2 * arch/s390/hypfs/inode.c
3 * Hypervisor filesystem for Linux on s390.
5 * Copyright IBM Corp. 2006, 2008
6 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
9 #define KMSG_COMPONENT "hypfs"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12 #include <linux/types.h>
13 #include <linux/errno.h>
15 #include <linux/namei.h>
16 #include <linux/vfs.h>
17 #include <linux/pagemap.h>
18 #include <linux/gfp.h>
19 #include <linux/time.h>
20 #include <linux/parser.h>
21 #include <linux/sysfs.h>
22 #include <linux/module.h>
23 #include <linux/seq_file.h>
24 #include <linux/mount.h>
25 #include <asm/ebcdic.h>
28 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
29 #define TMP_SIZE 64 /* size of temporary buffers */
31 static struct dentry
*hypfs_create_update_file(struct super_block
*sb
,
34 struct hypfs_sb_info
{
35 uid_t uid
; /* uid used for files and dirs */
36 gid_t gid
; /* gid used for files and dirs */
37 struct dentry
*update_file
; /* file to trigger update */
38 time_t last_update
; /* last update time in secs since 1970 */
39 struct mutex lock
; /* lock to protect update process */
42 static const struct file_operations hypfs_file_ops
;
43 static struct file_system_type hypfs_type
;
44 static struct super_operations hypfs_s_ops
;
46 /* start of list of all dentries, which have to be deleted on update */
47 static struct dentry
*hypfs_last_dentry
;
49 static void hypfs_update_update(struct super_block
*sb
)
51 struct hypfs_sb_info
*sb_info
= sb
->s_fs_info
;
52 struct inode
*inode
= sb_info
->update_file
->d_inode
;
54 sb_info
->last_update
= get_seconds();
55 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= CURRENT_TIME
;
58 /* directory tree removal functions */
60 static void hypfs_add_dentry(struct dentry
*dentry
)
62 dentry
->d_fsdata
= hypfs_last_dentry
;
63 hypfs_last_dentry
= dentry
;
66 static inline int hypfs_positive(struct dentry
*dentry
)
68 return dentry
->d_inode
&& !d_unhashed(dentry
);
71 static void hypfs_remove(struct dentry
*dentry
)
73 struct dentry
*parent
;
75 parent
= dentry
->d_parent
;
76 if (!parent
|| !parent
->d_inode
)
78 mutex_lock(&parent
->d_inode
->i_mutex
);
79 if (hypfs_positive(dentry
)) {
80 if (S_ISDIR(dentry
->d_inode
->i_mode
))
81 simple_rmdir(parent
->d_inode
, dentry
);
83 simple_unlink(parent
->d_inode
, dentry
);
87 mutex_unlock(&parent
->d_inode
->i_mutex
);
90 static void hypfs_delete_tree(struct dentry
*root
)
92 while (hypfs_last_dentry
) {
93 struct dentry
*next_dentry
;
94 next_dentry
= hypfs_last_dentry
->d_fsdata
;
95 hypfs_remove(hypfs_last_dentry
);
96 hypfs_last_dentry
= next_dentry
;
100 static struct inode
*hypfs_make_inode(struct super_block
*sb
, int mode
)
102 struct inode
*ret
= new_inode(sb
);
105 struct hypfs_sb_info
*hypfs_info
= sb
->s_fs_info
;
107 ret
->i_uid
= hypfs_info
->uid
;
108 ret
->i_gid
= hypfs_info
->gid
;
110 ret
->i_atime
= ret
->i_mtime
= ret
->i_ctime
= CURRENT_TIME
;
119 static void hypfs_drop_inode(struct inode
*inode
)
121 kfree(inode
->i_private
);
122 generic_delete_inode(inode
);
125 static int hypfs_open(struct inode
*inode
, struct file
*filp
)
127 char *data
= filp
->f_path
.dentry
->d_inode
->i_private
;
128 struct hypfs_sb_info
*fs_info
;
130 if (filp
->f_mode
& FMODE_WRITE
) {
131 if (!(inode
->i_mode
& S_IWUGO
))
134 if (filp
->f_mode
& FMODE_READ
) {
135 if (!(inode
->i_mode
& S_IRUGO
))
139 fs_info
= inode
->i_sb
->s_fs_info
;
141 mutex_lock(&fs_info
->lock
);
142 filp
->private_data
= kstrdup(data
, GFP_KERNEL
);
143 if (!filp
->private_data
) {
144 mutex_unlock(&fs_info
->lock
);
147 mutex_unlock(&fs_info
->lock
);
152 static ssize_t
hypfs_aio_read(struct kiocb
*iocb
, const struct iovec
*iov
,
153 unsigned long nr_segs
, loff_t offset
)
157 struct file
*filp
= iocb
->ki_filp
;
159 char __user
*buf
= iov
[0].iov_base
;
160 size_t count
= iov
[0].iov_len
;
165 data
= filp
->private_data
;
166 ret
= simple_read_from_buffer(buf
, count
, &offset
, data
, strlen(data
));
175 static ssize_t
hypfs_aio_write(struct kiocb
*iocb
, const struct iovec
*iov
,
176 unsigned long nr_segs
, loff_t offset
)
179 struct super_block
*sb
;
180 struct hypfs_sb_info
*fs_info
;
181 size_t count
= iov_length(iov
, nr_segs
);
183 sb
= iocb
->ki_filp
->f_path
.dentry
->d_inode
->i_sb
;
184 fs_info
= sb
->s_fs_info
;
186 * Currently we only allow one update per second for two reasons:
187 * 1. diag 204 is VERY expensive
188 * 2. If several processes do updates in parallel and then read the
189 * hypfs data, the likelihood of collisions is reduced, if we restrict
190 * the minimum update interval. A collision occurs, if during the
191 * data gathering of one process another process triggers an update
192 * If the first process wants to ensure consistent data, it has
193 * to restart data collection in this case.
