1 files changed, 288 insertions, 98 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 1d404bde3cfa..75625c68fdd8 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -21,6 +21,7 @@
 #include "disk-io.h"
 #include "transaction.h"
 #include "print-tree.h"
+#include "locking.h"
 
 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root, struct btrfs_path *path, int level);
@@ -64,12 +65,47 @@ void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
         int i;
         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
                 if (!p->nodes[i])
-                        break;
+                        continue;
+                if (p->locks[i]) {
+                        btrfs_tree_unlock(p->nodes[i]);
+                        p->locks[i] = 0;
+                }
                 free_extent_buffer(p->nodes[i]);
         }
         memset(p, 0, sizeof(*p));
 }
 
+struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
+{
+        struct extent_buffer *eb;
+        spin_lock(&root->node_lock);
+        eb = root->node;
+        extent_buffer_get(eb);
+        spin_unlock(&root->node_lock);
+        return eb;
+}
+
+struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
+{
+        struct extent_buffer *eb;
+
+        while(1) {
+                eb = btrfs_root_node(root);
+                btrfs_tree_lock(eb);
+
+                spin_lock(&root->node_lock);
+                if (eb == root->node) {
+                        spin_unlock(&root->node_lock);
+                        break;
+                }
+                spin_unlock(&root->node_lock);
+
+                btrfs_tree_unlock(eb);
+                free_extent_buffer(eb);
+        }
+        return eb;
+}
+
 static void add_root_to_dirty_list(struct btrfs_root *root)
 {
         if (root->track_dirty && list_empty(&root->dirty_list)) {
@@ -111,7 +147,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
         } else {
                 first_key.objectid = 0;
         }
-        cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
+        cow = btrfs_alloc_free_block(trans, new_root, buf->len,
                                        new_root_objectid,
                                        trans->transid, first_key.objectid,
                                        level, buf->start, 0);
@@ -151,8 +187,14 @@ int __btrfs_cow_block(struct btrfs_trans_handle *trans,
         int ret = 0;
         int different_trans = 0;
         int level;
+        int unlock_orig = 0;
         struct btrfs_key first_key;
 
+        if (*cow_ret == buf)
+                unlock_orig = 1;
+
+        WARN_ON(!btrfs_tree_locked(buf));
+
         if (root->ref_cows) {
                 root_gen = trans->transid;
         } else {
@@ -172,7 +214,7 @@ int __btrfs_cow_block(struct btrfs_trans_handle *trans,
         } else {
                 first_key.objectid = 0;
         }
-        cow = __btrfs_alloc_free_block(trans, root, buf->len,
+        cow = btrfs_alloc_free_block(trans, root, buf->len,
                                      root->root_key.objectid,
                                      root_gen, first_key.objectid, level,
                                      search_start, empty_size);
@@ -196,9 +238,14 @@ int __btrfs_cow_block(struct btrfs_trans_handle *trans,
         }
 
         if (buf == root->node) {
+                WARN_ON(parent && parent != buf);
                 root_gen = btrfs_header_generation(buf);
+
+                spin_lock(&root->node_lock);
                 root->node = cow;
                 extent_buffer_get(cow);
+                spin_unlock(&root->node_lock);
+
                 if (buf != root->commit_root) {
                         btrfs_free_extent(trans, root, buf->start,
                                           buf->len, root->root_key.objectid,
@@ -219,6 +266,8 @@ int __btrfs_cow_block(struct btrfs_trans_handle *trans,
                                   btrfs_header_owner(parent), root_gen,
                                   0, 0, 1);
         }
+        if (unlock_orig)
+                btrfs_tree_unlock(buf);
         free_extent_buffer(buf);
         btrfs_mark_buffer_dirty(cow);
         *cow_ret = cow;
@@ -316,6 +365,9 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
         int progress_passed = 0;
         struct btrfs_disk_key disk_key;
 
+        /* FIXME this code needs locking */
+        return 0;
+
         parent_level = btrfs_header_level(parent);
         if (cache_only && parent_level != 1)
                 return 0;
@@ -729,6 +781,7 @@ static int balance_level(struct btrfs_trans_handle *trans,
                 return 0;
 
         mid = path->nodes[level];
+        WARN_ON(!path->locks[level]);
         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 
         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
@@ -749,14 +802,21 @@ static int balance_level(struct btrfs_trans_handle *trans,
 
