xref: /openbmc/linux/fs/9p/vfs_super.c (revision 78700c0a)
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 #include <linux/sched.h>
40 #include <linux/slab.h>
41 #include <linux/statfs.h>
42 #include <linux/magic.h>
43 #include <net/9p/9p.h>
44 #include <net/9p/client.h>
45 
46 #include "v9fs.h"
47 #include "v9fs_vfs.h"
48 #include "fid.h"
49 #include "xattr.h"
50 #include "acl.h"
51 
52 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
53 
54 /**
55  * v9fs_set_super - set the superblock
56  * @s: super block
57  * @data: file system specific data
58  *
59  */
60 
61 static int v9fs_set_super(struct super_block *s, void *data)
62 {
63 	s->s_fs_info = data;
64 	return set_anon_super(s, data);
65 }
66 
67 /**
68  * v9fs_fill_super - populate superblock with info
69  * @sb: superblock
70  * @v9ses: session information
71  * @flags: flags propagated from v9fs_mount()
72  *
73  */
74 
75 static void
76 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
77 		int flags, void *data)
78 {
79 	sb->s_maxbytes = MAX_LFS_FILESIZE;
80 	sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
81 	sb->s_blocksize = 1 << sb->s_blocksize_bits;
82 	sb->s_magic = V9FS_MAGIC;
83 	if (v9fs_proto_dotl(v9ses)) {
84 		sb->s_op = &v9fs_super_ops_dotl;
85 		sb->s_xattr = v9fs_xattr_handlers;
86 	} else
87 		sb->s_op = &v9fs_super_ops;
88 	sb->s_bdi = &v9ses->bdi;
89 	if (v9ses->cache)
90 		sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024)/PAGE_SIZE;
91 
92 	sb->s_flags |= MS_ACTIVE | MS_DIRSYNC | MS_NOATIME;
93 	if (!v9ses->cache)
94 		sb->s_flags |= MS_SYNCHRONOUS;
95 
96 #ifdef CONFIG_9P_FS_POSIX_ACL
97 	if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
98 		sb->s_flags |= MS_POSIXACL;
99 #endif
100 
101 	save_mount_options(sb, data);
102 }
103 
104 /**
105  * v9fs_mount - mount a superblock
106  * @fs_type: file system type
107  * @flags: mount flags
108  * @dev_name: device name that was mounted
109  * @data: mount options
110  *
111  */
112 
113 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
114 		       const char *dev_name, void *data)
115 {
116 	struct super_block *sb = NULL;
117 	struct inode *inode = NULL;
118 	struct dentry *root = NULL;
119 	struct v9fs_session_info *v9ses = NULL;
120 	umode_t mode = S_IRWXUGO | S_ISVTX;
121 	struct p9_fid *fid;
122 	int retval = 0;
123 
124 	p9_debug(P9_DEBUG_VFS, "\n");
125 
126 	v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
127 	if (!v9ses)
128 		return ERR_PTR(-ENOMEM);
129 
130 	fid = v9fs_session_init(v9ses, dev_name, data);
131 	if (IS_ERR(fid)) {
132 		retval = PTR_ERR(fid);
133 		goto free_session;
134 	}
135 
136 	sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
137 	if (IS_ERR(sb)) {
138 		retval = PTR_ERR(sb);
139 		goto clunk_fid;
140 	}
141 	v9fs_fill_super(sb, v9ses, flags, data);
142 
143 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
144 		sb->s_d_op = &v9fs_cached_dentry_operations;
145 	else
146 		sb->s_d_op = &v9fs_dentry_operations;
147 
148 	inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
149 	if (IS_ERR(inode)) {
150 		retval = PTR_ERR(inode);
151 		goto release_sb;
152 	}
153 
154 	root = d_make_root(inode);
155 	if (!root) {
156 		retval = -ENOMEM;
157 		goto release_sb;
158 	}
159 	sb->s_root = root;
160 	if (v9fs_proto_dotl(v9ses)) {
161 		struct p9_stat_dotl *st = NULL;
162 		st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
163 		if (IS_ERR(st)) {
164 			retval = PTR_ERR(st);
165 			goto release_sb;
166 		}
167 		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
168 		v9fs_stat2inode_dotl(st, d_inode(root));
169 		kfree(st);
170 	} else {
171 		struct p9_wstat *st = NULL;
172 		st = p9_client_stat(fid);
173 		if (IS_ERR(st)) {
174 			retval = PTR_ERR(st);
175 			goto release_sb;
176 		}
177 
178 		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
179 		v9fs_stat2inode(st, d_inode(root), sb);
180 
181 		p9stat_free(st);
182 		kfree(st);
183 	}
184 	retval = v9fs_get_acl(inode, fid);
185 	if (retval)
186 		goto release_sb;
187 	v9fs_fid_add(root, fid);
188 
189 	p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
190 	return dget(sb->s_root);
191 
192 clunk_fid:
193 	p9_client_clunk(fid);
194 	v9fs_session_close(v9ses);
195 free_session:
196 	kfree(v9ses);
197 	return ERR_PTR(retval);
198 
199 release_sb:
200 	/*
201 	 * we will do the session_close and root dentry release
202 	 * in the below call. But we need to clunk fid, because we haven't
203 	 * attached the fid to dentry so it won't get clunked
204 	 * automatically.
