Btrfs: dynamic allocation of path struct

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

6 files changed, 243 insertions, 172 deletions

diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index f55c89472ac0..baceb1da609f 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -9,7 +9,7 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
                           objectid, u8 type)
 {
         int ret = 0;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_dir_item *dir_item;
         char *name_ptr;
         struct btrfs_key key;
@@ -20,24 +20,26 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
         ret = btrfs_name_hash(name, name_len, &key.offset);
         BUG_ON(ret);
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        btrfs_init_path(path);
         data_size = sizeof(*dir_item) + name_len;
-        ret = btrfs_insert_empty_item(trans, root, &path, &key, data_size);
+        ret = btrfs_insert_empty_item(trans, root, path, &key, data_size);
         if (ret)
                 goto out;
 
-        dir_item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
-                                  path.slots[0],
+        dir_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
+                                  path->slots[0],
                                   struct btrfs_dir_item);
         btrfs_set_dir_objectid(dir_item, objectid);
         btrfs_set_dir_type(dir_item, type);
         btrfs_set_dir_flags(dir_item, 0);
         btrfs_set_dir_name_len(dir_item, name_len);
         name_ptr = (char *)(dir_item + 1);
-        btrfs_memcpy(root, path.nodes[0]->b_data, name_ptr, name, name_len);
-        btrfs_mark_buffer_dirty(path.nodes[0]);
+        btrfs_memcpy(root, path->nodes[0]->b_data, name_ptr, name, name_len);
+        btrfs_mark_buffer_dirty(path->nodes[0]);
 out:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 37b87e28a2f3..d785b721b461 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -15,7 +15,7 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
 static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
                          *root, u64 blocknr, u64 num_blocks)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         int ret;
         struct btrfs_key key;
         struct btrfs_leaf *l;
@@ -25,23 +25,26 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
 
         find_free_extent(trans, root->fs_info->extent_root, 0, 0, (u64)-1,
                          &ins);
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
         key.objectid = blocknr;
         key.flags = 0;
         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
         key.offset = num_blocks;
-        ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
+        ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
                                 0, 1);
         if (ret != 0)
                 BUG();
         BUG_ON(ret != 0);
-        l = btrfs_buffer_leaf(path.nodes[0]);
-        item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item);
+        l = btrfs_buffer_leaf(path->nodes[0]);
+        item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
         refs = btrfs_extent_refs(item);
         btrfs_set_extent_refs(item, refs + 1);
-        btrfs_mark_buffer_dirty(path.nodes[0]);
+        btrfs_mark_buffer_dirty(path->nodes[0]);
 
-        btrfs_release_path(root->fs_info->extent_root, &path);
+        btrfs_release_path(root->fs_info->extent_root, path);
+        btrfs_free_path(path);
         finish_current_insert(trans, root->fs_info->extent_root);
         del_pending_extents(trans, root->fs_info->extent_root);
         return 0;
@@ -50,24 +53,27 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
 static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
                             *root, u64 blocknr, u64 num_blocks, u32 *refs)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         int ret;
         struct btrfs_key key;
         struct btrfs_leaf *l;
         struct btrfs_extent_item *item;
-        btrfs_init_path(&path);
+
+        path = btrfs_alloc_path();
+        btrfs_init_path(path);
         key.objectid = blocknr;
         key.offset = num_blocks;
         key.flags = 0;
         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
-        ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
+        ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
                                 0, 0);
         if (ret != 0)
                 BUG();
-        l = btrfs_buffer_leaf(path.nodes[0]);
-        item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item);
+        l = btrfs_buffer_leaf(path->nodes[0]);
+        item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
         *refs = btrfs_extent_refs(item);
-        btrfs_release_path(root->fs_info->extent_root, &path);
+        btrfs_release_path(root->fs_info->extent_root, path);
+        btrfs_free_path(path);
         return 0;
 }
 