195 mutex_lock(&fs_info
->lock
);
196 if (fs_info
->last_update
== get_seconds()) {
200 hypfs_delete_tree(sb
->s_root
);
202 rc
= hypfs_vm_create_files(sb
, sb
->s_root
);
204 rc
= hypfs_diag_create_files(sb
, sb
->s_root
);
206 pr_err("Updating the hypfs tree failed\n");
207 hypfs_delete_tree(sb
->s_root
);
210 hypfs_update_update(sb
);
213 mutex_unlock(&fs_info
->lock
);
217 static int hypfs_release(struct inode
*inode
, struct file
*filp
)
219 kfree(filp
->private_data
);
223 enum { opt_uid
, opt_gid
, opt_err
};
225 static const match_table_t hypfs_tokens
= {
231 static int hypfs_parse_options(char *options
, struct super_block
*sb
)
234 substring_t args
[MAX_OPT_ARGS
];
238 while ((str
= strsep(&options
, ",")) != NULL
) {
240 struct hypfs_sb_info
*hypfs_info
= sb
->s_fs_info
;
244 token
= match_token(str
, hypfs_tokens
, args
);
247 if (match_int(&args
[0], &option
))
249 hypfs_info
->uid
= option
;
252 if (match_int(&args
[0], &option
))
254 hypfs_info
->gid
= option
;
258 pr_err("%s is not a valid mount option\n", str
);
265 static int hypfs_show_options(struct seq_file
*s
, struct vfsmount
*mnt
)
267 struct hypfs_sb_info
*hypfs_info
= mnt
->mnt_sb
->s_fs_info
;
269 seq_printf(s
, ",uid=%u", hypfs_info
->uid
);
270 seq_printf(s
, ",gid=%u", hypfs_info
->gid
);
274 static int hypfs_fill_super(struct super_block
*sb
, void *data
, int silent
)
276 struct inode
*root_inode
;
277 struct dentry
*root_dentry
;
279 struct hypfs_sb_info
*sbi
;
281 sbi
= kzalloc(sizeof(struct hypfs_sb_info
), GFP_KERNEL
);
284 mutex_init(&sbi
->lock
);
285 sbi
->uid
= current_uid();
286 sbi
->gid
= current_gid();
288 sb
->s_blocksize
= PAGE_CACHE_SIZE
;
289 sb
->s_blocksize_bits
= PAGE_CACHE_SHIFT
;
290 sb
->s_magic
= HYPFS_MAGIC
;
291 sb
->s_op
= &hypfs_s_ops
;
292 if (hypfs_parse_options(data
, sb
)) {
296 root_inode
= hypfs_make_inode(sb
, S_IFDIR
| 0755);
301 root_inode
->i_op
= &simple_dir_inode_operations
;
302 root_inode
->i_fop
= &simple_dir_operations
;
303 root_dentry
= d_alloc_root(root_inode
);
310 rc
= hypfs_vm_create_files(sb
, root_dentry
);
312 rc
= hypfs_diag_create_files(sb
, root_dentry
);
315 sbi
->update_file
= hypfs_create_update_file(sb
, root_dentry
);
316 if (IS_ERR(sbi
->update_file
)) {
317 rc
= PTR_ERR(sbi
->update_file
);
320 hypfs_update_update(sb
);
321 sb
->s_root
= root_dentry
;
322 pr_info("Hypervisor filesystem mounted\n");
326 hypfs_delete_tree(root_dentry
);
327 d_genocide(root_dentry
);
334 static int hypfs_get_super(struct file_system_type
*fst
, int flags
,
335 const char *devname
, void *data
, struct vfsmount
*mnt
)
337 return get_sb_single(fst
, flags
, data
, hypfs_fill_super
, mnt
);
340 static void hypfs_kill_super(struct super_block
*sb
)
342 struct hypfs_sb_info
*sb_info
= sb
->s_fs_info
;
345 hypfs_delete_tree(sb
->s_root
);
346 hypfs_remove(sb_info
->update_file
);
347 kfree(sb
->s_fs_info
);
348 sb
->s_fs_info
= NULL
;
350 kill_litter_super(sb
);
353 static struct dentry
*hypfs_create_file(struct super_block
*sb
,
354 struct dentry
*parent
, const char *name
,
355 char *data
, mode_t mode
)
357 struct dentry
*dentry
;
362 qname
.len
= strlen(name
);
363 qname
.hash
= full_name_hash(name
, qname
.len
);
364 mutex_lock(&parent
->d_inode
->i_mutex
);