                 /* promote the child to a root */
                 child = read_node_slot(root, mid, 0);
+                btrfs_tree_lock(child);
                 BUG_ON(!child);
                 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
                 BUG_ON(ret);
 
+                spin_lock(&root->node_lock);
                 root->node = child;
+                spin_unlock(&root->node_lock);
+
                 add_root_to_dirty_list(root);
+                btrfs_tree_unlock(child);
+                path->locks[level] = 0;
                 path->nodes[level] = NULL;
                 clean_tree_block(trans, root, mid);
+                btrfs_tree_unlock(mid);
                 /* once for the path */
                 free_extent_buffer(mid);
                 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
@@ -775,6 +835,7 @@ static int balance_level(struct btrfs_trans_handle *trans,
 
         left = read_node_slot(root, parent, pslot - 1);
         if (left) {
+                btrfs_tree_lock(left);
                 wret = btrfs_cow_block(trans, root, left,
                                        parent, pslot - 1, &left);
                 if (wret) {
@@ -784,6 +845,7 @@ static int balance_level(struct btrfs_trans_handle *trans,
         }
         right = read_node_slot(root, parent, pslot + 1);
         if (right) {
+                btrfs_tree_lock(right);
                 wret = btrfs_cow_block(trans, root, right,
                                        parent, pslot + 1, &right);
                 if (wret) {
@@ -815,6 +877,7 @@ static int balance_level(struct btrfs_trans_handle *trans,
                         u32 blocksize = right->len;
 
                         clean_tree_block(trans, root, right);
+                        btrfs_tree_unlock(right);
                         free_extent_buffer(right);
                         right = NULL;
                         wret = del_ptr(trans, root, path, level + 1, pslot +
@@ -862,7 +925,9 @@ static int balance_level(struct btrfs_trans_handle *trans,
                 u64 root_gen = btrfs_header_generation(parent);
                 u64 bytenr = mid->start;
                 u32 blocksize = mid->len;
+
                 clean_tree_block(trans, root, mid);
+                btrfs_tree_unlock(mid);
                 free_extent_buffer(mid);
                 mid = NULL;
                 wret = del_ptr(trans, root, path, level + 1, pslot);
@@ -885,11 +950,14 @@ static int balance_level(struct btrfs_trans_handle *trans,
         if (left) {
                 if (btrfs_header_nritems(left) > orig_slot) {
                         extent_buffer_get(left);
+                        /* left was locked after cow */
                         path->nodes[level] = left;
                         path->slots[level + 1] -= 1;
                         path->slots[level] = orig_slot;
-                        if (mid)
+                        if (mid) {
+                                btrfs_tree_unlock(mid);
                                 free_extent_buffer(mid);
+                        }
                 } else {
                         orig_slot -= btrfs_header_nritems(left);
                         path->slots[level] = orig_slot;
@@ -901,10 +969,15 @@ static int balance_level(struct btrfs_trans_handle *trans,
             btrfs_node_blockptr(path->nodes[level], path->slots[level]))
                 BUG();
 enospc:
-        if (right)
+        if (right) {
+                btrfs_tree_unlock(right);
                 free_extent_buffer(right);
-        if (left)
+        }
+        if (left) {
+                if (path->nodes[level] != left)
+                        btrfs_tree_unlock(left);
                 free_extent_buffer(left);
+        }
         return ret;
 }
 
@@ -942,6 +1015,8 @@ static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
         /* first, try to make some room in the middle buffer */
         if (left) {
                 u32 left_nr;
+
+                btrfs_tree_lock(left);
                 left_nr = btrfs_header_nritems(left);
                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
                         wret = 1;
@@ -967,24 +1042,28 @@ static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
                                 path->nodes[level] = left;
                                 path->slots[level + 1] -= 1;
                                 path->slots[level] = orig_slot;
+                                btrfs_tree_unlock(mid);
                                 free_extent_buffer(mid);
                         } else {
                                 orig_slot -=
                                         btrfs_header_nritems(left);
                                 path->slots[level] = orig_slot;
+                                btrfs_tree_unlock(left);
                                 free_extent_buffer(left);
                         }
                         return 0;
                 }
+                btrfs_tree_unlock(left);
                 free_extent_buffer(left);
         }
-        right= read_node_slot(root, parent, pslot + 1);
+        right = read_node_slot(root, parent, pslot + 1);
 
