Hello. On Fri, Oct 28, 2016 at 07:21:58PM +0300, Evgeniy Berdnikov wrote: > On Fri, Oct 28, 2016 at 10:59:42AM -0400, Theodore Ts'o wrote: > > On Fri, Oct 28, 2016 at 10:04:12AM +0200, Oswald Buddenhagen wrote: > > > > As for truncation, this might still happen if the file is not fsynced > > > > explicitly at critical transaction points (including before fclose). > > > > > > > you're not getting truncation, but data corruption, as that's what > > > appending a number of null bytes is. thers is _no_ standard that permits > > > this without an interim system crash, fsync or not. > > > > Actually, without an fsync ***anything*** goes. In particular, if you > > append to a file, and the system allocates a new block, it's fair game > > for the file system to attach a block to the disk, but mark the block > > the as uninitalized, so that reads to that block results in zeros. > > Userspace process generally DO NOT read raw blocks from disk. > It uses kernel's buffer space, so buffered data should be consistent > regardless of disk contents. > > Oswald is right, process completion (by exit() or interrupt by signal) > can only truncate data, but can not corrupt. Only system crash can > lead to data corruption.
Oswald, I got the same Mbsync error without any crash and/or reboot, after several monthes of normal run. Mbsync was invoked in a loop "while sleep 30 ; do timeout 15s mbsync -a -V ; done". Any concurrency with other mbsync process is completely ruled out. Error message was iether "mailformed journal entry" or "incomplete journal entry", I do not remember exactly. The broken journal file is 33 bytes length: % hd .mbsyncstate.journal 00000000 32 0a 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |2...............| 00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00000021 After deletion of this file Mbsync continued to run as usual. I use Mbsync is from "isync-1.2.1-2" Debian package (Linux, 32-bit). -- Eugene Berdnikov ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today.http://sdm.link/intel _______________________________________________ isync-devel mailing list isync-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/isync-devel
