2 * Hypervisor filesystem for Linux on s390.
4 * Copyright IBM Corp. 2006, 2008
5 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
8 #define KMSG_COMPONENT "hypfs"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11 #include <linux/types.h>
12 #include <linux/errno.h>
14 #include <linux/namei.h>
15 #include <linux/vfs.h>
16 #include <linux/slab.h>
17 #include <linux/pagemap.h>
18 #include <linux/time.h>
19 #include <linux/parser.h>
20 #include <linux/sysfs.h>
21 #include <linux/module.h>
22 #include <linux/seq_file.h>
23 #include <linux/mount.h>
24 #include <asm/ebcdic.h>
27 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
28 #define TMP_SIZE 64 /* size of temporary buffers */
30 static struct dentry
*hypfs_create_update_file(struct super_block
*sb
,
33 struct hypfs_sb_info
{
34 uid_t uid
; /* uid used for files and dirs */
35 gid_t gid
; /* gid used for files and dirs */
36 struct dentry
*update_file
; /* file to trigger update */
37 time_t last_update
; /* last update time in secs since 1970 */
38 struct mutex lock
; /* lock to protect update process */
41 static const struct file_operations hypfs_file_ops
;
42 static struct file_system_type hypfs_type
;
43 static const struct super_operations hypfs_s_ops
;
45 /* start of list of all dentries, which have to be deleted on update */
46 static struct dentry
*hypfs_last_dentry
;
48 static void hypfs_update_update(struct super_block
*sb
)
50 struct hypfs_sb_info
*sb_info
= sb
->s_fs_info
;
51 struct inode
*inode
= sb_info
->update_file
->d_inode
;
53 sb_info
->last_update
= get_seconds();
54 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= CURRENT_TIME
;
57 /* directory tree removal functions */
59 static void hypfs_add_dentry(struct dentry
*dentry
)
61 dentry
->d_fsdata
= hypfs_last_dentry
;
62 hypfs_last_dentry
= dentry
;
65 static inline int hypfs_positive(struct dentry
*dentry
)
67 return dentry
->d_inode
&& !d_unhashed(dentry
);
70 static void hypfs_remove(struct dentry
*dentry
)
72 struct dentry
*parent
;
74 parent
= dentry
->d_parent
;
75 if (!parent
|| !parent
->d_inode
)
77 mutex_lock(&parent
->d_inode
->i_mutex
);
78 if (hypfs_positive(dentry
)) {
79 if (S_ISDIR(dentry
->d_inode
->i_mode
))
80 simple_rmdir(parent
->d_inode
, dentry
);
82 simple_unlink(parent
->d_inode
, dentry
);
86 mutex_unlock(&parent
->d_inode
->i_mutex
);
89 static void hypfs_delete_tree(struct dentry
*root
)
91 while (hypfs_last_dentry
) {
92 struct dentry
*next_dentry
;
93 next_dentry
= hypfs_last_dentry
->d_fsdata
;
94 hypfs_remove(hypfs_last_dentry
);
95 hypfs_last_dentry
= next_dentry
;
99 static struct inode
*hypfs_make_inode(struct super_block
*sb
, umode_t mode
)
101 struct inode
*ret
= new_inode(sb
);
104 struct hypfs_sb_info
*hypfs_info
= sb
->s_fs_info
;
105 ret
->i_ino
= get_next_ino();
107 ret
->i_uid
= hypfs_info
->uid
;
108 ret
->i_gid
= hypfs_info
->gid
;
109 ret
->i_atime
= ret
->i_mtime
= ret
->i_ctime
= CURRENT_TIME
;
116 static void hypfs_evict_inode(struct inode
*inode
)
119 kfree(inode
->i_private
);
122 static int hypfs_open(struct inode
*inode
, struct file
*filp
)
124 char *data
= filp
->f_path
.dentry
->d_inode
->i_private
;
125 struct hypfs_sb_info
*fs_info
;
127 if (filp
->f_mode
& FMODE_WRITE
) {
128 if (!(inode
->i_mode
& S_IWUGO
))
131 if (filp
->f_mode
& FMODE_READ
) {
132 if (!(inode
->i_mode
& S_IRUGO
))
136 fs_info
= inode
->i_sb
->s_fs_info
;
138 mutex_lock(&fs_info
->lock
);
139 filp
->private_data
= kstrdup(data
, GFP_KERNEL
);
140 if (!filp
->private_data
) {
141 mutex_unlock(&fs_info
->lock
);
144 mutex_unlock(&fs_info
->lock
);
146 return nonseekable_open(inode
, filp
);
149 static ssize_t
hypfs_aio_read(struct kiocb
*iocb
, const struct iovec
*iov
,
150 unsigned long nr_segs
, loff_t offset
)
154 struct file
*filp
= iocb
->ki_filp
;
156 char __user
*buf
= iov
[0].iov_base
;
157 size_t count
= iov
[0].iov_len
;
162 data
= filp
->private_data
;
163 ret
= simple_read_from_buffer(buf
, count
, &offset
, data
, strlen(data
));
172 static ssize_t
hypfs_aio_write(struct kiocb
*iocb
, const struct iovec
*iov
,
173 unsigned long nr_segs
, loff_t offset
)
176 struct super_block
*sb
;
177 struct hypfs_sb_info
*fs_info
;
178 size_t count
= iov_length(iov
, nr_segs
);
180 sb
= iocb
->ki_filp
->f_path
.dentry
->d_inode
->i_sb
;
181 fs_info
= sb
->s_fs_info
;
183 * Currently we only allow one update per second for two reasons:
184 * 1. diag 204 is VERY expensive
185 * 2. If several processes do updates in parallel and then read the
186 * hypfs data, the likelihood of collisions is reduced, if we restrict
187 * the minimum update interval. A collision occurs, if during the
188 * data gathering of one process another process triggers an update
189 * If the first process wants to ensure consistent data, it has
190 * to restart data collection in this case.