         /*
          * then try to empty the right most buffer into the middle
          */
         if (right) {
                 u32 right_nr;
+                btrfs_tree_lock(right);
                 right_nr = btrfs_header_nritems(right);
                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
                         wret = 1;
@@ -1013,12 +1092,15 @@ static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
                                 path->slots[level + 1] += 1;
                                 path->slots[level] = orig_slot -
                                         btrfs_header_nritems(mid);
+                                btrfs_tree_unlock(mid);
                                 free_extent_buffer(mid);
                         } else {
+                                btrfs_tree_unlock(right);
                                 free_extent_buffer(right);
                         }
                         return 0;
                 }
+                btrfs_tree_unlock(right);
                 free_extent_buffer(right);
         }
         return 1;
@@ -1050,6 +1132,8 @@ static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
                 return;
 
         node = path->nodes[level];
+        WARN_ON(!path->skip_locking && !btrfs_tree_locked(node));
+
         search = btrfs_node_blockptr(node, slot);
         blocksize = btrfs_level_size(root, level - 1);
         eb = btrfs_find_tree_block(root, search, blocksize);
@@ -1098,6 +1182,39 @@ static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
                         highest_read = search;
         }
 }
+
+static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
+{
+        int i;
+        int skip_level = level;
+        struct extent_buffer *t;
+
+        for (i = level; i < BTRFS_MAX_LEVEL; i++) {
+                if (!path->nodes[i])
+                        break;
+                if (!path->locks[i])
+                        break;
+                if (path->slots[i] == 0) {
+                        skip_level = i + 1;
+                        continue;
+                }
+                if (path->keep_locks) {
+                        u32 nritems;
+                        t = path->nodes[i];
+                        nritems = btrfs_header_nritems(t);
+                        if (path->slots[i] >= nritems - 1) {
+                                skip_level = i + 1;
+                                continue;
+                        }
+                }
+                t = path->nodes[i];
+                if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
+                        btrfs_tree_unlock(t);
+                        path->locks[i] = 0;
+                }
+        }
+}
+
 /*
  * look for key in the tree.  path is filled in with nodes along the way
  * if key is found, we return zero and you can find the item in the leaf
@@ -1120,15 +1237,27 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
         int ret;
         int level;
         int should_reada = p->reada;
+        int lowest_unlock = 1;
         u8 lowest_level = 0;
 
         lowest_level = p->lowest_level;
         WARN_ON(lowest_level && ins_len);
         WARN_ON(p->nodes[0] != NULL);
-        WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
+        // WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
+        WARN_ON(root == root->fs_info->extent_root &&
+                !mutex_is_locked(&root->fs_info->alloc_mutex));
+        WARN_ON(root == root->fs_info->chunk_root &&
+                !mutex_is_locked(&root->fs_info->chunk_mutex));
+        WARN_ON(root == root->fs_info->dev_root &&
+                !mutex_is_locked(&root->fs_info->chunk_mutex));
+        if (ins_len < 0)
+                lowest_unlock = 2;
 again:
-        b = root->node;
-        extent_buffer_get(b);
+        if (!p->skip_locking)
+                b = btrfs_lock_root_node(root);
+        else
+                b = btrfs_root_node(root);
+
         while (b) {
                 level = btrfs_header_level(b);
                 if (cow) {
@@ -1147,9 +1276,12 @@ again:
                         WARN_ON(1);
                 level = btrfs_header_level(b);
                 p->nodes[level] = b;
+                if (!p->skip_locking)
+                        p->locks[level] = 1;
                 ret = check_block(root, p, level);
                 if (ret)
                         return -1;
+
                 ret = bin_search(b, key, level, &slot);
                 if (level != 0) {
                         if (ret && slot > 0)
@@ -1177,14 +1309,19 @@ again:
                                 BUG_ON(btrfs_header_nritems(b) == 1);
                         }
                         /* this is only true while dropping a snapshot */
-                        if (level == lowest_level)
+                        if (level == lowest_level) {
+                                unlock_up(p, level, lowest_unlock);
                                 break;
+                        }
 