@@ -200,7 +206,7 @@ static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                          *root, u64 blocknr, u64 num_blocks, int pin)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_key key;
         struct btrfs_fs_info *info = root->fs_info;
         struct btrfs_root *extent_root = info->extent_root;
@@ -215,20 +221,22 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
         key.offset = num_blocks;
 
         find_free_extent(trans, root, 0, 0, (u64)-1, &ins);
-        btrfs_init_path(&path);
-        ret = btrfs_search_slot(trans, extent_root, &key, &path, -1, 1);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
+        ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
         if (ret) {
                 printk("failed to find %Lu\n", key.objectid);
                 btrfs_print_tree(extent_root, extent_root->node);
                 printk("failed to find %Lu\n", key.objectid);
                 BUG();
         }
-        ei = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+        ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                             struct btrfs_extent_item);
         BUG_ON(ei->refs == 0);
         refs = btrfs_extent_refs(ei) - 1;
         btrfs_set_extent_refs(ei, refs);
-        btrfs_mark_buffer_dirty(path.nodes[0]);
+        btrfs_mark_buffer_dirty(path->nodes[0]);
         if (refs == 0) {
                 u64 super_blocks_used;
 
@@ -240,13 +248,14 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
                 btrfs_set_super_blocks_used(info->disk_super,
                                             super_blocks_used - num_blocks);
-                ret = btrfs_del_item(trans, extent_root, &path);
+                ret = btrfs_del_item(trans, extent_root, path);
                 if (extent_root->fs_info->last_insert.objectid > blocknr)
                         extent_root->fs_info->last_insert.objectid = blocknr;
                 if (ret)
                         BUG();
         }
-        btrfs_release_path(extent_root, &path);
+        btrfs_release_path(extent_root, path);
+        btrfs_free_path(path);
         finish_current_insert(trans, extent_root);
         return ret;
 }
@@ -319,7 +328,7 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                             *orig_root, u64 num_blocks, u64 search_start, u64
                             search_end, struct btrfs_key *ins)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_key key;
         int ret;
         u64 hole_size = 0;
@@ -339,24 +348,25 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 
         ins->flags = 0;
         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
+        path = btrfs_alloc_path();
 
 check_failed:
-        btrfs_init_path(&path);
+        btrfs_init_path(path);
         ins->objectid = search_start;
         ins->offset = 0;
         start_found = 0;
-        ret = btrfs_search_slot(trans, root, ins, &path, 0, 0);
+        ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
         if (ret < 0)
                 goto error;
 
-        if (path.slots[0] > 0)
-                path.slots[0]--;
+        if (path->slots[0] > 0)
+                path->slots[0]--;
 
         while (1) {
-                l = btrfs_buffer_leaf(path.nodes[0]);
-                slot = path.slots[0];
+                l = btrfs_buffer_leaf(path->nodes[0]);
+                slot = path->slots[0];
                 if (slot >= btrfs_header_nritems(&l->header)) {
-                        ret = btrfs_next_leaf(root, &path);
+                        ret = btrfs_next_leaf(root, path);
                         if (ret == 0)
                                 continue;
                         if (ret < 0)
@@ -387,14 +397,14 @@ check_failed:
                 }
                 start_found = 1;
                 last_block = key.objectid + key.offset;
-                path.slots[0]++;
+                path->slots[0]++;
         }
         // FIXME -ENOSPC
 check_pending:
         /* we have to make sure we didn't find an extent that has already
          * been allocated by the map tree or the original allocation
          */
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
         BUG_ON(ins->objectid < search_start);
         for (test_block = ins->objectid;
              test_block < ins->objectid + total_needed; test_block++) {
@@ -410,9 +420,11 @@ check_pending:
         root->fs_info->current_insert.flags = 0;
         root->fs_info->last_insert.objectid = ins->objectid;
         ins->offset = num_blocks;
+        btrfs_free_path(path);
         return 0;
 error:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
@@ -533,6 +545,8 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
         int ret;
         u32 refs;
 
