From 02f57c7aedef1a537f4b16db7061cdd8efa3bb4e Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 6 Apr 2011 14:25:44 -0400 Subject: [PATCH] Btrfs: don't split dio bios if we don't have to We have been unconditionally allocating a new bio and re-adding all pages from our original bio to the new bio. This is needed if our original bio is larger than our stripe size, but if it is smaller than the stripe size then there is no need to do this. So check the map length and if we are under that then go ahead and submit the original bio. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/inode.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 4a238d6..149c77f 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -6006,13 +6006,6 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, int ret = 0; int write = rw & REQ_WRITE; - bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS); - if (!bio) - return -ENOMEM; - bio->bi_private = dip; - bio->bi_end_io = btrfs_end_dio_bio; - atomic_inc(&dip->pending_bios); - map_length = orig_bio->bi_size; ret = btrfs_map_block(map_tree, READ, start_sector << 9, &map_length, NULL, 0); @@ -6021,6 +6014,18 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, return -EIO; } + if (map_length >= orig_bio->bi_size) { + bio = orig_bio; + goto submit; + } + + bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS); + if (!bio) + return -ENOMEM; + bio->bi_private = dip; + bio->bi_end_io = btrfs_end_dio_bio; + atomic_inc(&dip->pending_bios); + while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) { if (unlikely(map_length < submit_len + bvec->bv_len || bio_add_page(bio, bvec->bv_page, bvec->bv_len, @@ -6071,6 +6076,7 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, } } +submit: ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum, csums); if (!ret) -- 2.7.4