xfs_aops.c 35.7 KB
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/*
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 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
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 *
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 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
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 * published by the Free Software Foundation.
 *
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 * This program is distributed in the hope that it would 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.
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 *
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 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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 */
#include "xfs.h"
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#include "xfs_bit.h"
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#include "xfs_log.h"
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#include "xfs_inum.h"
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#include "xfs_sb.h"
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#include "xfs_ag.h"
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#include "xfs_dir2.h"
#include "xfs_trans.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
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#include "xfs_attr_sf.h"
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#include "xfs_dinode.h"
#include "xfs_inode.h"
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#include "xfs_alloc.h"
#include "xfs_btree.h"
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#include "xfs_error.h"
#include "xfs_rw.h"
#include "xfs_iomap.h"
#include <linux/mpage.h>
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#include <linux/pagevec.h>
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#include <linux/writeback.h>

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STATIC void
xfs_count_page_state(
	struct page		*page,
	int			*delalloc,
	int			*unmapped,
	int			*unwritten)
{
	struct buffer_head	*bh, *head;

	*delalloc = *unmapped = *unwritten = 0;

	bh = head = page_buffers(page);
	do {
		if (buffer_uptodate(bh) && !buffer_mapped(bh))
			(*unmapped) = 1;
		else if (buffer_unwritten(bh) && !buffer_delay(bh))
			clear_buffer_unwritten(bh);
		else if (buffer_unwritten(bh))
			(*unwritten) = 1;
		else if (buffer_delay(bh))
			(*delalloc) = 1;
	} while ((bh = bh->b_this_page) != head);
}

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#if defined(XFS_RW_TRACE)
void
xfs_page_trace(
	int		tag,
	struct inode	*inode,
	struct page	*page,
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	unsigned long	pgoff)
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{
	xfs_inode_t	*ip;
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	bhv_vnode_t	*vp = vn_from_inode(inode);
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	loff_t		isize = i_size_read(inode);
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	loff_t		offset = page_offset(page);
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	int		delalloc = -1, unmapped = -1, unwritten = -1;

	if (page_has_buffers(page))
		xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);

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	ip = xfs_vtoi(vp);
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	if (!ip->i_rwtrace)
		return;

	ktrace_enter(ip->i_rwtrace,
		(void *)((unsigned long)tag),
		(void *)ip,
		(void *)inode,
		(void *)page,
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		(void *)pgoff,
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		(void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
		(void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
		(void *)((unsigned long)((isize >> 32) & 0xffffffff)),
		(void *)((unsigned long)(isize & 0xffffffff)),
		(void *)((unsigned long)((offset >> 32) & 0xffffffff)),
		(void *)((unsigned long)(offset & 0xffffffff)),
		(void *)((unsigned long)delalloc),
		(void *)((unsigned long)unmapped),
		(void *)((unsigned long)unwritten),
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		(void *)((unsigned long)current_pid()),
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		(void *)NULL);
}
#else
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#define xfs_page_trace(tag, inode, page, pgoff)
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#endif

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/*
 * Schedule IO completion handling on a xfsdatad if this was
 * the final hold on this ioend.
 */
STATIC void
xfs_finish_ioend(
	xfs_ioend_t		*ioend)
{
	if (atomic_dec_and_test(&ioend->io_remaining))
		queue_work(xfsdatad_workqueue, &ioend->io_work);
}

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/*
 * We're now finished for good with this ioend structure.
 * Update the page state via the associated buffer_heads,
 * release holds on the inode and bio, and finally free
 * up memory.  Do not use the ioend after this.
 */
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STATIC void
xfs_destroy_ioend(
	xfs_ioend_t		*ioend)
{
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	struct buffer_head	*bh, *next;

	for (bh = ioend->io_buffer_head; bh; bh = next) {
		next = bh->b_private;
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		bh->b_end_io(bh, !ioend->io_error);
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	}
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	if (unlikely(ioend->io_error))
		vn_ioerror(ioend->io_vnode, ioend->io_error, __FILE__,__LINE__);
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	vn_iowake(ioend->io_vnode);
	mempool_free(ioend, xfs_ioend_pool);
}

/*
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 * Buffered IO write completion for delayed allocate extents.
 * TODO: Update ondisk isize now that we know the file data
 * has been flushed (i.e. the notorious "NULL file" problem).
 */
STATIC void
xfs_end_bio_delalloc(
	void			*data)
{
	xfs_ioend_t		*ioend = data;

	xfs_destroy_ioend(ioend);
}

/*
 * Buffered IO write completion for regular, written extents.
 */
STATIC void
xfs_end_bio_written(
	void			*data)
{
	xfs_ioend_t		*ioend = data;

	xfs_destroy_ioend(ioend);
}

/*
 * IO write completion for unwritten extents.
 *
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 * Issue transactions to convert a buffer range from unwritten
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 * to written extents.
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 */
STATIC void
xfs_end_bio_unwritten(
	void			*data)
{
	xfs_ioend_t		*ioend = data;
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	bhv_vnode_t		*vp = ioend->io_vnode;
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	xfs_off_t		offset = ioend->io_offset;
	size_t			size = ioend->io_size;

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	if (likely(!ioend->io_error))
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		bhv_vop_bmap(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL);
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	xfs_destroy_ioend(ioend);
}

/*
 * Allocate and initialise an IO completion structure.
 * We need to track unwritten extent write completion here initially.
 * We'll need to extend this for updating the ondisk inode size later
 * (vs. incore size).
 */
STATIC xfs_ioend_t *
xfs_alloc_ioend(
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	struct inode		*inode,
	unsigned int		type)
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{
	xfs_ioend_t		*ioend;

	ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS);