+        WARN_ON(*level < 0);
+        WARN_ON(*level >= BTRFS_MAX_LEVEL);
         ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr,
                                1, &refs);
         BUG_ON(ret);
@@ -542,6 +556,8 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
          * walk down to the last node level and free all the leaves
          */
         while(*level >= 0) {
+                WARN_ON(*level < 0);
+                WARN_ON(*level >= BTRFS_MAX_LEVEL);
                 cur = path->nodes[*level];
                 if (btrfs_header_level(btrfs_buffer_header(cur)) != *level)
                         WARN_ON(1);
@@ -564,6 +580,7 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
                         continue;
                 }
                 next = read_tree_block(root, blocknr);
+                WARN_ON(*level <= 0);
                 if (path->nodes[*level-1])
                         btrfs_block_release(root, path->nodes[*level-1]);
                 path->nodes[*level-1] = next;
@@ -571,6 +588,8 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
                 path->slots[*level] = 0;
         }
 out:
+        WARN_ON(*level < 0);
+        WARN_ON(*level >= BTRFS_MAX_LEVEL);
         ret = btrfs_free_extent(trans, root,
                                 path->nodes[*level]->b_blocknr, 1, 1);
         btrfs_block_release(root, path->nodes[*level]);
@@ -622,33 +641,36 @@ int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
         int ret = 0;
         int wret;
         int level;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         int i;
         int orig_level;
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
 
         level = btrfs_header_level(btrfs_buffer_header(snap));
         orig_level = level;
-        path.nodes[level] = snap;
-        path.slots[level] = 0;
+        path->nodes[level] = snap;
+        path->slots[level] = 0;
         while(1) {
-                wret = walk_down_tree(trans, root, &path, &level);
+                wret = walk_down_tree(trans, root, path, &level);
                 if (wret > 0)
                         break;
                 if (wret < 0)
                         ret = wret;
 
-                wret = walk_up_tree(trans, root, &path, &level);
+                wret = walk_up_tree(trans, root, path, &level);
                 if (wret > 0)
                         break;
                 if (wret < 0)
                         ret = wret;
         }
         for (i = 0; i <= orig_level; i++) {
-                if (path.nodes[i]) {
-                        btrfs_block_release(root, path.nodes[i]);
+                if (path->nodes[i]) {
+                        btrfs_block_release(root, path->nodes[i]);
                 }
         }
+        btrfs_free_path(path);
         return ret;
 }
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index c3992b7b0c60..e7510ac5559d 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -13,9 +13,11 @@ int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
         int ret = 0;
         struct btrfs_file_extent_item *item;
         struct btrfs_key file_key;
-        struct btrfs_path path;
+        struct btrfs_path *path;
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
         ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block,
                                  (u64)-1, objectid, &ins);
         BUG_ON(ret);
@@ -24,19 +26,20 @@ int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
         file_key.flags = 0;
         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
 
-        ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
+        ret = btrfs_insert_empty_item(trans, root, path, &file_key,
                                       sizeof(*item));
         BUG_ON(ret);
-        item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+        item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                               struct btrfs_file_extent_item);
         btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
         btrfs_set_file_extent_disk_num_blocks(item, ins.offset);
         btrfs_set_file_extent_offset(item, 0);
         btrfs_set_file_extent_num_blocks(item, ins.offset);
         btrfs_set_file_extent_generation(item, trans->transid);
-        btrfs_mark_buffer_dirty(path.nodes[0]);
+        btrfs_mark_buffer_dirty(path->nodes[0]);
         *result = ins.objectid;
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return 0;
 }
 
