Btrfs: Replace the big fs_mutex with a collection of other locks
[linux-2.6-block.git] / fs / btrfs / ctree.c
index 29e5674b043d09112b101a14f8ab26a06755bdec..dff4da082d06bcae80550d9f595033db20f4c1d4 100644 (file)
@@ -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);
@@ -62,12 +63,52 @@ void btrfs_free_path(struct btrfs_path *p)
 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
 {
        int i;
+       int skip = p->skip_locking;
+       int keep = p->keep_locks;
+
        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));
+       p->skip_locking = skip;
+       p->keep_locks = keep;
+}
+
+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)
@@ -111,7 +152,7 @@ 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 +192,14 @@ 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 +219,7 @@ 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 +243,14 @@ 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 +271,8 @@ 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;
@@ -302,6 +356,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
        struct extent_buffer *cur;
        struct extent_buffer *tmp;
        u64 blocknr;
+       u64 gen;
        u64 search_start = *last_ret;
        u64 last_block = 0;
        u64 other;
@@ -315,6 +370,9 @@ 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;
@@ -354,6 +412,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 
                progress_passed = 1;
                blocknr = btrfs_node_blockptr(parent, i);
+               gen = btrfs_node_ptr_generation(parent, i);
                if (last_block == 0)
                        last_block = blocknr;
 
@@ -361,7 +420,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                        other = btrfs_node_blockptr(parent, i - 1);
                        close = close_blocks(blocknr, other, blocksize);
                }
-               if (close && i < end_slot - 2) {
+               if (!close && i < end_slot - 2) {
                        other = btrfs_node_blockptr(parent, i + 1);
                        close = close_blocks(blocknr, other, blocksize);
                }
@@ -377,7 +436,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 
                cur = btrfs_find_tree_block(root, blocknr, blocksize);
                if (cur)
-                       uptodate = btrfs_buffer_uptodate(cur);
+                       uptodate = btrfs_buffer_uptodate(cur, gen);
                else
                        uptodate = 0;
                if (!cur || !uptodate) {
@@ -387,15 +446,14 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                        }
                        if (!cur) {
                                cur = read_tree_block(root, blocknr,
-                                                        blocksize);
+                                                        blocksize, gen);
                        } else if (!uptodate) {
-                               btrfs_read_buffer(cur);
+                               btrfs_read_buffer(cur, gen);
                        }
                }
                if (search_start == 0)
                        search_start = last_block;
 
-               btrfs_verify_block_csum(root, cur);
                err = __btrfs_cow_block(trans, root, cur, parent, i,
                                        &tmp, search_start,
                                        min(16 * blocksize,
@@ -696,12 +754,17 @@ static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
                                   struct extent_buffer *parent, int slot)
 {
+       int level = btrfs_header_level(parent);
        if (slot < 0)
                return NULL;
        if (slot >= btrfs_header_nritems(parent))
                return NULL;
+
+       BUG_ON(level == 0);
+
        return read_tree_block(root, btrfs_node_blockptr(parent, slot),
-                      btrfs_level_size(root, btrfs_header_level(parent) - 1));
+                      btrfs_level_size(root, level - 1),
+                      btrfs_node_ptr_generation(parent, slot));
 }
 
 static int balance_level(struct btrfs_trans_handle *trans,
@@ -723,6 +786,7 @@ 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);
@@ -743,14 +807,21 @@ 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,
@@ -769,6 +840,7 @@ 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) {
@@ -778,6 +850,7 @@ 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) {
@@ -809,6 +882,7 @@ 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 +
@@ -856,7 +930,9 @@ 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);
@@ -879,11 +955,14 @@ 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;
@@ -895,10 +974,15 @@ 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;
 }
 
@@ -936,6 +1020,8 @@ 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;
@@ -961,24 +1047,28 @@ 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;
@@ -1007,12 +1097,15 @@ 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;
@@ -1044,6 +1137,8 @@ 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);
@@ -1076,7 +1171,8 @@ static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
                if ((search >= lowest_read && search <= highest_read) ||
                    (search < lowest_read && lowest_read - search <= 32768) ||
                    (search > highest_read && search - highest_read <= 32768)) {
-                       readahead_tree_block(root, search, blocksize);
+                       readahead_tree_block(root, search, blocksize,
+                                    btrfs_node_ptr_generation(node, nr));
                        nread += blocksize;
                }
                nscan++;
@@ -1091,6 +1187,45 @@ 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 (nritems < 2 || path->slots[i] >= nritems - 2) {
+if (path->keep_locks) {
+//printk("path %p skip level now %d\n", path, skip_level);
+}
+                               skip_level = i + 1;
+                               continue;
+                       }
+               }
+               t = path->nodes[i];
+               if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
+if (path->keep_locks) {
+//printk("path %p unlocking level %d slot %d nritems %d skip_level %d\n", path, i, path->slots[i], btrfs_header_nritems(t), skip_level);
+}
+                       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
@@ -1109,21 +1244,30 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
                      ins_len, int cow)
 {
        struct extent_buffer *b;
-       u64 bytenr;
-       u64 ptr_gen;
        int slot;
        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(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) {
@@ -1142,9 +1286,12 @@ 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)
@@ -1172,22 +1319,19 @@ 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;
-                       bytenr = btrfs_node_blockptr(b, slot);
-                       ptr_gen = btrfs_node_ptr_generation(b, slot);
+                       }
+
                        if (should_reada)
                                reada_for_search(root, p, level, slot,
                                                 key->objectid);
-                       b = read_tree_block(root, bytenr,
-                                           btrfs_level_size(root, level - 1));
-                       if (ptr_gen != btrfs_header_generation(b)) {
-                               printk("block %llu bad gen wanted %llu "
-                                      "found %llu\n",
-                               (unsigned long long)b->start,
-                               (unsigned long long)ptr_gen,
-                               (unsigned long long)btrfs_header_generation(b));
-                       }
+
+                       b = read_node_slot(root, b, slot);
+                       if (!p->skip_locking)
+                               btrfs_tree_lock(b);
+                       unlock_up(p, level + 1, lowest_unlock);
                } else {
                        p->slots[level] = slot;
                        if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
@@ -1198,6 +1342,7 @@ again:
                                if (sret)
                                        return sret;
                        }
+                       unlock_up(p, level, lowest_unlock);
                        return ret;
                }
        }
@@ -1228,6 +1373,13 @@ 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;
@@ -1373,6 +1525,7 @@ 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]);
@@ -1389,12 +1542,13 @@ 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);
@@ -1419,23 +1573,31 @@ 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;
@@ -1524,7 +1686,7 @@ 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),
@@ -1567,10 +1729,12 @@ 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;
@@ -1650,32 +1814,27 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
        if (slot >= btrfs_header_nritems(upper) - 1)
                return 1;
 
