All of lore.kernel.org
 help / color / mirror / Atom feed
From: Qu Wenruo <wqu@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH v2 08/19] btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors
Date: Tue, 15 Sep 2020 13:35:21 +0800	[thread overview]
Message-ID: <20200915053532.63279-9-wqu@suse.com> (raw)
In-Reply-To: <20200915053532.63279-1-wqu@suse.com>

To support sectorsize < PAGE_SIZE case, we need to take extra care for
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 these:
- 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 works also fine.

- get_eb_page_offset()
  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()

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/ctree.h        | 38 ++++++++++++++++++++++--
 fs/btrfs/extent_io.c    | 66 ++++++++++++++++++++++++-----------------
 fs/btrfs/struct-funcs.c | 18 ++++++-----
 3 files changed, 85 insertions(+), 37 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9a72896bed2e..81d5a6cc97b5 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1448,14 +1448,15 @@ 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);			\
 	u##bits res = le##bits##_to_cpu(p->member);			\
 	return res;							\
 }									\
 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); \
 	p->member = cpu_to_le##bits(val);				\
 }
 
@@ -3241,6 +3242,39 @@ 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.
+ *
+ * Will handle both sectorsize == PAGE_SIZE and sectorsize < PAGE_SIZE cases.
+ *
+ * @eb:		The target extent buffer
+ * @start:	The offset inside the extent buffer
+ */
+static inline size_t get_eb_page_offset(const struct extent_buffer *eb,
+					unsigned long start)
+{
+	/*
+	 * 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 belongs to
+	 * the eb, thus we have to take the eb->start into consideration.
+	 */
+	return offset_in_page(start + eb->start);
+}
+
+static inline unsigned long get_eb_page_index(unsigned long start)
+{
+	/*
+	 * For sectorsize == PAGE_SIZE case, plain >> PAGE_SHIFT is enough.
+	 *
+	 * For sectorsize < PAGE_SIZE case, we only support 64K PAGE_SIZE,
+	 * and has ensured all tree blocks are contained in one page, thus
+	 * we always get index == 0.
+	 */
+	return start >> 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 9af972999a09..ba9cc864d9c0 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -5637,7 +5637,7 @@ 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 (start + len > eb->len) {
 		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
@@ -5646,7 +5646,7 @@ void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
 		return;
 	}
 
-	offset = offset_in_page(start);
+	offset = get_eb_page_offset(eb, start);
 
 	while (len > 0) {
 		page = eb->pages[i];
@@ -5671,13 +5671,13 @@ int read_extent_buffer_to_user(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_page_offset(eb, start);
 
 	while (len > 0) {
 		page = eb->pages[i];
@@ -5706,13 +5706,13 @@ 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;
 
 	WARN_ON(start > eb->len);
 	WARN_ON(start + len > eb->start + eb->len);
 
-	offset = offset_in_page(start);
+	offset = get_eb_page_offset(eb, start);
 
 	while (len > 0) {
 		page = eb->pages[i];
@@ -5738,7 +5738,7 @@ 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_page_offset(eb, 0);
 	memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
 			BTRFS_FSID_SIZE);
 }
@@ -5748,7 +5748,7 @@ 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_page_offset(eb, 0);
 	memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
 			BTRFS_FSID_SIZE);
 }
@@ -5761,12 +5761,12 @@ 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);
 
 	WARN_ON(start > eb->len);
 	WARN_ON(start + len > eb->start + eb->len);
 
-	offset = offset_in_page(start);
+	offset = get_eb_page_offset(eb, start);
 
 	while (len > 0) {
 		page = eb->pages[i];
@@ -5790,12 +5790,12 @@ 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);
 
 	WARN_ON(start > eb->len);
 	WARN_ON(start + len > eb->start + eb->len);
 
-	offset = offset_in_page(start);
+	offset = get_eb_page_offset(eb, start);
 
 	while (len > 0) {
 		page = eb->pages[i];
@@ -5819,10 +5819,22 @@ 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 {
+		unsigned long src_index = get_eb_page_index(src->start);
+		unsigned long dst_index = get_eb_page_index(dst->start);
+		size_t src_offset = get_eb_page_offset(src, 0);
+		size_t dst_offset = get_eb_page_offset(dst, 0);
+
+		ASSERT(src_index == 0 && dst_index == 0);
+		memcpy(page_address(dst->pages[dst_index]) + dst_offset,
+		       page_address(src->pages[src_index]) + src_offset,
+		       src->len);
+	}
 }
 
 void copy_extent_buffer(const struct extent_buffer *dst,
@@ -5835,11 +5847,11 @@ 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);
 
 	WARN_ON(src->len != dst_len);
 
-	offset = offset_in_page(dst_offset);
+	offset = get_eb_page_offset(dst, dst_offset);
 
 	while (len > 0) {
 		page = dst->pages[i];
@@ -5883,7 +5895,7 @@ 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);
@@ -6047,11 +6059,11 @@ void memcpy_extent_buffer(const struct extent_buffer *dst,
 	}
 