	/*
	 * Set the count to 1 initially, which will prevent an I/O
	 * completion callback from happening before we have started
	 * all the I/O from calling the completion routine too early.
	 */
	atomic_set(&ioend->io_remaining, 1);
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	ioend->io_error = 0;
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	ioend->io_list = NULL;
	ioend->io_type = type;
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	ioend->io_vnode = vn_from_inode(inode);
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	ioend->io_buffer_head = NULL;
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	ioend->io_buffer_tail = NULL;
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	atomic_inc(&ioend->io_vnode->v_iocount);
	ioend->io_offset = 0;
	ioend->io_size = 0;

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	if (type == IOMAP_UNWRITTEN)
		INIT_WORK(&ioend->io_work, xfs_end_bio_unwritten, ioend);
	else if (type == IOMAP_DELAY)
		INIT_WORK(&ioend->io_work, xfs_end_bio_delalloc, ioend);
	else
		INIT_WORK(&ioend->io_work, xfs_end_bio_written, ioend);
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	return ioend;
}

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STATIC int
xfs_map_blocks(
	struct inode		*inode,
	loff_t			offset,
	ssize_t			count,
	xfs_iomap_t		*mapp,
	int			flags)
{
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	bhv_vnode_t		*vp = vn_from_inode(inode);
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	int			error, nmaps = 1;

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	error = bhv_vop_bmap(vp, offset, count, flags, mapp, &nmaps);
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	if (!error && (flags & (BMAPI_WRITE|BMAPI_ALLOCATE)))
		VMODIFY(vp);
	return -error;
}

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STATIC inline int
xfs_iomap_valid(
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	xfs_iomap_t		*iomapp,
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	loff_t			offset)
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{
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	return offset >= iomapp->iomap_offset &&
		offset < iomapp->iomap_offset + iomapp->iomap_bsize;
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}

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/*
 * BIO completion handler for buffered IO.
 */
STATIC int
xfs_end_bio(
	struct bio		*bio,
	unsigned int		bytes_done,
	int			error)
{
	xfs_ioend_t		*ioend = bio->bi_private;

	if (bio->bi_size)
		return 1;

	ASSERT(atomic_read(&bio->bi_cnt) >= 1);
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	ioend->io_error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : error;
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	/* Toss bio and pass work off to an xfsdatad thread */
	bio->bi_private = NULL;
	bio->bi_end_io = NULL;
	bio_put(bio);
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	xfs_finish_ioend(ioend);
	return 0;
}

STATIC void
xfs_submit_ioend_bio(
	xfs_ioend_t	*ioend,
	struct bio	*bio)
{
	atomic_inc(&ioend->io_remaining);

	bio->bi_private = ioend;
	bio->bi_end_io = xfs_end_bio;

	submit_bio(WRITE, bio);
	ASSERT(!bio_flagged(bio, BIO_EOPNOTSUPP));
	bio_put(bio);
}

STATIC struct bio *
xfs_alloc_ioend_bio(
	struct buffer_head	*bh)
{
	struct bio		*bio;
	int			nvecs = bio_get_nr_vecs(bh->b_bdev);

	do {
		bio = bio_alloc(GFP_NOIO, nvecs);
		nvecs >>= 1;
	} while (!bio);

	ASSERT(bio->bi_private == NULL);
	bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
	bio->bi_bdev = bh->b_bdev;
	bio_get(bio);
	return bio;
}

STATIC void
xfs_start_buffer_writeback(
	struct buffer_head	*bh)
{
	ASSERT(buffer_mapped(bh));
	ASSERT(buffer_locked(bh));
	ASSERT(!buffer_delay(bh));
	ASSERT(!buffer_unwritten(bh));

	mark_buffer_async_write(bh);
	set_buffer_uptodate(bh);
	clear_buffer_dirty(bh);
}

STATIC void
xfs_start_page_writeback(
	struct page		*page,
	struct writeback_control *wbc,
	int			clear_dirty,
	int			buffers)
{
	ASSERT(PageLocked(page));
	ASSERT(!PageWriteback(page));
	set_page_writeback(page);
	if (clear_dirty)
		clear_page_dirty(page);
	unlock_page(page);
	if (!buffers) {
		end_page_writeback(page);
		wbc->pages_skipped++;	/* We didn't write this page */
	}
}

static inline int bio_add_buffer(struct bio *bio, struct buffer_head *bh)
{
	return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
}

/*
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 * Submit all of the bios for all of the ioends we have saved up, covering the
 * initial writepage page and also any probed pages.
 *
 * Because we may have multiple ioends spanning a page, we need to start
 * writeback on all the buffers before we submit them for I/O. If we mark the
 * buffers as we got, then we can end up with a page that only has buffers
 * marked async write and I/O complete on can occur before we mark the other
 * buffers async write.
 *
 * The end result of this is that we trip a bug in end_page_writeback() because
 * we call it twice for the one page as the code in end_buffer_async_write()
 * assumes that all buffers on the page are started at the same time.
 *
 * The fix is two passes across the ioend list - one to start writeback on the
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 * buffer_heads, and then submit them for I/O on the second pass.
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 */
STATIC void
xfs_submit_ioend(
	xfs_ioend_t		*ioend)
{
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	xfs_ioend_t		*head = ioend;
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	xfs_ioend_t		*next;
	struct buffer_head	*bh;
	struct bio		*bio;
	sector_t		lastblock = 0;

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	/* Pass 1 - start writeback */
	do {
		next = ioend->io_list;
		for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
			xfs_start_buffer_writeback(bh);
		}
	} while ((ioend = next) != NULL);

	/* Pass 2 - submit I/O */
	ioend = head;
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	do {
		next = ioend->io_list;
		bio = NULL;

		for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {

			if (!bio) {
 retry:
				bio = xfs_alloc_ioend_bio(bh);
			} else if (bh->b_blocknr != lastblock + 1) {
				xfs_submit_ioend_bio(ioend, bio);
				goto retry;
			}

			if (bio_add_buffer(bio, bh) != bh->b_size) {
				xfs_submit_ioend_bio(ioend, bio);
				goto retry;
			}

			lastblock = bh->b_blocknr;
		}
		if (bio)
			xfs_submit_ioend_bio(ioend, bio);
		xfs_finish_ioend(ioend);
	} while ((ioend = next) != NULL);
}

/*
 * Cancel submission of all buffer_heads so far in this endio.
 * Toss the endio too.  Only ever called for the initial page
 * in a writepage request, so only ever one page.
 */
STATIC void
xfs_cancel_ioend(
	xfs_ioend_t		*ioend)
{
	xfs_ioend_t		*next;
	struct buffer_head	*bh, *next_bh;

	do {
		next = ioend->io_list;
		bh = ioend->io_buffer_head;
		do {
			next_bh = bh->b_private;
			clear_buffer_async_write(bh);
			unlock_buffer(bh);
		} while ((bh = next_bh) != NULL);

		vn_iowake(ioend->io_vnode);
		mempool_free(ioend, xfs_ioend_pool);
	} while ((ioend = next) != NULL);
}

/*
 * Test to see if we've been building up a completion structure for
 * earlier buffers -- if so, we try to append to this ioend if we
 * can, otherwise we finish off any current ioend and start another.
 * Return true if we've finished the given ioend.
 */
STATIC void
xfs_add_to_ioend(
	struct inode		*inode,
	struct buffer_head	*bh,
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	xfs_off_t		offset,
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	unsigned int		type,
	xfs_ioend_t		**result,
	int			need_ioend)
{
	xfs_ioend_t		*ioend = *result;

	if (!ioend || need_ioend || type != ioend->io_type) {
		xfs_ioend_t	*previous = *result;

		ioend = xfs_alloc_ioend(inode, type);
		ioend->io_offset = offset;
		ioend->io_buffer_head = bh;
		ioend->io_buffer_tail = bh;
		if (previous)
			previous->io_list = ioend;
		*result = ioend;
	} else {
		ioend->io_buffer_tail->b_private = bh;
		ioend->io_buffer_tail = bh;
	}

	bh->b_private = NULL;
	ioend->io_size += bh->b_size;
}

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STATIC void
xfs_map_buffer(
	struct buffer_head	*bh,
	xfs_iomap_t		*mp,
	xfs_off_t		offset,
	uint			block_bits)
{
	sector_t		bn;

	ASSERT(mp->iomap_bn != IOMAP_DADDR_NULL);

	bn = (mp->iomap_bn >> (block_bits - BBSHIFT)) +
	      ((offset - mp->iomap_offset) >> block_bits);

	ASSERT(bn || (mp->iomap_flags & IOMAP_REALTIME));

	bh->b_blocknr = bn;
	set_buffer_mapped(bh);
}

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STATIC void
xfs_map_at_offset(
	struct buffer_head	*bh,
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	loff_t			offset,
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	int			block_bits,
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	xfs_iomap_t		*iomapp)
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{
	ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE));
	ASSERT(!(iomapp->iomap_flags & IOMAP_DELAY));

	lock_buffer(bh);
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	xfs_map_buffer(bh, iomapp, offset, block_bits);
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	bh->b_bdev = iomapp->iomap_target->bt_bdev;
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	set_buffer_mapped(bh);
	clear_buffer_delay(bh);
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	clear_buffer_unwritten(bh);
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}

/*
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 * Look for a page at index that is suitable for clustering.
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 */
STATIC unsigned int
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xfs_probe_page(
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	struct page		*page,
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	unsigned int		pg_offset,
	int			mapped)
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{
	int			ret = 0;

	if (PageWriteback(page))
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		return 0;
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	if (page->mapping && PageDirty(page)) {
		if (page_has_buffers(page)) {
			struct buffer_head	*bh, *head;

			bh = head = page_buffers(page);
			do {
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				if (!buffer_uptodate(bh))
					break;
				if (mapped != buffer_mapped(bh))
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					break;
				ret += bh->b_size;
				if (ret >= pg_offset)
					break;
			} while ((bh = bh->b_this_page) != head);
		} else
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			ret = mapped ? 0 : PAGE_CACHE_SIZE;
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	}

	return ret;
}

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STATIC size_t
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xfs_probe_cluster(
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	struct inode		*inode,
	struct page		*startpage,
	struct buffer_head	*bh,
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	struct buffer_head	*head,
	int			mapped)
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{
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	struct pagevec		pvec;
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	pgoff_t			tindex, tlast, tloff;
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	size_t			total = 0;
	int			done = 0, i;
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	/* First sum forwards in this page */
	do {
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		if (!buffer_uptodate(bh) || (mapped != buffer_mapped(bh)))
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			return total;
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		total += bh->b_size;
	} while ((bh = bh->b_this_page) != head);

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	/* if we reached the end of the page, sum forwards in following pages */
	tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
	tindex = startpage->index + 1;

	/* Prune this back to avoid pathological behavior */
	tloff = min(tlast, startpage->index + 64);

	pagevec_init(&pvec, 0);
	while (!done && tindex <= tloff) {
		unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);

		if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
			break;

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

			if (tindex == tlast) {
				pg_offset =
				    i_size_read(inode) & (PAGE_CACHE_SIZE - 1);
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				if (!pg_offset) {
					done = 1;
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					break;
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				}
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			} else
				pg_offset = PAGE_CACHE_SIZE;

			if (page->index == tindex && !TestSetPageLocked(page)) {
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				len = xfs_probe_page(page, pg_offset, mapped);
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				unlock_page(page);
			}

			if (!len) {
				done = 1;
				break;
			}

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			total += len;
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			tindex++;
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		}
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		pagevec_release(&pvec);
		cond_resched();
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	}
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	return total;
}

