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NIU: Implement discard counters
[linux-2.6/verdex.git] / fs / hppfs / hppfs.c
blob2b3d1828db99a2a68a3e5fef961f0f6740cf04c8
1 /*
2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6 #include <linux/ctype.h>
7 #include <linux/dcache.h>
8 #include <linux/file.h>
9 #include <linux/fs.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/list.h>
13 #include <linux/module.h>
14 #include <linux/mount.h>
15 #include <linux/slab.h>
16 #include <linux/statfs.h>
17 #include <linux/types.h>
18 #include <asm/uaccess.h>
19 #include "os.h"
20
21 static struct inode *get_inode(struct super_block *, struct dentry *);
22
23 struct hppfs_data {
24 struct list_head list;
25 char contents[PAGE_SIZE - sizeof(struct list_head)];
26 };
27
28 struct hppfs_private {
29 struct file *proc_file;
30 int host_fd;
31 loff_t len;
32 struct hppfs_data *contents;
33 };
34
35 struct hppfs_inode_info {
36 struct dentry *proc_dentry;
37 struct inode vfs_inode;
38 };
39
40 static inline struct hppfs_inode_info *HPPFS_I(struct inode *inode)
41 {
42 return container_of(inode, struct hppfs_inode_info, vfs_inode);
43 }
44
45 #define HPPFS_SUPER_MAGIC 0xb00000ee
46
47 static const struct super_operations hppfs_sbops;
48
49 static int is_pid(struct dentry *dentry)
50 {
51 struct super_block *sb;
52 int i;
53
54 sb = dentry->d_sb;
55 if (dentry->d_parent != sb->s_root)
56 return 0;
57
58 for (i = 0; i < dentry->d_name.len; i++) {
59 if (!isdigit(dentry->d_name.name[i]))
60 return 0;
61 }
62 return 1;
63 }
64
65 static char *dentry_name(struct dentry *dentry, int extra)
66 {
67 struct dentry *parent;
68 char *root, *name;
69 const char *seg_name;
70 int len, seg_len;
71
72 len = 0;
73 parent = dentry;
74 while (parent->d_parent != parent) {
75 if (is_pid(parent))
76 len += strlen("pid") + 1;
77 else len += parent->d_name.len + 1;
78 parent = parent->d_parent;
79 }
80
81 root = "proc";
82 len += strlen(root);
83 name = kmalloc(len + extra + 1, GFP_KERNEL);
84 if (name == NULL)
85 return NULL;
86
87 name[len] = '\0';
88 parent = dentry;
89 while (parent->d_parent != parent) {
90 if (is_pid(parent)) {
91 seg_name = "pid";
92 seg_len = strlen("pid");
93 }
94 else {
95 seg_name = parent->d_name.name;
96 seg_len = parent->d_name.len;
97 }
98
99 len -= seg_len + 1;
100 name[len] = '/';
101 strncpy(&name[len + 1], seg_name, seg_len);
102 parent = parent->d_parent;
103 }
104 strncpy(name, root, strlen(root));
105 return name;
106 }
107
108 static int file_removed(struct dentry *dentry, const char *file)
109 {
110 char *host_file;
111 int extra, fd;
112
113 extra = 0;
114 if (file != NULL)
115 extra += strlen(file) + 1;
116
117 host_file = dentry_name(dentry, extra + strlen("/remove"));
118 if (host_file == NULL) {
119 printk(KERN_ERR "file_removed : allocation failed\n");
120 return -ENOMEM;
121 }
122
123 if (file != NULL) {
124 strcat(host_file, "/");
125 strcat(host_file, file);
126 }
127 strcat(host_file, "/remove");
128
129 fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
130 kfree(host_file);
131 if (fd > 0) {
132 os_close_file(fd);
133 return 1;
134 }
135 return 0;
136 }
137
138 static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
139 struct nameidata *nd)
140 {
141 struct dentry *proc_dentry, *new, *parent;
142 struct inode *inode;
143 int err, deleted;
144
145 deleted = file_removed(dentry, NULL);
146 if (deleted < 0)
147 return ERR_PTR(deleted);
148 else if (deleted)
149 return ERR_PTR(-ENOENT);
150
151 err = -ENOMEM;
152 parent = HPPFS_I(ino)->proc_dentry;
153 mutex_lock(&parent->d_inode->i_mutex);
154 proc_dentry = d_lookup(parent, &dentry->d_name);
155 if (proc_dentry == NULL) {
