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Commit 58e8012c authored by David Sterba's avatar David Sterba
Browse files

btrfs: add optimized version of eb to eb copy 



Using copy_extent_buffer is suitable for copying betwenn buffers from an
arbitrary offset and deals with page boundaries. This is not necessary
when doing a full extent_buffer-to-extent_buffer copy. We can utilize
the copy_page helper as well.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent b159fa28

fs/btrfs/ctree.c

+2 −2
Original line number Diff line number Diff line
@@ -260,7 +260,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans, 
	if (IS_ERR(cow))

		return PTR_ERR(cow);



	copy_extent_buffer(cow, buf, 0, 0, cow->len);

	copy_extent_buffer_full(cow, buf);

	btrfs_set_header_bytenr(cow, cow->start);

	btrfs_set_header_generation(cow, trans->transid);

	btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
@@ -1129,7 +1129,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, 


	/* cow is set to blocking by btrfs_init_new_buffer */



	copy_extent_buffer(cow, buf, 0, 0, cow->len);

	copy_extent_buffer_full(cow, buf);

	btrfs_set_header_bytenr(cow, cow->start);

	btrfs_set_header_generation(cow, trans->transid);

	btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);

fs/btrfs/extent_io.c

+14 −0
Original line number Diff line number Diff line
@@ -5546,6 +5546,20 @@ void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start, 
	}

}



void copy_extent_buffer_full(struct extent_buffer *dst,

			     struct extent_buffer *src)

{

	int i;

	unsigned num_pages;



	ASSERT(dst->len == src->len);



	num_pages = num_extent_pages(dst->start, dst->len);

	for (i = 0; i < num_pages; i++)

		copy_page(page_address(dst->pages[i]),

				page_address(src->pages[i]));

}



void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,

			unsigned long dst_offset, unsigned long src_offset,

			unsigned long len)

fs/btrfs/extent_io.h

+2 −0
Original line number Diff line number Diff line
@@ -410,6 +410,8 @@ void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb, 
		const void *src);

void write_extent_buffer(struct extent_buffer *eb, const void *src,

			 unsigned long start, unsigned long len);

void copy_extent_buffer_full(struct extent_buffer *dst,

			     struct extent_buffer *src);

void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,

			unsigned long dst_offset, unsigned long src_offset,

			unsigned long len);