diff options
author | Chris Mason <chris.mason@oracle.com> | 2007-02-02 15:18:22 +0100 |
---|---|---|
committer | David Woodhouse <dwmw2@hera.kernel.org> | 2007-02-02 15:18:22 +0100 |
commit | eb60ceac0ebd11e9896ed1ca84fcad71a4b23601 (patch) | |
tree | 70d426737630b713bc18dc5ae8c342651f0f1f44 | |
parent | Btrfs: Faster deletes, add Makefile and kerncompat (diff) | |
download | linux-eb60ceac0ebd11e9896ed1ca84fcad71a4b23601.tar.xz linux-eb60ceac0ebd11e9896ed1ca84fcad71a4b23601.zip |
Btrfs: Add backing store, memory management
Signed-off-by: Chris Mason <chris.mason@oracle.com>
-rw-r--r-- | fs/btrfs/Makefile | 11 | ||||
-rw-r--r-- | fs/btrfs/ctree.c | 432 | ||||
-rw-r--r-- | fs/btrfs/ctree.h | 62 | ||||
-rw-r--r-- | fs/btrfs/disk-io.c | 174 | ||||
-rw-r--r-- | fs/btrfs/disk-io.h | 21 | ||||
-rw-r--r-- | fs/btrfs/kerncompat.h | 1 | ||||
-rw-r--r-- | fs/btrfs/radix-tree.c | 836 | ||||
-rw-r--r-- | fs/btrfs/radix-tree.h | 73 |
8 files changed, 1447 insertions, 163 deletions
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile index 9f84c08baab2..63360212a075 100644 --- a/fs/btrfs/Makefile +++ b/fs/btrfs/Makefile @@ -1,7 +1,12 @@ -ctree: ctree.o - gcc -g -O2 -Wall -o ctree ctree.c +CFLAGS= -g -Wall + +.c.o: + $(CC) $(CFLAGS) -c $< + +ctree: ctree.o disk-io.h ctree.h disk-io.o radix-tree.o radix-tree.h + gcc $(CFLAGS) -o ctree ctree.o disk-io.o radix-tree.o clean: - rm ctree ctree.o + rm ctree *.o diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 4bf5e92584bd..6f0522f21082 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1,68 +1,25 @@ #include <stdio.h> #include <stdlib.h> #include "kerncompat.h" - -#define BLOCKSIZE 4096 - -struct key { - u64 objectid; - u32 flags; - u64 offset; -} __attribute__ ((__packed__)); - -struct header { - u64 fsid[2]; /* FS specific uuid */ - u64 blocknum; - u64 parentid; - u32 csum; - u32 ham; - u16 nritems; - u16 flags; -} __attribute__ ((__packed__)); - -#define NODEPTRS_PER_BLOCK ((BLOCKSIZE - sizeof(struct header)) / \ - (sizeof(struct key) + sizeof(u64))) - -#define LEVEL_BITS 3 -#define MAX_LEVEL (1 << LEVEL_BITS) -#define node_level(f) ((f) & (MAX_LEVEL-1)) -#define is_leaf(f) (node_level(f) == 0) - -struct ctree_root { - struct node *node; -}; - -struct item { - struct key key; - u16 offset; - u16 size; -} __attribute__ ((__packed__)); - -#define LEAF_DATA_SIZE (BLOCKSIZE - sizeof(struct header)) -struct leaf { - struct header header; - union { - struct item items[LEAF_DATA_SIZE/sizeof(struct item)]; - u8 data[BLOCKSIZE-sizeof(struct header)]; - }; -} __attribute__ ((__packed__)); - -struct node { - struct header header; - struct key keys[NODEPTRS_PER_BLOCK]; - u64 blockptrs[NODEPTRS_PER_BLOCK]; -} __attribute__ ((__packed__)); - -struct ctree_path { - struct node *nodes[MAX_LEVEL]; - int slots[MAX_LEVEL]; -}; +#include "radix-tree.h" +#include "ctree.h" +#include "disk-io.h" static inline void init_path(struct ctree_path *p) { memset(p, 0, sizeof(*p)); } +static void release_path(struct ctree_root *root, struct ctree_path *p) +{ + int i; + for (i = 0; i < MAX_LEVEL; i++) { + if (!p->nodes[i]) + break; + tree_block_release(root, p->nodes[i]); + } +} + static inline unsigned int leaf_data_end(struct leaf *leaf) { unsigned int nr = leaf->header.nritems; @@ -135,26 +92,25 @@ int bin_search(struct node *c, struct key *key, int *slot) return -1; } -void *read_block(u64 blocknum) -{ - return (void *)blocknum; -} - int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p) { - struct node *c = root->node; + struct tree_buffer *b = root->node; + struct node *c; + int slot; int ret; int level; - while (c) { + b->count++; + while (b) { + c = &b->node; level = node_level(c->header.flags); - p->nodes[level] = c; + p->nodes[level] = b; ret = bin_search(c, key, &slot); if (!is_leaf(c->header.flags)) { if (ret && slot > 0) slot -= 1; p->slots[level] = slot; - c = read_block(c->blockptrs[slot]); + b = read_tree_block(root, c->blockptrs[slot]); continue; } else { p->slots[level] = slot; @@ -164,17 +120,20 @@ int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p) return -1; } -static void fixup_low_keys(struct ctree_path *path, struct key *key, - int level) +static void fixup_low_keys(struct ctree_root *root, + struct ctree_path *path, struct key *key, + int level) { int i; /* adjust the pointers going up the tree */ for (i = level; i < MAX_LEVEL; i++) { - struct node *t = path->nodes[i]; + struct node *t; int tslot = path->slots[i]; - if (!t) + if (!path->nodes[i]) break; + t = &path->nodes[i]->node; memcpy(t->keys + tslot, key, sizeof(*key)); + write_tree_block(root, path->nodes[i]); if (tslot != 0) break; } @@ -190,27 +149,34 @@ int __insert_ptr(struct ctree_root *root, int nritems; /* need a new root */ if (!path->nodes[level]) { - c = malloc(sizeof(struct node)); + struct tree_buffer *t; + t = alloc_free_block(root); + c = &t->node; memset(c, 0, sizeof(c)); c->header.nritems = 2; c->header.flags = node_level(level); - lower = path->nodes[level-1]; + c->header.blocknr = t->blocknr; + lower = &path->nodes[level-1]->node; if (is_leaf(lower->header.flags)) lower_key = &((struct leaf *)lower)->items[0].key; else lower_key = lower->keys; memcpy(c->keys, lower_key, sizeof(struct key)); memcpy(c->keys + 1, key, sizeof(struct key)); - c->blockptrs[0] = (u64)lower; + c->blockptrs[0] = path->nodes[level-1]->blocknr; c->blockptrs[1] = blocknr; - root->node = c; - path->nodes[level] = c; + /* the path has an extra ref to root->node */ + tree_block_release(root, root->node); + root->node = t; + t->count++; + write_tree_block(root, t); + path->nodes[level] = t; path->slots[level] = 0; if (c->keys[1].objectid == 0) BUG(); return 0; } - lower = path->nodes[level]; + lower = &path->nodes[level]->node; nritems = lower->header.nritems; if (slot > nritems) BUG(); @@ -227,6 +193,7 @@ int __insert_ptr(struct ctree_root *root, lower->header.nritems++; if (lower->keys[1].objectid == 0) BUG(); + write_tree_block(root, path->nodes[level]); return 0; } @@ -238,6 +205,8 @@ int push_node_left(struct ctree_root *root, struct ctree_path *path, int level) int push_items = 0; int left_nritems; int right_nritems; + struct tree_buffer *t; + struct tree_buffer *right_buf; if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0) return 1; @@ -245,13 +214,18 @@ int push_node_left(struct ctree_root *root, struct ctree_path *path, int level) if (slot == 0) return 1; - left = read_block(path->nodes[level + 1]->blockptrs[slot - 1]); - right = path->nodes[level]; + t = read_tree_block(root, + path->nodes[level + 1]->node.blockptrs[slot - 1]); + left = &t->node; + right_buf = path->nodes[level]; + right = &right_buf->node; left_nritems = left->header.nritems; right_nritems = right->header.nritems; push_items = NODEPTRS_PER_BLOCK - (left_nritems + 