192 mutex_lock(&fs_info
->lock
);
193 if (fs_info
->last_update
== get_seconds()) {
197 hypfs_delete_tree(sb
->s_root
);
199 rc
= hypfs_vm_create_files(sb
, sb
->s_root
);
201 rc
= hypfs_diag_create_files(sb
, sb
->s_root
);
203 pr_err("Updating the hypfs tree failed\n");
204 hypfs_delete_tree(sb
->s_root
);
207 hypfs_update_update(sb
);
210 mutex_unlock(&fs_info
->lock
);
214 static int hypfs_release(struct inode
*inode
, struct file
*filp
)
216 kfree(filp
->private_data
);
220 enum { opt_uid
, opt_gid
, opt_err
};
222 static const match_table_t hypfs_tokens
= {
228 static int hypfs_parse_options(char *options
, struct super_block
*sb
)
231 substring_t args
[MAX_OPT_ARGS
];
235 while ((str
= strsep(&options
, ",")) != NULL
) {
237 struct hypfs_sb_info
*hypfs_info
= sb
->s_fs_info
;
241 token
= match_token(str
, hypfs_tokens
, args
);
244 if (match_int(&args
[0], &option
))
246 hypfs_info
->uid
= option
;
249 if (match_int(&args
[0], &option
))
251 hypfs_info
->gid
= option
;
255 pr_err("%s is not a valid mount option\n", str
);
262 static int hypfs_show_options(struct seq_file
*s
, struct dentry
*root
)
264 struct hypfs_sb_info
*hypfs_info
= root
->d_sb
->s_fs_info
;
266 seq_printf(s
, ",uid=%u", hypfs_info
->uid
);
267 seq_printf(s
, ",gid=%u", hypfs_info
->gid
);
271 static int hypfs_fill_super(struct super_block
*sb
, void *data
, int silent
)
273 struct inode
*root_inode
;
274 struct dentry
*root_dentry
;
276 struct hypfs_sb_info
*sbi
;
278 sbi
= kzalloc(sizeof(struct hypfs_sb_info
), GFP_KERNEL
);
281 mutex_init(&sbi
->lock
);
282 sbi
->uid
= current_uid();
283 sbi
->gid
= current_gid();
285 sb
->s_blocksize
= PAGE_CACHE_SIZE
;
286 sb
->s_blocksize_bits
= PAGE_CACHE_SHIFT
;
287 sb
->s_magic
= HYPFS_MAGIC
;
288 sb
->s_op
= &hypfs_s_ops
;
289 if (hypfs_parse_options(data
, sb
))
291 root_inode
= hypfs_make_inode(sb
, S_IFDIR
| 0755);
294 root_inode
->i_op
= &simple_dir_inode_operations
;
295 root_inode
->i_fop
= &simple_dir_operations
;
296 sb
->s_root
= root_dentry
= d_make_root(root_inode
);
300 rc
= hypfs_vm_create_files(sb
, root_dentry
);
302 rc
= hypfs_diag_create_files(sb
, root_dentry
);
305 sbi
->update_file
= hypfs_create_update_file(sb
, root_dentry
);
306 if (IS_ERR(sbi
->update_file
))
307 return PTR_ERR(sbi
->update_file
);
308 hypfs_update_update(sb
);
309 pr_info("Hypervisor filesystem mounted\n");
313 static struct dentry
*hypfs_mount(struct file_system_type
*fst
, int flags
,
314 const char *devname
, void *data
)
316 return mount_single(fst
, flags
, data
, hypfs_fill_super
);
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 if (sb_info
->update_file
)
326 hypfs_remove(sb_info
->update_file
);
327 kfree(sb
->s_fs_info
);
328 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
, umode_t mode
)
336 struct dentry
*dentry
;
339 mutex_lock(&parent
->d_inode
->i_mutex
);
340 dentry
= lookup_one_len(name
, parent
, strlen(name
));
341 if (IS_ERR(dentry
)) {
342 dentry
= ERR_PTR(-ENOMEM
);
345 inode
= hypfs_make_inode(sb
, mode
);
348 dentry
= ERR_PTR(-ENOMEM
);
352 inode
->i_fop
= &hypfs_file_ops
;
354 inode
