Btrfs: merge on the way down during deletes
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 2732399..df4a19d 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -10,11 +10,10 @@
int level);
static int split_leaf(struct ctree_root *root, struct ctree_path *path,
int data_size);
-static int push_node_left(struct ctree_root *root, struct ctree_path *path,
- int level);
-static int push_node_right(struct ctree_root *root,
- struct ctree_path *path, int level);
-static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level);
+static int push_node_left(struct ctree_root *root, struct tree_buffer *dst,
+ struct tree_buffer *src);
+static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level,
+ int slot);
inline void init_path(struct ctree_path *p)
{
@@ -192,6 +191,138 @@
return -1;
}
+struct tree_buffer *read_node_slot(struct ctree_root *root,
+ struct tree_buffer *parent_buf,
+ int slot)
+{
+ struct node *node = &parent_buf->node;
+ if (slot < 0)
+ return NULL;
+ if (slot >= node->header.nritems)
+ return NULL;
+ return read_tree_block(root, node->blockptrs[slot]);
+}
+
+static int balance_level(struct ctree_root *root, struct ctree_path *path,
+ int level)
+{
+ struct tree_buffer *right_buf;
+ struct tree_buffer *mid_buf;
+ struct tree_buffer *left_buf;
+ struct tree_buffer *parent_buf = NULL;
+ struct node *right = NULL;
+ struct node *mid;
+ struct node *left = NULL;
+ struct node *parent = NULL;
+ int ret = 0;
+ int wret;
+ int pslot;
+ int used = 0;
+ int count;
+ int orig_slot = path->slots[level];
+
+ if (level == 0)
+ return 0;
+
+ mid_buf = path->nodes[level];
+ mid = &mid_buf->node;
+ if (level < MAX_LEVEL - 1)
+ parent_buf = path->nodes[level + 1];
+ pslot = path->slots[level + 1];
+
+ if (!parent_buf) {
+ struct tree_buffer *child;
+ u64 blocknr = mid_buf->blocknr;
+
+ if (mid->header.nritems != 1)
+ return 0;
+
+ /* promote the child to a root */
+ child = read_node_slot(root, mid_buf, 0);
+ BUG_ON(!child);
+ root->node = child;
+ path->nodes[level] = NULL;
+ /* once for the path */
+ tree_block_release(root, mid_buf);
+ /* once for the root ptr */
+ tree_block_release(root, mid_buf);
+ return free_extent(root, blocknr, 1);
+ }
+ parent = &parent_buf->node;
+
+ if (mid->header.nritems > NODEPTRS_PER_BLOCK / 4)
+ return 0;
+
+ // print_tree(root, root->node);
+ left_buf = read_node_slot(root, parent_buf, pslot - 1);
+ right_buf = read_node_slot(root, parent_buf, pslot + 1);
+ if (right_buf) {
+ right = &right_buf->node;
+ used = right->header.nritems;
+ count = 1;
+ }
+ if (left_buf) {
+ left = &left_buf->node;
+ used += left->header.nritems;
+ orig_slot += left->header.nritems;
+ count++;
+ }
+ if (left_buf)
+ push_node_left(root, left_buf, mid_buf);
+ if (right_buf) {
+ push_node_left(root, mid_buf, right_buf);
+ if (right->header.nritems == 0) {
+ u64 blocknr = right_buf->blocknr;
+ tree_block_release(root, right_buf);
+ right_buf = NULL;
+ right = NULL;
+ wret = del_ptr(root, path, level + 1, pslot + 1);
+ if (wret)
+ ret = wret;
+ wret = free_extent(root, blocknr, 1);
+ if (wret)
+ ret = wret;
+ } else {
+ memcpy(parent->keys + pslot + 1, right->keys,
+ sizeof(struct key));
+ }
+ }
+ if (mid->header.nritems == 0) {
+ u64 blocknr = mid_buf->blocknr;
+ tree_block_release(root, mid_buf);
+ mid_buf = NULL;
+ mid = NULL;
+ wret = del_ptr(root, path, level + 1, pslot);
+ if (wret)
+ ret = wret;
+ wret = free_extent(root, blocknr, 1);
+ if (wret)
+ ret = wret;
+ } else
+ memcpy(parent->keys + pslot, mid->keys, sizeof(struct key));
+
+ if (left_buf) {
+ if (left->header.nritems >= orig_slot) {
+ left_buf->count++; // released below
+ path->nodes[level] = left_buf;
+ path->slots[level + 1] -= 1;
