1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
5 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
6 */
7
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/errno.h>
11#include <linux/fs.h>
12#include <linux/file.h>
13#include <linux/stat.h>
14#include <linux/string.h>
15#include <linux/pagemap.h>
16#include <linux/mount.h>
17#include <linux/sched.h>
18#include <linux/slab.h>
19#include <linux/statfs.h>
20#include <linux/magic.h>
21#include <linux/fscache.h>
22#include <net/9p/9p.h>
23#include <net/9p/client.h>
24
25#include "v9fs.h"
26#include "v9fs_vfs.h"
27#include "fid.h"
28#include "xattr.h"
29#include "acl.h"
30
31static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
32
33/**
34 * v9fs_set_super - set the superblock
35 * @s: super block
36 * @data: file system specific data
37 *
38 */
39
40static int v9fs_set_super(struct super_block *s, void *data)
41{
42	s->s_fs_info = data;
43	return set_anon_super(s, data);
44}
45
46/**
47 * v9fs_fill_super - populate superblock with info
48 * @sb: superblock
49 * @v9ses: session information
50 * @flags: flags propagated from v9fs_mount()
51 *
52 */
53
54static int
55v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
56		int flags)
57{
58	int ret;
59
60	sb->s_maxbytes = MAX_LFS_FILESIZE;
61	sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
62	sb->s_blocksize = 1 << sb->s_blocksize_bits;
63	sb->s_magic = V9FS_MAGIC;
64	if (v9fs_proto_dotl(v9ses)) {
65		sb->s_op = &v9fs_super_ops_dotl;
66		if (!(v9ses->flags & V9FS_NO_XATTR))
67			sb->s_xattr = v9fs_xattr_handlers;
68	} else {
69		sb->s_op = &v9fs_super_ops;
70		sb->s_time_max = U32_MAX;
71	}
72
73	sb->s_time_min = 0;
74
75	ret = super_setup_bdi(sb);
76	if (ret)
77		return ret;
78
79	if (!v9ses->cache) {
80		sb->s_bdi->ra_pages = 0;
81		sb->s_bdi->io_pages = 0;
82	} else {
83		sb->s_bdi->ra_pages = v9ses->maxdata >> PAGE_SHIFT;
84		sb->s_bdi->io_pages = v9ses->maxdata >> PAGE_SHIFT;
85	}
86
87	sb->s_flags |= SB_ACTIVE;
88
89#ifdef CONFIG_9P_FS_POSIX_ACL
90	if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
91		sb->s_flags |= SB_POSIXACL;
92#endif
93
94	return 0;
95}
96
97/**
98 * v9fs_mount - mount a superblock
99 * @fs_type: file system type
100 * @flags: mount flags
101 * @dev_name: device name that was mounted
102 * @data: mount options
103 *
104 */
105
106static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
107		       const char *dev_name, void *data)
108{
109	struct super_block *sb = NULL;
110	struct inode *inode = NULL;
111	struct dentry *root = NULL;
112	struct v9fs_session_info *v9ses = NULL;
113	struct p9_fid *fid;
114	int retval = 0;
115
116	p9_debug(P9_DEBUG_VFS, "\n");
117
118	v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
119	if (!v9ses)
120		return ERR_PTR(-ENOMEM);
121
122	fid = v9fs_session_init(v9ses, dev_name, data);
123	if (IS_ERR(fid)) {
124		retval = PTR_ERR(fid);
125		goto free_session;
126	}
127
128	sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
129	if (IS_ERR(sb)) {
130		retval = PTR_ERR(sb);
131		goto clunk_fid;
132	}
133	retval = v9fs_fill_super(sb, v9ses, flags);
134	if (retval)
135		goto release_sb;
136
137	if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
138		sb->s_d_op = &v9fs_cached_dentry_operations;
139	else
140		sb->s_d_op = &v9fs_dentry_operations;
141
142	inode = v9fs_get_inode_from_fid(v9ses, fid, sb, true);
143	if (IS_ERR(inode)) {
144		retval = PTR_ERR(inode);
145		goto release_sb;
146	}
147
148	root = d_make_root(inode);
149	if (!root) {
150		retval = -ENOMEM;
151		goto release_sb;
152	}
153	sb->s_root = root;
154	retval = v9fs_get_acl(inode, fid);
155	if (retval)
156		goto release_sb;
157	v9fs_fid_add(root, &fid);
158
159	p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
160	return dget(sb->s_root);
161
162clunk_fid:
163	p9_fid_put(fid);
164	v9fs_session_close(v9ses);
165free_session:
166	kfree(v9ses);
167	return ERR_PTR(retval);
168
169release_sb:
170	/*
171	 * we will do the session_close and root dentry release
172	 * in the below call. But we need to clunk fid, because we haven't
173	 * attached the fid to dentry so it won't get clunked
174	 * automatically.
