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Wed, 5 Mar 2025 22:05:24 GMT Received: from pps.reinject (localhost [127.0.0.1]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 453rpbrshu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 05 Mar 2025 22:05:24 +0000 Received: from phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 525M5NRf030215; Wed, 5 Mar 2025 22:05:23 GMT Received: from ca-common-sca.us.oracle.com (ca-common-sca.us.oracle.com [10.132.20.202]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTP id 453rpbrsh1-2; Wed, 05 Mar 2025 22:05:23 +0000 From: Dai Ngo To: chuck.lever@oracle.com, jlayton@kernel.org, neilb@suse.de, okorniev@redhat.com, tom@talpey.com Cc: linux-nfs@vger.kernel.org, sagi@grimberg.me Subject: [PATCH V5 1/1] NFSD: Offer write delegation for OPEN with OPEN4_SHARE_ACCESS_WRITE Date: Wed, 5 Mar 2025 14:05:08 -0800 Message-Id: <1741212308-13521-2-git-send-email-dai.ngo@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1741212308-13521-1-git-send-email-dai.ngo@oracle.com> References: <1741212308-13521-1-git-send-email-dai.ngo@oracle.com> X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-05_09,2025-03-05_02,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 suspectscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 malwarescore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2502100000 definitions=main-2503050170 X-Proofpoint-GUID: SJlx2w2pBtn_6qCiPUfGUKkuoTgfY6PO X-Proofpoint-ORIG-GUID: SJlx2w2pBtn_6qCiPUfGUKkuoTgfY6PO Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: RFC8881, section 9.1.2 says: "In the case of READ, the server may perform the corresponding check on the access mode, or it may choose to allow READ for OPEN4_SHARE_ACCESS_WRITE, to accommodate clients whose WRITE implementation may unavoidably do reads (e.g., due to buffer constraints)." and in section 10.4.1: "Similarly, when closing a file opened for OPEN4_SHARE_ACCESS_WRITE/ OPEN4_SHARE_ACCESS_BOTH and if an OPEN_DELEGATE_WRITE delegation is in effect" This patch allow READ using write delegation stateid granted on OPENs with OPEN4_SHARE_ACCESS_WRITE only, to accommodate clients whose WRITE implementation may unavoidably do (e.g., due to buffer cache constraints). For write delegation granted for OPEN with OPEN4_SHARE_ACCESS_WRITE a new nfsd_file and a struct file are allocated to use for reads. The nfsd_file is freed when the file is closed by release_all_access. Suggested-by: Chuck Lever Signed-off-by: Dai Ngo Reviewed-by: Jeff Layton --- fs/nfsd/nfs4state.c | 76 ++++++++++++++++++++++++++++----------------- 1 file changed, 48 insertions(+), 28 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 0f97f2c62b3a..4c5338c50f0c 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -633,18 +633,6 @@ find_readable_file(struct nfs4_file *f) return ret; } -static struct nfsd_file * -find_rw_file(struct nfs4_file *f) -{ - struct nfsd_file *ret; - - spin_lock(&f->fi_lock); - ret = nfsd_file_get(f->fi_fds[O_RDWR]); - spin_unlock(&f->fi_lock); - - return ret; -} - struct nfsd_file * find_any_file(struct nfs4_file *f) { @@ -5987,14 +5975,19 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp, * "An OPEN_DELEGATE_WRITE delegation allows the client to handle, * on its own, all opens." * - * Furthermore the client can use a write delegation for most READ - * operations as well, so we require a O_RDWR file here. + * Furthermore, section 9.1.2 says: + * + * "In the case of READ, the server may perform the corresponding + * check on the access mode, or it may choose to allow READ for + * OPEN4_SHARE_ACCESS_WRITE, to accommodate clients whose WRITE + * implementation may unavoidably do reads (e.g., due to buffer + * cache constraints)." * - * Offer a write