From 80ea96b1f3bd2431e0d71c9df6ab45c3de0c5840 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Fri, 1 Feb 2008 14:51:59 -0500 Subject: Btrfs: Add a lookup cache to the extent state tree Signed-off-by: Chris Mason diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 624aabc..5f2fbf2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -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) { diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index 6fd5e2c..160da3f 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -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 { -- cgit v0.10.2