Commit 884b07d0 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors 



To support sectorsize < PAGE_SIZE case, we need to take extra care of
extent buffer accessors.

Since sectorsize is smaller than PAGE_SIZE, one page can contain
multiple tree blocks, we must use eb->start to determine the real offset
to read/write for extent buffer accessors.

This patch introduces two helpers to do this:

- get_eb_page_index()
  This is to calculate the index to access extent_buffer::pages.
  It's just a simple wrapper around "start >> PAGE_SHIFT".

  For sectorsize == PAGE_SIZE case, nothing is changed.
  For sectorsize < PAGE_SIZE case, we always get index as 0, and
  the existing page shift also works.

- get_eb_offset_in_page()
  This is to calculate the offset to access extent_buffer::pages.
  This needs to take extent_buffer::start into consideration.

  For sectorsize == PAGE_SIZE case, extent_buffer::start is always
  aligned to PAGE_SIZE, thus adding extent_buffer::start to
  offset_in_page() won't change the result.
  For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives
  us the correct offset to access.

This patch will touch the following parts to cover all extent buffer
accessors:

- BTRFS_SETGET_HEADER_FUNCS()
- read_extent_buffer()
- read_extent_buffer_to_user()
- memcmp_extent_buffer()
- write_extent_buffer_chunk_tree_uuid()
- write_extent_buffer_fsid()
- write_extent_buffer()
- memzero_extent_buffer()
- copy_extent_buffer_full()
- copy_extent_buffer()
- memcpy_extent_buffer()
- memmove_extent_buffer()
- btrfs_get_token_##bits()
- btrfs_get_##bits()
- btrfs_set_token_##bits()
- btrfs_set_##bits()
- generic_bin_search()

Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.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 4a3dc938

fs/btrfs/ctree.c

+2 −1
Original line number Diff line number Diff line
@@ -1683,9 +1683,10 @@ static noinline int generic_bin_search(struct extent_buffer *eb, 
		oip = offset_in_page(offset);



		if (oip + key_size <= PAGE_SIZE) {

			const unsigned long idx = offset >> PAGE_SHIFT;

			const unsigned long idx = get_eb_page_index(offset);

			char *kaddr = page_address(eb->pages[idx]);



			oip = get_eb_offset_in_page(eb, offset);

			tmp = (struct btrfs_disk_key *)(kaddr + oip);

		} else {

			read_extent_buffer(eb, &unaligned, offset, key_size);

fs/btrfs/ctree.h

+36 −2
Original line number Diff line number Diff line
@@ -1552,13 +1552,14 @@ static inline void btrfs_set_token_##name(struct btrfs_map_token *token,\ 
#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits)		\

static inline u##bits btrfs_##name(const struct extent_buffer *eb)	\

{									\

	const type *p = page_address(eb->pages[0]);			\

	const type *p = page_address(eb->pages[0]) +			\

			offset_in_page(eb->start);			\

	return get_unaligned_le##bits(&p->member);			\

}									\

static inline void btrfs_set_##name(const struct extent_buffer *eb,	\

				    u##bits val)			\

{									\

	type *p = page_address(eb->pages[0]);				\

	type *p = page_address(eb->pages[0]) + offset_in_page(eb->start); \

	put_unaligned_le##bits(val, &p->member);			\

}
@@ -3366,6 +3367,39 @@ static inline void assertfail(const char *expr, const char* file, int line) { } 
#define ASSERT(expr)	(void)(expr)

#endif



/*

 * Get the correct offset inside the page of extent buffer.

 *

 * @eb:		target extent buffer

 * @start:	offset inside the extent buffer

 *

 * Will handle both sectorsize == PAGE_SIZE and sectorsize < PAGE_SIZE cases.

 */

static inline size_t get_eb_offset_in_page(const struct extent_buffer *eb,

					   unsigned long offset)

{

	/*

	 * For sectorsize == PAGE_SIZE case, eb->start will always be aligned

	 * to PAGE_SIZE, thus adding it won't cause any difference.

	 *

	 * For sectorsize < PAGE_SIZE, we must only read the data that belongs

	 * to the eb, thus we have to take the eb->start into consideration.

	 */

	return offset_in_page(offset + eb->start);

}



static inline unsigned long get_eb_page_index(unsigned long offset)

{

	/*

	 * For sectorsize == PAGE_SIZE case, plain >> PAGE_SHIFT is enough.

	 *

	 * For sectorsize < PAGE_SIZE case, we only support 64K PAGE_SIZE,

	 * and have ensured that all tree blocks are contained in one page,

	 * thus we always get index == 0.

