[Gluster-devel] fstest for fuse mount gluster

Mon Apr 24 06:15:43 UTC 2017

On Mon, Apr 24, 2017 at 11:28 AM, Raghavendra Gowdappa <rgowdapp at redhat.com>
wrote:

> Its a known issue in DHT. Since DHT relies on some bits (S+T) in the stat
> for identifying that a file is being migrated by a rebalance process, it
> strips them off. But the problem is if the same bits are being used by
> application (as in this case). The fix (if we can come up with one) might
> require some time for validation as impact can be large. Possible solutions
> are:
>
> 1. Pranith pointed out that rebalance process always holds an inodelk
> during file migration. Probably we can leverage this information and decide
> whether to strip the flags or not.
> 2. There is also a linkto xattr stored on the data-file during migration.
> Instead of unconditionally striping Phase1(2) flags, lookup/stat codepaths
> can check for the presence of this xattr too and strip the flags only if it
> is present. Note that with this solution application won't see the (S+T)
> bits in stat during rebalance.
>

Innocent question. If we have a linkto-xattr and the lock, do we need
anything more to detect that migration is in progress? I am wondering if we
can remove the reliance on S+T bits. Worst case we will have to store the
info on the xattr.

>
> regards,
> Raghavendra.
>
> ----- Original Message -----
> > From: "Pranith Kumar Karampuri" <pkarampu at redhat.com>
> > To: "qingwei wei" <tchengwee at gmail.com>
> > Cc: "Gluster Devel" <gluster-devel at gluster.org>, "Raghavendra Gowdappa"
> <rgowdapp at redhat.com>, "Nithya Balachandran"
> > <nbalacha at redhat.com>
> > Sent: Monday, April 24, 2017 11:03:29 AM
> > Subject: Re: [Gluster-devel] fstest for fuse mount gluster
> >
> > This is a bug in dht it seems like. It is stripping PHASE1 flags
> > unconditionally.
> >
> > (gdb)
> > 1212                    DHT_STRIP_PHASE1_FLAGS (&local->stbuf);
> > (gdb) p local->stbuf.ia_prot
> > $18 = {
> >   suid = 1 '\001',
> >   sgid = 1 '\001', <-------
> >   sticky = 1 '\001', <-------
> > .........
> > }
> > (gdb) n
> > 1213                    dht_set_fixed_dir_stat (&local->postparent);
> > (gdb) p local->stbuf.ia_prot
> > $19 = {
> >   suid = 1 '\001',
> >   sgid = 0 '\000', <-------
> >   sticky = 0 '\000', <-------
> > ...
> >
> > This is leading to 7777-->4777
> >
> > Will update bug with same info
> >
> >
> > On Thu, Apr 20, 2017 at 8:58 PM, qingwei wei <tchengwee at gmail.com>
> wrote:
> >
> > > Hi,
> > >
> > > Posted this in gluster-user mailing list but got no response so far,
> so i
> > > post in gluster-devel.
> > >
> > > I found this test suite (https://github.com/Hnasar/pjdfstest) for me
> to
> > > test fuse mount gluster and there is some reported issue from the
> test. One
> > > of the error is as follow.
> > >
> > > When i chmod 7777 to a file in fuse mounted gluster volume. the return
> > > stat value for the file is not 7777 instead of 4777.
> > >
> > > root at ubuntu16d:/mnt/g310mp# touch test
> > > root at ubuntu16d:/mnt/g310mp# chmod 7777 test
> > > root at ubuntu16d:/mnt/g310mp# stat test
> > >   File: 'test'
> > >   Size: 0               Blocks: 0          IO Block: 131072 regular
> empty
> > > file
> > > Device: 29h/41d Inode: 9618589997017543511  Links: 1
> > > Access: (4777/-rwsrwxrwx)  Uid: (    0/    root)   Gid: (    0/
> root)
> > > Access: 2017-11-30 14:21:23.374871207 +0800
> > > Modify: 2017-11-30 14:21:16.974871000 +0800
> > > Change: 2017-11-30 14:21:23.374871207 +0800
> > >  Birth: -
> > >
> > > Performing this operation in normal ext4 system produce correct result.
> > >
> > > root at ubuntu16d:/mnt/g310mp# touch ~/testfile
> > > root at ubuntu16d:/mnt/g310mp# chmod 7777 ~/testfile
> > > root at ubuntu16d:/mnt/g310mp# stat ~/testfile
> > >   File: '/home/ubuntu/testfile'
> > >   Size: 0               Blocks: 0          IO Block: 4096   regular
> empty
> > > file
> > > Device: fc00h/64512d    Inode: 662649      Links: 1
> > > Access: (7777/-rwsrwsrwt)  Uid: (    0/    root)   Gid: (    0/
> root)
> > > Access: 2017-11-30 14:23:00.518867795 +0800
> > > Modify: 2017-11-30 14:23:00.518867795 +0800
> > > Change: 2017-11-30 14:23:08.742867507 +0800
> > >  Birth: -
> > >
> > > Besides 7777, 3777 also an issue. The stat return is 0777.
> > >
> > > My OS is Ubuntu 16.04 and my gluster version is 3.10.1 and the it is a
> > > simple volume with default parameter.
> > >
> > > root at ubuntu16d:/mnt/g310mp# gluster volume info
> > >
> > > Volume Name: g310
> > > Type: Distribute
> > > Volume ID: 114666c6-4884-436a-81a8-2deb3c0923ba
> > > Status: Started
> > > Snapshot Count: 0
> > > Number of Bricks: 1
> > > Transport-type: tcp
> > > Bricks:
> > > Brick1: 192.168.36.130:/mnt/g310brick
> > > Options Reconfigured:
> > > transport.address-family: inet
> > > nfs.disable: on
> > >
> > > for me, i seldom use those mode (3777 & 7777) but i cannot say for sure
> > > for others. So is this something i should be concerned about?
> > >
> > > Cw
> > >
> > > _______________________________________________
> > > Gluster-devel mailing list
> > > Gluster-devel at gluster.org
> > > http://lists.gluster.org/mailman/listinfo/gluster-devel
> > >
> >
> >
> >
> > --
> > Pranith
> >
>

-- 
Pranith
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