git: 5e1753891a09 - stable/13 - nfsd: fix session slot handling for failed callbacks
Rick Macklem
rmacklem at FreeBSD.org
Mon May 10 15:02:44 UTC 2021
The branch stable/13 has been updated by rmacklem:
URL: https://cgit.FreeBSD.org/src/commit/?id=5e1753891a09df5411627e87bad7dc66226607d7
commit 5e1753891a09df5411627e87bad7dc66226607d7
Author: Rick Macklem <rmacklem at FreeBSD.org>
AuthorDate: 2021-04-23 22:24:47 +0000
Commit: Rick Macklem <rmacklem at FreeBSD.org>
CommitDate: 2021-05-10 14:57:51 +0000
nfsd: fix session slot handling for failed callbacks
When the NFSv4.1/4.2 server does a callback to a client
on the back channel, it will use a session slot in the
back channel session. If the back channel has failed,
the callback will fail and, without this patch, the
session slot will not be released.
As more callbacks are attempted, all session slots
can become busy and then the nfsd thread gets stuck
waiting for a back channel session slot.
This patch frees the session slot upon callback
failure to avoid this problem.
Without this patch, the problem can be avoided by leaving
delegations disabled in the NFS server.
(cherry picked from commit 4281bfec36285e2212f41568459c077bf4dbd91c)
---
sys/fs/nfsserver/nfs_nfsdstate.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/sys/fs/nfsserver/nfs_nfsdstate.c b/sys/fs/nfsserver/nfs_nfsdstate.c
index 60647ab288d8..430f09844b83 100644
--- a/sys/fs/nfsserver/nfs_nfsdstate.c
+++ b/sys/fs/nfsserver/nfs_nfsdstate.c
@@ -166,7 +166,8 @@ static int nfsrv_docallback(struct nfsclient *clp, int procnum,
nfsv4stateid_t *stateidp, int trunc, fhandle_t *fhp,
struct nfsvattr *nap, nfsattrbit_t *attrbitp, int laytype, NFSPROC_T *p);
static int nfsrv_cbcallargs(struct nfsrv_descript *nd, struct nfsclient *clp,
- uint32_t callback, int op, const char *optag, struct nfsdsession **sepp);
+ uint32_t callback, int op, const char *optag, struct nfsdsession **sepp,
+ int *slotposp);
static u_int32_t nfsrv_nextclientindex(void);
static u_int32_t nfsrv_nextstateindex(struct nfsclient *clp);
static void nfsrv_markstable(struct nfsclient *clp);
@@ -201,7 +202,7 @@ static void nfsrv_unlocklf(struct nfslockfile *lfp);
static struct nfsdsession *nfsrv_findsession(uint8_t *sessionid);
static int nfsrv_freesession(struct nfsdsession *sep, uint8_t *sessionid);
static int nfsv4_setcbsequence(struct nfsrv_descript *nd, struct nfsclient *clp,
- int dont_replycache, struct nfsdsession **sepp);
+ int dont_replycache, struct nfsdsession **sepp, int *slotposp);
static int nfsv4_getcbsession(struct nfsclient *clp, struct nfsdsession **sepp);
static int nfsrv_addlayout(struct nfsrv_descript *nd, struct nfslayout **lypp,
nfsv4stateid_t *stateidp, char *layp, int *layoutlenp, NFSPROC_T *p);
@@ -4434,7 +4435,7 @@ nfsrv_docallback(struct nfsclient *clp, int procnum, nfsv4stateid_t *stateidp,
u_int32_t *tl;
struct nfsrv_descript *nd;
struct ucred *cred;
- int error = 0;
+ int error = 0, slotpos;
u_int32_t callback;
struct nfsdsession *sep = NULL;
uint64_t tval;
@@ -4492,7 +4493,7 @@ nfsrv_docallback(struct nfsclient *clp, int procnum, nfsv4stateid_t *stateidp,
if (procnum == NFSV4OP_CBGETATTR) {
nd->nd_procnum = NFSV4PROC_CBCOMPOUND;
error = nfsrv_cbcallargs(nd, clp, callback, NFSV4OP_CBGETATTR,
- "CB Getattr", &sep);
+ "CB Getattr", &sep, &slotpos);
if (error != 0) {
m_freem(nd->nd_mreq);
goto errout;
