From: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
There are some workloads where READ_PLUS might end up hurting
performance, so let's be nice to users and provide a way to disable this
operation similar to how READDIR_PLUS can be disabled.
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
---
fs/nfs/fs_context.c | 14 ++++++++++++++
fs/nfs/nfs4client.c | 3 +++
include/linux/nfs_fs_sb.h | 1 +
3 files changed, 18 insertions(+)
diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index 0247dcb7b316..82ba07c7c1ce 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -64,6 +64,7 @@ enum nfs_param {
Opt_proto,
Opt_rdirplus,
Opt_rdma,
+ Opt_readplus,
Opt_resvport,
Opt_retrans,
Opt_retry,
@@ -120,6 +121,7 @@ static const struct fs_parameter_spec nfs_param_specs[] = {
fsparam_string("proto", Opt_proto),
fsparam_flag_no("rdirplus", Opt_rdirplus),
fsparam_flag ("rdma", Opt_rdma),
+ fsparam_flag_no("readplus", Opt_readplus),
fsparam_flag_no("resvport", Opt_resvport),
fsparam_u32 ("retrans", Opt_retrans),
fsparam_string("retry", Opt_retry),
@@ -555,6 +557,12 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
else
ctx->options |= NFS_OPTION_MIGRATION;
break;
+ case Opt_readplus:
+ if (result.negated)
+ ctx->options |= NFS_OPTION_NO_READ_PLUS;
+ else
+ ctx->options &= ~NFS_OPTION_NO_READ_PLUS;
+ break;
/*
* options that take numeric values
@@ -1176,6 +1184,10 @@ static int nfs_fs_context_validate(struct fs_context *fc)
(ctx->version != 4 || ctx->minorversion != 0))
goto out_migration_misuse;
+ if (ctx->options & NFS_OPTION_NO_READ_PLUS &&
+ (ctx->version != 4 || ctx->minorversion < 2))
+ goto out_noreadplus_misuse;
+
/* Verify that any proto=/mountproto= options match the address
* families in the addr=/mountaddr= options.
*/
@@ -1254,6 +1266,8 @@ static int nfs_fs_context_validate(struct fs_context *fc)
ctx->version, ctx->minorversion);
out_migration_misuse:
return nfs_invalf(fc, "NFS: 'Migration' not supported for this NFS version");
+out_noreadplus_misuse:
+ return nfs_invalf(fc, "NFS: 'noreadplus' not supported for this NFS version\n");
out_version_unavailable:
nfs_errorf(fc, "NFS: Version unavailable");
return ret;
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 0cd767e5c977..868dc3c36ba1 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -1016,6 +1016,9 @@ static int nfs4_server_common_setup(struct nfs_server *server,
server->caps |= server->nfs_client->cl_mvops->init_caps;
if (server->flags & NFS_MOUNT_NORDIRPLUS)
server->caps &= ~NFS_CAP_READDIRPLUS;
+ if (server->options & NFS_OPTION_NO_READ_PLUS)
+ server->caps &= ~NFS_CAP_READ_PLUS;
+
/*
* Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
* authentication.
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 11248c5a7b24..360e70c7bbb6 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -172,6 +172,7 @@ struct nfs_server {
unsigned int clone_blksize; /* granularity of a CLONE operation */
#define NFS_OPTION_FSCACHE 0x00000001 /* - local caching enabled */
#define NFS_OPTION_MIGRATION 0x00000002 /* - NFSv4 migration enabled */
+#define NFS_OPTION_NO_READ_PLUS 0x00000004 /* - NFSv4.2 READ_PLUS enabled */
struct nfs_fsid fsid;
__u64 maxfilesize; /* maximum file size */
--
2.24.1
