| Message ID | 4f450bbeec245479a3bc2b40d023d1979d622587.1582832619.git.dsterba@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Misc cleanups | expand |
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
On 2020/2/28 上午4:00, David Sterba wrote: > Thw whole point of csum_tree_block is to iterate over all extent buffer > pages and pass it to checksumming functions. The bytes where checksum is > stored must be skipped, thus map_private_extent_buffer. This complicates > further offset calculations. > > As the first page will be always present, checksum the relevant bytes > unconditionally and then do a simple iteration over the remaining pages. The new operation looks much better. Reviewed-by: Qu Wenruo <wqu@suse.com> Thanks, Qu > > Signed-off-by: David Sterba <dsterba@suse.com> > --- > fs/btrfs/disk-io.c | 32 ++++++++------------------------ > 1 file changed, 8 insertions(+), 24 deletions(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 3952e4a2f3d7..5f74eb69f2fe 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -259,38 +259,22 @@ struct extent_map *btree_get_extent(struct btrfs_inode *inode, > static int 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; > SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); > - unsigned long len; > - unsigned long cur_len; > - unsigned long offset = BTRFS_CSUM_SIZE; > char *kaddr; > - unsigned long map_start; > - unsigned long map_len; > - int err; > + int i; > > shash->tfm = fs_info->csum_shash; > crypto_shash_init(shash); > + kaddr = page_address(buf->pages[0]); > + crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE, > + PAGE_SIZE - BTRFS_CSUM_SIZE); > > - len = buf->len - offset; > - > - while (len > 0) { > - /* > - * Note: we don't need to check for the err == 1 case here, as > - * with the given combination of 'start = BTRFS_CSUM_SIZE (32)' > - * and 'min_len = 32' and the currently implemented mapping > - * algorithm we cannot cross a page boundary. > - */ > - err = map_private_extent_buffer(buf, offset, 32, > - &kaddr, &map_start, &map_len); > - if (WARN_ON(err)) > - return err; > - cur_len = min(len, map_len - (offset - map_start)); > - crypto_shash_update(shash, kaddr + offset - map_start, cur_len); > - len -= cur_len; > - offset += cur_len; > + for (i = 1; i < num_pages; i++) { > + kaddr = page_address(buf->pages[i]); > + crypto_shash_update(shash, kaddr, PAGE_SIZE); > } > memset(result, 0, BTRFS_CSUM_SIZE); > - > crypto_shash_final(shash, result); > > return 0; >
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 3952e4a2f3d7..5f74eb69f2fe 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -259,38 +259,22 @@ struct extent_map *btree_get_extent(struct btrfs_inode *inode, static int 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; SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); - unsigned long len; - unsigned long cur_len; - unsigned long offset = BTRFS_CSUM_SIZE; char *kaddr; - unsigned long map_start; - unsigned long map_len; - int err; + int i; shash->tfm = fs_info->csum_shash; crypto_shash_init(shash); + kaddr = page_address(buf->pages[0]); + crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE, + PAGE_SIZE - BTRFS_CSUM_SIZE); - len = buf->len - offset; - - while (len > 0) { - /* - * Note: we don't need to check for the err == 1 case here, as - * with the given combination of 'start = BTRFS_CSUM_SIZE (32)' - * and 'min_len = 32' and the currently implemented mapping - * algorithm we cannot cross a page boundary. - */ - err = map_private_extent_buffer(buf, offset, 32, - &kaddr, &map_start, &map_len); - if (WARN_ON(err)) - return err; - cur_len = min(len, map_len - (offset - map_start)); - crypto_shash_update(shash, kaddr + offset - map_start, cur_len); - len -= cur_len; - offset += cur_len; + for (i = 1; i < num_pages; i++) { + kaddr = page_address(buf->pages[i]); + crypto_shash_update(shash, kaddr, PAGE_SIZE); } memset(result, 0, BTRFS_CSUM_SIZE); - crypto_shash_final(shash, result); return 0;
Thw whole point of csum_tree_block is to iterate over all extent buffer pages and pass it to checksumming functions. The bytes where checksum is stored must be skipped, thus map_private_extent_buffer. This complicates further offset calculations. As the first page will be always present, checksum the relevant bytes unconditionally and then do a simple iteration over the remaining pages. Signed-off-by: David Sterba <dsterba@suse.com> --- fs/btrfs/disk-io.c | 32 ++++++++------------------------ 1 file changed, 8 insertions(+), 24 deletions(-)