/*
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 * Test if a given page is suitable for writing as part of an unwritten
 * or delayed allocate extent.
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 */
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STATIC int
xfs_is_delayed_page(
	struct page		*page,
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	unsigned int		type)
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{
	if (PageWriteback(page))
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		return 0;
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	if (page->mapping && page_has_buffers(page)) {
		struct buffer_head	*bh, *head;
		int			acceptable = 0;

		bh = head = page_buffers(page);
		do {
642 643 644 645
			if (buffer_unwritten(bh))
				acceptable = (type == IOMAP_UNWRITTEN);
			else if (buffer_delay(bh))
				acceptable = (type == IOMAP_DELAY);
646
			else if (buffer_dirty(bh) && buffer_mapped(bh))
647
				acceptable = (type == 0);
648
			else
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				break;
		} while ((bh = bh->b_this_page) != head);

		if (acceptable)
653
			return 1;
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	}

656
	return 0;
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}

/*
 * Allocate & map buffers for page given the extent map. Write it out.
 * except for the original page of a writepage, this is called on
 * delalloc/unwritten pages only, for the original page it is possible
 * that the page has no mapping at all.
 */
665
STATIC int
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xfs_convert_page(
	struct inode		*inode,
	struct page		*page,
669
	loff_t			tindex,
670
	xfs_iomap_t		*mp,
671
	xfs_ioend_t		**ioendp,
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	struct writeback_control *wbc,
	int			startio,
	int			all_bh)
{
676
	struct buffer_head	*bh, *head;
677 678
	xfs_off_t		end_offset;
	unsigned long		p_offset;
679
	unsigned int		type;
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	int			bbits = inode->i_blkbits;
681
	int			len, page_dirty;
682
	int			count = 0, done = 0, uptodate = 1;
683
 	xfs_off_t		offset = page_offset(page);
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685 686 687 688 689 690 691 692 693 694 695
	if (page->index != tindex)
		goto fail;
	if (TestSetPageLocked(page))
		goto fail;
	if (PageWriteback(page))
		goto fail_unlock_page;
	if (page->mapping != inode->i_mapping)
		goto fail_unlock_page;
	if (!xfs_is_delayed_page(page, (*ioendp)->io_type))
		goto fail_unlock_page;

696 697
	/*
	 * page_dirty is initially a count of buffers on the page before
698
	 * EOF and is decremented as we move each into a cleanable state.
699 700 701 702 703 704 705 706 707
	 *
	 * Derivation:
	 *
	 * End offset is the highest offset that this page should represent.
	 * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
	 * will evaluate non-zero and be less than PAGE_CACHE_SIZE and
	 * hence give us the correct page_dirty count. On any other page,
	 * it will be zero and in that case we need page_dirty to be the
	 * count of buffers on the page.
708
	 */
709 710 711 712
	end_offset = min_t(unsigned long long,
			(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
			i_size_read(inode));

713
	len = 1 << inode->i_blkbits;
714 715 716 717
	p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
					PAGE_CACHE_SIZE);
	p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
	page_dirty = p_offset / len;
718

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	bh = head = page_buffers(page);
	do {
721
		if (offset >= end_offset)
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			break;
723 724 725 726
		if (!buffer_uptodate(bh))
			uptodate = 0;
		if (!(PageUptodate(page) || buffer_uptodate(bh))) {
			done = 1;
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			continue;
728 729
		}

730 731 732 733 734 735 736
		if (buffer_unwritten(bh) || buffer_delay(bh)) {
			if (buffer_unwritten(bh))
				type = IOMAP_UNWRITTEN;
			else
				type = IOMAP_DELAY;

			if (!xfs_iomap_valid(mp, offset)) {
737
				done = 1;
738 739 740 741 742 743 744 745
				continue;
			}

			ASSERT(!(mp->iomap_flags & IOMAP_HOLE));
			ASSERT(!(mp->iomap_flags & IOMAP_DELAY));

			xfs_map_at_offset(bh, offset, bbits, mp);
			if (startio) {
746
				xfs_add_to_ioend(inode, bh, offset,
747 748 749 750 751 752 753 754 755 756 757
						type, ioendp, done);
			} else {
				set_buffer_dirty(bh);
				unlock_buffer(bh);
				mark_buffer_dirty(bh);
			}
			page_dirty--;
			count++;
		} else {
			type = 0;
			if (buffer_mapped(bh) && all_bh && startio) {
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				lock_buffer(bh);
759
				xfs_add_to_ioend(inode, bh, offset,
760 761
						type, ioendp, done);
				count++;
762
				page_dirty--;
763 764
			} else {
				done = 1;
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			}
		}
767
	} while (offset += len, (bh = bh->b_this_page) != head);
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769 770 771 772
	if (uptodate && bh == head)
		SetPageUptodate(page);

	if (startio) {
773 774 775 776
		if (count) {
			struct backing_dev_info *bdi;

			bdi = inode->i_mapping->backing_dev_info;
777
			wbc->nr_to_write--;
778 779 780
			if (bdi_write_congested(bdi)) {
				wbc->encountered_congestion = 1;
				done = 1;
781
			} else if (wbc->nr_to_write <= 0) {
782 783 784
				done = 1;
			}
		}
785
		xfs_start_page_writeback(page, wbc, !page_dirty, count);
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	}
787 788

	return done;
789 790 791 792
 fail_unlock_page:
	unlock_page(page);
 fail:
	return 1;
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}

