Expose a per-mount knob in sysfs to set the READDIR requested attributes
for a non-plus READDIR request.
For example:
echo 0x800 0x800000 0x0 > /sys/fs/nfs/0\:57/v4_readdir_attrs
.. will revert the client to only request rdattr_error and
mounted_on_fileid for any non "plus" READDIR, as before the patch
preceeding this one in this series. This provides existing installations
an option to fix a potential performance regression that may occur after
NFS clients update to request additional default READDIR attributes.
Hide the functionality behind CONFIG_NFS_EXPERT_SYSFS.
Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
---
fs/nfs/Kconfig | 7 +++
fs/nfs/client.c | 4 ++
fs/nfs/nfs4client.c | 4 ++
fs/nfs/nfs4proc.c | 1 +
fs/nfs/nfs4xdr.c | 7 ++-
fs/nfs/sysfs.c | 91 +++++++++++++++++++++++++++++++++++++++
include/linux/nfs_fs_sb.h | 1 +
include/linux/nfs_xdr.h | 1 +
8 files changed, 112 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index 7df2503cef6c..667b1531889c 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -212,3 +212,10 @@ config NFS_V4_2_READ_PLUS
default y
help
Choose Y here to enable use of the NFS v4.2 READ_PLUS operation.
+
+config NFS_EXPERT_SYSFS
+ bool "NFS: Enable the support for expert tuning of nfs behaviors"
+ default n
+ help
+ This option allows potentially dangerous modifications to the default
+ behaviors of the NFS client via files within sysfs.
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 44eca51b2808..981a2437b752 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -922,6 +922,10 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
target->options = source->options;
target->auth_info = source->auth_info;
target->port = source->port;
+#if IS_ENABLED(CONFIG_NFS_V4)
+ memcpy(target->readdir_attrs, source->readdir_attrs,
+ sizeof(target->readdir_attrs));
+#endif
}
EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 11e3a285594c..3bbfb4244c14 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -1115,6 +1115,10 @@ static int nfs4_server_common_setup(struct nfs_server *server,
nfs4_server_set_init_caps(server);
+ /* Default (non-plus) v4 readdir attributes */
+ server->readdir_attrs[0] = FATTR4_WORD0_TYPE|FATTR4_WORD0_RDATTR_ERROR;
+ server->readdir_attrs[1] = FATTR4_WORD1_MOUNTED_ON_FILEID;
+
/* Probe the root fh to retrieve its FSID and filehandle */
error = nfs4_get_rootfh(server, mntfh, auth_probe);
if (error < 0)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 7016eaadf555..0f0028de7941 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5113,6 +5113,7 @@ static int _nfs4_proc_readdir(struct nfs_readdir_arg *nr_arg,
.pgbase = 0,
.count = nr_arg->page_len,
.plus = nr_arg->plus,
+ .server = server,
};
struct nfs4_readdir_res res;
struct rpc_message msg = {
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 7200d6f7cd7b..45a9b40b801e 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1601,16 +1601,15 @@ static void encode_read(struct xdr_stream *xdr, const struct nfs_pgio_args *args
static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg *readdir, struct rpc_rqst *req, struct compound_hdr *hdr)
{
- uint32_t attrs[3] = {
- FATTR4_WORD0_TYPE|FATTR4_WORD0_RDATTR_ERROR,
- FATTR4_WORD1_MOUNTED_ON_FILEID,
- };
+ uint32_t attrs[3];
uint32_t dircount = readdir->count;
uint32_t maxcount = readdir->count;
__be32 *p, verf[2];
uint32_t attrlen = 0;
unsigned int i;
+ memcpy(attrs, readdir->server->readdir_attrs, sizeof(attrs));
+
if (readdir->plus) {
attrs[0] |= FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE|
FATTR4_WORD0_FSID|FATTR4_WORD0_FILEHANDLE|FATTR4_WORD0_FILEID;
diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c
