From 2548347bba2d4e6f9947dadf95ed24a16f8a1cdc Mon Sep 17 00:00:00 2001
From: Dominique Martinet <asmadeus@codewreck.org>
Date: Wed, 23 Sep 2020 17:39:19 +0200
Subject: [PATCH] libutil/archive: add preallocate-contents option

Make archive preallocation (fallocate) optional because some filesystems
like btrfs do not behave as expected with fallocate.

See #3550.
---
 src/libutil/archive.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/libutil/archive.cc b/src/libutil/archive.cc
index 14399dea3..cdf3d89ae 100644
--- a/src/libutil/archive.cc
+++ b/src/libutil/archive.cc
@@ -27,6 +27,8 @@ struct ArchiveSettings : Config
         #endif
         "use-case-hack",
         "Whether to enable a Darwin-specific hack for dealing with file name collisions."};
+    Setting<bool> preallocateContents{this, true, "preallocate-contents",
+        "Whether to preallocate files when writing objects with known size."};
 };
 
 static ArchiveSettings archiveSettings;
@@ -325,6 +327,9 @@ struct RestoreSink : ParseSink
 
     void preallocateContents(uint64_t len)
     {
+        if (!archiveSettings.preallocateContents)
+            return;
+
 #if HAVE_POSIX_FALLOCATE
         if (len) {
             errno = posix_fallocate(fd.get(), 0, len);