Btrfs: don't keep trying to build clusters if we are fragmented
If we are extremely fragmented then we won't be able to create a free_cluster.
So if this happens set last_ptr->fragmented so that all future allcations will
give up trying to create a cluster. When we unpin extents we will unset
->fragmented if we free up a sufficient amount of space in a block group.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9f18eb0..4757645 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6142,6 +6142,34 @@
update_global_block_rsv(fs_info);
}
+/*
+ * Returns the free cluster for the given space info and sets empty_cluster to
+ * what it should be based on the mount options.
+ */
+static struct btrfs_free_cluster *
+fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
+ u64 *empty_cluster)
+{
+ struct btrfs_free_cluster *ret = NULL;
+ bool ssd = btrfs_test_opt(root, SSD);
+
+ *empty_cluster = 0;
+ if (btrfs_mixed_space_info(space_info))
+ return ret;
+
+ if (ssd)
+ *empty_cluster = 2 * 1024 * 1024;
+ if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
+ ret = &root->fs_info->meta_alloc_cluster;
+ if (!ssd)
+ *empty_cluster = 64 * 1024;
+ } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
+ ret = &root->fs_info->data_alloc_cluster;
+ }
+
+ return ret;
+}
+
static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
const bool return_free_space)
{
@@ -6149,7 +6177,10 @@
struct btrfs_block_group_cache *cache = NULL;
struct btrfs_space_info *space_info;
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+ struct btrfs_free_cluster *cluster = NULL;
u64 len;
+ u64 total_unpinned = 0;
+ u64 empty_cluster = 0;
bool readonly;
while (start <= end) {
@@ -6158,8 +6189,14 @@
start >= cache->key.objectid + cache->key.offset) {
if (cache)
btrfs_put_block_group(cache);
+ total_unpinned = 0;
cache = btrfs_lookup_block_group(fs_info, start);
BUG_ON(!cache); /* Logic error */
+
+ cluster = fetch_cluster_info(root,
+ cache->space_info,
+ &empty_cluster);
+ empty_cluster <<= 1;
}
len = cache->key.objectid + cache->key.offset - start;
@@ -6172,8 +6209,22 @@
}
start += len;
+ total_unpinned += len;
space_info = cache->space_info;
+ /*
+ * If this space cluster has been marked as fragmented and we've
+ * unpinned enough in this block group to potentially allow a
+ * cluster to be created inside of it go ahead and clear the
+ * fragmented check.
+ */
+ if (cluster && cluster->fragmented &&
+ total_unpinned > empty_cluster) {
+ spin_lock(&cluster->lock);
+ cluster->fragmented = 0;
+ spin_unlock(&cluster->lock);
+ }
+
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
cache->pinned -= len;
@@ -6911,7 +6962,7 @@
struct btrfs_block_group_cache *block_group = NULL;
u64 search_start = 0;
u64 max_extent_size = 0;
- int empty_cluster = 2 * 1024 * 1024;
+ u64 empty_cluster = 0;
struct btrfs_space_info *space_info;
int loop = 0;
int index = __get_raid_index(flags);
@@ -6959,37 +7010,25 @@
spin_unlock(&space_info->lock);
}
- /*
- * If the space info is for both data and metadata it means we have a
- * small filesystem and we can't use the clustering stuff.
- */
- if (btrfs_mixed_space_info(space_info))
- use_cluster = false;
-
- if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
- last_ptr = &root->fs_info->meta_alloc_cluster;
- if (!btrfs_test_opt(root, SSD))
- empty_cluster = 64 * 1024;
- }
-
- if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
- btrfs_test_opt(root, SSD)) {
- last_ptr = &root->fs_info->data_alloc_cluster;
- }
-
+ last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
if (last_ptr) {
spin_lock(&last_ptr->lock);
if (last_ptr->block_group)
hint_byte = last_ptr->window_start;
+ if (last_ptr->fragmented) {
+ /*
+ * We still set window_start so we can keep track of the
+ * last place we found an allocation to try and save
+ * some time.
+ */
+ hint_byte = last_ptr->window_start;
+ use_cluster = false;
+ }
spin_unlock(&last_ptr->lock);
}
search_start = max(search_start, first_logical_byte(root, 0));
search_start = max(search_start, hint_byte);
-
- if (!last_ptr)
- empty_cluster = 0;
-
if (search_start == hint_byte) {
block_group = btrfs_lookup_block_group(root->fs_info,
search_start);
@@ -7074,7 +7113,7 @@
* Ok we want to try and use the cluster allocator, so
* lets look there
*/
- if (last_ptr) {
+ if (last_ptr && use_cluster) {
struct btrfs_block_group_cache *used_block_group;
unsigned long aligned_cluster;
/*
@@ -7200,6 +7239,16 @@
}
unclustered_alloc:
+ /*
+ * We are doing an unclustered alloc, set the fragmented flag so
+ * we don't bother trying to setup a cluster again until we get
+ * more space.
+ */
+ if (unlikely(last_ptr)) {
+ spin_lock(&last_ptr->lock);
+ last_ptr->fragmented = 1;
+ spin_unlock(&last_ptr->lock);
+ }
spin_lock(&block_group->free_space_ctl->tree_lock);
if (cached &&
block_group->free_space_ctl->free_space <
@@ -7361,6 +7410,11 @@
} else if (!ins->objectid) {
ret = -ENOSPC;
} else if (ins->objectid) {
+ if (!use_cluster && last_ptr) {
+ spin_lock(&last_ptr->lock);
+ last_ptr->window_start = ins->objectid;
+ spin_unlock(&last_ptr->lock);
+ }
ret = 0;
}
out: