[Gluster-users] Files losing permissions in GlusterFS 3.12

[Nithya Balachandran]

On Fri, 25 Jan 2019 at 20:51, Gudrun Mareike Amedick <
g.amedick at uni-luebeck.de> wrote:

> Hi all,
>
> we have a problem with a distributed dispersed volume (GlusterFS 3.12). We
> have files that lost their permissions or gained sticky bits. The files
> themselves seem to be okay.
>
> It looks like this:
>
> # ls -lah $file1
> ---------- 1 www-data www-data 45M Jan 12 07:01 $file1
>
> # ls -lah $file2
> -rw-rwS--T 1 $user $group 11K Jan  9 11:48 $file2
>
> # ls -lah $file3
> ---------T 1 $user $group 6.8M Jan 12 08:17 $file3
>
> These are linkto files (internal dht files) and should not be visible on
the mount point. Are they consistently visible like this or do they revert
to the proper permissions after some time?



> This is not what the permissions are supposed to look. They were 644 or
> 660 before. And they definitely had no sticky bits.
> The permissions on the bricks match what I see on client side. So I think
> the original permissions are lost without a chance to recover them, right?
>
>
> With some files with weird looking permissions (but not with all of them),
> I can do this:
> # ls -lah $path/$file4
> -rw-r--r-- 1 $user $group 6.0G Oct 11 09:34 $path/$file4
> ls -lah $path | grep $file4
> -rw-r-Sr-T  1 $user$group 6.0G Oct 11 09:34 $file4


> So, the permissions I see depend on how I'm querying them. The permissions
> on brick side agree with the ladder result, stat sees the former. I'm not
> sure how that works.
>
The S and T bits indicate that a file is being migrated. The difference
seems to be because of the way lookup versus readdirp handle this  - this
looks like a bug. Lookup will strip out the internal permissions set. I
don't think readdirp does. This is happening because a rebalance is in
progress.


> We know for at least a part of those files that they were okay at December
> 19th. We got the first reports of weird-looking permissions at January
> 12th. Between that, there was a rebalance running (January 7th to January
> 11th). During that rebalance, a node was offline for a longer period of time
> due to hardware issues. The output of "gluster volume heal $VOLUME info"
> shows no files though.
>
> For all files with broken permissions we found so far, the following lines
> are in the rebalance log:
>
> [2019-01-07 09:31:11.004802] I [MSGID: 109045]
> [dht-common.c:2456:dht_lookup_cbk] 0-$VOLUME-dht: linkfile not having link
> subvol for $file5
> [2019-01-07 09:31:11.262273] I [MSGID: 109069]
> [dht-common.c:1410:dht_lookup_unlink_of_false_linkto_cbk] 0-$VOLUME-dht:
> lookup_unlink returned with
> op_ret -> 0 and op-errno -> 0 for $file5
> [2019-01-07 09:31:11.266014] I [dht-rebalance.c:1570:dht_migrate_file]
> 0-$VOLUME-dht: $file5: attempting to move from $VOLUME-readdir-ahead-0 to
> $VOLUME-readdir-ahead-5
> [2019-01-07 09:31:11.278120] I [dht-rebalance.c:1570:dht_migrate_file]
> 0-$VOLUME-dht: $file5: attempting to move from $VOLUME-readdir-ahead-0 to
> $VOLUME-readdir-ahead-5
> [2019-01-07 09:31:11.732175] W [dht-rebalance.c:2159:dht_migrate_file]
> 0-$VOLUME-dht: $file5: failed to perform removexattr on
> $VOLUME-readdir-ahead-0
> (No data available)
> [2019-01-07 09:31:11.737319] W [MSGID: 109023]
> [dht-rebalance.c:2179:dht_migrate_file] 0-$VOLUME-dht: $file5: failed to do
> a stat on $VOLUME-readdir-
> ahead-0 [No such file or directory]
> [2019-01-07 09:31:11.744382] I [MSGID: 109022]
> [dht-rebalance.c:2218:dht_migrate_file] 0-$VOLUME-dht: completed migration
> of $file5 from subvolume
> $VOLUME-readdir-ahead-0 to $VOLUME-readdir-ahead-5
> [2019-01-07 09:31:11.744676] I [MSGID: 109022]
> [dht-rebalance.c:2218:dht_migrate_file] 0-$VOLUME-dht: completed migration
> of $file5 from subvolume
> $VOLUME-readdir-ahead-0 to $VOLUME-readdir-ahead-5
>
>
>
> I've searched the brick logs for $file5 with broken permissions and found
> this on all bricks from (I think) the subvolume $VOLUME-readdir-ahead-5:
>
> [2019-01-07 09:32:13.821545] I [MSGID: 113030] [posix.c:2171:posix_unlink]
> 0-$VOLUME-posix: open-fd-key-status: 0 for $file5
> [2019-01-07 09:32:13.821609] I [MSGID: 113031]
> [posix.c:2084:posix_skip_non_linkto_unlink] 0-posix: linkto_xattr status: 0
> for $file5
>
>
>
> Also, we noticed that many directories got their modification time
> updated. It was set to the rebalance date. Is that supposed to happen?
>
>
> We had parallel-readdir enabled during the rebalance. We disabled it since
> we had empty directories that couldn't be deleted. I was able to delete
> those dirs after that.
>

Was this disabled during the rebalance? parallel-readdirp changes the
volume graph for clients but not for the rebalance process causing it to
fail to find the linkto subvols.


>
> Also, we have directories who lost their GFID on some bricks. Again.


Is this the missing symlink problem that was reported earlier?

Regards,
Nithya

>
>

> What happened? Can we do something to fix this? And could that happen
> again?
>
> We want to upgrade to 4.1 soon. Is it safe to do that or could it make
> things worse?
>
> Kind regards
>
> Gudrun Amedick_______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> https://lists.gluster.org/mailman/listinfo/gluster-users
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