156 proc_dentry = d_alloc(parent, &dentry->d_name);
157 if (proc_dentry == NULL) {
158 mutex_unlock(&parent->d_inode->i_mutex);
159 goto out;
160 }
161 new = (*parent->d_inode->i_op->lookup)(parent->d_inode,
162 proc_dentry, NULL);
163 if (new) {
164 dput(proc_dentry);
165 proc_dentry = new;
166 }
167 }
168 mutex_unlock(&parent->d_inode->i_mutex);
169
170 if (IS_ERR(proc_dentry))
171 return proc_dentry;
172
173 err = -ENOMEM;
174 inode = get_inode(ino->i_sb, proc_dentry);
175 if (!inode)
176 goto out_dput;
177
178 d_add(dentry, inode);
179 return NULL;
180
181 out_dput:
182 dput(proc_dentry);
183 out:
184 return ERR_PTR(err);
185 }
186
187 static const struct inode_operations hppfs_file_iops = {
188 };
189
190 static ssize_t read_proc(struct file *file, char __user *buf, ssize_t count,
191 loff_t *ppos, int is_user)
192 {
193 ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
194 ssize_t n;
195
196 read = file->f_path.dentry->d_inode->i_fop->read;
197
198 if (!is_user)
199 set_fs(KERNEL_DS);
200
201 n = (*read)(file, buf, count, &file->f_pos);
202
203 if (!is_user)
204 set_fs(USER_DS);
205
206 if (ppos)
207 *ppos = file->f_pos;
208 return n;
209 }
210
211 static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
212 {
213 ssize_t n;
214 int cur, err;
215 char *new_buf;
216
217 n = -ENOMEM;
218 new_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
219 if (new_buf == NULL) {
220 printk(KERN_ERR "hppfs_read_file : kmalloc failed\n");
221 goto out;
222 }
223 n = 0;
224 while (count > 0) {
225 cur = min_t(ssize_t, count, PAGE_SIZE);
226 err = os_read_file(fd, new_buf, cur);
227 if (err < 0) {
228 printk(KERN_ERR "hppfs_read : read failed, "
229 "errno = %d\n", err);
230 n = err;
231 goto out_free;
232 } else if (err == 0)
233 break;
234
235 if (copy_to_user(buf, new_buf, err)) {
236 n = -EFAULT;
237 goto out_free;
238 }
239 n += err;
240 count -= err;
241 }
242 out_free:
243 kfree(new_buf);
244 out:
245 return n;
246 }
247
248 static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
249 loff_t *ppos)
250 {
251 struct hppfs_private *hppfs = file->private_data;
252 struct hppfs_data *data;
253 loff_t off;
254 int err;
255
256 if (hppfs->contents != NULL) {
257 int rem;
258
259 if (*ppos >= hppfs->len)
260 return 0;
261
262 data = hppfs->contents;
263 off = *ppos;
264 while (off >= sizeof(data->contents)) {
265 data = list_entry(data->list.next, struct hppfs_data,
266 list);
267 off -= sizeof(data->contents);
268 }
269
270 if (off + count > hppfs->len)
271 count = hppfs->len - off;
272 rem = copy_to_user(buf, &data->contents[off], count);
273 *ppos += count - rem;
274 if (rem > 0)
275 return -EFAULT;
276 } else if (hppfs->host_fd != -1) {
277 err = os_seek_file(hppfs->host_fd, *ppos);
278 if (err) {
279 printk(KERN_ERR "hppfs_read : seek failed, "
280 "errno = %d\n", err);
281 return err;
282 }
283 count = hppfs_read_file(hppfs->host_fd, buf, count);
284 if (count > 0)
285 *ppos += count;
286 }
287 else count = read_proc(hppfs->proc_file, buf, count, ppos, 1);
288
289 return count;
290 }
291
292 static ssize_t hppfs_write(struct file *file, const char __user *buf,
293 size_t len, loff_t *ppos)
294 {
295 struct hppfs_private *data = file->private_data;
296 struct file *proc_file = data->proc_file;
297 ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
298
299 write = proc_file->f_path.dentry->d_inode->i_fop->write;
300 return (*write)(proc_file, buf, len, ppos);
301 }
302
303 static int open_host_sock(char *host_file, int *filter_out)
304 {
305 char *end;
306 int fd;
307
308 end = &host_file[strlen(host_file)];
309 strcpy(end, "/rw");
310 *filter_out = 1;
311 fd = os_connect_socket(host_file);
312 if (fd > 0)
313 return fd;
314