                         if (should_reada)
                                 reada_for_search(root, p, level, slot,
                                                  key->objectid);
 
                         b = read_node_slot(root, b, slot);
+                        if (!p->skip_locking)
+                                btrfs_tree_lock(b);
+                        unlock_up(p, level, lowest_unlock);
                 } else {
                         p->slots[level] = slot;
                         if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
@@ -1195,6 +1332,7 @@ again:
                                 if (sret)
                                         return sret;
                         }
+                        unlock_up(p, level, lowest_unlock);
                         return ret;
                 }
         }
@@ -1225,6 +1363,13 @@ static int fixup_low_keys(struct btrfs_trans_handle *trans,
                         break;
                 t = path->nodes[i];
                 btrfs_set_node_key(t, key, tslot);
+                if (!btrfs_tree_locked(path->nodes[i])) {
+                        int ii;
+printk("fixup without lock on level %d\n", btrfs_header_level(path->nodes[i]));
+                        for (ii = 0; ii < BTRFS_MAX_LEVEL; ii++) {
+printk("level %d slot %d\n", ii, path->slots[ii]);
+                        }
+                }
                 btrfs_mark_buffer_dirty(path->nodes[i]);
                 if (tslot != 0)
                         break;
@@ -1370,6 +1515,7 @@ static int noinline insert_new_root(struct btrfs_trans_handle *trans,
         u64 lower_gen;
         struct extent_buffer *lower;
         struct extent_buffer *c;
+        struct extent_buffer *old;
         struct btrfs_disk_key lower_key;
 
         BUG_ON(path->nodes[level]);
@@ -1386,12 +1532,13 @@ static int noinline insert_new_root(struct btrfs_trans_handle *trans,
         else
                 btrfs_node_key(lower, &lower_key, 0);
 
-        c = __btrfs_alloc_free_block(trans, root, root->nodesize,
+        c = btrfs_alloc_free_block(trans, root, root->nodesize,
                                    root->root_key.objectid,
                                    root_gen, lower_key.objectid, level,
                                    root->node->start, 0);
         if (IS_ERR(c))
                 return PTR_ERR(c);
+
         memset_extent_buffer(c, 0, 0, root->nodesize);
         btrfs_set_header_nritems(c, 1);
         btrfs_set_header_level(c, level);
@@ -1416,23 +1563,31 @@ static int noinline insert_new_root(struct btrfs_trans_handle *trans,
 
         btrfs_mark_buffer_dirty(c);
 
-        /* the super has an extra ref to root->node */
-        free_extent_buffer(root->node);
+        spin_lock(&root->node_lock);
+        old = root->node;
         root->node = c;
+        spin_unlock(&root->node_lock);
+
+        /* the super has an extra ref to root->node */
+        free_extent_buffer(old);
+
         add_root_to_dirty_list(root);
         extent_buffer_get(c);
         path->nodes[level] = c;
+        path->locks[level] = 1;
         path->slots[level] = 0;
 
         if (root->ref_cows && lower_gen != trans->transid) {
                 struct btrfs_path *back_path = btrfs_alloc_path();
                 int ret;
+                mutex_lock(&root->fs_info->alloc_mutex);
                 ret = btrfs_insert_extent_backref(trans,
                                                   root->fs_info->extent_root,
                                                   path, lower->start,
                                                   root->root_key.objectid,
                                                   trans->transid, 0, 0);
                 BUG_ON(ret);
+                mutex_unlock(&root->fs_info->alloc_mutex);
                 btrfs_free_path(back_path);
         }
         return 0;
@@ -1521,7 +1676,7 @@ static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
                 root_gen = 0;
 
         btrfs_node_key(c, &disk_key, 0);
-        split = __btrfs_alloc_free_block(trans, root, root->nodesize,
+        split = btrfs_alloc_free_block(trans, root, root->nodesize,
                                          root->root_key.objectid,
                                          root_gen,
                                          btrfs_disk_key_objectid(&disk_key),
@@ -1564,10 +1719,12 @@ static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
 
