xref: /openbmc/linux/fs/9p/vfs_super.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  *  linux/fs/9p/vfs_super.c
3  *
4  * This file contians superblock ops for 9P2000. It is intended that
5  * you mount this file system on directories.
6  *
7  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or
13  *  (at your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful,
16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *  GNU General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License
21  *  along with this program; if not, write to:
22  *  Free Software Foundation
23  *  51 Franklin Street, Fifth Floor
24  *  Boston, MA  02111-1301  USA
25  *
26  */
27 
28 #include <linux/kernel.h>
29 #include <linux/config.h>
30 #include <linux/module.h>
31 #include <linux/errno.h>
32 #include <linux/fs.h>
33 #include <linux/file.h>
34 #include <linux/stat.h>
35 #include <linux/string.h>
36 #include <linux/smp_lock.h>
37 #include <linux/inet.h>
38 #include <linux/pagemap.h>
39 #include <linux/seq_file.h>
40 #include <linux/mount.h>
41 #include <linux/idr.h>
42 
43 #include "debug.h"
44 #include "v9fs.h"
45 #include "9p.h"
46 #include "v9fs_vfs.h"
47 #include "conv.h"
48 #include "fid.h"
49 
50 static void v9fs_clear_inode(struct inode *);
51 static struct super_operations v9fs_super_ops;
52 
53 /**
54  * v9fs_clear_inode - release an inode
55  * @inode: inode to release
56  *
57  */
58 
59 static void v9fs_clear_inode(struct inode *inode)
60 {
61 	filemap_fdatawrite(inode->i_mapping);
62 }
63 
64 /**
65  * v9fs_set_super - set the superblock
66  * @s: super block
67  * @data: file system specific data
68  *
69  */
70 
71 static int v9fs_set_super(struct super_block *s, void *data)
72 {
73 	s->s_fs_info = data;
74 	return set_anon_super(s, data);
75 }
76 
77 /**
78  * v9fs_fill_super - populate superblock with info
79  * @sb: superblock
80  * @v9ses: session information
81  *
82  */
83 
84 static void
85 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
86 		int flags)
87 {
88 	sb->s_maxbytes = MAX_LFS_FILESIZE;
89 	sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
90 	sb->s_blocksize = 1 << sb->s_blocksize_bits;
91 	sb->s_magic = V9FS_MAGIC;
92 	sb->s_op = &v9fs_super_ops;
93 
94 	sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
95 	    MS_NODIRATIME | MS_NOATIME;
96 }
97 
98 /**
99  * v9fs_get_sb - mount a superblock
100  * @fs_type: file system type
101  * @flags: mount flags
102  * @dev_name: device name that was mounted
103  * @data: mount options
104  *
105  */
106 
107 static struct super_block *v9fs_get_sb(struct file_system_type
108 				       *fs_type, int flags,
109 				       const char *dev_name, void *data)
110 {
111 	struct super_block *sb = NULL;
112 	struct v9fs_fcall *fcall = NULL;
113 	struct inode *inode = NULL;
114 	struct dentry *root = NULL;
115 	struct v9fs_session_info *v9ses = NULL;
116 	struct v9fs_fid *root_fid = NULL;
117 	int mode = S_IRWXUGO | S_ISVTX;
118 	uid_t uid = current->fsuid;
119 	gid_t gid = current->fsgid;
120 	int stat_result = 0;
121 	int newfid = 0;
122 	int retval = 0;
123 
124 	dprintk(DEBUG_VFS, " \n");
125 
126 	v9ses = kcalloc(1, sizeof(struct v9fs_session_info), GFP_KERNEL);
127 	if (!v9ses)
128 		return ERR_PTR(-ENOMEM);
129 
130 	if ((newfid = v9fs_session_init(v9ses, dev_name, data)) < 0) {
131 		dprintk(DEBUG_ERROR, "problem initiating session\n");
132 		return ERR_PTR(newfid);
133 	}
134 