	 */

	return offset >> PAGE_SHIFT;

}



/*

 * Use that for functions that are conditionally exported for sanity tests but

 * otherwise static

fs/btrfs/extent_io.c

+37 −27
Original line number Diff line number Diff line
@@ -5703,12 +5703,12 @@ void read_extent_buffer(const struct extent_buffer *eb, void *dstv, 
	struct page *page;

	char *kaddr;

	char *dst = (char *)dstv;

	unsigned long i = start >> PAGE_SHIFT;

	unsigned long i = get_eb_page_index(start);



	if (check_eb_range(eb, start, len))

		return;



	offset = offset_in_page(start);

	offset = get_eb_offset_in_page(eb, start);



	while (len > 0) {

		page = eb->pages[i];
@@ -5733,13 +5733,13 @@ int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb, 
	struct page *page;

	char *kaddr;

	char __user *dst = (char __user *)dstv;

	unsigned long i = start >> PAGE_SHIFT;

	unsigned long i = get_eb_page_index(start);

	int ret = 0;



	WARN_ON(start > eb->len);

	WARN_ON(start + len > eb->start + eb->len);



	offset = offset_in_page(start);

	offset = get_eb_offset_in_page(eb, start);



	while (len > 0) {

		page = eb->pages[i];
@@ -5768,13 +5768,13 @@ int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv, 
	struct page *page;

	char *kaddr;

	char *ptr = (char *)ptrv;

	unsigned long i = start >> PAGE_SHIFT;

	unsigned long i = get_eb_page_index(start);

	int ret = 0;



	if (check_eb_range(eb, start, len))

		return -EINVAL;



	offset = offset_in_page(start);

	offset = get_eb_offset_in_page(eb, start);



	while (len > 0) {

		page = eb->pages[i];
@@ -5800,7 +5800,7 @@ void write_extent_buffer_chunk_tree_uuid(const struct extent_buffer *eb, 
	char *kaddr;



	WARN_ON(!PageUptodate(eb->pages[0]));

	kaddr = page_address(eb->pages[0]);

	kaddr = page_address(eb->pages[0]) + get_eb_offset_in_page(eb, 0);

	memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,

			BTRFS_FSID_SIZE);

}
@@ -5810,7 +5810,7 @@ void write_extent_buffer_fsid(const struct extent_buffer *eb, const void *srcv) 
	char *kaddr;



	WARN_ON(!PageUptodate(eb->pages[0]));

	kaddr = page_address(eb->pages[0]);

	kaddr = page_address(eb->pages[0]) + get_eb_offset_in_page(eb, 0);

	memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,

			BTRFS_FSID_SIZE);

}
@@ -5823,12 +5823,12 @@ void write_extent_buffer(const struct extent_buffer *eb, const void *srcv, 
	struct page *page;

	char *kaddr;

	char *src = (char *)srcv;

	unsigned long i = start >> PAGE_SHIFT;

	unsigned long i = get_eb_page_index(start);



	if (check_eb_range(eb, start, len))

		return;



	offset = offset_in_page(start);

	offset = get_eb_offset_in_page(eb, start);



	while (len > 0) {

		page = eb->pages[i];
@@ -5852,12 +5852,12 @@ void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start, 
	size_t offset;

	struct page *page;

	char *kaddr;

	unsigned long i = start >> PAGE_SHIFT;

	unsigned long i = get_eb_page_index(start);



	if (check_eb_range(eb, start, len))

		return;



	offset = offset_in_page(start);

	offset = get_eb_offset_in_page(eb, start);



	while (len > 0) {

		page = eb->pages[i];
@@ -5881,10 +5881,20 @@ void copy_extent_buffer_full(const struct extent_buffer *dst, 


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



	if (dst->fs_info->sectorsize == PAGE_SIZE) {

		num_pages = num_extent_pages(dst);

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

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

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

	} else {

		size_t src_offset = get_eb_offset_in_page(src, 0);

		size_t dst_offset = get_eb_offset_in_page(dst, 0);



		ASSERT(src->fs_info->sectorsize < PAGE_SIZE);

		memcpy(page_address(dst->pages[0]) + dst_offset,

		       page_address(src->pages[0]) + src_offset,

		       src->len);

	}

}



void copy_extent_buffer(const struct extent_buffer *dst,
@@ -5897,7 +5907,7 @@ void copy_extent_buffer(const struct extent_buffer *dst, 
	size_t offset;

	struct page *page;

	char *kaddr;

	unsigned long i = dst_offset >> PAGE_SHIFT;

	unsigned long i = get_eb_page_index(dst_offset);



	if (check_eb_range(dst, dst_offset, len) ||

	    check_eb_range(src, src_offset, len))
@@ -5905,7 +5915,7 @@ void copy_extent_buffer(const struct extent_buffer *dst, 


	WARN_ON(src->len != dst_len);



	offset = offset_in_page(dst_offset);

	offset = get_eb_offset_in_page(dst, dst_offset);



	while (len > 0) {

		page = dst->pages[i];
@@ -5949,7 +5959,7 @@ static inline void eb_bitmap_offset(const struct extent_buffer *eb, 
	 * the bitmap item in the extent buffer + the offset of the byte in the

	 * bitmap item.