         if (path->slots[level] >= mid) {
                 path->slots[level] -= mid;
+                btrfs_tree_unlock(c);
                 free_extent_buffer(c);
                 path->nodes[level] = split;
                 path->slots[level + 1] += 1;
         } else {
+                btrfs_tree_unlock(split);
                 free_extent_buffer(split);
         }
         return ret;
@@ -1648,30 +1805,24 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
                 return 1;
 
         right = read_node_slot(root, upper, slot + 1);
+        btrfs_tree_lock(right);
         free_space = btrfs_leaf_free_space(root, right);
-        if (free_space < data_size + sizeof(struct btrfs_item)) {
-                free_extent_buffer(right);
-                return 1;
-        }
+        if (free_space < data_size + sizeof(struct btrfs_item))
+                goto out_unlock;
 
         /* cow and double check */
         ret = btrfs_cow_block(trans, root, right, upper,
                               slot + 1, &right);
-        if (ret) {
-                free_extent_buffer(right);
-                return 1;
-        }
+        if (ret)
+                goto out_unlock;
+
         free_space = btrfs_leaf_free_space(root, right);
-        if (free_space < data_size + sizeof(struct btrfs_item)) {
-                free_extent_buffer(right);
-                return 1;
-        }
+        if (free_space < data_size + sizeof(struct btrfs_item))
+                goto out_unlock;
 
         left_nritems = btrfs_header_nritems(left);
-        if (left_nritems == 0) {
-                free_extent_buffer(right);
-                return 1;
-        }
+        if (left_nritems == 0)
+                goto out_unlock;
 
         if (empty)
                 nr = 0;
@@ -1707,10 +1858,8 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
                 left->map_token = NULL;
         }
 
-        if (push_items == 0) {
-                free_extent_buffer(right);
-                return 1;
-        }
+        if (push_items == 0)
+                goto out_unlock;
 
         if (!empty && push_items == left_nritems)
                 WARN_ON(1);
@@ -1778,14 +1927,24 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
         /* then fixup the leaf pointer in the path */
         if (path->slots[0] >= left_nritems) {
                 path->slots[0] -= left_nritems;
+                if (btrfs_header_nritems(path->nodes[0]) == 0)
+                        clean_tree_block(trans, root, path->nodes[0]);
+                btrfs_tree_unlock(path->nodes[0]);
                 free_extent_buffer(path->nodes[0]);
                 path->nodes[0] = right;
                 path->slots[1] += 1;
         } else {
+                btrfs_tree_unlock(right);
                 free_extent_buffer(right);
         }
         return 0;
+
+out_unlock:
+        btrfs_tree_unlock(right);
+        free_extent_buffer(right);
+        return 1;
 }
+
 /*
  * push some data in the path leaf to the left, trying to free up at
  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
@@ -1823,10 +1982,11 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
         }
 
         left = read_node_slot(root, path->nodes[1], slot - 1);
+        btrfs_tree_lock(left);
         free_space = btrfs_leaf_free_space(root, left);
         if (free_space < data_size + sizeof(struct btrfs_item)) {
-                free_extent_buffer(left);
-                return 1;
+                ret = 1;
+                goto out;
         }
 
         /* cow and double check */
@@ -1834,14 +1994,14 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                               path->nodes[1], slot - 1, &left);
         if (ret) {
                 /* we hit -ENOSPC, but it isn't fatal here */
-                free_extent_buffer(left);
-                return 1;
+                ret = 1;
+                goto out;
         }
 
         free_space = btrfs_leaf_free_space(root, left);
         if (free_space < data_size + sizeof(struct btrfs_item)) {
-                free_extent_buffer(left);
-                return 1;
+                ret = 1;
+                goto out;
         }
 
         if (empty)
@@ -1876,8 +2036,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
         }
 
