From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp06.in.ibm.com ([122.248.162.6]:47626 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753029AbaCLOVW (ORCPT ); Wed, 12 Mar 2014 10:21:22 -0400 Received: from /spool/local by e28smtp06.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 12 Mar 2014 19:51:19 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 7C6FF125803E for ; Wed, 12 Mar 2014 19:53:31 +0530 (IST) Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s2CELJPV31916058 for ; Wed, 12 Mar 2014 19:51:20 +0530 Received: from d28av03.in.ibm.com (localhost [127.0.0.1]) by d28av03.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s2CELF7c009600 for ; Wed, 12 Mar 2014 19:51:16 +0530 From: Chandan Rajendra To: linux-btrfs@vger.kernel.org Cc: Chandan Rajendra , aneesh.kumar@linux.vnet.ibm.com Subject: [PATCH 1/6] Btrfs: subpagesize-blocksize: Get rid of whole page reads. Date: Wed, 12 Mar 2014 19:50:28 +0530 Message-Id: <1394634033-2528-2-git-send-email-chandan@linux.vnet.ibm.com> In-Reply-To: <1394634033-2528-1-git-send-email-chandan@linux.vnet.ibm.com> References: <1394634033-2528-1-git-send-email-chandan@linux.vnet.ibm.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: bio_vec->{bv_offset, bv_len} cannot be relied upon by the end bio functions to track the file offset range operated on by the bio. Hence this patch adds two new members to 'struct btrfs_io_bio' to track the file offset range. This patch also brings back check_page_locked() to reliably unlock pages in readpage's end bio function. Signed-off-by: Chandan Rajendra --- fs/btrfs/extent_io.c | 122 +++++++++++++++++++++++++++++++++------------------ fs/btrfs/volumes.h | 3 ++ 2 files changed, 82 insertions(+), 43 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index fbe501d..5a65aee 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1943,15 +1943,31 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end, * helper function to set a given page up to date if all the * extents in the tree for that page are up to date */ -static void check_page_uptodate(struct extent_io_tree *tree, struct page *page) +static void check_page_uptodate(struct extent_io_tree *tree, struct page *page, + struct extent_state *cached) { u64 start = page_offset(page); u64 end = start + PAGE_CACHE_SIZE - 1; - if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL)) + if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, cached)) SetPageUptodate(page); } /* + * helper function to unlock a page if all the extents in the tree + * for that page are unlocked + */ +static void check_page_locked(struct extent_io_tree *tree, struct page *page) +{ + u64 start = page_offset(page); + u64 end = start + PAGE_CACHE_SIZE - 1; + + if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) { + unlock_page(page); + } +} + + +/* * When IO fails, either with EIO or csum verification fails, we * try other mirrors that might have a good copy of the data. This * io_failure_record is used to record state as we go through all the @@ -2414,16 +2430,33 @@ static void end_bio_extent_writepage(struct bio *bio, int err) bio_put(bio); } -static void -endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len, - int uptodate) +static void unlock_extent_and_page(struct address_space *mapping, + struct extent_io_tree *tree, + struct btrfs_io_bio *io_bio) { - struct extent_state *cached = NULL; - u64 end = start + len - 1; + pgoff_t index; + u64 offset, len; + /* + * This btrfs_io_bio may span multiple pages. + * We need to unlock the pages convered by them + * if we got endio callback for all the blocks in the page. + * btrfs_io_bio also contain "contigous blocks of the file" + * look at submit_extent_page for more details. + */ - if (uptodate && tree->track_uptodate) - set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC); - unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC); + offset = io_bio->start_offset; + len = io_bio->len; + unlock_extent(tree, offset, offset + len - 1); + + index = offset >> PAGE_CACHE_SHIFT; + while (offset < io_bio->start_offset + len) { + struct page *page; + page = find_get_page(mapping, index); + check_page_locked(tree, page); + page_cache_release(page); + index++; + offset += PAGE_CACHE_SIZE; + } } /* @@ -2443,13 +2476,13 @@ static void end_bio_extent_readpage(struct bio *bio, int err) struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1; struct bio_vec *bvec = bio->bi_io_vec; struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); + struct address_space *mapping = bio->bi_io_vec->bv_page->mapping; struct extent_io_tree *tree; + struct extent_state *cached = NULL; u64 offset = 0; u64 start; u64 end; u64 len; - u64 extent_start = 0; - u64 extent_len = 0; int mirror; int ret; @@ -2482,8 +2515,8 @@ static void end_bio_extent_readpage(struct bio *bio, int err) bvec->bv_offset, bvec->bv_len); } - start = page_offset(page); - end = start + bvec->bv_offset + bvec->bv_len - 1; + start = page_offset(page) + bvec->bv_offset; + end = start + bvec->bv_len - 1; len = bvec->bv_len; if (++bvec <= bvec_end) @@ -2540,40 +2573,24 @@ readpage_ok: offset = i_size & (PAGE_CACHE_SIZE-1); if (page->index == end_index && offset) zero_user_segment(page, offset, PAGE_CACHE_SIZE); - SetPageUptodate(page); + if (tree->track_uptodate) + set_extent_uptodate(tree, start, end, &cached, + GFP_ATOMIC); } else { ClearPageUptodate(page); SetPageError(page); } - unlock_page(page); - offset += len; - if (unlikely(!uptodate)) { - if (extent_len) { - endio_readpage_release_extent(tree, - extent_start, - extent_len, 1); - extent_start = 0; - extent_len = 0; - } - endio_readpage_release_extent(tree, start, - end - start + 1, 0); - } else if (!extent_len) { - extent_start = start; - extent_len = end + 1 - start; - } else if (extent_start + extent_len == start) { - extent_len += end + 1 - start; - } else { - endio_readpage_release_extent(tree, extent_start, - extent_len, uptodate); - extent_start = start; - extent_len = end + 1 - start; - } + offset += len; + /* + * Check whether the page in the bvec can be marked uptodate + */ + check_page_uptodate(tree, page, cached); } while (bvec <= bvec_end); - - if (extent_len) - endio_readpage_release_extent(tree, extent_start, extent_len, - uptodate); + /* + * Unlock the btrfs_bio and associated page + */ + unlock_extent_and_page(mapping, tree, io_bio); if (io_bio->end_io) io_bio->end_io(io_bio, err); bio_put(bio); @@ -2700,6 +2717,18 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree, else contig = bio_end_sector(bio) == sector; + if (contig) { + /* + * Check whether we are contig if file offsets. + * We should mostly be for readpage/readpages + * We need to do this because we use btrfs_io_bio + * start_offset and len to unlock in endio routines. + */ + if ((page_offset(page) + offset) != + (btrfs_io_bio(bio)->start_offset + + btrfs_io_bio(bio)->len)) + contig = 0; + } if (prev_bio_flags != bio_flags || !contig || merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) || bio_add_page(bio, page, page_size, offset) < page_size) { @@ -2709,6 +2738,11 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree, return ret; bio = NULL; } else { + /* + * update btrfs_io_bio len. So that we can unlock + * correctly in end_io callback. + */ + btrfs_io_bio(bio)->len += page_size; return 0; } } @@ -2724,6 +2758,8 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree, bio_add_page(bio, page, page_size, offset); bio->bi_end_io = end_io_func; bio->bi_private = tree; + btrfs_io_bio(bio)->start_offset = page_offset(page) + offset; + btrfs_io_bio(bio)->len = page_size; if (bio_ret) *bio_ret = bio; @@ -2914,7 +2950,7 @@ static int __do_readpage(struct extent_io_tree *tree, /* the get_extent function already copied into the page */ if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1, NULL)) { - check_page_uptodate(tree, page); + check_page_uptodate(tree, page, NULL); if (!parent_locked) unlock_extent(tree, cur, cur + iosize - 1); cur = cur + iosize; diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 80754f9..2e16f4d 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -174,6 +174,9 @@ struct btrfs_io_bio { u8 *csum_allocated; btrfs_io_bio_end_io_t *end_io; struct bio bio; + /* Track file offset range operated on by the bio.*/ + u64 start_offset; + u64 len; }; static inline struct btrfs_io_bio *btrfs_io_bio(struct bio *bio) -- 1.8.3.1