Apparently in my haste, forgot to include any information in my email. This is also in the URL to the gist of my test script:
btrfs v3.17 Linux 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt4-3 (2015-02-03) x86_64 GNU/Linux # mount: /dev/loop2 mounted on /tmp/tmp.FkcW7fRde7. # Showing mount: # /tmp/tmp.1fbwCCdeNM on /tmp/tmp.FkcW7fRde7 type btrfs (rw,noatime,space_cache) # Create subvolume '/tmp/tmp.FkcW7fRde7/subvol' # mkdir: created directory ‘/tmp/tmp.FkcW7fRde7/snapshots’ # mkdir: created directory ‘/tmp/tmp.FkcW7fRde7/empty_dir’ # Create a readonly snapshot of '/tmp/tmp.FkcW7fRde7' in '/tmp/tmp.FkcW7fRde7/snapshots/1' # Testing that the subvol dir has stable atime on original parent FS: # Testing that '/tmp/tmp.FkcW7fRde7/subvol' has repeatable atime of # 2015-03-06T11:09:40+1100... # 1: 2015-03-06T11:09:40+1100 # 2: 2015-03-06T11:09:40+1100 # PASS /tmp/tmp.FkcW7fRde7/subvol atime is stable :) # Testing that a normal empty dir has stable atime on the snapshot: # Testing that '/tmp/tmp.FkcW7fRde7/snapshots/1/empty_dir' has repeatable atime of # 2015-03-06T11:09:40+1100... # 1: 2015-03-06T11:09:40+1100 # 2: 2015-03-06T11:09:40+1100 # PASS /tmp/tmp.FkcW7fRde7/snapshots/1/empty_dir atime is stable :) # Testing that the subvol dir has stable atime on snapshot of parent FS: # Testing that '/tmp/tmp.FkcW7fRde7/snapshots/1/subvol' has repeatable atime of # 2015-03-06T11:09:48+1100... # 1: 2015-03-06T11:09:50+1100 # 2: 2015-03-06T11:09:52+1100 # FAIL /tmp/tmp.FkcW7fRde7/snapshots/1/subvol atime is unstable :( # './btrfs-atime-bug.sh nocleanup' not specified so cleaning up our mess: # umount: /tmp/tmp.FkcW7fRde7 unmounted # rmdir: removing directory, ‘/tmp/tmp.FkcW7fRde7’ # removed ‘/tmp/tmp.1fbwCCdeNM’ On 6 March 2015 at 11:29, Paul Harvey <csir...@gmail.com> wrote: > Hi there, > > Apologies for not confirming on a much more recent kernel, if anyone > could please try my test script for me on a newer kernel that would be > very much appreciated. > > I'm working on reproducible builds, and part of this workflow involves > tar archiving parts of read-only btrfs snapshots. Problem is, some of > these tar archives are different from run to run when they capture an > empty directory that happened to be a subvol parent on the original > FS: the atimes on these empty dirs are always returning the current > time - which is not the case with an ordinary empty directory created > with mkdir; it's also not the same behaviour on the original FS (tar > archives are reproducible if we use the original FS rather than the > read-only snapshot). This all happens regardless of mounting noatime. > > Perhaps this verbiage is convoluted, I'm writing this in a hurry with > limited internet connectivity - I have a reproducible test case here > at https://gist.github.com/csirac2/c2b5b2b9d0193b3c08a8 > > Again, I understand this is a pretty old kernel and perhaps this is > fixed by now, I'll try a more recent kernel with more assertive bug > report next week if nobody has time to try out my test case. > > Cheers > > -- > Paul Harvey -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