         if (push_items == 0) {
-                free_extent_buffer(left);
-                return 1;
+                ret = 1;
+                goto out;
         }
         if (!empty && push_items == btrfs_header_nritems(right))
                 WARN_ON(1);
@@ -1975,15 +2135,23 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
         /* then fixup the leaf pointer in the path */
         if (path->slots[0] < push_items) {
                 path->slots[0] += old_left_nritems;
+                if (btrfs_header_nritems(path->nodes[0]) == 0)
+                        clean_tree_block(trans, root, path->nodes[0]);
+                btrfs_tree_unlock(path->nodes[0]);
                 free_extent_buffer(path->nodes[0]);
                 path->nodes[0] = left;
                 path->slots[1] -= 1;
         } else {
+                btrfs_tree_unlock(left);
                 free_extent_buffer(left);
                 path->slots[0] -= push_items;
         }
         BUG_ON(path->slots[0] < 0);
         return ret;
+out:
+        btrfs_tree_unlock(left);
+        free_extent_buffer(left);
+        return ret;
 }
 
 /*
@@ -2052,7 +2220,7 @@ again:
 
         btrfs_item_key(l, &disk_key, 0);
 
-        right = __btrfs_alloc_free_block(trans, root, root->leafsize,
+        right = btrfs_alloc_free_block(trans, root, root->leafsize,
                                          root->root_key.objectid,
                                          root_gen, disk_key.objectid, 0,
                                          l->start, 0);
@@ -2085,6 +2253,8 @@ again:
                                                   path->slots[1] + 1, 1);
                                 if (wret)
                                         ret = wret;
+
+                                btrfs_tree_unlock(path->nodes[0]);
                                 free_extent_buffer(path->nodes[0]);
                                 path->nodes[0] = right;
                                 path->slots[0] = 0;
@@ -2111,6 +2281,7 @@ again:
                                                   path->slots[1], 1);
                                 if (wret)
                                         ret = wret;
+                                btrfs_tree_unlock(path->nodes[0]);
                                 free_extent_buffer(path->nodes[0]);
                                 path->nodes[0] = right;
                                 path->slots[0] = 0;
@@ -2184,12 +2355,15 @@ again:
         BUG_ON(path->slots[0] != slot);
 
         if (mid <= slot) {
+                btrfs_tree_unlock(path->nodes[0]);
                 free_extent_buffer(path->nodes[0]);
                 path->nodes[0] = right;
                 path->slots[0] -= mid;
                 path->slots[1] += 1;
-        } else
+        } else {
+                btrfs_tree_unlock(right);
                 free_extent_buffer(right);
+        }
 
         BUG_ON(path->slots[0] < 0);
 
@@ -2418,10 +2592,6 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
                 total_data += data_size[i];
         }
 
-        /* create a root if there isn't one */
-        if (!root->node)
-                BUG();
-
         total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
         if (ret == 0) {
@@ -2516,7 +2686,6 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
                 btrfs_print_leaf(root, leaf);
                 BUG();
         }
-
 out:
         return ret;
 }
@@ -2655,7 +2824,6 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                         btrfs_set_header_level(leaf, 0);
                 } else {
                         u64 root_gen = btrfs_header_generation(path->nodes[1]);
-                        clean_tree_block(trans, root, leaf);
                         wret = del_ptr(trans, root, path, 1, path->slots[1]);
                         if (wret)
                                 ret = wret;
@@ -2706,8 +2874,6 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                                 root_gen = btrfs_header_generation(
                                                            path->nodes[1]);
 
-                                clean_tree_block(trans, root, leaf);
-
                                 wret = del_ptr(trans, root, path, 1, slot);
                                 if (wret)
                                         ret = wret;
@@ -2720,7 +2886,13 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                                 if (wret)
                                         ret = wret;
                         } else {
-                                btrfs_mark_buffer_dirty(leaf);
+                                /* if we're still in the path, make sure
+                                 * we're dirty.  Otherwise, one of the
+                                 * push_leaf functions must have already
+                                 * dirtied this buffer
+                                 */
+                                if (path->nodes[0] == leaf)
+                                        btrfs_mark_buffer_dirty(leaf);
                                 free_extent_buffer(leaf);
                         }
                 } else {
@@ -2731,56 +2903,40 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 }
 