315 strcpy(end, "/r");
316 *filter_out = 0;
317 fd = os_connect_socket(host_file);
318 return fd;
319 }
320
321 static void free_contents(struct hppfs_data *head)
322 {
323 struct hppfs_data *data;
324 struct list_head *ele, *next;
325
326 if (head == NULL)
327 return;
328
329 list_for_each_safe(ele, next, &head->list) {
330 data = list_entry(ele, struct hppfs_data, list);
331 kfree(data);
332 }
333 kfree(head);
334 }
335
336 static struct hppfs_data *hppfs_get_data(int fd, int filter,
337 struct file *proc_file,
338 struct file *hppfs_file,
339 loff_t *size_out)
340 {
341 struct hppfs_data *data, *new, *head;
342 int n, err;
343
344 err = -ENOMEM;
345 data = kmalloc(sizeof(*data), GFP_KERNEL);
346 if (data == NULL) {
347 printk(KERN_ERR "hppfs_get_data : head allocation failed\n");
348 goto failed;
349 }
350
351 INIT_LIST_HEAD(&data->list);
352
353 head = data;
354 *size_out = 0;
355
356 if (filter) {
357 while ((n = read_proc(proc_file, data->contents,
358 sizeof(data->contents), NULL, 0)) > 0)
359 os_write_file(fd, data->contents, n);
360 err = os_shutdown_socket(fd, 0, 1);
361 if (err) {
362 printk(KERN_ERR "hppfs_get_data : failed to shut down "
363 "socket\n");
364 goto failed_free;
365 }
366 }
367 while (1) {
368 n = os_read_file(fd, data->contents, sizeof(data->contents));
369 if (n < 0) {
370 err = n;
371 printk(KERN_ERR "hppfs_get_data : read failed, "
372 "errno = %d\n", err);
373 goto failed_free;
374 } else if (n == 0)
375 break;
376
377 *size_out += n;
378
379 if (n < sizeof(data->contents))
380 break;
381
382 new = kmalloc(sizeof(*data), GFP_KERNEL);
383 if (new == 0) {
384 printk(KERN_ERR "hppfs_get_data : data allocation "
385 "failed\n");
386 err = -ENOMEM;
387 goto failed_free;
388 }
389
390 INIT_LIST_HEAD(&new->list);
391 list_add(&new->list, &data->list);
392 data = new;
393 }
394 return head;
395
396 failed_free:
397 free_contents(head);
398 failed:
399 return ERR_PTR(err);
400 }
401
402 static struct hppfs_private *hppfs_data(void)
403 {
404 struct hppfs_private *data;
405
406 data = kmalloc(sizeof(*data), GFP_KERNEL);
407 if (data == NULL)
408 return data;
409
410 *data = ((struct hppfs_private ) { .host_fd = -1,
411 .len = -1,
412 .contents = NULL } );
413 return data;
414 }
415
416 static int file_mode(int fmode)
417 {
418 if (fmode == (FMODE_READ | FMODE_WRITE))
419 return O_RDWR;
420 if (fmode == FMODE_READ)
421 return O_RDONLY;
422 if (fmode == FMODE_WRITE)
423 return O_WRONLY;
424 return 0;
425 }
426
427 static int hppfs_open(struct inode *inode, struct file *file)
428 {
429 struct hppfs_private *data;
430 struct vfsmount *proc_mnt;
431 struct dentry *proc_dentry;
432 char *host_file;
433 int err, fd, type, filter;
434
435 err = -ENOMEM;
436 data = hppfs_data();
437 if (data == NULL)
438 goto out;
439
440 host_file = dentry_name(file->f_path.dentry, strlen("/rw"));
441 if (host_file == NULL)
442 goto out_free2;
443
444 proc_dentry = HPPFS_I(inode)->proc_dentry;
445 proc_mnt = inode->i_sb->s_fs_info;
446
447 /* XXX This isn't closed anywhere */
448 data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
449 file_mode(file->f_mode));
450 err = PTR_ERR(data->proc_file);
451 if (IS_ERR(data->proc_file))
452 goto out_free1;
453
454 type = os_file_type(host_file);
455 if (type == OS_TYPE_FILE) {
456 fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
457 if (fd >= 0)
458 data->host_fd = fd;
459 else
460 printk(KERN_ERR "hppfs_open : failed to open '%s', "
461 "errno = %d\n", host_file, -fd);
462
463 data->contents = NULL;
464 } else if (type == OS_TYPE_DIR) {
465 fd = open_host_sock(host_file, &filter);
466 if (fd > 0) {
467 data->contents = hppfs_get_data(fd, filter,
468 data->proc_file,
