ALSA: mips: Convert to the common vmalloc memalloc
[sfrench/cifs-2.6.git] / arch / s390 / hypfs / inode.c
1 // SPDX-License-Identifier: GPL-1.0+
2 /*
3  *    Hypervisor filesystem for Linux on s390.
4  *
5  *    Copyright IBM Corp. 2006, 2008
6  *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
7  */
8
9 #define KMSG_COMPONENT "hypfs"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12 #include <linux/types.h>
13 #include <linux/errno.h>
14 #include <linux/fs.h>
15 #include <linux/fs_context.h>
16 #include <linux/fs_parser.h>
17 #include <linux/namei.h>
18 #include <linux/vfs.h>
19 #include <linux/slab.h>
20 #include <linux/pagemap.h>
21 #include <linux/time.h>
22 #include <linux/sysfs.h>
23 #include <linux/init.h>
24 #include <linux/kobject.h>
25 #include <linux/seq_file.h>
26 #include <linux/uio.h>
27 #include <asm/ebcdic.h>
28 #include "hypfs.h"
29
30 #define HYPFS_MAGIC 0x687970    /* ASCII 'hyp' */
31 #define TMP_SIZE 64             /* size of temporary buffers */
32
33 static struct dentry *hypfs_create_update_file(struct dentry *dir);
34
35 struct hypfs_sb_info {
36         kuid_t uid;                     /* uid used for files and dirs */
37         kgid_t gid;                     /* gid used for files and dirs */
38         struct dentry *update_file;     /* file to trigger update */
39         time64_t last_update;           /* last update, CLOCK_MONOTONIC time */
40         struct mutex lock;              /* lock to protect update process */
41 };
42
43 static const struct file_operations hypfs_file_ops;
44 static struct file_system_type hypfs_type;
45 static const struct super_operations hypfs_s_ops;
46
47 /* start of list of all dentries, which have to be deleted on update */
48 static struct dentry *hypfs_last_dentry;
49
50 static void hypfs_update_update(struct super_block *sb)
51 {
52         struct hypfs_sb_info *sb_info = sb->s_fs_info;
53         struct inode *inode = d_inode(sb_info->update_file);
54
55         sb_info->last_update = ktime_get_seconds();
56         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
57 }
58
59 /* directory tree removal functions */
60
61 static void hypfs_add_dentry(struct dentry *dentry)
62 {
63         dentry->d_fsdata = hypfs_last_dentry;
64         hypfs_last_dentry = dentry;
65 }
66
67 static void hypfs_remove(struct dentry *dentry)
68 {
69         struct dentry *parent;
70
71         parent = dentry->d_parent;
72         inode_lock(d_inode(parent));
73         if (simple_positive(dentry)) {
74                 if (d_is_dir(dentry))
75                         simple_rmdir(d_inode(parent), dentry);
76                 else
77                         simple_unlink(d_inode(parent), dentry);
78         }
79         d_drop(dentry);
80         dput(dentry);
81         inode_unlock(d_inode(parent));
82 }
83
84 static void hypfs_delete_tree(struct dentry *root)
85 {
86         while (hypfs_last_dentry) {
87                 struct dentry *next_dentry;
88                 next_dentry = hypfs_last_dentry->d_fsdata;
89                 hypfs_remove(hypfs_last_dentry);
90                 hypfs_last_dentry = next_dentry;
91         }
92 }
93
94 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
95 {
96         struct inode *ret = new_inode(sb);
97
98         if (ret) {
99                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
100                 ret->i_ino = get_next_ino();
101                 ret->i_mode = mode;
102                 ret->i_uid = hypfs_info->uid;
103                 ret->i_gid = hypfs_info->gid;
104                 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
105                 if (S_ISDIR(mode))
106                         set_nlink(ret, 2);
107         }
108         return ret;
109 }
110
111 static void hypfs_evict_inode(struct inode *inode)
112 {
113         clear_inode(inode);
114         kfree(inode->i_private);
115 }
116
117 static int hypfs_open(struct inode *inode, struct file *filp)
118 {
119         char *data = file_inode(filp)->i_private;
120         struct hypfs_sb_info *fs_info;
121
122         if (filp->f_mode & FMODE_WRITE) {
123                 if (!(inode->i_mode & S_IWUGO))
124                         return -EACCES;
125         }
126         if (filp->f_mode & FMODE_READ) {
127                 if (!(inode->i_mode & S_IRUGO))
128                         return -EACCES;
129         }
130
131         fs_info = inode->i_sb->s_fs_info;
132         if(data) {
133                 mutex_lock(&fs_info->lock);
134                 filp->private_data = kstrdup(data, GFP_KERNEL);
135                 if (!filp->private_data) {