@@ -4502,7 +4503,7 @@ nfsrv_docallback(struct nfsclient *clp, int procnum, nfsv4stateid_t *stateidp,
} else if (procnum == NFSV4OP_CBRECALL) {
nd->nd_procnum = NFSV4PROC_CBCOMPOUND;
error = nfsrv_cbcallargs(nd, clp, callback, NFSV4OP_CBRECALL,
- "CB Recall", &sep);
+ "CB Recall", &sep, &slotpos);
if (error != 0) {
m_freem(nd->nd_mreq);
goto errout;
@@ -4521,7 +4522,7 @@ nfsrv_docallback(struct nfsclient *clp, int procnum, nfsv4stateid_t *stateidp,
NFSD_DEBUG(4, "docallback layout recall\n");
nd->nd_procnum = NFSV4PROC_CBCOMPOUND;
error = nfsrv_cbcallargs(nd, clp, callback,
- NFSV4OP_CBLAYOUTRECALL, "CB Reclayout", &sep);
+ NFSV4OP_CBLAYOUTRECALL, "CB Reclayout", &sep, &slotpos);
NFSD_DEBUG(4, "aft cbcallargs=%d\n", error);
if (error != 0) {
m_freem(nd->nd_mreq);
@@ -4570,6 +4571,8 @@ nfsrv_docallback(struct nfsclient *clp, int procnum, nfsv4stateid_t *stateidp,
if (clp->lc_req.nr_client == NULL) {
if ((clp->lc_flags & LCL_NFSV41) != 0) {
error = ECONNREFUSED;
+ if (procnum != NFSV4PROC_CBNULL)
+ nfsv4_freeslot(&sep->sess_cbsess, slotpos);
nfsrv_freesession(sep, NULL);
} else if (nd->nd_procnum == NFSV4PROC_CBNULL)
error = newnfs_connect(NULL, &clp->lc_req, cred,
@@ -4601,6 +4604,8 @@ nfsrv_docallback(struct nfsclient *clp, int procnum, nfsv4stateid_t *stateidp,
error = ECONNREFUSED;
}
NFSD_DEBUG(4, "aft newnfs_request=%d\n", error);
+ if (error != 0 && procnum != NFSV4PROC_CBNULL)
+ nfsv4_freeslot(&sep->sess_cbsess, slotpos);
nfsrv_freesession(sep, NULL);
} else
error = newnfs_request(nd, NULL, clp, &clp->lc_req,
@@ -4663,7 +4668,8 @@ errout:
*/
static int
nfsrv_cbcallargs(struct nfsrv_descript *nd, struct nfsclient *clp,
- uint32_t callback, int op, const char *optag, struct nfsdsession **sepp)
+ uint32_t callback, int op, const char *optag, struct nfsdsession **sepp,
+ int *slotposp)
{
uint32_t *tl;
int error, len;
@@ -4679,7 +4685,7 @@ nfsrv_cbcallargs(struct nfsrv_descript *nd, struct nfsclient *clp,
*tl++ = txdr_unsigned(callback);
*tl++ = txdr_unsigned(2);
*tl = txdr_unsigned(NFSV4OP_CBSEQUENCE);
- error = nfsv4_setcbsequence(nd, clp, 1, sepp);
+ error = nfsv4_setcbsequence(nd, clp, 1, sepp, slotposp);
if (error != 0)
return (error);
NFSM_BUILD(tl, u_int32_t *, NFSX_UNSIGNED);
@@ -6599,11 +6605,11 @@ nfsrv_teststateid(struct nfsrv_descript *nd, nfsv4stateid_t *stateidp,
*/
static int
nfsv4_setcbsequence(struct nfsrv_descript *nd, struct nfsclient *clp,
- int dont_replycache, struct nfsdsession **sepp)
+ int dont_replycache, struct nfsdsession **sepp, int *slotposp)
{
struct nfsdsession *sep;
uint32_t *tl, slotseq = 0;
- int maxslot, slotpos;
+ int maxslot;
uint8_t sessionid[NFSX_V4SESSIONID];
int error;
@@ -6611,7 +6617,7 @@ nfsv4_setcbsequence(struct nfsrv_descript *nd, struct nfsclient *clp,
if (error != 0)
return (error);
sep = *sepp;
- (void)nfsv4_sequencelookup(NULL, &sep->sess_cbsess, &slotpos, &maxslot,
+ (void)nfsv4_sequencelookup(NULL, &sep->sess_cbsess, slotposp, &maxslot,
&slotseq, sessionid);
KASSERT(maxslot >= 0, ("nfsv4_setcbsequence neg maxslot"));
@@ -6621,7 +6627,7 @@ nfsv4_setcbsequence(struct nfsrv_descript *nd, struct nfsclient *clp,
tl += NFSX_V4SESSIONID / NFSX_UNSIGNED;
nd->nd_slotseq = tl;
*tl++ = txdr_unsigned(slotseq);
- *tl++ = txdr_unsigned(slotpos);
+ *tl++ = txdr_unsigned(*slotposp);
*tl++ = txdr_unsigned(maxslot);
if (dont_replycache == 0)
*tl++ = newnfs_true;
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