/*
 * Convert & write out a cluster of pages in the same extent as defined
 * by mp and following the start page.
 */
STATIC void
xfs_cluster_write(
	struct inode		*inode,
	pgoff_t			tindex,
	xfs_iomap_t		*iomapp,
804
	xfs_ioend_t		**ioendp,
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	struct writeback_control *wbc,
	int			startio,
	int			all_bh,
	pgoff_t			tlast)
{
810 811
	struct pagevec		pvec;
	int			done = 0, i;
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813 814 815 816 817
	pagevec_init(&pvec, 0);
	while (!done && tindex <= tlast) {
		unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);

		if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
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			break;
819 820 821 822 823 824 825 826 827 828

		for (i = 0; i < pagevec_count(&pvec); i++) {
			done = xfs_convert_page(inode, pvec.pages[i], tindex++,
					iomapp, ioendp, wbc, startio, all_bh);
			if (done)
				break;
		}

		pagevec_release(&pvec);
		cond_resched();
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	}
}

/*
 * Calling this without startio set means we are being asked to make a dirty
 * page ready for freeing it's buffers.  When called with startio set then
 * we are coming from writepage.
 *
 * When called with startio set it is important that we write the WHOLE
 * page if possible.
 * The bh->b_state's cannot know if any of the blocks or which block for
 * that matter are dirty due to mmap writes, and therefore bh uptodate is
841
 * only valid if the page itself isn't completely uptodate.  Some layers
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 * may clear the page dirty flag prior to calling write page, under the
 * assumption the entire page will be written out; by not writing out the
 * whole page the page can be reused before all valid dirty data is
 * written out.  Note: in the case of a page that has been dirty'd by
 * mapwrite and but partially setup by block_prepare_write the
 * bh->b_states's will not agree and only ones setup by BPW/BCW will have
 * valid state, thus the whole page must be written out thing.
 */

STATIC int
xfs_page_state_convert(
	struct inode	*inode,
	struct page	*page,
	struct writeback_control *wbc,
	int		startio,
	int		unmapped) /* also implies page uptodate */
{
859
	struct buffer_head	*bh, *head;
860
	xfs_iomap_t		iomap;
861
	xfs_ioend_t		*ioend = NULL, *iohead = NULL;
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	loff_t			offset;
	unsigned long           p_offset = 0;
864
	unsigned int		type;
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865 866
	__uint64_t              end_offset;
	pgoff_t                 end_index, last_index, tlast;
867 868
	ssize_t			size, len;
	int			flags, err, iomap_valid = 0, uptodate = 1;
869 870
	int			page_dirty, count = 0;
	int			trylock = 0;
871
	int			all_bh = unmapped;
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873 874 875 876
	if (startio) {
		if (wbc->sync_mode == WB_SYNC_NONE && wbc->nonblocking)
			trylock |= BMAPI_TRYLOCK;
	}
877

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	/* Is this page beyond the end of the file? */
	offset = i_size_read(inode);
	end_index = offset >> PAGE_CACHE_SHIFT;
	last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
	if (page->index >= end_index) {
		if ((page->index >= end_index + 1) ||
		    !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
885 886 887
			if (startio)
				unlock_page(page);
			return 0;
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		}
	}

	/*
892
	 * page_dirty is initially a count of buffers on the page before
893
	 * EOF and is decremented as we move each into a cleanable state.
894 895 896 897 898 899 900 901 902 903 904 905
	 *
	 * Derivation:
	 *
	 * End offset is the highest offset that this page should represent.
	 * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
	 * will evaluate non-zero and be less than PAGE_CACHE_SIZE and
	 * hence give us the correct page_dirty count. On any other page,
	 * it will be zero and in that case we need page_dirty to be the
	 * count of buffers on the page.
 	 */
	end_offset = min_t(unsigned long long,
			(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
906
	len = 1 << inode->i_blkbits;
907 908 909
	p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
					PAGE_CACHE_SIZE);
	p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
910 911 912
	page_dirty = p_offset / len;

	bh = head = page_buffers(page);
913
	offset = page_offset(page);
914 915
	flags = -1;
	type = 0;
916 917

	/* TODO: cleanup count and page_dirty */
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	do {
		if (offset >= end_offset)
			break;
		if (!buffer_uptodate(bh))
			uptodate = 0;
924
		if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio) {
925 926 927 928 929
			/*
			 * the iomap is actually still valid, but the ioend
			 * isn't.  shouldn't happen too often.
			 */
			iomap_valid = 0;
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			continue;
931
		}
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933 934
		if (iomap_valid)
			iomap_valid = xfs_iomap_valid(&iomap, offset);
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		/*
		 * First case, map an unwritten extent and prepare for
		 * extent state conversion transaction on completion.
939
		 *
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		 * Second case, allocate space for a delalloc buffer.
		 * We can return EAGAIN here in the release page case.
942 943 944 945 946 947 948
		 *
		 * Third case, an unmapped buffer was found, and we are
		 * in a path where we need to write the whole page out.
 		 */
		if (buffer_unwritten(bh) || buffer_delay(bh) ||
		    ((buffer_uptodate(bh) || PageUptodate(page)) &&
		     !buffer_mapped(bh) && (unmapped || startio))) {
949 950 951 952 953 954
		     	/*
			 * Make sure we don't use a read-only iomap
			 */
		     	if (flags == BMAPI_READ)
				iomap_valid = 0;

955 956
			if (buffer_unwritten(bh)) {
				type = IOMAP_UNWRITTEN;
957
				flags = BMAPI_WRITE | BMAPI_IGNSTATE;
958
			} else if (buffer_delay(bh)) {
959
				type = IOMAP_DELAY;
960
				flags = BMAPI_ALLOCATE | trylock;
961
			} else {
962
				type = IOMAP_NEW;
963
				flags = BMAPI_WRITE | BMAPI_MMAP;
964 965
			}