index bf378ecd5d9f..80936e8b5b80 100644
--- a/fs/nfs/sysfs.c
+++ b/fs/nfs/sysfs.c
@@ -272,6 +272,87 @@ shutdown_store(struct kobject *kobj, struct kobj_attribute *attr,
static struct kobj_attribute nfs_sysfs_attr_shutdown = __ATTR_RW(shutdown);
+#if IS_ENABLED(CONFIG_NFS_V4)
+#ifdef CONFIG_NFS_EXPERT_SYSFS
+static ssize_t
+v4_readdir_attrs_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ struct nfs_server *server;
+
+ server = container_of(kobj, struct nfs_server, kobj);
+
+ return sysfs_emit(buf, "0x%x 0x%x 0x%x\n",
+ server->readdir_attrs[0],
+ server->readdir_attrs[1],
+ server->readdir_attrs[2]);
+}
+
+static ssize_t
+v4_readdir_attrs_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct nfs_server *server;
+ u32 attrs[3];
+ char p[36], *v;
+ size_t token = 0;
+ int i;
+
+ if (count > 36)
+ return -EINVAL;
+
+ v = strncpy(p, buf, count);
+
+ for (i = 0; i < 3; i++) {
+ token += strcspn(v, " ") + 1;
+ if (token > 34)
+ return -EINVAL;
+
+ p[token - 1] = '\0';
+ if (kstrtoint(v, 0, &attrs[i]))
+ return -EINVAL;
+ v = &p[token];
+ }
+
+ /* Allow only what we decode - see decode_getfattr_attrs() */
+ if (attrs[0] & ~(FATTR4_WORD0_TYPE |
+ FATTR4_WORD0_CHANGE |
+ FATTR4_WORD0_SIZE |
+ FATTR4_WORD0_FSID |
+ FATTR4_WORD0_RDATTR_ERROR |
+ FATTR4_WORD0_FILEHANDLE |
+ FATTR4_WORD0_FILEID |
+ FATTR4_WORD0_FS_LOCATIONS) ||
+ attrs[1] & ~(FATTR4_WORD1_MODE |
+ FATTR4_WORD1_NUMLINKS |
+ FATTR4_WORD1_OWNER |
+ FATTR4_WORD1_OWNER_GROUP |
+ FATTR4_WORD1_RAWDEV |
+ FATTR4_WORD1_SPACE_USED |
+ FATTR4_WORD1_TIME_ACCESS |
+ FATTR4_WORD1_TIME_METADATA |
+ FATTR4_WORD1_TIME_MODIFY |
+ FATTR4_WORD1_MOUNTED_ON_FILEID) ||
+ attrs[2] & ~(FATTR4_WORD2_MDSTHRESHOLD |
+ FATTR4_WORD2_SECURITY_LABEL))
+ return -EINVAL;
+
+ server = container_of(kobj, struct nfs_server, kobj);
+
+ if (attrs[0])
+ server->readdir_attrs[0] = attrs[0];
+ if (attrs[1])
+ server->readdir_attrs[1] = attrs[1];
+ if (attrs[2])
+ server->readdir_attrs[2] = attrs[2];
+
+ return count;
+}
+
+static struct kobj_attribute nfs_sysfs_attr_v4_readdir_attrs = __ATTR_RW(v4_readdir_attrs);
+#endif /* CONFIG_NFS_EXPERT_SYSFS */
+#endif /* CONFIG_NFS_V4 */
+
#define RPC_CLIENT_NAME_SIZE 64
void nfs_sysfs_link_rpc_client(struct nfs_server *server,
@@ -325,6 +406,16 @@ void nfs_sysfs_add_server(struct nfs_server *server)
if (ret < 0)
pr_warn("NFS: sysfs_create_file_ns for server-%d failed (%d)\n",
server->s_sysfs_id, ret);
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+#ifdef CONFIG_NFS_EXPERT_SYSFS
+ ret = sysfs_create_file_ns(&server->kobj, &nfs_sysfs_attr_v4_readdir_attrs.attr,
+ nfs_netns_server_namespace(&server->kobj));
+ if (ret < 0)
+ pr_warn("NFS: sysfs_create_file_ns for server-%d failed (%d)\n",
+ server->s_sysfs_id, ret);
+#endif /* CONFIG_NFS_EXPERT_SYSFS */
+#endif /* IS_ENABLED(CONFIG_NFS_V4) */
}
EXPORT_SYMBOL_GPL(nfs_sysfs_add_server);
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index cd628c4b011e..db87261b7cd7 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -219,6 +219,7 @@ struct nfs_server {
of change attribute, size, ctime
and mtime attributes supported by
the server */
+ u32 readdir_attrs[3]; /* V4 tuneable default readdir attrs */
u32 acl_bitmask; /* V4 bitmask representing the ACEs
that are supported on this
filesystem */
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 12bbb5c63664..e05d861b1788 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1142,6 +1142,7 @@ struct nfs4_readdir_arg {
struct page ** pages; /* zero-copy data */
unsigned int pgbase; /* zero-copy data */
const u32 * bitmask;
+ const struct nfs_server *server;
bool plus;
};
--
2.41.0