1); - if (push_items <= 0) + if (push_items <= 0) { + tree_block_release(root, t); return 1; + } if (right_nritems < push_items) push_items = right_nritems; @@ -267,15 +241,20 @@ int push_node_left(struct ctree_root *root, struct ctree_path *path, int level) left->header.nritems += push_items; /* adjust the pointers going up the tree */ - fixup_low_keys(path, right->keys, level + 1); + fixup_low_keys(root, path, right->keys, level + 1); + + write_tree_block(root, t); + write_tree_block(root, right_buf); /* then fixup the leaf pointer in the path */ if (path->slots[level] < push_items) { path->slots[level] += left_nritems; - path->nodes[level] = (struct node*)left; + tree_block_release(root, path->nodes[level]); + path->nodes[level] = t; path->slots[level + 1] -= 1; } else { path->slots[level] -= push_items; + tree_block_release(root, t); } return 0; } @@ -283,6 +262,8 @@ int push_node_left(struct ctree_root *root, struct ctree_path *path, int level) int push_node_right(struct ctree_root *root, struct ctree_path *path, int level) { int slot; + struct tree_buffer *t; + struct tree_buffer *src_buffer; struct node *dst; struct node *src; int push_items = 0; @@ -295,16 +276,21 @@ int push_node_right(struct ctree_root *root, struct ctree_path *path, int level) if (slot == NODEPTRS_PER_BLOCK - 1) return 1; - if (slot >= path->nodes[level + 1]->header.nritems -1) + if (slot >= path->nodes[level + 1]->node.header.nritems -1) return 1; - dst = read_block(path->nodes[level + 1]->blockptrs[slot + 1]); - src = path->nodes[level]; + t = read_tree_block(root, + path->nodes[level + 1]->node.blockptrs[slot + 1]); + dst = &t->node; + src_buffer = path->nodes[level]; + src = &src_buffer->node; dst_nritems = dst->header.nritems; src_nritems = src->header.nritems; push_items = NODEPTRS_PER_BLOCK - (dst_nritems + 1); - if (push_items <= 0) + if (push_items <= 0) { + tree_block_release(root, t); return 1; + } if (src_nritems < push_items) push_items = src_nritems; @@ -322,13 +308,21 @@ int push_node_right(struct ctree_root *root, struct ctree_path *path, int level) dst->header.nritems += push_items; /* adjust the pointers going up the tree */ - memcpy(path->nodes[level + 1]->keys + path->slots[level + 1] + 1, + memcpy(path->nodes[level + 1]->node.keys + path->slots[level + 1] + 1, dst->keys, sizeof(struct key)); + + write_tree_block(root, path->nodes[level + 1]); + write_tree_block(root, t); + write_tree_block(root, src_buffer); + /* then fixup the leaf pointer in the path */ if (path->slots[level] >= src->header.nritems) { path->slots[level] -= src->header.nritems; - path->nodes[level] = (struct node*)dst; + tree_block_release(root, path->nodes[level]); + path->nodes[level] = t; path->slots[level + 1] += 1; + } else { + tree_block_release(root, t); } return 0; } @@ -337,15 +331,18 @@ int insert_ptr(struct ctree_root *root, struct ctree_path *path, struct key *key, u64 blocknr, int level) { - struct node *c = path->nodes[level]; + struct tree_buffer *t = path->nodes[level]; + struct node *c = &path->nodes[level]->node; struct node *b; - struct node *bal[MAX_LEVEL]; + struct tree_buffer *b_buffer; + struct tree_buffer *bal[MAX_LEVEL]; int bal_level = level; int mid; int bal_start = -1; memset(bal, 0, ARRAY_SIZE(bal)); - while(c && c->header.nritems == NODEPTRS_PER_BLOCK) { + while(t && t->node.header.nritems == NODEPTRS_PER_BLOCK) { + c = &t->node; if (push_node_left(root, path, node_level(c->header.flags)) == 0) break; @@ -355,8 +352,10 @@ int insert_ptr(struct ctree_root *root, bal_start = bal_level; if (bal_level == MAX_LEVEL - 1) BUG(); - b = malloc(sizeof(struct node)); + b_buffer = alloc_free_block(root); + b = &b_buffer->node; b->header.flags = c->header.flags; + b->header.blocknr = b_buffer->blocknr; mid = (c->header.nritems + 1) / 2; memcpy(b->keys, c->keys + mid, (c->header.nritems - mid) * sizeof(struct key)); @@ -364,21 +363,28 @@ int insert_ptr(struct ctree_root *root, (c->header.nritems - mid) * sizeof(u64)); b->header.nritems = c->header.nritems - mid; c->header.nritems = mid; - bal[bal_level] = b; + + write_tree_block(root, t); + write_tree_block(root, b_buffer); + + bal[bal_level] = b_buffer; if (bal_level == MAX_LEVEL - 1) break; bal_level += 1; - c = path->nodes[bal_level]; + t = path->nodes[bal_level]; } while(bal_start > 0) { - b = bal[bal_start]; - c = path->nodes[bal_start]; - __insert_ptr(root, path, b->keys, (u64)b, + b_buffer = bal[bal_start]; + c = &path->nodes[bal_start]->node; + __insert_ptr(root, path, b_buffer->node.keys, b_buffer->blocknr, path->slots[bal_start + 1] + 1, bal_start + 1); if (path->slots[bal_start] >= c->header.nritems) { path->slots[bal_start] -= c->header.nritems; - path->nodes[bal_start] = b; + tree_block_release(root, path->nodes[bal_start]); + path->nodes[bal_start] = b_buffer; path->slots[bal_start + 1] += 1; + } else { + tree_block_release(root, b_buffer); } bal_start--; if (!bal[bal_start]) @@ -404,7 +410,9 @@ int leaf_space_used(struct leaf *l, int start, int nr) int push_leaf_left(struct ctree_root *root, struct ctree_path *path, int data_size) { - struct leaf *right = (struct leaf *)path->nodes[0]; + struct tree_buffer *right_buf = path->nodes[0]; + struct leaf *right = &right_buf->leaf; + struct tree_buffer *t; struct leaf *left; int slot; int i; @@ -421,9 +429,11 @@ int push_leaf_left(struct ctree_root *root, struct ctree_path *path, if (!path->nodes[1]) { return 1; } - left = read_block(path->nodes[1]->blockptrs[slot - 1]); + t = read_tree_block(root, path->nodes[1]->node.blockptrs[slot - 1]); + left = &t->leaf; free_space = leaf_free_space(left); if (free_space < data_size + sizeof(struct item)) { + tree_block_release(root, t); return 1; } for (i = 0; i < right->header.nritems; i++) { @@ -436,6 +446,7 @@ int push_leaf_left(struct ctree_root *root, struct ctree_path *path, push_space += item->size + sizeof(*item); } if (push_items == 0) { + tree_block_release(root, t); return 1; } /* push data from right to left */ @@ -446,6 +457,8 @@ int push_leaf_left(struct ctree_root *root, struct ctree_path *path, right->data + right->items[push_items - 1].offset, push_space); old_left_nritems = left->header.nritems; + BUG_ON(old_left_nritems < 0); + for(i = old_left_nritems; i < old_left_nritems + push_items; i++) { left->items[i].offset -= LEAF_DATA_SIZE - left->items[old_left_nritems -1].offset; @@ -460,30 +473,40 @@ int push_leaf_left(struct ctree_root *root, struct ctree_path *path, (right->header.nritems - push_items) * sizeof(struct item)); right->header.nritems -= push_items; push_space = LEAF_DATA_SIZE; + for (i = 0; i < right->header.nritems; i++) { right->items[i].offset = push_space - right->items[i].size; push_space = right->items[i].offset; } - fixup_low_keys(path, &right->items[0].key, 