Btrfs: fix check_node and check_leaf to use less cpu

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 26 insertions, 18 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index dbd3f636dd3d..990d297a7a13 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -130,15 +130,17 @@ static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
                       int level)
 {
-        int i;
         struct btrfs_node *parent = NULL;
         struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
         int parent_slot;
+        int slot;
+        struct btrfs_key cpukey;
         u32 nritems = btrfs_header_nritems(&node->header);
 
         if (path->nodes[level + 1])
                 parent = btrfs_buffer_node(path->nodes[level + 1]);
         parent_slot = path->slots[level + 1];
+        slot = path->slots[level];
         BUG_ON(nritems == 0);
         if (parent) {
                 struct btrfs_disk_key *parent_key;
@@ -149,10 +151,13 @@ static int check_node(struct btrfs_root *root, struct btrfs_path *path,
                        btrfs_header_blocknr(&node->header));
         }
         BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
-        for (i = 0; nritems > 1 && i < nritems - 2; i++) {
-                struct btrfs_key cpukey;
-                btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[i + 1].key);
-                BUG_ON(comp_keys(&node->ptrs[i].key, &cpukey) >= 0);
+        if (slot != 0) {
+                btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[slot - 1].key);
+                BUG_ON(comp_keys(&node->ptrs[slot].key, &cpukey) <= 0);
+        }
+        if (slot < nritems - 1) {
+                btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[slot + 1].key);
+                BUG_ON(comp_keys(&node->ptrs[slot].key, &cpukey) >= 0);
         }
         return 0;
 }
@@ -160,10 +165,12 @@ static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
                       int level)
 {
-        int i;
         struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[level]);
         struct btrfs_node *parent = NULL;
         int parent_slot;
+        int slot = path->slots[0];
+        struct btrfs_key cpukey;
+
         u32 nritems = btrfs_header_nritems(&leaf->header);
 
         if (path->nodes[level + 1])
@@ -182,19 +189,20 @@ static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
                        btrfs_header_blocknr(&leaf->header));
         }
-        for (i = 0; nritems > 1 && i < nritems - 2; i++) {
-                struct btrfs_key cpukey;
-                btrfs_disk_key_to_cpu(&cpukey, &leaf->items[i + 1].key);
-                BUG_ON(comp_keys(&leaf->items[i].key,
-                                 &cpukey) >= 0);
-                BUG_ON(btrfs_item_offset(leaf->items + i) !=
-                        btrfs_item_end(leaf->items + i + 1));
-                if (i == 0) {
-                        BUG_ON(btrfs_item_offset(leaf->items + i) +
-                               btrfs_item_size(leaf->items + i) !=
-                               BTRFS_LEAF_DATA_SIZE(root));
-                }
+        if (slot != 0) {
+                btrfs_disk_key_to_cpu(&cpukey, &leaf->items[slot - 1].key);
+                BUG_ON(comp_keys(&leaf->items[slot].key, &cpukey) <= 0);
+                BUG_ON(btrfs_item_offset(leaf->items + slot - 1) !=
+                        btrfs_item_end(leaf->items + slot));
+        }
+        if (slot < nritems - 1) {
+                btrfs_disk_key_to_cpu(&cpukey, &leaf->items[slot + 1].key);
+                BUG_ON(comp_keys(&leaf->items[slot].key, &cpukey) >= 0);
+                BUG_ON(btrfs_item_offset(leaf->items + slot) !=
+                        btrfs_item_end(leaf->items + slot + 1));
         }
+        BUG_ON(btrfs_item_offset(leaf->items) +
+               btrfs_item_size(leaf->items) != BTRFS_LEAF_DATA_SIZE(root));
         return 0;
 }