136                         mutex_unlock(&fs_info->lock);
137                         return -ENOMEM;
138                 }
139                 mutex_unlock(&fs_info->lock);
140         }
141         return nonseekable_open(inode, filp);
142 }
143
144 static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
145 {
146         struct file *file = iocb->ki_filp;
147         char *data = file->private_data;
148         size_t available = strlen(data);
149         loff_t pos = iocb->ki_pos;
150         size_t count;
151
152         if (pos < 0)
153                 return -EINVAL;
154         if (pos >= available || !iov_iter_count(to))
155                 return 0;
156         count = copy_to_iter(data + pos, available - pos, to);
157         if (!count)
158                 return -EFAULT;
159         iocb->ki_pos = pos + count;
160         file_accessed(file);
161         return count;
162 }
163
164 static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
165 {
166         int rc;
167         struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
168         struct hypfs_sb_info *fs_info = sb->s_fs_info;
169         size_t count = iov_iter_count(from);
170
171         /*
172          * Currently we only allow one update per second for two reasons:
173          * 1. diag 204 is VERY expensive
174          * 2. If several processes do updates in parallel and then read the
175          *    hypfs data, the likelihood of collisions is reduced, if we restrict
176          *    the minimum update interval. A collision occurs, if during the
177          *    data gathering of one process another process triggers an update
178          *    If the first process wants to ensure consistent data, it has
179          *    to restart data collection in this case.
180          */
181         mutex_lock(&fs_info->lock);
182         if (fs_info->last_update == ktime_get_seconds()) {
183                 rc = -EBUSY;
184                 goto out;
185         }
186         hypfs_delete_tree(sb->s_root);
187         if (MACHINE_IS_VM)
188                 rc = hypfs_vm_create_files(sb->s_root);
189         else
190                 rc = hypfs_diag_create_files(sb->s_root);
191         if (rc) {
192                 pr_err("Updating the hypfs tree failed\n");
193                 hypfs_delete_tree(sb->s_root);
194                 goto out;
195         }
196         hypfs_update_update(sb);
197         rc = count;
198         iov_iter_advance(from, count);
199 out:
200         mutex_unlock(&fs_info->lock);
201         return rc;
202 }
203
204 static int hypfs_release(struct inode *inode, struct file *filp)
205 {
206         kfree(filp->private_data);
207         return 0;
208 }
209
210 enum { Opt_uid, Opt_gid, };
211
212 static const struct fs_parameter_spec hypfs_param_specs[] = {
213         fsparam_u32("gid", Opt_gid),
214         fsparam_u32("uid", Opt_uid),
215         {}
216 };
217
218 static const struct fs_parameter_description hypfs_fs_parameters = {
219         .name           = "hypfs",
220         .specs          = hypfs_param_specs,
221 };
222
223 static int hypfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
224 {
225         struct hypfs_sb_info *hypfs_info = fc->s_fs_info;
226         struct fs_parse_result result;
227         kuid_t uid;
228         kgid_t gid;
229         int opt;
230
231         opt = fs_parse(fc, &hypfs_fs_parameters, param, &result);
232         if (opt < 0)
233                 return opt;
234
235         switch (opt) {
236         case Opt_uid:
237                 uid = make_kuid(current_user_ns(), result.uint_32);
238                 if (!uid_valid(uid))
239                         return invalf(fc, "Unknown uid");
240                 hypfs_info->uid = uid;
241                 break;
242         case Opt_gid:
243                 gid = make_kgid(current_user_ns(), result.uint_32);
244                 if (!gid_valid(gid))
245                         return invalf(fc, "Unknown gid");
246                 hypfs_info->gid = gid;
247                 break;
248         }
249         return 0;
250 }
251
252 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
253 {
254         struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
255
256         seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
257         seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
258         return 0;
259 }
260
261 static int hypfs_fill_super(struct super_block *sb, struct fs_context *fc)
262 {
263         struct hypfs_sb_info *sbi = sb->s_fs_info;
264         struct inode *root_inode;
