In order to support write delegations with O_WRONLY opens, we need to
allow the clients to read using the write delegation stateid (Per RFC
8881 section 9.1.2. Use of the Stateid and Locking).
Hence, we check for NFS4_SHARE_ACCESS_WRITE set in open request, and
in case the share access flag does not set NFS4_SHARE_ACCESS_READ as
well, we'll open the file locally with O_RDWR in order to allow the
client to use the write delegation stateid when issuing a read in case
it may choose to.
Plus, find_rw_file singular call-site is now removed, remove it altogether.
Note: reads using special stateids that conflict with pending write
delegations are undetected, and will be covered in a follow on patch.
Signed-off-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
---
fs/nfsd/nfs4proc.c | 18 +++++++++++++++++-
fs/nfsd/nfs4state.c | 42 ++++++++++++++++++++----------------------
fs/nfsd/xdr4.h | 2 ++
3 files changed, 39 insertions(+), 23 deletions(-)
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 7b70309ad8fb..041bcc3ab5d7 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -979,8 +979,22 @@ nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
/* check stateid */
status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
&read->rd_stateid, RD_STATE,
- &read->rd_nf, NULL);
+ &read->rd_nf, &read->rd_wd_stid);
+ /*
+ * rd_wd_stid is needed for nfsd4_encode_read to allow write
+ * delegation stateid used for read. Its refcount is decremented
+ * by nfsd4_read_release when read is done.
+ */
+ if (!status) {
+ if (read->rd_wd_stid &&
+ (read->rd_wd_stid->sc_type != SC_TYPE_DELEG ||
+ delegstateid(read->rd_wd_stid)->dl_type !=
+ NFS4_OPEN_DELEGATE_WRITE)) {
+ nfs4_put_stid(read->rd_wd_stid);
+ read->rd_wd_stid = NULL;
+ }
+ }
read->rd_rqstp = rqstp;
read->rd_fhp = &cstate->current_fh;
return status;
@@ -990,6 +1004,8 @@ nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
static void
nfsd4_read_release(union nfsd4_op_u *u)
{
+ if (u->read.rd_wd_stid)
+ nfs4_put_stid(u->read.rd_wd_stid);
if (u->read.rd_nf)
nfsd_file_put(u->read.rd_nf);
trace_nfsd_read_done(u->read.rd_rqstp, u->read.rd_fhp,
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 0645fccbf122..538b6e1127a2 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -639,18 +639,6 @@ 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)
{
@@ -5784,15 +5772,11 @@ 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.
- *
- * Offer a write delegation in the case of a BOTH open, and ensure
- * we get the O_RDWR descriptor.
+ * Offer a write delegation for WRITE or BOTH access
*/
- 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) {
dl_type = NFS4_OPEN_DELEGATE_WRITE;
+ nf = find_writeable_file(fp);
}
/*
@@ -5934,8 +5918,8 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
* 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 nfs4_delegation *dp;
struct nfs4_openowner *oo = openowner(stp->st_stateowner);
@@ -5994,6 +5978,20 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
dp->dl_cb_fattr.ncf_initial_cinfo =
nfsd4_change_attribute(&stat, d_inode(currentfh->fh_dentry));
+ if ((open->op_share_access & NFS4_SHARE_ACCESS_BOTH) != NFS4_SHARE_ACCESS_BOTH) {
