From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:27296 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946113AbbHGSal (ORCPT ); Fri, 7 Aug 2015 14:30:41 -0400 Message-ID: <55C4F93D.3010605@fb.com> Date: Fri, 7 Aug 2015 14:30:21 -0400 From: Josef Bacik MIME-Version: 1.0 To: Chandan Rajendra , CC: , , , , Subject: Re: [PATCH V2 02/11] Btrfs: Compute and look up csums based on sectorsized blocks References: <1438931158-20888-1-git-send-email-chandan@linux.vnet.ibm.com> <1438931158-20888-3-git-send-email-chandan@linux.vnet.ibm.com> In-Reply-To: <1438931158-20888-3-git-send-email-chandan@linux.vnet.ibm.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 08/07/2015 03:05 AM, Chandan Rajendra wrote: > Checksums are applicable to sectorsize units. The current code uses > bio->bv_len units to compute and look up checksums. This works on machines > where sectorsize == PAGE_SIZE. This patch makes the checksum computation and > look up code to work with sectorsize units. > > Reviewed-by: Liu Bo > Signed-off-by: Chandan Rajendra > --- > fs/btrfs/file-item.c | 90 +++++++++++++++++++++++++++++++++------------------- > 1 file changed, 57 insertions(+), 33 deletions(-) > > diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c > index 58ece65..d752051 100644 > --- a/fs/btrfs/file-item.c > +++ b/fs/btrfs/file-item.c > @@ -172,6 +172,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, > u64 item_start_offset = 0; > u64 item_last_offset = 0; > u64 disk_bytenr; > + u64 page_bytes_left; > u32 diff; > int nblocks; > int bio_index = 0; > @@ -220,6 +221,8 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, > disk_bytenr = (u64)bio->bi_iter.bi_sector << 9; > if (dio) > offset = logical_offset; > + > + page_bytes_left = bvec->bv_len; > while (bio_index < bio->bi_vcnt) { > if (!dio) > offset = page_offset(bvec->bv_page) + bvec->bv_offset; > @@ -243,7 +246,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, > if (BTRFS_I(inode)->root->root_key.objectid == > BTRFS_DATA_RELOC_TREE_OBJECTID) { > set_extent_bits(io_tree, offset, > - offset + bvec->bv_len - 1, > + offset + root->sectorsize - 1, > EXTENT_NODATASUM, GFP_NOFS); > } else { > btrfs_info(BTRFS_I(inode)->root->fs_info, > @@ -281,11 +284,17 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, > found: > csum += count * csum_size; > nblocks -= count; > - bio_index += count; > + > while (count--) { > - disk_bytenr += bvec->bv_len; > - offset += bvec->bv_len; > - bvec++; > + disk_bytenr += root->sectorsize; > + offset += root->sectorsize; > + page_bytes_left -= root->sectorsize; > + if (!page_bytes_left) { > + bio_index++; > + bvec++; > + page_bytes_left = bvec->bv_len; > + } > + > } > } > btrfs_free_path(path); > @@ -432,6 +441,8 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, > struct bio_vec *bvec = bio->bi_io_vec; > int bio_index = 0; > int index; > + int nr_sectors; > + int i; > unsigned long total_bytes = 0; > unsigned long this_sum_bytes = 0; > u64 offset; > @@ -459,41 +470,54 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, > if (!contig) > offset = page_offset(bvec->bv_page) + bvec->bv_offset; > > - if (offset >= ordered->file_offset + ordered->len || > - offset < ordered->file_offset) { > - unsigned long bytes_left; > - sums->len = this_sum_bytes; > - this_sum_bytes = 0; > - btrfs_add_ordered_sum(inode, ordered, sums); > - btrfs_put_ordered_extent(ordered); > + data = kmap_atomic(bvec->bv_page); > I don't think we can have something kmap_atomic()'ed and then do allocations under it right? That's why we only kmap_atomic(), do the copy, and then unmap, unless I'm forgetting something? Thanks, Josef