@@ -65,25 +68,28 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 {
         int ret;
         struct btrfs_key file_key;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_csum_item *item;
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
         file_key.objectid = objectid;
         file_key.offset = offset;
         file_key.flags = 0;
         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
-        ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
+        ret = btrfs_insert_empty_item(trans, root, path, &file_key,
                                       BTRFS_CSUM_SIZE);
         if (ret != 0 && ret != -EEXIST)
                 goto fail;
-        item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+        item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                               struct btrfs_csum_item);
         ret = 0;
         ret = btrfs_csum_data(root, data, len, item->csum);
-        btrfs_mark_buffer_dirty(path.nodes[0]);
+        btrfs_mark_buffer_dirty(path->nodes[0]);
 fail:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
@@ -93,19 +99,21 @@ int btrfs_csum_verify_file_block(struct btrfs_root *root,
 {
         int ret;
         struct btrfs_key file_key;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_csum_item *item;
         char result[BTRFS_CSUM_SIZE];
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
         file_key.objectid = objectid;
         file_key.offset = offset;
         file_key.flags = 0;
         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
-        ret = btrfs_search_slot(NULL, root, &file_key, &path, 0, 0);
+        ret = btrfs_search_slot(NULL, root, &file_key, path, 0, 0);
         if (ret)
                 goto fail;
-        item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+        item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                               struct btrfs_csum_item);
         ret = 0;
         ret = btrfs_csum_data(root, data, len, result);
@@ -113,7 +121,8 @@ int btrfs_csum_verify_file_block(struct btrfs_root *root,
         if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
                 ret = 1;
 fail:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index 8d8c26a6c1a0..6bfa980790c2 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -7,7 +7,7 @@ int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
                        *root, u64 objectid, struct btrfs_inode_item
                        *inode_item)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_key key;
         int ret;
         key.objectid = objectid;
@@ -15,10 +15,13 @@ int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
         key.offset = 0;
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
         ret = btrfs_insert_item(trans, root, &key, inode_item,
                                 sizeof(*inode_item));
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index f37dab87de16..ddc1c13a5352 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -6,7 +6,7 @@
 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
                         struct btrfs_root_item *item, struct btrfs_key *key)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_key search_key;
         struct btrfs_leaf *l;
         int ret;
@@ -16,14 +16,16 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
         search_key.flags = (u32)-1;
         search_key.offset = (u32)-1;
 
-        btrfs_init_path(&path);
-        ret = btrfs_search_slot(NULL, root, &search_key, &path, 0, 0);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
+        ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
         if (ret < 0)
                 goto out;
         BUG_ON(ret == 0);
-        l = btrfs_buffer_leaf(path.nodes[0]);
-        BUG_ON(path.slots[0] == 0);
-        slot = path.slots[0] - 1;
+        l = btrfs_buffer_leaf(path->nodes[0]);
+        BUG_ON(path->slots[0] == 0);
+        slot = path->slots[0] - 1;
         if (btrfs_disk_key_objectid(&l->items[slot].key) != objectid) {
                 ret = 1;
                 goto out;
@@ -31,9 +33,10 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
         memcpy(item, btrfs_item_ptr(l, slot, struct btrfs_root_item),
                 sizeof(*item));
         btrfs_disk_key_to_cpu(key, &l->items[slot].key);
-        btrfs_release_path(root, &path);
         ret = 0;
 out:
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
@@ -41,24 +44,27 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root, struct btrfs_key *key, struct btrfs_root_item
                       *item)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_leaf *l;
         int ret;
         int slot;
         struct btrfs_root_item *update_item;
 
-        btrfs_init_path(&path);
-        ret = btrfs_search_slot(trans, root, key, &path, 0, 1);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
+        ret = btrfs_search_slot(trans, root, key, path, 0, 1);
         if (ret < 0)
                 goto out;
         BUG_ON(ret != 0);
-        l = btrfs_buffer_leaf(path.nodes[0]);
-        slot = path.slots[0];
+        l = btrfs_buffer_leaf(path->nodes[0]);
+        slot = path->slots[0];
         update_item = btrfs_item_ptr(l, slot, struct btrfs_root_item);
         btrfs_memcpy(root, l, update_item, item, sizeof(*item));
-        btrfs_mark_buffer_dirty(path.nodes[0]);
+        btrfs_mark_buffer_dirty(path->nodes[0]);
 out:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
@@ -75,16 +81,19 @@ int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                    struct btrfs_key *key)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         int ret;
 