966
			if (!iomap_valid) {
967 968 969
				if (type == IOMAP_NEW) {
					size = xfs_probe_cluster(inode,
							page, bh, head, 0);
970 971 972 973 974 975
				} else {
					size = len;
				}

				err = xfs_map_blocks(inode, offset, size,
						&iomap, flags);
976
				if (err)
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					goto error;
978
				iomap_valid = xfs_iomap_valid(&iomap, offset);
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979
			}
980 981 982
			if (iomap_valid) {
				xfs_map_at_offset(bh, offset,
						inode->i_blkbits, &iomap);
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				if (startio) {
984
					xfs_add_to_ioend(inode, bh, offset,
985 986
							type, &ioend,
							!iomap_valid);
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				} else {
					set_buffer_dirty(bh);
					unlock_buffer(bh);
					mark_buffer_dirty(bh);
				}
				page_dirty--;
993
				count++;
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			}
995
		} else if (buffer_uptodate(bh) && startio) {
996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010
			/*
			 * we got here because the buffer is already mapped.
			 * That means it must already have extents allocated
			 * underneath it. Map the extent by reading it.
			 */
			if (!iomap_valid || type != 0) {
				flags = BMAPI_READ;
				size = xfs_probe_cluster(inode, page, bh,
								head, 1);
				err = xfs_map_blocks(inode, offset, size,
						&iomap, flags);
				if (err)
					goto error;
				iomap_valid = xfs_iomap_valid(&iomap, offset);
			}
1011

1012
			type = 0;
1013 1014
			if (!test_and_set_bit(BH_Lock, &bh->b_state)) {
				ASSERT(buffer_mapped(bh));
1015 1016
				if (iomap_valid)
					all_bh = 1;
1017
				xfs_add_to_ioend(inode, bh, offset, type,
1018 1019 1020
						&ioend, !iomap_valid);
				page_dirty--;
				count++;
1021
			} else {
1022
				iomap_valid = 0;
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			}
1024 1025 1026
		} else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
			   (unmapped || startio)) {
			iomap_valid = 0;
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		}
1028 1029 1030 1031 1032

		if (!iohead)
			iohead = ioend;

	} while (offset += len, ((bh = bh->b_this_page) != head));
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	if (uptodate && bh == head)
		SetPageUptodate(page);

1037 1038
	if (startio)
		xfs_start_page_writeback(page, wbc, 1, count);
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1040 1041
	if (ioend && iomap_valid) {
		offset = (iomap.iomap_offset + iomap.iomap_bsize - 1) >>
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					PAGE_CACHE_SHIFT;
1043
		tlast = min_t(pgoff_t, offset, last_index);
1044
		xfs_cluster_write(inode, page->index + 1, &iomap, &ioend,
1045
					wbc, startio, all_bh, tlast);
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1046 1047
	}

1048 1049 1050
	if (iohead)
		xfs_submit_ioend(iohead);

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1051 1052 1053
	return page_dirty;

error:
1054 1055
	if (iohead)
		xfs_cancel_ioend(iohead);
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1056 1057 1058 1059 1060 1061 1062

	/*
	 * If it's delalloc and we have nowhere to put it,
	 * throw it away, unless the lower layers told
	 * us to try again.
	 */
	if (err != -EAGAIN) {
1063
		if (!unmapped)
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			block_invalidatepage(page, 0);
		ClearPageUptodate(page);
	}
	return err;
}

1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090
/*
 * writepage: Called from one of two places:
 *
 * 1. we are flushing a delalloc buffer head.
 *
 * 2. we are writing out a dirty page. Typically the page dirty
 *    state is cleared before we get here. In this case is it
 *    conceivable we have no buffer heads.
 *
 * For delalloc space on the page we need to allocate space and
 * flush it. For unmapped buffer heads on the page we should
 * allocate space if the page is uptodate. For any other dirty
 * buffer heads on the page we should flush them.
 *
 * If we detect that a transaction would be required to flush
 * the page, we have to check the process flags first, if we
 * are already in a transaction or disk I/O during allocations
 * is off, we need to fail the writepage and redirty the page.
 */

STATIC int
1091
xfs_vm_writepage(
1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125
	struct page		*page,
	struct writeback_control *wbc)
{
	int			error;
	int			need_trans;
	int			delalloc, unmapped, unwritten;
	struct inode		*inode = page->mapping->host;

	xfs_page_trace(XFS_WRITEPAGE_ENTER, inode, page, 0);

	/*
	 * We need a transaction if:
	 *  1. There are delalloc buffers on the page
	 *  2. The page is uptodate and we have unmapped buffers
	 *  3. The page is uptodate and we have no buffers
	 *  4. There are unwritten buffers on the page
	 */

	if (!page_has_buffers(page)) {
		unmapped = 1;
		need_trans = 1;
	} else {
		xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
		if (!PageUptodate(page))
			unmapped = 0;
		need_trans = delalloc + unmapped + unwritten;
	}

	/*
	 * If we need a transaction and the process flags say
	 * we are already in a transaction, or no IO is allowed
	 * then mark the page dirty again and leave the page
	 * as is.
	 */
1126
	if (current_test_flags(PF_FSTRANS) && need_trans)
1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156
		goto out_fail;

	/*
	 * Delay hooking up buffer heads until we have
	 * made our go/no-go decision.
	 */
	if (!page_has_buffers(page))
		create_empty_buffers(page, 1 << inode->i_blkbits, 0);

