Btrfs: add btrfs_trim_fs() to handle FITRIM
We take an free extent out from allocator, trim it, then put it back,
but before we trim the block group, we should make sure the block group is
cached, so plus a little change to make cache_block_group() run without a
transaction.
Signed-off-by: Li Dongyang <lidongyang@novell.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index f03ef97..0037427 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2178,3 +2178,95 @@
cluster->block_group = NULL;
}
+int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
+ u64 *trimmed, u64 start, u64 end, u64 minlen)
+{
+ struct btrfs_free_space *entry = NULL;
+ struct btrfs_fs_info *fs_info = block_group->fs_info;
+ u64 bytes = 0;
+ u64 actually_trimmed;
+ int ret = 0;
+
+ *trimmed = 0;
+
+ while (start < end) {
+ spin_lock(&block_group->tree_lock);
+
+ if (block_group->free_space < minlen) {
+ spin_unlock(&block_group->tree_lock);
+ break;
+ }
+
+ entry = tree_search_offset(block_group, start, 0, 1);
+ if (!entry)
+ entry = tree_search_offset(block_group,
+ offset_to_bitmap(block_group,
+ start),
+ 1, 1);
+
+ if (!entry || entry->offset >= end) {
+ spin_unlock(&block_group->tree_lock);
+ break;
+ }
+
+ if (entry->bitmap) {
+ ret = search_bitmap(block_group, entry, &start, &bytes);
+ if (!ret) {
+ if (start >= end) {
+ spin_unlock(&block_group->tree_lock);
+ break;
+ }
+ bytes = min(bytes, end - start);
+ bitmap_clear_bits(block_group, entry,
+ start, bytes);
+ if (entry->bytes == 0)
+ free_bitmap(block_group, entry);
+ } else {
+ start = entry->offset + BITS_PER_BITMAP *
+ block_group->sectorsize;
+ spin_unlock(&block_group->tree_lock);
+ ret = 0;
+ continue;
+ }
+ } else {
+ start = entry->offset;
+ bytes = min(entry->bytes, end - start);
+ unlink_free_space(block_group, entry);
+ kfree(entry);
+ }
+
+ spin_unlock(&block_group->tree_lock);
+
+ if (bytes >= minlen) {
+ int update_ret;
+ update_ret = btrfs_update_reserved_bytes(block_group,
+ bytes, 1, 1);
+
+ ret = btrfs_error_discard_extent(fs_info->extent_root,
+ start,
+ bytes,
+ &actually_trimmed);
+
+ btrfs_add_free_space(block_group,
+ start, bytes);
+ if (!update_ret)
+ btrfs_update_reserved_bytes(block_group,
+ bytes, 0, 1);
+
+ if (ret)
+ break;
+ *trimmed += actually_trimmed;
+ }
+ start += bytes;
+ bytes = 0;
+
+ if (fatal_signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ cond_resched();
+ }
+
+ return ret;
+}