nfsd_setattr() can kick off a CB_RECALL (via
notify_change() -> break_lease()) if a delegation is present. Before
returning NFS4ERR_DELAY, give the client holding that delegation a
chance to return it and then retry the nfsd_setattr() again, once.
Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=354
Signed-off-by: Chuck Lever <[email protected]>
---
fs/nfsd/nfs4proc.c | 27 ++++++++++++++++++++++++++-
fs/nfsd/nfs4state.c | 1 +
fs/nfsd/nfsd.h | 1 +
fs/nfsd/trace.h | 19 +++++++++++++++++++
4 files changed, 47 insertions(+), 1 deletion(-)
Hi-
Naive approach to the issue of clients attempting to use SETATTR
without first returning a delegation. I'm interested in testing
and suggestions for improving this mechanism.
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 3895eb52d2b1..b4cda7a7e958 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1136,13 +1136,29 @@ nfsd4_secinfo_no_name_release(union nfsd4_op_u *u)
exp_put(u->secinfo_no_name.sin_exp);
}
+/*
+ * A better approach would wait for the DELEGRETURN operation, and
+ * retry just as soon as it was done. Unfortunately for NFSv4.0,
+ * we have only the FH, and there isn't a good way to look up a
+ * struct nfs4_delegation given an FH.
+ *
+ * The timeout prevents deadlock if all nfsd threads happen to be
+ * tied up waiting for returning delegations.
+ */
+static void nfsd4_wait_for_delegreturn(struct svc_rqst *rqstp,
+ struct svc_fh *fhp)
+{
+ trace_nfsd_delegreturn_wait(rqstp, fhp);
+ msleep(NFSD_DELEGRETURN_TIMEOUT);
+}
+
static __be32
nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
union nfsd4_op_u *u)
{
struct nfsd4_setattr *setattr = &u->setattr;
__be32 status = nfs_ok;
- int err;
+ int err, tried;
if (setattr->sa_iattr.ia_valid & ATTR_SIZE) {
status = nfs4_preprocess_stateid_op(rqstp, cstate,
@@ -1173,8 +1189,17 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
&setattr->sa_label);
if (status)
goto out;
+
+ tried = 0;
+retry:
status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr,
0, (time64_t)0);
+ if (unlikely(status == nfserr_jukebox && !tried)) {
+ nfsd4_wait_for_delegreturn(rqstp, &cstate->current_fh);
+ tried++;
+ goto retry;
+ }
+
out:
fh_drop_write(&cstate->current_fh);
return status;
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 9a8b09afc173..30838149c7ab 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -341,6 +341,7 @@ void nfsd_lockd_shutdown(void);
#define NFSD_LAUNDROMAT_MINTIMEOUT 1 /* seconds */
#define NFSD_COURTESY_CLIENT_TIMEOUT (24 * 60 * 60) /* seconds */
+#define NFSD_DELEGRETURN_TIMEOUT (50) /* milliseconds */
/*
* The following attributes are currently not supported by the NFSv4 server:
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index a60ead3b227a..7cc9c6eb4f4e 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -443,6 +443,25 @@ DEFINE_NFSD_COPY_ERR_EVENT(clone_file_range_err);
#include "filecache.h"
#include "vfs.h"
+TRACE_EVENT(nfsd_delegreturn_wait,
+ TP_PROTO(
+ const struct svc_rqst *rqstp,
+ const struct svc_fh *fhp
+ ),
+ TP_ARGS(rqstp, fhp),
+ TP_STRUCT__entry(
+ __field(u32, xid)
+ __field(u32, fh_hash)
+ ),
+ TP_fast_assign(
+ __entry->xid = be32_to_cpu(rqstp->rq_xid);
+ __entry->fh_hash = knfsd_fh_hash(&fhp->fh_handle);
+ ),
+ TP_printk("xid=0x%08x fh_hash=0x%08x",
+ __entry->xid, __entry->fh_hash
+ )
+);
+
DECLARE_EVENT_CLASS(nfsd_stateid_class,
TP_PROTO(stateid_t *stp),
TP_ARGS(stp),