[PATCH v10 16/19] pnfs/flexfiles: enable localio for flexfiles I/O

Mike Snitzer
2024-06-30T16:38:04Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

If the DS is local to this client, then we should be able to use local
I/O to write the data.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
fs/nfs/flexfilelayout/flexfilelayout.c | 113 ++++++++++++++++++++--
fs/nfs/flexfilelayout/flexfilelayout.h | 2 +
fs/nfs/flexfilelayout/flexfilelayoutdev.c | 6 ++
3 files changed, 112 insertions(+), 9 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 58f20cebf0c6..8b9096ad0663 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -11,6 +11,7 @@
#include <linux/nfs_mount.h>
#include <linux/nfs_page.h>
#include <linux/module.h>
+#include <linux/file.h>
#include <linux/sched/mm.h>

#include <linux/sunrpc/metrics.h>
@@ -162,6 +163,52 @@ decode_name(struct xdr_stream *xdr, u32 *id)
return 0;
}

+static struct file *
+ff_local_open_fh(struct pnfs_layout_segment *lseg,
+ u32 ds_idx,
+ struct nfs_client *clp,
+ const struct cred *cred,
+ struct nfs_fh *fh,
+ fmode_t mode)
+{
+ struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx);
+ struct file *filp, *new, __rcu **pfile;
+
+ if (!nfs_server_is_local(clp))
+ return NULL;
+ if (mode & FMODE_WRITE) {
+ /*
+ * Always request read and write access since this corresponds
+ * to a rw layout.
+ */
+ mode |= FMODE_READ;
+ pfile = &mirror->rw_file;
+ } else
+ pfile = &mirror->ro_file;
+
+ new = NULL;
+ rcu_read_lock();
+ filp = rcu_dereference(*pfile);
+ if (!filp) {
+ rcu_read_unlock();
+ new = nfs_local_open_fh(clp, cred, fh, mode);
+ if (IS_ERR(new))
+ return NULL;
+ rcu_read_lock();
+ /* try to swap in the pointer */
+ filp = cmpxchg(pfile, NULL, new);
+ if (!filp) {
+ filp = new;
+ new = NULL;
+ }
+ }
+ filp = get_file_rcu(&filp);
+ rcu_read_unlock();
+ if (new)
+ fput(new);
+ return filp;
+}
+
static bool ff_mirror_match_fh(const struct nfs4_ff_layout_mirror *m1,
const struct nfs4_ff_layout_mirror *m2)
{
@@ -237,8 +284,15 @@ static struct nfs4_ff_layout_mirror *ff_layout_alloc_mirror(gfp_t gfp_flags)

static void ff_layout_free_mirror(struct nfs4_ff_layout_mirror *mirror)
{
+ struct file *filp;
const struct cred *cred;

+ filp = rcu_access_pointer(mirror->ro_file);
+ if (filp)
+ fput(filp);
+ filp = rcu_access_pointer(mirror->rw_file);
+ if (filp)
+ fput(filp);
ff_layout_remove_mirror(mirror);
kfree(mirror->fh_versions);
cred = rcu_access_pointer(mirror->ro_cred);
@@ -414,6 +468,7 @@ ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
struct nfs4_ff_layout_mirror *mirror;
struct cred *kcred;
const struct cred __rcu *cred;
+ const struct cred __rcu *old;
kuid_t uid;
kgid_t gid;
u32 ds_count, fh_count, id;
@@ -513,13 +568,26 @@ ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,

mirror = ff_layout_add_mirror(lh, fls->mirror_array[i]);
if (mirror != fls->mirror_array[i]) {
+ struct file *filp;
+
/* swap cred ptrs so free_mirror will clean up old */
if (lgr->range.iomode == IOMODE_READ) {
- cred = xchg(&mirror->ro_cred, cred);
- rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
+ old = xchg(&mirror->ro_cred, cred);
+ rcu_assign_pointer(fls->mirror_array[i]->ro_cred, old);
+ /* drop file if creds changed */
+ if (old != cred) {
+ filp = rcu_dereference_protected(xchg(&mirror->ro_file, NULL), 1);
+ if (filp)
+ fput(filp);
+ }
} else {
- cred = xchg(&mirror->rw_cred, cred);
- rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
+ old = xchg(&mirror->rw_cred, cred);
+ rcu_assign_pointer(fls->mirror_array[i]->rw_cred, old);
+ if (old != cred) {
+ filp = rcu_dereference_protected(xchg(&mirror->rw_file, NULL), 1);
+ if (filp)
+ fput(filp);
+ }
}
ff_layout_free_mirror(fls->mirror_array[i]);
fls->mirror_array[i] = mirror;
@@ -1757,6 +1825,7 @@ ff_layout_read_pagelist(struct nfs_pageio_descriptor *desc,
struct pnfs_layout_segment *lseg = hdr->lseg;
struct nfs4_pnfs_ds *ds;
struct rpc_clnt *ds_clnt;
+ struct file *filp;
struct nfs4_ff_layout_mirror *mirror;
const struct cred *ds_cred;
loff_t offset = hdr->args.offset;
@@ -1803,12 +1872,20 @@ ff_layout_read_pagelist(struct nfs_pageio_descriptor *desc,
hdr->args.offset = offset;
hdr->mds_offset = offset;

