From 89318a02fe1c19aac6d85a17c45800544bd3cbe0 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Sun, 6 Sep 2026 14:41:41 -0400 Subject: [PATCH] NFSD: return NFS4ERR_EXIST for a guarded OPEN of a non-regular object Commit db8b567ffa98 ("nfsd: (almost) always open file in nfsd4_create_file()") moved the regular-file type check ahead of the createmode logic. A GUARDED4, EXCLUSIVE4, or EXCLUSIVE4_1 OPEN that finds a directory or symbolic link under the requested name now fails with NFS4ERR_ISDIR or NFS4ERR_SYMLINK instead of NFS4ERR_EXIST. RFC 8881 Section 18.16.3 requires NFS4ERR_EXIST when a guarded create finds any object under that name, or when an exclusive create's verifier does not match. The type-specific errors in Section 18.16.4 apply to opening an existing file, which only UNCHECKED4 does. Fixes: db8b567ffa98 ("nfsd: (almost) always open file in nfsd4_create_file()") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260906184141.3453309-1-cel@kernel.org Signed-off-by: Chuck Lever --- fs/nfsd/nfs4proc.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index bb74eef43938..3a82af381a8d 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -430,7 +430,17 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp, oflags, open->op_iattr.ia_mode); if (IS_ERR(open->op_filp)) { - status = nfserrno(PTR_ERR(open->op_filp)); + int hosterr = PTR_ERR(open->op_filp); + + if (open->op_createmode != NFS4_CREATE_UNCHECKED) { + switch (hosterr) { + case -EISDIR: + case -ELOOP: + case -EFTYPE: + hosterr = -EEXIST; + } + } + status = nfserrno(hosterr); open->op_filp = NULL; if (status == nfserr_noent && create_status) status = create_status;