+ path->slots[level] = orig_slot;
+ if (mid_buf)
+ tree_block_release(root, mid_buf);
+ } else {
+ orig_slot -= left->header.nritems;
+ path->slots[level] = orig_slot;
+ }
+ }
+
+ if (right_buf)
+ tree_block_release(root, right_buf);
+ if (left_buf)
+ tree_block_release(root, left_buf);
+
+ return ret;
+}
+
/*
* 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
@@ -208,12 +339,14 @@
int search_slot(struct ctree_root *root, struct key *key,
struct ctree_path *p, int ins_len)
{
- struct tree_buffer *b = root->node;
+ struct tree_buffer *b;
struct node *c;
int slot;
int ret;
int level;
+again:
+ b = root->node;
b->count++;
while (b) {
c = &b->node;
@@ -236,9 +369,17 @@
b = p->nodes[level];
c = &b->node;
slot = p->slots[level];
+ } else if (ins_len < 0) {
+ int sret = balance_level(root, p, level);
+ if (sret)
+ return sret;
+ b = p->nodes[level];
+ if (!b)
+ goto again;
+ c = &b->node;
+ slot = p->slots[level];
}
b = read_tree_block(root, c->blockptrs[slot]);
- continue;
} else {
struct leaf *l = (struct leaf *)c;
p->slots[level] = slot;
@@ -249,9 +390,11 @@
if (sret)
return sret;
}
+ BUG_ON(root->node->count == 1);
return ret;
}
}
+ BUG_ON(root->node->count == 1);
return 1;
}
@@ -301,161 +444,47 @@
* returns 0 if some ptrs were pushed left, < 0 if there was some horrible
* error, and > 0 if there was no room in the left hand block.
*/
-static int push_node_left(struct ctree_root *root, struct ctree_path *path,
- int level)
+static int push_node_left(struct ctree_root *root, struct tree_buffer *dst_buf,
+ struct tree_buffer *src_buf)
{
- int slot;
- struct node *left;
- struct node *right;
+ struct node *src = &src_buf->node;
+ struct node *dst = &dst_buf->node;
int push_items = 0;
- int left_nritems;
- int right_nritems;
- struct tree_buffer *t;
- struct tree_buffer *right_buf;
+ int src_nritems;
+ int dst_nritems;
int ret = 0;
int wret;
- if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
- return 1;
- slot = path->slots[level + 1];
- if (slot == 0)
- return 1;
-
- t = read_tree_block(root,
- path->nodes[level + 1]->node.blockptrs[slot - 1]);
- left = &t->node;
- right_buf = path->nodes[level];
- right = &right_buf->node;
- left_nritems = left->header.nritems;
- right_nritems = right->header.nritems;
- push_items = NODEPTRS_PER_BLOCK - (left_nritems + 1);
- if (push_items <= 0) {
- tree_block_release(root, t);
- return 1;
- }
-
- if (right_nritems < push_items)
- push_items = right_nritems;
- memcpy(left->keys + left_nritems, right->keys,
- push_items * sizeof(struct key));
- memcpy(left->blockptrs + left_nritems, right->blockptrs,
- push_items * sizeof(u64));
- memmove(right->keys, right->keys + push_items,
- (right_nritems - push_items) * sizeof(struct key));
- memmove(right->blockptrs, right->blockptrs + push_items,
- (right_nritems - push_items) * sizeof(u64));
- right->header.nritems -= push_items;
- left->header.nritems += push_items;
-
- /* adjust the pointers going up the tree */
- wret = fixup_low_keys(root, path, right->keys, level + 1);
- if (wret < 0)
- ret = wret;
-
- wret = write_tree_block(root, t);
- if (wret < 0)
- ret = wret;
-
- wret = write_tree_block(root, right_buf);
- if (wret < 0)
- ret = wret;
-
- /* then fixup the leaf pointer in the path */
- if (path->slots[level] < push_items) {
- path->slots[level] += left_nritems;
- tree_block_release(root, path->nodes[level]);
- path->nodes[level] = t;
- path->slots[level + 1] -= 1;
- } else {
- path->slots[level] -= push_items;
- tree_block_release(root, t);
- }
- return ret;
-}
-
-/*
- * try to push data from one node into the next node right in the
- * tree. The src node is found at specified level in the path.