-        btrfs_init_path(&path);
-        ret = btrfs_search_slot(trans, root, key, &path, -1, 1);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
+        ret = btrfs_search_slot(trans, root, key, path, -1, 1);
         if (ret < 0)
                 goto out;
         BUG_ON(ret != 0);
-        ret = btrfs_del_item(trans, root, &path);
+        ret = btrfs_del_item(trans, root, path);
 out:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 6969b672b570..c260fcad17b3 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -35,25 +35,27 @@ static int check_inode(struct inode *inode)
 
 static void btrfs_read_locked_inode(struct inode *inode)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_inode_item *inode_item;
         struct btrfs_root *root = btrfs_sb(inode->i_sb);
         int ret;
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
         mutex_lock(&root->fs_info->fs_mutex);
 
         check_inode(inode);
-        ret = btrfs_lookup_inode(NULL, root, &path, inode->i_ino, 0);
+        ret = btrfs_lookup_inode(NULL, root, path, inode->i_ino, 0);
         if (ret) {
-                btrfs_release_path(root, &path);
+                btrfs_release_path(root, path);
                 mutex_unlock(&root->fs_info->fs_mutex);
                 make_bad_inode(inode);
                 return;
         }
         check_inode(inode);
-        inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
-                                  path.slots[0],
+        inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
+                                  path->slots[0],
                                   struct btrfs_inode_item);
 
         inode->i_mode = btrfs_inode_mode(inode_item);
@@ -69,7 +71,11 @@ static void btrfs_read_locked_inode(struct inode *inode)
         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(&inode_item->ctime);
         inode->i_blocks = btrfs_inode_nblocks(inode_item);
         inode->i_generation = btrfs_inode_generation(inode_item);
-        btrfs_release_path(root, &path);
+
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
+        inode_item = NULL;
+
         mutex_unlock(&root->fs_info->fs_mutex);
         check_inode(inode);
         switch (inode->i_mode & S_IFMT) {
@@ -101,15 +107,17 @@ static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
                               struct inode *dir,
                               struct dentry *dentry)
 {
-        struct btrfs_path path;
+        struct btrfs_path *path;
         const char *name = dentry->d_name.name;
         int name_len = dentry->d_name.len;
         int ret;
         u64 objectid;
         struct btrfs_dir_item *di;
 
-        btrfs_init_path(&path);
-        ret = btrfs_lookup_dir_item(trans, root, &path, dir->i_ino,
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
+        ret = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
                                     name, name_len, -1);
         if (ret < 0)
                 goto err;
@@ -117,15 +125,16 @@ static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
                 ret = -ENOENT;
                 goto err;
         }
-        di = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+        di = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                             struct btrfs_dir_item);
         objectid = btrfs_dir_objectid(di);
 
-        ret = btrfs_del_item(trans, root, &path);
+        ret = btrfs_del_item(trans, root, path);
         BUG_ON(ret);
         dentry->d_inode->i_ctime = dir->i_ctime;
 err:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         if (ret == 0)
                 inode_dec_link_count(dentry->d_inode);
         return ret;
@@ -152,30 +161,32 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
         int err;
         int ret;
         struct btrfs_root *root = btrfs_sb(dir->i_sb);
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_key key;
         struct btrfs_trans_handle *trans;
         struct btrfs_disk_key *found_key;
         struct btrfs_leaf *leaf;
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
         mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         key.objectid = inode->i_ino;
         key.offset = (u64)-1;
         key.flags = 0;
         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
-        ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
+        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
         if (ret < 0) {
                 err = ret;
                 goto out;
         }
 
