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 = VM_READAHEAD_PAGES;
85
86 sb->s_flags |= SB_ACTIVE | SB_DIRSYNC;
87 if (!v9ses->cache)
88 sb->s_flags |= SB_SYNCHRONOUS;
89
90 #ifdef CONFIG_9P_FS_POSIX_ACL
91 if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
92 sb->s_flags |= SB_POSIXACL;
93 #endif
94
95 return 0;
96 }
97
98 /**
99 * v9fs_mount - mount a superblock
100 * @fs_type: file system type
101 * @flags: mount flags
102 * @dev_name: device name that was mounted
103 * @data: mount options
104 *
105 */
106
v9fs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)107 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
108 const char *dev_name, void *data)
109 {
110 struct super_block *sb = NULL;
111 struct inode *inode = NULL;
112 struct dentry *root = NULL;
113 struct v9fs_session_info *v9ses = NULL;
114 umode_t mode = S_IRWXUGO | S_ISVTX;
115 struct p9_fid *fid;
116 int retval = 0;
117
118 p9_debug(P9_DEBUG_VFS, "\n");
119
120 v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
121 if (!v9ses)
122 return ERR_PTR(-ENOMEM);
123
124 fid = v9fs_session_init(v9ses, dev_name, data);
125 if (IS_ERR(fid)) {
126 retval = PTR_ERR(fid);
127 goto free_session;
128 }
129
130 sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
131 if (IS_ERR(sb)) {
132 retval = PTR_ERR(sb);
133 goto clunk_fid;
134 }
135 retval = v9fs_fill_super(sb, v9ses, flags);
136 if (retval)
137 goto release_sb;
138
139 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
140 sb->s_d_op = &v9fs_cached_dentry_operations;
141 else
142 sb->s_d_op = &v9fs_dentry_operations;
143
144 inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
145 if (IS_ERR(inode)) {
146 retval = PTR_ERR(inode);
147 goto release_sb;
148 }
149
150 root = d_make_root(inode);
151 if (!root) {
152 retval = -ENOMEM;
153 goto release_sb;
154 }
155 sb->s_root = root;
156 if (v9fs_proto_dotl(v9ses)) {
157 struct p9_stat_dotl *st = NULL;
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 st = p9_client_stat(fid);
169 if (IS_ERR(st)) {
170 retval = PTR_ERR(st);
171 goto release_sb;
172 }
173
174 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
175 v9fs_stat2inode(st, d_inode(root), sb, 0);
176
177 p9stat_free(st);
178 kfree(st);
179 }
180 retval = v9fs_get_acl(inode, fid);
181 if (retval)
182 goto release_sb;
183 v9fs_fid_add(root, fid);
184
185 p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
186 return dget(sb->s_root);
187
188 clunk_fid:
189 p9_client_clunk(fid);
190 v9fs_session_close(v9ses);
191 free_session:
192 kfree(v9ses);
193 return ERR_PTR(retval);
194
195 release_sb:
196 /*
197 * we will do the session_close and root dentry release
198 * in the below call. But we need to clunk fid, because we haven't
199 * attached the fid to dentry so it won't get clunked
200 * automatically.
