xref: /openbmc/linux/fs/9p/vfs_super.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 version 2
12  *  as published by the Free Software Foundation.
13  *
14  *  This program is distributed in the hope that it will be useful,
15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  *  GNU General Public License for more details.
18  *
19  *  You should have received a copy of the GNU General Public License
20  *  along with this program; if not, write to:
21  *  Free Software Foundation
22  *  51 Franklin Street, Fifth Floor
23  *  Boston, MA  02111-1301  USA
24  *
25  */
26 
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/file.h>
32 #include <linux/stat.h>
33 #include <linux/string.h>
34 #include <linux/inet.h>
35 #include <linux/pagemap.h>
36 #include <linux/seq_file.h>
37 #include <linux/mount.h>
38 #include <linux/idr.h>
39 
40 #include "debug.h"
41 #include "v9fs.h"
42 #include "9p.h"
43 #include "v9fs_vfs.h"
44 #include "fid.h"
45 
46 static void v9fs_clear_inode(struct inode *);
47 static const struct super_operations v9fs_super_ops;
48 
49 /**
50  * v9fs_clear_inode - release an inode
51  * @inode: inode to release
52  *
53  */
54 
55 static void v9fs_clear_inode(struct inode *inode)
56 {
57 	filemap_fdatawrite(inode->i_mapping);
58 }
59 
60 /**
61  * v9fs_set_super - set the superblock
62  * @s: super block
63  * @data: file system specific data
64  *
65  */
66 
67 static int v9fs_set_super(struct super_block *s, void *data)
68 {
69 	s->s_fs_info = data;
70 	return set_anon_super(s, data);
71 }
72 
73 /**
74  * v9fs_fill_super - populate superblock with info
75  * @sb: superblock
76  * @v9ses: session information
77  *
78  */
79 
80 static void
81 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
82 		int flags)
83 {
84 	sb->s_maxbytes = MAX_LFS_FILESIZE;
85 	sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
86 	sb->s_blocksize = 1 << sb->s_blocksize_bits;
87 	sb->s_magic = V9FS_MAGIC;
88 	sb->s_op = &v9fs_super_ops;
89 
90 	sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
91 	    MS_NOATIME;
92 }
93 
94 /**
95  * v9fs_get_sb - mount a superblock
96  * @fs_type: file system type
97  * @flags: mount flags
98  * @dev_name: device name that was mounted
99  * @data: mount options
100  * @mnt: mountpoint record to be instantiated
101  *
102  */
103 
104 static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
105 		       const char *dev_name, void *data,
106 		       struct vfsmount *mnt)
107 {
108 	struct super_block *sb = NULL;
109 	struct v9fs_fcall *fcall = NULL;
110 	struct inode *inode = NULL;
111 	struct dentry *root = NULL;
112 	struct v9fs_session_info *v9ses = NULL;
113 	struct v9fs_fid *root_fid = NULL;
114 	int mode = S_IRWXUGO | S_ISVTX;
115 	uid_t uid = current->fsuid;
116 	gid_t gid = current->fsgid;
117 	int stat_result = 0;
118 	int newfid = 0;
119 	int retval = 0;
120 
121 	dprintk(DEBUG_VFS, " \n");
122 
123 	v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
124 	if (!v9ses)
125 		return -ENOMEM;
126 
127 	if ((newfid = v9fs_session_init(v9ses, dev_name, data)) < 0) {
128 		dprintk(DEBUG_ERROR, "problem initiating session\n");
129 		retval = newfid;
130 		goto out_free_session;
131 	}
132 
133 	sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
134 	if (IS_ERR(sb)) {
135 		retval = PTR_ERR(sb);
136 		goto out_close_session;
137 	}
138 	v9fs_fill_super(sb, v9ses, flags);
