diff options
| author | J. Bruce Fields <bfields@redhat.com> | 2021-08-20 17:02:04 -0400 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2021-08-26 15:32:10 -0400 |
| commit | f657f8eef3ff870552c9fd2839e0061046f44618 (patch) | |
| tree | 9313d3b1f40869fbba03a443df788da4799a404f /fs/nfsd | |
| parent | 7f024fcd5c97dc70bb9121c80407cf3cf9be7159 (diff) | |
nfs: don't atempt blocking locks on nfs reexports
NFS implements blocking locks by blocking inside its lock method. In
the reexport case, this blocks the nfs server thread, which could lead
to deadlocks since an nfs server thread might be required to unlock the
conflicting lock. It also causes a crash, since the nfs server thread
assumes it can free the lock when its lm_notify lock callback is called.
Ideal would be to make the nfs lock method return without blocking in
this case, but for now it works just not to attempt blocking locks. The
difference is just that the original client will have to poll (as it
does in the v4.0 case) instead of getting a callback when the lock's
available.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/nfsd')
| -rw-r--r-- | fs/nfsd/nfs4state.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 2bedc7839ec5..d0b2041c4d75 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6835,6 +6835,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, struct nfsd4_blocked_lock *nbl = NULL; struct file_lock *file_lock = NULL; struct file_lock *conflock = NULL; + struct super_block *sb; __be32 status = 0; int lkflg; int err; @@ -6856,6 +6857,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, dprintk("NFSD: nfsd4_lock: permission denied!\n"); return status; } + sb = cstate->current_fh.fh_dentry->d_sb; if (lock->lk_is_new) { if (nfsd4_has_session(cstate)) @@ -6904,7 +6906,8 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, fp = lock_stp->st_stid.sc_file; switch (lock->lk_type) { case NFS4_READW_LT: - if (nfsd4_has_session(cstate)) + if (nfsd4_has_session(cstate) && + !(sb->s_export_op->flags & EXPORT_OP_SYNC_LOCKS)) fl_flags |= FL_SLEEP; fallthrough; case NFS4_READ_LT: @@ -6916,7 +6919,8 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, fl_type = F_RDLCK; break; case NFS4_WRITEW_LT: - if (nfsd4_has_session(cstate)) + if (nfsd4_has_session(cstate) && + !(sb->s_export_op->flags & EXPORT_OP_SYNC_LOCKS)) fl_flags |= FL_SLEEP; fallthrough; case NFS4_WRITE_LT: |