delegation in the case of a BOTH open, and ensure - * we get the O_RDWR descriptor. + * We choose to offer a write delegation for OPEN with the + * OPEN4_SHARE_ACCESS_WRITE access mode to accommodate such clients. */ - if ((open->op_share_access & NFS4_SHARE_ACCESS_BOTH) == NFS4_SHARE_ACCESS_BOTH) { - nf = find_rw_file(fp); + if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) { + nf = find_writeable_file(fp); dl_type = deleg_ts ? OPEN_DELEGATE_WRITE_ATTRS_DELEG : OPEN_DELEGATE_WRITE; } @@ -6116,7 +6109,7 @@ static bool nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh, struct kstat *stat) { - struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file); + struct nfsd_file *nf = find_writeable_file(dp->dl_stid.sc_file); struct path path; int rc; @@ -6134,6 +6127,34 @@ nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh, return rc == 0; } +/* + * Add NFS4_SHARE_ACCESS_READ to the write delegation granted on OPEN + * with NFS4_SHARE_ACCESS_WRITE by allocating separate nfsd_file and + * struct file to be used for read with delegation stateid. + * + */ +static bool +nfsd4_add_rdaccess_to_wrdeleg(struct svc_rqst *rqstp, struct nfsd4_open *open, + struct svc_fh *fh, struct nfs4_ol_stateid *stp) +{ + struct nfs4_file *fp; + struct nfsd_file *nf = NULL; + + if ((open->op_share_access & NFS4_SHARE_ACCESS_BOTH) == + NFS4_SHARE_ACCESS_WRITE) { + if (nfsd_file_acquire_opened(rqstp, fh, NFSD_MAY_READ, NULL, &nf)) + return (false); + fp = stp->st_stid.sc_file; + spin_lock(&fp->fi_lock); + __nfs4_file_get_access(fp, NFS4_SHARE_ACCESS_READ); + set_access(NFS4_SHARE_ACCESS_READ, stp); + fp = stp->st_stid.sc_file; + fp->fi_fds[O_RDONLY] = nf; + spin_unlock(&fp->fi_lock); + } + return true; +} + /* * The Linux NFS server does not offer write delegations to NFSv4.0 * clients in order to avoid conflicts between write delegations and @@ -6159,8 +6180,9 @@ nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh, * open or lock state. */ static void -nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp, - struct svc_fh *currentfh) +nfs4_open_delegation(struct svc_rqst *rqstp, struct nfsd4_open *open, + struct nfs4_ol_stateid *stp, struct svc_fh *currentfh, + struct svc_fh *fh) { bool deleg_ts = open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS; struct nfs4_openowner *oo = openowner(stp->st_stateowner); @@ -6205,7 +6227,8 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp, memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid)); if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) { - if (!nfs4_delegation_stat(dp, currentfh, &stat)) { + if (!nfsd4_add_rdaccess_to_wrdeleg(rqstp, open, fh, stp) || + !nfs4_delegation_stat(dp, currentfh, &stat)) { nfs4_put_stid(&dp->dl_stid); destroy_delegation(dp); goto out_no_deleg; @@ -6361,7 +6384,8 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf * Attempt to hand out a delegation. No error return, because the * OPEN succeeds even if we fail. */ - nfs4_open_delegation(open, stp, &resp->cstate.current_fh); + nfs4_open_delegation(rqstp, open, stp, + &resp->cstate.current_fh, current_fh); /* * If there is an existing open stateid, it must be updated and @@ -7063,7 +7087,7 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate, return_revoked = true; if (typemask & SC_TYPE_DELEG) /* Always allow REVOKED for DELEG so we can - * retturn the appropriate error. + * return the appropriate error. */ statusmask |= SC_STATUS_REVOKED; @@ -7106,10 +7130,6 @@ nfs4_find_file(struct nfs4_stid *s, int flags) switch (s->sc_type) { case SC_TYPE_DELEG: - spin_lock(&s->sc_file->fi_lock); - ret = nfsd_file_get(s->sc_file->fi_deleg_file); - spin_unlock(&s->sc_file->fi_lock); - break; case SC_TYPE_OPEN: case SC_TYPE_LOCK: if (flags & RD_STATE)