->i_size
= strlen(data
);
357 } else if (S_ISDIR(mode
)) {
358 inode
->i_op
= &simple_dir_inode_operations
;
359 inode
->i_fop
= &simple_dir_operations
;
360 inc_nlink(parent
->d_inode
);
363 inode
->i_private
= data
;
364 d_instantiate(dentry
, inode
);
367 mutex_unlock(&parent
->d_inode
->i_mutex
);
371 struct dentry
*hypfs_mkdir(struct super_block
*sb
, struct dentry
*parent
,
374 struct dentry
*dentry
;
376 dentry
= hypfs_create_file(sb
, parent
, name
, NULL
, S_IFDIR
| DIR_MODE
);
379 hypfs_add_dentry(dentry
);
383 static struct dentry
*hypfs_create_update_file(struct super_block
*sb
,
386 struct dentry
*dentry
;
388 dentry
= hypfs_create_file(sb
, dir
, "update", NULL
,
389 S_IFREG
| UPDATE_FILE_MODE
);
391 * We do not put the update file on the 'delete' list with
392 * hypfs_add_dentry(), since it should not be removed when the tree
398 struct dentry
*hypfs_create_u64(struct super_block
*sb
, struct dentry
*dir
,
399 const char *name
, __u64 value
)
403 struct dentry
*dentry
;
405 snprintf(tmp
, TMP_SIZE
, "%llu\n", (unsigned long long int)value
);
406 buffer
= kstrdup(tmp
, GFP_KERNEL
);
408 return ERR_PTR(-ENOMEM
);
410 hypfs_create_file(sb
, dir
, name
, buffer
, S_IFREG
| REG_FILE_MODE
);
411 if (IS_ERR(dentry
)) {
413 return ERR_PTR(-ENOMEM
);
415 hypfs_add_dentry(dentry
);
419 struct dentry
*hypfs_create_str(struct super_block
*sb
, struct dentry
*dir
,
420 const char *name
, char *string
)
423 struct dentry
*dentry
;
425 buffer
= kmalloc(strlen(string
) + 2, GFP_KERNEL
);
427 return ERR_PTR(-ENOMEM
);
428 sprintf(buffer
, "%s\n", string
);
430 hypfs_create_file(sb
, dir
, name
, buffer
, S_IFREG
| REG_FILE_MODE
);
431 if (IS_ERR(dentry
)) {
433 return ERR_PTR(-ENOMEM
);
435 hypfs_add_dentry(dentry
);
439 static const struct file_operations hypfs_file_ops
= {
441 .release
= hypfs_release
,
442 .read
= do_sync_read
,
443 .write
= do_sync_write
,
444 .aio_read
= hypfs_aio_read
,
445 .aio_write
= hypfs_aio_write
,
449 static struct file_system_type hypfs_type
= {
450 .owner
= THIS_MODULE
,
451 .name
= "s390_hypfs",
452 .mount
= hypfs_mount
,
453 .kill_sb
= hypfs_kill_super
456 static const struct super_operations hypfs_s_ops
= {
457 .statfs
= simple_statfs
,
458 .evict_inode
= hypfs_evict_inode
,
459 .show_options
= hypfs_show_options
,
462 static struct kobject
*s390_kobj
;
464 static int __init
hypfs_init(void)
468 rc
= hypfs_dbfs_init();
471 if (hypfs_diag_init()) {
475 if (hypfs_vm_init()) {
477 goto fail_hypfs_diag_exit
;
479 s390_kobj
= kobject_create_and_add("s390", hypervisor_kobj
);
482 goto fail_hypfs_vm_exit
;
484 rc
= register_filesystem(&hypfs_type
);
486 goto fail_filesystem
;
490 kobject_put(s390_kobj
);
493 fail_hypfs_diag_exit
:
497 pr_err("Initialization of hypfs failed with rc=%i\n", rc
);
501 static void __exit
hypfs_exit(void)
506 unregister_filesystem(&hypfs_type
);
507 kobject_put(s390_kobj
);
510 module_init(hypfs_init
)
511 module_exit(hypfs_exit
)
513 MODULE_LICENSE("GPL");
514 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
515 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");