Commit b335eab8 authored by Nikolay Borisov's avatar Nikolay Borisov Committed by David Sterba
Browse files

btrfs: make btrfs_read_disk_super return struct btrfs_disk_super 



Instead of returning both the page and the super block structure, make
btrfs_read_disk_super just return a pointer to struct btrfs_disk_super.
As a result the function signature is simplified. Also,
read_cache_page_gfp can never return NULL so check its return value only
for IS_ERR.

Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent a7571232

fs/btrfs/volumes.c

+23 −24
Original line number Diff line number Diff line
@@ -1251,49 +1251,48 @@ void btrfs_release_disk_super(struct btrfs_super_block *super) 
	put_page(page);

}



static int btrfs_read_disk_super(struct block_device *bdev, u64 bytenr,

				 struct page **page,

				 struct btrfs_super_block **disk_super)

static struct btrfs_super_block *btrfs_read_disk_super(struct block_device *bdev,

						       u64 bytenr)

{

	struct btrfs_super_block *disk_super;

	struct page *page;

	void *p;

	pgoff_t index;



	/* make sure our super fits in the device */

	if (bytenr + PAGE_SIZE >= i_size_read(bdev->bd_inode))

		return 1;

		return ERR_PTR(-EINVAL);



	/* make sure our super fits in the page */

	if (sizeof(**disk_super) > PAGE_SIZE)

		return 1;

	if (sizeof(*disk_super) > PAGE_SIZE)

		return ERR_PTR(-EINVAL);



	/* make sure our super doesn't straddle pages on disk */

	index = bytenr >> PAGE_SHIFT;

	if ((bytenr + sizeof(**disk_super) - 1) >> PAGE_SHIFT != index)

		return 1;

	if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_SHIFT != index)

		return ERR_PTR(-EINVAL);



	/* pull in the page with our super */

	*page = read_cache_page_gfp(bdev->bd_inode->i_mapping,

				   index, GFP_KERNEL);

	page = read_cache_page_gfp(bdev->bd_inode->i_mapping, index, GFP_KERNEL);



	if (IS_ERR(*page))

		return 1;

	if (IS_ERR(page))

		return ERR_CAST(page);



	p = page_address(*page);

	p = page_address(page);



	/* align our pointer to the offset of the super block */

	*disk_super = p + offset_in_page(bytenr);

	disk_super = p + offset_in_page(bytenr);



	if (btrfs_super_bytenr(*disk_super) != bytenr ||

	    btrfs_super_magic(*disk_super) != BTRFS_MAGIC) {

	if (btrfs_super_bytenr(disk_super) != bytenr ||

	    btrfs_super_magic(disk_super) != BTRFS_MAGIC) {

		btrfs_release_disk_super(p);

		return 1;

		return ERR_PTR(-EINVAL);

	}



	if ((*disk_super)->label[0] &&

		(*disk_super)->label[BTRFS_LABEL_SIZE - 1])

		(*disk_super)->label[BTRFS_LABEL_SIZE - 1] = '\0';

	if (disk_super->label[0] && disk_super->label[BTRFS_LABEL_SIZE - 1])

		disk_super->label[BTRFS_LABEL_SIZE - 1] = 0;



	return 0;

	return disk_super;

}



int btrfs_forget_devices(const char *path)
@@ -1319,7 +1318,6 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags, 
	bool new_device_added = false;

	struct btrfs_device *device = NULL;

	struct block_device *bdev;

	struct page *page;

	u64 bytenr;



	lockdep_assert_held(&uuid_mutex);
@@ -1337,8 +1335,9 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags, 
	if (IS_ERR(bdev))

		return ERR_CAST(bdev);



	if (btrfs_read_disk_super(bdev, bytenr, &page, &disk_super)) {

		device = ERR_PTR(-EINVAL);

	disk_super = btrfs_read_disk_super(bdev, bytenr);

	if (IS_ERR(disk_super)) {

		device = ERR_CAST(disk_super);

		goto error_bdev_put;

	}

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