cd /.zfs/snapshot hangs (tmux put to uninterruptible sleep)

[Matthew Seaman]

On 10/25/15 12:21, Niklaas Baudet von Gersdorff wrote:
> On 25/10/15 13:14, Matthew Seaman wrote:
>> Please do go ahead and reset your system.  Just realizing it's happening
>> to other people than me is sufficient incentive.
> 
> OK. Thanks a lot for your help!
> 
>> PS.  If you need to access one of the troublesome snapshots, use 'zfs
>> clone' -- it seems to avoid the various pitfalls.
> 
> OK. Great.
> 

Hmmm... I can't reproduce the problematic effect.  I set up a zfs with
snapshots like so:

# zfs list -t all -r tank/.......1
NAME
                    USED  AVAIL  REFER  MOUNTPOINT
tank/.......1
                     19K   769G    19K  /.......1
tank/.......1 at ....3.........4.........5.........6.........7.........8........
                 0      -    19K  -
tank/.......1 at ....3.........4.........5.........6.........7.........8.........
                0      -    19K  -
tank/.......1 at ....3.........4.........5.........6.........7.........8.........9.........0
     0      -    19K  -

where the contents of the ZFS were:

# find /.......1
/.......1
/.......1/aaa
/.......1/aaa/bbb
/.......1/aaa/bbb/ccc

Sorry about the funky filenames -- they're just for counting the
characters in the automount path for the snapshot.  The result is like
so (if you can make it out despite the line wrapping my mail client
wants to add):

# find /.......1/.zfs/snapshot
/.......1/.zfs/snapshot
find:
/.......1/.zfs/snapshot/....3.........4.........5.........6.........7.........8.........:
File name too long
/.......1/.zfs/snapshot/....3.........4.........5.........6.........7.........8........
/.......1/.zfs/snapshot/....3.........4.........5.........6.........7.........8......../aaa
/.......1/.zfs/snapshot/....3.........4.........5.........6.........7.........8......../aaa/bbb
/.......1/.zfs/snapshot/....3.........4.........5.........6.........7.........8......../aaa/bbb/ccc
find:
/.......1/.zfs/snapshot/....3.........4.........5.........6.........7.........8.........9.........0:
File name too long

# cd
/.......1/.zfs/snapshot/....3.........4.........5.........6.........7.........8.........9.........0/aaa/bbb

/.......1/.zfs/snapshot/....3.........4.........5.........6.........7.........8.........9.........0/aaa/bbb:
File name too long.


ie.  a mounted path length of 88 characters is OK, but 89 or 100
characters gets the 'name too long' error.  However, I can't detect any
problems after that.  No processes stuck trying to do IO.  So I guess
that whatever the problem was, it has been fixed in 10.2-RELEASE

	Cheers,

	Matthew


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