NeilBrown: Grow: update backup-metadata mtime every time we write it.

[Martin F. Krafft]

Module: mdadm
Branch: build
Commit: 9739642288555dae607ee4aa0eec0e9245cecf74
URL:    http://git.debian.org/?p=pkg-mdadm/mdadm.git;a=commit;h=9739642288555dae607ee4aa0eec0e9245cecf74

Author: NeilBrown <neilb at suse.de>
Date:   Thu Oct 22 10:42:06 2009 +1100

Grow: update backup-metadata mtime every time we write it.

Originally the backup-metadata was only written once at the
start of a raid5 reshape that made the array bigger.  So we only
set the mtime once.

Now that we can be writing metadata continually during an in-place
reshape, we need to update the mtime more often.

Also, allow the metadata mtime to be slightly in advance of the
array mtime.  Normally the difference will be less than a second,
so 10 minutes should be plenty.  This guards against an old backup
file being used to restart an array.  but starting two reshapes in the
10 minutes is sufficiently unlikely, and the possibility of an
accident is already sufficiently small, that 10 minutes is probably
fine.

Thanks to Guy Martin <gmsoft at tuxicoman.be> for discovering and
reporting that .mtime wasn't being updated properly.

Signed-off-by: NeilBrown <neilb at suse.de>

---

 Grow.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/Grow.c b/Grow.c
index 1111526..f367041 100644
--- a/Grow.c
+++ b/Grow.c
@@ -1246,6 +1246,7 @@ int grow_backup(struct mdinfo *sra,
 
 	if (rv)
 		return rv;
+	bsb.mtime = __cpu_to_le64(time(0));
 	for (i = 0; i < dests; i++) {
 		bsb.devstart = __cpu_to_le64(destoffsets[i]/512);
 
@@ -1315,6 +1316,7 @@ int wait_backup(struct mdinfo *sra,
 		bsb.arraystart = __cpu_to_le64(0);
 		bsb.length = __cpu_to_le64(0);
 	}
+	bsb.mtime = __cpu_to_le64(time(0));
 	for (i = 0; i < dests; i++) {
 		bsb.devstart = __cpu_to_le64(destoffsets[i]/512);
 		bsb.sb_csum = bsb_csum((char*)&bsb, ((char*)&bsb.sb_csum)-((char*)&bsb));
@@ -1639,8 +1641,8 @@ int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt
 			continue; /* Wrong uuid */
 		}
 
-		if (info->array.utime > __le64_to_cpu(bsb.mtime) + 3600 ||
-		    info->array.utime < __le64_to_cpu(bsb.mtime)) {
+		if (info->array.utime > __le64_to_cpu(bsb.mtime) + 10*60 ||
+		    info->array.utime < __le64_to_cpu(bsb.mtime) - 10*60) {
 			if (verbose)
 				fprintf(stderr, Name ": too-old timestamp on backup-metadata on %s\n", devname);
 			continue; /* time stamp is too bad */