205 	 */
206 	p9_client_clunk(fid);
207 	deactivate_locked_super(sb);
208 	return ERR_PTR(retval);
209 }
210 
211 /**
212  * v9fs_kill_super - Kill Superblock
213  * @s: superblock
214  *
215  */
216 
217 static void v9fs_kill_super(struct super_block *s)
218 {
219 	struct v9fs_session_info *v9ses = s->s_fs_info;
220 
221 	p9_debug(P9_DEBUG_VFS, " %p\n", s);
222 
223 	kill_anon_super(s);
224 
225 	v9fs_session_cancel(v9ses);
226 	v9fs_session_close(v9ses);
227 	kfree(v9ses);
228 	s->s_fs_info = NULL;
229 	p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
230 }
231 
232 static void
233 v9fs_umount_begin(struct super_block *sb)
234 {
235 	struct v9fs_session_info *v9ses;
236 
237 	v9ses = sb->s_fs_info;
238 	v9fs_session_begin_cancel(v9ses);
239 }
240 
241 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
242 {
243 	struct v9fs_session_info *v9ses;
244 	struct p9_fid *fid;
245 	struct p9_rstatfs rs;
246 	int res;
247 
248 	fid = v9fs_fid_lookup(dentry);
249 	if (IS_ERR(fid)) {
250 		res = PTR_ERR(fid);
251 		goto done;
252 	}
253 
254 	v9ses = v9fs_dentry2v9ses(dentry);
255 	if (v9fs_proto_dotl(v9ses)) {
256 		res = p9_client_statfs(fid, &rs);
257 		if (res == 0) {
258 			buf->f_type = rs.type;
259 			buf->f_bsize = rs.bsize;
260 			buf->f_blocks = rs.blocks;
261 			buf->f_bfree = rs.bfree;
262 			buf->f_bavail = rs.bavail;
263 			buf->f_files = rs.files;
264 			buf->f_ffree = rs.ffree;
265 			buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
266 			buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
267 			buf->f_namelen = rs.namelen;
268 		}
269 		if (res != -ENOSYS)
270 			goto done;
271 	}
272 	res = simple_statfs(dentry, buf);
273 done:
274 	return res;
275 }
276 
277 static int v9fs_drop_inode(struct inode *inode)
278 {
279 	struct v9fs_session_info *v9ses;
280 	v9ses = v9fs_inode2v9ses(inode);
281 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
282 		return generic_drop_inode(inode);
283 	/*
284 	 * in case of non cached mode always drop the
285 	 * the inode because we want the inode attribute
286 	 * to always match that on the server.
287 	 */
288 	return 1;
289 }
290 
291 static int v9fs_write_inode(struct inode *inode,
292 			    struct writeback_control *wbc)
293 {
294 	int ret;
295 	struct p9_wstat wstat;
296 	struct v9fs_inode *v9inode;
297 	/*
298 	 * send an fsync request to server irrespective of
299 	 * wbc->sync_mode.
300 	 */
301 	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
302 	v9inode = V9FS_I(inode);
303 	if (!v9inode->writeback_fid)
304 		return 0;
305 	v9fs_blank_wstat(&wstat);
306 
307 	ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
308 	if (ret < 0) {
309 		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
310 		return ret;
311 	}
312 	return 0;
313 }
314 
315 static int v9fs_write_inode_dotl(struct inode *inode,
316 				 struct writeback_control *wbc)
317 {
318 	int ret;
319 	struct v9fs_inode *v9inode;
320 	/*
321 	 * send an fsync request to server irrespective of
322 	 * wbc->sync_mode.
323 	 */
324 	v9inode = V9FS_I(inode);
325 	p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
326 		 __func__, inode, v9inode->writeback_fid);
327 	if (!v9inode->writeback_fid)
328 		return 0;
329 
330 	ret = p9_client_fsync(v9inode->writeback_fid, 0);
331 	if (ret < 0) {
332 		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
333 		return ret;
334 	}
335 	return 0;
336 }
337 
338 static const struct super_operations v9fs_super_ops = {
339 	.alloc_inode = v9fs_alloc_inode,
340 	.destroy_inode = v9fs_destroy_inode,
341 	.statfs = simple_statfs,
342 	.evict_inode = v9fs_evict_inode,
343 	.show_options = generic_show_options,
344 	.umount_begin = v9fs_umount_begin,
345 	.write_inode = v9fs_write_inode,
346 };
347 
348 static const struct super_operations v9fs_super_ops_dotl = {
349 	.alloc_inode = v9fs_alloc_inode,
350 	.destroy_inode = v9fs_destroy_inode,
351 	.statfs = v9fs_statfs,
352 	.drop_inode = v9fs_drop_inode,
353 	.evict_inode = v9fs_evict_inode,
354 	.show_options = generic_show_options,
355 	.umount_begin = v9fs_umount_begin,
356 	.write_inode = v9fs_write_inode_dotl,
357 };
358 
359 struct file_system_type v9fs_fs_type = {
360 	.name = "9p",
361 	.mount = v9fs_mount,
362 	.kill_sb = v9fs_kill_super,
363 	.owner = THIS_MODULE,
364 	.fs_flags = FS_RENAME_DOES_D_MOVE,
365 };
366 MODULE_ALIAS_FS("9p");
367