1); + + write_tree_block(root, t); + write_tree_block(root, right_buf); + + fixup_low_keys(root, path, &right->items[0].key, 1); /* then fixup the leaf pointer in the path */ if (path->slots[0] < push_items) { path->slots[0] += old_left_nritems; - path->nodes[0] = (struct node*)left; + tree_block_release(root, path->nodes[0]); + path->nodes[0] = t; path->slots[1] -= 1; } else { + tree_block_release(root, t); path->slots[0] -= push_items; } + BUG_ON(path->slots[0] < 0); return 0; } int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size) { - struct leaf *l = (struct leaf *)path->nodes[0]; - int nritems = l->header.nritems; - int mid = (nritems + 1)/ 2; - int slot = path->slots[0]; + struct tree_buffer *l_buf = path->nodes[0]; + struct leaf *l = &l_buf->leaf; + int nritems; + int mid; + int slot; struct leaf *right; + struct tree_buffer *right_buffer; int space_needed = data_size + sizeof(struct item); int data_copy_size; int rt_data_off; @@ -491,9 +514,19 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size) int ret; if (push_leaf_left(root, path, data_size) == 0) { - return 0; + l_buf = path->nodes[0]; + l = &l_buf->leaf; + if (leaf_free_space(l) >= sizeof(struct item) + data_size) + return 0; } - right = malloc(sizeof(struct leaf)); + slot = path->slots[0]; + nritems = l->header.nritems; + mid = (nritems + 1)/ 2; + + right_buffer = alloc_free_block(root); + BUG_ON(!right_buffer); + BUG_ON(mid == nritems); + right = &right_buffer->leaf; memset(right, 0, sizeof(*right)); if (mid <= slot) { if (leaf_space_used(l, mid, nritems - mid) + space_needed > @@ -505,6 +538,8 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size) BUG(); } right->header.nritems = nritems - mid; + right->header.blocknr = right_buffer->blocknr; + right->header.flags = node_level(0); data_copy_size = l->items[mid].offset + l->items[mid].size - leaf_data_end(l); memcpy(right->items, l->items + mid, @@ -518,12 +553,20 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size) } l->header.nritems = mid; ret = insert_ptr(root, path, &right->items[0].key, - (u64)right, 1); + right_buffer->blocknr, 1); + + write_tree_block(root, right_buffer); + write_tree_block(root, l_buf); + + BUG_ON(path->slots[0] != slot); if (mid <= slot) { - path->nodes[0] = (struct node *)right; + tree_block_release(root, path->nodes[0]); + path->nodes[0] = right_buffer; path->slots[0] -= mid; path->slots[1] += 1; - } + } else + tree_block_release(root, right_buffer); + BUG_ON(path->slots[0] < 0); return ret; } @@ -532,28 +575,48 @@ int insert_item(struct ctree_root *root, struct key *key, { int ret; int slot; + int slot_orig; struct leaf *leaf; + struct tree_buffer *leaf_buf; unsigned int nritems; unsigned int data_end; struct ctree_path path; + if (!root->node) { + struct tree_buffer *t; + t = alloc_free_block(root); + BUG_ON(!t); + t->node.header.nritems = 0; + t->node.header.flags = node_level(0); + t->node.header.blocknr = t->blocknr; + root->node = t; + write_tree_block(root, t); + } init_path(&path); ret = search_slot(root, key, &path); - if (ret == 0) + if (ret == 0) { + release_path(root, &path); return -EEXIST; + } - leaf = (struct leaf *)path.nodes[0]; - if (leaf_free_space(leaf) < sizeof(struct item) + data_size) + slot_orig = path.slots[0]; + leaf_buf = path.nodes[0]; + leaf = &leaf_buf->leaf; + if (leaf_free_space(leaf) < sizeof(struct item) + data_size) { split_leaf(root, &path, data_size); - leaf = (struct leaf *)path.nodes[0]; + leaf_buf = path.nodes[0]; + leaf = &path.nodes[0]->leaf; + } nritems = leaf->header.nritems; data_end = leaf_data_end(leaf); + if (leaf_free_space(leaf) < sizeof(struct item) + data_size) BUG(); slot = path.slots[0]; + BUG_ON(slot < 0); if (slot == 0) - fixup_low_keys(&path, key, 1); + fixup_low_keys(root, &path, key, 1); if (slot != nritems) { int i; unsigned int old_data = leaf->items[slot].offset + @@ -580,21 +643,25 @@ int insert_item(struct ctree_root *root, struct key *key, leaf->items[slot].size = data_size; memcpy(leaf->data + data_end - data_size, data, data_size); leaf->header.nritems += 1; + write_tree_block(root, leaf_buf); if (leaf_free_space(leaf) < 0) BUG(); + release_path(root, &path); return 0; } int del_ptr(struct ctree_root *root, struct ctree_path *path, int level) { int slot; + struct tree_buffer *t; struct node *node; int nritems; while(1) { - node = path->nodes[level]; - if (!node) + t = path->nodes[level]; + if (!t) break; + node = &t->node; slot = path->slots[level]; nritems = node->header.nritems; @@ -606,28 +673,34 @@ int del_ptr(struct ctree_root *root, struct ctree_path *path, int level) sizeof(u64) * (nritems - slot - 1)); } node->header.nritems--; + write_tree_block(root, t); if (node->header.nritems != 0) { int tslot; if (slot == 0) - fixup_low_keys(path, node->keys, level + 1); + fixup_low_keys(root, path, node->keys, + level + 1); tslot = path->slots[level+1]; + t->count++; push_node_left(root, path, level); if (node->header.nritems) { push_node_right(root, path, level); } - if (node->header.nritems) + if (node->header.nritems) { + tree_block_release(root, t); break; + } + tree_block_release(root, t); path->slots[level+1] = tslot; } - if (node == root->node) { - printf("root is now null!\n"); - root->node = NULL; + if (t == root->node) { + /* just turn the root into a leaf and break */ + root->node->node.header.flags = node_level(0); + write_tree_block(root, t); break; } level++; if (!path->nodes[level]) BUG(); - free(node); } return 0; } @@ -636,10 +709,12 @@ int del_item(struct ctree_root *root, struct ctree_path *path) { int slot; struct leaf *leaf; + struct tree_buffer *leaf_buf; int doff; int dsize; - leaf = (struct leaf *)path->nodes[0]; + leaf_buf = path->nodes[0]; + leaf = &leaf_buf->leaf; slot = path->slots[0]; doff = leaf->items[slot].offset; dsize = leaf->items[slot].size; @@ -658,14 +733,15 @@ int del_item(struct ctree_root *root, struct ctree_path *path) } leaf->header.nritems -= 1; if (leaf->header.nritems == 0) { - if (leaf == (struct leaf *)root->node) - root->node = NULL; - else + if (leaf_buf == root->node) { + leaf->header.flags = node_level(0); + write_tree_block(root, leaf_buf); + } else del_ptr(root, path, 1); - free(leaf); } else { if (slot == 0) - fixup_low_keys(path, &leaf->items[0].key, 1); + fixup_low_keys(root, path, &leaf->items[0].key, 1); + write_tree_block(root, leaf_buf); if (leaf_space_used(leaf, 0, leaf->header.nritems) < LEAF_DATA_SIZE / 4) { /* push_leaf_left fixes the path. @@ -673,12 +749,13 @@ int del_item(struct ctree_root *root, struct ctree_path *path) * for possible call to del_ptr below */ slot = path->slots[1]; + leaf_buf->count++; push_leaf_left(root, path, 1); if (leaf->header.nritems == 0) { - free(leaf); path->slots[1] = slot; del_ptr(root, path, 1); } + tree_block_release(root, leaf_buf); } } return 