9p: Implement show_options

Implement the show_options superblock op for 9p as part of a bid to get
rid of s_options and generic_show_options() to make it easier to implement
a context-based mount where the mount options can be passed individually
over a file descriptor.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Ron Minnich <rminnich@sandia.gov>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: v9fs-developer@lists.sourceforge.net
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

8 files changed, 161 insertions, 10 deletions

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index c202930086ed..8fb89ddc6cc7 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -33,6 +33,7 @@
 #include <linux/parser.h>
 #include <linux/idr.h>
 #include <linux/slab.h>
+#include <linux/seq_file.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 #include <net/9p/transport.h>
@@ -82,6 +83,13 @@ static const match_table_t tokens = {
         {Opt_err, NULL}
 };
 
+static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
+        [CACHE_NONE]    = "none",
+        [CACHE_MMAP]    = "mmap",
+        [CACHE_LOOSE]   = "loose",
+        [CACHE_FSCACHE] = "fscache",
+};
+
 /* Interpret mount options for cache mode */
 static int get_cache_mode(char *s)
 {
@@ -104,6 +112,58 @@ static int get_cache_mode(char *s)
         return version;
 }
 
+/*
+ * Display the mount options in /proc/mounts.
+ */
+int v9fs_show_options(struct seq_file *m, struct dentry *root)
+{
+        struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
+
+        if (v9ses->debug)
+                seq_printf(m, ",debug=%x", v9ses->debug);
+        if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
+                seq_printf(m, ",dfltuid=%u",
+                           from_kuid_munged(&init_user_ns, v9ses->dfltuid));
+        if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
+                seq_printf(m, ",dfltgid=%u",
+                           from_kgid_munged(&init_user_ns, v9ses->dfltgid));
+        if (v9ses->afid != ~0)
+                seq_printf(m, ",afid=%u", v9ses->afid);
+        if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
+                seq_printf(m, ",uname=%s", v9ses->uname);
+        if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
+                seq_printf(m, ",aname=%s", v9ses->aname);
+        if (v9ses->nodev)
+                seq_puts(m, ",nodevmap");
+        if (v9ses->cache)
+                seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
+#ifdef CONFIG_9P_FSCACHE
+        if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
+                seq_printf(m, ",cachetag=%s", v9ses->cachetag);
+#endif
+
+        switch (v9ses->flags & V9FS_ACCESS_MASK) {
+        case V9FS_ACCESS_USER:
+                seq_puts(m, ",access=user");
+                break;
+        case V9FS_ACCESS_ANY:
+                seq_puts(m, ",access=any");
+                break;
+        case V9FS_ACCESS_CLIENT:
+                seq_puts(m, ",access=client");
+                break;
+        case V9FS_ACCESS_SINGLE:
+                seq_printf(m, ",access=%u",
+                           from_kuid_munged(&init_user_ns, v9ses->uid));
+                break;
+        }
+
+        if (v9ses->flags & V9FS_POSIX_ACL)
+                seq_puts(m, ",posixacl");
+
+        return p9_show_client_options(m, v9ses->clnt);
+}
+
 /**
  * v9fs_parse_options - parse mount options into session structure
  * @v9ses: existing v9fs session information
@@ -230,6 +290,7 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
                         break;
                 case Opt_cachetag:
 #ifdef CONFIG_9P_FSCACHE
+                        kfree(v9ses->cachetag);
                         v9ses->cachetag = match_strdup(&args[0]);
 #endif
                         break;
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 76eaf49abd3a..982e017acadb 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -67,6 +67,7 @@ enum p9_cache_modes {
         CACHE_MMAP,
         CACHE_LOOSE,
         CACHE_FSCACHE,
+        nr__p9_cache_modes
 };
 
 /**
@@ -137,6 +138,8 @@ static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
         return container_of(inode, struct v9fs_inode, vfs_inode);
 }
 
