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 mutex_lock(&parent
->d_inode
->i_mutex
);
76 if (hypfs_positive(dentry
)) {
77 if (S_ISDIR(dentry
->d_inode
->i_mode
))
78 simple_rmdir(parent
->d_inode
, dentry
);
80 simple_unlink(parent
->d_inode
, dentry
);
84 mutex_unlock(&parent
->d_inode
->i_mutex
);
87 static void hypfs_delete_tree(struct dentry
*root
)
89 while (hypfs_last_dentry
) {
90 struct dentry
*next_dentry
;
91 next_dentry
= hypfs_last_dentry
->d_fsdata
;
92 hypfs_remove(hypfs_last_dentry
);
93 hypfs_last_dentry
= next_dentry
;
97 static struct inode
*hypfs_make_inode(struct super_block
*sb
, umode_t mode
)
99 struct inode
*ret
= new_inode(sb
);
102 struct hypfs_sb_info
*hypfs_info
= sb
->s_fs_info
;
103 ret
->i_ino
= get_next_ino();
105 ret
->i_uid
= hypfs_info
->uid
;
106 ret
->i_gid
= hypfs_info
->gid
;
107 ret
->i_atime
= ret
->i_mtime
= ret
->i_ctime
= CURRENT_TIME
;
114 static void hypfs_evict_inode(struct inode
*inode
)
117 kfree(inode
->i_private
);
120 static int hypfs_open(struct inode
*inode
, struct file
*filp
)
122 char *data
= filp
->f_path
.dentry
->d_inode
->i_private
;
123 struct hypfs_sb_info
*fs_info
;
125 if (filp
->f_mode
& FMODE_WRITE
) {
126 if (!(inode
->i_mode
& S_IWUGO
))
129 if (filp
->f_mode
& FMODE_READ
) {
130 if (!(inode
->i_mode
& S_IRUGO
))
134 fs_info
= inode
->i_sb
->s_fs_info
;
136 mutex_lock(&fs_info
->lock
);
137 filp
->private_data
= kstrdup(data
, GFP_KERNEL
);
138 if (!filp
->private_data
) {
139 mutex_unlock(&fs_info
->lock
);
142 mutex_unlock(&fs_info
->lock
);
144 return nonseekable_open(inode
, filp
);
147 static ssize_t
hypfs_aio_read(struct kiocb
*iocb
, const struct iovec
*iov
,
148 unsigned long nr_segs
, loff_t offset
)
152 struct file
*filp
= iocb
->ki_filp
;
154 char __user
*buf
= iov
[0].iov_base
;
155 size_t count
= iov
[0].iov_len
;
160 data
= filp
->private_data
;
161 ret
= simple_read_from_buffer(buf
, count
, &offset
, data
, strlen(data
));
170 static ssize_t
hypfs_aio_write(struct kiocb
*iocb
, const struct iovec
*iov
,
171 unsigned long nr_segs
, loff_t offset
)
174 struct super_block
*sb
;
175 struct hypfs_sb_info
*fs_info
;
176 size_t count
= iov_length(iov
, nr_segs
);
178 sb
= iocb
->ki_filp
->f_path
.dentry
->d_inode
->i_sb
;
179 fs_info
= sb
->s_fs_info
;
181 * Currently we only allow one update per second for two reasons:
182 * 1. diag 204 is VERY expensive
183 * 2. If several processes do updates in parallel and then read the
184 * hypfs data, the likelihood of collisions is reduced, if we restrict
185 * the minimum update interval. A collision occurs, if during the
186 * data gathering of one process another process triggers an update
187 * If the first process wants to ensure consistent data, it has
188 * to restart data collection in this case.
190 mutex_lock(&fs_info
->lock
);
191 if (fs_info
->last_update
== get_seconds()) {
195 hypfs_delete_tree(sb
->s_root
);
197 rc
= hypfs_vm_create_files(sb
, sb
->s_root
);
199 rc
= hypfs_diag_create_files(sb
, sb
->s_root
);
201 pr_err("Updating the hypfs tree failed\n");
202 hypfs_delete_tree(sb
->s_root
);
205 hypfs_update_update(sb
);
208 mutex_unlock(&fs_info
->lock
);
212 static int hypfs_release(struct inode
*inode
, struct file
*filp
)
214 kfree(filp
->private_data
);
218 enum { opt_uid
, opt_gid
, opt_err
};
220 static const match_table_t hypfs_tokens
= {
226 static int hypfs_parse_options(char *options
, struct super_block
*sb
)
229 substring_t args
[MAX_OPT_ARGS
];
233 while ((str
= strsep(&options
, ",")) != NULL
) {
235 struct hypfs_sb_info
*hypfs_info
= sb
->s_fs_info
;
239 token
= match_token(str
, hypfs_tokens
, args
);
242 if (match_int(&args
[0], &option
))
244 hypfs_info
->uid
= option
;
247 if (match_int(&args
[0], &option
))
249 hypfs_info
->gid
= option
;
253 pr_err("%s is not a valid mount option\n", str
);
260 static int hypfs_show_options(struct seq_file
*s
, struct dentry
*root
)
262 struct hypfs_sb_info
*hypfs_info
= root
->d_sb
->s_fs_info
;
264 seq_printf(s
, ",uid=%u", hypfs_info
->uid
);
265 seq_printf(s
, ",gid=%u", hypfs_info
->gid
);
269 static int hypfs_fill_super(struct super_block
*sb
, void *data
, int silent
)
271 struct inode
*root_inode
;
272 struct dentry
*root_dentry
;
274 struct hypfs_sb_info
*sbi
;
276 sbi
= kzalloc(sizeof(struct hypfs_sb_info
), GFP_KERNEL
);
279 mutex_init(&sbi
->lock
);
280 sbi
->uid
= current_uid();
281 sbi
->gid
= current_gid();
283 sb
->s_blocksize
= PAGE_CACHE_SIZE
;
284 sb
->s_blocksize_bits
= PAGE_CACHE_SHIFT
;
285 sb
->s_magic
= HYPFS_MAGIC
;
286 sb
->s_op
= &hypfs_s_ops
;
287 if (hypfs_parse_options(data
, sb
))
289 root_inode
= hypfs_make_inode(sb
, S_IFDIR
| 0755);
292 root_inode
->i_op
= &simple_dir_inode_operations
;
293 root_inode
->i_fop
= &simple_dir_operations
;
294 sb
->s_root
= root_dentry
= d_make_root(root_inode
);
298 rc
= hypfs_vm_create_files(sb
, root_dentry
);
300 rc
= hypfs_diag_create_files(sb
, root_dentry
);
303 sbi
->update_file
= hypfs_create_update_file(sb
, root_dentry
);
304 if (IS_ERR(sbi
->update_file
))
305 return PTR_ERR(sbi
->update_file
);
306 hypfs_update_update(sb
);
307 pr_info("Hypervisor filesystem mounted\n");
311 static struct dentry
*hypfs_mount(struct file_system_type
*fst
, int flags
,
312 const char *devname
, void *data
)
314 return mount_single(fst
, flags
, data
, hypfs_fill_super
);
317 static void hypfs_kill_super(struct super_block
*sb
)
319 struct hypfs_sb_info
*sb_info
= sb
->s_fs_info
;
322 hypfs_delete_tree(sb
->s_root
);
323 if (sb_info
->update_file
)
324 hypfs_remove(sb_info
->update_file
);
325 kfree(sb
->s_fs_info
);
326 sb
->s_fs_info
= NULL
;
327 kill_litter_super(sb
);
330 static struct dentry
*hypfs_create_file(struct super_block
*sb
,
331 struct dentry
*parent
, const char *name
,
332 char *data
, umode_t mode
)
334 struct dentry
*dentry
;
337 mutex_lock(&parent
->d_inode
->i_mutex
);
338 dentry
= lookup_one_len(name
, parent
, strlen(name
));
339 if (IS_ERR(dentry
)) {
340 dentry
= ERR_PTR(-ENOMEM
);
343 inode
= hypfs_make_inode(sb
, mode
);
346 dentry
= ERR_PTR(-ENOMEM
);
350 inode
->i_fop
= &hypfs_file_ops
;
352 inode
->i_size
= strlen(data
);
355 } else if (S_ISDIR(mode
)) {
356 inode
->i_op
= &simple_dir_inode_operations
;
357 inode
->i_fop
= &simple_dir_operations
;
358 inc_nlink(parent
->d_inode
);
361 inode
->i_private
= data
;
362 d_instantiate(dentry
, inode
);
365 mutex_unlock(&parent
->d_inode
->i_mutex
);
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
);
381 static struct dentry
*hypfs_create_update_file(struct super_block
*sb
,
384 struct dentry
*dentry
;
386 dentry
= hypfs_create_file(sb
, dir
, "update", NULL
,
387 S_IFREG
| UPDATE_FILE_MODE
);
389 * We do not put the update file on the 'delete' list with
390 * hypfs_add_dentry(), since it should not be removed when the tree
396 struct dentry
*hypfs_create_u64(struct super_block
*sb
, struct dentry
*dir
,
397 const char *name
, __u64 value
)
401 struct dentry
*dentry
;
403 snprintf(tmp
, TMP_SIZE
, "%llu\n", (unsigned long long int)value
);
404 buffer
= kstrdup(tmp
, GFP_KERNEL
);
406 return ERR_PTR(-ENOMEM
);
408 hypfs_create_file(sb
, dir
, name
, buffer
, S_IFREG
| REG_FILE_MODE
);
409 if (IS_ERR(dentry
)) {
411 return ERR_PTR(-ENOMEM
);
413 hypfs_add_dentry(dentry
);
417 struct dentry
*hypfs_create_str(struct super_block
*sb
, struct dentry
*dir
,
418 const char *name
, char *string
)
421 struct dentry
*dentry
;
423 buffer
= kmalloc(strlen(string
) + 2, GFP_KERNEL
);
425 return ERR_PTR(-ENOMEM
);
426 sprintf(buffer
, "%s\n", string
);
428 hypfs_create_file(sb
, dir
, name
, buffer
, S_IFREG
| REG_FILE_MODE
);
429 if (IS_ERR(dentry
)) {
431 return ERR_PTR(-ENOMEM
);
433 hypfs_add_dentry(dentry
);
437 static const struct file_operations hypfs_file_ops
= {
439 .release
= hypfs_release
,
440 .read
= do_sync_read
,
441 .write
= do_sync_write
,
442 .aio_read
= hypfs_aio_read
,
443 .aio_write
= hypfs_aio_write
,
447 static struct file_system_type hypfs_type
= {
448 .owner
= THIS_MODULE
,
449 .name
= "s390_hypfs",
450 .mount
= hypfs_mount
,
451 .kill_sb
= hypfs_kill_super
454 static const struct super_operations hypfs_s_ops
= {
455 .statfs
= simple_statfs
,
456 .evict_inode
= hypfs_evict_inode
,
457 .show_options
= hypfs_show_options
,
460 static struct kobject
*s390_kobj
;
462 static int __init
hypfs_init(void)
466 rc
= hypfs_dbfs_init();
469 if (hypfs_diag_init()) {
473 if (hypfs_vm_init()) {
475 goto fail_hypfs_diag_exit
;
477 s390_kobj
= kobject_create_and_add("s390", hypervisor_kobj
);
480 goto fail_hypfs_vm_exit
;
482 rc
= register_filesystem(&hypfs_type
);
484 goto fail_filesystem
;
488 kobject_put(s390_kobj
);
491 fail_hypfs_diag_exit
:
495 pr_err("Initialization of hypfs failed with rc=%i\n", rc
);
499 static void __exit
hypfs_exit(void)
504 unregister_filesystem(&hypfs_type
);
505 kobject_put(s390_kobj
);
508 module_init(hypfs_init
)
509 module_exit(hypfs_exit
)
511 MODULE_LICENSE("GPL");
512 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
513 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");