Re: [Gluster-devel] [Gluster-users] Fencing FOPs on data-split-brained files

[Anand Avati]

Ravi,

We should not mix up data and entry operation domains, if a file is in data split brain that should not stop a user from rename/link/unlink operations on the file.

Regarding your concern about complications while healing - we should change our "manual fixing" instructions to:

- go to backend, access through gfid path or normal path

- rmxattr the afr changelogs

- truncate the file to 0 bytes (like "> filename")

Accessing the path through gfid and truncating to 0 bytes addresses your concerns about hardlinks/renames.

Avati

On Wed, Nov 13, 2013 at 3:01 AM, Ravishankar N <address@hidden> wrote:

Hi,

Currenly in glusterfs, when there is a data splt-brain (only) on a file, we disallow the following operations from the mount-point by returning EIO to the application:
- Writes to the file (truncate, dd, echo, cp etc)
- Reads to the file (cat)
- Reading extended attributes (getfattr) [1]

However we do permit the following operations:
-creating hardlinks
-creating symlinks
-mv
-setattr
-chmod
-chown
--touch
-ls
-stat

While it makes sense to allow `ls` and `stat`, is it okay to  add checks in the FOPS to disallow the other operations? Allowing creation of links and changing file attributes only seems to complicate things before the admin can go to the backend bricks and resolve the splitbrain (by deleteing all but the healthy copy of the file including hardlinks). More so if the file is renamed before addressing the split-brain.
Please share your thoughs.

Thanks,
Ravi

[1] http://review.gluster.org/#/c/5988/
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