Hi,
On an otherwise idle system, create an ext4 filesystem on /dev/sdi,
mount it and wait more than dirty_writeback_centisecs.
Then create a small file (echo something > file); wait
(dirty_expire_centisecs x 2), expect delayed_allocation_blocks to fall
to zero but it remains at 2 over here.
Create another small file (echo something_else > file2); again wait
(dirty_expire_centisecs x 2); check delayed_allocation_blocks which is
now at 4.
Wait a weekend more:
# date; cat /sys/fs/ext4/sdi/delayed_allocation_blocks
Fri May 24 15:33:21 UTC 2013
4
# date; cat /sys/fs/ext4/sdi/delayed_allocation_blocks
Mon May 27 07:14:30 UTC 2013
4
Doing a manual sync flushes out all blocks, also adding a sync after
mounting solves the not flushing behaviour (possible patch attached).
Has anyone noticed this before and is this expected behaviour? It looks
like these blocks are not flushed out to disk thus remain in memory and
will be lost upon power failure?
Please Cc on reply as we're not on the list.
Many thanks & best regards,
Bert.
--- fs/super.c.org 2013-05-22 09:45:55.061590168 +0200
+++ fs/super.c 2013-05-22 09:46:03.933589947 +0200
@@ -993,6 +993,7 @@
bdev->bd_super = s;
}
+ sync_filesystem(s);
return dget(s->s_root);
error_s:
