Re: Linux-next-20190823: x86_64/i386: prot_hsymlinks.c:325: Failed to run cmd: useradd hsym

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> On Mon, 2019-08-26 at 10:38 -0400, Jan Stancek wrote:
> > ----- Original Message -----
> > > Hi Jan and Cyril,
> > > 
> > > On Mon, 26 Aug 2019 at 16:35, Jan Stancek <jstancek@redhat.com>
> > > wrote:
> > > > 
> > > > 
> > > > ----- Original Message -----
> > > > > Hi!
> > > > > > Do you see this LTP prot_hsymlinks failure on linux next
> > > > > > 20190823 on
> > > > > > x86_64 and i386 devices?
> > > > > > 
> > > > > > test output log,
> > > > > > useradd: failure while writing changes to /etc/passwd
> > > > > > useradd: /home/hsym was created, but could not be removed
> > > > > 
> > > > > This looks like an unrelated problem, failure to write to
> > > > > /etc/passwd
> > > > > probably means that filesystem is full or some problem happend
> > > > > and how
> > > > > is remounted RO.
> > > > 
> > > > In Naresh' example, root is on NFS:
> > > >   root=/dev/nfs rw
> > > >  
> > > > nfsroot=10.66.16.123:/var/lib/lava/dispatcher/tmp/886412/extract-
> > > > nfsrootfs-tyuevoxm,tcp,hard,intr
> > > 
> > > Right !
> > > root is mounted on NFS.
> > > 
> > > > 10.66.16.123:/var/lib/lava/dispatcher/tmp/886412/extract-
> > > > nfsrootfs-tyuevoxm
> > > > on / type nfs
> > > > (rw,relatime,vers=2,rsize=4096,wsize=4096,namlen=255,hard,nolock,
> > > > proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=10.66.16.123,moun
> > > > tvers=1,mountproto=tcp,local_lock=all,addr=10.66.16.123)
> > > > devtmpfs on /dev type devtmpfs
> > > > (rw,relatime,size=3977640k,nr_inodes=994410,mode=755)
> > > > 
> 
> The only thing I can think of that might cause an EIO on NFSv2 would be
> this patch
> http://git.linux-nfs.org/?p=trondmy/linux-nfs.git;a=commitdiff;h=627d48e597ec5993c4abb3b81dc75e554a07c7c0
> assuming that a bind-related error is leaking through.
> 
> I'd suggest something like the following to fix it up:

No change with that patch,
but following one fixes it for me:

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 20b3717cd7ca..56cefa0ab804 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -590,7 +590,7 @@ static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
        }
 
        hdr->res.fattr   = &hdr->fattr;
-       hdr->res.count   = 0;
+       hdr->res.count   = count;
        hdr->res.eof     = 0;
        hdr->res.verf    = &hdr->verf;
        nfs_fattr_init(&hdr->fattr);

which is functionally revert of "NFS: Fix initialisation of I/O result struct in nfs_pgio_rpcsetup".

This hunk caught my eye, could res.eof == 0 explain those I/O errors?
                /* Emulate the eof flag, which isn't normally needed in NFSv2                                                                                 
                 * as it is guaranteed to always return the file attributes                                                                                   
                 */                                                                                                                                           
                if (hdr->args.offset + hdr->res.count >= hdr->res.fattr->size)                                                                                
                        hdr->res.eof = 1;