201 */
202 p9_client_clunk(fid);
203 deactivate_locked_super(sb);
204 return ERR_PTR(retval);
205 }
206
207 /**
208 * v9fs_kill_super - Kill Superblock
209 * @s: superblock
210 *
211 */
212
v9fs_kill_super(struct super_block * s)213 static void v9fs_kill_super(struct super_block *s)
214 {
215 struct v9fs_session_info *v9ses = s->s_fs_info;
216
217 p9_debug(P9_DEBUG_VFS, " %p\n", s);
218
219 kill_anon_super(s);
220
221 v9fs_session_cancel(v9ses);
222 v9fs_session_close(v9ses);
223 kfree(v9ses);
224 s->s_fs_info = NULL;
225 p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
226 }
227
228 static void
v9fs_umount_begin(struct super_block * sb)229 v9fs_umount_begin(struct super_block *sb)
230 {
231 struct v9fs_session_info *v9ses;
232
233 v9ses = sb->s_fs_info;
234 v9fs_session_begin_cancel(v9ses);
235 }
236
v9fs_statfs(struct dentry * dentry,struct kstatfs * buf)237 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
238 {
239 struct v9fs_session_info *v9ses;
240 struct p9_fid *fid;
241 struct p9_rstatfs rs;
242 int res;
243
244 fid = v9fs_fid_lookup(dentry);
245 if (IS_ERR(fid)) {
246 res = PTR_ERR(fid);
247 goto done;
248 }
249
250 v9ses = v9fs_dentry2v9ses(dentry);
251 if (v9fs_proto_dotl(v9ses)) {
252 res = p9_client_statfs(fid, &rs);
253 if (res == 0) {
254 buf->f_type = rs.type;
255 buf->f_bsize = rs.bsize;
256 buf->f_blocks = rs.blocks;
257 buf->f_bfree = rs.bfree;
258 buf->f_bavail = rs.bavail;
259 buf->f_files = rs.files;
260 buf->f_ffree = rs.ffree;
261 buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
262 buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
263 buf->f_namelen = rs.namelen;
264 }
265 if (res != -ENOSYS)
266 goto done;
267 }
268 res = simple_statfs(dentry, buf);
269 done:
270 return res;
271 }
272
v9fs_drop_inode(struct inode * inode)273 static int v9fs_drop_inode(struct inode *inode)
274 {
275 struct v9fs_session_info *v9ses;
276 v9ses = v9fs_inode2v9ses(inode);
277 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
278 return generic_drop_inode(inode);
279 /*
280 * in case of non cached mode always drop the
281 * the inode because we want the inode attribute
282 * to always match that on the server.
283 */
284 return 1;
285 }
286
v9fs_write_inode(struct inode * inode,struct writeback_control * wbc)287 static int v9fs_write_inode(struct inode *inode,
288 struct writeback_control *wbc)
289 {
290 int ret;
291 struct p9_wstat wstat;
292 struct v9fs_inode *v9inode;
293 /*
294 * send an fsync request to server irrespective of
295 * wbc->sync_mode.
296 */
297 p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
298 v9inode = V9FS_I(inode);
299 if (!v9inode->writeback_fid)
300 return 0;
301 v9fs_blank_wstat(&wstat);
302
303 ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
304 if (ret < 0) {
305 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
306 return ret;
307 }
308 return 0;
309 }
310
v9fs_write_inode_dotl(struct inode * inode,struct writeback_control * wbc)311 static int v9fs_write_inode_dotl(struct inode *inode,
312 struct writeback_control *wbc)
313 {
314 int ret;
315 struct v9fs_inode *v9inode;
316 /*
317 * send an fsync request to server irrespective of
318 * wbc->sync_mode.
319 */
320 v9inode = V9FS_I(inode);
321 p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
322 __func__, inode, v9inode->writeback_fid);
323 if (!v9inode->writeback_fid)
324 return 0;
325
326 ret = p9_client_fsync(v9inode->writeback_fid, 0);
327 if (ret < 0) {
328 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
329 return ret;
330 }
331 return 0;
332 }
333
334 static const struct super_operations v9fs_super_ops = {
335 .alloc_inode = v9fs_alloc_inode,
336 .free_inode = v9fs_free_inode,
337 .statfs = simple_statfs,
338 .evict_inode = v9fs_evict_inode,
339 .show_options = v9fs_show_options,
340 .umount_begin = v9fs_umount_begin,
341 .write_inode = v9fs_write_inode,
342 };
343
344 static const struct super_operations v9fs_super_ops_dotl = {
345 .alloc_inode = v9fs_alloc_inode,
346 .free_inode = v9fs_free_inode,
347 .statfs = v9fs_statfs,
348 .drop_inode = v9fs_drop_inode,
349 .evict_inode = v9fs_evict_inode,
350 .show_options = v9fs_show_options,
351 .umount_begin = v9fs_umount_begin,
352 .write_inode = v9fs_write_inode_dotl,
353 };
354
355 struct file_system_type v9fs_fs_type = {
356 .name = "9p",
357 .mount = v9fs_mount,
358 .kill_sb = v9fs_kill_super,
359 .owner = THIS_MODULE,
360 .fs_flags = FS_RENAME_DOES_D_MOVE,
361 };
362 MODULE_ALIAS_FS("9p");
363