- * If some bytes were pushed, return 0, otherwise return 1.
- *
- * Lower nodes/leaves in the path are not touched, higher nodes may
- * be modified to reflect the push.
- *
- * The path is altered to reflect the push.
- *
- * returns 0 if some ptrs were pushed, < 0 if there was some horrible
- * error, and > 0 if there was no room in the right hand block.
- */
-static int push_node_right(struct ctree_root *root, struct ctree_path *path,
- int level)
-{
- int slot;
- struct tree_buffer *t;
- struct tree_buffer *src_buffer;
- struct node *dst;
- struct node *src;
- int push_items = 0;
- int dst_nritems;
- int src_nritems;
-
- /* can't push from the root */
- if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
- return 1;
-
- /* only try to push inside the node higher up */
- slot = path->slots[level + 1];
- if (slot == NODEPTRS_PER_BLOCK - 1)
- return 1;
-
- if (slot >= path->nodes[level + 1]->node.header.nritems -1)
- return 1;
-
- t = read_tree_block(root,
- path->nodes[level + 1]->node.blockptrs[slot + 1]);
- dst = &t->node;
- src_buffer = path->nodes[level];
- src = &src_buffer->node;
- dst_nritems = dst->header.nritems;
src_nritems = src->header.nritems;
- push_items = NODEPTRS_PER_BLOCK - (dst_nritems + 1);
+ dst_nritems = dst->header.nritems;
+ push_items = NODEPTRS_PER_BLOCK - dst_nritems;
if (push_items <= 0) {
- tree_block_release(root, t);
return 1;
}
if (src_nritems < push_items)
- push_items = src_nritems;
- memmove(dst->keys + push_items, dst->keys,
- dst_nritems * sizeof(struct key));
- memcpy(dst->keys, src->keys + src_nritems - push_items,
+ push_items =src_nritems;
+ memcpy(dst->keys + dst_nritems, src->keys,
push_items * sizeof(struct key));
-
- memmove(dst->blockptrs + push_items, dst->blockptrs,
- dst_nritems * sizeof(u64));
- memcpy(dst->blockptrs, src->blockptrs + src_nritems - push_items,
+ memcpy(dst->blockptrs + dst_nritems, src->blockptrs,
push_items * sizeof(u64));
-
+ if (push_items < src_nritems) {
+ memmove(src->keys, src->keys + push_items,
+ (src_nritems - push_items) * sizeof(struct key));
+ memmove(src->blockptrs, src->blockptrs + push_items,
+ (src_nritems - push_items) * sizeof(u64));
+ }
src->header.nritems -= push_items;
dst->header.nritems += push_items;
- /* adjust the pointers going up the tree */
- memcpy(path->nodes[level + 1]->node.keys + path->slots[level + 1] + 1,
- dst->keys, sizeof(struct key));
+ wret = write_tree_block(root, src_buf);
+ if (wret < 0)
+ ret = wret;
- write_tree_block(root, path->nodes[level + 1]);
- write_tree_block(root, t);
- write_tree_block(root, src_buffer);
-
- /* then fixup the pointers in the path */
- if (path->slots[level] >= src->header.nritems) {
- path->slots[level] -= src->header.nritems;
- tree_block_release(root, path->nodes[level]);
- path->nodes[level] = t;
- path->slots[level + 1] += 1;
- } else {
- tree_block_release(root, t);
- }
- return 0;
+ wret = write_tree_block(root, dst_buf);
+ if (wret < 0)
+ ret = wret;
+ return ret;
}
/*
@@ -558,16 +587,6 @@
int ret;
int wret;
- ret = push_node_left(root, path, level);
- if (!ret)
- return 0;
- if (ret < 0)
- return ret;
- ret = push_node_right(root, path, level);
- if (!ret)
- return 0;
- if (ret < 0)
- return ret;
t = path->nodes[level];
c = &t->node;
if (t == root->node) {
@@ -1011,6 +1030,7 @@
if (leaf_free_space(leaf) < 0)
BUG();
+ check_leaf(&path, 0);
release_path(root, &path);
return ret;
}
@@ -1022,77 +1042,38 @@
* continuing all the way the root if required. The root is converted into
* a leaf if all the nodes are emptied.
