2d9ee073d12c3ab5c62062e790e2e821d5eeab7f
[releases.git] / vfs_super.c
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
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
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
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
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
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
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
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
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
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");