	 */

	offset = start + byte_offset;

	offset = start + offset_in_page(eb->start) + byte_offset;



	*page_index = offset >> PAGE_SHIFT;

	*page_offset = offset_in_page(offset);
@@ -6103,11 +6113,11 @@ void memcpy_extent_buffer(const struct extent_buffer *dst, 
		return;



	while (len > 0) {

		dst_off_in_page = offset_in_page(dst_offset);

		src_off_in_page = offset_in_page(src_offset);

		dst_off_in_page = get_eb_offset_in_page(dst, dst_offset);

		src_off_in_page = get_eb_offset_in_page(dst, src_offset);



		dst_i = dst_offset >> PAGE_SHIFT;

		src_i = src_offset >> PAGE_SHIFT;

		dst_i = get_eb_page_index(dst_offset);

		src_i = get_eb_page_index(src_offset);



		cur = min(len, (unsigned long)(PAGE_SIZE -

					       src_off_in_page));
@@ -6143,11 +6153,11 @@ void memmove_extent_buffer(const struct extent_buffer *dst, 
		return;

	}

	while (len > 0) {

		dst_i = dst_end >> PAGE_SHIFT;

		src_i = src_end >> PAGE_SHIFT;

		dst_i = get_eb_page_index(dst_end);

		src_i = get_eb_page_index(src_end);



		dst_off_in_page = offset_in_page(dst_end);

		src_off_in_page = offset_in_page(src_end);

		dst_off_in_page = get_eb_offset_in_page(dst, dst_end);

		src_off_in_page = get_eb_offset_in_page(dst, src_end);



		cur = min_t(unsigned long, len, src_off_in_page + 1);

		cur = min(cur, dst_off_in_page + 1);

fs/btrfs/struct-funcs.c

+10 −8
Original line number Diff line number Diff line
@@ -57,8 +57,9 @@ u##bits btrfs_get_token_##bits(struct btrfs_map_token *token, \ 
			       const void *ptr, unsigned long off)	\

{									\

	const unsigned long member_offset = (unsigned long)ptr + off;	\

	const unsigned long idx = member_offset >> PAGE_SHIFT;		\

	const unsigned long oip = offset_in_page(member_offset);	\

	const unsigned long idx = get_eb_page_index(member_offset);	\

	const unsigned long oip = get_eb_offset_in_page(token->eb,	\

							member_offset);	\

	const int size = sizeof(u##bits);				\

	u8 lebytes[sizeof(u##bits)];					\

	const int part = PAGE_SIZE - oip;				\
@@ -85,8 +86,8 @@ u##bits btrfs_get_##bits(const struct extent_buffer *eb, \ 
			 const void *ptr, unsigned long off)		\

{									\

	const unsigned long member_offset = (unsigned long)ptr + off;	\

	const unsigned long oip = offset_in_page(member_offset);	\

	const unsigned long idx = member_offset >> PAGE_SHIFT;		\

	const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \

	const unsigned long idx = get_eb_page_index(member_offset);	\

	char *kaddr = page_address(eb->pages[idx]);			\

	const int size = sizeof(u##bits);				\

	const int part = PAGE_SIZE - oip;				\
@@ -106,8 +107,9 @@ void btrfs_set_token_##bits(struct btrfs_map_token *token, \ 
			    u##bits val)				\

{									\

	const unsigned long member_offset = (unsigned long)ptr + off;	\

	const unsigned long idx = member_offset >> PAGE_SHIFT;		\

	const unsigned long oip = offset_in_page(member_offset);	\

	const unsigned long idx = get_eb_page_index(member_offset);	\

	const unsigned long oip = get_eb_offset_in_page(token->eb,	\

							member_offset);	\

	const int size = sizeof(u##bits);				\

	u8 lebytes[sizeof(u##bits)];					\

	const int part = PAGE_SIZE - oip;				\
@@ -136,8 +138,8 @@ void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \ 
		      unsigned long off, u##bits val)			\

{									\

	const unsigned long member_offset = (unsigned long)ptr + off;	\

	const unsigned long oip = offset_in_page(member_offset);	\

	const unsigned long idx = member_offset >> PAGE_SHIFT;		\

	const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \

	const unsigned long idx = get_eb_page_index(member_offset);	\

	char *kaddr = page_address(eb->pages[idx]);			\

	const int size = sizeof(u##bits);				\

	const int part = PAGE_SIZE - oip;				\