*/
-static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
+static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level,
+ int slot)
{
- int slot;
- struct tree_buffer *t;
struct node *node;
+ struct tree_buffer *parent = path->nodes[level];
int nritems;
- u64 blocknr;
- int wret;
int ret = 0;
+ int wret;
- while(1) {
- t = path->nodes[level];
- if (!t)
- break;
- node = &t->node;
- slot = path->slots[level];
- nritems = node->header.nritems;
+ node = &parent->node;
+ nritems = node->header.nritems;
- if (slot != nritems -1) {
- memmove(node->keys + slot, node->keys + slot + 1,
- sizeof(struct key) * (nritems - slot - 1));
- memmove(node->blockptrs + slot,
- node->blockptrs + slot + 1,
- sizeof(u64) * (nritems - slot - 1));
- }
- node->header.nritems--;
- blocknr = t->blocknr;
- write_tree_block(root, t);
- if (node->header.nritems != 0) {
- int tslot;
- if (slot == 0) {
- wret = fixup_low_keys(root, path,
- node->keys,
- level + 1);
- if (wret)
- ret = wret;
- }
- tslot = path->slots[level + 1];
- t->count++;
- wret = push_node_left(root, path, level);
- if (wret < 0) {
- ret = wret;
- break;
- }
- if (node->header.nritems != 0) {
- wret = push_node_right(root, path, level);
- if (wret < 0) {
- ret = wret;
- break;
- }
- }
- path->slots[level + 1] = tslot;
- if (node->header.nritems != 0) {
- tree_block_release(root, t);
- break;
- }
- tree_block_release(root, t);
- }
- if (t == root->node) {
- /* just turn the root into a leaf and break */
- root->node->node.header.flags = node_level(0);
- write_tree_block(root, t);
- break;
- }
- level++;
- wret = free_extent(root, blocknr, 1);
+ if (slot != nritems -1) {
+ memmove(node->keys + slot, node->keys + slot + 1,
+ sizeof(struct key) * (nritems - slot - 1));
+ memmove(node->blockptrs + slot,
+ node->blockptrs + slot + 1,
+ sizeof(u64) * (nritems - slot - 1));
+ }
+ node->header.nritems--;
+ if (node->header.nritems == 0 && parent == root->node) {
+ BUG_ON(node_level(root->node->node.header.flags) != 1);
+ /* just turn the root into a leaf and break */
+ root->node->node.header.flags = node_level(0);
+ } else if (slot == 0) {
+ wret = fixup_low_keys(root, path, node->keys, level + 1);
if (wret)
ret = wret;
- if (!path->nodes[level])
- BUG();
}
+ wret = write_tree_block(root, parent);
+ if (wret)
+ ret = wret;
return ret;
}
@@ -1135,7 +1116,7 @@
leaf->header.flags = node_level(0);
write_tree_block(root, leaf_buf);
} else {
- wret = del_ptr(root, path, 1);
+ wret = del_ptr(root, path, 1, path->slots[1]);
if (wret)
ret = wret;
wret = free_extent(root, leaf_buf->blocknr, 1);
@@ -1172,8 +1153,7 @@
}
if (leaf->header.nritems == 0) {
u64 blocknr = leaf_buf->blocknr;
- path->slots[1] = slot;
- wret = del_ptr(root, path, 1);
+ wret = del_ptr(root, path, 1, slot);
if (wret)
ret = wret;
tree_block_release(root, leaf_buf);