2 * arch/s390/hypfs/inode.c
3 * Hypervisor filesystem for Linux on s390.
5 * Copyright (C) IBM Corp. 2006
6 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
9 #include <linux/types.h>
10 #include <linux/errno.h>
12 #include <linux/namei.h>
13 #include <linux/vfs.h>
14 #include <linux/pagemap.h>
15 #include <linux/gfp.h>
16 #include <linux/time.h>
17 #include <linux/parser.h>
18 #include <linux/sysfs.h>
19 #include <linux/module.h>
20 #include <asm/ebcdic.h>
22 #include "hypfs_diag.h"
24 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
25 #define TMP_SIZE 64 /* size of temporary buffers */
27 static struct dentry
*hypfs_create_update_file(struct super_block
*sb
,
30 struct hypfs_sb_info
{
31 uid_t uid
; /* uid used for files and dirs */
32 gid_t gid
; /* gid used for files and dirs */
33 struct dentry
*update_file
; /* file to trigger update */
34 time_t last_update
; /* last update time in secs since 1970 */
35 struct mutex lock
; /* lock to protect update process */
38 static struct file_operations hypfs_file_ops
;
39 static struct file_system_type hypfs_type
;
40 static struct super_operations hypfs_s_ops
;
42 /* start of list of all dentries, which have to be deleted on update */
43 static struct dentry
*hypfs_last_dentry
;
45 static void hypfs_update_update(struct super_block
*sb
)
47 struct hypfs_sb_info
*sb_info
= sb
->s_fs_info
;
48 struct inode
*inode
= sb_info
->update_file
->d_inode
;
50 sb_info
->last_update
= get_seconds();
51 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= CURRENT_TIME
;
54 /* directory tree removal functions */
56 static void hypfs_add_dentry(struct dentry
*dentry
)
58 dentry
->d_fsdata
= hypfs_last_dentry
;
59 hypfs_last_dentry
= dentry
;
62 static void hypfs_remove(struct dentry
*dentry
)
64 struct dentry
*parent
;
66 parent
= dentry
->d_parent
;
67 if (S_ISDIR(dentry
->d_inode
->i_mode
))
68 simple_rmdir(parent
->d_inode
, dentry
);
70 simple_unlink(parent
->d_inode
, dentry
);
75 static void hypfs_delete_tree(struct dentry
*root
)
77 while (hypfs_last_dentry
) {
78 struct dentry
*next_dentry
;
79 next_dentry
= hypfs_last_dentry
->d_fsdata
;
80 hypfs_remove(hypfs_last_dentry
);
81 hypfs_last_dentry
= next_dentry
;
85 static struct inode
*hypfs_make_inode(struct super_block
*sb
, int mode
)
87 struct inode
*ret
= new_inode(sb
);
90 struct hypfs_sb_info
*hypfs_info
= sb
->s_fs_info
;
92 ret
->i_uid
= hypfs_info
->uid
;
93 ret
->i_gid
= hypfs_info
->gid
;
95 ret
->i_atime
= ret
->i_mtime
= ret
->i_ctime
= CURRENT_TIME
;
104 static void hypfs_drop_inode(struct inode
*inode
)
106 kfree(inode
->i_private
);
107 generic_delete_inode(inode
);
110 static int hypfs_open(struct inode
*inode
, struct file
*filp
)
112 char *data
= filp
->f_path
.dentry
->d_inode
->i_private
;
113 struct hypfs_sb_info
*fs_info
;
115 if (filp
->f_mode
& FMODE_WRITE
) {
116 if (!(inode
->i_mode
& S_IWUGO
))
119 if (filp
->f_mode
& FMODE_READ
) {
120 if (!(inode
->i_mode
& S_IRUGO
))
124 fs_info
= inode
->i_sb
->s_fs_info
;
126 mutex_lock(&fs_info
->lock
);
127 filp
->private_data
= kstrdup(data
, GFP_KERNEL
);
128 if (!filp
->private_data
) {
129 mutex_unlock(&fs_info
->lock
);
132 mutex_unlock(&fs_info
->lock
);
137 static ssize_t
hypfs_aio_read(struct kiocb
*iocb
, const struct iovec
*iov
,
138 unsigned long nr_segs
, loff_t offset
)
142 struct file
*filp
= iocb
->ki_filp
;
144 char __user
*buf
= iov
[0].iov_base
;
145 size_t count
= iov
[0].iov_len
;
152 data
= filp
->private_data
;
158 if (count
> len
- offset
)
159 count
= len
- offset
;
160 if (copy_to_user(buf
, data
+ offset
, count
)) {
164 iocb
->ki_pos
+= count
;
169 static ssize_t
hypfs_aio_write(struct kiocb
*iocb
, const struct iovec
*iov
,
170 unsigned long nr_segs
, loff_t offset
)
173 struct super_block
*sb
;
174 struct hypfs_sb_info
*fs_info
;
175 size_t count
= iov_length(iov
, nr_segs
);
177 sb
= iocb
->ki_filp
->f_path
.dentry
->d_inode
->i_sb
;
178 fs_info
= sb
->s_fs_info
;
180 * Currently we only allow one update per second for two reasons:
181 * 1. diag 204 is VERY expensive
182 * 2. If several processes do updates in parallel and then read the
183 * hypfs data, the likelihood of collisions is reduced, if we restrict
184 * the minimum update interval. A collision occurs, if during the
185 * data gathering of one process another process triggers an update
186 * If the first process wants to ensure consistent data, it has
187 * to restart data collection in this case.
