Yan Zheng
2008-Jan-03 07:48 UTC
[Btrfs-devel][PATCH]Properly handle overlapping extent in shrink_extent_tree
Hello,
The patch fixes the overlapping extent issue in shrink_extent_tree.
It checks whether there is an overlapping extent by using
find_previous_extent. If there is an overlapping extent, it setups
key.objectid and cur_byte properly. ( I rearrange some codes in
shrink_extent_tree. If you don't like these changes, please tell me,
I will remove them)
Regards
YZ
---
diff -r 159e31b1d943 extent-tree.c
--- a/extent-tree.c Thu Jan 03 10:01:48 2008 -0500
+++ b/extent-tree.c Thu Jan 03 23:13:01 2008 +0800
@@ -2325,36 +2328,6 @@ out:
return ret;
}
-static int find_overlapping_extent(struct btrfs_root *root,
- struct btrfs_path *path, u64 new_size)
-{
- struct btrfs_key found_key;
- struct extent_buffer *leaf;
- int ret;
-
- while(1) {
- if (path->slots[0] == 0) {
- ret = btrfs_prev_leaf(root, path);
- if (ret == 1) {
- return 1;
- }
- if (ret < 0)
- return ret;
- } else {
- path->slots[0]--;
- }
- leaf = path->nodes[0];
- btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
- if (found_key.type == BTRFS_EXTENT_ITEM_KEY) {
- if (found_key.objectid + found_key.offset > new_size)
- return 0;
- else
- return 1;
- }
- }
- return 1;
-}
-
int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
{
struct btrfs_trans_handle *trans;
@@ -2369,7 +2342,6 @@ int btrfs_shrink_extent_tree(struct btrf
struct extent_buffer *leaf;
u32 nritems;
int ret;
- int slot;
btrfs_set_super_total_bytes(&info->super_copy, new_size);
block_group_cache = &info->block_group_cache;
@@ -2380,48 +2352,55 @@ again:
again:
total_found = 0;
key.objectid = new_size;
- cur_byte = key.objectid;
key.offset = 0;
key.type = 0;
+ cur_byte = key.objectid;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ ret = find_previous_extent(root, path);
+ if (ret < 0)
+ goto out;
+ if (ret == 0) {
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (found_key.objectid + found_key.offset > new_size) {
+ cur_byte = found_key.objectid;
+ key.objectid = cur_byte;
+ }
+ }
+ btrfs_release_path(root, path);
+
while(1) {
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
next:
- leaf = path->nodes[0];
- if (key.objectid == new_size - 1) {
- ret = find_overlapping_extent(root, path, new_size);
- if (ret != 0) {
- btrfs_release_path(root, path);
- ret = btrfs_search_slot(NULL, root, &key,
- path, 0, 0);
- if (ret < 0)
- goto out;
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ goto out;
+ if (ret == 1) {
+ ret = 0;
+ break;
}
- }
- nritems = btrfs_header_nritems(leaf);
- ret = 0;
- slot = path->slots[0];
- if (slot < nritems)
- btrfs_item_key_to_cpu(leaf, &found_key, slot);
- if (slot == nritems ||
- btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY) {
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ }
+
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
+ found_key.objectid + found_key.offset <= cur_byte) {
path->slots[0]++;
- if (path->slots[0] >= nritems) {
- ret = btrfs_next_leaf(root, path);
- if (ret < 0)
- goto out;
- if (ret == 1) {
- ret = 0;
- break;
- }
- }
goto next;
}
- btrfs_item_key_to_cpu(leaf, &found_key, slot);
- if (found_key.objectid + found_key.offset <= cur_byte)
- continue;
+
total_found++;
cur_byte = found_key.objectid + found_key.offset;
key.objectid = cur_byte;
@@ -2454,33 +2433,30 @@ next:
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0)
goto out;
-bg_next:
+
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
- ret = 0;
- slot = path->slots[0];
- if (slot < nritems)
- btrfs_item_key_to_cpu(leaf, &found_key, slot);
- if (slot == nritems ||
- btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {
- if (slot < nritems) {
- printk("shrinker found key %Lu %u %Lu\n",
- found_key.objectid, found_key.type,
- found_key.offset);
- path->slots[0]++;
+bg_next:
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ break;
+ if (ret == 1) {
+ ret = 0;
+ break;
}
- if (path->slots[0] >= nritems) {
- ret = btrfs_next_leaf(root, path);
- if (ret < 0)
- break;
- if (ret == 1) {
- ret = 0;
- break;
- }
- }
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ }
+
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {
+ printk("shrinker found key %Lu %u %Lu\n",
+ found_key.objectid, found_key.type,
+ found_key.offset);
+ path->slots[0]++;
goto bg_next;
}
- btrfs_item_key_to_cpu(leaf, &found_key, slot);
ret = get_state_private(&info->block_group_cache,
found_key.objectid, &ptr);
if (!ret)