From 3c12ac7205d4bd679fefa722aa9b61385e4b4749 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 21 Apr 2008 12:01:38 -0400 Subject: [PATCH] Btrfs: Simplify device selection for mirrored reads Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 8 ++++---- fs/btrfs/volumes.c | 23 +++++++---------------- 2 files changed, 11 insertions(+), 20 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 593011e..cc0d7f3 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -640,7 +640,7 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, if (!path) return -ENOMEM; - path->reada = 0; + path->reada = 1; key.objectid = bytenr; btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); key.offset = num_bytes; @@ -660,7 +660,7 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, btrfs_release_path(root->fs_info->extent_root, path); - path->reada = 0; + path->reada = 1; ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root, path, bytenr, root_objectid, ref_generation, owner, owner_offset); @@ -692,7 +692,7 @@ static int lookup_extent_ref(struct btrfs_trans_handle *trans, WARN_ON(num_bytes < root->sectorsize); path = btrfs_alloc_path(); - path->reada = 0; + path->reada = 1; key.objectid = bytenr; key.offset = num_bytes; btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); @@ -1328,7 +1328,7 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root if (!path) return -ENOMEM; - path->reada = 0; + path->reada = 1; ret = lookup_extent_backref(trans, extent_root, path, bytenr, root_objectid, ref_generation, diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 4602407..107fc74 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1029,19 +1029,8 @@ again: else if (mirror_num) { stripe_index = mirror_num - 1; } else { - int i; - u64 least = (u64)-1; - struct btrfs_device *cur; - - for (i = 0; i < map->num_stripes; i++) { - cur = map->stripes[i].dev; - spin_lock(&cur->io_lock); - if (cur->total_ios < least) { - least = cur->total_ios; - stripe_index = i; - } - spin_unlock(&cur->io_lock); - } + u64 orig_stripe_nr = stripe_nr; + stripe_index = do_div(orig_stripe_nr, num_stripes); } } else if (map->type & BTRFS_BLOCK_GROUP_DUP) { if (rw & (1 << BIO_RW)) @@ -1050,7 +1039,6 @@ again: stripe_index = mirror_num - 1; } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) { int factor = map->num_stripes / map->sub_stripes; - int orig_stripe_nr = stripe_nr; stripe_index = do_div(stripe_nr, factor); stripe_index *= map->sub_stripes; @@ -1059,8 +1047,11 @@ again: num_stripes = map->sub_stripes; else if (mirror_num) stripe_index += mirror_num - 1; - else - stripe_index += orig_stripe_nr % map->sub_stripes; + else { + u64 orig_stripe_nr = stripe_nr; + stripe_index += do_div(orig_stripe_nr, + map->sub_stripes); + } } else { /* * after this do_div call, stripe_nr is the number of stripes -- 2.7.4