xref: /openbmc/linux/fs/coda/dir.c (revision 9ac8d3fb)
1 
2 /*
3  * Directory operations for Coda filesystem
4  * Original version: (C) 1996 P. Braam and M. Callahan
5  * Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
6  *
7  * Carnegie Mellon encourages users to contribute improvements to
8  * the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
9  */
10 
11 #include <linux/types.h>
12 #include <linux/kernel.h>
13 #include <linux/time.h>
14 #include <linux/fs.h>
15 #include <linux/file.h>
16 #include <linux/stat.h>
17 #include <linux/errno.h>
18 #include <linux/string.h>
19 #include <linux/smp_lock.h>
20 
21 #include <asm/uaccess.h>
22 
23 #include <linux/coda.h>
24 #include <linux/coda_linux.h>
25 #include <linux/coda_psdev.h>
26 #include <linux/coda_fs_i.h>
27 #include <linux/coda_cache.h>
28 
29 #include "coda_int.h"
30 
31 /* dir inode-ops */
32 static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
33 static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
34 static int coda_link(struct dentry *old_dentry, struct inode *dir_inode,
35 		     struct dentry *entry);
36 static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
37 static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
38 			const char *symname);
39 static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
40 static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
41 static int coda_rename(struct inode *old_inode, struct dentry *old_dentry,
42                        struct inode *new_inode, struct dentry *new_dentry);
43 
44 /* dir file-ops */
45 static int coda_readdir(struct file *file, void *buf, filldir_t filldir);
46 
47 /* dentry ops */
48 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
49 static int coda_dentry_delete(struct dentry *);
50 
51 /* support routines */
52 static int coda_venus_readdir(struct file *coda_file, void *buf,
53 			      filldir_t filldir);
54 
55 /* same as fs/bad_inode.c */
56 static int coda_return_EIO(void)
57 {
58 	return -EIO;
59 }
60 #define CODA_EIO_ERROR ((void *) (coda_return_EIO))
61 
62 static struct dentry_operations coda_dentry_operations =
63 {
64 	.d_revalidate	= coda_dentry_revalidate,
65 	.d_delete	= coda_dentry_delete,
66 };
67 
68 const struct inode_operations coda_dir_inode_operations =
69 {
70 	.create		= coda_create,
71 	.lookup		= coda_lookup,
72 	.link		= coda_link,
73 	.unlink		= coda_unlink,
74 	.symlink	= coda_symlink,
75 	.mkdir		= coda_mkdir,
76 	.rmdir		= coda_rmdir,
77 	.mknod		= CODA_EIO_ERROR,
78 	.rename		= coda_rename,
79 	.permission	= coda_permission,
80 	.getattr	= coda_getattr,
81 	.setattr	= coda_setattr,
82 };
83 
84 const struct file_operations coda_dir_operations = {
85 	.llseek		= generic_file_llseek,
86 	.read		= generic_read_dir,
87 	.readdir	= coda_readdir,
88 	.open		= coda_open,
89 	.release	= coda_release,
90 	.fsync		= coda_fsync,
91 };
92 
93 
94 /* inode operations for directories */
95 /* access routines: lookup, readlink, permission */
96 static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struct nameidata *nd)
97 {
98 	struct inode *inode = NULL;
99 	struct CodaFid resfid = { { 0, } };
100 	int type = 0;
101 	int error = 0;
102 	const char *name = entry->d_name.name;
103 	size_t length = entry->d_name.len;
104 
105 	if (length > CODA_MAXNAMLEN) {
106 		printk(KERN_ERR "name too long: lookup, %s (%*s)\n",
107 		       coda_i2s(dir), (int)length, name);
108 		return ERR_PTR(-ENAMETOOLONG);
109 	}
110 
111 	/* control object, create inode on the fly */
112 	if (coda_isroot(dir) && coda_iscontrol(name, length)) {
113 		error = coda_cnode_makectl(&inode, dir->i_sb);
