	495
	496	index = start_blk >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
	497	nblocks_in_page = 1U << (PAGE_CACHE_SHIFT - inode->i_blkbits);
	498
	499	pagevec_init(&pvec, 0);
	500
	501	repeat:
	502	pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
	503	pvec.pages);
	504	if (pvec.nr == 0)
	505	return length;
	506
	507	if (length > 0 && pvec.pages[0]->index > index)
	508	goto out;
	509
	510	b = pvec.pages[0]->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
	511	i = 0;
	512	do {
	513	page = pvec.pages[i];
	514
	515	lock_page(page);
	516	if (page_has_buffers(page)) {
	517	struct buffer_head bh, head;
	518
	519	bh = head = page_buffers(page);
	520	do {
	521	if (b < start_blk)
	522	continue;
	523	if (buffer_delay(bh)) {
	524	if (length == 0)
	525	*blkoff = b;
	526	length++;
	527	} else if (length > 0) {
	528	goto out_locked;
	529	}
	530	} while (++b, bh = bh->b_this_page, bh != head);
	531	} else {
532	if (length > 0)
533	goto out_locked;
534
535	b += nblocks_in_page;
536	}
537	unlock_page(page);
538
539	} while (++i < pagevec_count(&pvec));
540
541	index = page->index + 1;
542	pagevec_release(&pvec);
543	cond_resched();
544	goto repeat;
545
546	out_locked:
547	unlock_page(page);
548	out:
549	pagevec_release(&pvec);
550	return length;
551	}