189 mutex_lock(&fs_info
->lock
);
190 if (fs_info
->last_update
== get_seconds()) {
194 hypfs_delete_tree(sb
->s_root
);
195 rc
= hypfs_diag_create_files(sb
, sb
->s_root
);
197 printk(KERN_ERR
"hypfs: Update failed\n");
198 hypfs_delete_tree(sb
->s_root
);
201 hypfs_update_update(sb
);
204 mutex_unlock(&fs_info
->lock
);
208 static int hypfs_release(struct inode
*inode
, struct file
*filp
)
210 kfree(filp
->private_data
);
214 enum { opt_uid
, opt_gid
, opt_err
};
216 static match_table_t hypfs_tokens
= {
222 static int hypfs_parse_options(char *options
, struct super_block
*sb
)
225 substring_t args
[MAX_OPT_ARGS
];
229 while ((str
= strsep(&options
, ",")) != NULL
) {
231 struct hypfs_sb_info
*hypfs_info
= sb
->s_fs_info
;
235 token
= match_token(str
, hypfs_tokens
, args
);
238 if (match_int(&args
[0], &option
))
240 hypfs_info
->uid
= option
;
243 if (match_int(&args
[0], &option
))
245 hypfs_info
->gid
= option
;
249 printk(KERN_ERR
"hypfs: Unrecognized mount option "
250 "\"%s\" or missing value\n", str
);
257 static int hypfs_fill_super(struct super_block
*sb
, void *data
, int silent
)
259 struct inode
*root_inode
;
260 struct dentry
*root_dentry
;
262 struct hypfs_sb_info
*sbi
;
264 sbi
= kzalloc(sizeof(struct hypfs_sb_info
), GFP_KERNEL
);
267 mutex_init(&sbi
->lock
);
268 sbi
->uid
= current
->uid
;
269 sbi
->gid
= current
->gid
;
271 sb
->s_blocksize
= PAGE_CACHE_SIZE
;
272 sb
->s_blocksize_bits
= PAGE_CACHE_SHIFT
;
273 sb
->s_magic
= HYPFS_MAGIC
;
274 sb
->s_op
= &hypfs_s_ops
;
275 if (hypfs_parse_options(data
, sb
)) {
279 root_inode
= hypfs_make_inode(sb
, S_IFDIR
| 0755);
284 root_inode
->i_op
= &simple_dir_inode_operations
;
285 root_inode
->i_fop
= &simple_dir_operations
;
286 root_dentry
= d_alloc_root(root_inode
);
292 rc
= hypfs_diag_create_files(sb
, root_dentry
);
295 sbi
->update_file
= hypfs_create_update_file(sb
, root_dentry
);
296 if (IS_ERR(sbi
->update_file
)) {
297 rc
= PTR_ERR(sbi
->update_file
);
300 hypfs_update_update(sb
);
301 sb
->s_root
= root_dentry
;
305 hypfs_delete_tree(root_dentry
);
306 d_genocide(root_dentry
);
313 static int hypfs_get_super(struct file_system_type
*fst
, int flags
,
314 const char *devname
, void *data
, struct vfsmount
*mnt
)
316 return get_sb_single(fst
, flags
, data
, hypfs_fill_super
, mnt
);
319 static void hypfs_kill_super(struct super_block
*sb
)
321 struct hypfs_sb_info
*sb_info
= sb
->s_fs_info
;
324 hypfs_delete_tree(sb
->s_root
);
325 hypfs_remove(sb_info
->update_file
);
326 kfree(sb
->s_fs_info
);
327 sb
->s_fs_info
= NULL
;
329 kill_litter_super(sb
);
332 static struct dentry
*hypfs_create_file(struct super_block
*sb
,
333 struct dentry
*parent
, const char *name
,
334 char *data
, mode_t mode
)
336 struct dentry
*dentry
;
341 qname
.len
= strlen(name
);
342 qname
.hash
= full_name_hash(name
, qname
.len
);
343 dentry
= lookup_one_len(name
, parent
, strlen(name
));
345 return ERR_PTR(-ENOMEM
);
346 inode
= hypfs_make_inode(sb
, mode
);
349 return ERR_PTR(-ENOMEM
);
351 if (mode
