3 files changed, 36 insertions, 17 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e2287c7c10be..aa31fe97c47a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4838,7 +4838,7 @@ static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
 
         /* If we're just plain full then async reclaim just slows us down. */
-        if (space_info->bytes_used >= thresh)
+        if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
                 return 0;
 
         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
@@ -5373,27 +5373,33 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
 
         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
 
-        num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
-                    sinfo->bytes_reserved + sinfo->bytes_readonly +
-                    sinfo->bytes_may_use;
-
-        if (sinfo->total_bytes > num_bytes) {
-                num_bytes = sinfo->total_bytes - num_bytes;
-                block_rsv->reserved += num_bytes;
-                sinfo->bytes_may_use += num_bytes;
-                trace_btrfs_space_reservation(fs_info, "space_info",
-                                      sinfo->flags, num_bytes, 1);
-        }
-
-        if (block_rsv->reserved >= block_rsv->size) {
+        if (block_rsv->reserved < block_rsv->size) {
+                num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
+                        sinfo->bytes_reserved + sinfo->bytes_readonly +
+                        sinfo->bytes_may_use;
+                if (sinfo->total_bytes > num_bytes) {
+                        num_bytes = sinfo->total_bytes - num_bytes;
+                        num_bytes = min(num_bytes,
+                                        block_rsv->size - block_rsv->reserved);
+                        block_rsv->reserved += num_bytes;
+                        sinfo->bytes_may_use += num_bytes;
+                        trace_btrfs_space_reservation(fs_info, "space_info",
+                                                      sinfo->flags, num_bytes,
+                                                      1);
+                }
+        } else if (block_rsv->reserved > block_rsv->size) {
                 num_bytes = block_rsv->reserved - block_rsv->size;
                 sinfo->bytes_may_use -= num_bytes;
                 trace_btrfs_space_reservation(fs_info, "space_info",
                                       sinfo->flags, num_bytes, 0);
                 block_rsv->reserved = block_rsv->size;
-                block_rsv->full = 1;
         }
 
+        if (block_rsv->reserved == block_rsv->size)
+                block_rsv->full = 1;
+        else
+                block_rsv->full = 0;
+
         spin_unlock(&block_rsv->lock);
         spin_unlock(&sinfo->lock);
 }
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f8be74037f34..350b77220153 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4212,11 +4212,20 @@ static int truncate_space_check(struct btrfs_trans_handle *trans,
 {
         int ret;
 
+        /*
+         * This is only used to apply pressure to the enospc system, we don't
+         * intend to use this reservation at all.
+         */
         bytes_deleted = btrfs_csum_bytes_to_leaves(root, bytes_deleted);
+        bytes_deleted *= root->nodesize;
         ret = btrfs_block_rsv_add(root, &root->fs_info->trans_block_rsv,
                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
-        if (!ret)
+        if (!ret) {
+                trace_btrfs_space_reservation(root->fs_info, "transaction",
+                                              trans->transid,
+                                              bytes_deleted, 1);
                 trans->bytes_reserved += bytes_deleted;
+        }
         return ret;
 
 }
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index b6031ce474f7..e9e95ef0644f 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -637,6 +637,8 @@ struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
 
         trans->block_rsv = &root->fs_info->trans_block_rsv;
         trans->bytes_reserved = num_bytes;
+        trace_btrfs_space_reservation(root->fs_info, "transaction",
+                                      trans->transid, num_bytes, 1);
 
         return trans;
 }
@@ -1375,7 +1377,9 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
         rsv = trans->block_rsv;
         trans->block_rsv = &pending->block_rsv;
         trans->bytes_reserved = trans->block_rsv->reserved;
-
+        trace_btrfs_space_reservation(root->fs_info, "transaction",
+                                      trans->transid,
+                                      trans->bytes_reserved, 1);
         dentry = pending->dentry;
         parent_inode = pending->dir;
         parent_root = BTRFS_I(parent_inode)->root;