From e1df03e293a0b96707044d3f08f6985a5c45eedb Mon Sep 17 00:00:00 2001 From: Scott Mayhew Date: Mon, 3 Nov 2025 10:44:15 -0500 Subject: [PATCH] NFSv4: ensure the open stateid seqid doesn't go backwards [ Upstream commit 2e47c3cc64b44b0b06cd68c2801db92ff143f2b2 ] We have observed an NFSv4 client receiving a LOCK reply with a status of NFS4ERR_OLD_STATEID and subsequently retrying the LOCK request with an earlier seqid value in the stateid. As this was for a new lockowner, that would imply that nfs_set_open_stateid_locked() had updated the open stateid seqid with an earlier value. Looking at nfs_set_open_stateid_locked(), if the incoming seqid is out of sequence, the task will sleep on the state->waitq for up to 5 seconds. If the task waits for the full 5 seconds, then after finishing the wait it'll update the open stateid seqid with whatever value the incoming seqid has. If there are multiple waiters in this scenario, then the last one to perform said update may not be the one with the highest seqid. Add a check to ensure that the seqid can only be incremented, and add a tracepoint to indicate when old seqids are skipped. Signed-off-by: Scott Mayhew Reviewed-by: Benjamin Coddington Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- fs/nfs/nfs4proc.c | 13 +++++++++++-- fs/nfs/nfs4trace.h | 1 + 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 172ff213b50b..89f779f16f0d 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -1753,8 +1753,17 @@ static void nfs_set_open_stateid_locked(struct nfs4_state *state, if (nfs_stateid_is_sequential(state, stateid)) break; - if (status) - break; + if (status) { + if (nfs4_stateid_match_other(stateid, &state->open_stateid) && + !nfs4_stateid_is_newer(stateid, &state->open_stateid)) { + trace_nfs4_open_stateid_update_skip(state->inode, + stateid, status); + return; + } else { + break; + } + } + /* Rely on seqids for serialisation with NFSv4.0 */ if (!nfs4_has_session(NFS_SERVER(state->inode)->nfs_client)) break; diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h index 22c973316f0b..9a38a5d3bf51 100644 --- a/fs/nfs/nfs4trace.h +++ b/fs/nfs/nfs4trace.h @@ -1278,6 +1278,7 @@ DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_setattr); DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_delegreturn); DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_open_stateid_update); DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_open_stateid_update_wait); +DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_open_stateid_update_skip); DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_close_stateid_update_wait); DECLARE_EVENT_CLASS(nfs4_getattr_event,