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nfscl: Enable detection of bad session slots

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To deal with broken session slots caused by the use of the
"soft" and/or "intr" mount options, nfsv4_sequencelookup()
has been modified to track the potentially broken session
slots (commit 40ada74ee1).  Then, when all session slots
are potentially broken, nfsv4_sequencelookup() does a
DeleteSession operation, so that the NFSv4.1/4.2 server will
reply NFSERR_BADSESSION to uses of the session.
The client will then recover by doing a CreateSession to
acquire a new session.

This patch adds the code that marks potentially bad
slots, so that the above semantics become functional.
It has been successfully tested against a FreeBSD
NFSv4.1/4.2 server, but does not work against a Linux 5.15
NFSv4.1/4.2 server. (The Linux 5.15 server creates
a new session with the same sessionid as the destroyed
one and, as such, keeps returning NFSERR_BADSESSION.
I believe this is a bug in the Linux server.)

However, this should not cause a regression and will
make "intr" mounts fairly usable against the NFSv4.1/4.2
servers where it works.

PR: 260011
MFC after:	2 weeks
This commit is contained in:
Rick Macklem 2022-07-10 13:33:19 -07:00
parent e0e8d0c8d6
commit 981ef32230
1 changed files with 44 additions and 9 deletions
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53
sys/fs/nfs/nfs_commonkrpc.c
View File

@ -925,10 +925,8 @@ newnfs_request(struct nfsrv_descript *nd, struct nfsmount *nmp,
} else if (stat == RPC_PROGVERSMISMATCH) {
NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
error = EPROTONOSUPPORT;
} else if (stat == RPC_INTR) {
error = EINTR;
} else if (stat == RPC_CANTSEND || stat == RPC_CANTRECV ||
stat == RPC_SYSTEMERROR) {
stat == RPC_SYSTEMERROR || stat == RPC_INTR) {
/* Check for a session slot that needs to be free'd. */
if ((nd->nd_flag & (ND_NFSV41 | ND_HASSLOTID)) ==
(ND_NFSV41 | ND_HASSLOTID) && nmp != NULL &&
@ -951,12 +949,17 @@ newnfs_request(struct nfsrv_descript *nd, struct nfsmount *nmp,
*/
mtx_lock(&sep->nfsess_mtx);
sep->nfsess_slotseq[nd->nd_slotid] += 10;
sep->nfsess_badslots |= (0x1ULL << nd->nd_slotid);
mtx_unlock(&sep->nfsess_mtx);
/* And free the slot. */
nfsv4_freeslot(sep, nd->nd_slotid, false);
}
NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
error = ENXIO;
if (stat == RPC_INTR)
error = EINTR;
else {
NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
error = ENXIO;
}
} else {
NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
error = EACCES;
@ -1019,8 +1022,16 @@ newnfs_request(struct nfsrv_descript *nd, struct nfsmount *nmp,
* If the first op is Sequence, free up the slot.
*/
if ((nmp != NULL && i == NFSV4OP_SEQUENCE && j != 0) ||
(clp != NULL && i == NFSV4OP_CBSEQUENCE && j != 0))
(clp != NULL && i == NFSV4OP_CBSEQUENCE && j != 0)) {
NFSCL_DEBUG(1, "failed seq=%d\n", j);
if (sep != NULL && i == NFSV4OP_SEQUENCE &&
j == NFSERR_SEQMISORDERED) {
mtx_lock(&sep->nfsess_mtx);
sep->nfsess_badslots |=
(0x1ULL << nd->nd_slotid);
mtx_unlock(&sep->nfsess_mtx);
}
}
if (((nmp != NULL && i == NFSV4OP_SEQUENCE && j == 0) ||
(clp != NULL && i == NFSV4OP_CBSEQUENCE &&
j == 0)) && sep != NULL) {
@ -1039,11 +1050,35 @@ newnfs_request(struct nfsrv_descript *nd, struct nfsmount *nmp,
retseq = fxdr_unsigned(uint32_t, *tl++);
slot = fxdr_unsigned(int, *tl++);
if ((nd->nd_flag & ND_HASSLOTID) != 0) {
if (slot != nd->nd_slotid) {
if (slot >= NFSV4_SLOTS ||
(i == NFSV4OP_CBSEQUENCE &&
slot >= NFSV4_CBSLOTS)) {
printf("newnfs_request:"
" Wrong session "
"slot=%d\n", slot);
" Bogus slot\n");
slot = nd->nd_slotid;
} else if (slot !=
nd->nd_slotid) {
printf("newnfs_request:"
" Wrong session "
"srvslot=%d "
"slot=%d\n", slot,
nd->nd_slotid);
if (i == NFSV4OP_SEQUENCE) {
/*
* Mark both slots as
* bad, because we do
* not know if the
* server has advanced
* the sequence# for
* either of them.
*/
sep->nfsess_badslots |=
(0x1ULL << slot);
sep->nfsess_badslots |=
(0x1ULL <<
nd->nd_slotid);
}
slot = nd->nd_slotid;
}
} else if (slot != 0) {
printf("newnfs_request: Bad "