+extern int v9fs_show_options(struct seq_file *m, struct dentry *root);
+
 struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
                                                                         char *);
 extern void v9fs_session_close(struct v9fs_session_info *v9ses);
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index a0965fb587a5..8b75463cb211 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -33,7 +33,6 @@
 #include <linux/string.h>
 #include <linux/inet.h>
 #include <linux/pagemap.h>
-#include <linux/seq_file.h>
 #include <linux/mount.h>
 #include <linux/idr.h>
 #include <linux/sched.h>
@@ -104,7 +103,6 @@ v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
                 sb->s_flags |= MS_POSIXACL;
 #endif
 
-        save_mount_options(sb, data);
         return 0;
 }
 
@@ -349,7 +347,7 @@ static const struct super_operations v9fs_super_ops = {
         .destroy_inode = v9fs_destroy_inode,
         .statfs = simple_statfs,
         .evict_inode = v9fs_evict_inode,
-        .show_options = generic_show_options,
+        .show_options = v9fs_show_options,
         .umount_begin = v9fs_umount_begin,
         .write_inode = v9fs_write_inode,
 };
@@ -360,7 +358,7 @@ static const struct super_operations v9fs_super_ops_dotl = {
         .statfs = v9fs_statfs,
         .drop_inode = v9fs_drop_inode,
         .evict_inode = v9fs_evict_inode,
-        .show_options = generic_show_options,
+        .show_options = v9fs_show_options,
         .umount_begin = v9fs_umount_begin,
         .write_inode = v9fs_write_inode_dotl,
 };
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index b582339ccef5..7af9d769b97d 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -157,6 +157,18 @@ struct p9_client {
         enum p9_trans_status status;
         void *trans;
 
+        union {
+                struct {
+                        int rfd;
+                        int wfd;
+                } fd;
+                struct {
+                        u16 port;
+                        bool privport;
+
+                } tcp;
+        } trans_opts;
+
         struct p9_idpool *fidpool;
         struct list_head fidlist;
 
@@ -213,6 +225,7 @@ struct p9_dirent {
 
 struct iov_iter;
 
+int p9_show_client_options(struct seq_file *m, struct p9_client *clnt);
 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
 int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
                      const char *name);
diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index 5122b5e40f78..1625fb842ac4 100644
--- a/include/net/9p/transport.h
+++ b/include/net/9p/transport.h
@@ -62,6 +62,7 @@ struct p9_trans_module {
         int (*cancelled)(struct p9_client *, struct p9_req_t *req);
         int (*zc_request)(struct p9_client *, struct p9_req_t *,
                           struct iov_iter *, struct iov_iter *, int , int, int);
+        int (*show_options)(struct seq_file *, struct p9_client *);
 };
 
 void v9fs_register_trans(struct p9_trans_module *m);
diff --git a/net/9p/client.c b/net/9p/client.c
index 1218fb3b52da..4674235b0d9b 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -37,6 +37,7 @@
 #include <linux/uio.h>
 #include <net/9p/9p.h>
 #include <linux/parser.h>
+#include <linux/seq_file.h>
 #include <net/9p/client.h>
 #include <net/9p/transport.h>
 #include "protocol.h"
@@ -77,6 +78,30 @@ inline int p9_is_proto_dotu(struct p9_client *clnt)
 }
 EXPORT_SYMBOL(p9_is_proto_dotu);
 
