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
52static 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
61static 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
75static void
76v9fs_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_CACHE_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
113static 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		/*
134		 * we need to call session_close to tear down some
135		 * of the data structure setup by session_init
136		 */
137		goto close_session;
138	}
139
140	sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
141	if (IS_ERR(sb)) {
142		retval = PTR_ERR(sb);
143		goto clunk_fid;
144	}
145	v9fs_fill_super(sb, v9ses, flags, data);
146
147	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
148		sb->s_d_op = &v9fs_cached_dentry_operations;
149	else
150		sb->s_d_op = &v9fs_dentry_operations;
151
152	inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
153	if (IS_ERR(inode)) {
154		retval = PTR_ERR(inode);
155		goto release_sb;
156	}
157
158	root = d_make_root(inode);
159	if (!root) {
160		retval = -ENOMEM;
161		goto release_sb;
162	}
163	sb->s_root = root;
164	if (v9fs_proto_dotl(v9ses)) {
165		struct p9_stat_dotl *st = NULL;
166		st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
167		if (IS_ERR(st)) {
168			retval = PTR_ERR(st);
169			goto release_sb;
170		}
171		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
172		v9fs_stat2inode_dotl(st, d_inode(root));
173		kfree(st);
174	} else {
175		struct p9_wstat *st = NULL;
176		st = p9_client_stat(fid);
177		if (IS_ERR(st)) {
178			retval = PTR_ERR(st);
179			goto release_sb;
180		}
181
182		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
183		v9fs_stat2inode(st, d_inode(root), sb);
184
185		p9stat_free(st);
186		kfree(st);
187	}
188	retval = v9fs_get_acl(inode, fid);
189	if (retval)
190		goto release_sb;
191	v9fs_fid_add(root, fid);
192
193	p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
194	return dget(sb->s_root);
195
196clunk_fid:
197	p9_client_clunk(fid);
198close_session:
199	v9fs_session_close(v9ses);
200	kfree(v9ses);
201	return ERR_PTR(retval);
202
203release_sb:
204	/*
205	 * we will do the session_close and root dentry release
206	 * in the below call. But we need to clunk fid, because we haven't
207	 * attached the fid to dentry so it won't get clunked
208	 * automatically.
209	 */
210	p9_client_clunk(fid);
211	deactivate_locked_super(sb);
212	return ERR_PTR(retval);
213}
214
215/**
216 * v9fs_kill_super - Kill Superblock
217 * @s: superblock
218 *
219 */
220
221static void v9fs_kill_super(struct super_block *s)
222{
223	struct v9fs_session_info *v9ses = s->s_fs_info;
224
225	p9_debug(P9_DEBUG_VFS, " %p\n", s);
226
227	kill_anon_super(s);
228
229	v9fs_session_cancel(v9ses);
230	v9fs_session_close(v9ses);
231	kfree(v9ses);
232	s->s_fs_info = NULL;
233	p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
234}
235
236static void
237v9fs_umount_begin(struct super_block *sb)
238{
239	struct v9fs_session_info *v9ses;
240
241	v9ses = sb->s_fs_info;
242	v9fs_session_begin_cancel(v9ses);
243}
244
245static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
246{
247	struct v9fs_session_info *v9ses;
248	struct p9_fid *fid;
249	struct p9_rstatfs rs;
250	int res;
251
252	fid = v9fs_fid_lookup(dentry);
253	if (IS_ERR(fid)) {
254		res = PTR_ERR(fid);
255		goto done;
256	}
257
258	v9ses = v9fs_dentry2v9ses(dentry);
259	if (v9fs_proto_dotl(v9ses)) {
260		res = p9_client_statfs(fid, &rs);
261		if (res == 0) {
262			buf->f_type = rs.type;
263			buf->f_bsize = rs.bsize;
264			buf->f_blocks = rs.blocks;
265			buf->f_bfree = rs.bfree;
266			buf->f_bavail = rs.bavail;
267			buf->f_files = rs.files;
268			buf->f_ffree = rs.ffree;
269			buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
270			buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
271			buf->f_namelen = rs.namelen;
272		}
273		if (res != -ENOSYS)
274			goto done;
275	}
276	res = simple_statfs(dentry, buf);
277done:
278	return res;
279}
280
281static int v9fs_drop_inode(struct inode *inode)
282{
283	struct v9fs_session_info *v9ses;
284	v9ses = v9fs_inode2v9ses(inode);
285	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
286		return generic_drop_inode(inode);
287	/*
288	 * in case of non cached mode always drop the
289	 * the inode because we want the inode attribute
290	 * to always match that on the server.
291	 */
292	return 1;
293}
294
295static int v9fs_write_inode(struct inode *inode,
296			    struct writeback_control *wbc)
297{
298	int ret;
299	struct p9_wstat wstat;
300	struct v9fs_inode *v9inode;
301	/*
302	 * send an fsync request to server irrespective of
303	 * wbc->sync_mode.
304	 */
305	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
306	v9inode = V9FS_I(inode);
307	if (!v9inode->writeback_fid)
308		return 0;
309	v9fs_blank_wstat(&wstat);
310
311	ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
312	if (ret < 0) {
313		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
314		return ret;
315	}
316	return 0;
317}
318
319static int v9fs_write_inode_dotl(struct inode *inode,
320				 struct writeback_control *wbc)
321{
322	int ret;
323	struct v9fs_inode *v9inode;
324	/*
325	 * send an fsync request to server irrespective of
326	 * wbc->sync_mode.
327	 */
328	v9inode = V9FS_I(inode);
329	p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
330		 __func__, inode, v9inode->writeback_fid);
331	if (!v9inode->writeback_fid)
332		return 0;
333
334	ret = p9_client_fsync(v9inode->writeback_fid, 0);
335	if (ret < 0) {
336		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
337		return ret;
338	}
339	return 0;
340}
341
342static const struct super_operations v9fs_super_ops = {
343	.alloc_inode = v9fs_alloc_inode,
344	.destroy_inode = v9fs_destroy_inode,
345	.statfs = simple_statfs,
346	.evict_inode = v9fs_evict_inode,
347	.show_options = generic_show_options,
348	.umount_begin = v9fs_umount_begin,
349	.write_inode = v9fs_write_inode,
350};
351
352static const struct super_operations v9fs_super_ops_dotl = {
353	.alloc_inode = v9fs_alloc_inode,
354	.destroy_inode = v9fs_destroy_inode,
355	.statfs = v9fs_statfs,
356	.drop_inode = v9fs_drop_inode,
357	.evict_inode = v9fs_evict_inode,
358	.show_options = generic_show_options,
359	.umount_begin = v9fs_umount_begin,
360	.write_inode = v9fs_write_inode_dotl,
361};
362
363struct file_system_type v9fs_fs_type = {
364	.name = "9p",
365	.mount = v9fs_mount,
366	.kill_sb = v9fs_kill_super,
367	.owner = THIS_MODULE,
368	.fs_flags = FS_RENAME_DOES_D_MOVE,
369};
370MODULE_ALIAS_FS("9p");
371