	/*
	 * Convert delayed allocate, unwritten or unmapped space
	 * to real space and flush out to disk.
	 */
	error = xfs_page_state_convert(inode, page, wbc, 1, unmapped);
	if (error == -EAGAIN)
		goto out_fail;
	if (unlikely(error < 0))
		goto out_unlock;

	return 0;

out_fail:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
	return 0;
out_unlock:
	unlock_page(page);
	return error;
}

1157 1158 1159 1160 1161
STATIC int
xfs_vm_writepages(
	struct address_space	*mapping,
	struct writeback_control *wbc)
{
1162
	struct bhv_vnode	*vp = vn_from_inode(mapping->host);
1163 1164 1165 1166 1167 1168

	if (VN_TRUNC(vp))
		VUNTRUNCATE(vp);
	return generic_writepages(mapping, wbc);
}

1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188
/*
 * Called to move a page into cleanable state - and from there
 * to be released. Possibly the page is already clean. We always
 * have buffer heads in this call.
 *
 * Returns 0 if the page is ok to release, 1 otherwise.
 *
 * Possible scenarios are:
 *
 * 1. We are being called to release a page which has been written
 *    to via regular I/O. buffer heads will be dirty and possibly
 *    delalloc. If no delalloc buffer heads in this case then we
 *    can just return zero.
 *
 * 2. We are called to release a page which has been written via
 *    mmap, all we need to do is ensure there is no delalloc
 *    state in the buffer heads, if not we can let the caller
 *    free them and we should come back later via writepage.
 */
STATIC int
1189
xfs_vm_releasepage(
1190 1191 1192 1193 1194 1195 1196 1197 1198 1199
	struct page		*page,
	gfp_t			gfp_mask)
{
	struct inode		*inode = page->mapping->host;
	int			dirty, delalloc, unmapped, unwritten;
	struct writeback_control wbc = {
		.sync_mode = WB_SYNC_ALL,
		.nr_to_write = 1,
	};

1200
	xfs_page_trace(XFS_RELEASEPAGE_ENTER, inode, page, 0);
1201

1202 1203 1204
	if (!page_has_buffers(page))
		return 0;

1205 1206 1207 1208 1209 1210 1211 1212 1213 1214
	xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
	if (!delalloc && !unwritten)
		goto free_buffers;

	if (!(gfp_mask & __GFP_FS))
		return 0;

	/* If we are already inside a transaction or the thread cannot
	 * do I/O, we cannot release this page.
	 */
1215
	if (current_test_flags(PF_FSTRANS))
1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232
		return 0;

	/*
	 * Convert delalloc space to real space, do not flush the
	 * data out to disk, that will be done by the caller.
	 * Never need to allocate space here - we will always
	 * come back to writepage in that case.
	 */
	dirty = xfs_page_state_convert(inode, page, &wbc, 0, 0);
	if (dirty == 0 && !unwritten)
		goto free_buffers;
	return 0;

free_buffers:
	return try_to_free_buffers(page);
}

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STATIC int
1234
__xfs_get_blocks(
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	struct inode		*inode,
	sector_t		iblock,
	struct buffer_head	*bh_result,
	int			create,
	int			direct,
	bmapi_flags_t		flags)
{
1242
	bhv_vnode_t		*vp = vn_from_inode(inode);
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	xfs_iomap_t		iomap;
1244 1245
	xfs_off_t		offset;
	ssize_t			size;
1246
	int			niomap = 1;
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	int			error;

1249
	offset = (xfs_off_t)iblock << inode->i_blkbits;
1250 1251
	ASSERT(bh_result->b_size >= (1 << inode->i_blkbits));
	size = bh_result->b_size;
1252 1253
	error = bhv_vop_bmap(vp, offset, size,
			     create ? flags : BMAPI_READ, &iomap, &niomap);
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	if (error)
		return -error;
1256
	if (niomap == 0)
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		return 0;

	if (iomap.iomap_bn != IOMAP_DADDR_NULL) {
1260 1261
		/*
		 * For unwritten extents do not report a disk address on
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		 * the read case (treat as if we're reading into a hole).
		 */
		if (create || !(iomap.iomap_flags & IOMAP_UNWRITTEN)) {
1265 1266
			xfs_map_buffer(bh_result, &iomap, offset,
				       inode->i_blkbits);
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		}
		if (create && (iomap.iomap_flags & IOMAP_UNWRITTEN)) {
			if (direct)
				bh_result->b_private = inode;
			set_buffer_unwritten(bh_result);
			set_buffer_delay(bh_result);
		}
	}

1276 1277 1278 1279
	/*
	 * If this is a realtime file, data may be on a different device.
	 * to that pointed to from the buffer_head b_bdev currently.
	 */
1280
	bh_result->b_bdev = iomap.iomap_target->bt_bdev;
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1282 1283 1284 1285
	/*
	 * If we previously allocated a block out beyond eof and we are
	 * now coming back to use it then we will need to flag it as new
	 * even if it has a disk address.
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	 */
	if (create &&
	    ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
1289
	     (offset >= i_size_read(inode)) || (iomap.iomap_flags & IOMAP_NEW)))
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		set_buffer_new(bh_result);

	if (iomap.iomap_flags & IOMAP_DELAY) {
		BUG_ON(direct);
		if (create) {
			set_buffer_uptodate(bh_result);
			set_buffer_mapped(bh_result);
			set_buffer_delay(bh_result);
		}
	}

1301
	if (direct || size > (1 << inode->i_blkbits)) {
1302 1303
		ASSERT(iomap.iomap_bsize - iomap.iomap_delta > 0);
		offset = min_t(xfs_off_t,
1304 1305
				iomap.iomap_bsize - iomap.iomap_delta, size);
		bh_result->b_size = (ssize_t)min_t(xfs_off_t, LONG_MAX, offset);
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	}

	return 0;
}

int
1312
xfs_get_blocks(
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	struct inode		*inode,
	sector_t		iblock,
	struct buffer_head	*bh_result,
	int			create)
{
1318
	return __xfs_get_blocks(inode, iblock,
1319
				bh_result, create, 0, BMAPI_WRITE);
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}