114 		type = CODA_NOCACHE;
115 		goto exit;
116 	}
117 
118 	lock_kernel();
119 
120 	error = venus_lookup(dir->i_sb, coda_i2f(dir), name, length,
121 			     &type, &resfid);
122 	if (!error)
123 		error = coda_cnode_make(&inode, &resfid, dir->i_sb);
124 
125 	unlock_kernel();
126 
127 	if (error && error != -ENOENT)
128 		return ERR_PTR(error);
129 
130 exit:
131 	entry->d_op = &coda_dentry_operations;
132 
133 	if (inode && (type & CODA_NOCACHE))
134 		coda_flag_inode(inode, C_VATTR | C_PURGE);
135 
136 	return d_splice_alias(inode, entry);
137 }
138 
139 
140 int coda_permission(struct inode *inode, int mask)
141 {
142         int error = 0;
143 
144 	mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
145 
146 	if (!mask)
147 		return 0;
148 
149 	if ((mask & MAY_EXEC) && !execute_ok(inode))
150 		return -EACCES;
151 
152 	lock_kernel();
153 
154 	if (coda_cache_check(inode, mask))
155 		goto out;
156 
157         error = venus_access(inode->i_sb, coda_i2f(inode), mask);
158 
159 	if (!error)
160 		coda_cache_enter(inode, mask);
161 
162  out:
163 	unlock_kernel();
164 	return error;
165 }
166 
167 
168 static inline void coda_dir_update_mtime(struct inode *dir)
169 {
170 #ifdef REQUERY_VENUS_FOR_MTIME
171 	/* invalidate the directory cnode's attributes so we refetch the
172 	 * attributes from venus next time the inode is referenced */
173 	coda_flag_inode(dir, C_VATTR);
174 #else
175 	/* optimistically we can also act as if our nose bleeds. The
176 	 * granularity of the mtime is coarse anyways so we might actually be
177 	 * right most of the time. Note: we only do this for directories. */
178 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
179 #endif
180 }
181 
182 /* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
183  * trick to fool GNU find's optimizations. If we can't be sure of the link
184  * (because of volume mount points) we set i_nlink to 1 which forces find
185  * to consider every child as a possible directory. We should also never
186  * see an increment or decrement for deleted directories where i_nlink == 0 */
187 static inline void coda_dir_inc_nlink(struct inode *dir)
188 {
189 	if (dir->i_nlink >= 2)
190 		inc_nlink(dir);
191 }
192 
193 static inline void coda_dir_drop_nlink(struct inode *dir)
194 {
195 	if (dir->i_nlink > 2)
196 		drop_nlink(dir);
197 }
198 
199 /* creation routines: create, mknod, mkdir, link, symlink */
200 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
201 {
202         int error=0;
203 	const char *name=de->d_name.name;
204 	int length=de->d_name.len;
205 	struct inode *inode;
206 	struct CodaFid newfid;
207 	struct coda_vattr attrs;
208 
209 	lock_kernel();
210 
211 	if (coda_isroot(dir) && coda_iscontrol(name, length)) {
212 		unlock_kernel();
213 		return -EPERM;
214 	}
215 
216 	error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
217 				0, mode, &newfid, &attrs);
218 
219         if ( error ) {
220 		unlock_kernel();
221 		d_drop(de);
222 		return error;
223 	}
224 
225 	inode = coda_iget(dir->i_sb, &newfid, &attrs);
226 	if ( IS_ERR(inode) ) {
227 		unlock_kernel();
228 		d_drop(de);
229 		return PTR_ERR(inode);
230 	}
231 
232 	/* invalidate the directory cnode's attributes */
233 	coda_dir_update_mtime(dir);
234 	unlock_kernel();
235 	d_instantiate(de, inode);
236 	return 0;
237 }
238 
239 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
240 {
241 	struct inode *inode;
242 	struct coda_vattr attrs;
243 	const char *name = de->d_name.name;
244 	int len = de->d_name.len;
245 	int error;
246 	struct CodaFid newfid;
247 
248 	lock_kernel();
249 
250 	if (coda_isroot(dir) && coda_iscontrol(name, len)) {
