From 884b07d0f4f7e09d8312008fed04e01d9d2270dc Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Wed, 2 Dec 2020 14:48:04 +0800 Subject: [PATCH] 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: Goldwyn Rodrigues Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ctree.c | 3 +- fs/btrfs/ctree.h | 38 ++++++++++++++++++++++-- fs/btrfs/extent_io.c | 64 ++++++++++++++++++++++++----------------- fs/btrfs/struct-funcs.c | 18 ++++++------ 4 files changed, 85 insertions(+), 38 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index e5a0941c4bde..07810891e204 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -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); diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index c5ef29078954..98d6871b2295 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -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 diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 76e0b5ed75dd..6e3b72e63e42 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -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); - 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])); + 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); diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c index c46be27be700..8260f8bb3ff0 100644 --- a/fs/btrfs/struct-funcs.c +++ b/fs/btrfs/struct-funcs.c @@ -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; \