To avoid performance degradation on filesystems with "allocate on
flush" semantics (like xfs, ubifs, hfs+, and ext4 without nodelalloc),
start writing back each file once it has finished being extracted.
This doesn't actually wait for the write to finish; it just starts
the writeback.
The sync_file_range call has been available since Linux 2.6.17.
On non-Linux systems we can skip it.
Suggested-by: Ted Ts'o <ty...@mit.edu>
Signed-off-by: Jonathan Nieder <jrnie...@gmail.com>
---
src/archives.c | 16 ++++++++++++++++
1 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/src/archives.c b/src/archives.c
index d68f9d6..d423f45 100644
--- a/src/archives.c
+++ b/src/archives.c
@@ -66,6 +66,20 @@
struct pkginfo *conflictor[MAXCONFLICTORS];
int cflict_index = 0;
+#ifdef SYNC_FILE_RANGE_WRITE
+static int
+begin_writeback(int fd)
+{
+ return sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WRITE);
+}
+#else
+static int
+begin_writeback(int fd)
+{
+ return 0;
+}
+#endif
+
/**
* Special routine to handle partial reads from the tarfile.
*/
@@ -712,6 +726,8 @@ tarobject(void *ctx, struct tar_entry *ti)
ohshite(_("error setting ownership of `%.255s'"), ti->name);
if (fchmod(fd, st->mode & ~S_IFMT))
ohshite(_("error setting permissions of `%.255s'"), ti->name);
+ if (begin_writeback(fd))
+ ohshite(_("error beginning writeback of '%.255s'"), ti->name);
/* Postpone the fsync, to try to avoid massive I/O degradation. */
if (!fc_unsafe_io)
--
1.7.2.3
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