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/inet.h>
16 #include <linux/pagemap.h>
17 #include <linux/mount.h>
18 #include <linux/idr.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/statfs.h>
22 #include <linux/magic.h>
23 #include <linux/fscache.h>
24 #include <net/9p/9p.h>
25 #include <net/9p/client.h>
26 
27 #include "v9fs.h"
28 #include "v9fs_vfs.h"
29 #include "fid.h"
30 #include "xattr.h"
31 #include "acl.h"
32 
33 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
34 
35 /**
36  * v9fs_set_super - set the superblock
37  * @s: super block
38  * @data: file system specific data
39  *
40  */
41 
v9fs_set_super(struct super_block * s,void * data)42 static int v9fs_set_super(struct super_block *s, void *data)
43 {
44 	s->s_fs_info = data;
45 	return set_anon_super(s, data);
46 }
47 
48 /**
49  * v9fs_fill_super - populate superblock with info
50  * @sb: superblock
51  * @v9ses: session information
52  * @flags: flags propagated from v9fs_mount()
53  *
54  */
55 
56 static int
v9fs_fill_super(struct super_block * sb,struct v9fs_session_info * v9ses,int flags)57 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
58 		int flags)
59 {
60 	int ret;
61 
62 	sb->s_maxbytes = MAX_LFS_FILESIZE;
63 	sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
64 	sb->s_blocksize = 1 << sb->s_blocksize_bits;
65 	sb->s_magic = V9FS_MAGIC;
66 	if (v9fs_proto_dotl(v9ses)) {
67 		sb->s_op = &v9fs_super_ops_dotl;
68 		sb->s_xattr = v9fs_xattr_handlers;
69 	} else {
70 		sb->s_op = &v9fs_super_ops;
71 		sb->s_time_max = U32_MAX;
72 	}
73 
74 	sb->s_time_min = 0;
75 
76 	ret = super_setup_bdi(sb);
77 	if (ret)
78 		return ret;
79 
80 	if (!v9ses->cache) {
81 		sb->s_bdi->ra_pages = 0;
82 		sb->s_bdi->io_pages = 0;
83 	} else {
84 		sb->s_bdi->ra_pages = v9ses->maxdata >> PAGE_SHIFT;
85 		sb->s_bdi->io_pages = v9ses->maxdata >> PAGE_SHIFT;
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 = 0777 | 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 
161 		st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
162 		if (IS_ERR(st)) {
163 			retval = PTR_ERR(st);
164 			goto release_sb;
165 		}
166 		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
167 		v9fs_stat2inode_dotl(st, d_inode(root), 0);
168 		kfree(st);
169 	} else {
170 		struct p9_wstat *st = NULL;
171 
172 		st = p9_client_stat(fid);
173 		if (IS_ERR(st)) {
174 			retval = PTR_ERR(st);
175 			goto release_sb;
176 		}
177 
178 		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
179 		v9fs_stat2inode(st, d_inode(root), sb, 0);
180 
181 		p9stat_free(st);
182 		kfree(st);
183 	}
184 	retval = v9fs_get_acl(inode, fid);
185 	if (retval)
186 		goto release_sb;
187 	v9fs_fid_add(root, &fid);
188 
189 	p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
190 	return dget(sb->s_root);
191 
192 clunk_fid:
193 	p9_fid_put(fid);
194 	v9fs_session_close(v9ses);
195 free_session:
196 	kfree(v9ses);
197 	return ERR_PTR(retval);
198 
199 release_sb:
200 	/*
201 	 * we will do the session_close and root dentry release
202 	 * in the below call. But we need to clunk fid, because we haven't
203 	 * attached the fid to dentry so it won't get clunked
204 	 * automatically.