 	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_page_offset(dst, dst_offset);
+		src_off_in_page = get_eb_page_offset(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));
@@ -6097,11 +6109,11 @@ 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_page_offset(dst, dst_end);
+		src_off_in_page = get_eb_page_offset(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 079b059818e9..769901c2b3c9 100644
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -67,8 +67,9 @@ 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_page_offset(token->eb, 	\
+						     member_offset);	\
 	const int size = sizeof(u##bits);				\
 	u8 lebytes[sizeof(u##bits)];					\
 	const int part = PAGE_SIZE - oip;				\
@@ -95,8 +96,8 @@ 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_page_offset(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;				\
@@ -116,8 +117,9 @@ 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_page_offset(token->eb,		\
+						     member_offset);	\
 	const int size = sizeof(u##bits);				\
 	u8 lebytes[sizeof(u##bits)];					\
 	const int part = PAGE_SIZE - oip;				\
@@ -146,8 +148,8 @@ 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_page_offset(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;				\
-- 
2.28.0


  parent reply	other threads:[~2020-09-15  5:36 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15  5:35 [PATCH v2 00/19] btrfs: add read-only support for subpage sector size Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 01/19] btrfs: extent-io-tests: remove invalid tests Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 02/19] btrfs: remove the unnecessary parameter @start and @len for check_data_csum() Qu Wenruo
2020-09-15  8:39   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 03/19] btrfs: calculate inline extent buffer page size based on page size Qu Wenruo
2020-09-15  8:35   ` Nikolay Borisov
2020-09-15 10:05     ` Qu Wenruo
2020-09-15  8:40   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 04/19] btrfs: remove the open-code to read disk-key Qu Wenruo
2020-09-15  8:36   ` Nikolay Borisov
2020-09-15  8:40   ` Johannes Thumshirn
2020-09-16 16:01   ` David Sterba
2020-09-17  8:02     ` Qu Wenruo
2020-09-17 12:37       ` David Sterba
2020-09-17 13:15         ` Qu Wenruo
2020-09-17 22:41           ` David Sterba
2020-09-17 23:26             ` Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 05/19] btrfs: make btrfs_fs_info::buffer_radix to take sector size devided values Qu Wenruo
2020-09-15  8:27   ` Johannes Thumshirn
2020-09-15 10:04     ` Qu Wenruo
2020-09-15 10:12       ` Johannes Thumshirn
2020-09-15 17:40   ` kernel test robot
2020-09-15 17:40     ` kernel test robot
2020-09-15  5:35 ` [PATCH v2 06/19] btrfs: don't allow tree block to cross page boundary for subpage support Qu Wenruo
2020-09-15  8:37   ` Nikolay Borisov
2020-09-15 10:06     ` Qu Wenruo
2020-09-15  8:44   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 07/19] btrfs: update num_extent_pages() to support subpage sized extent buffer Qu Wenruo
2020-09-15  8:42   ` Johannes Thumshirn
2020-09-15 10:07     ` Qu Wenruo
2020-09-15 10:12       ` Johannes Thumshirn
2020-09-15 10:07     ` Qu Wenruo
2020-09-15  5:35 ` Qu Wenruo [this message]
2020-09-15  5:35 ` [PATCH v2 09/19] btrfs: make csum_tree_block() handle sectorsize smaller than page size Qu Wenruo
2020-09-15  8:47   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 10/19] btrfs: add assert_spin_locked() for attach_extent_buffer_page() Qu Wenruo
2020-09-15  8:52   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 11/19] btrfs: extract the extent buffer verification from btree_readpage_end_io_hook() Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 12/19] btrfs: extent_io: only require sector size alignment for page read Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 13/19] btrfs: make btrfs_readpage_end_io_hook() follow sector size Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 14/19] btrfs: make btree inode io_tree has its special owner Qu Wenruo
2020-09-16  9:28   ` Johannes Thumshirn
2020-09-16 16:06   ` David Sterba
2020-09-17  0:02     ` Qu Wenruo
2020-09-17 12:50       ` David Sterba
2020-09-18  8:18         ` Qu Wenruo
2020-09-22 14:06           ` David Sterba
2020-09-22 14:14   ` David Sterba
2020-09-15  5:35 ` [PATCH v2 15/19] btrfs: don't set extent_io_tree bits for btree inode at endio time Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 16/19] btrfs: use extent_io_tree to handle subpage extent buffer allocation Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 17/19] btrfs: implement subpage metadata read and its endio function Qu Wenruo
2020-09-15 18:49   ` kernel test robot
2020-09-16  8:47   ` kernel test robot
2020-09-16  8:47     ` kernel test robot
2020-09-15  5:35 ` [PATCH v2 18/19] btrfs: implement btree_readpage() and try_release_extent_buffer() for subpage Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 19/19] btrfs: allow RO mount of 4K sector size fs on 64K page system Qu Wenruo
2020-09-16  1:35 ` [PATCH v2 00/19] btrfs: add read-only support for subpage sector size Qu Wenruo
2020-09-16 16:18 ` Neal Gompa
2020-09-17  0:03   ` Qu Wenruo
2020-09-17  0:13     ` Neal Gompa
2020-09-17  0:24       ` Qu Wenruo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200915053532.63279-9-wqu@suse.com \
    --to=wqu@suse.com \
    --cc=linux-btrfs@vger.kernel.org \
    --cc=rgoldwyn@suse.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.