2023-05-11 21:55:58

by Dai Ngo

[permalink] [raw]
Subject: [PATCH 2/4] NFSD: enable support for write delegation

This patch grants write delegation for OPEN with NFS4_SHARE_ACCESS_WRITE
if there is no conflict with other OPENs.

Write delegation conflict with another OPEN, REMOVE, RENAME and SETATTR
are handled the same as read delegation using notify_change,
try_break_deleg.

Signed-off-by: Dai Ngo <[email protected]>
---
fs/nfsd/nfs4state.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 6e61fa3acaf1..09a9e16407f9 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1144,7 +1144,7 @@ static void block_delegations(struct knfsd_fh *fh)

static struct nfs4_delegation *
alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
- struct nfs4_clnt_odstate *odstate)
+ struct nfs4_clnt_odstate *odstate, u32 dl_type)
{
struct nfs4_delegation *dp;
long n;
@@ -1170,7 +1170,7 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
INIT_LIST_HEAD(&dp->dl_recall_lru);
dp->dl_clnt_odstate = odstate;
get_clnt_odstate(odstate);
- dp->dl_type = NFS4_OPEN_DELEGATE_READ;
+ dp->dl_type = dl_type;
dp->dl_retries = 1;
dp->dl_recalled = false;
nfsd4_init_cb(&dp->dl_recall, dp->dl_stid.sc_client,
@@ -5451,6 +5451,7 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
struct nfs4_delegation *dp;
struct nfsd_file *nf;
struct file_lock *fl;
+ u32 deleg;

/*
* The fi_had_conflict and nfs_get_existing_delegation checks
@@ -5460,7 +5461,13 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
if (fp->fi_had_conflict)
return ERR_PTR(-EAGAIN);

- nf = find_readable_file(fp);
+ if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
+ nf = find_writeable_file(fp);
+ deleg = NFS4_OPEN_DELEGATE_WRITE;
+ } else {
+ nf = find_readable_file(fp);
+ deleg = NFS4_OPEN_DELEGATE_READ;
+ }
if (!nf) {
/*
* We probably could attempt another open and get a read
@@ -5491,11 +5498,11 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
return ERR_PTR(status);

status = -ENOMEM;
- dp = alloc_init_deleg(clp, fp, odstate);
+ dp = alloc_init_deleg(clp, fp, odstate, deleg);
if (!dp)
goto out_delegees;

- fl = nfs4_alloc_init_lease(dp, NFS4_OPEN_DELEGATE_READ);
+ fl = nfs4_alloc_init_lease(dp, deleg);
if (!fl)
goto out_clnt_odstate;

@@ -5583,6 +5590,7 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
struct svc_fh *parent = NULL;
int cb_up;
int status = 0;
+ u32 wdeleg = false;

cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
open->op_recall = 0;
@@ -5590,8 +5598,6 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
case NFS4_OPEN_CLAIM_PREVIOUS:
if (!cb_up)
open->op_recall = 1;
- if (open->op_delegate_type != NFS4_OPEN_DELEGATE_READ)
- goto out_no_deleg;
break;
case NFS4_OPEN_CLAIM_NULL:
parent = currentfh;
@@ -5617,7 +5623,9 @@ 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));

trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
- open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
+ wdeleg = open->op_share_access & NFS4_SHARE_ACCESS_WRITE;
+ open->op_delegate_type = wdeleg ?
+ NFS4_OPEN_DELEGATE_WRITE : NFS4_OPEN_DELEGATE_READ;
nfs4_put_stid(&dp->dl_stid);
return;
out_no_deleg:
--
2.9.5