diff options
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
-rw-r--r-- | fs/btrfs/free-space-cache.c | 530 |
1 files changed, 375 insertions, 155 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index d1e5f0e..768b952 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -18,6 +18,15 @@ #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) @@ -68,14 +77,24 @@ static int tree_insert_bytes(struct rb_root *root, u64 bytes, } /* - * 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; @@ -84,13 +103,14 @@ static struct btrfs_free_space *tree_search_offset(struct rb_root *root, 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 ((entry->offset + entry->bytes - 1) >= offset && + if (fuzzy && + (entry->offset + entry->bytes - 1) >= offset && bytes <= entry->bytes) { ret = entry; break; @@ -171,6 +191,7 @@ static int link_free_space(struct btrfs_block_group_cache *block_group, int ret = 0; + BUG_ON(!info->bytes); ret = tree_insert_offset(&block_group->free_space_offset, info->offset, &info->offset_index); if (ret) @@ -184,108 +205,70 @@ static int link_free_space(struct btrfs_block_group_cache *block_group, return ret; } -static int __btrfs_add_free_space(struct btrfs_block_group_cache *block_group, - u64 offset, u64 bytes) +int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, + u64 offset, u64 bytes) { 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 */ 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 "btrfs adding space in the middle of an " - "existing free space area. existing: " - "offset=%llu, bytes=%llu. new: offset=%llu, " - "bytes=%llu\n", (unsigned long long)right_info->offset, - (unsigned long long)right_info->bytes, - (unsigned long long)offset, - (unsigned long long)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 "btrfs free space to the left " - "of new free space isn't " - "quite right. existing: offset=%llu, " - "bytes=%llu. new: offset=%llu, bytes=%llu\n", - (unsigned long long)left_info->offset, - (unsigned long long)left_info->bytes, - (unsigned long long)offset, - (unsigned long long)bytes); - BUG(); - } - - if (info) { - info->offset = left_info->offset; - info->bytes += left_info->bytes; - kfree(left_info); - } else { - info = left_info; - info->bytes += bytes; - } + info->offset = left_info->offset; + info->bytes += left_info->bytes; + kfree(left_info); } - if (info) { - ret = link_free_space(block_group, info); - if (!ret) - info = NULL; - goto out; - } - - 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->tree_lock); + if (ret) { printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret); - if (ret == -EEXIST) - BUG(); + BUG_ON(ret == -EEXIST); } - kfree(alloc_info); - return ret; } -static int -__btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, - u64 offset, u64 bytes) +int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, + u64 offset, u64 bytes) { struct btrfs_free_space *info; int ret = 0; + 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 %llu, size %llu," @@ -295,12 +278,14 @@ __btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, (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; } @@ -308,6 +293,7 @@ __btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, 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) { @@ -333,70 +319,33 @@ __btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, */ 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); + 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: return ret; } -int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, - u64 offset, u64 bytes) -{ - int ret; - struct btrfs_free_space *sp; - - mutex_lock(&block_group->alloc_mutex); - ret = __btrfs_add_free_space(block_group, offset, bytes); - sp = tree_search_offset(&block_group->free_space_offset, offset, 0, 1); - BUG_ON(!sp); - mutex_unlock(&block_group->alloc_mutex); - - return ret; -} - -int btrfs_add_free_space_lock(struct btrfs_block_group_cache *block_group, - u64 offset, u64 bytes) -{ - int ret; - struct btrfs_free_space *sp; - - ret = __btrfs_add_free_space(block_group, offset, bytes); - sp = tree_search_offset(&block_group->free_space_offset, offset, 0, 1); - BUG_ON(!sp); - - return ret; -} - -int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, - u64 offset, u64 bytes) -{ - int ret = 0; - - mutex_lock(&block_group->alloc_mutex); - ret = __btrfs_remove_free_space(block_group, offset, bytes); - mutex_unlock(&block_group->alloc_mutex); - - return ret; -} - -int btrfs_remove_free_space_lock(struct btrfs_block_group_cache *block_group, - u64 offset, u64 bytes) -{ - int ret; - - ret = __btrfs_remove_free_space(block_group, offset, bytes); - - return ret; -} - void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, u64 bytes) { @@ -408,6 +357,8 @@ void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, info = rb_entry(n, struct btrfs_free_space, offset_index); if (info->bytes >= bytes) count++; + 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); @@ -428,68 +379,337 @@ u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group) 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); + } - mutex_lock(&block_group->alloc_mutex); 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()) { - mutex_unlock(&block_group->alloc_mutex); + spin_unlock(&block_group->tree_lock); cond_resched(); - mutex_lock(&block_group->alloc_mutex); + spin_lock(&block_group->tree_lock); } } - mutex_unlock(&block_group->alloc_mutex); + spin_unlock(&block_group->tree_lock); } -#if 0 -static 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; - mutex_lock(&block_group->alloc_mutex); - ret = tree_search_offset(&block_group->free_space_offset, offset, - bytes, 0); - mutex_unlock(&block_group->alloc_mutex); + 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; } -static 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; - mutex_lock(&block_group->alloc_mutex); + /* 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); - ret = tree_search_bytes(&block_group->free_space_bytes, offset, bytes); - mutex_unlock(&block_group->alloc_mutex); + /* 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); + /* finally drop our ref */ + btrfs_put_block_group(block_group); return ret; } -#endif -struct btrfs_free_space *btrfs_find_free_space(struct btrfs_block_group_cache - *block_group, u64 offset, - u64 bytes) +/* + * 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; +} + +/* + * 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 = NULL; + 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->tree_lock); + spin_lock(&cluster->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; - 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); + 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; +} + |