#include <linux/sched.h>
#include "ctree.h"
+#include "free-space-cache.h"
+#include "transaction.h"
+
+struct btrfs_free_space {
+ struct rb_node bytes_index;
+ struct rb_node offset_index;
+ u64 offset;
+ u64 bytes;
+};
static int tree_insert_offset(struct rb_root *root, u64 offset,
struct rb_node *node)
}
/*
- * searches the tree for the given offset. If contains is set we will return
- * the free space that contains the given offset. If contains is not set we
- * will return the free space that starts at or after the given offset and is
- * at least bytes long.
+ * searches the tree for the given offset.
+ *
+ * fuzzy == 1: this is used for allocations where we are given a hint of where
+ * to look for free space. Because the hint may not be completely on an offset
+ * mark, or the hint may no longer point to free space we need to fudge our
+ * results a bit. So we look for free space starting at or after offset with at
+ * least bytes size. We prefer to find as close to the given offset as we can.
+ * Also if the offset is within a free space range, then we will return the free
+ * space that contains the given offset, which means we can return a free space
+ * chunk with an offset before the provided offset.
+ *
+ * fuzzy == 0: this is just a normal tree search. Give us the free space that
+ * starts at the given offset which is at least bytes size, and if its not there
+ * return NULL.
*/
static struct btrfs_free_space *tree_search_offset(struct rb_root *root,
u64 offset, u64 bytes,
- int contains)
+ int fuzzy)
{
struct rb_node *n = root->rb_node;
struct btrfs_free_space *entry, *ret = NULL;
entry = rb_entry(n, struct btrfs_free_space, offset_index);
if (offset < entry->offset) {
- if (!contains &&
+ if (fuzzy &&
(!ret || entry->offset < ret->offset) &&
(bytes <= entry->bytes))
ret = entry;
n = n->rb_left;
} else if (offset > entry->offset) {
- if (contains &&
- (entry->offset + entry->bytes - 1) >= offset) {
+ if (fuzzy &&
+ (entry->offset + entry->bytes - 1) >= offset &&
+ bytes <= entry->bytes) {
ret = entry;
break;
}
int ret = 0;
+ BUG_ON(!info->bytes);
ret = tree_insert_offset(&block_group->free_space_offset, info->offset,
&info->offset_index);
if (ret)
struct btrfs_free_space *right_info;
struct btrfs_free_space *left_info;
struct btrfs_free_space *info = NULL;
- struct btrfs_free_space *alloc_info;
int ret = 0;
- alloc_info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
- if (!alloc_info)
+ info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
+ if (!info)
return -ENOMEM;
+ info->offset = offset;
+ info->bytes = bytes;
+
+ spin_lock(&block_group->tree_lock);
+
/*
* first we want to see if there is free space adjacent to the range we
* are adding, if there is remove that struct and add a new one to
* cover the entire range
*/
- spin_lock(&block_group->lock);
-
right_info = tree_search_offset(&block_group->free_space_offset,
- offset+bytes, 0, 1);
+ offset+bytes, 0, 0);
left_info = tree_search_offset(&block_group->free_space_offset,
offset-1, 0, 1);
- if (right_info && right_info->offset == offset+bytes) {
+ if (right_info) {
unlink_free_space(block_group, right_info);
- info = right_info;
- info->offset = offset;
- info->bytes += bytes;
- } else if (right_info && right_info->offset != offset+bytes) {
- printk(KERN_ERR "adding space in the middle of an existing "
- "free space area. existing: offset=%Lu, bytes=%Lu. "
- "new: offset=%Lu, bytes=%Lu\n", right_info->offset,
- right_info->bytes, offset, bytes);
- BUG();
+ info->bytes += right_info->bytes;
+ kfree(right_info);
}
- if (left_info) {
