1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/fs/9p/vfs_super.c
4 *
5 * This file contians superblock ops for 9P2000. It is intended that
6 * you mount this file system on directories.
7 *
8 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
9 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/fs.h>
16 #include <linux/file.h>
17 #include <linux/stat.h>
18 #include <linux/string.h>
19 #include <linux/inet.h>
20 #include <linux/pagemap.h>
21 #include <linux/mount.h>
22 #include <linux/idr.h>
23 #include <linux/sched.h>
24 #include <linux/slab.h>
25 #include <linux/statfs.h>
26 #include <linux/magic.h>
27 #include <net/9p/9p.h>
28 #include <net/9p/client.h>
29
30 #include "v9fs.h"
31 #include "v9fs_vfs.h"
32 #include "fid.h"
33 #include "xattr.h"
34 #include "acl.h"
35
36 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
37
38 /**
39 * v9fs_set_super - set the superblock
40 * @s: super block
41 * @data: file system specific data
42 *
43 */
44
v9fs_set_super(struct super_block * s,void * data)45 static int v9fs_set_super(struct super_block *s, void *data)
46 {
47 s->s_fs_info = data;
48 return set_anon_super(s, data);
49 }
50
51 /**
52 * v9fs_fill_super - populate superblock with info
53 * @sb: superblock
54 * @v9ses: session information
55 * @flags: flags propagated from v9fs_mount()
56 *
57 */
58
59 static int
v9fs_fill_super(struct super_block * sb,struct v9fs_session_info * v9ses,int flags)60 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
61 int flags)
62 {
63 int ret;
64
65 sb->s_maxbytes = MAX_LFS_FILESIZE;
66 sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
67 sb->s_blocksize = 1 << sb->s_blocksize_bits;
68 sb->s_magic = V9FS_MAGIC;
69 if (v9fs_proto_dotl(v9ses)) {
70 sb->s_op = &v9fs_super_ops_dotl;
71 sb->s_xattr = v9fs_xattr_handlers;
72 } else {
73 sb->s_op = &v9fs_super_ops;
74 sb->s_time_max = U32_MAX;
75 }
76
77 sb->s_time_min = 0;
78
79 ret = super_setup_bdi(sb);
80 if (ret)
81 return ret;
82
83 if (!v9ses->cache) {
84 sb->s_bdi->ra_pages = 0;
85 sb->s_bdi->io_pages = 0;
86 }
87
88 sb->s_flags |= SB_ACTIVE | SB_DIRSYNC;
89 if (!v9ses->cache)
90 sb->s_flags |= SB_SYNCHRONOUS;
91
92 #ifdef CONFIG_9P_FS_POSIX_ACL
93 if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
94 sb->s_flags |= SB_POSIXACL;
95 #endif
96
97 return 0;
98 }
99
100 /**
101 * v9fs_mount - mount a superblock
102 * @fs_type: file system type
103 * @flags: mount flags
104 * @dev_name: device name that was mounted
105 * @data: mount options
106 *
107 */
108
v9fs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)109 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
110 const char *dev_name, void *data)
111 {
112 struct super_block *sb = NULL;
113 struct inode *inode = NULL;
114 struct dentry *root = NULL;
115 struct v9fs_session_info *v9ses = NULL;
116 umode_t mode = S_IRWXUGO | S_ISVTX;
117 struct p9_fid *fid;
118 int retval = 0;
119
120 p9_debug(P9_DEBUG_VFS, "\n");
121
122 v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
123 if (!v9ses)
124 return ERR_PTR(-ENOMEM);
125
126 fid = v9fs_session_init(v9ses, dev_name, data);
127 if (IS_ERR(fid)) {
128 retval = PTR_ERR(fid);
129 goto free_session;
130 }
131
132 sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
133 if (IS_ERR(sb)) {
134 retval = PTR_ERR(sb);
135 goto clunk_fid;
136 }
137 retval = v9fs_fill_super(sb, v9ses, flags);
138 if (retval)
139 goto release_sb;
140
141 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
142 sb->s_d_op = &v9fs_cached_dentry_operations;
143 else
144 sb->s_d_op = &v9fs_dentry_operations;
145
146 inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
147 if (IS_ERR(inode)) {
148 retval = PTR_ERR(inode);
149 goto release_sb;
150 }
151
152 root = d_make_root(inode);
153 if (!root) {
154 retval = -ENOMEM;
155 goto release_sb;
156 }
157 sb->s_root = root;
158 if (v9fs_proto_dotl(v9ses)) {
159 struct p9_stat_dotl *st = NULL;
160 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
161 if (IS_ERR(st)) {
162 retval = PTR_ERR(st);
163 goto release_sb;
164 }
165 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
166 v9fs_stat2inode_dotl(st, d_inode(root), 0);
167 kfree(st);
168 } else {
169 struct p9_wstat *st = NULL;
170 st = p9_client_stat(fid);
171 if (IS_ERR(st)) {
172 retval = PTR_ERR(st);
173 goto release_sb;
174 }
175
176 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
177 v9fs_stat2inode(st, d_inode(root), sb, 0);
178
179 p9stat_free(st);
180 kfree(st);
181 }
182 retval = v9fs_get_acl(inode, fid);
183 if (retval)
184 goto release_sb;
185 v9fs_fid_add(root, fid);
186
187 p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
188 return dget(sb->s_root);
189
190 clunk_fid:
191 p9_client_clunk(fid);
192 v9fs_session_close(v9ses);
193 free_session:
194 kfree(v9ses);
195 return ERR_PTR(retval);
196
197 release_sb:
198 /*
199 * we will do the session_close and root dentry release
200 * in the below call. But we need to clunk fid, because we haven't
201 * attached the fid to dentry so it won't get clunked
202 * automatically.