+int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
+{
+        if (clnt->msize != 8192)
+                seq_printf(m, ",msize=%u", clnt->msize);
+        seq_printf(m, "trans=%s", clnt->trans_mod->name);
+
+        switch (clnt->proto_version) {
+        case p9_proto_legacy:
+                seq_puts(m, ",noextend");
+                break;
+        case p9_proto_2000u:
+                seq_puts(m, ",version=9p2000.u");
+                break;
+        case p9_proto_2000L:
+                /* Default */
+                break;
+        }
+
+        if (clnt->trans_mod->show_options)
+                return clnt->trans_mod->show_options(m, clnt);
+        return 0;
+}
+EXPORT_SYMBOL(p9_show_client_options);
+
 /*
  * Some error codes are taken directly from the server replies,
  * make sure they are valid.
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 7bc2208b6cc4..f2e0eaf58018 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -41,6 +41,7 @@
 #include <linux/file.h>
 #include <linux/parser.h>
 #include <linux/slab.h>
+#include <linux/seq_file.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 #include <net/9p/transport.h>
@@ -51,6 +52,9 @@
 #define MAX_SOCK_BUF (64*1024)
 #define MAXPOLLWADDR    2
 
+static struct p9_trans_module p9_tcp_trans;
+static struct p9_trans_module p9_fd_trans;
+
 /**
  * struct p9_fd_opts - per-transport options
  * @rfd: file descriptor for reading (trans=fd)
@@ -63,7 +67,7 @@ struct p9_fd_opts {
         int rfd;
         int wfd;
         u16 port;
-        int privport;
+        bool privport;
 };
 
 /*
@@ -720,6 +724,20 @@ static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req)
         return 0;
 }
 
+static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt)
+{
+        if (clnt->trans_mod == &p9_tcp_trans) {
+                if (clnt->trans_opts.tcp.port != P9_PORT)
+                        seq_printf(m, "port=%u", clnt->trans_opts.tcp.port);
+        } else if (clnt->trans_mod == &p9_fd_trans) {
+                if (clnt->trans_opts.fd.rfd != ~0)
+                        seq_printf(m, "rfd=%u", clnt->trans_opts.fd.rfd);
+                if (clnt->trans_opts.fd.wfd != ~0)
+                        seq_printf(m, "wfd=%u", clnt->trans_opts.fd.wfd);
+        }
+        return 0;
+}
+
 /**
  * parse_opts - parse mount options into p9_fd_opts structure
  * @params: options string passed from mount
@@ -738,7 +756,7 @@ static int parse_opts(char *params, struct p9_fd_opts *opts)
         opts->port = P9_PORT;
         opts->rfd = ~0;
         opts->wfd = ~0;
-        opts->privport = 0;
+        opts->privport = false;
 
         if (!params)
                 return 0;
@@ -776,7 +794,7 @@ static int parse_opts(char *params, struct p9_fd_opts *opts)
                         opts->wfd = option;
                         break;
                 case Opt_privport:
-                        opts->privport = 1;
+                        opts->privport = true;
                         break;
                 default:
                         continue;
@@ -942,6 +960,8 @@ p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
 
         csocket = NULL;
 
+        client->trans_opts.tcp.port = opts.port;
+        client->trans_opts.tcp.privport = opts.privport;
         sin_server.sin_family = AF_INET;
         sin_server.sin_addr.s_addr = in_aton(addr);
         sin_server.sin_port = htons(opts.port);
@@ -1020,6 +1040,8 @@ p9_fd_create(struct p9_client *client, const char *addr, char *args)
         struct p9_fd_opts opts;
 
         parse_opts(args, &opts);
+        client->trans_opts.fd.rfd = opts.rfd;
+        client->trans_opts.fd.wfd = opts.wfd;
 
         if (opts.rfd == ~0 || opts.wfd == ~0) {
                 pr_err("Insufficient options for proto=fd\n");
@@ -1044,6 +1066,7 @@ static struct p9_trans_module p9_tcp_trans = {
         .request = p9_fd_request,
         .cancel = p9_fd_cancel,
         .cancelled = p9_fd_cancelled,
+        .show_options = p9_fd_show_options,
         .owner = THIS_MODULE,
 };
 
@@ -1056,6 +1079,7 @@ static struct p9_trans_module p9_unix_trans = {
         .request = p9_fd_request,
         .cancel = p9_fd_cancel,
         .cancelled = p9_fd_cancelled,
+        .show_options = p9_fd_show_options,
         .owner = THIS_MODULE,
 };
 
