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From: Qu Wenruo <wqu@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 07/17] btrfs: make csum_tree_block() handle sectorsize smaller than page size
Date: Tue,  8 Sep 2020 15:52:20 +0800	[thread overview]
Message-ID: <20200908075230.86856-8-wqu@suse.com> (raw)
In-Reply-To: <20200908075230.86856-1-wqu@suse.com>

For subpage size support, we only need to handle the first page.

To make the code work for both cases, we modify the following behaviors:

- num_pages calcuation
  Instead of "nodesize >> PAGE_SHIFT", we go
  "DIV_ROUND_UP(nodesize, PAGE_SIZE)", this ensures we get at least one
  page for subpage size support, while still get the same result for
  reguar page size.

- The length for the first run
  Instead of PAGE_SIZE - BTRFS_CSUM_SIZE, we go min(PAGE_SIZE, nodesize)
  - BTRFS_CSUM_SIZE.
  This allows us to handle both cases well.

- The start location of the first run
  Instead of always use BTRFS_CSUM_SIZE as csum start position, add
  offset_in_page(eb->start) to get proper offset for both cases.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/disk-io.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f6bba7eb1fa1..62dbd9bbd381 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -257,16 +257,16 @@ struct extent_map *btree_get_extent(struct btrfs_inode *inode,
 static void csum_tree_block(struct extent_buffer *buf, u8 *result)
 {
 	struct btrfs_fs_info *fs_info = buf->fs_info;
-	const int num_pages = fs_info->nodesize >> PAGE_SHIFT;
+	const int num_pages = DIV_ROUND_UP(fs_info->nodesize, PAGE_SIZE);
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	char *kaddr;
 	int i;
 
 	shash->tfm = fs_info->csum_shash;
 	crypto_shash_init(shash);
-	kaddr = page_address(buf->pages[0]);
+	kaddr = page_address(buf->pages[0]) + offset_in_page(buf->start);
 	crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,
-			    PAGE_SIZE - BTRFS_CSUM_SIZE);
+		min_t(u32, PAGE_SIZE, fs_info->nodesize) - BTRFS_CSUM_SIZE);
 
 	for (i = 1; i < num_pages; i++) {
 		kaddr = page_address(buf->pages[i]);
-- 
2.28.0


  parent reply	other threads:[~2020-09-08  7:53 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-08  7:52 [PATCH 00/17] btrfs: add read-only support for subpage sector size Qu Wenruo
2020-09-08  7:52 ` [PATCH 01/17] btrfs: extent-io-tests: remove invalid tests Qu Wenruo
2020-09-09 12:26   ` Nikolay Borisov
2020-09-09 13:06     ` Qu Wenruo
2020-09-08  7:52 ` [PATCH 02/17] btrfs: calculate inline extent buffer page size based on page size Qu Wenruo
2020-09-11  9:56   ` Nikolay Borisov
2020-09-11 10:13     ` Qu Wenruo
2020-09-08  7:52 ` [PATCH 03/17] btrfs: remove the open-code to read disk-key Qu Wenruo
2020-09-11 10:07   ` Nikolay Borisov
2020-09-08  7:52 ` [PATCH 04/17] btrfs: make btrfs_fs_info::buffer_radix to take sector size devided values Qu Wenruo
2020-09-11 10:11   ` Nikolay Borisov
2020-09-11 10:15     ` Qu Wenruo
2020-09-08  7:52 ` [PATCH 05/17] btrfs: don't allow tree block to cross page boundary for subpage support Qu Wenruo
2020-09-11 10:26   ` Nikolay Borisov
2020-09-11 11:36     ` Qu Wenruo
2020-09-11 12:08       ` Nikolay Borisov
2020-09-08  7:52 ` [PATCH 06/17] btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors Qu Wenruo
2020-09-08  7:52 ` Qu Wenruo [this message]
2020-09-11 11:10   ` [PATCH 07/17] btrfs: make csum_tree_block() handle sectorsize smaller than page size Nikolay Borisov
2020-09-08  7:52 ` [PATCH 08/17] btrfs: refactor how we extract extent buffer from page for alloc_extent_buffer() Qu Wenruo
2020-09-11 11:14   ` Nikolay Borisov
2020-09-08  7:52 ` [PATCH 09/17] btrfs: refactor btrfs_release_extent_buffer_pages() Qu Wenruo
2020-09-11 11:17   ` Nikolay Borisov
2020-09-11 11:39     ` Qu Wenruo
2020-09-08  7:52 ` [PATCH 10/17] btrfs: add assert_spin_locked() for attach_extent_buffer_page() Qu Wenruo
2020-09-11 11:22   ` Nikolay Borisov
2020-09-08  7:52 ` [PATCH 11/17] btrfs: extract the extent buffer verification from btree_readpage_end_io_hook() Qu Wenruo
2020-09-11 13:00   ` Nikolay Borisov
2020-09-08  7:52 ` [PATCH 12/17] btrfs: remove the unnecessary parameter @start and @len for check_data_csum() Qu Wenruo
2020-09-11 13:50   ` Nikolay Borisov
2020-09-08  7:52 ` [PATCH 13/17] btrfs: extent_io: only require sector size alignment for page read Qu Wenruo
2020-09-11 13:55   ` Nikolay Borisov
2020-09-15  1:54     ` Qu Wenruo
2020-09-08  7:52 ` [PATCH 14/17] btrfs: make btrfs_readpage_end_io_hook() follow sector size Qu Wenruo
2020-09-09 17:34   ` Goldwyn Rodrigues
2020-09-10  0:05     ` Qu Wenruo
2020-09-10 14:26       ` Goldwyn Rodrigues
2020-09-08  7:52 ` [PATCH 15/17] btrfs: introduce subpage_eb_mapping for extent buffers Qu Wenruo
2020-09-08 10:22   ` kernel test robot
2020-09-08 14:24   ` Dan Carpenter
2020-09-08  7:52 ` [PATCH 16/17] btrfs: handle extent buffer verification proper for subpage size Qu Wenruo
2020-09-08  7:52 ` [PATCH 17/17] btrfs: allow RO mount of 4K sector size fs on 64K page system Qu Wenruo
2020-09-08  8:03 ` [PATCH 00/17] btrfs: add read-only support for subpage sector size Qu Wenruo
2020-09-11 10:24 ` Qu Wenruo

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