203 */
204 p9_client_clunk(fid);
205 deactivate_locked_super(sb);
206 return ERR_PTR(retval);
207 }
208
209 /**
210 * v9fs_kill_super - Kill Superblock
211 * @s: superblock
212 *
213 */
214
v9fs_kill_super(struct super_block * s)215 static void v9fs_kill_super(struct super_block *s)
216 {
217 struct v9fs_session_info *v9ses = s->s_fs_info;
218
219 p9_debug(P9_DEBUG_VFS, " %p\n", s);
220
221 kill_anon_super(s);
222
223 v9fs_session_cancel(v9ses);
224 v9fs_session_close(v9ses);
225 kfree(v9ses);
226 s->s_fs_info = NULL;
227 p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
228 }
229
230 static void
v9fs_umount_begin(struct super_block * sb)231 v9fs_umount_begin(struct super_block *sb)
232 {
233 struct v9fs_session_info *v9ses;
234
235 v9ses = sb->s_fs_info;
236 v9fs_session_begin_cancel(v9ses);
237 }
238
v9fs_statfs(struct dentry * dentry,struct kstatfs * buf)239 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
240 {
241 struct v9fs_session_info *v9ses;
242 struct p9_fid *fid;
243 struct p9_rstatfs rs;
244 int res;
245
246 fid = v9fs_fid_lookup(dentry);
247 if (IS_ERR(fid)) {
248 res = PTR_ERR(fid);
249 goto done;
250 }
251
252 v9ses = v9fs_dentry2v9ses(dentry);
253 if (v9fs_proto_dotl(v9ses)) {
254 res = p9_client_statfs(fid, &rs);
255 if (res == 0) {
256 buf->f_type = rs.type;
257 buf->f_bsize = rs.bsize;
258 buf->f_blocks = rs.blocks;
259 buf->f_bfree = rs.bfree;
260 buf->f_bavail = rs.bavail;
261 buf->f_files = rs.files;
262 buf->f_ffree = rs.ffree;
263 buf->f_fsid = u64_to_fsid(rs.fsid);
264 buf->f_namelen = rs.namelen;
265 }
266 if (res != -ENOSYS)
267 goto done;
268 }
269 res = simple_statfs(dentry, buf);
270 done:
271 return res;
272 }
273
v9fs_drop_inode(struct inode * inode)274 static int v9fs_drop_inode(struct inode *inode)
275 {
276 struct v9fs_session_info *v9ses;
277 v9ses = v9fs_inode2v9ses(inode);
278 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
279 return generic_drop_inode(inode);
280 /*
281 * in case of non cached mode always drop the
282 * the inode because we want the inode attribute
283 * to always match that on the server.
284 */
285 return 1;
286 }
287
v9fs_write_inode(struct inode * inode,struct writeback_control * wbc)288 static int v9fs_write_inode(struct inode *inode,
289 struct writeback_control *wbc)
290 {
291 int ret;
292 struct p9_wstat wstat;
293 struct v9fs_inode *v9inode;
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 v9inode = V9FS_I(inode);
300 if (!v9inode->writeback_fid)
301 return 0;
302 v9fs_blank_wstat(&wstat);
303
304 ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
305 if (ret < 0) {
306 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
307 return ret;
308 }
309 return 0;
310 }
311
v9fs_write_inode_dotl(struct inode * inode,struct writeback_control * wbc)312 static int v9fs_write_inode_dotl(struct inode *inode,
313 struct writeback_control *wbc)
314 {
315 int ret;
316 struct v9fs_inode *v9inode;
317 /*
318 * send an fsync request to server irrespective of
319 * wbc->sync_mode.
320 */
321 v9inode = V9FS_I(inode);
322 p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
323 __func__, inode, v9inode->writeback_fid);
324 if (!v9inode->writeback_fid)
325 return 0;
326
327 ret = p9_client_fsync(v9inode->writeback_fid, 0);
328 if (ret < 0) {
329 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
330 return ret;
331 }
332 return 0;
333 }
334
335 static const struct super_operations v9fs_super_ops = {
336 .alloc_inode = v9fs_alloc_inode,
337 .free_inode = v9fs_free_inode,
338 .statfs = simple_statfs,
339 .evict_inode = v9fs_evict_inode,
340 .show_options = v9fs_show_options,
341 .umount_begin = v9fs_umount_begin,
342 .write_inode = v9fs_write_inode,
343 };
344
345 static const struct super_operations v9fs_super_ops_dotl = {
346 .alloc_inode = v9fs_alloc_inode,
347 .free_inode = v9fs_free_inode,
348 .statfs = v9fs_statfs,
349 .drop_inode = v9fs_drop_inode,
350 .evict_inode = v9fs_evict_inode,
351 .show_options = v9fs_show_options,
352 .umount_begin = v9fs_umount_begin,
353 .write_inode = v9fs_write_inode_dotl,
354 };
355
356 struct file_system_type v9fs_fs_type = {
357 .name = "9p",
358 .mount = v9fs_mount,
359 .kill_sb = v9fs_kill_super,
360 .owner = THIS_MODULE,
361 .fs_flags = FS_RENAME_DOES_D_MOVE,
362 };
363 MODULE_ALIAS_FS("9p");
364