-       right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
-                               root->leafsize);
+       WARN_ON(!btrfs_tree_locked(path->nodes[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;
@@ -1711,10 +1870,8 @@ 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);
@@ -1782,14 +1939,24 @@ 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
@@ -1826,12 +1993,14 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                return 1;
        }
 
-       left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
-                              slot - 1), root->leafsize);
+       WARN_ON(!btrfs_tree_locked(path->nodes[1]));
+
+       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 */
@@ -1839,14 +2008,14 @@ 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)
@@ -1881,8 +2050,8 @@ 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);
@@ -1980,15 +2149,23 @@ 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;
 }
 
 /*
@@ -2057,7 +2234,7 @@ 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);
@@ -2090,6 +2267,8 @@ 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;
@@ -2116,6 +2295,7 @@ 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;
@@ -2189,12 +2369,15 @@ 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);
 
@@ -2423,10 +2606,6 @@ 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) {
@@ -2521,7 +2700,6 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
                btrfs_print_leaf(root, leaf);
                BUG();
        }
-
 out:
        return ret;
 }
@@ -2660,7 +2838,6 @@ 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;
@@ -2711,8 +2888,6 @@ 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;
@@ -2725,7 +2900,13 @@ 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 {
@@ -2736,60 +2917,40 @@ 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)
 {
-       u64 bytenr;
-       int slot;
-       int level = 1;
-       struct extent_buffer *c;
-       struct extent_buffer *next = NULL;
-
-       while(level < BTRFS_MAX_LEVEL) {
-               if (!path->nodes[level])
-                       return 1;
+       struct btrfs_key key;
+       struct btrfs_disk_key found_key;
+       int ret;
 
-               slot = path->slots[level];
-               c = path->nodes[level];
-               if (slot == 0) {
-                       level++;
-                       if (level == BTRFS_MAX_LEVEL)
-                               return 1;
-                       continue;
-               }
-               slot--;
+       btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
 
-               bytenr = btrfs_node_blockptr(c, 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_tree_block(root, bytenr,
-                                      btrfs_level_size(root, level - 1));
-               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_tree_block(root, btrfs_node_blockptr(next, slot),
-                                      btrfs_level_size(root, level - 1));
-       }
-       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.
  */
@@ -2797,9 +2958,31 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
 {
        int slot;
        int level = 1;
-       u64 bytenr;
        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);
+
+       btrfs_release_path(root, path);
+       path->keep_locks = 1;
+       ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+       path->keep_locks = 0;
+
+       if (ret < 0)
+               return ret;
+
+       nritems = btrfs_header_nritems(path->nodes[0]);
+       if (nritems > 0 && path->slots[0] < nritems - 1) {
+               goto done;
+       }
 
        while(level < BTRFS_MAX_LEVEL) {
                if (!path->nodes[level])
@@ -2809,36 +2992,56 @@ 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;
                }
 
-               bytenr = btrfs_node_blockptr(c, slot);
-               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_tree_block(root, bytenr,
-                                      btrfs_level_size(root, level -1));
+               next = read_node_slot(root, c, slot);
+               if (!path->skip_locking) {
+                       if (!btrfs_tree_locked(c)) {
+                               int i;
+                               WARN_ON(1);
+printk("path %p no lock on level %d\n", path, level);
+for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
+printk("path %p level %d slot %d nritems %d\n", path, i, path->slots[i], btrfs_header_nritems(path->nodes[i]));
+}
+                       }
+                       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);
-               next = read_tree_block(root, btrfs_node_blockptr(next, 0),
-                                      btrfs_level_size(root, level - 1));
+               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) {
+                       WARN_ON(!btrfs_tree_locked(path->nodes[level]));
+                       btrfs_tree_lock(next);
+               }
        }
+done:
+       unlock_up(path, 0, 1);
        return 0;
 }