nfsd: fix nfsd4_deleg_getattr_conflict in presence of third party lease

It is not safe to dereference fl->c.flc_owner without first confirming
fl->fl_lmops is the expected manager.  nfsd4_deleg_getattr_conflict()
tests fl_lmops but largely ignores the result and assumes that flc_owner
is an nfs4_delegation anyway.  This is wrong.

With this patch we restore the "!= &nfsd_lease_mng_ops" case to behave
as it did before the change mentioned below.  This is the same as the
current code, but without any reference to a possible delegation.

Fixes: c5967721e1 ("NFSD: handle GETATTR conflict with write delegation")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
NeilBrown 2024-08-29 09:06:28 +10:00 committed by Chuck Lever
parent 7e8ae8486e
commit 40927f3d09

View File

@ -8859,7 +8859,15 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
*/
if (type == F_RDLCK)
break;
goto break_lease;
nfsd_stats_wdeleg_getattr_inc(nn);
spin_unlock(&ctx->flc_lock);
status = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ));
if (status != nfserr_jukebox ||
!nfsd_wait_for_delegreturn(rqstp, inode))
return status;
return 0;
}
if (type == F_WRLCK) {
struct nfs4_delegation *dp = fl->c.flc_owner;
@ -8868,7 +8876,6 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
spin_unlock(&ctx->flc_lock);
return 0;
}
break_lease:
nfsd_stats_wdeleg_getattr_inc(nn);
dp = fl->c.flc_owner;
refcount_inc(&dp->dl_stid.sc_count);