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Btrfs: add del_ptr and insert_ptr modifications to the tree mod log
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Record all relevant modifications to block pointers in the tree mod log so
that we can rewind them later on for backref walking.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
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Jan Schmidt committed May 30, 2012
1 parent f230475 commit f3ea38d
Showing 1 changed file with 32 additions and 10 deletions.
42 changes: 32 additions & 10 deletions fs/btrfs/ctree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,8 @@ static int balance_node_right(struct btrfs_trans_handle *trans,
struct extent_buffer *dst_buf,
struct extent_buffer *src_buf);
static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot);
struct btrfs_path *path, int level, int slot,
int tree_mod_log);
static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
struct extent_buffer *eb);
struct extent_buffer *read_old_tree_block(struct btrfs_root *root, u64 bytenr,
Expand Down Expand Up @@ -1465,7 +1466,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
if (btrfs_header_nritems(right) == 0) {
clean_tree_block(trans, root, right);
btrfs_tree_unlock(right);
del_ptr(trans, root, path, level + 1, pslot + 1);
del_ptr(trans, root, path, level + 1, pslot + 1, 1);
root_sub_used(root, right->len);
btrfs_free_tree_block(trans, root, right, 0, 1);
free_extent_buffer_stale(right);
Expand Down Expand Up @@ -1509,7 +1510,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
if (btrfs_header_nritems(mid) == 0) {
clean_tree_block(trans, root, mid);
btrfs_tree_unlock(mid);
del_ptr(trans, root, path, level + 1, pslot);
del_ptr(trans, root, path, level + 1, pslot, 1);
root_sub_used(root, mid->len);
btrfs_free_tree_block(trans, root, mid, 0, 1);
free_extent_buffer_stale(mid);
Expand Down Expand Up @@ -2626,10 +2627,11 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
static void insert_ptr(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_disk_key *key, u64 bytenr,
int slot, int level)
int slot, int level, int tree_mod_log)
{
struct extent_buffer *lower;
int nritems;
int ret;

BUG_ON(!path->nodes[level]);
btrfs_assert_tree_locked(path->nodes[level]);
Expand All @@ -2638,11 +2640,19 @@ static void insert_ptr(struct btrfs_trans_handle *trans,
BUG_ON(slot > nritems);
BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(root));
if (slot != nritems) {
if (tree_mod_log && level)
tree_mod_log_eb_move(root->fs_info, lower, slot + 1,
slot, nritems - slot);
memmove_extent_buffer(lower,
btrfs_node_key_ptr_offset(slot + 1),
btrfs_node_key_ptr_offset(slot),
(nritems - slot) * sizeof(struct btrfs_key_ptr));
}
if (tree_mod_log && level) {
ret = tree_mod_log_insert_key(root->fs_info, lower, slot,
MOD_LOG_KEY_ADD);
BUG_ON(ret < 0);
}
btrfs_set_node_key(lower, key, slot);
btrfs_set_node_blockptr(lower, slot, bytenr);
WARN_ON(trans->transid == 0);
Expand Down Expand Up @@ -2726,7 +2736,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
btrfs_mark_buffer_dirty(split);

insert_ptr(trans, root, path, &disk_key, split->start,
path->slots[level + 1] + 1, level + 1);
path->slots[level + 1] + 1, level + 1, 1);

if (path->slots[level] >= mid) {
path->slots[level] -= mid;
Expand Down Expand Up @@ -3263,7 +3273,7 @@ static noinline void copy_for_split(struct btrfs_trans_handle *trans,
btrfs_set_header_nritems(l, mid);
btrfs_item_key(right, &disk_key, 0);
insert_ptr(trans, root, path, &disk_key, right->start,
path->slots[1] + 1, 1);
path->slots[1] + 1, 1, 0);

btrfs_mark_buffer_dirty(right);
btrfs_mark_buffer_dirty(l);
Expand Down Expand Up @@ -3470,7 +3480,7 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
if (mid <= slot) {
btrfs_set_header_nritems(right, 0);
insert_ptr(trans, root, path, &disk_key, right->start,
path->slots[1] + 1, 1);
path->slots[1] + 1, 1, 0);
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
Expand All @@ -3479,7 +3489,7 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
} else {
btrfs_set_header_nritems(right, 0);
insert_ptr(trans, root, path, &disk_key, right->start,
path->slots[1], 1);
path->slots[1], 1, 0);
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
Expand Down Expand Up @@ -4191,19 +4201,31 @@ int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
* empty a node.
*/
static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot)
struct btrfs_path *path, int level, int slot,
int tree_mod_log)
{
struct extent_buffer *parent = path->nodes[level];
u32 nritems;
int ret;

nritems = btrfs_header_nritems(parent);
if (slot != nritems - 1) {
if (tree_mod_log && level)
tree_mod_log_eb_move(root->fs_info, parent, slot,
slot + 1, nritems - slot - 1);
memmove_extent_buffer(parent,
btrfs_node_key_ptr_offset(slot),
btrfs_node_key_ptr_offset(slot + 1),
sizeof(struct btrfs_key_ptr) *
(nritems - slot - 1));
}

if (tree_mod_log && level) {
ret = tree_mod_log_insert_key(root->fs_info, parent, slot,
MOD_LOG_KEY_REMOVE);
BUG_ON(ret < 0);
}

nritems--;
btrfs_set_header_nritems(parent, nritems);
if (nritems == 0 && parent == root->node) {
Expand Down Expand Up @@ -4235,7 +4257,7 @@ static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
struct extent_buffer *leaf)
{
WARN_ON(btrfs_header_generation(leaf) != trans->transid);
del_ptr(trans, root, path, 1, path->slots[1]);
del_ptr(trans, root, path, 1, path->slots[1], 1);

/*
* btrfs_free_extent is expensive, we want to make sure we
Expand Down

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