Commit cac06d84 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: introduce the skeleton of btrfs_subpage structure 



For sectorsize < page size support, we need a structure to record extra
status info for each sector of a page.

Introduce the skeleton structure, all subpage related code would go to
subpage.[ch].

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 62c053fb

fs/btrfs/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -27,7 +27,8 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \ 
	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \

	   reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \

	   uuid-tree.o props.o free-space-tree.o tree-checker.o space-info.o \

	   block-rsv.o delalloc-space.o block-group.o discard.o reflink.o

	   block-rsv.o delalloc-space.o block-group.o discard.o reflink.o \

	   subpage.o



btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o

btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o

fs/btrfs/subpage.c

0 → 100644
+43 −0
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// SPDX-License-Identifier: GPL-2.0



#include <linux/slab.h>

#include "ctree.h"

#include "subpage.h"



int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,

			 struct page *page, enum btrfs_subpage_type type)

{

	struct btrfs_subpage *subpage;



	/*

	 * We have cases like a dummy extent buffer page, which is not mappped

	 * and doesn't need to be locked.

	 */

	if (page->mapping)

		ASSERT(PageLocked(page));

	/* Either not subpage, or the page already has private attached */

	if (fs_info->sectorsize == PAGE_SIZE || PagePrivate(page))

		return 0;



	subpage = kzalloc(sizeof(struct btrfs_subpage), GFP_NOFS);

	if (!subpage)

		return -ENOMEM;



	spin_lock_init(&subpage->lock);

	attach_page_private(page, subpage);

	return 0;

}



void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info,

			  struct page *page)

{

	struct btrfs_subpage *subpage;



	/* Either not subpage, or already detached */

	if (fs_info->sectorsize == PAGE_SIZE || !PagePrivate(page))

		return;



	subpage = (struct btrfs_subpage *)detach_page_private(page);

	ASSERT(subpage);

	kfree(subpage);

}

fs/btrfs/subpage.h

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Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#ifndef BTRFS_SUBPAGE_H

#define BTRFS_SUBPAGE_H



#include <linux/spinlock.h>



/*

 * Maximum page size we support is 64K, minimum sector size is 4K, u16 bitmap

 * is sufficient. Regular bitmap_* is not used due to size reasons.

 */

#define BTRFS_SUBPAGE_BITMAP_SIZE	16



/*

 * Structure to trace status of each sector inside a page, attached to

 * page::private for both data and metadata inodes.

 */

struct btrfs_subpage {

	/* Common members for both data and metadata pages */

	spinlock_t lock;

};



enum btrfs_subpage_type {

	BTRFS_SUBPAGE_METADATA,

	BTRFS_SUBPAGE_DATA,

};



int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,

			 struct page *page, enum btrfs_subpage_type type);

void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info,

			  struct page *page);



#endif

fs/btrfs/super.c

+0 −1
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@@ -48,7 +48,6 @@ 
#include "tests/btrfs-tests.h"

#include "block-group.h"

#include "discard.h"



#include "qgroup.h"

#define CREATE_TRACE_POINTS

#include <trace/events/btrfs.h>