Add config option to enable 'fsync()' of object files

As explained in the documentation[*] this is totally useless on
filesystems that do ordered/journalled data writes, but it can be a
useful safety feature on filesystems like HFS+ that only journal the
metadata, not the actual file contents.

It defaults to off, although we could presumably in theory some day
auto-enable it on a per-filesystem basis.

[*] Yes, I updated the docs for the thing.  Hell really _has_ frozen
    over, and the four horsemen are probably just beyond the horizon.
    EVERYBODY PANIC!

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 5331b450e..2466ecfc6 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -372,6 +372,14 @@ core.whitespace::
   does not trigger if the character before such a carriage-return
   is not a whitespace (not enabled by default).
 
+core.fsyncobjectfiles::
+	This boolean will enable 'fsync()' when writing object files.
++
+This is a total waste of time and effort on a filesystem that orders
+data writes properly, but can be useful for filesystems that do not use
+journalling (traditional UNIX filesystems) or that only journal metadata
+and not file contents (OS X's HFS+, or Linux ext3 with "data=writeback").
+
 alias.*::
 	Command aliases for the linkgit:git[1] command wrapper - e.g.
 	after defining "alias.last = cat-file commit HEAD", the invocation