From 40b58d59ad59e34c1393dcc6a8f122e4458932f9 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Wed, 17 Feb 2021 13:05:15 +0000
Subject: [PATCH] lib/file: make pre-allocate detect disk full errors and
 return them

---
 lib/file/preallocate.go         | 6 ++++++
 lib/file/preallocate_unix.go    | 8 ++++----
 lib/file/preallocate_windows.go | 3 +++
 3 files changed, 13 insertions(+), 4 deletions(-)
 create mode 100644 lib/file/preallocate.go

diff --git a/lib/file/preallocate.go b/lib/file/preallocate.go
new file mode 100644
index 000000000..a87c26b20
--- /dev/null
+++ b/lib/file/preallocate.go
@@ -0,0 +1,6 @@
+package file
+
+import "errors"
+
+// ErrDiskFull is returned from PreAllocate when it detects disk full
+var ErrDiskFull = errors.New("preallocate: file too big for remaining disk space")
diff --git a/lib/file/preallocate_unix.go b/lib/file/preallocate_unix.go
index 8c3df5238..c44c869ea 100644
--- a/lib/file/preallocate_unix.go
+++ b/lib/file/preallocate_unix.go
@@ -42,10 +42,10 @@ again:
 		goto again
 
 	}
-	// FIXME could be doing something here
-	// if err == unix.ENOSPC {
-	// 	log.Printf("No space")
-	// }
+	// Wrap important errors
+	if err == unix.ENOSPC {
+		return ErrDiskFull
+	}
 	return err
 }
 
diff --git a/lib/file/preallocate_windows.go b/lib/file/preallocate_windows.go
index f92f9f7f7..847a49a48 100644
--- a/lib/file/preallocate_windows.go
+++ b/lib/file/preallocate_windows.go
@@ -76,6 +76,9 @@ func PreAllocate(size int64, out *os.File) error {
 		uintptr(19), // FileAllocationInformation
 	)
 	if e1 != nil && e1 != syscall.Errno(0) {
+		if e1 == syscall.Errno(windows.ERROR_DISK_FULL) || e1 == syscall.Errno(windows.ERROR_HANDLE_DISK_FULL) {
+			return ErrDiskFull
+		}
 		return errors.Wrap(e1, "preAllocate NtSetInformationFile failed")
 	}