 /*
- * walk up the tree as far as required to find the previous leaf.
+ * search the tree again to find a leaf with lesser keys
  * returns 0 if it found something or 1 if there are no lesser leaves.
  * returns < 0 on io errors.
  */
 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
 {
-        int slot;
-        int level = 1;
-        struct extent_buffer *c;
-        struct extent_buffer *next = NULL;
+        struct btrfs_key key;
+        struct btrfs_disk_key found_key;
+        int ret;
 
-        while(level < BTRFS_MAX_LEVEL) {
-                if (!path->nodes[level])
-                        return 1;
+        btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
 
-                slot = path->slots[level];
-                c = path->nodes[level];
-                if (slot == 0) {
-                        level++;
-                        if (level == BTRFS_MAX_LEVEL)
-                                return 1;
-                        continue;
-                }
-                slot--;
-
-                if (next)
-                        free_extent_buffer(next);
+        if (key.offset > 0)
+                key.offset--;
+        else if (key.type > 0)
+                key.type--;
+        else if (key.objectid > 0)
+                key.objectid--;
+        else
+                return 1;
 
-                next = read_node_slot(root, c, slot);
-                break;
-        }
-        path->slots[level] = slot;
-        while(1) {
-                level--;
-                c = path->nodes[level];
-                free_extent_buffer(c);
-                slot = btrfs_header_nritems(next);
-                if (slot != 0)
-                        slot--;
-                path->nodes[level] = next;
-                path->slots[level] = slot;
-                if (!level)
-                        break;
-                next = read_node_slot(root, next, slot);
-        }
-        return 0;
+        btrfs_release_path(root, path);
+        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+        if (ret < 0)
+                return ret;
+        btrfs_item_key(path->nodes[0], &found_key, 0);
+        ret = comp_keys(&found_key, &key);
+        if (ret < 0)
+                return 0;
+        return 1;
 }
 
 /*
- * walk up the tree as far as required to find the next leaf.
+ * search the tree again to find a leaf with greater keys
  * returns 0 if it found something or 1 if there are no greater leaves.
  * returns < 0 on io errors.
  */
@@ -2790,6 +2946,28 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
         int level = 1;
         struct extent_buffer *c;
         struct extent_buffer *next = NULL;
+        struct btrfs_key key;
+        u32 nritems;
+        int ret;
+
+        nritems = btrfs_header_nritems(path->nodes[0]);
+        if (nritems == 0) {
+                return 1;
+        }
+
+        btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
+
+        path->keep_locks = 1;
+        btrfs_release_path(root, path);
+        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+        path->keep_locks = 0;
+
+        if (ret < 0)
+                return ret;
+
+        if (path->slots[0] < nritems - 1) {
+                goto done;
+        }
 
         while(level < BTRFS_MAX_LEVEL) {
                 if (!path->nodes[level])
@@ -2799,33 +2977,45 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
                 c = path->nodes[level];
                 if (slot >= btrfs_header_nritems(c)) {
                         level++;
-                        if (level == BTRFS_MAX_LEVEL)
+                        if (level == BTRFS_MAX_LEVEL) {
                                 return 1;
+                        }
                         continue;
                 }
 
-                if (next)
+                if (next) {
+                        btrfs_tree_unlock(next);
                         free_extent_buffer(next);
+                }
 
-                if (path->reada)
+                if (level == 1 && path->locks[1] && path->reada)
                         reada_for_search(root, path, level, slot, 0);
 
                 next = read_node_slot(root, c, slot);
+                if (!path->skip_locking)
+                        btrfs_tree_lock(next);
                 break;
         }
         path->slots[level] = slot;
         while(1) {
                 level--;
                 c = path->nodes[level];
+                if (path->locks[level])
+                        btrfs_tree_unlock(c);
                 free_extent_buffer(c);
                 path->nodes[level] = next;
                 path->slots[level] = 0;
+                path->locks[level] = 1;
                 if (!level)
                         break;
-                if (path->reada)
-                        reada_for_search(root, path, level, 0, 0);
+                if (level == 1 && path->locks[1] && path->reada)
+                        reada_for_search(root, path, level, slot, 0);
                 next = read_node_slot(root, next, 0);
+                if (!path->skip_locking)
+                        btrfs_tree_lock(next);
         }
+done:
+        unlock_up(path, 0, 1);
         return 0;
 }