Btrfs: Fixup reference counting on cows
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 25d9cd1..0723b7f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -13,7 +13,8 @@
* other allocations are done. The pending tag is also used in the same
* manner for deletes.
*/
-#define CTREE_EXTENT_PENDING 0
+#define CTREE_EXTENT_PENDING_ADD 0
+#define CTREE_EXTENT_PENDING_DEL 1
static int inc_block_ref(struct ctree_root *root, u64 blocknr)
{
@@ -27,20 +28,51 @@
key.flags = 0;
key.offset = 1;
ret = search_slot(root->extent_root, &key, &path, 0, 1);
+ if (ret != 0)
+ BUG();
BUG_ON(ret != 0);
l = &path.nodes[0]->leaf;
item = (struct extent_item *)(l->data +
l->items[path.slots[0]].offset);
item->refs++;
+
BUG_ON(list_empty(&path.nodes[0]->dirty));
release_path(root->extent_root, &path);
return 0;
}
+static int lookup_block_ref(struct ctree_root *root, u64 blocknr, int *refs)
+{
+ struct ctree_path path;
+ int ret;
+ struct key key;
+ struct leaf *l;
+ struct extent_item *item;
+ init_path(&path);
+ key.objectid = blocknr;
+ key.flags = 0;
+ key.offset = 1;
+ ret = search_slot(root->extent_root, &key, &path, 0, 0);
+ if (ret != 0)
+ BUG();
+ l = &path.nodes[0]->leaf;
+ item = (struct extent_item *)(l->data +
+ l->items[path.slots[0]].offset);
+ *refs = item->refs;
+ release_path(root->extent_root, &path);
+ return 0;
+}
+
int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf)
{
u64 blocknr;
int i;
+
+ if (root == root->extent_root)
+ return 0;
+ if (is_leaf(buf->node.header.flags))
+ return 0;
+
for (i = 0; i < buf->node.header.nritems; i++) {
blocknr = buf->node.blockptrs[i];
inc_block_ref(root, blocknr);
@@ -48,6 +80,113 @@
return 0;
}
+int btrfs_finish_extent_commit(struct ctree_root *root)
+{
+ struct ctree_root *extent_root = root->extent_root;
+ unsigned long gang[8];
+ int ret;
+ int i;
+
+ while(1) {
+ ret = radix_tree_gang_lookup(&extent_root->pinned_radix,
+ (void **)gang, 0,
+ ARRAY_SIZE(gang));
+ if (!ret)
+ break;
+ for (i = 0; i < ret; i++)
+ radix_tree_delete(&extent_root->pinned_radix, gang[i]);
+ }
+ return 0;
+}
+
+/*
+ * remove an extent from the root, returns 0 on success
+ */
+int __free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
+{
+ struct ctree_path path;
+ struct key key;
+ struct ctree_root *extent_root = root->extent_root;
+ int ret;
+ struct item *item;
+ struct extent_item *ei;
+ key.objectid = blocknr;
+ key.flags = 0;
+ key.offset = num_blocks;
+
+ init_path(&path);
+ ret = search_slot(extent_root, &key, &path, -1, 1);
+ if (ret) {
+ printf("failed to find %Lu\n", key.objectid);
+ print_tree(extent_root, extent_root->node);
+ printf("failed to find %Lu\n", key.objectid);
+ BUG();
+ }
+ item = path.nodes[0]->leaf.items + path.slots[0];
+ ei = (struct extent_item *)(path.nodes[0]->leaf.data + item->offset);
+ BUG_ON(ei->refs == 0);
+ ei->refs--;
+ if (ei->refs == 0) {
+ if (root == extent_root) {
+ int err;
+ radix_tree_preload(GFP_KERNEL);
+ err = radix_tree_insert(&extent_root->pinned_radix,
+ blocknr, (void *)blocknr);
+ BUG_ON(err);
+ radix_tree_preload_end();
+ }
+ ret = del_item(extent_root, &path);
+ if (ret)
+ BUG();
+ }
+ release_path(extent_root, &path);
+ return ret;
+}
+
+/*
+ * insert all of the pending extents reserved during the original
+ * allocation. (CTREE_EXTENT_PENDING). Returns zero if it all worked out
+ */
+static int insert_pending_extents(struct ctree_root *extent_root)
+{
+ int ret;
+ struct key key;
+ struct extent_item item;
+ struct tree_buffer *gang[4];
+ int i;
+
+ // FIXME -ENOSPC
+ item.owner = extent_root->node->node.header.parentid;
