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Commit a45c0ecc authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

iomap: move the swapfile code into a separate file 



Move the swapfile activation code into a separate file so that we can
group related functions in a single file instead of having a single
enormous source file.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 1c230208

fs/iomap.c

+0 −170
Original line number Diff line number Diff line
@@ -2000,176 +2000,6 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, 
}

EXPORT_SYMBOL_GPL(iomap_dio_rw);



/* Swapfile activation */



#ifdef CONFIG_SWAP

struct iomap_swapfile_info {

	struct iomap iomap;		/* accumulated iomap */

	struct swap_info_struct *sis;

	uint64_t lowest_ppage;		/* lowest physical addr seen (pages) */

	uint64_t highest_ppage;		/* highest physical addr seen (pages) */

	unsigned long nr_pages;		/* number of pages collected */

	int nr_extents;			/* extent count */

};



/*

 * Collect physical extents for this swap file.  Physical extents reported to

 * the swap code must be trimmed to align to a page boundary.  The logical

 * offset within the file is irrelevant since the swapfile code maps logical

 * page numbers of the swap device to the physical page-aligned extents.

 */

static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)

{

	struct iomap *iomap = &isi->iomap;

	unsigned long nr_pages;

	uint64_t first_ppage;

	uint64_t first_ppage_reported;

	uint64_t next_ppage;

	int error;



	/*

	 * Round the start up and the end down so that the physical

	 * extent aligns to a page boundary.

	 */

	first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;

	next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>

			PAGE_SHIFT;



	/* Skip too-short physical extents. */

	if (first_ppage >= next_ppage)

		return 0;

	nr_pages = next_ppage - first_ppage;



	/*

	 * Calculate how much swap space we're adding; the first page contains

	 * the swap header and doesn't count.  The mm still wants that first

	 * page fed to add_swap_extent, however.

	 */

	first_ppage_reported = first_ppage;

	if (iomap->offset == 0)

		first_ppage_reported++;

	if (isi->lowest_ppage > first_ppage_reported)

		isi->lowest_ppage = first_ppage_reported;

	if (isi->highest_ppage < (next_ppage - 1))

		isi->highest_ppage = next_ppage - 1;



	/* Add extent, set up for the next call. */

	error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage);

	if (error < 0)

		return error;

	isi->nr_extents += error;

	isi->nr_pages += nr_pages;

	return 0;

}



/*

 * Accumulate iomaps for this swap file.  We have to accumulate iomaps because

 * swap only cares about contiguous page-aligned physical extents and makes no

 * distinction between written and unwritten extents.

 */

static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,

		loff_t count, void *data, struct iomap *iomap)

{

	struct iomap_swapfile_info *isi = data;

	int error;



	switch (iomap->type) {

	case IOMAP_MAPPED:

	case IOMAP_UNWRITTEN:

		/* Only real or unwritten extents. */

		break;

	case IOMAP_INLINE:

		/* No inline data. */

		pr_err("swapon: file is inline\n");

		return -EINVAL;

	default:

		pr_err("swapon: file has unallocated extents\n");

		return -EINVAL;

	}



	/* No uncommitted metadata or shared blocks. */

	if (iomap->flags & IOMAP_F_DIRTY) {

		pr_err("swapon: file is not committed\n");

		return -EINVAL;

	}

	if (iomap->flags & IOMAP_F_SHARED) {

		pr_err("swapon: file has shared extents\n");

		return -EINVAL;

	}



	/* Only one bdev per swap file. */

	if (iomap->bdev != isi->sis->bdev) {

		pr_err("swapon: file is on multiple devices\n");

		return -EINVAL;

	}



	if (isi->iomap.length == 0) {

		/* No accumulated extent, so just store it. */

		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));

	} else if (isi->iomap.addr + isi->iomap.length == iomap->addr) {

		/* Append this to the accumulated extent. */

		isi->iomap.length += iomap->length;

	} else {

		/* Otherwise, add the retained iomap and store this one. */

		error = iomap_swapfile_add_extent(isi);

		if (error)

			return error;

		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));

	}

	return count;

}



/*

 * Iterate a swap file's iomaps to construct physical extents that can be

 * passed to the swapfile subsystem.

 */

int iomap_swapfile_activate(struct swap_info_struct *sis,

		struct file *swap_file, sector_t *pagespan,

		const struct iomap_ops *ops)

{

	struct iomap_swapfile_info isi = {

		.sis = sis,

		.lowest_ppage = (sector_t)-1ULL,

	};

	struct address_space *mapping = swap_file->f_mapping;

	struct inode *inode = mapping->host;

	loff_t pos = 0;

	loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE);

	loff_t ret;



	/*

	 * Persist all file mapping metadata so that we won't have any

	 * IOMAP_F_DIRTY iomaps.

	 */

	ret = vfs_fsync(swap_file, 1);

	if (ret)

		return ret;



	while (len > 0) {

		ret = iomap_apply(inode, pos, len, IOMAP_REPORT,

				ops, &isi, iomap_swapfile_activate_actor);

		if (ret <= 0)

			return ret;



		pos += ret;

		len -= ret;

	}



	if (isi.iomap.length) {

		ret = iomap_swapfile_add_extent(&isi);

		if (ret)

			return ret;

	}



	*pagespan = 1 + isi.highest_ppage - isi.lowest_ppage;

	sis->max = isi.nr_pages;

	sis->pages = isi.nr_pages - 1;

	sis->highest_bit = isi.nr_pages - 1;

	return isi.nr_extents;

}

EXPORT_SYMBOL_GPL(iomap_swapfile_activate);

#endif /* CONFIG_SWAP */



static loff_t

iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length,

		void *data, struct iomap *iomap)

fs/iomap/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -3,3 +3,6 @@ 
# Copyright (c) 2019 Oracle.

