Yan Zheng
2008-Jan-03 05:04 UTC
[Btrfs-devel][PATCH]Add a helper that finds previous extent item
Hello,
This patch adds a helper function that finds previous extent item to
extent-tree.c. The helper is based on find_overlapping_extent.
Regards
YZ
---
diff -r 1953535fb49b extent-tree.c
--- a/extent-tree.c Wed Jan 02 10:01:11 2008 -0500
+++ b/extent-tree.c Thu Jan 03 20:31:58 2008 +0800
@@ -34,6 +34,29 @@ static int del_pending_extents(struct bt
static int del_pending_extents(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root);
+static int find_previous_extent(struct btrfs_root *root,
+ struct btrfs_path *path)
+{
+ 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 != 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)
+ return 0;
+ }
+ return 1;
+}
+
static int cache_block_group(struct btrfs_root *root,
struct btrfs_block_group_cache *block_group)
{
@@ -68,12 +91,18 @@ static int cache_block_group(struct btrf
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-
if (ret < 0)
return ret;
- if (ret && path->slots[0] > 0)
- path->slots[0]--;
+ ret = find_previous_extent(root, path);
+ if (ret < 0)
+ return ret;
+ if (ret == 0) {
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid + key.offset > first_free)
+ first_free = key.objectid + key.offset;
+ }
while(1) {
leaf = path->nodes[0];
@@ -91,9 +120,6 @@ static int cache_block_group(struct btrf
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid < block_group->key.objectid) {
- if (btrfs_key_type(&key) != BTRFS_EXTENT_REF_KEY &&
- key.objectid + key.offset > first_free)
- first_free = key.objectid + key.offset;
goto next;
}
@@ -164,8 +190,7 @@ struct btrfs_block_group_cache *btrfs_lo
}
static u64 find_search_start(struct btrfs_root *root,
struct btrfs_block_group_cache **cache_ret,
- u64 search_start, int num,
- int data, int full_scan)
+ u64 search_start, int num, int data)
{
int ret;
struct btrfs_block_group_cache *cache = *cache_ret;
@@ -1424,7 +1449,7 @@ check_failed:
orig_search_start);
}
search_start = find_search_start(root, &block_group, search_start,
- total_needed, data, full_scan);
+ total_needed, data);
search_start = stripe_align(root, search_start);
cached_start = search_start;
btrfs_init_path(path);
@@ -1437,34 +1462,13 @@ check_failed:
if (ret < 0)
goto error;
- if (path->slots[0] > 0) {
- path->slots[0]--;
- }
+ ret = find_previous_extent(root, path);
+ if (ret < 0)
+ goto error;
l = path->nodes[0];
btrfs_item_key_to_cpu(l, &key, path->slots[0]);
- /*
- * walk backwards to find the first extent item key
- */
- while(btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
- if (path->slots[0] == 0) {
- ret = btrfs_prev_leaf(root, path);
- if (ret != 0) {
- ret = btrfs_search_slot(trans, root, ins,
- path, 0, 0);
- if (ret < 0)
- goto error;
- if (path->slots[0] > 0)
- path->slots[0]--;
- break;
- }
- } else {
- path->slots[0]--;
- }
- l = path->nodes[0];
- btrfs_item_key_to_cpu(l, &key, path->slots[0]);
- }
while (1) {
l = path->nodes[0];
slot = path->slots[0];
Yan Zheng
2008-Jan-03 07:24 UTC
[Btrfs-devel][PATCH]Add a helper that finds previous extent item
Hello,
This is the updated version. In addition, the patch remove a unused
parameter from find_search_start's parameter list.
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
@@ -34,6 +34,29 @@ static int del_pending_extents(struct bt
static int del_pending_extents(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root);
+static int find_previous_extent(struct btrfs_root *root,
+ struct btrfs_path *path)
+{
+ 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 != 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)
+ return 0;
+ }
+ return 1;
+}
+
static int cache_block_group(struct btrfs_root *root,
struct btrfs_block_group_cache *block_group)
{
@@ -68,12 +91,18 @@ static int cache_block_group(struct btrf
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-
if (ret < 0)
return ret;
- if (ret && path->slots[0] > 0)
- path->slots[0]--;
+ ret = find_previous_extent(root, path);
+ if (ret < 0)
+ return ret;
+ if (ret == 0) {
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid + key.offset > first_free)
+ first_free = key.objectid + key.offset;
+ }
while(1) {
leaf = path->nodes[0];
@@ -91,9 +120,6 @@ static int cache_block_group(struct btrf
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid < block_group->key.objectid) {
- if (btrfs_key_type(&key) != BTRFS_EXTENT_REF_KEY &&
- key.objectid + key.offset > first_free)
- first_free = key.objectid + key.offset;
goto next;
}
@@ -165,8 +191,7 @@ struct btrfs_block_group_cache *btrfs_lo
static u64 noinline find_search_start(struct btrfs_root *root,
struct btrfs_block_group_cache **cache_ret,
- u64 search_start, int num,
- int data, int full_scan)
+ u64 search_start, int num, int data)
{
int ret;
struct btrfs_block_group_cache *cache = *cache_ret;
@@ -771,7 +796,6 @@ out:
out:
btrfs_free_path(path);
return total_count;
-
}
int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
@@ -1422,7 +1446,7 @@ check_failed:
orig_search_start);
}
search_start = find_search_start(root, &block_group, search_start,
- total_needed, data, full_scan);
+ total_needed, data);
search_start = stripe_align(root, search_start);
cached_start = search_start;
btrfs_init_path(path);
@@ -1435,34 +1459,13 @@ check_failed:
if (ret < 0)
goto error;
- if (path->slots[0] > 0) {
- path->slots[0]--;
- }
+ ret = find_previous_extent(root, path);
+ if (ret < 0)
+ goto error;
l = path->nodes[0];
btrfs_item_key_to_cpu(l, &key, path->slots[0]);
- /*
- * walk backwards to find the first extent item key
- */
- while(btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
- if (path->slots[0] == 0) {
- ret = btrfs_prev_leaf(root, path);
- if (ret != 0) {
- ret = btrfs_search_slot(trans, root, ins,
- path, 0, 0);
- if (ret < 0)
- goto error;
- if (path->slots[0] > 0)
- path->slots[0]--;
- break;
- }
- } else {
- path->slots[0]--;
- }
- l = path->nodes[0];
- btrfs_item_key_to_cpu(l, &key, path->slots[0]);
- }
while (1) {
l = path->nodes[0];
slot = path->slots[0];