@@ -1068,6 +1092,7 @@ static struct p9_trans_module p9_fd_trans = {
         .request = p9_fd_request,
         .cancel = p9_fd_cancel,
         .cancelled = p9_fd_cancelled,
+        .show_options = p9_fd_show_options,
         .owner = THIS_MODULE,
 };
 
diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index 553ed4ecb6a0..6d8e3031978f 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -43,6 +43,7 @@
 #include <linux/parser.h>
 #include <linux/semaphore.h>
 #include <linux/slab.h>
+#include <linux/seq_file.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 #include <net/9p/transport.h>
@@ -70,6 +71,8 @@
  * @dm_mr: DMA Memory Region pointer
  * @lkey: The local access only memory region key
  * @timeout: Number of uSecs to wait for connection management events
+ * @privport: Whether a privileged port may be used
+ * @port: The port to use
  * @sq_depth: The depth of the Send Queue
  * @sq_sem: Semaphore for the SQ
  * @rq_depth: The depth of the Receive Queue.
@@ -95,6 +98,8 @@ struct p9_trans_rdma {
         struct ib_qp *qp;
         struct ib_cq *cq;
         long timeout;
+        bool privport;
+        u16 port;
         int sq_depth;
         struct semaphore sq_sem;
         int rq_depth;
@@ -133,10 +138,10 @@ struct p9_rdma_context {
  */
 struct p9_rdma_opts {
         short port;
+        bool privport;
         int sq_depth;
         int rq_depth;
         long timeout;
-        int privport;
 };
 
 /*
@@ -159,6 +164,23 @@ static match_table_t tokens = {
         {Opt_err, NULL},
 };
 
+static int p9_rdma_show_options(struct seq_file *m, struct p9_client *clnt)
+{
+        struct p9_trans_rdma *rdma = clnt->trans;
+
+        if (rdma->port != P9_PORT)
+                seq_printf(m, ",port=%u", rdma->port);
+        if (rdma->sq_depth != P9_RDMA_SQ_DEPTH)
+                seq_printf(m, ",sq=%u", rdma->sq_depth);
+        if (rdma->rq_depth != P9_RDMA_RQ_DEPTH)
+                seq_printf(m, ",rq=%u", rdma->rq_depth);
+        if (rdma->timeout != P9_RDMA_TIMEOUT)
+                seq_printf(m, ",timeout=%lu", rdma->timeout);
+        if (rdma->privport)
+                seq_puts(m, ",privport");
+        return 0;
+}
+
 /**
  * parse_opts - parse mount options into rdma options structure
  * @params: options string passed from mount
@@ -177,7 +199,7 @@ static int parse_opts(char *params, struct p9_rdma_opts *opts)
         opts->sq_depth = P9_RDMA_SQ_DEPTH;
         opts->rq_depth = P9_RDMA_RQ_DEPTH;
         opts->timeout = P9_RDMA_TIMEOUT;
-        opts->privport = 0;
+        opts->privport = false;
 
         if (!params)
                 return 0;
@@ -218,7 +240,7 @@ static int parse_opts(char *params, struct p9_rdma_opts *opts)
                         opts->timeout = option;
                         break;
                 case Opt_privport:
-                        opts->privport = 1;
+                        opts->privport = true;
                         break;
                 default:
                         continue;
@@ -560,6 +582,8 @@ static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
         if (!rdma)
                 return NULL;
 
+        rdma->port = opts->port;
+        rdma->privport = opts->privport;
         rdma->sq_depth = opts->sq_depth;
         rdma->rq_depth = opts->rq_depth;
         rdma->timeout = opts->timeout;
@@ -733,6 +757,7 @@ static struct p9_trans_module p9_rdma_trans = {
         .request = rdma_request,
         .cancel = rdma_cancel,
         .cancelled = rdma_cancelled,
+        .show_options = p9_rdma_show_options,
 };
 
 /**