0; @@ -689,7 +766,7 @@ void print_leaf(struct leaf *l) int i; int nr = l->header.nritems; struct item *item; - printf("leaf %p total ptrs %d free space %d\n", l, nr, + printf("leaf %lu total ptrs %d free space %d\n", l->header.blocknr, nr, leaf_free_space(l)); fflush(stdout); for (i = 0 ; i < nr ; i++) { @@ -703,38 +780,45 @@ void print_leaf(struct leaf *l) fflush(stdout); } } -void print_tree(struct node *c) +void print_tree(struct ctree_root *root, struct tree_buffer *t) { int i; int nr; + struct node *c; - if (!c) + if (!t) return; + c = &t->node; nr = c->header.nritems; + if (c->header.blocknr != t->blocknr) + BUG(); if (is_leaf(c->header.flags)) { print_leaf((struct leaf *)c); return; } - printf("node %p level %d total ptrs %d free spc %lu\n", c, + printf("node %lu level %d total ptrs %d free spc %lu\n", t->blocknr, node_level(c->header.flags), c->header.nritems, NODEPTRS_PER_BLOCK - c->header.nritems); fflush(stdout); for (i = 0; i < nr; i++) { - printf("\tkey %d (%lu %u %lu) block %lx\n", + printf("\tkey %d (%lu %u %lu) block %lu\n", i, c->keys[i].objectid, c->keys[i].flags, c->keys[i].offset, c->blockptrs[i]); fflush(stdout); } for (i = 0; i < nr; i++) { - struct node *next = read_block(c->blockptrs[i]); + struct tree_buffer *next_buf = read_tree_block(root, + c->blockptrs[i]); + struct node *next = &next_buf->node; if (is_leaf(next->header.flags) && node_level(c->header.flags) != 1) BUG(); if (node_level(next->header.flags) != node_level(c->header.flags) - 1) BUG(); - print_tree(next); + print_tree(root, next_buf); + tree_block_release(root, next_buf); } } @@ -746,23 +830,24 @@ int next_key(int i, int max_key) { } int main() { - struct leaf *first_node = malloc(sizeof(struct leaf)); - struct ctree_root root; + struct ctree_root *root; struct key ins; struct key last = { (u64)-1, 0, 0}; char *buf; int i; int num; int ret; - int run_size = 100000; + int run_size = 1000000; int max_key = 100000000; int tree_size = 0; struct ctree_path path; + radix_tree_init(); + + + root = open_ctree("dbfile"); srand(55); - root.node = (struct node *)first_node; - memset(first_node, 0, sizeof(*first_node)); for (i = 0; i < run_size; i++) { buf = malloc(64); num = next_key(i, max_key); @@ -772,39 +857,46 @@ int main() { ins.objectid = num; ins.offset = 0; ins.flags = 0; - ret = insert_item(&root, &ins, buf, strlen(buf)); + ret = insert_item(root, &ins, buf, strlen(buf)); if (!ret) tree_size++; } + close_ctree(root); + root = open_ctree("dbfile"); + printf("starting search\n"); srand(55); for (i = 0; i < run_size; i++) { num = next_key(i, max_key); ins.objectid = num; init_path(&path); - ret = search_slot(&root, &ins, &path); + ret = search_slot(root, &ins, &path); if (ret) { - print_tree(root.node); + print_tree(root, root->node); printf("unable to find %d\n", num); exit(1); } - } - printf("node %p level %d total ptrs %d free spc %lu\n", root.node, - node_level(root.node->header.flags), root.node->header.nritems, - NODEPTRS_PER_BLOCK - root.node->header.nritems); - // print_tree(root.node); - printf("all searches good\n"); + release_path(root, &path); + } + close_ctree(root); + root = open_ctree("dbfile"); + printf("node %p level %d total ptrs %d free spc %lu\n", root->node, + node_level(root->node->node.header.flags), + root->node->node.header.nritems, + NODEPTRS_PER_BLOCK - root->node->node.header.nritems); + printf("all searches good, deleting some items\n"); i = 0; srand(55); for (i = 0 ; i < run_size/4; i++) { num = next_key(i, max_key); ins.objectid = num; init_path(&path); - ret = search_slot(&root, &ins, &path); + ret = search_slot(root, &ins, &path); if (ret) continue; - ret = del_item(&root, &path); + ret = del_item(root, &path); if (ret != 0) BUG(); + release_path(root, &path); tree_size--; } srand(128); @@ -813,38 +905,58 @@ int main() { num = next_key(i, max_key); sprintf(buf, "string-%d", num); ins.objectid = num; - ret = insert_item(&root, &ins, buf, strlen(buf)); + ret = insert_item(root, &ins, buf, strlen(buf)); if (!ret) tree_size++; } - while(root.node) { + close_ctree(root); + root = open_ctree("dbfile"); + printf("starting search2\n"); + srand(128); + for (i = 0; i < run_size; i++) { + num = next_key(i, max_key); + ins.objectid = num; + init_path(&path); + ret = search_slot(root, &ins, &path); + if (ret) { + print_tree(root, root->node); + printf("unable to find %d\n", num); + exit(1); + } + release_path(root, &path); + } + printf("starting big long delete run\n"); + while(root->node && root->node->node.header.nritems > 0) { struct leaf *leaf; int slot; ins.objectid = (u64)-1; init_path(&path); - ret = search_slot(&root, &ins, &path); + ret = search_slot(root, &ins, &path); if (ret == 0) BUG(); - leaf = (struct leaf *)(path.nodes[0]); + leaf = &path.nodes[0]->leaf; slot = path.slots[0]; if (slot != leaf->header.nritems) BUG(); while(path.slots[0] > 0) { path.slots[0] -= 1; slot = path.slots[0]; - leaf = (struct leaf *)(path.nodes[0]); + leaf = &path.nodes[0]->leaf; if (comp_keys(&last, &leaf->items[slot].key) <= 0) BUG(); memcpy(&last, &leaf->items[slot].key, sizeof(last)); - ret = del_item(&root, &path); - if (ret != 0) + ret = del_item(root, &path); + if (ret != 0) { + printf("del_item returned %d\n", ret); BUG(); + } tree_size--; } + release_path(root, &path); } - print_tree(root.node); + close_ctree(root); printf("tree size is now %d\n", tree_size); return 0; } diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h new file mode 100644 index 000000000000..586bf1866042 --- /dev/null +++ b/fs/btrfs/ctree.h @@ -0,0 +1,62 @@ +#ifndef __CTREE__ +#define __CTREE__ + +#define CTREE_BLOCKSIZE 4096 + +struct key { + u64 objectid; + u32 flags; + u64 offset; +} __attribute__ ((__packed__)); + +struct header { + u64 fsid[2]; /* FS specific uuid */ + u64 blocknr; + u64 parentid; + u32 csum; + u32 ham; + u16 nritems; + u16 flags; +} __attribute__ ((__packed__)); + +#define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct header)) / \ + (sizeof(struct key) + sizeof(u64))) + +#define LEVEL_BITS 3 +#define MAX_LEVEL (1 << LEVEL_BITS) +#define node_level(f) ((f) & (MAX_LEVEL-1)) +#define is_leaf(f) (node_level(f) == 0) + +struct tree_buffer; +struct ctree_root { + struct tree_buffer *node; + int fp; + struct radix_tree_root cache_radix; +}; + +struct item { + struct key key; + u16 offset; + u16 size; +} __attribute__ ((__packed__)); + +#define LEAF_DATA_SIZE (CTREE_BLOCKSIZE - sizeof(struct header)) +struct leaf { + struct header header; + union { + struct item items[LEAF_DATA_SIZE/sizeof(struct item)]; + u8 data[CTREE_BLOCKSIZE-sizeof(struct header)]; + }; +} __attribute__ ((__packed__)); + +struct node { + struct header header; + struct key keys[NODEPTRS_PER_BLOCK]; + u64 blockptrs[NODEPTRS_PER_BLOCK]; +} __attribute__ ((__packed__)); + +struct ctree_path { + struct tree_buffer *nodes[MAX_LEVEL]; + int slots[MAX_LEVEL]; +}; +#endif diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c new file mode 100644 index 000000000000..8d51a07051d9 --- /dev/null +++ b/fs/btrfs/disk-io.c @@ -0,0 +1,174 @@ +#define _XOPEN_SOURCE 500 +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#include "kerncompat.h" +#include "radix-tree.h" +#include "ctree.h" +#include "disk-io.h" + +static int allocated_blocks = 0; + +struct ctree_header { + u64 root_block; +} __attribute__ ((__packed__)); + +static int get_free_block(struct ctree_root *root, u64 *block) +{ + struct stat st; + int ret; + + st.st_size = 0; + ret = fstat(root->fp, &st); + if (st.st_size > sizeof(struct ctree_header)) { + *block = (st.st_size - + sizeof(struct ctree_header)) / CTREE_BLOCKSIZE; + } else { + *block = 0; + } + ret = ftruncate(root->fp, sizeof(struct ctree_header) + (*block + 1) * + CTREE_BLOCKSIZE); + return ret; +} + +struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr) +{ + struct tree_buffer *buf; + int ret; + buf = malloc(sizeof(struct tree_buffer)); + if (!buf) + return buf; + allocated_blocks++; + buf->blocknr = blocknr; + buf->count = 1; + radix_tree_preload(GFP_KERNEL); + ret = radix_tree_insert(&root->cache_radix, blocknr, buf); + radix_tree_preload_end(); + if (ret) { + free(buf); + return NULL; + } + return buf; +} + +struct tree_buffer *alloc_free_block(struct ctree_root *root) +{ + u64 free_block; + int ret; + struct tree_buffer * buf; + ret = get_free_block(root, &free_block); + if (ret) { + BUG(); + return NULL; + } + buf = alloc_tree_block(root, free_block); + if (!buf) + BUG(); + return buf; +} + +struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr) +{ + loff_t offset = blocknr * CTREE_BLOCKSIZE + sizeof(struct ctree_header); + struct tree_buffer *buf; + int ret; + + buf = radix_tree_lookup(&root->cache_radix, blocknr); + if (buf) { + buf->count++; + if (buf->blocknr != blocknr) + BUG(); + if (buf->blocknr != buf->node.header.blocknr) + BUG(); + return buf; + } + buf = alloc_tree_block(root, blocknr); + if (!buf) + return NULL; + ret = pread(root->fp, &buf->node, CTREE_BLOCKSIZE, offset); + if (ret != CTREE_BLOCKSIZE) { + free(buf); + return NULL; + } + if (buf->blocknr != buf->node.header.blocknr) + BUG(); + return buf; +} + +int write_tree_block(struct ctree_root *root, struct tree_buffer *buf) +{ + u64 blocknr = buf->blocknr; + loff_t offset = blocknr * CTREE_BLOCKSIZE + sizeof(struct ctree_header); + int ret; + + if (buf->blocknr != buf->node.header.blocknr) + BUG(); + ret = pwrite(root->fp, &buf->node, CTREE_BLOCKSIZE, offset); + if (ret != CTREE_BLOCKSIZE) + return ret; + if (buf == root->node) + return update_root_block(root); + return 0; +} + +struct ctree_root *open_ctree(char *filename) +{ + struct ctree_root *root = malloc(sizeof(struct ctree_root)); + int fp; + u64 root_block; + int ret; + + fp = open(filename, O_CREAT | O_RDWR); + if (fp < 0) { + free(root); + return NULL; + } + root->fp = fp; + INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL); + ret = pread(fp, &root_block, sizeof(u64), 0); + if (ret == sizeof(u64)) { + printf("reading root node at block %lu\n", root_block); + root->node = read_tree_block(root, root_block); + } else + root->node = NULL; + return root; +} + +int close_ctree(struct ctree_root *root) +{ + close(root->fp); + if (root->node) + tree_block_release(root, root->node); + free(root); + printf("on close %d blocks are allocated\n", allocated_blocks); + return 0; +} + +int update_root_block(struct ctree_root *root) +{ + int ret; + u64 root_block = root->node->blocknr; + + ret = pwrite(root->fp, &root_block, sizeof(u64), 0); + if (ret != sizeof(u64)) + return ret; + return 0; +} + +void tree_block_release(struct ctree_root *root, struct tree_buffer *buf) +{ + buf->count--; + if (buf->count == 0) { + if (!radix_tree_lookup(&root->cache_radix, buf->blocknr)) + BUG(); + radix_tree_delete(&root->cache_radix, buf->blocknr); + memset(buf, 0, sizeof(*buf)); + free(buf); + BUG_ON(allocated_blocks == 0); + allocated_blocks--; + } +} + diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h new file mode 100644 index 000000000000..ee95fa05c4a3 --- /dev/null +++ b/fs/btrfs/disk-io.h @@ -0,0 +1,21 @@ +#ifndef __DISKIO__ +#define __DISKIO__ + +struct tree_buffer { + u64 blocknr; + int count; + union { + struct node node; + struct leaf leaf; + }; +}; + +struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr); +int write_tree_block(struct ctree_root *root, struct tree_buffer *buf); +struct ctree_root *open_ctree(char *filename); +int close_ctree(struct ctree_root *root); +void tree_block_release(struct ctree_root *root, struct tree_buffer *buf); +struct tree_buffer *alloc_free_block(struct ctree_root *root); +int update_root_block(struct ctree_root *root); + +#endif diff --git a/fs/btrfs/kerncompat.h b/fs/btrfs/kerncompat.h index 3a4bb4d661f9..347ca06205c2 100644 --- a/fs/btrfs/kerncompat.h +++ b/fs/btrfs/kerncompat.h @@ -6,6 +6,7 @@ #define BITS_PER_LONG 64 #define __GFP_BITS_SHIFT 20 #define __GFP_BITS_MASK ((int)((1 << __GFP_BITS_SHIFT) - 1)) +#define GFP_KERNEL 0 #define __read_mostly #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) #define __force diff --git a/fs/btrfs/radix-tree.c b/fs/btrfs/radix-tree.c new file mode 100644 index 000000000000..baa25ca1c2ac --- /dev/null +++ b/fs/btrfs/radix-tree.c @@ -0,0 +1,836 @@ +/* + * Copyright (C) 2001 Momchil Velikov + * Portions Copyright (C) 2001 Christoph Hellwig + * Copyright (C) 2005 SGI, Christoph Lameter <clameter@sgi.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include "kerncompat.h" +#include "radix-tree.h" +#ifdef __KERNEL__ +#define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) +#else +#define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ +#endif + +#define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) +#define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) + +#define RADIX_TREE_TAG_LONGS \ + ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) + +struct radix_tree_node { + unsigned int count; + void *slots[RADIX_TREE_MAP_SIZE]; + unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; +}; + +struct radix_tree_path { + struct radix_tree_node *node; + int offset; +}; + +#define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) +#define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2) + +static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly; + +/* + * Per-cpu pool of preloaded nodes + */ +struct radix_tree_preload { + int nr; + struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; +}; +struct radix_tree_preload radix_tree_preloads = { 0, }; + +static inline gfp_t root_gfp_mask(struct radix_tree_root *root) +{ + return root->gfp_mask & __GFP_BITS_MASK; +} + +static int internal_nodes = 0; +/* + * This assumes that the caller has performed appropriate preallocation, and + * that the caller has pinned this thread of control to the current CPU. + */ +static struct radix_tree_node * +radix_tree_node_alloc(struct radix_tree_root *root) +{ + struct radix_tree_node *ret; + ret = malloc(sizeof(struct radix_tree_node)); + if (ret) { + memset(ret, 0, sizeof(struct radix_tree_node)); + internal_nodes++; + } + return ret; +} + +static inline void +radix_tree_node_free(struct radix_tree_node *node) +{ + internal_nodes--; + free(node); +} + +/* + * Load up this CPU's radix_tree_node buffer with sufficient objects to + * ensure that the addition of a single element in the tree cannot fail. On + * success, return zero, with preemption disabled. On error, return -ENOMEM + * with preemption not disabled. + */ +int radix_tree_preload(gfp_t gfp_mask) +{ + struct radix_tree_preload *rtp; + struct radix_tree_node *node; + int ret = -ENOMEM; + + preempt_disable(); + rtp = &__get_cpu_var(radix_tree_preloads); + while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { + preempt_enable(); + node = radix_tree_node_alloc(NULL); + if (node == NULL) + goto out; + preempt_disable(); + rtp = &__get_cpu_var(radix_tree_preloads); + if (rtp->nr < ARRAY_SIZE(rtp->nodes)) + rtp->nodes[rtp->nr++] = node; + else + radix_tree_node_free(node); + } + ret = 0; +out: + return ret; +} + +static inline void tag_set(struct radix_tree_node *node, unsigned int tag, + int offset) +{ + __set_bit(offset, node->tags[tag]); +} + +static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, + int offset) +{ + __clear_bit(offset, node->tags[tag]); +} + +static inline int tag_get(struct radix_tree_node *node, unsigned int tag, + int offset) +{ + return test_bit(offset, node->tags[tag]); +} + +static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) +{ + root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); +} + + +static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) +{ + root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); +} + +static inline void root_tag_clear_all(struct radix_tree_root *root) +{ + root->gfp_mask &= __GFP_BITS_MASK; +} + +static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) +{ + return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); +} + +/* + * Returns 1 if any slot in the node has this tag set. + * Otherwise returns 0. + */ +static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) +{ + int idx; + for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { + if (node->tags[tag][idx]) + return 1; + } + return 0; +} + +/* + * Return the maximum key which can be store into a + * radix tree with height HEIGHT. + */ +static inline unsigned long radix_tree_maxindex(unsigned int height) +{ + return height_to_maxindex[height]; +} + +/* + * Extend a radix tree so it can store key @index. + */ +static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) +{ + struct radix_tree_node *node; + unsigned int height; + int tag; + + /* Figure out what the height should be. */ + height = root->height + 1; + while (index > radix_tree_maxindex(height)) + height++; + + if (root->rnode == NULL) { + root->height = height; + goto out; + } + + do { + if (!(node = radix_tree_node_alloc(root))) + return -ENOMEM; + + /* Increase the height. */ + node->slots[0] = root->rnode; + + /* Propagate the aggregated tag info into the new root */ + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { + if (root_tag_get(root, tag)) + tag_set(node, tag, 0); + } + + node->count = 1; + root->rnode = node; + root->height++; + } while (height > root->height); +out: + return 0; +} + +/** + * radix_tree_insert - insert into a radix tree + * @root: radix tree root + * @index: index key + * @item: item to insert + * + * Insert an item into the radix tree at position @index. + */ +int radix_tree_insert(struct radix_tree_root *root, + unsigned long index, void *item) +{ + struct radix_tree_node *node = NULL, *slot; + unsigned int height, shift; + int offset; + int error; + + /* Make sure the tree is high enough. */ + if (index > radix_tree_maxindex(root->height)) { + error = radix_tree_extend(root, index); + if (error) + return error; + } + + slot = root->rnode; + height = root->height; + shift = (height-1) * RADIX_TREE_MAP_SHIFT; + + offset = 0; /* uninitialised var warning */ + while (height > 0) { + if (slot == NULL) { + /* Have to add a child node. */ + if (!(slot = radix_tree_node_alloc(root))) + return -ENOMEM; + if (node) { + node->slots[offset] = slot; + node->count++; + } else + root->rnode = slot; + } + + /* Go a level down */ + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + node = slot; + slot = node->slots[offset]; + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } + + if (slot != NULL) + return -EEXIST; + + if (node) { + node->count++; + node->slots[offset] = item; + BUG_ON(tag_get(node, 0, offset)); + BUG_ON(tag_get(node, 1, offset)); + } else { + root->rnode = item; + BUG_ON(root_tag_get(root, 0)); + BUG_ON(root_tag_get(root, 1)); + } + + return 0; +} + +static inline void **__lookup_slot(struct radix_tree_root *root, + unsigned long index) +{ + unsigned int height, shift; + struct radix_tree_node **slot; + + height = root->height; + + if (index > radix_tree_maxindex(height)) + return NULL; + + if (height == 0 && root->rnode) + return (void **)&root->rnode; + + shift = (height-1) * RADIX_TREE_MAP_SHIFT; + slot = &root->rnode; + + while (height > 0) { + if (*slot == NULL) + return NULL; + + slot = (struct radix_tree_node **) + ((*slot)->slots + + ((index >> shift) & RADIX_TREE_MAP_MASK)); + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } + + return (void **)slot; +} + +/** + * radix_tree_lookup_slot - lookup a slot in a radix tree + * @root: radix tree root + * @index: index key + * + * Lookup the slot corresponding to the position @index in the radix tree + * @root. This is useful for update-if-exists operations. + */ +void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) +{ + return __lookup_slot(root, index); +} + +/** + * radix_tree_lookup - perform lookup operation on a radix tree + * @root: radix tree root + * @index: index key + * + * Lookup the item at the position @index in the radix tree @root. + */ +void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) +{ + void **slot; + + slot = __lookup_slot(root, index); + return slot != NULL ? *slot : NULL; +} + +/** + * radix_tree_tag_set - set a tag on a radix tree node + * @root: radix tree root + * @index: index key + * @tag: tag index + * + * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) + * corresponding to @index in the radix tree. From + * the root all the way down to