469 file, &data->len);
470 if (!IS_ERR(data->contents))
471 data->host_fd = fd;
472 } else
473 printk(KERN_ERR "hppfs_open : failed to open a socket "
474 "in '%s', errno = %d\n", host_file, -fd);
475 }
476 kfree(host_file);
477
478 file->private_data = data;
479 return 0;
480
481 out_free1:
482 kfree(host_file);
483 out_free2:
484 free_contents(data->contents);
485 kfree(data);
486 out:
487 return err;
488 }
489
490 static int hppfs_dir_open(struct inode *inode, struct file *file)
491 {
492 struct hppfs_private *data;
493 struct vfsmount *proc_mnt;
494 struct dentry *proc_dentry;
495 int err;
496
497 err = -ENOMEM;
498 data = hppfs_data();
499 if (data == NULL)
500 goto out;
501
502 proc_dentry = HPPFS_I(inode)->proc_dentry;
503 proc_mnt = inode->i_sb->s_fs_info;
504 data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
505 file_mode(file->f_mode));
506 err = PTR_ERR(data->proc_file);
507 if (IS_ERR(data->proc_file))
508 goto out_free;
509
510 file->private_data = data;
511 return 0;
512
513 out_free:
514 kfree(data);
515 out:
516 return err;
517 }
518
519 static loff_t hppfs_llseek(struct file *file, loff_t off, int where)
520 {
521 struct hppfs_private *data = file->private_data;
522 struct file *proc_file = data->proc_file;
523 loff_t (*llseek)(struct file *, loff_t, int);
524 loff_t ret;
525
526 llseek = proc_file->f_path.dentry->d_inode->i_fop->llseek;
527 if (llseek != NULL) {
528 ret = (*llseek)(proc_file, off, where);
529 if (ret < 0)
530 return ret;
531 }
532
533 return default_llseek(file, off, where);
534 }
535
536 static const struct file_operations hppfs_file_fops = {
537 .owner = NULL,
538 .llseek = hppfs_llseek,
539 .read = hppfs_read,
540 .write = hppfs_write,
541 .open = hppfs_open,
542 };
543
544 struct hppfs_dirent {
545 void *vfs_dirent;
546 filldir_t filldir;
547 struct dentry *dentry;
548 };
549
550 static int hppfs_filldir(void *d, const char *name, int size,
551 loff_t offset, u64 inode, unsigned int type)
552 {
553 struct hppfs_dirent *dirent = d;
554
555 if (file_removed(dirent->dentry, name))
556 return 0;
557
558 return (*dirent->filldir)(dirent->vfs_dirent, name, size, offset,
559 inode, type);
560 }
561
562 static int hppfs_readdir(struct file *file, void *ent, filldir_t filldir)
563 {
564 struct hppfs_private *data = file->private_data;
565 struct file *proc_file = data->proc_file;
566 int (*readdir)(struct file *, void *, filldir_t);
567 struct hppfs_dirent dirent = ((struct hppfs_dirent)
568 { .vfs_dirent = ent,
569 .filldir = filldir,
570 .dentry = file->f_path.dentry
571 });
572 int err;
573
574 readdir = proc_file->f_path.dentry->d_inode->i_fop->readdir;
575
576 proc_file->f_pos = file->f_pos;
577 err = (*readdir)(proc_file, &dirent, hppfs_filldir);
578 file->f_pos = proc_file->f_pos;
579
580 return err;
581 }
582
583 static int hppfs_fsync(struct file *file, struct dentry *dentry, int datasync)
584 {
585 return 0;
586 }
587
588 static const struct file_operations hppfs_dir_fops = {
589 .owner = NULL,
590 .readdir = hppfs_readdir,
591 .open = hppfs_dir_open,
592 .fsync = hppfs_fsync,
593 };
594
595 static int hppfs_statfs(struct dentry *dentry, struct kstatfs *sf)
596 {
597 sf->f_blocks = 0;
598 sf->f_bfree = 0;
599 sf->f_bavail = 0;
600 sf->f_files = 0;
601 sf->f_ffree = 0;
602 sf->f_type = HPPFS_SUPER_MAGIC;
603 return 0;
604 }
605
606 static struct inode *hppfs_alloc_inode(struct super_block *sb)
607 {
608 struct hppfs_inode_info *hi;
609
610 hi = kmalloc(sizeof(*hi), GFP_KERNEL);
611 if (!hi)
612 return NULL;
613
614 hi->proc_dentry = NULL;
615 inode_init_once(&hi->vfs_inode);
616 return &hi->vfs_inode;
617 }
618
619 void hppfs_delete_inode(struct inode *ino)
620 {
621 dput(HPPFS_I(ino)->proc_dentry);
622 mntput(ino->i_sb->s_fs_info);
623
624 clear_inode(ino);
625 }
626
627 static void hppfs_destroy_inode(struct inode *inode)
628 {
629 kfree(HPPFS_I(inode));
630 }
631
632 static const struct super_operations hppfs_sbops = {
633 .alloc_inode = hppfs_alloc_inode,
634 .destroy_inode = hppfs_destroy_inode,
635 .delete_inode = hppfs_delete_inode,
636 .statfs = hppfs_statfs,
637 };
638
639 static int hppfs_readlink(struct dentry *dentry, char __user *buffer,
640 int buflen)
641 {
642 struct dentry *proc_dentry;
643
644 proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
645 return proc_dentry->d_inode->i_op->readlink(proc_dentry, buffer,
646 buflen);
647 }
648
649 static void *hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
650 {
651 struct dentry *proc_dentry;
652
653 proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
654
655 return proc_dentry->d_inode->i_op->follow_link(proc_dentry, nd);
656 }
657
658 static const struct inode_operations hppfs_dir_iops = {
659 .lookup = hppfs_lookup,
660 };
661
662 static const struct inode_operations hppfs_link_iops = {
663 .readlink = hppfs_readlink,
664 .follow_link = hppfs_follow_link,
665 };
666
667 static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
668 {
669 struct inode *proc_ino = dentry->d_inode;
670 struct inode *inode = new_inode(sb);
671
672 if (!inode)
673 return ERR_PTR(-ENOMEM);
674
675 if (S_ISDIR(dentry->d_inode->i_mode)) {
676 inode->i_op = &hppfs_dir_iops;
677 inode->i_fop = &hppfs_dir_fops;
678 } else if (S_ISLNK(dentry->d_inode->i_mode)) {
679 inode->i_op = &hppfs_link_iops;
680 inode->i_fop = &hppfs_file_fops;
681 } else {
682 inode->i_op = &hppfs_file_iops;
683 inode->i_fop = &hppfs_file_fops;
684 }
685
686 HPPFS_I(inode)->proc_dentry = dget(dentry);
687
688 inode->i_uid = proc_ino->i_uid;
689 inode->i_gid = proc_ino->i_gid;
690 inode->i_atime = proc_ino->i_atime;
691 inode->i_mtime = proc_ino->i_mtime;
692 inode->i_ctime = proc_ino->i_ctime;
693 inode->i_ino = proc_ino->i_ino;
694 inode->i_mode = proc_ino->i_mode;
695 inode->i_nlink = proc_ino->i_nlink;
696 inode->i_size = proc_ino->i_size;
697 inode->i_blocks = proc_ino->i_blocks;
698
699 return inode;
700 }
701
702 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
703 {
704 struct inode *root_inode;
705 struct vfsmount *proc_mnt;
706 int err = -ENOENT;
707
708 proc_mnt = do_kern_mount("proc", 0, "proc", NULL);
709 if (IS_ERR(proc_mnt))
710 goto out;
711
712 sb->s_blocksize = 1024;
713 sb->s_blocksize_bits = 10;
714 sb->s_magic = HPPFS_SUPER_MAGIC;
715 sb->s_op = &hppfs_sbops;
716 sb->s_fs_info = proc_mnt;
717
718 err = -ENOMEM;
719 root_inode = get_inode(sb, proc_mnt->mnt_sb->s_root);
720 if (!root_inode)
721 goto out_mntput;
722
723 sb->s_root = d_alloc_root(root_inode);
724 if (!sb->s_root)
725 goto out_iput;
726
727 return 0;
728
729 out_iput:
730 iput(root_inode);
731 out_mntput:
732 mntput(proc_mnt);
733 out:
734 return(err);
735 }
736
737 static int hppfs_read_super(struct file_system_type *type,
738 int flags, const char *dev_name,
739 void *data, struct vfsmount *mnt)
740 {
741 return get_sb_nodev(type, flags, data, hppfs_fill_super, mnt);
742 }
743
744 static struct file_system_type hppfs_type = {
745 .owner = THIS_MODULE,
746 .name = "hppfs",
747 .get_sb = hppfs_read_super,
748 .kill_sb = kill_anon_super,
749 .fs_flags = 0,
750 };
751
752 static int __init init_hppfs(void)
753 {
754 return register_filesystem(&hppfs_type);
755 }
756
757 static void __exit exit_hppfs(void)
758 {
759 unregister_filesystem(&hppfs_type);
760 }
761
762 module_init(init_hppfs)
763 module_exit(exit_hppfs)
764 MODULE_LICENSE("GPL");
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