STATIC int
1323
xfs_get_blocks_direct(
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	struct inode		*inode,
	sector_t		iblock,
	struct buffer_head	*bh_result,
	int			create)
{
1329
	return __xfs_get_blocks(inode, iblock,
1330
				bh_result, create, 1, BMAPI_WRITE|BMAPI_DIRECT);
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}

1333
STATIC void
1334
xfs_end_io_direct(
1335 1336 1337 1338 1339 1340 1341 1342 1343 1344
	struct kiocb	*iocb,
	loff_t		offset,
	ssize_t		size,
	void		*private)
{
	xfs_ioend_t	*ioend = iocb->private;

	/*
	 * Non-NULL private data means we need to issue a transaction to
	 * convert a range from unwritten to written extents.  This needs
1345
	 * to happen from process context but aio+dio I/O completion
1346
	 * happens from irq context so we need to defer it to a workqueue.
1347
	 * This is not necessary for synchronous direct I/O, but we do
1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
	 * it anyway to keep the code uniform and simpler.
	 *
	 * The core direct I/O code might be changed to always call the
	 * completion handler in the future, in which case all this can
	 * go away.
	 */
	if (private && size > 0) {
		ioend->io_offset = offset;
		ioend->io_size = size;
		xfs_finish_ioend(ioend);
	} else {
		xfs_destroy_ioend(ioend);
	}

	/*
1363
	 * blockdev_direct_IO can return an error even after the I/O
1364 1365 1366 1367 1368 1369
	 * completion handler was called.  Thus we need to protect
	 * against double-freeing.
	 */
	iocb->private = NULL;
}

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STATIC ssize_t
1371
xfs_vm_direct_IO(
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	int			rw,
	struct kiocb		*iocb,
	const struct iovec	*iov,
	loff_t			offset,
	unsigned long		nr_segs)
{
	struct file	*file = iocb->ki_filp;
	struct inode	*inode = file->f_mapping->host;
1380
	bhv_vnode_t	*vp = vn_from_inode(inode);
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	xfs_iomap_t	iomap;
	int		maps = 1;
	int		error;
1384
	ssize_t		ret;
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1386
	error = bhv_vop_bmap(vp, offset, 0, BMAPI_DEVICE, &iomap, &maps);
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	if (error)
		return -error;

1390
	iocb->private = xfs_alloc_ioend(inode, IOMAP_UNWRITTEN);
1391

1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404
	if (rw == WRITE) {
		ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
			iomap.iomap_target->bt_bdev,
			iov, offset, nr_segs,
			xfs_get_blocks_direct,
			xfs_end_io_direct);
	} else {
		ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
			iomap.iomap_target->bt_bdev,
			iov, offset, nr_segs,
			xfs_get_blocks_direct,
			xfs_end_io_direct);
	}
1405 1406 1407 1408

	if (unlikely(ret <= 0 && iocb->private))
		xfs_destroy_ioend(iocb->private);
	return ret;
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}

1411
STATIC int
1412
xfs_vm_prepare_write(
1413 1414 1415 1416 1417
	struct file		*file,
	struct page		*page,
	unsigned int		from,
	unsigned int		to)
{
1418
	return block_prepare_write(page, from, to, xfs_get_blocks);
1419
}
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STATIC sector_t
1422
xfs_vm_bmap(
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	struct address_space	*mapping,
	sector_t		block)
{
	struct inode		*inode = (struct inode *)mapping->host;
1427
	bhv_vnode_t		*vp = vn_from_inode(inode);
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1429
	vn_trace_entry(vp, __FUNCTION__, (inst_t *)__return_address);
1430 1431 1432
	bhv_vop_rwlock(vp, VRWLOCK_READ);
	bhv_vop_flush_pages(vp, (xfs_off_t)0, -1, 0, FI_REMAPF);
	bhv_vop_rwunlock(vp, VRWLOCK_READ);
1433
	return generic_block_bmap(mapping, block, xfs_get_blocks);
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}

STATIC int
1437
xfs_vm_readpage(
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	struct file		*unused,
	struct page		*page)
{
1441
	return mpage_readpage(page, xfs_get_blocks);
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}

STATIC int
1445
xfs_vm_readpages(
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	struct file		*unused,
	struct address_space	*mapping,
	struct list_head	*pages,
	unsigned		nr_pages)
{
1451
	return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
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}

1454
STATIC void
1455
xfs_vm_invalidatepage(
1456 1457 1458 1459 1460
	struct page		*page,
	unsigned long		offset)
{
	xfs_page_trace(XFS_INVALIDPAGE_ENTER,
			page->mapping->host, page, offset);
1461
	block_invalidatepage(page, offset);
1462 1463
}

1464
const struct address_space_operations xfs_address_space_operations = {
1465 1466 1467
	.readpage		= xfs_vm_readpage,
	.readpages		= xfs_vm_readpages,
	.writepage		= xfs_vm_writepage,
1468
	.writepages		= xfs_vm_writepages,
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	.sync_page		= block_sync_page,
1470 1471
	.releasepage		= xfs_vm_releasepage,
	.invalidatepage		= xfs_vm_invalidatepage,
1472
	.prepare_write		= xfs_vm_prepare_write,
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	.commit_write		= generic_commit_write,
1474 1475
	.bmap			= xfs_vm_bmap,
	.direct_IO		= xfs_vm_direct_IO,
1476
	.migratepage		= buffer_migrate_page,
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};