the leaf node. + * + * Returns the address of the tagged item. Setting a tag on a not-present + * item is a bug. + */ +void *radix_tree_tag_set(struct radix_tree_root *root, + unsigned long index, unsigned int tag) +{ + unsigned int height, shift; + struct radix_tree_node *slot; + + height = root->height; + BUG_ON(index > radix_tree_maxindex(height)); + + slot = root->rnode; + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + + while (height > 0) { + int offset; + + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + if (!tag_get(slot, tag, offset)) + tag_set(slot, tag, offset); + slot = slot->slots[offset]; + BUG_ON(slot == NULL); + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } + + /* set the root's tag bit */ + if (slot && !root_tag_get(root, tag)) + root_tag_set(root, tag); + + return slot; +} + +/** + * radix_tree_tag_clear - clear a tag on a radix tree node + * @root: radix tree root + * @index: index key + * @tag: tag index + * + * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) + * corresponding to @index in the radix tree. If + * this causes the leaf node to have no tags set then clear the tag in the + * next-to-leaf node, etc. + * + * Returns the address of the tagged item on success, else NULL. ie: + * has the same return value and semantics as radix_tree_lookup(). + */ +void *radix_tree_tag_clear(struct radix_tree_root *root, + unsigned long index, unsigned int tag) +{ + struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; + struct radix_tree_node *slot = NULL; + unsigned int height, shift; + + height = root->height; + if (index > radix_tree_maxindex(height)) + goto out; + + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + pathp->node = NULL; + slot = root->rnode; + + while (height > 0) { + int offset; + + if (slot == NULL) + goto out; + + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + pathp[1].offset = offset; + pathp[1].node = slot; + slot = slot->slots[offset]; + pathp++; + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } + + if (slot == NULL) + goto out; + + while (pathp->node) { + if (!tag_get(pathp->node, tag, pathp->offset)) + goto out; + tag_clear(pathp->node, tag, pathp->offset); + if (any_tag_set(pathp->node, tag)) + goto out; + pathp--; + } + + /* clear the root's tag bit */ + if (root_tag_get(root, tag)) + root_tag_clear(root, tag); + +out: + return slot; +} + +#ifndef __KERNEL__ /* Only the test harness uses this at present */ +/** + * radix_tree_tag_get - get a tag on a radix tree node + * @root: radix tree root + * @index: index key + * @tag: tag index (< RADIX_TREE_MAX_TAGS) + * + * Return values: + * + * 0: tag not present or not set + * 1: tag set + */ +int radix_tree_tag_get(struct radix_tree_root *root, + unsigned long index, unsigned int tag) +{ + unsigned int height, shift; + struct radix_tree_node *slot; + int saw_unset_tag = 0; + + height = root->height; + if (index > radix_tree_maxindex(height)) + return 0; + + /* check the root's tag bit */ + if (!root_tag_get(root, tag)) + return 0; + + if (height == 0) + return 1; + + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + slot = root->rnode; + + for ( ; ; ) { + int offset; + + if (slot == NULL) + return 0; + + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + + /* + * This is just a debug check. Later, we can bale as soon as + * we see an unset tag. + */ + if (!tag_get(slot, tag, offset)) + saw_unset_tag = 1; + if (height == 1) { + int ret = tag_get(slot, tag, offset); + + BUG_ON(ret && saw_unset_tag); + return !!ret; + } + slot = slot->slots[offset]; + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } +} +#endif + +static unsigned int +__lookup(struct radix_tree_root *root, void **results, unsigned long index, + unsigned int max_items, unsigned long *next_index) +{ + unsigned int nr_found = 0; + unsigned int shift, height; + struct radix_tree_node *slot; + unsigned long i; + + height = root->height; + if (height == 0) { + if (root->rnode && index == 0) + results[nr_found++] = root->rnode; + goto out; + } + + shift = (height-1) * RADIX_TREE_MAP_SHIFT; + slot = root->rnode; + + for ( ; height > 1; height--) { + + for (i = (index >> shift) & RADIX_TREE_MAP_MASK ; + i < RADIX_TREE_MAP_SIZE; i++) { + if (slot->slots[i] != NULL) + break; + index &= ~((1UL << shift) - 1); + index += 1UL << shift; + if (index == 0) + goto out; /* 32-bit wraparound */ + } + if (i == RADIX_TREE_MAP_SIZE) + goto out; + + shift -= RADIX_TREE_MAP_SHIFT; + slot = slot->slots[i]; + } + + /* Bottom level: grab some items */ + for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { + index++; + if (slot->slots[i]) { + results[nr_found++] = slot->slots[i]; + if (nr_found == max_items) + goto out; + } + } +out: + *next_index = index; + return nr_found; +} + +/** + * radix_tree_gang_lookup - perform multiple lookup on a radix tree + * @root: radix tree root + * @results: where the results of the lookup are placed + * @first_index: start the lookup from this key + * @max_items: place up to this many items at *results + * + * Performs an index-ascending scan of the tree for present items. Places + * them at *@results and returns the number of items which were placed at + * *@results. + * + * The implementation is naive. + */ +unsigned int +radix_tree_gang_lookup(struct radix_tree_root *root, void **results, + unsigned long first_index, unsigned int max_items) +{ + const unsigned long max_index = radix_tree_maxindex(root->height); + unsigned long cur_index = first_index; + unsigned int ret = 0; + + while (ret < max_items) { + unsigned int nr_found; + unsigned long next_index; /* Index of next search */ + + if (cur_index > max_index) + break; + nr_found = __lookup(root, results + ret, cur_index, + max_items - ret, &next_index); + ret += nr_found; + if (next_index == 0) + break; + cur_index = next_index; + } + return ret; +} + +/* + * FIXME: the two tag_get()s here should use find_next_bit() instead of + * open-coding the search. + */ +static unsigned int +__lookup_tag(struct radix_tree_root *root, void **results, unsigned long index, + unsigned int max_items, unsigned long *next_index, unsigned int tag) +{ + unsigned int nr_found = 0; + unsigned int shift; + unsigned int height = root->height; + struct radix_tree_node *slot; + + if (height == 0) { + if (root->rnode && index == 0) + results[nr_found++] = root->rnode; + goto out; + } + + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + slot = root->rnode; + + do { + unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK; + + for ( ; i < RADIX_TREE_MAP_SIZE; i++) { + if (tag_get(slot, tag, i)) { + BUG_ON(slot->slots[i] == NULL); + break; + } + index &= ~((1UL << shift) - 1); + index += 1UL << shift; + if (index == 0) + goto out; /* 32-bit wraparound */ + } + if (i == RADIX_TREE_MAP_SIZE) + goto