nfs: cache all open LOCALIO nfsd_file(s) in client

This commit switches from leaning heavily on NFSD's filecache (in
terms of GC'd nfsd_files) back to caching nfsd_files in the
client. A later commit will add the callback mechanism needed to
allow NFSD to force the NFS client to cleanup all cached nfsd_files.

Add nfs_fh_localio_init() and 'struct nfs_fh_localio' to cache opened
nfsd_file(s) (both a RO and RW nfsd_file is able to be opened and
cached for a given nfs_fh).

Update nfs_local_open_fh() to cache the nfsd_file once it is opened
using __nfs_local_open_fh().

Introduce nfs_close_local_fh() to clear the cached open nfsd_files and
call nfs_to_nfsd_file_put_local().

Refcounting is such that:
- nfs_local_open_fh() is paired with nfs_close_local_fh().
- __nfs_local_open_fh() is paired with nfs_to_nfsd_file_put_local().
- nfs_local_file_get() is paired with nfs_local_file_put().

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index e27c07bd8929..11968dcb7243 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -961,8 +961,9 @@ static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
 		struct nfs_client *clp = NFS_SERVER(hdr->inode)->nfs_client;
 
 		struct nfsd_file *localio =
-			nfs_local_open_fh(clp, hdr->cred,
-					  hdr->args.fh, hdr->args.context->mode);
+			nfs_local_open_fh(clp, hdr->cred, hdr->args.fh,
+					  &hdr->args.context->nfl,
+					  hdr->args.context->mode);
 
 		if (NFS_SERVER(hdr->inode)->nfs_client->cl_minorversion)
 			task_flags = RPC_TASK_MOVEABLE;