265         struct dentry *root_dentry, *update_file;
266         int rc;
267
268         sb->s_blocksize = PAGE_SIZE;
269         sb->s_blocksize_bits = PAGE_SHIFT;
270         sb->s_magic = HYPFS_MAGIC;
271         sb->s_op = &hypfs_s_ops;
272
273         root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
274         if (!root_inode)
275                 return -ENOMEM;
276         root_inode->i_op = &simple_dir_inode_operations;
277         root_inode->i_fop = &simple_dir_operations;
278         sb->s_root = root_dentry = d_make_root(root_inode);
279         if (!root_dentry)
280                 return -ENOMEM;
281         if (MACHINE_IS_VM)
282                 rc = hypfs_vm_create_files(root_dentry);
283         else
284                 rc = hypfs_diag_create_files(root_dentry);
285         if (rc)
286                 return rc;
287         update_file = hypfs_create_update_file(root_dentry);
288         if (IS_ERR(update_file))
289                 return PTR_ERR(update_file);
290         sbi->update_file = update_file;
291         hypfs_update_update(sb);
292         pr_info("Hypervisor filesystem mounted\n");
293         return 0;
294 }
295
296 static int hypfs_get_tree(struct fs_context *fc)
297 {
298         return get_tree_single(fc, hypfs_fill_super);
299 }
300
301 static void hypfs_free_fc(struct fs_context *fc)
302 {
303         kfree(fc->s_fs_info);
304 }
305
306 static const struct fs_context_operations hypfs_context_ops = {
307         .free           = hypfs_free_fc,
308         .parse_param    = hypfs_parse_param,
309         .get_tree       = hypfs_get_tree,
310 };
311
312 static int hypfs_init_fs_context(struct fs_context *fc)
313 {
314         struct hypfs_sb_info *sbi;
315
316         sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
317         if (!sbi)
318                 return -ENOMEM;
319
320         mutex_init(&sbi->lock);
321         sbi->uid = current_uid();
322         sbi->gid = current_gid();
323
324         fc->s_fs_info = sbi;
325         fc->ops = &hypfs_context_ops;
326         return 0;
327 }
328
329 static void hypfs_kill_super(struct super_block *sb)
330 {
331         struct hypfs_sb_info *sb_info = sb->s_fs_info;
332
333         if (sb->s_root)
334                 hypfs_delete_tree(sb->s_root);
335         if (sb_info && sb_info->update_file)
336                 hypfs_remove(sb_info->update_file);
337         kfree(sb->s_fs_info);
338         sb->s_fs_info = NULL;
339         kill_litter_super(sb);
340 }
341
342 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name,
343                                         char *data, umode_t mode)
344 {
345         struct dentry *dentry;
346         struct inode *inode;
347
348         inode_lock(d_inode(parent));
349         dentry = lookup_one_len(name, parent, strlen(name));
350         if (IS_ERR(dentry)) {
351                 dentry = ERR_PTR(-ENOMEM);
352                 goto fail;
353         }
354         inode = hypfs_make_inode(parent->d_sb, mode);
355         if (!inode) {
356                 dput(dentry);
357                 dentry = ERR_PTR(-ENOMEM);
358                 goto fail;
359         }
360         if (S_ISREG(mode)) {
361                 inode->i_fop = &hypfs_file_ops;
362                 if (data)
363                         inode->i_size = strlen(data);
364                 else
365                         inode->i_size = 0;
366         } else if (S_ISDIR(mode)) {
367                 inode->i_op = &simple_dir_inode_operations;
368                 inode->i_fop = &simple_dir_operations;
369                 inc_nlink(d_inode(parent));
370         } else
371                 BUG();
372         inode->i_private = data;
373         d_instantiate(dentry, inode);
374         dget(dentry);
375 fail:
376         inode_unlock(d_inode(parent));
377         return dentry;
378 }
379
380 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name)
381 {
382         struct dentry *dentry;
383
384         dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE);
385         if (IS_ERR(dentry))
386                 return dentry;
387         hypfs_add_dentry(dentry);
388         return dentry;
389 }
390
391 static struct dentry *hypfs_create_update_file(struct dentry *dir)
392 {
393         struct dentry *dentry;
394
395         dentry = hypfs_create_file(dir, "update", NULL,
396                                    S_IFREG | UPDATE_FILE_MODE);
397         /*
398          * We do not put the update file on the 'delete' list with
399          * hypfs_add_dentry(), since it should not be removed when the tree
400          * is updated.