out; + height--; + if (height == 0) { /* Bottom level: grab some items */ + unsigned long j = index & RADIX_TREE_MAP_MASK; + + for ( ; j < RADIX_TREE_MAP_SIZE; j++) { + index++; + if (tag_get(slot, tag, j)) { + BUG_ON(slot->slots[j] == NULL); + results[nr_found++] = slot->slots[j]; + if (nr_found == max_items) + goto out; + } + } + } + shift -= RADIX_TREE_MAP_SHIFT; + slot = slot->slots[i]; + } while (height > 0); +out: + *next_index = index; + return nr_found; +} + +/** + * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree + * based on a tag + * @root: radix tree root + * @results: where the results of the lookup are placed + * @first_index: start the lookup from this key + * @max_items: place up to this many items at *results + * @tag: the tag index (< RADIX_TREE_MAX_TAGS) + * + * Performs an index-ascending scan of the tree for present items which + * have the tag indexed by @tag set. Places the items at *@results and + * returns the number of items which were placed at *@results. + */ +unsigned int +radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, + unsigned long first_index, unsigned int max_items, + unsigned int tag) +{ + const unsigned long max_index = radix_tree_maxindex(root->height); + unsigned long cur_index = first_index; + unsigned int ret = 0; + + /* check the root's tag bit */ + if (!root_tag_get(root, tag)) + return 0; + + while (ret < max_items) { + unsigned int nr_found; + unsigned long next_index; /* Index of next search */ + + if (cur_index > max_index) + break; + nr_found = __lookup_tag(root, results + ret, cur_index, + max_items - ret, &next_index, tag); + ret += nr_found; + if (next_index == 0) + break; + cur_index = next_index; + } + return ret; +} + +/** + * radix_tree_shrink - shrink height of a radix tree to minimal + * @root radix tree root + */ +static inline void radix_tree_shrink(struct radix_tree_root *root) +{ + /* try to shrink tree height */ + while (root->height > 0 && + root->rnode->count == 1 && + root->rnode->slots[0]) { + struct radix_tree_node *to_free = root->rnode; + + root->rnode = to_free->slots[0]; + root->height--; + /* must only free zeroed nodes into the slab */ + tag_clear(to_free, 0, 0); + tag_clear(to_free, 1, 0); + to_free->slots[0] = NULL; + to_free->count = 0; + radix_tree_node_free(to_free); + } +} + +/** + * radix_tree_delete - delete an item from a radix tree + * @root: radix tree root + * @index: index key + * + * Remove the item at @index from the radix tree rooted at @root. + * + * Returns the address of the deleted item, or NULL if it was not present. + */ +void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) +{ + struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; + struct radix_tree_node *slot = NULL; + unsigned int height, shift; + int tag; + int offset; + + height = root->height; + if (index > radix_tree_maxindex(height)) + goto out; + + slot = root->rnode; + if (height == 0 && root->rnode) { + root_tag_clear_all(root); + root->rnode = NULL; + goto out; + } + + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + pathp->node = NULL; + + do { + if (slot == NULL) + goto out; + + pathp++; + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + pathp->offset = offset; + pathp->node = slot; + slot = slot->slots[offset]; + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } while (height > 0); + + if (slot == NULL) + goto out; + + /* + * Clear all tags associated with the just-deleted item + */ + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { + if (tag_get(pathp->node, tag, pathp->offset)) + radix_tree_tag_clear(root, index, tag); + } + + /* Now free the nodes we do not need anymore */ + while (pathp->node) { + pathp->node->slots[pathp->offset] = NULL; + pathp->node->count--; + + if (pathp->node->count) { + if (pathp->node == root->rnode) + radix_tree_shrink(root); + goto out; + } + + /* Node with zero slots in use so free it */ + radix_tree_node_free(pathp->node); + + pathp--; + } + root_tag_clear_all(root); + root->height = 0; + root->rnode = NULL; + +out: + return slot; +} + +/** + * radix_tree_tagged - test whether any items in the tree are tagged + * @root: radix tree root + * @tag: tag to test + */ +int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) +{ + return root_tag_get(root, tag); +} + +static unsigned long __maxindex(unsigned int height) +{ + unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; + unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; + + if (tmp >= RADIX_TREE_INDEX_BITS) + index = ~0UL; + return index; +} + +static void radix_tree_init_maxindex(void) +{ + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) + height_to_maxindex[i] = __maxindex(i); +} + +void radix_tree_init(void) +{ + radix_tree_init_maxindex(); +} diff --git a/fs/btrfs/radix-tree.h b/fs/btrfs/radix-tree.h new file mode 100644 index 000000000000..c3ce88137f77 --- /dev/null +++ b/fs/btrfs/radix-tree.h @@ -0,0 +1,73 @@ +/* + * Copyright (C) 2001 Momchil Velikov + * Portions Copyright (C) 2001 Christoph Hellwig + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ +#ifndef _LINUX_RADIX_TREE_H +#define _LINUX_RADIX_TREE_H + +#define RADIX_TREE_MAX_TAGS 2 + +/* root tags are stored in gfp_mask, shifted by __GFP_BITS_SHIFT */ +struct radix_tree_root { + unsigned int height; + gfp_t gfp_mask; + struct radix_tree_node *rnode; +}; + +#define RADIX_TREE_INIT(mask) { \ + .height = 0, \ + .gfp_mask = (mask), \ + .rnode = NULL, \ +} + +#define RADIX_TREE(name, mask) \ + struct radix_tree_root name = RADIX_TREE_INIT(mask) + +#define INIT_RADIX_TREE(root, mask) \ +do { \ + (root)->height = 0; \ + (root)->gfp_mask = (mask); \ + (root)->rnode = NULL; \ +} while (0) + +int radix_tree_insert(struct radix_tree_root *, unsigned long, void *); +void *radix_tree_lookup(struct radix_tree_root *, unsigned long); +void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long); +void *radix_tree_delete(struct radix_tree_root *, unsigned long); +unsigned int +radix_tree_gang_lookup(struct radix_tree_root *root, void **results, + unsigned long first_index, unsigned int max_items); +int radix_tree_preload(gfp_t gfp_mask); +void radix_tree_init(void); +void *radix_tree_tag_set(struct radix_tree_root *root, + unsigned long index, unsigned int tag); +void *radix_tree_tag_clear(struct radix_tree_root *root, + unsigned long index, unsigned int tag); +int radix_tree_tag_get(struct radix_tree_root *root, + unsigned long index, unsigned int tag); +unsigned int +radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, + unsigned long first_index, unsigned int max_items, + unsigned int tag); +int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag); + +static inline void radix_tree_preload_end(void) +{ + preempt_enable(); +} + +#endif /* _LINUX_RADIX_TREE_H */ |