175	 */
176	p9_fid_put(fid);
177	deactivate_locked_super(sb);
178	return ERR_PTR(retval);
179}
180
181/**
182 * v9fs_kill_super - Kill Superblock
183 * @s: superblock
184 *
185 */
186
187static void v9fs_kill_super(struct super_block *s)
188{
189	struct v9fs_session_info *v9ses = s->s_fs_info;
190
191	p9_debug(P9_DEBUG_VFS, " %p\n", s);
192
193	kill_anon_super(s);
194
195	v9fs_session_cancel(v9ses);
196	v9fs_session_close(v9ses);
197	kfree(v9ses);
198	s->s_fs_info = NULL;
199	p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
200}
201
202static void
203v9fs_umount_begin(struct super_block *sb)
204{
205	struct v9fs_session_info *v9ses;
206
207	v9ses = sb->s_fs_info;
208	v9fs_session_begin_cancel(v9ses);
209}
210
211static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
212{
213	struct v9fs_session_info *v9ses;
214	struct p9_fid *fid;
215	struct p9_rstatfs rs;
216	int res;
217
218	fid = v9fs_fid_lookup(dentry);
219	if (IS_ERR(fid)) {
220		res = PTR_ERR(fid);
221		goto done;
222	}
223
224	v9ses = v9fs_dentry2v9ses(dentry);
225	if (v9fs_proto_dotl(v9ses)) {
226		res = p9_client_statfs(fid, &rs);
227		if (res == 0) {
228			buf->f_type = rs.type;
229			buf->f_bsize = rs.bsize;
230			buf->f_blocks = rs.blocks;
231			buf->f_bfree = rs.bfree;
232			buf->f_bavail = rs.bavail;
233			buf->f_files = rs.files;
234			buf->f_ffree = rs.ffree;
235			buf->f_fsid = u64_to_fsid(rs.fsid);
236			buf->f_namelen = rs.namelen;
237		}
238		if (res != -ENOSYS)
239			goto done;
240	}
241	res = simple_statfs(dentry, buf);
242done:
243	p9_fid_put(fid);
244	return res;
245}
246
247static int v9fs_drop_inode(struct inode *inode)
248{
249	struct v9fs_session_info *v9ses;
250
251	v9ses = v9fs_inode2v9ses(inode);
252	if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
253		return generic_drop_inode(inode);
254	/*
255	 * in case of non cached mode always drop the
256	 * inode because we want the inode attribute
257	 * to always match that on the server.
258	 */
259	return 1;
260}
261
262static int v9fs_write_inode(struct inode *inode,
263			    struct writeback_control *wbc)
264{
265	/*
266	 * send an fsync request to server irrespective of
267	 * wbc->sync_mode.
268	 */
269	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
270	return netfs_unpin_writeback(inode, wbc);
271}
272
273static int v9fs_write_inode_dotl(struct inode *inode,
274				 struct writeback_control *wbc)
275{
276
277	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
278
279	return netfs_unpin_writeback(inode, wbc);
280}
281
282static const struct super_operations v9fs_super_ops = {
283	.alloc_inode = v9fs_alloc_inode,
284	.free_inode = v9fs_free_inode,
285	.statfs = simple_statfs,
286	.drop_inode = v9fs_drop_inode,
287	.evict_inode = v9fs_evict_inode,
288	.show_options = v9fs_show_options,
289	.umount_begin = v9fs_umount_begin,
290	.write_inode = v9fs_write_inode,
291};
292
293static const struct super_operations v9fs_super_ops_dotl = {
294	.alloc_inode = v9fs_alloc_inode,
295	.free_inode = v9fs_free_inode,
296	.statfs = v9fs_statfs,
297	.drop_inode = v9fs_drop_inode,
298	.evict_inode = v9fs_evict_inode,
299	.show_options = v9fs_show_options,
300	.umount_begin = v9fs_umount_begin,
301	.write_inode = v9fs_write_inode_dotl,
302};
303
304struct file_system_type v9fs_fs_type = {
305	.name = "9p",
306	.mount = v9fs_mount,
307	.kill_sb = v9fs_kill_super,
308	.owner = THIS_MODULE,
309	.fs_flags = FS_RENAME_DOES_D_MOVE,
310};
311MODULE_ALIAS_FS("9p");
312