From 9cd3a7eb8507deb3c75077739a07ccccad0dc991 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Thu, 3 Aug 2017 13:53:31 -0600 Subject: [PATCH] Btrfs: search parity device wisely After mapping block with BTRFS_MAP_WRITE, parities have been sorted to the end position, so this search can start from the first parity stripe. Signed-off-by: Liu Bo Reviewed-by: David Sterba [ copied changelog as a comment ] Signed-off-by: David Sterba --- fs/btrfs/raid56.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c index 24a62224b24b..cba5e7339462 100644 --- a/fs/btrfs/raid56.c +++ b/fs/btrfs/raid56.c @@ -2231,12 +2231,18 @@ raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio, ASSERT(!bio->bi_iter.bi_size); rbio->operation = BTRFS_RBIO_PARITY_SCRUB; - for (i = 0; i < rbio->real_stripes; i++) { + /* + * After mapping bbio with BTRFS_MAP_WRITE, parities have been sorted + * to the end position, so this search can start from the first parity + * stripe. + */ + for (i = rbio->nr_data; i < rbio->real_stripes; i++) { if (bbio->stripes[i].dev == scrub_dev) { rbio->scrubp = i; break; } } + ASSERT(i < rbio->real_stripes); /* Now we just support the sectorsize equals to page size */ ASSERT(fs_info->sectorsize == PAGE_SIZE); -- 2.30.2