& S_IFREG
) {
352 inode
->i_fop
= &hypfs_file_ops
;
354 inode
->i_size
= strlen(data
);
357 } else if (mode
& S_IFDIR
) {
358 inode
->i_op
= &simple_dir_inode_operations
;
359 inode
->i_fop
= &simple_dir_operations
;
360 parent
->d_inode
->i_nlink
++;
363 inode
->i_private
= data
;
364 d_instantiate(dentry
, inode
);
369 struct dentry
*hypfs_mkdir(struct super_block
*sb
, struct dentry
*parent
,
372 struct dentry
*dentry
;
374 dentry
= hypfs_create_file(sb
, parent
, name
, NULL
, S_IFDIR
| DIR_MODE
);
377 hypfs_add_dentry(dentry
);
378 parent
->d_inode
->i_nlink
++;
382 static struct dentry
*hypfs_create_update_file(struct super_block
*sb
,
385 struct dentry
*dentry
;
387 dentry
= hypfs_create_file(sb
, dir
, "update", NULL
,
388 S_IFREG
| UPDATE_FILE_MODE
);
390 * We do not put the update file on the 'delete' list with
391 * hypfs_add_dentry(), since it should not be removed when the tree
397 struct dentry
*hypfs_create_u64(struct super_block
*sb
, struct dentry
*dir
,
398 const char *name
, __u64 value
)
402 struct dentry
*dentry
;
404 snprintf(tmp
, TMP_SIZE
, "%lld\n", (unsigned long long int)value
);
405 buffer
= kstrdup(tmp
, GFP_KERNEL
);
407 return ERR_PTR(-ENOMEM
);
409 hypfs_create_file(sb
, dir
, name
, buffer
, S_IFREG
| REG_FILE_MODE
);
410 if (IS_ERR(dentry
)) {
412 return ERR_PTR(-ENOMEM
);
414 hypfs_add_dentry(dentry
);
418 struct dentry
*hypfs_create_str(struct super_block
*sb
, struct dentry
*dir
,
419 const char *name
, char *string
)
422 struct dentry
*dentry
;
424 buffer
= kmalloc(strlen(string
) + 2, GFP_KERNEL
);
426 return ERR_PTR(-ENOMEM
);
427 sprintf(buffer
, "%s\n", string
);
429 hypfs_create_file(sb
, dir
, name
, buffer
, S_IFREG
| REG_FILE_MODE
);
430 if (IS_ERR(dentry
)) {
432 return ERR_PTR(-ENOMEM
);
434 hypfs_add_dentry(dentry
);
438 static struct file_operations hypfs_file_ops
= {
440 .release
= hypfs_release
,
441 .read
= do_sync_read
,
442 .write
= do_sync_write
,
443 .aio_read
= hypfs_aio_read
,
444 .aio_write
= hypfs_aio_write
,
447 static struct file_system_type hypfs_type
= {
448 .owner
= THIS_MODULE
,
449 .name
= "s390_hypfs",
450 .get_sb
= hypfs_get_super
,
451 .kill_sb
= hypfs_kill_super
454 static struct super_operations hypfs_s_ops
= {
455 .statfs
= simple_statfs
,
456 .drop_inode
= hypfs_drop_inode
,
459 static decl_subsys(s390
, NULL
, NULL
);
461 static int __init
hypfs_init(void)
467 if (hypfs_diag_init()) {
471 kset_set_kset_s(&s390_subsys
, hypervisor_subsys
);
472 rc
= subsystem_register(&s390_subsys
);
475 rc
= register_filesystem(&hypfs_type
);
477 goto fail_filesystem
;
481 subsystem_unregister(&s390_subsys
);
485 printk(KERN_ERR
"hypfs: Initialization failed with rc = %i.\n", rc
);
489 static void __exit
hypfs_exit(void)
492 unregister_filesystem(&hypfs_type
);
493 subsystem_unregister(&s390_subsys
);
496 module_init(hypfs_init
)
497 module_exit(hypfs_exit
)
499 MODULE_LICENSE("GPL");
500 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
501 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");