afs: Fix dynamic root lookup DNS check

In the afs dynamic root directory, the ->lookup() function does a DNS check
on the cell being asked for and if the DNS upcall reports an error it will
report an error back to userspace (typically ENOENT).

However, if a failed DNS upcall returns a new-style result, it will return
a valid result, with the status field set appropriately to indicate the
type of failure - and in that case, dns_query() doesn't return an error and
we let stat() complete with no error - which can cause confusion in
userspace as subsequent calls that trigger d_automount then fail with
ENOENT.

Fix this by checking the status result from a valid dns_query() and
returning an error if it indicates a failure.

Fixes: bbb4c4323a4d ("dns: Allow the dns resolver to retrieve a server set")
Reported-by: Markus Suvanto <[email protected]>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=216637
Signed-off-by: David Howells <[email protected]>
Tested-by: Markus Suvanto <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

0 files changed, 0 insertions, 0 deletions