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(x: 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(size: sizeof(struct v9fs_session_info), GFP_KERNEL);
120 if (!v9ses)
121 return ERR_PTR(error: -ENOMEM);
122
123 fid = v9fs_session_init(v9ses, dev_name, data);
124 if (IS_ERR(ptr: fid)) {
125 retval = PTR_ERR(ptr: fid);
126 goto free_session;
127 }
128
129 sb = sget(type: fs_type, NULL, set: v9fs_set_super, flags, data: v9ses);
130 if (IS_ERR(ptr: sb)) {
131 retval = PTR_ERR(ptr: 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, rdev: 0);
144 if (IS_ERR(ptr: inode)) {
145 retval = PTR_ERR(ptr: 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(ptr: st)) {
160 retval = PTR_ERR(ptr: st);
161 goto release_sb;
162 }
163 d_inode(dentry: root)->i_ino = v9fs_qid2ino(qid: &st->qid);
164 v9fs_stat2inode_dotl(stat: st, inode: d_inode(dentry: root), flags: 0);
165 kfree(objp: st);
166 } else {
167 struct p9_wstat *st = NULL;
168
169 st = p9_client_stat(fid);
170 if (IS_ERR(ptr: st)) {
171 retval = PTR_ERR(ptr: st);
172 goto release_sb;
173 }
174
175 d_inode(dentry: root)->i_ino = v9fs_qid2ino(qid: &st->qid);
176 v9fs_stat2inode(stat: st, inode: d_inode(dentry: root), sb, flags: 0);
177
178 p9stat_free(stbuf: st);
179 kfree(objp: st);
180 }
181 retval = v9fs_get_acl(inode, fid);
182 if (retval)
183 goto release_sb;
184 v9fs_fid_add(dentry: root, fid: &fid);
185
186 p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
187 return dget(dentry: sb->s_root);
188
189clunk_fid:
190 p9_fid_put(fid);
191 v9fs_session_close(v9ses);
192free_session:
193 kfree(objp: v9ses);
194 return ERR_PTR(error: 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(error: 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(sb: s);
221
222 v9fs_session_cancel(v9ses);
223 v9fs_session_close(v9ses);
224 kfree(objp: 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(ptr: fid)) {
247 res = PTR_ERR(ptr: fid);
248 goto done;
249 }
250
251 v9ses = v9fs_dentry2v9ses(dentry);
252 if (v9fs_proto_dotl(v9ses)) {
253 res = p9_client_statfs(fid, sb: &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(v: 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, cookie: 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, cookie: 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

source code of linux/fs/9p/vfs_super.c