205 	 */
206 	p9_fid_put(fid);
207 	deactivate_locked_super(sb);
208 	return ERR_PTR(retval);
209 }
210 
211 /**
212  * v9fs_kill_super - Kill Superblock
213  * @s: superblock
214  *
215  */
216 
v9fs_kill_super(struct super_block * s)217 static void v9fs_kill_super(struct super_block *s)
218 {
219 	struct v9fs_session_info *v9ses = s->s_fs_info;
220 
221 	p9_debug(P9_DEBUG_VFS, " %p\n", s);
222 
223 	kill_anon_super(s);
224 
225 	v9fs_session_cancel(v9ses);
226 	v9fs_session_close(v9ses);
227 	kfree(v9ses);
228 	s->s_fs_info = NULL;
229 	p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
230 }
231 
232 static void
v9fs_umount_begin(struct super_block * sb)233 v9fs_umount_begin(struct super_block *sb)
234 {
235 	struct v9fs_session_info *v9ses;
236 
237 	v9ses = sb->s_fs_info;
238 	v9fs_session_begin_cancel(v9ses);
239 }
240 
v9fs_statfs(struct dentry * dentry,struct kstatfs * buf)241 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
242 {
243 	struct v9fs_session_info *v9ses;
244 	struct p9_fid *fid;
245 	struct p9_rstatfs rs;
246 	int res;
247 
248 	fid = v9fs_fid_lookup(dentry);
249 	if (IS_ERR(fid)) {
250 		res = PTR_ERR(fid);
251 		goto done;
252 	}
253 
254 	v9ses = v9fs_dentry2v9ses(dentry);
255 	if (v9fs_proto_dotl(v9ses)) {
256 		res = p9_client_statfs(fid, &rs);
257 		if (res == 0) {
258 			buf->f_type = rs.type;
259 			buf->f_bsize = rs.bsize;
260 			buf->f_blocks = rs.blocks;
261 			buf->f_bfree = rs.bfree;
262 			buf->f_bavail = rs.bavail;
263 			buf->f_files = rs.files;
264 			buf->f_ffree = rs.ffree;
265 			buf->f_fsid = u64_to_fsid(rs.fsid);
266 			buf->f_namelen = rs.namelen;
267 		}
268 		if (res != -ENOSYS)
269 			goto done;
270 	}
271 	res = simple_statfs(dentry, buf);
272 done:
273 	p9_fid_put(fid);
274 	return res;
275 }
276 
v9fs_drop_inode(struct inode * inode)277 static int v9fs_drop_inode(struct inode *inode)
278 {
279 	struct v9fs_session_info *v9ses;
280 
281 	v9ses = v9fs_inode2v9ses(inode);
282 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
283 		return generic_drop_inode(inode);
284 	/*
285 	 * in case of non cached mode always drop the
286 	 * inode because we want the inode attribute
287 	 * to always match that on the server.
288 	 */
289 	return 1;
290 }
291 
v9fs_write_inode(struct inode * inode,struct writeback_control * wbc)292 static int v9fs_write_inode(struct inode *inode,
293 			    struct writeback_control *wbc)
294 {
295 	int ret;
296 	struct p9_wstat wstat;
297 	struct v9fs_inode *v9inode;
298 	/*
299 	 * send an fsync request to server irrespective of
300 	 * wbc->sync_mode.
301 	 */
302 	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
303 	v9inode = V9FS_I(inode);
304 	if (!v9inode->writeback_fid)
305 		return 0;
306 	v9fs_blank_wstat(&wstat);
307 
308 	ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
309 	if (ret < 0) {
310 		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
311 		return ret;
312 	}
313 	fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
314 	return 0;
315 }
316 
v9fs_write_inode_dotl(struct inode * inode,struct writeback_control * wbc)317 static int v9fs_write_inode_dotl(struct inode *inode,
318 				 struct writeback_control *wbc)
319 {
320 	int ret;
321 	struct v9fs_inode *v9inode;
322 	/*
323 	 * send an fsync request to server irrespective of
324 	 * wbc->sync_mode.
325 	 */
326 	v9inode = V9FS_I(inode);
327 	p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
328 		 __func__, inode, v9inode->writeback_fid);
329 	if (!v9inode->writeback_fid)
330 		return 0;
331 
332 	ret = p9_client_fsync(v9inode->writeback_fid, 0);
333 	if (ret < 0) {
334 		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
335 		return ret;
336 	}
337 	fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
338 	return 0;
339 }
340 
341 static const struct super_operations v9fs_super_ops = {
342 	.alloc_inode = v9fs_alloc_inode,
343 	.free_inode = v9fs_free_inode,
344 	.statfs = simple_statfs,
345 	.evict_inode = v9fs_evict_inode,
346 	.show_options = v9fs_show_options,
347 	.umount_begin = v9fs_umount_begin,
348 	.write_inode = v9fs_write_inode,
349 };
350 
351 static const struct super_operations v9fs_super_ops_dotl = {
352 	.alloc_inode = v9fs_alloc_inode,
353 	.free_inode = v9fs_free_inode,
354 	.statfs = v9fs_statfs,
355 	.drop_inode = v9fs_drop_inode,
356 	.evict_inode = v9fs_evict_inode,
357 	.show_options = v9fs_show_options,
358 	.umount_begin = v9fs_umount_begin,
359 	.write_inode = v9fs_write_inode_dotl,
360 };
361 
362 struct file_system_type v9fs_fs_type = {
363 	.name = "9p",
364 	.mount = v9fs_mount,
365 	.kill_sb = v9fs_kill_super,
366 	.owner = THIS_MODULE,
367 	.fs_flags = FS_RENAME_DOES_D_MOVE,
368 };
369 MODULE_ALIAS_FS("9p");
370