[Samba] Strange logs from smbd

[Andrew Bartlett]

On Thu, 2021-12-02 at 22:09 +0000, Rowland Penny via samba wrote:
> On Thu, 2021-12-02 at 22:01 +0000, spindles seven via samba wrote:
> > On 02 December 2021 18:17 Patrick Goetz wrote:
> > > This looks like a btrfs issue -- what makes you think it's a
> > > samba
> > > issue?
> > 
> > Because smbd is reporting the log, so it's probably in the
> > vfs_btrfs
> > module, which is part of the samba suite.
> 
> It might be smbd that is reporting the error, but it is coming from
> this block of code:
> 
> fd = open(p, O_RDONLY);
> if (fd == -1) {
> 	DBG_ERR("/proc open of %s failed: %s\n", p, strerror(errno));
> 	return map_nt_error_from_unix(errno);
> }
> 
> It looks to myself that Samba is trying to open a file, but the
> permissions on that file do not allow it.
> 
> Rowland

The /proc/self/fd files are magic, I'm not surprised there might be FS-
dependent issues.  Likewise the things done in btrfs are special, it
would not be a shock if the new VFS behaviours have bad interactions,
we can't test btrfs in selftest.

But to be clear, seeing this after an upgrade is not a total shock, the
VFS was almost completely rewritten and /proc/self/fd is a big part of
that rewrite. 

Andrew Bartlett
-- 
Andrew Bartlett (he/him)       https://samba.org/~abartlet/
Samba Team Member (since 2001) https://samba.org
Samba Team Lead, Catalyst IT   https://catalyst.net.nz/services/samba

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