365 dentry
= lookup_one_len(name
, parent
, strlen(name
));
366 if (IS_ERR(dentry
)) {
367 dentry
= ERR_PTR(-ENOMEM
);
370 inode
= hypfs_make_inode(sb
, mode
);
373 dentry
= ERR_PTR(-ENOMEM
);
376 if (mode
& S_IFREG
) {
377 inode
->i_fop
= &hypfs_file_ops
;
379 inode
->i_size
= strlen(data
);
382 } else if (mode
& S_IFDIR
) {
383 inode
->i_op
= &simple_dir_inode_operations
;
384 inode
->i_fop
= &simple_dir_operations
;
385 parent
->d_inode
->i_nlink
++;
388 inode
->i_private
= data
;
389 d_instantiate(dentry
, inode
);
392 mutex_unlock(&parent
->d_inode
->i_mutex
);
396 struct dentry
*hypfs_mkdir(struct super_block
*sb
, struct dentry
*parent
,
399 struct dentry
*dentry
;
401 dentry
= hypfs_create_file(sb
, parent
, name
, NULL
, S_IFDIR
| DIR_MODE
);
404 hypfs_add_dentry(dentry
);
408 static struct dentry
*hypfs_create_update_file(struct super_block
*sb
,
411 struct dentry
*dentry
;
413 dentry
= hypfs_create_file(sb
, dir
, "update", NULL
,
414 S_IFREG
| UPDATE_FILE_MODE
);
416 * We do not put the update file on the 'delete' list with
417 * hypfs_add_dentry(), since it should not be removed when the tree
423 struct dentry
*hypfs_create_u64(struct super_block
*sb
, struct dentry
*dir
,
424 const char *name
, __u64 value
)
428 struct dentry
*dentry
;
430 snprintf(tmp
, TMP_SIZE
, "%lld\n", (unsigned long long int)value
);
431 buffer
= kstrdup(tmp
, GFP_KERNEL
);
433 return ERR_PTR(-ENOMEM
);
435 hypfs_create_file(sb
, dir
, name
, buffer
, S_IFREG
| REG_FILE_MODE
);
436 if (IS_ERR(dentry
)) {
438 return ERR_PTR(-ENOMEM
);
440 hypfs_add_dentry(dentry
);
444 struct dentry
*hypfs_create_str(struct super_block
*sb
, struct dentry
*dir
,
445 const char *name
, char *string
)
448 struct dentry
*dentry
;
450 buffer
= kmalloc(strlen(string
) + 2, GFP_KERNEL
);
452 return ERR_PTR(-ENOMEM
);
453 sprintf(buffer
, "%s\n", string
);
455 hypfs_create_file(sb
, dir
, name
, buffer
, S_IFREG
| REG_FILE_MODE
);
456 if (IS_ERR(dentry
)) {
458 return ERR_PTR(-ENOMEM
);
460 hypfs_add_dentry(dentry
);
464 static const struct file_operations hypfs_file_ops
= {
466 .release
= hypfs_release
,
467 .read
= do_sync_read
,
468 .write
= do_sync_write
,
469 .aio_read
= hypfs_aio_read
,
470 .aio_write
= hypfs_aio_write
,
473 static struct file_system_type hypfs_type
= {
474 .owner
= THIS_MODULE
,
475 .name
= "s390_hypfs",
476 .get_sb
= hypfs_get_super
,
477 .kill_sb
= hypfs_kill_super
480 static struct super_operations hypfs_s_ops
= {
481 .statfs
= simple_statfs
,
482 .drop_inode
= hypfs_drop_inode
,
483 .show_options
= hypfs_show_options
,
486 static struct kobject
*s390_kobj
;
488 static int __init
hypfs_init(void)
494 /* no diag 2fc, just exit */
497 if (hypfs_diag_init()) {
502 s390_kobj
= kobject_create_and_add("s390", hypervisor_kobj
);
507 rc
= register_filesystem(&hypfs_type
);
509 goto fail_filesystem
;
513 kobject_put(s390_kobj
);
518 pr_err("Initialization of hypfs failed with rc=%i\n", rc
);
522 static void __exit
hypfs_exit(void)
526 unregister_filesystem(&hypfs_type
);
527 kobject_put(s390_kobj
);
530 module_init(hypfs_init
)
531 module_exit(hypfs_exit
)
533 MODULE_LICENSE("GPL");
534 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
535 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");