401          */
402         return dentry;
403 }
404
405 struct dentry *hypfs_create_u64(struct dentry *dir,
406                                 const char *name, __u64 value)
407 {
408         char *buffer;
409         char tmp[TMP_SIZE];
410         struct dentry *dentry;
411
412         snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
413         buffer = kstrdup(tmp, GFP_KERNEL);
414         if (!buffer)
415                 return ERR_PTR(-ENOMEM);
416         dentry =
417             hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
418         if (IS_ERR(dentry)) {
419                 kfree(buffer);
420                 return ERR_PTR(-ENOMEM);
421         }
422         hypfs_add_dentry(dentry);
423         return dentry;
424 }
425
426 struct dentry *hypfs_create_str(struct dentry *dir,
427                                 const char *name, char *string)
428 {
429         char *buffer;
430         struct dentry *dentry;
431
432         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
433         if (!buffer)
434                 return ERR_PTR(-ENOMEM);
435         sprintf(buffer, "%s\n", string);
436         dentry =
437             hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
438         if (IS_ERR(dentry)) {
439                 kfree(buffer);
440                 return ERR_PTR(-ENOMEM);
441         }
442         hypfs_add_dentry(dentry);
443         return dentry;
444 }
445
446 static const struct file_operations hypfs_file_ops = {
447         .open           = hypfs_open,
448         .release        = hypfs_release,
449         .read_iter      = hypfs_read_iter,
450         .write_iter     = hypfs_write_iter,
451         .llseek         = no_llseek,
452 };
453
454 static struct file_system_type hypfs_type = {
455         .owner          = THIS_MODULE,
456         .name           = "s390_hypfs",
457         .init_fs_context = hypfs_init_fs_context,
458         .parameters     = &hypfs_fs_parameters,
459         .kill_sb        = hypfs_kill_super
460 };
461
462 static const struct super_operations hypfs_s_ops = {
463         .statfs         = simple_statfs,
464         .evict_inode    = hypfs_evict_inode,
465         .show_options   = hypfs_show_options,
466 };
467
468 static int __init hypfs_init(void)
469 {
470         int rc;
471
472         hypfs_dbfs_init();
473
474         if (hypfs_diag_init()) {
475                 rc = -ENODATA;
476                 goto fail_dbfs_exit;
477         }
478         if (hypfs_vm_init()) {
479                 rc = -ENODATA;
480                 goto fail_hypfs_diag_exit;
481         }
482         hypfs_sprp_init();
483         if (hypfs_diag0c_init()) {
484                 rc = -ENODATA;
485                 goto fail_hypfs_sprp_exit;
486         }
487         rc = sysfs_create_mount_point(hypervisor_kobj, "s390");
488         if (rc)
489                 goto fail_hypfs_diag0c_exit;
490         rc = register_filesystem(&hypfs_type);
491         if (rc)
492                 goto fail_filesystem;
493         return 0;
494
495 fail_filesystem:
496         sysfs_remove_mount_point(hypervisor_kobj, "s390");
497 fail_hypfs_diag0c_exit:
498         hypfs_diag0c_exit();
499 fail_hypfs_sprp_exit:
500         hypfs_sprp_exit();
501         hypfs_vm_exit();
502 fail_hypfs_diag_exit:
503         hypfs_diag_exit();
504 fail_dbfs_exit:
505         hypfs_dbfs_exit();
506         pr_err("Initialization of hypfs failed with rc=%i\n", rc);
507         return rc;
508 }
509 device_initcall(hypfs_init)