         BUG_ON(ret == 0);
-        BUG_ON(path.slots[0] == 0);
-        path.slots[0]--;
-        leaf = btrfs_buffer_leaf(path.nodes[0]);
-        found_key = &leaf->items[path.slots[0]].key;
+        BUG_ON(path->slots[0] == 0);
+        path->slots[0]--;
+        leaf = btrfs_buffer_leaf(path->nodes[0]);
+        found_key = &leaf->items[path->slots[0]].key;
         if (btrfs_disk_key_objectid(found_key) != inode->i_ino) {
                 err = -ENOENT;
                 goto out;
@@ -185,11 +196,11 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
                 err = -ENOTEMPTY;
                 goto out;
         }
-        ret = btrfs_del_item(trans, root, &path);
+        ret = btrfs_del_item(trans, root, path);
         BUG_ON(ret);
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
         key.offset = 1;
-        ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
+        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
         if (ret < 0) {
                 err = ret;
                 goto out;
@@ -198,12 +209,13 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
                 err = -ENOTEMPTY;
                 goto out;
         }
-        ret = btrfs_del_item(trans, root, &path);
+        ret = btrfs_del_item(trans, root, path);
         if (ret) {
                 err = ret;
                 goto out;
         }
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
 
         /* now the directory is empty */
         err = btrfs_unlink_trans(trans, root, dir, dentry);
@@ -223,33 +235,36 @@ static int btrfs_free_inode(struct btrfs_trans_handle *trans,
                             struct inode *inode)
 {
         u64 objectid = inode->i_ino;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_inode_map_item *map;
         struct btrfs_key stat_data_key;
         int ret;
+
         clear_inode(inode);
-        btrfs_init_path(&path);
-        ret = btrfs_lookup_inode_map(trans, root, &path, objectid, -1);
+
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
+        ret = btrfs_lookup_inode_map(trans, root, path, objectid, -1);
         if (ret) {
                 if (ret > 0)
                         ret = -ENOENT;
-                btrfs_release_path(root, &path);
                 goto error;
         }
-        map = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+        map = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                             struct btrfs_inode_map_item);
         btrfs_disk_key_to_cpu(&stat_data_key, &map->key);
-        ret = btrfs_del_item(trans, root->fs_info->inode_root, &path);
+        ret = btrfs_del_item(trans, root->fs_info->inode_root, path);
         BUG_ON(ret);
-        btrfs_release_path(root, &path);
-        btrfs_init_path(&path);
+        btrfs_release_path(root, path);
 
-        ret = btrfs_lookup_inode(trans, root, &path, objectid, -1);
+        ret = btrfs_lookup_inode(trans, root, path, objectid, -1);
         BUG_ON(ret);
-        ret = btrfs_del_item(trans, root, &path);
+        ret = btrfs_del_item(trans, root, path);
         BUG_ON(ret);
-        btrfs_release_path(root, &path);
 error:
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
@@ -258,7 +273,7 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
                                    struct inode *inode)
 {
         int ret;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_key key;
         struct btrfs_disk_key *found_key;
         struct btrfs_leaf *leaf;
@@ -267,24 +282,25 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
         u64 extent_num_blocks = 0;
         int found_extent;
 