+ item.refs = 1;
+ while(1) {
+ ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
+ (void **)gang, 0,
+ ARRAY_SIZE(gang),
+ CTREE_EXTENT_PENDING_ADD);
+ if (!ret)
+ break;
+ for (i = 0; i < ret; i++) {
+ key.objectid = gang[i]->blocknr;
+ key.flags = 0;
+ key.offset = 1;
+ ret = insert_item(extent_root, &key, &item,
+ sizeof(item));
+ if (ret) {
+ printf("%Lu already in tree\n", key.objectid);
+ print_tree(extent_root, extent_root->node);
+ BUG();
+ // FIXME undo it and return sane
+ return ret;
+ }
+ radix_tree_tag_clear(&extent_root->cache_radix,
+ gang[i]->blocknr,
+ CTREE_EXTENT_PENDING_ADD);
+ tree_block_release(extent_root, gang[i]);
+ }
+ }
+ return 0;
+}
+
/*
* find all the blocks marked as pending in the radix tree and remove
* them from the extent map
@@ -55,78 +194,73 @@
static int del_pending_extents(struct ctree_root *extent_root)
{
int ret;
- struct key key;
struct tree_buffer *gang[4];
int i;
- struct ctree_path path;
while(1) {
ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
(void **)gang, 0,
ARRAY_SIZE(gang),
- CTREE_EXTENT_PENDING);
+ CTREE_EXTENT_PENDING_DEL);
if (!ret)
break;
for (i = 0; i < ret; i++) {
- key.objectid = gang[i]->blocknr;
- key.flags = 0;
- key.offset = 1;
- init_path(&path);
- ret = search_slot(extent_root, &key, &path, -1, 1);
- if (ret) {
- print_tree(extent_root, extent_root->node);
- printf("unable to find %Lu\n", key.objectid);
- BUG();
- // FIXME undo it and return sane
- return ret;
- }
- ret = del_item(extent_root, &path);
- if (ret) {
- BUG();
- return ret;
- }
- release_path(extent_root, &path);
+ ret = __free_extent(extent_root, gang[i]->blocknr, 1);
radix_tree_tag_clear(&extent_root->cache_radix,
gang[i]->blocknr,
- CTREE_EXTENT_PENDING);
+ CTREE_EXTENT_PENDING_DEL);
tree_block_release(extent_root, gang[i]);
}
}
return 0;
}
+static int run_pending(struct ctree_root *extent_root)
+{
+ while(radix_tree_tagged(&extent_root->cache_radix,
+ CTREE_EXTENT_PENDING_DEL) ||
+ radix_tree_tagged(&extent_root->cache_radix,
+ CTREE_EXTENT_PENDING_ADD)) {
+ insert_pending_extents(extent_root);
+ del_pending_extents(extent_root);
+ }
+ return 0;
+}
+
+
/*
* remove an extent from the root, returns 0 on success
*/
int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
{
- struct ctree_path path;
struct key key;
struct ctree_root *extent_root = root->extent_root;
struct tree_buffer *t;
int pending_ret;
int ret;
+
+ if (root == extent_root) {
+ t = find_tree_block(root, blocknr);
+ if (radix_tree_tag_get(&root->cache_radix, blocknr,
+ CTREE_EXTENT_PENDING_ADD)) {
+ radix_tree_tag_clear(&root->cache_radix,
+ blocknr,
+ CTREE_EXTENT_PENDING_ADD);
+ /* once for us */
+ tree_block_release(root, t);
+ /* once for the pending add */
+ tree_block_release(root, t);
+ } else {
+ radix_tree_tag_set(&root->cache_radix, blocknr,
+ CTREE_EXTENT_PENDING_DEL);
+ }
+ return 0;
+ }
key.objectid = blocknr;
key.flags = 0;
key.offset = num_blocks;
- if (root == extent_root) {
- t = read_tree_block(root, key.objectid);
- radix_tree_tag_set(&root->cache_radix, key.objectid,
- CTREE_EXTENT_PENDING);
- return 0;
- }
- init_path(&path);
- ret = search_slot(extent_root, &key, &path, -1, 1);
- if (ret) {
- print_tree(extent_root, extent_root->node);
- printf("failed to find %Lu\n", key.objectid);
- BUG();
- }
- ret = del_item(extent_root, &path);
- if (ret)
- BUG();
- release_path(extent_root, &path);
- pending_ret = del_pending_extents(root->extent_root);
+ ret = __free_extent(root, blocknr, num_blocks);
+ pending_ret = run_pending(root->extent_root);
