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Btrfs: Fixup reference counting on cows

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2007-03-06 20:08:01 -05:00
committed by David Woodhouse
parent 02217ed299
commit a28ec19775
9 changed files with 274 additions and 134 deletions
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305
fs/btrfs/extent-tree.c
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@ -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 @@ static int inc_block_ref(struct ctree_root *root, u64 blocknr)
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 @@ int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf)
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 @@ int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf)
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 @@ check_pending:
*/
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 @@ check_pending:
(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;
}
@ -225,51 +360,6 @@ error:
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.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
@ -296,7 +386,7 @@ int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
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 @@ int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
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 @@ struct tree_buffer *alloc_free_block(struct ctree_root *root)
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;
}