139 
140 	inode = v9fs_get_inode(sb, S_IFDIR | mode);
141 	if (IS_ERR(inode)) {
142 		retval = PTR_ERR(inode);
143 		goto put_back_sb;
144 	}
145 
146 	inode->i_uid = uid;
147 	inode->i_gid = gid;
148 
149 	root = d_alloc_root(inode);
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);
161 	} else {
162 		/* Setup the Root Inode */
163 		root_fid = v9fs_fid_create(v9ses, newfid);
164 		if (root_fid == NULL) {
165 			retval = -ENOMEM;
166 			goto put_back_sb;
167 		}
168 
169 		retval = v9fs_fid_insert(root_fid, root);
170 		if (retval < 0) {
171 			kfree(fcall);
172 			goto put_back_sb;
173 		}
174 
175 		root_fid->qid = fcall->params.rstat.stat.qid;
176 		root->d_inode->i_ino =
177 		    v9fs_qid2ino(&fcall->params.rstat.stat.qid);
178 		v9fs_stat2inode(&fcall->params.rstat.stat, root->d_inode, sb);
179 	}
180 
181 	kfree(fcall);
182 
183 	if (stat_result < 0) {
184 		retval = stat_result;
185 		goto put_back_sb;
186 	}
187 
188 	return simple_set_mnt(mnt, sb);
189 
190 out_close_session:
191 	v9fs_session_close(v9ses);
192 out_free_session:
193 	kfree(v9ses);
194 	return retval;
195 
196 put_back_sb:
197 	/* deactivate_super calls v9fs_kill_super which will frees the rest */
198 	up_write(&sb->s_umount);
199 	deactivate_super(sb);
200 	return retval;
201 }
202 
203 /**
204  * v9fs_kill_super - Kill Superblock
205  * @s: superblock
206  *
207  */
208 
209 static void v9fs_kill_super(struct super_block *s)
210 {
211 	struct v9fs_session_info *v9ses = s->s_fs_info;
212 
213 	dprintk(DEBUG_VFS, " %p\n", s);
214 
215 	v9fs_dentry_release(s->s_root);	/* clunk root */
216 
217 	kill_anon_super(s);
218 
219 	v9fs_session_close(v9ses);
220 	kfree(v9ses);
221 	dprintk(DEBUG_VFS, "exiting kill_super\n");
222 }
223 
224 /**
225  * v9fs_show_options - Show mount options in /proc/mounts
226  * @m: seq_file to write to
227  * @mnt: mount descriptor
228  *
229  */
230 
231 static int v9fs_show_options(struct seq_file *m, struct vfsmount *mnt)
232 {
233 	struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;
234 
235 	if (v9ses->debug != 0)
236 		seq_printf(m, ",debug=%u", v9ses->debug);
237 	if (v9ses->port != V9FS_PORT)
238 		seq_printf(m, ",port=%u", v9ses->port);
239 	if (v9ses->maxdata != 9000)
240 		seq_printf(m, ",msize=%u", v9ses->maxdata);
241 	if (v9ses->afid != ~0)
242 		seq_printf(m, ",afid=%u", v9ses->afid);
243 	if (v9ses->proto == PROTO_UNIX)
244 		seq_puts(m, ",proto=unix");
245 	if (v9ses->extended == 0)
246 		seq_puts(m, ",noextend");
247 	if (v9ses->nodev == 1)
248 		seq_puts(m, ",nodevmap");
249 	seq_printf(m, ",name=%s", v9ses->name);
250 	seq_printf(m, ",aname=%s", v9ses->remotename);
251 	seq_printf(m, ",uid=%u", v9ses->uid);
252 	seq_printf(m, ",gid=%u", v9ses->gid);
253 	return 0;
254 }
255 
256 static void
257 v9fs_umount_begin(struct vfsmount *vfsmnt, int flags)
258 {
259 	struct v9fs_session_info *v9ses = vfsmnt->mnt_sb->s_fs_info;
260 
261 	if (flags & MNT_FORCE)
262 		v9fs_session_cancel(v9ses);
263 }
264 
265 static const struct super_operations v9fs_super_ops = {
266 	.statfs = simple_statfs,
267 	.clear_inode = v9fs_clear_inode,
268 	.show_options = v9fs_show_options,
269 	.umount_begin = v9fs_umount_begin,
270 };
271 
272 struct file_system_type v9fs_fs_type = {
273 	.name = "9p",
274 	.get_sb = v9fs_get_sb,
275 	.kill_sb = v9fs_kill_super,
276 	.owner = THIS_MODULE,
277 };
278