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Btrfs: Add a lookup cache to the extent state tree

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2008-02-01 14:51:59 -05:00
parent 4529ba495c
commit 80ea96b1f3
2 changed files with 41 additions and 17 deletions
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57
fs/btrfs/extent_io.c
View File

@ -90,6 +90,7 @@ void extent_io_tree_init(struct extent_io_tree *tree,
tree->mapping = mapping;
INIT_LIST_HEAD(&tree->buffer_lru);
tree->lru_size = 0;
tree->last = NULL;
}
EXPORT_SYMBOL(extent_io_tree_init);
@ -158,16 +159,23 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
return NULL;
}
static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
struct rb_node **prev_ret,
struct rb_node **next_ret)
{
struct rb_root *root = &tree->state;
struct rb_node * n = root->rb_node;
struct rb_node *prev = NULL;
struct rb_node *orig_prev = NULL;
struct tree_entry *entry;
struct tree_entry *prev_entry = NULL;
if (tree->last) {
struct extent_state *state;
state = tree->last;
if (state->start <= offset && offset <= state->end)
return &tree->last->rb_node;
}
while(n) {
entry = rb_entry(n, struct tree_entry, rb_node);
prev = n;
@ -177,8 +185,10 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
n = n->rb_left;
else if (offset > entry->end)
n = n->rb_right;
else
else {
tree->last = rb_entry(n, struct extent_state, rb_node);
return n;
}
}
if (prev_ret) {
@ -202,14 +212,20 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
return NULL;
}
static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
static inline struct rb_node *tree_search(struct extent_io_tree *tree,
u64 offset)
{
struct rb_node *prev = NULL;
struct rb_node *ret;
ret = __tree_search(root, offset, &prev, NULL);
if (!ret)
ret = __etree_search(tree, offset, &prev, NULL);
if (!ret) {
if (prev) {
tree->last = rb_entry(prev, struct extent_state,
rb_node);
}
return prev;
}
return ret;
}
@ -238,6 +254,8 @@ static int merge_state(struct extent_io_tree *tree,
other->state == state->state) {
state->start = other->start;
other->tree = NULL;
if (tree->last == other)
tree->last = NULL;
rb_erase(&other->rb_node, &tree->state);
free_extent_state(other);
}
@ -249,6 +267,8 @@ static int merge_state(struct extent_io_tree *tree,
other->state == state->state) {
other->start = state->start;
state->tree = NULL;
if (tree->last == state)
tree->last = NULL;
rb_erase(&state->rb_node, &tree->state);
free_extent_state(state);
}
@ -311,6 +331,7 @@ static int insert_state(struct extent_io_tree *tree,
return -EEXIST;
}
state->tree = tree;
tree->last = state;
merge_state(tree, state);
return 0;
}
@ -375,6 +396,8 @@ static int clear_state_bit(struct extent_io_tree *tree,
wake_up(&state->wq);
if (delete || state->state == 0) {
if (state->tree) {
if (tree->last == state)
tree->last = NULL;
rb_erase(&state->rb_node, &tree->state);
state->tree = NULL;
free_extent_state(state);
@ -422,7 +445,7 @@ again:
* this search will find the extents that end after
* our range starts
*/
node = tree_search(&tree->state, start);
node = tree_search(tree, start);
if (!node)
goto out;
state = rb_entry(node, struct extent_state, rb_node);
@ -533,7 +556,7 @@ again:
* this search will find all the extents that end after
* our range starts
*/
node = tree_search(&tree->state, start);
node = tree_search(tree, start);
if (!node)
break;
@ -612,7 +635,7 @@ again:
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(&tree->state, start);
node = tree_search(tree, start);
if (!node) {
err = insert_state(tree, prealloc, start, end, bits);
prealloc = NULL;
@ -915,7 +938,7 @@ int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(&tree->state, start);
node = tree_search(tree, start);
if (!node || IS_ERR(node)) {
goto out;
}
@ -953,7 +976,7 @@ u64 find_lock_delalloc_range(struct extent_io_tree *tree,
* our range starts.
*/
search_again:
node = tree_search(&tree->state, cur_start);
node = tree_search(tree, cur_start);
if (!node || IS_ERR(node)) {
*end = (u64)-1;
goto out;
@ -1041,7 +1064,7 @@ u64 count_range_bits(struct extent_io_tree *tree,
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(&tree->state, cur_start);
node = tree_search(tree, cur_start);
if (!node || IS_ERR(node)) {
goto out;
}
@ -1142,7 +1165,7 @@ int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(&tree->state, start);
node = tree_search(tree, start);
if (!node || IS_ERR(node)) {
ret = -ENOENT;
goto out;
@ -1169,7 +1192,7 @@ int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(&tree->state, start);
node = tree_search(tree, start);
if (!node || IS_ERR(node)) {
ret = -ENOENT;
goto out;
@ -1200,7 +1223,7 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long flags;
spin_lock_irqsave(&tree->lock, flags);
node = tree_search(&tree->state, start);
node = tree_search(tree, start);
while (node && start <= end) {
state = rb_entry(node, struct extent_state, rb_node);
@ -1348,7 +1371,7 @@ static int end_bio_extent_writepage(struct bio *bio,
spin_lock_irqsave(&tree->lock, flags);
if (!state || state->end != end) {
state = NULL;
node = __tree_search(&tree->state, start, NULL, NULL);
node = __etree_search(tree, start, NULL, NULL);
if (node) {
state = rb_entry(node, struct extent_state,
rb_node);
@ -1468,7 +1491,7 @@ static int end_bio_extent_readpage(struct bio *bio,
spin_lock_irqsave(&tree->lock, flags);
if (!state || state->end != end) {
state = NULL;
node = __tree_search(&tree->state, start, NULL, NULL);
node = __etree_search(tree, start, NULL, NULL);
if (node) {
state = rb_entry(node, struct extent_state,
rb_node);
@ -1631,7 +1654,7 @@ static int submit_one_bio(int rw, struct bio *bio)
end = start + bvec->bv_len - 1;
spin_lock_irq(&tree->lock);
node = __tree_search(&tree->state, start, NULL, NULL);
node = __etree_search(tree, start, NULL, NULL);
BUG_ON(!node);
state = rb_entry(node, struct extent_state, rb_node);
while(state->end < end) {

1
fs/btrfs/extent_io.h
View File

@ -48,6 +48,7 @@ struct extent_io_tree {
spinlock_t lru_lock;
struct list_head buffer_lru;
int lru_size;
struct extent_state *last;
};
struct extent_state {