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Commit d1782a3b authored by Alasdair G Kergon's avatar Alasdair G Kergon Committed by Linus Torvalds
Browse files

[PATCH] device-mapper: store bdev while frozen 



Store the struct block_device while device is frozen, saving us one call to
bdget_disk().

Signed-Off-By: default avatarAlasdair G Kergon <agk@redhat.com>
From: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d17d7fa4

drivers/md/dm.c

+8 −15
Original line number Diff line number Diff line
@@ -97,6 +97,7 @@ struct mapped_device { 
	 * freeze/thaw support require holding onto a super block

	 */

	struct super_block *frozen_sb;

	struct block_device *frozen_bdev;

};



#define MIN_IOS 256
@@ -990,19 +991,17 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table) 
 */

static int __lock_fs(struct mapped_device *md)

{

	struct block_device *bdev;



	if (test_and_set_bit(DMF_FS_LOCKED, &md->flags))

		return 0;



	bdev = bdget_disk(md->disk, 0);

	if (!bdev) {

	md->frozen_bdev = bdget_disk(md->disk, 0);

	if (!md->frozen_bdev) {

		DMWARN("bdget failed in __lock_fs");

		return -ENOMEM;

	}



	WARN_ON(md->frozen_sb);

	md->frozen_sb = freeze_bdev(bdev);

	md->frozen_sb = freeze_bdev(md->frozen_bdev);

	/* don't bdput right now, we don't want the bdev

	 * to go away while it is locked.  We'll bdput

	 * in __unlock_fs
@@ -1012,21 +1011,15 @@ static int __lock_fs(struct mapped_device *md) 


static int __unlock_fs(struct mapped_device *md)

{

	struct block_device *bdev;



	if (!test_and_clear_bit(DMF_FS_LOCKED, &md->flags))

		return 0;



	bdev = bdget_disk(md->disk, 0);

	if (!bdev) {

		DMWARN("bdget failed in __unlock_fs");

		return -ENOMEM;

	}

	thaw_bdev(md->frozen_bdev, md->frozen_sb);

	bdput(md->frozen_bdev);



	thaw_bdev(bdev, md->frozen_sb);

	md->frozen_sb = NULL;

	bdput(bdev);

	bdput(bdev);

	md->frozen_bdev = NULL;



	return 0;

}