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-rw-r--r--fs/btrfs/delayed-ref.c37
1 files changed, 34 insertions, 3 deletions
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 6a13cf00218b..1043f66cc130 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -163,6 +163,8 @@ int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv;
u64 limit = btrfs_calc_delayed_ref_bytes(fs_info, 1);
u64 num_bytes = 0;
+ u64 refilled_bytes;
+ u64 to_free;
int ret = -ENOSPC;
spin_lock(&block_rsv->lock);
@@ -178,9 +180,38 @@ int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, num_bytes, flush);
if (ret)
return ret;
- btrfs_block_rsv_add_bytes(block_rsv, num_bytes, false);
- trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
- 0, num_bytes, 1);
+
+ /*
+ * We may have raced with someone else, so check again if we the block
+ * reserve is still not full and release any excess space.
+ */
+ spin_lock(&block_rsv->lock);
+ if (block_rsv->reserved < block_rsv->size) {
+ u64 needed = block_rsv->size - block_rsv->reserved;
+
+ if (num_bytes >= needed) {
+ block_rsv->reserved += needed;
+ block_rsv->full = true;
+ to_free = num_bytes - needed;
+ refilled_bytes = needed;
+ } else {
+ block_rsv->reserved += num_bytes;
+ to_free = 0;
+ refilled_bytes = num_bytes;
+ }
+ } else {
+ to_free = num_bytes;
+ refilled_bytes = 0;
+ }
+ spin_unlock(&block_rsv->lock);
+
+ if (to_free > 0)
+ btrfs_space_info_free_bytes_may_use(fs_info, block_rsv->space_info,
+ to_free);
+
+ if (refilled_bytes > 0)
+ trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv", 0,
+ refilled_bytes, 1);
return 0;
}