# All Rights Reserved.

#

obj-$(CONFIG_FS_IOMAP)		+= iomap.o



iomap-$(CONFIG_SWAP)		+= swapfile.o

fs/iomap/swapfile.c

0 → 100644
+180 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (C) 2018 Oracle.  All Rights Reserved.

 * Author: Darrick J. Wong <darrick.wong@oracle.com>

 */

#include <linux/module.h>

#include <linux/compiler.h>

#include <linux/fs.h>

#include <linux/iomap.h>

#include <linux/swap.h>



#include "../internal.h"



/* Swapfile activation */



struct iomap_swapfile_info {

	struct iomap iomap;		/* accumulated iomap */

	struct swap_info_struct *sis;

	uint64_t lowest_ppage;		/* lowest physical addr seen (pages) */

	uint64_t highest_ppage;		/* highest physical addr seen (pages) */

	unsigned long nr_pages;		/* number of pages collected */

	int nr_extents;			/* extent count */

};



/*

 * Collect physical extents for this swap file.  Physical extents reported to

 * the swap code must be trimmed to align to a page boundary.  The logical

 * offset within the file is irrelevant since the swapfile code maps logical

 * page numbers of the swap device to the physical page-aligned extents.

 */

static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)

{

	struct iomap *iomap = &isi->iomap;

	unsigned long nr_pages;

	uint64_t first_ppage;

	uint64_t first_ppage_reported;

	uint64_t next_ppage;

	int error;



	/*

	 * Round the start up and the end down so that the physical

	 * extent aligns to a page boundary.

	 */

	first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;

	next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>

			PAGE_SHIFT;



	/* Skip too-short physical extents. */

	if (first_ppage >= next_ppage)

		return 0;

	nr_pages = next_ppage - first_ppage;



	/*

	 * Calculate how much swap space we're adding; the first page contains

	 * the swap header and doesn't count.  The mm still wants that first

	 * page fed to add_swap_extent, however.

	 */

	first_ppage_reported = first_ppage;

	if (iomap->offset == 0)

		first_ppage_reported++;

	if (isi->lowest_ppage > first_ppage_reported)

		isi->lowest_ppage = first_ppage_reported;

	if (isi->highest_ppage < (next_ppage - 1))

		isi->highest_ppage = next_ppage - 1;



	/* Add extent, set up for the next call. */

	error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage);

	if (error < 0)

		return error;

	isi->nr_extents += error;

	isi->nr_pages += nr_pages;

	return 0;

}



/*

 * Accumulate iomaps for this swap file.  We have to accumulate iomaps because

 * swap only cares about contiguous page-aligned physical extents and makes no

 * distinction between written and unwritten extents.

 */

static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,

		loff_t count, void *data, struct iomap *iomap)

{

	struct iomap_swapfile_info *isi = data;

	int error;



	switch (iomap->type) {

	case IOMAP_MAPPED:

	case IOMAP_UNWRITTEN:

		/* Only real or unwritten extents. */

		break;

	case IOMAP_INLINE:

		/* No inline data. */

		pr_err("swapon: file is inline\n");

		return -EINVAL;

	default:

		pr_err("swapon: file has unallocated extents\n");

		return -EINVAL;

	}



	/* No uncommitted metadata or shared blocks. */

	if (iomap->flags & IOMAP_F_DIRTY) {

		pr_err("swapon: file is not committed\n");

		return -EINVAL;

	}

	if (iomap->flags & IOMAP_F_SHARED) {

		pr_err("swapon: file has shared extents\n");

		return -EINVAL;

	}



	/* Only one bdev per swap file. */

	if (iomap->bdev != isi->sis->bdev) {

		pr_err("swapon: file is on multiple devices\n");

		return -EINVAL;

	}



	if (isi->iomap.length == 0) {

		/* No accumulated extent, so just store it. */

		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));

	} else if (isi->iomap.addr + isi->iomap.length == iomap->addr) {

		/* Append this to the accumulated extent. */

		isi->iomap.length += iomap->length;

	} else {

		/* Otherwise, add the retained iomap and store this one. */

		error = iomap_swapfile_add_extent(isi);

		if (error)

			return error;

		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));

	}

	return count;

}



/*

 * Iterate a swap file's iomaps to construct physical extents that can be

 * passed to the swapfile subsystem.

 */

int iomap_swapfile_activate(struct swap_info_struct *sis,

		struct file *swap_file, sector_t *pagespan,

		const struct iomap_ops *ops)

{

	struct iomap_swapfile_info isi = {

		.sis = sis,

		.lowest_ppage = (sector_t)-1ULL,

	};

	struct address_space *mapping = swap_file->f_mapping;

	struct inode *inode = mapping->host;

	loff_t pos = 0;

	loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE);

	loff_t ret;



	/*

	 * Persist all file mapping metadata so that we won't have any

	 * IOMAP_F_DIRTY iomaps.

	 */

	ret = vfs_fsync(swap_file, 1);

	if (ret)

		return ret;



	while (len > 0) {

		ret = iomap_apply(inode, pos, len, IOMAP_REPORT,

				ops, &isi, iomap_swapfile_activate_actor);

		if (ret <= 0)

			return ret;



		pos += ret;

		len -= ret;

	}



	if (isi.iomap.length) {

		ret = iomap_swapfile_add_extent(&isi);

		if (ret)

			return ret;

	}



	*pagespan = 1 + isi.highest_ppage - isi.lowest_ppage;

	sis->max = isi.nr_pages;

	sis->pages = isi.nr_pages - 1;

	sis->highest_bit = isi.nr_pages - 1;

	return isi.nr_extents;

}

EXPORT_SYMBOL_GPL(iomap_swapfile_activate);