[tahoe-lafs-trac-stream] [tahoe-lafs] #1937: back up the content of a file even if the content changes without changing mtime

[tahoe-lafs]

#1937: back up the content of a file even if the content changes without changing
mtime
-------------------------+-------------------------------------------------
     Reporter:  zooko    |      Owner:
         Type:  defect   |     Status:  new
     Priority:  normal   |  Milestone:  undecided
    Component:  code     |    Version:  1.9.2
   Resolution:           |   Keywords:  tahoe-backup reliability
Launchpad Bug:           |  preservation
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Comment (by zooko):

 Replying to [comment:2 daira]:
 > If we use the approach of comment:1, then I suggest using a fixed G = 4s
 instead of trying to guess what the timestamp granularity is.

 +1

 >  Also, after the file has been uploaded we should check the mtime again,
 in case it was modified while we were reading it.
 >
 > Short of making a shadow copy on filesystems that support it, it's not
 possible to get a completely consistent snapshot of a filesystem that is
 being modified, using POSIX APIs.

 Hm, I think this is a separate issue. The problem that ''this'' ticket
 seeks to address is that different-contents-same-mtime can lead to data
 loss. The issue you raise in this comment is, I think, #427.

-- 
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1937#comment:3>
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