+ if (left_info && left_info->offset + left_info->bytes == offset) {
unlink_free_space(block_group, left_info);
-
- if (unlikely((left_info->offset + left_info->bytes) !=
- offset)) {
- printk(KERN_ERR "free space to the left of new free "
- "space isn't quite right. existing: offset=%Lu,"
- " bytes=%Lu. new: offset=%Lu, bytes=%Lu\n",
- left_info->offset, left_info->bytes, offset,
- bytes);
- BUG();
- }
-
- if (info) {
- info->offset = left_info->offset;
- info->bytes += left_info->bytes;
- kfree(left_info);
- } else {
- info = left_info;
- info->bytes += bytes;
- }
- }
-
- if (info) {
- ret = link_free_space(block_group, info);
- if (!ret)
- info = NULL;
- goto out;
+ info->offset = left_info->offset;
+ info->bytes += left_info->bytes;
+ kfree(left_info);
}
- info = alloc_info;
- alloc_info = NULL;
- info->offset = offset;
- info->bytes = bytes;
-
ret = link_free_space(block_group, info);
if (ret)
kfree(info);
-out:
- spin_unlock(&block_group->lock);
+
+ spin_unlock(&block_group->tree_lock);
+
if (ret) {
printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret);
if (ret == -EEXIST)
BUG();
}
- if (alloc_info)
- kfree(alloc_info);
-
return ret;
}
struct btrfs_free_space *info;
int ret = 0;
- spin_lock(&block_group->lock);
+ spin_lock(&block_group->tree_lock);
+
info = tree_search_offset(&block_group->free_space_offset, offset, 0,
1);
-
if (info && info->offset == offset) {
if (info->bytes < bytes) {
- printk(KERN_ERR "Found free space at %Lu, size %Lu,"
- "trying to use %Lu\n",
- info->offset, info->bytes, bytes);
+ printk(KERN_ERR "Found free space at %llu, size %llu,"
+ "trying to use %llu\n",
+ (unsigned long long)info->offset,
+ (unsigned long long)info->bytes,
+ (unsigned long long)bytes);
WARN_ON(1);
ret = -EINVAL;
+ spin_unlock(&block_group->tree_lock);
goto out;
}
-
unlink_free_space(block_group, info);
if (info->bytes == bytes) {
kfree(info);
+ spin_unlock(&block_group->tree_lock);
goto out;
}
info->bytes -= bytes;
ret = link_free_space(block_group, info);
+ spin_unlock(&block_group->tree_lock);
+ BUG_ON(ret);
+ } else if (info && info->offset < offset &&
+ info->offset + info->bytes >= offset + bytes) {
+ u64 old_start = info->offset;
+ /*
+ * we're freeing space in the middle of the info,
+ * this can happen during tree log replay
+ *
+ * first unlink the old info and then
+ * insert it again after the hole we're creating
+ */
+ unlink_free_space(block_group, info);
+ if (offset + bytes < info->offset + info->bytes) {
+ u64 old_end = info->offset + info->bytes;
+
+ info->offset = offset + bytes;
+ info->bytes = old_end - info->offset;
+ ret = link_free_space(block_group, info);
+ BUG_ON(ret);
+ } else {
+ /* the hole we're creating ends at the end
+ * of the info struct, just free the info
+ */
+ kfree(info);
+ }
+ spin_unlock(&block_group->tree_lock);
+ /* step two, insert a new info struct to cover anything
+ * before the hole
+ */
+ ret = btrfs_add_free_space(block_group, old_start,
+ offset - old_start);
BUG_ON(ret);
} else {
+ spin_unlock(&block_group->tree_lock);
+ if (!info) {
+ printk(KERN_ERR "couldn't find space %llu to free\n",
+ (unsigned long long)offset);
+ printk(KERN_ERR "cached is %d, offset %llu bytes %llu\n",
+ block_group->cached, block_group->key.objectid,
+ block_group->key.offset);
+ btrfs_dump_free_space(block_group, bytes);
+ } else if (info) {
+ printk(KERN_ERR "hmm, found offset=%llu bytes=%llu, "
+ "but wanted offset=%llu bytes=%llu\n",
+ info->offset, info->bytes, offset, bytes);
+ }
WARN_ON(1);
}
out:
- spin_unlock(&block_group->lock);
return ret;
}
info = rb_entry(n, struct btrfs_free_space, offset_index);
if (info->bytes >= bytes)
count++;
- //printk(KERN_INFO "offset=%Lu, bytes=%Lu\n", info->offset,
- // info->bytes);
+ printk(KERN_ERR "entry offset %llu, bytes %llu\n", info->offset,
+ info->bytes);
}
printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
"\n", count);
return ret;
}
+/*
+ * for a given cluster, put all of its extents back into the free
+ * space cache. If the block group passed doesn't match the block group
+ * pointed to by the cluster, someone else raced in and freed the
+ * cluster already. In that case, we just return without changing anything
+ */
+static int
+__btrfs_return_cluster_to_free_space(
+ struct btrfs_block_group_cache *block_group,
+ struct btrfs_free_cluster *cluster)
+{
+ struct btrfs_free_space *entry;
+ struct rb_node *node;
+
+ spin_lock(&cluster->lock);
+ if (cluster->block_group != block_group)
+ goto out;
+
+ cluster->window_start = 0;
+ node = rb_first(&cluster->root);
+ while(node) {
+ entry = rb_entry(node, struct btrfs_free_space, offset_index);
+ node = rb_next(&entry->offset_index);
+ rb_erase(&entry->offset_index, &cluster->root);
+ link_free_space(block_group, entry);
+ }
+ list_del_init(&cluster->block_group_list);
+
+ btrfs_put_block_group(cluster->block_group);
+ cluster->block_group = NULL;
+ cluster->root.rb_node = NULL;
+out:
+ spin_unlock(&cluster->lock);
+ return 0;
+}
+
void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
{
struct btrfs_free_space *info;
struct rb_node *node;
+ struct btrfs_free_cluster *cluster;
+ struct btrfs_free_cluster *safe;
+
+ spin_lock(&block_group->tree_lock);
+
+ list_for_each_entry_safe(cluster, safe, &block_group->cluster_list,
+ block_group_list) {
+
+ WARN_ON(cluster->block_group != block_group);
+ __btrfs_return_cluster_to_free_space(block_group, cluster);
+ }
- spin_lock(&block_group->lock);
while ((node = rb_last(&block_group->free_space_bytes)) != NULL) {
info = rb_entry(node, struct btrfs_free_space, bytes_index);
unlink_free_space(block_group, info);
kfree(info);
if (need_resched()) {
- spin_unlock(&block_group->lock);
+ spin_unlock(&block_group->tree_lock);
cond_resched();
- spin_lock(&block_group->lock);
+ spin_lock(&block_group->tree_lock);
}
}
- spin_unlock(&block_group->lock);
+ spin_unlock(&block_group->tree_lock);
}
-struct btrfs_free_space *btrfs_find_free_space_offset(struct
- btrfs_block_group_cache
- *block_group, u64 offset,
- u64 bytes)
+u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
+ u64 offset, u64 bytes, u64 empty_size)
{
- struct btrfs_free_space *ret;
+ struct btrfs_free_space *entry = NULL;
+ u64 ret = 0;
- spin_lock(&block_group->lock);
- ret = tree_search_offset(&block_group->free_space_offset, offset,
- bytes, 0);
- spin_unlock(&block_group->lock);
+ spin_lock(&block_group->tree_lock);
+ entry = tree_search_offset(&block_group->free_space_offset, offset,
+ bytes + empty_size, 1);
+ if (!entry)
+ entry = tree_search_bytes(&block_group->free_space_bytes,
+ offset, bytes + empty_size);
+ if (entry) {
+ unlink_free_space(block_group, entry);
+ ret = entry->offset;
+ entry->offset += bytes;
+ entry->bytes -= bytes;
+
+ if (!entry->bytes)
+ kfree(entry);
+ else
+ link_free_space(block_group, entry);
+ }
+ spin_unlock(&block_group->tree_lock);
return ret;
}
-struct btrfs_free_space *btrfs_find_free_space_bytes(struct
- btrfs_block_group_cache
- *block_group, u64 offset,
- u64 bytes)
+/*
+ * given a cluster, put all of its extents back into the free space
+ * cache. If a block group is passed, this function will only free
+ * a cluster that belongs to the passed block group.