return ret ? ret : pending_ret;
}
@@ -203,7 +337,7 @@
*/
release_path(root, &path);
BUG_ON(ins->objectid < search_start);
- if (orig_root->extent_root == orig_root) {
+ if (1 || orig_root->extent_root == orig_root) {
BUG_ON(num_blocks != 1);
if ((root->current_insert.objectid <= ins->objectid &&
root->current_insert.objectid +
@@ -211,8 +345,9 @@
(root->current_insert.objectid > ins->objectid &&
root->current_insert.objectid <= ins->objectid +
ins->offset) ||
+ radix_tree_lookup(&root->pinned_radix, ins->objectid) ||
radix_tree_tag_get(&root->cache_radix, ins->objectid,
- CTREE_EXTENT_PENDING)) {
+ CTREE_EXTENT_PENDING_ADD)) {
search_start = ins->objectid + 1;
goto check_failed;
}
@@ -226,51 +361,6 @@
}
/*
- * insert all of the pending extents reserved during the original
- * allocation. (CTREE_EXTENT_PENDING). Returns zero if it all worked out
- */
-static int insert_pending_extents(struct ctree_root *extent_root)
-{
- int ret;
- struct key key;
- struct extent_item item;
- struct tree_buffer *gang[4];
- int i;
-
- // FIXME -ENOSPC
- item.refs = 1;
- item.owner = extent_root->node->node.header.parentid;
- while(1) {
- ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
- (void **)gang, 0,
- ARRAY_SIZE(gang),
- CTREE_EXTENT_PENDING);
- if (!ret)
- break;
- for (i = 0; i < ret; i++) {
- key.objectid = gang[i]->blocknr;
- key.flags = 0;
- key.offset = 1;
- ret = insert_item(extent_root, &key, &item,
- sizeof(item));
- if (ret) {
- printf("%Lu already in tree\n", key.objectid);
- print_tree(extent_root, extent_root->node);
- BUG();
- // FIXME undo it and return sane
- return ret;
- }
- radix_tree_tag_clear(&extent_root->cache_radix,
- gang[i]->blocknr,
- CTREE_EXTENT_PENDING);
- printf("%Lu is not pending\n", gang[i]->blocknr);
- tree_block_release(extent_root, gang[i]);
- }
- }
- return 0;
-}
-
-/*
* finds a free extent and does all the dirty work required for allocation
* returns the key for the extent through ins, and a tree buffer for
* the first block of the extent through buf.
@@ -296,7 +386,7 @@
sizeof(extent_item));
memset(&root->extent_root->current_insert, 0,
sizeof(struct key));
- pending_ret = insert_pending_extents(root->extent_root);
+ pending_ret = run_pending(root->extent_root);
if (ret)
return ret;
if (pending_ret)
@@ -309,9 +399,8 @@
BUG_ON(ins->offset != 1);
*buf = find_tree_block(root, ins->objectid);
BUG_ON(!*buf);
- printf("%Lu is pending\n", ins->objectid);
radix_tree_tag_set(&root->cache_radix, ins->objectid,
- CTREE_EXTENT_PENDING);
+ CTREE_EXTENT_PENDING_ADD);
(*buf)->count++;
dirty_tree_block(root, *buf);
return 0;
@@ -331,13 +420,41 @@
ret = alloc_extent(root, 1, 0, (unsigned long)-1,
root->node->node.header.parentid,
&ins, &buf);
-
if (ret) {
BUG();
return NULL;
}
if (root != root->extent_root)
BUG_ON(radix_tree_tag_get(&root->extent_root->cache_radix,
- buf->blocknr, CTREE_EXTENT_PENDING));
+ buf->blocknr,
+ CTREE_EXTENT_PENDING_ADD));
return buf;
}
+
+int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
+{
+ int ret;
+ int level;
+ int refs;
+ u64 blocknr = snap->blocknr;
+
+ level = node_level(snap->node.header.flags);
+ ret = lookup_block_ref(root, snap->blocknr, &refs);
+ BUG_ON(ret);
+ if (refs == 1 && level != 0) {
+ struct node *n = &snap->node;
+ struct tree_buffer *b;
+ int i;
+ for (i = 0; i < n->header.nritems; i++) {
+ b = read_tree_block(root, n->blockptrs[i]);
+ /* FIXME, don't recurse here */
+ ret = btrfs_drop_snapshot(root, b);
+ BUG_ON(ret);
+ tree_block_release(root, b);
+ }
+ }
+ ret = free_extent(root, blocknr, 1);
+ BUG_ON(ret);
+ return 0;
+}
+