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authorPaulo Alcantara (SUSE) <paulo@paulo.ac>2019-07-17 01:04:50 +0300
committerSteve French <stfrench@microsoft.com>2019-09-16 19:43:38 +0300
commit8eecd1c2e5bc73d33f3a544751305679dbf88eb4 (patch)
tree3f908c5e60132624f86d3565d468a18ddd066d42 /fs
parent0892ba693f304ce3e9ca1f0a64a5cfc051454996 (diff)
downloadlinux-8eecd1c2e5bc73d33f3a544751305679dbf88eb4.tar.xz
cifs: Add support for root file systems
Introduce a new CONFIG_CIFS_ROOT option to handle root file systems over a SMB share. In order to mount the root file system during the init process, make cifs.ko perform non-blocking socket operations while mounting and accessing it. Cc: Steve French <smfrench@gmail.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Paulo Alcantara (SUSE) <paulo@paulo.ac> Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/Kconfig8
-rw-r--r--fs/cifs/Makefile2
-rw-r--r--fs/cifs/cifsglob.h2
-rw-r--r--fs/cifs/cifsroot.c83
-rw-r--r--fs/cifs/connect.c17
5 files changed, 109 insertions, 3 deletions
diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index b16219e5dac9..99a22e57660e 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -211,3 +211,11 @@ config CIFS_FSCACHE
Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
to be cached locally on disk through the general filesystem cache
manager. If unsure, say N.
+
+config CIFS_ROOT
+ bool "SMB root file system (Experimental)"
+ depends on CIFS=y && IP_PNP
+ help
+ Enables root file system support over SMB protocol.
+
+ Most people say N here.
diff --git a/fs/cifs/Makefile b/fs/cifs/Makefile
index 41332f20055b..51bae9340842 100644
--- a/fs/cifs/Makefile
+++ b/fs/cifs/Makefile
@@ -21,3 +21,5 @@ cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o cifs_dfs_ref.o dfs_cache.o
cifs-$(CONFIG_CIFS_FSCACHE) += fscache.o cache.o
cifs-$(CONFIG_CIFS_SMB_DIRECT) += smbdirect.o
+
+cifs-$(CONFIG_CIFS_ROOT) += cifsroot.o
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 09b60ec5de3e..54e204589cb9 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -607,6 +607,7 @@ struct smb_vol {
__u32 handle_timeout; /* persistent and durable handle timeout in ms */
unsigned int max_credits; /* smb3 max_credits 10 < credits < 60000 */
__u16 compression; /* compression algorithm 0xFFFF default 0=disabled */
+ bool rootfs:1; /* if it's a SMB root file system */
};
/**
@@ -764,6 +765,7 @@ struct TCP_Server_Info {
* reconnect.
*/
int nr_targets;
+ bool noblockcnt; /* use non-blocking connect() */
};
struct cifs_credits {
diff --git a/fs/cifs/cifsroot.c b/fs/cifs/cifsroot.c
new file mode 100644
index 000000000000..8760d9cbf25e
--- /dev/null
+++ b/fs/cifs/cifsroot.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SMB root file system support
+ *
+ * Copyright (c) 2019 Paulo Alcantara <palcantara@suse.de>
+ */
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/root_dev.h>
+#include <linux/kernel.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <net/ipconfig.h>
+
+#define DEFAULT_MNT_OPTS \
+ "vers=1.0,cifsacl,mfsymlinks,rsize=1048576,wsize=65536,uid=0,gid=0," \
+ "hard,rootfs"
+
+static char root_dev[2048] __initdata = "";
+static char root_opts[1024] __initdata = DEFAULT_MNT_OPTS;
+
+static __be32 __init parse_srvaddr(char *start, char *end)
+{
+ char addr[sizeof("aaa.bbb.ccc.ddd")];
+ int i = 0;
+
+ while (start < end && i < sizeof(addr) - 1) {
+ if (isdigit(*start) || *start == '.')
+ addr[i++] = *start;
+ start++;
+ }
+ addr[i] = '\0';
+ return in_aton(addr);
+}
+
+/* cifsroot=//<server-ip>/<share>[,options] */
+static int __init cifs_root_setup(char *line)
+{
+ char *s;
+ int len;
+ __be32 srvaddr = htonl(INADDR_NONE);
+
+ ROOT_DEV = Root_CIFS;
+
+ if (strlen(line) > 3 && line[0] == '/' && line[1] == '/') {
+ s = strchr(&line[2], '/');
+ if (!s || s[1] == '\0')
+ return 1;
+
+ s = strchrnul(s, ',');
+ len = s - line + 1;
+ if (len <= sizeof(root_dev)) {
+ strlcpy(root_dev, line, len);
+ srvaddr = parse_srvaddr(&line[2], s);
+ if (*s) {
+ snprintf(root_opts, sizeof(root_opts), "%s,%s",
+ DEFAULT_MNT_OPTS, s + 1);
+ }
+ }
+ }
+
+ root_server_addr = srvaddr;
+
+ return 1;
+}
+
+__setup("cifsroot=", cifs_root_setup);
+
+int __init cifs_root_data(char **dev, char **opts)
+{
+ if (!root_dev[0] || root_server_addr == htonl(INADDR_NONE)) {
+ printk(KERN_ERR "Root-CIFS: no SMB server address\n");
+ return -1;
+ }
+
+ *dev = root_dev;
+ *opts = root_opts;
+
+ return 0;
+}
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index e16b6cc1e31b..2850c3ce4391 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -96,7 +96,7 @@ enum {
Opt_multiuser, Opt_sloppy, Opt_nosharesock,
Opt_persistent, Opt_nopersistent,
Opt_resilient, Opt_noresilient,
- Opt_domainauto, Opt_rdma, Opt_modesid,
+ Opt_domainauto, Opt_rdma, Opt_modesid, Opt_rootfs,
Opt_compress,
/* Mount options which take numeric value */
@@ -266,6 +266,7 @@ static const match_table_t cifs_mount_option_tokens = {
{ Opt_ignore, "nomand" },
{ Opt_ignore, "relatime" },
{ Opt_ignore, "_netdev" },
+ { Opt_rootfs, "rootfs" },
{ Opt_err, NULL }
};
@@ -1777,6 +1778,11 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
case Opt_nodfs:
vol->nodfs = 1;
break;
+ case Opt_rootfs:
+#ifdef CONFIG_CIFS_ROOT
+ vol->rootfs = true;
+#endif
+ break;
case Opt_posixpaths:
vol->posix_paths = 1;
break;
@@ -2727,7 +2733,8 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
goto out_err_crypto_release;
}
- tcp_ses->noblocksnd = volume_info->noblocksnd;
+ tcp_ses->noblockcnt = volume_info->rootfs;
+ tcp_ses->noblocksnd = volume_info->noblocksnd || volume_info->rootfs;
tcp_ses->noautotune = volume_info->noautotune;
tcp_ses->tcp_nodelay = volume_info->sockopt_tcp_nodelay;
tcp_ses->rdma = volume_info->rdma;
@@ -3873,7 +3880,11 @@ generic_ip_connect(struct TCP_Server_Info *server)
socket->sk->sk_sndbuf,
socket->sk->sk_rcvbuf, socket->sk->sk_rcvtimeo);
- rc = socket->ops->connect(socket, saddr, slen, 0);
+ rc = socket->ops->connect(socket, saddr, slen,
+ server->noblockcnt ? O_NONBLOCK : 0);
+
+ if (rc == -EINPROGRESS)
+ rc = 0;
if (rc < 0) {
cifs_dbg(FYI, "Error %d connecting to server\n", rc);
sock_release(socket);