135 	sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
136 
137 	v9fs_fill_super(sb, v9ses, flags);
138 
139 	inode = v9fs_get_inode(sb, S_IFDIR | mode);
140 	if (IS_ERR(inode)) {
141 		retval = PTR_ERR(inode);
142 		goto put_back_sb;
143 	}
144 
145 	inode->i_uid = uid;
146 	inode->i_gid = gid;
147 
148 	root = d_alloc_root(inode);
149 
150 	if (!root) {
151 		retval = -ENOMEM;
152 		goto put_back_sb;
153 	}
154 
155 	sb->s_root = root;
156 
157 	stat_result = v9fs_t_stat(v9ses, newfid, &fcall);
158 	if (stat_result < 0) {
159 		dprintk(DEBUG_ERROR, "stat error\n");
160 		v9fs_t_clunk(v9ses, newfid, NULL);
161 		v9fs_put_idpool(newfid, &v9ses->fidpool);
162 	} else {
163 		/* Setup the Root Inode */
164 		root_fid = v9fs_fid_create(root, v9ses, newfid, 0);
165 		if (root_fid == NULL) {
166 			retval = -ENOMEM;
167 			goto put_back_sb;
168 		}
169 
170 		root_fid->qid = fcall->params.rstat.stat->qid;
171 		root->d_inode->i_ino =
172 		    v9fs_qid2ino(&fcall->params.rstat.stat->qid);
173 		v9fs_mistat2inode(fcall->params.rstat.stat, root->d_inode, sb);
174 	}
175 
176 	kfree(fcall);
177 
178 	if (stat_result < 0) {
179 		retval = stat_result;
180 		goto put_back_sb;
181 	}
182 
183 	return sb;
184 
185 put_back_sb:
186 	/* deactivate_super calls v9fs_kill_super which will frees the rest */
187 	up_write(&sb->s_umount);
188 	deactivate_super(sb);
189 	return ERR_PTR(retval);
190 }
191 
192 /**
193  * v9fs_kill_super - Kill Superblock
194  * @s: superblock
195  *
196  */
197 
198 static void v9fs_kill_super(struct super_block *s)
199 {
200 	struct v9fs_session_info *v9ses = s->s_fs_info;
201 
202 	dprintk(DEBUG_VFS, " %p\n", s);
203 
204 	v9fs_dentry_release(s->s_root);	/* clunk root */
205 
206 	kill_anon_super(s);
207 
208 	v9fs_session_close(v9ses);
209 	kfree(v9ses);
210 	dprintk(DEBUG_VFS, "exiting kill_super\n");
211 }
212 
213 /**
214  * v9fs_show_options - Show mount options in /proc/mounts
215  * @m: seq_file to write to
216  * @mnt: mount descriptor
217  *
218  */
219 
220 static int v9fs_show_options(struct seq_file *m, struct vfsmount *mnt)
221 {
222 	struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;
223 
224 	if (v9ses->debug != 0)
225 		seq_printf(m, ",debug=%u", v9ses->debug);
226 	if (v9ses->port != V9FS_PORT)
227 		seq_printf(m, ",port=%u", v9ses->port);
228 	if (v9ses->maxdata != 9000)
229 		seq_printf(m, ",msize=%u", v9ses->maxdata);
230 	if (v9ses->afid != ~0)
231 		seq_printf(m, ",afid=%u", v9ses->afid);
232 	if (v9ses->proto == PROTO_UNIX)
233 		seq_puts(m, ",proto=unix");
234 	if (v9ses->extended == 0)
235 		seq_puts(m, ",noextend");
236 	if (v9ses->nodev == 1)
237 		seq_puts(m, ",nodevmap");
238 	seq_printf(m, ",name=%s", v9ses->name);
239 	seq_printf(m, ",aname=%s", v9ses->remotename);
240 	seq_printf(m, ",uid=%u", v9ses->uid);
241 	seq_printf(m, ",gid=%u", v9ses->gid);
242 	return 0;
243 }
244 
245 static void
246 v9fs_umount_begin(struct super_block *sb)
247 {
248 	struct v9fs_session_info *v9ses = sb->s_fs_info;
249 
250 	v9fs_session_cancel(v9ses);
251 }
252 
253 static struct super_operations v9fs_super_ops = {
254 	.statfs = simple_statfs,
255 	.clear_inode = v9fs_clear_inode,
256 	.show_options = v9fs_show_options,
257 	.umount_begin = v9fs_umount_begin,
258 };
259 
260 struct file_system_type v9fs_fs_type = {
261 	.name = "9P",
262 	.get_sb = v9fs_get_sb,
263 	.kill_sb = v9fs_kill_super,
264 	.owner = THIS_MODULE,
265 };
266