xfs_aops.c

h内核

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.	 Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

#include "xfs.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_sb.h"
#include "xfs_dir.h"
#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_alloc.h"
#include "xfs_btree.h"
#include "xfs_attr_sf.h"
#include "xfs_dir_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_error.h"
#include "xfs_rw.h"
#include "xfs_iomap.h"
#include <linux/mpage.h>
#include <linux/writeback.h>

STATIC void xfs_count_page_state(struct page *, int *, int *, int *);
STATIC void xfs_convert_page(struct inode *, struct page *, xfs_iomap_t *,
		struct writeback_control *wbc, void *, int, int);

#if defined(XFS_RW_TRACE)
void
xfs_page_trace(
	int		tag,
	struct inode	*inode,
	struct page	*page,
	int		mask)
{
	xfs_inode_t	*ip;
	bhv_desc_t	*bdp;
	vnode_t		*vp = LINVFS_GET_VP(inode);
	loff_t		isize = i_size_read(inode);
	loff_t		offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
	int		delalloc = -1, unmapped = -1, unwritten = -1;

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

	bdp = vn_bhv_lookup(VN_BHV_HEAD(vp), &xfs_vnodeops);
	ip = XFS_BHVTOI(bdp);
	if (!ip->i_rwtrace)
		return;

	ktrace_enter(ip->i_rwtrace,
		(void *)((unsigned long)tag),
		(void *)ip,
		(void *)inode,
		(void *)page,
		(void *)((unsigned long)mask),
		(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),
		(void *)NULL,
		(void *)NULL);
}
#else
#define xfs_page_trace(tag, inode, page, mask)
#endif

void
linvfs_unwritten_done(
	struct buffer_head	*bh,
	int			uptodate)
{
	xfs_buf_t		*pb = (xfs_buf_t *)bh->b_private;

	ASSERT(buffer_unwritten(bh));
	bh->b_end_io = NULL;
	clear_buffer_unwritten(bh);
	if (!uptodate)
		pagebuf_ioerror(pb, EIO);
	if (atomic_dec_and_test(&pb->pb_io_remaining) == 1) {
		pagebuf_iodone(pb, 1, 1);
	}
	end_buffer_async_write(bh, uptodate);
}

/*
 * Issue transactions to convert a buffer range from unwritten
 * to written extents (buffered IO).
 */
STATIC void
linvfs_unwritten_convert(
	xfs_buf_t	*bp)
{
	vnode_t		*vp = XFS_BUF_FSPRIVATE(bp, vnode_t *);
	int		error;

	BUG_ON(atomic_read(&bp->pb_hold) < 1);
	VOP_BMAP(vp, XFS_BUF_OFFSET(bp), XFS_BUF_SIZE(bp),
			BMAPI_UNWRITTEN, NULL, NULL, error);
	XFS_BUF_SET_FSPRIVATE(bp, NULL);
	XFS_BUF_CLR_IODONE_FUNC(bp);
	XFS_BUF_UNDATAIO(bp);
	iput(LINVFS_GET_IP(vp));
	pagebuf_iodone(bp, 0, 0);
}

/*
 * Issue transactions to convert a buffer range from unwritten
 * to written extents (direct IO).
 */
STATIC void
linvfs_unwritten_convert_direct(
	struct inode	*inode,
	loff_t		offset,
	ssize_t		size,
	void		*private)
{
	ASSERT(!private || inode == (struct inode *)private);

	/* private indicates an unwritten extent lay beneath this IO */
	if (private && size > 0) {
		vnode_t	*vp = LINVFS_GET_VP(inode);
		int	error;

		VOP_BMAP(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL, error);
	}
}

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

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

/*
 * Finds the corresponding mapping in block @map array of the
 * given @offset within a @page.
 */
STATIC xfs_iomap_t *
xfs_offset_to_map(
	struct page		*page,
	xfs_iomap_t		*iomapp,
	unsigned long		offset)
{
	loff_t			full_offset;	/* offset from start of file */

	ASSERT(offset < PAGE_CACHE_SIZE);

	full_offset = page->index;		/* NB: using 64bit number */
	full_offset <<= PAGE_CACHE_SHIFT;	/* offset from file start */
	full_offset += offset;			/* offset from page start */

	if (full_offset < iomapp->iomap_offset)
		return NULL;
	if (iomapp->iomap_offset + (iomapp->iomap_bsize -1) >= full_offset)
		return iomapp;
	return NULL;
}

STATIC void
xfs_map_at_offset(
	struct page		*page,
	struct buffer_head	*bh,
	unsigned long		offset,
	int			block_bits,
	xfs_iomap_t		*iomapp)
{
	xfs_daddr_t		bn;
	loff_t			delta;
	int			sector_shift;

	ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE));
	ASSERT(!(iomapp->iomap_flags & IOMAP_DELAY));
	ASSERT(iomapp->iomap_bn != IOMAP_DADDR_NULL);

	delta = page->index;
	delta <<= PAGE_CACHE_SHIFT;
	delta += offset;
	delta -= iomapp->iomap_offset;
	delta >>= block_bits;

	sector_shift = block_bits - BBSHIFT;
	bn = iomapp->iomap_bn >> sector_shift;
	bn += delta;
	BUG_ON(!bn && !(iomapp->iomap_flags & IOMAP_REALTIME));
	ASSERT((bn << sector_shift) >= iomapp->iomap_bn);

	lock_buffer(bh);
	bh->b_blocknr = bn;
	bh->b_bdev = iomapp->iomap_target->pbr_bdev;
	set_buffer_mapped(bh);
	clear_buffer_delay(bh);
}

/*
 * Look for a page at index which is unlocked and contains our
 * unwritten extent flagged buffers at its head.  Returns page
 * locked and with an extra reference count, and length of the
 * unwritten extent component on this page that we can write,
 * in units of filesystem blocks.
 */
STATIC struct page *
xfs_probe_unwritten_page(
	struct address_space	*mapping,
	pgoff_t			index,
	xfs_iomap_t		*iomapp,
	xfs_buf_t		*pb,
	unsigned long		max_offset,
	unsigned long		*fsbs,
	unsigned int            bbits)
{
	struct page		*page;

	page = find_trylock_page(mapping, index);
	if (!page)
		return NULL;
	if (PageWriteback(page))
		goto out;

	if (page->mapping && page_has_buffers(page)) {
		struct buffer_head	*bh, *head;
		unsigned long		p_offset = 0;

		*fsbs = 0;
		bh = head = page_buffers(page);
		do {
			if (!buffer_unwritten(bh) || !buffer_uptodate(bh))
				break;
			if (!xfs_offset_to_map(page, iomapp, p_offset))
				break;
			if (p_offset >= max_offset)
				break;
			xfs_map_at_offset(page, bh, p_offset, bbits, iomapp);
			set_buffer_unwritten_io(bh);
			bh->b_private = pb;
			p_offset += bh->b_size;
			(*fsbs)++;
		} while ((bh = bh->b_this_page) != head);

		if (p_offset)
			return page;
	}

out:
	unlock_page(page);
	return NULL;
}

/*
 * Look for a page at index which is unlocked and not mapped
 * yet - clustering for mmap write case.
 */
STATIC unsigned int
xfs_probe_unmapped_page(
	struct address_space	*mapping,
	pgoff_t			index,
	unsigned int		pg_offset)
{
	struct page		*page;
	int			ret = 0;

	page = find_trylock_page(mapping, index);
	if (!page)
		return 0;
	if (PageWriteback(page))
		goto out;

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

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

out:
	unlock_page(page);
	return ret;
}

STATIC unsigned int
xfs_probe_unmapped_cluster(
	struct inode		*inode,
	struct page		*startpage,
	struct buffer_head	*bh,
	struct buffer_head	*head)
{
	pgoff_t			tindex, tlast, tloff;
	unsigned int		pg_offset, len, total = 0;
	struct address_space	*mapping = inode->i_mapping;

	/* First sum forwards in this page */
	do {
		if (buffer_mapped(bh))
			break;
		total += bh->b_size;
	} while ((bh = bh->b_this_page) != head);

	/* If we reached the end of the page, sum forwards in
	 * following pages.
	 */
	if (bh == head) {
		tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
		/* Prune this back to avoid pathological behavior */
		tloff = min(tlast, startpage->index + 64);
		for (tindex = startpage->index + 1; tindex < tloff; tindex++) {
			len = xfs_probe_unmapped_page(mapping, tindex,
							PAGE_CACHE_SIZE);
			if (!len)
				return total;
			total += len;
		}
		if (tindex == tlast &&
		    (pg_offset = i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
			total += xfs_probe_unmapped_page(mapping,
							tindex, pg_offset);
		}
	}
	return total;
}

/*
 * Probe for a given page (index) in the inode and test if it is delayed
 * and without unwritten buffers.  Returns page locked and with an extra
 * reference count.
 */
STATIC struct page *
xfs_probe_delalloc_page(
	struct inode		*inode,
	pgoff_t			index)
{
	struct page		*page;

	page = find_trylock_page(inode->i_mapping, index);
	if (!page)
		return NULL;
	if (PageWriteback(page))
		goto out;

	if (page->mapping && page_has_buffers(page)) {
		struct buffer_head	*bh, *head;
		int			acceptable = 0;

		bh = head = page_buffers(page);
		do {
			if (buffer_unwritten(bh)) {
				acceptable = 0;
				break;
			} else if (buffer_delay(bh)) {
				acceptable = 1;
			}
		} while ((bh = bh->b_this_page) != head);

		if (acceptable)
			return page;
	}

out:
	unlock_page(page);
	return NULL;
}

STATIC int
xfs_map_unwritten(
	struct inode		*inode,
	struct page		*start_page,
	struct buffer_head	*head,
	struct buffer_head	*curr,