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authorLi Zefan <lizf@cn.fujitsu.com>2011-11-20 07:33:38 -0500
committerChris Mason <chris.mason@oracle.com>2011-11-20 07:42:15 -0500
commit52621cb6ed0e0e14358bb317bda7cd5fbd5c2a27 (patch)
tree5b4bc4c08c9f50e97779fcf527b1a8c7780a9e88 /fs/btrfs/free-space-cache.c
parent0f0fbf1d0e188d129756e9508090af4bdbfde00b (diff)
Btrfs: avoid unnecessary bitmap search for cluster setup
setup_cluster_no_bitmap() searches all the extents and bitmaps starting from offset. Therefore if it returns -ENOSPC, all the bitmaps starting from offset are in the bitmaps list, so it's sufficient to search from this list in setup_cluser_bitmap(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
-rw-r--r--fs/btrfs/free-space-cache.c42
1 files changed, 4 insertions, 38 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 8f792f41fea..8c32434da2c 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2451,7 +2451,6 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space *entry;
- struct rb_node *node;
int ret = -ENOSPC;
u64 bitmap_offset = offset_to_bitmap(ctl, offset);
@@ -2469,10 +2468,6 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
list_add(&entry->list, bitmaps);
}
- /*
- * First check our cached list of bitmaps and see if there is an entry
- * here that will work.
- */
list_for_each_entry(entry, bitmaps, list) {
if (entry->bytes < min_bytes)
continue;
@@ -2483,38 +2478,10 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
}
/*
- * If we do have entries on our list and we are here then we didn't find
- * anything, so go ahead and get the next entry after the last entry in
- * this list and start the search from there.
+ * The bitmaps list has all the bitmaps that record free space
+ * starting after offset, so no more search is required.
*/
- if (!list_empty(bitmaps)) {
- entry = list_entry(bitmaps->prev, struct btrfs_free_space,
- list);
- node = rb_next(&entry->offset_index);
- if (!node)
- return -ENOSPC;
- entry = rb_entry(node, struct btrfs_free_space, offset_index);
- goto search;
- }
-
- entry = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 0, 1);
- if (!entry)
- return -ENOSPC;
-
-search:
- node = &entry->offset_index;
- do {
- entry = rb_entry(node, struct btrfs_free_space, offset_index);
- node = rb_next(&entry->offset_index);
- if (!entry->bitmap)
- continue;
- if (entry->bytes < min_bytes)
- continue;
- ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
- bytes, min_bytes);
- } while (ret && node);
-
- return ret;
+ return -ENOSPC;
}
/*
@@ -2532,8 +2499,8 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
u64 offset, u64 bytes, u64 empty_size)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
- struct list_head bitmaps;
struct btrfs_free_space *entry, *tmp;
+ LIST_HEAD(bitmaps);
u64 min_bytes;
int ret;
@@ -2572,7 +2539,6 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
goto out;
}
- INIT_LIST_HEAD(&bitmaps);
ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
bytes, min_bytes);
if (ret)