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
         /* FIXME, add redo link to tree so we don't leak on crash */
         key.objectid = inode->i_ino;
         key.offset = (u64)-1;
         key.flags = 0;
         btrfs_set_key_type(&key, BTRFS_CSUM_ITEM_KEY);
         while(1) {
-                btrfs_init_path(&path);
-                ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
+                btrfs_init_path(path);
+                ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
                 if (ret < 0) {
-                        btrfs_release_path(root, &path);
                         goto error;
                 }
                 if (ret > 0) {
-                        BUG_ON(path.slots[0] == 0);
-                        path.slots[0]--;
+                        BUG_ON(path->slots[0] == 0);
+                        path->slots[0]--;
                 }
-                leaf = btrfs_buffer_leaf(path.nodes[0]);
-                found_key = &leaf->items[path.slots[0]].key;
+                leaf = btrfs_buffer_leaf(path->nodes[0]);
+                found_key = &leaf->items[path->slots[0]].key;
                 if (btrfs_disk_key_objectid(found_key) != inode->i_ino)
                         break;
                 if (btrfs_disk_key_type(found_key) != BTRFS_CSUM_ITEM_KEY &&
@@ -293,8 +309,8 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
                 if (btrfs_disk_key_offset(found_key) < inode->i_size)
                         break;
                 if (btrfs_disk_key_type(found_key) == BTRFS_EXTENT_DATA_KEY) {
-                        fi = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
-                                            path.slots[0],
+                        fi = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
+                                            path->slots[0],
                                             struct btrfs_file_extent_item);
                         extent_start = btrfs_file_extent_disk_blocknr(fi);
                         extent_num_blocks =
@@ -305,18 +321,19 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
                 } else {
                         found_extent = 0;
                 }
-                ret = btrfs_del_item(trans, root, &path);
+                ret = btrfs_del_item(trans, root, path);
                 BUG_ON(ret);
-                btrfs_release_path(root, &path);
+                btrfs_release_path(root, path);
                 if (found_extent) {
                         ret = btrfs_free_extent(trans, root, extent_start,
                                                 extent_num_blocks, 0);
                         BUG_ON(ret);
                 }
         }
-        btrfs_release_path(root, &path);
         ret = 0;
 error:
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         return ret;
 }
 
@@ -351,23 +368,26 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
         const char *name = dentry->d_name.name;
         int namelen = dentry->d_name.len;
         struct btrfs_dir_item *di;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_root *root = btrfs_sb(dir->i_sb);
         int ret;
 
-        btrfs_init_path(&path);
-        ret = btrfs_lookup_dir_item(NULL, root, &path, dir->i_ino, name,
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
+        ret = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
                                     namelen, 0);
-        if (ret || !btrfs_match_dir_item_name(root, &path, name, namelen)) {
+        if (ret || !btrfs_match_dir_item_name(root, path, name, namelen)) {
                 *ino = 0;
                 ret = 0;
                 goto out;
         }
-        di = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+        di = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                             struct btrfs_dir_item);
         *ino = btrfs_dir_objectid(di);
 out:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         check_inode(dir);
         return ret;
 }
@@ -405,7 +425,7 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
         struct btrfs_item *item;
         struct btrfs_dir_item *di;
         struct btrfs_key key;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         int ret;
         u32 nritems;
         struct btrfs_leaf *leaf;
@@ -419,27 +439,28 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
         key.flags = 0;
         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
         key.offset = filp->f_pos;
-        btrfs_init_path(&path);
-        ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+        path = btrfs_alloc_path();
+        btrfs_init_path(path);
+        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
         if (ret < 0) {
                 goto err;
         }
         advance = 0;
         while(1) {
-                leaf = btrfs_buffer_leaf(path.nodes[0]);
+                leaf = btrfs_buffer_leaf(path->nodes[0]);
                 nritems = btrfs_header_nritems(&leaf->header);
-                slot = path.slots[0];
+                slot = path->slots[0];
                 if (advance || slot >= nritems) {
                         if (slot >= nritems -1) {
-                                ret = btrfs_next_leaf(root, &path);
+                                ret = btrfs_next_leaf(root, path);
                                 if (ret)
                                         break;
-                                leaf = btrfs_buffer_leaf(path.nodes[0]);
+                                leaf = btrfs_buffer_leaf(path->nodes[0]);
                                 nritems = btrfs_header_nritems(&leaf->header);
-                                slot = path.slots[0];
+                                slot = path->slots[0];
                         } else {
                                 slot++;
-                                path.slots[0]++;
+                                path->slots[0]++;
                         }
                 }
                 advance = 1;
@@ -465,7 +486,8 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
         }
         ret = 0;
 err:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         mutex_unlock(&root->fs_info->fs_mutex);
         return ret;
 }
@@ -548,26 +570,29 @@ static int btrfs_update_inode(struct btrfs_trans_handle *trans,
                               struct inode *inode)
 {
         struct btrfs_inode_item *inode_item;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         int ret;
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
 
-        ret = btrfs_lookup_inode(trans, root, &path, inode->i_ino, 1);
+        ret = btrfs_lookup_inode(trans, root, path, inode->i_ino, 1);
         if (ret) {
                 if (ret > 0)
                         ret = -ENOENT;
                 goto failed;
         }
 
-        inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
-                                  path.slots[0],
+        inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
+                                  path->slots[0],
                                   struct btrfs_inode_item);
 
         fill_inode_item(inode_item, inode);
-        btrfs_mark_buffer_dirty(path.nodes[0]);
+        btrfs_mark_buffer_dirty(path->nodes[0]);
 failed:
-        btrfs_release_path(root, &path);
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         check_inode(inode);
         return 0;
 }
@@ -799,38 +824,39 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
         u64 extent_start = 0;
         u64 extent_end = 0;
         u64 objectid = inode->i_ino;
-        struct btrfs_path path;
+        struct btrfs_path *path;
         struct btrfs_root *root = btrfs_sb(inode->i_sb);
         struct btrfs_trans_handle *trans = NULL;
         struct btrfs_file_extent_item *item;
         struct btrfs_leaf *leaf;
         struct btrfs_disk_key *found_key;
 
-        btrfs_init_path(&path);
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        btrfs_init_path(path);
         if (create)
                 trans = btrfs_start_transaction(root, 1);
 
 
-        ret = btrfs_lookup_file_extent(trans, root, &path,
+        ret = btrfs_lookup_file_extent(trans, root, path,
                                        inode->i_ino,
                                        iblock << inode->i_blkbits, 0);
         if (ret < 0) {
-                btrfs_release_path(root, &path);
                 err = ret;
                 goto out;
         }
 
         if (ret != 0) {
-                if (path.slots[0] == 0) {
-                        btrfs_release_path(root, &path);
+                if (path->slots[0] == 0) {
+                        btrfs_release_path(root, path);
                         goto allocate;
                 }
-                path.slots[0]--;
+                path->slots[0]--;
         }
 
-        item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+        item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                               struct btrfs_file_extent_item);
-        leaf = btrfs_buffer_leaf(path.nodes[0]);
+        leaf = btrfs_buffer_leaf(path->nodes[0]);
         blocknr = btrfs_file_extent_disk_blocknr(item);
         blocknr += btrfs_file_extent_offset(item);
 
@@ -838,25 +864,23 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
         if (ret == 0) {
                 err = 0;
                 map_bh(result, inode->i_sb, blocknr);
-                btrfs_release_path(root, &path);
                 goto out;
         }
 
         /* are we inside the extent that was found? */
-        found_key = &leaf->items[path.slots[0]].key;
+        found_key = &leaf->items[path->slots[0]].key;
         if (btrfs_disk_key_objectid(found_key) != objectid ||
             btrfs_disk_key_type(found_key) != BTRFS_EXTENT_DATA_KEY) {
                 extent_end = 0;
                 extent_start = 0;
-                btrfs_release_path(root, &path);
+                btrfs_release_path(root, path);
                 goto allocate;
         }
 
-        extent_start = btrfs_disk_key_offset(&leaf->items[path.slots[0]].key);
+        extent_start = btrfs_disk_key_offset(&leaf->items[path->slots[0]].key);
         extent_start = extent_start >> inode->i_blkbits;
         extent_start += btrfs_file_extent_offset(item);
         extent_end = extent_start + btrfs_file_extent_num_blocks(item);
-        btrfs_release_path(root, &path);
         if (iblock >= extent_start && iblock < extent_end) {
                 err = 0;
                 map_bh(result, inode->i_sb, blocknr + iblock - extent_start);
@@ -880,6 +904,8 @@ allocate:
         map_bh(result, inode->i_sb, blocknr);
 
 out:
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
         if (trans)
                 btrfs_end_transaction(trans, root);
         return err;