xref: /kernel/linux/linux-6.6/fs/9p/vfs_super.c (revision 62306a36) 
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	umode_t mode = 0777 | S_ISVTX;
114	struct p9_fid *fid;
115	int retval = 0;
116
117	p9_debug(P9_DEBUG_VFS, "\n");
118
119	v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
120	if (!v9ses)
121		return ERR_PTR(-ENOMEM);
122
123	fid = v9fs_session_init(v9ses, dev_name, data);
124	if (IS_ERR(fid)) {
125		retval = PTR_ERR(fid);
126		goto free_session;
127	}
128
129	sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
130	if (IS_ERR(sb)) {
131		retval = PTR_ERR(sb);
132		goto clunk_fid;
133	}
134	retval = v9fs_fill_super(sb, v9ses, flags);
135	if (retval)
136		goto release_sb;
137
138	if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
139		sb->s_d_op = &v9fs_cached_dentry_operations;
140	else
141		sb->s_d_op = &v9fs_dentry_operations;
142
143	inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
144	if (IS_ERR(inode)) {
145		retval = PTR_ERR(inode);
146		goto release_sb;
147	}
148
149	root = d_make_root(inode);
150	if (!root) {
151		retval = -ENOMEM;
152		goto release_sb;
153	}
154	sb->s_root = root;
155	if (v9fs_proto_dotl(v9ses)) {
156		struct p9_stat_dotl *st = NULL;
157
158		st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
159		if (IS_ERR(st)) {
160			retval = PTR_ERR(st);
161			goto release_sb;
162		}
163		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
164		v9fs_stat2inode_dotl(st, d_inode(root), 0);
165		kfree(st);
166	} else {
167		struct p9_wstat *st = NULL;
168
169		st = p9_client_stat(fid);
170		if (IS_ERR(st)) {
171			retval = PTR_ERR(st);
172			goto release_sb;
173		}
174
175		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
176		v9fs_stat2inode(st, d_inode(root), sb, 0);
177
178		p9stat_free(st);
179		kfree(st);
180	}
181	retval = v9fs_get_acl(inode, fid);
182	if (retval)
183		goto release_sb;
184	v9fs_fid_add(root, &fid);
185
186	p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
187	return dget(sb->s_root);
188
189clunk_fid:
190	p9_fid_put(fid);
191	v9fs_session_close(v9ses);
192free_session:
193	kfree(v9ses);
194	return ERR_PTR(retval);
195
196release_sb:
197	/*
198	 * we will do the session_close and root dentry release
199	 * in the below call. But we need to clunk fid, because we haven't
200	 * attached the fid to dentry so it won't get clunked
201	 * automatically.
202	 */
203	p9_fid_put(fid);
204	deactivate_locked_super(sb);
205	return ERR_PTR(retval);
206}
207
208/**
209 * v9fs_kill_super - Kill Superblock
210 * @s: superblock
211 *
212 */
213
214static void v9fs_kill_super(struct super_block *s)
215{
216	struct v9fs_session_info *v9ses = s->s_fs_info;
217
218	p9_debug(P9_DEBUG_VFS, " %p\n", s);
219
220	kill_anon_super(s);
221
222	v9fs_session_cancel(v9ses);
223	v9fs_session_close(v9ses);
224	kfree(v9ses);
225	s->s_fs_info = NULL;
226	p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
227}
228
229static void
230v9fs_umount_begin(struct super_block *sb)
231{
232	struct v9fs_session_info *v9ses;
233
234	v9ses = sb->s_fs_info;
235	v9fs_session_begin_cancel(v9ses);
236}
237
238static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
239{
240	struct v9fs_session_info *v9ses;
241	struct p9_fid *fid;
242	struct p9_rstatfs rs;
243	int res;
244
245	fid = v9fs_fid_lookup(dentry);
246	if (IS_ERR(fid)) {
247		res = PTR_ERR(fid);
248		goto done;
249	}
250
251	v9ses = v9fs_dentry2v9ses(dentry);
252	if (v9fs_proto_dotl(v9ses)) {
253		res = p9_client_statfs(fid, &rs);
254		if (res == 0) {
255			buf->f_type = rs.type;
256			buf->f_bsize = rs.bsize;
257			buf->f_blocks = rs.blocks;
258			buf->f_bfree = rs.bfree;
259			buf->f_bavail = rs.bavail;
260			buf->f_files = rs.files;
261			buf->f_ffree = rs.ffree;
262			buf->f_fsid = u64_to_fsid(rs.fsid);
263			buf->f_namelen = rs.namelen;
264		}
265		if (res != -ENOSYS)
266			goto done;
267	}
268	res = simple_statfs(dentry, buf);
269done:
270	p9_fid_put(fid);
271	return res;
272}
273
274static int v9fs_drop_inode(struct inode *inode)
275{
276	struct v9fs_session_info *v9ses;
277
278	v9ses = v9fs_inode2v9ses(inode);
279	if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
280		return generic_drop_inode(inode);
281	/*
282	 * in case of non cached mode always drop the
283	 * inode because we want the inode attribute
284	 * to always match that on the server.
285	 */
286	return 1;
287}
288
289static int v9fs_write_inode(struct inode *inode,
290			    struct writeback_control *wbc)
291{
292	struct v9fs_inode *v9inode;
293
294	/*
295	 * send an fsync request to server irrespective of
296	 * wbc->sync_mode.
297	 */
298	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
299
300	v9inode = V9FS_I(inode);
301	fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
302
303	return 0;
304}
305
306static int v9fs_write_inode_dotl(struct inode *inode,
307				 struct writeback_control *wbc)
308{
309	struct v9fs_inode *v9inode;
310
311	v9inode = V9FS_I(inode);
312	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
313
314	fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
315
316	return 0;
317}
318
319static const struct super_operations v9fs_super_ops = {
320	.alloc_inode = v9fs_alloc_inode,
321	.free_inode = v9fs_free_inode,
322	.statfs = simple_statfs,
323	.evict_inode = v9fs_evict_inode,
324	.show_options = v9fs_show_options,
325	.umount_begin = v9fs_umount_begin,
326	.write_inode = v9fs_write_inode,
327};
328
329static const struct super_operations v9fs_super_ops_dotl = {
330	.alloc_inode = v9fs_alloc_inode,
331	.free_inode = v9fs_free_inode,
332	.statfs = v9fs_statfs,
333	.drop_inode = v9fs_drop_inode,
334	.evict_inode = v9fs_evict_inode,
335	.show_options = v9fs_show_options,
336	.umount_begin = v9fs_umount_begin,
337	.write_inode = v9fs_write_inode_dotl,
338};
339
340struct file_system_type v9fs_fs_type = {
341	.name = "9p",
342	.mount = v9fs_mount,
343	.kill_sb = v9fs_kill_super,
344	.owner = THIS_MODULE,
345	.fs_flags = FS_RENAME_DOES_D_MOVE,
346};
347MODULE_ALIAS_FS("9p");
348