+ *
+ * Otherwise, it'll get a reference on the block group pointed to by the
+ * cluster and remove the cluster from it.
+ */
+int btrfs_return_cluster_to_free_space(
+ struct btrfs_block_group_cache *block_group,
+ struct btrfs_free_cluster *cluster)
{
- struct btrfs_free_space *ret;
+ int ret;
+
+ /* first, get a safe pointer to the block group */
+ spin_lock(&cluster->lock);
+ if (!block_group) {
+ block_group = cluster->block_group;
+ if (!block_group) {
+ spin_unlock(&cluster->lock);
+ return 0;
+ }
+ } else if (cluster->block_group != block_group) {
+ /* someone else has already freed it don't redo their work */
+ spin_unlock(&cluster->lock);
+ return 0;
+ }
+ atomic_inc(&block_group->count);
+ spin_unlock(&cluster->lock);
- spin_lock(&block_group->lock);
+ /* now return any extents the cluster had on it */
+ spin_lock(&block_group->tree_lock);
+ ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
+ spin_unlock(&block_group->tree_lock);
- ret = tree_search_bytes(&block_group->free_space_bytes, offset, bytes);
- spin_unlock(&block_group->lock);
+ /* finally drop our ref */
+ btrfs_put_block_group(block_group);
+ return ret;
+}
+/*
+ * given a cluster, try to allocate 'bytes' from it, returns 0
+ * if it couldn't find anything suitably large, or a logical disk offset
+ * if things worked out
+ */
+u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
+ struct btrfs_free_cluster *cluster, u64 bytes,
+ u64 min_start)
+{
+ struct btrfs_free_space *entry = NULL;
+ struct rb_node *node;
+ u64 ret = 0;
+
+ spin_lock(&cluster->lock);
+ if (bytes > cluster->max_size)
+ goto out;
+
+ if (cluster->block_group != block_group)
+ goto out;
+
+ node = rb_first(&cluster->root);
+ if (!node)
+ goto out;
+
+ entry = rb_entry(node, struct btrfs_free_space, offset_index);
+
+ while(1) {
+ if (entry->bytes < bytes || entry->offset < min_start) {
+ struct rb_node *node;
+
+ node = rb_next(&entry->offset_index);
+ if (!node)
+ break;
+ entry = rb_entry(node, struct btrfs_free_space,
+ offset_index);
+ continue;
+ }
+ ret = entry->offset;
+
+ entry->offset += bytes;
+ entry->bytes -= bytes;
+
+ if (entry->bytes == 0) {
+ rb_erase(&entry->offset_index, &cluster->root);
+ kfree(entry);
+ }
+ break;
+ }
+out:
+ spin_unlock(&cluster->lock);
return ret;
}
-struct btrfs_free_space *btrfs_find_free_space(struct btrfs_block_group_cache
- *block_group, u64 offset,
- u64 bytes)
+/*
+ * here we try to find a cluster of blocks in a block group. The goal
+ * is to find at least bytes free and up to empty_size + bytes free.
+ * We might not find them all in one contiguous area.
+ *
+ * returns zero and sets up cluster if things worked out, otherwise
+ * it returns -enospc
+ */
+int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
+ struct btrfs_block_group_cache *block_group,
+ struct btrfs_free_cluster *cluster,
+ u64 offset, u64 bytes, u64 empty_size)
{
- struct btrfs_free_space *ret;
+ struct btrfs_free_space *entry = NULL;
+ struct rb_node *node;
+ struct btrfs_free_space *next;
+ struct btrfs_free_space *last;
+ u64 min_bytes;
+ u64 window_start;
+ u64 window_free;
+ u64 max_extent = 0;
+ int total_retries = 0;
+ int ret;
+
+ /* for metadata, allow allocates with more holes */
+ if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
+ /*
+ * we want to do larger allocations when we are
+ * flushing out the delayed refs, it helps prevent
+ * making more work as we go along.
