[PATCH nfsd-fixes] nfsd: fix nfsd4_deleg_getattr_conflict in presence of third party lease
From: NeilBrown <hidden>
Date: 2024-08-28 23:06:36
Subsystem:
filesystems (vfs and infrastructure), kernel nfsd, sunrpc, and lockd servers, the rest · Maintainers:
Alexander Viro, Christian Brauner, Chuck Lever, Jeff Layton, Linus Torvalds
It is not safe to dereference fl->c.flc_owner without first confirming
fl->fl_lmops is the expected manager. nfsd4_deleg_getattr_conflict()
tests fl_lmops but largely ignores the result and assumes that flc_owner
is an nfs4_delegation anyway. This is wrong.
With this patch we restore the "!= &nfsd_lease_mng_ops" case to behave
as it did before the changed mentioned below. This the same as the
current code, but without any reference to a possible delegation.
Fixes: c5967721e106 ("NFSD: handle GETATTR conflict with write delegation")
Signed-off-by: NeilBrown <redacted>
---
fs/nfsd/nfs4state.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 07f2496850c4..f6a67ef27435 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c@@ -8859,7 +8859,15 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry, */ if (type == F_RDLCK) break; - goto break_lease; + + nfsd_stats_wdeleg_getattr_inc(nn); + spin_unlock(&ctx->flc_lock); + + status = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ)); + if (status != nfserr_jukebox || + !nfsd_wait_for_delegreturn(rqstp, inode)) + return status; + return 0; } if (type == F_WRLCK) { struct nfs4_delegation *dp = fl->c.flc_owner;
@@ -8868,7 +8876,6 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry, spin_unlock(&ctx->flc_lock); return 0; } -break_lease: nfsd_stats_wdeleg_getattr_inc(nn); dp = fl->c.flc_owner; refcount_inc(&dp->dl_stid.sc_count);
--
2.44.0