+ /* Start IO accounting for local read */
+ filp = ff_local_open_fh(lseg, idx, ds->ds_clp, ds_cred, fh,
+ FMODE_READ);
+ if (filp) {
+ hdr->task.tk_start = ktime_get();
+ ff_layout_read_record_layoutstats_start(&hdr->task, hdr);
+ }
+
/* Perform an asynchronous read to ds */
nfs_initiate_pgio(desc, ds->ds_clp, ds_clnt, hdr, ds_cred,
ds->ds_clp->rpc_ops,
vers == 3 ? &ff_layout_read_call_ops_v3 :
&ff_layout_read_call_ops_v4,
- 0, RPC_TASK_SOFTCONN, NULL);
+ 0, RPC_TASK_SOFTCONN, filp);
put_cred(ds_cred);
return PNFS_ATTEMPTED;

@@ -1829,6 +1906,7 @@ ff_layout_write_pagelist(struct nfs_pageio_descriptor *desc,
struct pnfs_layout_segment *lseg = hdr->lseg;
struct nfs4_pnfs_ds *ds;
struct rpc_clnt *ds_clnt;
+ struct file *filp;
struct nfs4_ff_layout_mirror *mirror;
const struct cred *ds_cred;
loff_t offset = hdr->args.offset;
@@ -1873,12 +1951,20 @@ ff_layout_write_pagelist(struct nfs_pageio_descriptor *desc,
*/
hdr->args.offset = offset;

+ /* Start IO accounting for local write */
+ filp = ff_local_open_fh(lseg, idx, ds->ds_clp, ds_cred, fh,
+ FMODE_READ|FMODE_WRITE);
+ if (filp) {
+ hdr->task.tk_start = ktime_get();
+ ff_layout_write_record_layoutstats_start(&hdr->task, hdr);
+ }
+
/* Perform an asynchronous write */
nfs_initiate_pgio(desc, ds->ds_clp, ds_clnt, hdr, ds_cred,
ds->ds_clp->rpc_ops,
vers == 3 ? &ff_layout_write_call_ops_v3 :
&ff_layout_write_call_ops_v4,
- sync, RPC_TASK_SOFTCONN, NULL);
+ sync, RPC_TASK_SOFTCONN, filp);
put_cred(ds_cred);
return PNFS_ATTEMPTED;

@@ -1912,6 +1998,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
struct pnfs_layout_segment *lseg = data->lseg;
struct nfs4_pnfs_ds *ds;
struct rpc_clnt *ds_clnt;
+ struct file *filp;
struct nfs4_ff_layout_mirror *mirror;
const struct cred *ds_cred;
u32 idx;
@@ -1950,10 +2037,18 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
if (fh)
data->args.fh = fh;

+ /* Start IO accounting for local commit */
+ filp = ff_local_open_fh(lseg, idx, ds->ds_clp, ds_cred, fh,
+ FMODE_READ|FMODE_WRITE);
+ if (filp) {
+ data->task.tk_start = ktime_get();
+ ff_layout_commit_record_layoutstats_start(&data->task, data);
+ }
+
ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
- vers == 3 ? &ff_layout_commit_call_ops_v3 :
- &ff_layout_commit_call_ops_v4,
- how, RPC_TASK_SOFTCONN, NULL);
+ vers == 3 ? &ff_layout_commit_call_ops_v3 :
+ &ff_layout_commit_call_ops_v4,
+ how, RPC_TASK_SOFTCONN, filp);
put_cred(ds_cred);
return ret;
out_err:
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h
index f84b3fb0dddd..8e042df5a2c9 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -82,7 +82,9 @@ struct nfs4_ff_layout_mirror {
struct nfs_fh *fh_versions;
nfs4_stateid stateid;
const struct cred __rcu *ro_cred;
+ struct file __rcu *ro_file;
const struct cred __rcu *rw_cred;
+ struct file __rcu *rw_file;
refcount_t ref;
spinlock_t lock;
unsigned long flags;
diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
index e028f5a0ef5f..e58bedfb1dcc 100644
--- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c
+++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
@@ -395,6 +395,12 @@ nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg,

/* connect success, check rsize/wsize limit */
if (!status) {
+ /*
+ * ds_clp is put in destroy_ds().
+ * keep ds_clp even if DS is local, so that if local IO cannot
+ * proceed somehow, we can fall back to NFS whenever we want.
+ */
+ nfs_local_probe(ds->ds_clp);
max_payload =
nfs_block_size(rpc_max_payload(ds->ds_clp->cl_rpcclient),
NULL);
--
2.44.0