+ */
+ if (trans->transaction->delayed_refs.flushing)
+ min_bytes = max(bytes, (bytes + empty_size) >> 1);
+ else
+ min_bytes = max(bytes, (bytes + empty_size) >> 4);
+ } else
+ min_bytes = max(bytes, (bytes + empty_size) >> 2);
- spin_lock(&block_group->lock);
- ret = tree_search_offset(&block_group->free_space_offset, offset,
- bytes, 0);
- if (!ret)
- ret = tree_search_bytes(&block_group->free_space_bytes,
- offset, bytes);
+ spin_lock(&block_group->tree_lock);
+ spin_lock(&cluster->lock);
- spin_unlock(&block_group->lock);
+ /* someone already found a cluster, hooray */
+ if (cluster->block_group) {
+ ret = 0;
+ goto out;
+ }
+again:
+ min_bytes = min(min_bytes, bytes + empty_size);
+ entry = tree_search_bytes(&block_group->free_space_bytes,
+ offset, min_bytes);
+ if (!entry) {
+ ret = -ENOSPC;
+ goto out;
+ }
+ window_start = entry->offset;
+ window_free = entry->bytes;
+ last = entry;
+ max_extent = entry->bytes;
+
+ while(1) {
+ /* out window is just right, lets fill it */
+ if (window_free >= bytes + empty_size)
+ break;
+
+ node = rb_next(&last->offset_index);
+ if (!node) {
+ ret = -ENOSPC;
+ goto out;
+ }
+ next = rb_entry(node, struct btrfs_free_space, offset_index);
+
+ /*
+ * we haven't filled the empty size and the window is
+ * very large. reset and try again
+ */
+ if (next->offset - window_start > (bytes + empty_size) * 2) {
+ entry = next;
+ window_start = entry->offset;
+ window_free = entry->bytes;
+ last = entry;
+ max_extent = 0;
+ total_retries++;
+ if (total_retries % 256 == 0) {
+ if (min_bytes >= (bytes + empty_size)) {
+ ret = -ENOSPC;
+ goto out;
+ }
+ /*
+ * grow our allocation a bit, we're not having
+ * much luck
+ */
+ min_bytes *= 2;
+ goto again;
+ }
+ } else {
+ last = next;
+ window_free += next->bytes;
+ if (entry->bytes > max_extent)
+ max_extent = entry->bytes;
+ }
+ }
+
+ cluster->window_start = entry->offset;
+
+ /*
+ * now we've found our entries, pull them out of the free space
+ * cache and put them into the cluster rbtree
+ *
+ * The cluster includes an rbtree, but only uses the offset index
+ * of each free space cache entry.
+ */
+ while(1) {
+ node = rb_next(&entry->offset_index);
+ unlink_free_space(block_group, entry);
+ ret = tree_insert_offset(&cluster->root, entry->offset,
+ &entry->offset_index);
+ BUG_ON(ret);
+
+ if (!node || entry == last)
+ break;
+
+ entry = rb_entry(node, struct btrfs_free_space, offset_index);
+ }
+ ret = 0;
+ cluster->max_size = max_extent;
+ atomic_inc(&block_group->count);
+ list_add_tail(&cluster->block_group_list, &block_group->cluster_list);
+ cluster->block_group = block_group;
+out:
+ spin_unlock(&cluster->lock);
+ spin_unlock(&block_group->tree_lock);
return ret;
}
+
+/*
+ * simple code to zero out a cluster
+ */
+void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
+{
+ spin_lock_init(&cluster->lock);
+ spin_lock_init(&cluster->refill_lock);
+ cluster->root.rb_node = NULL;
+ cluster->max_size = 0;
+ INIT_LIST_HEAD(&cluster->block_group_list);
+ cluster->block_group = NULL;
+}
+
projects / linux-2.6-block.git / blobdiff