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
31 static 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
40 static 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
54 static int
55 v9fs_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
106 static 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
162 clunk_fid:
163 p9_fid_put(fid);
164 v9fs_session_close(v9ses);
165 free_session:
166 kfree(v9ses);
167 return ERR_PTR(retval);
168
169 release_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
187 static 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
202 static void
203 v9fs_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
211 static 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);
242 done:
243 p9_fid_put(fid);
244 return res;
245 }
246
247 static 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
262 static 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
273 static 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
282 static 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
293 static 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
304 struct 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 };
311 MODULE_ALIAS_FS("9p");
312
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