251 		unlock_kernel();
252 		return -EPERM;
253 	}
254 
255 	attrs.va_mode = mode;
256 	error = venus_mkdir(dir->i_sb, coda_i2f(dir),
257 			       name, len, &newfid, &attrs);
258 
259         if ( error ) {
260 		unlock_kernel();
261 		d_drop(de);
262 		return error;
263         }
264 
265 	inode = coda_iget(dir->i_sb, &newfid, &attrs);
266 	if ( IS_ERR(inode) ) {
267 		unlock_kernel();
268 		d_drop(de);
269 		return PTR_ERR(inode);
270 	}
271 
272 	/* invalidate the directory cnode's attributes */
273 	coda_dir_inc_nlink(dir);
274 	coda_dir_update_mtime(dir);
275 	unlock_kernel();
276 	d_instantiate(de, inode);
277 	return 0;
278 }
279 
280 /* try to make de an entry in dir_inodde linked to source_de */
281 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
282 	  struct dentry *de)
283 {
284 	struct inode *inode = source_de->d_inode;
285         const char * name = de->d_name.name;
286 	int len = de->d_name.len;
287 	int error;
288 
289 	lock_kernel();
290 
291 	if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
292 		unlock_kernel();
293 		return -EPERM;
294 	}
295 
296 	error = venus_link(dir_inode->i_sb, coda_i2f(inode),
297 			   coda_i2f(dir_inode), (const char *)name, len);
298 
299 	if (error) {
300 		d_drop(de);
301 		goto out;
302 	}
303 
304 	coda_dir_update_mtime(dir_inode);
305 	atomic_inc(&inode->i_count);
306 	d_instantiate(de, inode);
307 	inc_nlink(inode);
308 
309 out:
310 	unlock_kernel();
311 	return(error);
312 }
313 
314 
315 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
316 			const char *symname)
317 {
318         const char *name = de->d_name.name;
319 	int len = de->d_name.len;
320 	int symlen;
321 	int error = 0;
322 
323 	lock_kernel();
324 
325 	if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
326 		unlock_kernel();
327 		return -EPERM;
328 	}
329 
330 	symlen = strlen(symname);
331 	if ( symlen > CODA_MAXPATHLEN ) {
332 		unlock_kernel();
333 		return -ENAMETOOLONG;
334 	}
335 
336 	/*
337 	 * This entry is now negative. Since we do not create
338 	 * an inode for the entry we have to drop it.
339 	 */
340 	d_drop(de);
341 	error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
342 			      symname, symlen);
343 
344 	/* mtime is no good anymore */
345 	if ( !error )
346 		coda_dir_update_mtime(dir_inode);
347 
348 	unlock_kernel();
349 	return error;
350 }
351 
352 /* destruction routines: unlink, rmdir */
353 static int coda_unlink(struct inode *dir, struct dentry *de)
354 {
355         int error;
356 	const char *name = de->d_name.name;
357 	int len = de->d_name.len;
358 
359 	lock_kernel();
360 
361 	error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
362 	if ( error ) {
363 		unlock_kernel();
364 		return error;
365 	}
366 
367 	coda_dir_update_mtime(dir);
368 	drop_nlink(de->d_inode);
369 	unlock_kernel();
370 	return 0;
371 }
372 
373 static int coda_rmdir(struct inode *dir, struct dentry *de)
374 {
375 	const char *name = de->d_name.name;
376 	int len = de->d_name.len;
377 	int error;
378 
379 	lock_kernel();
380 
381 	error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
382 	if (!error) {
383 		/* VFS may delete the child */
384 		if (de->d_inode)
385 		    de->d_inode->i_nlink = 0;
386 
387 		/* fix the link count of the parent */
388 		coda_dir_drop_nlink(dir);
389 		coda_dir_update_mtime(dir);
390 	}
391 	unlock_kernel();
392 	return error;
393 }
394 
395 /* rename */
396 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
397 		       struct inode *new_dir, struct dentry *new_dentry)
398 {
399 	const char *old_name = old_dentry->d_name.name;
400 	const char *new_name = new_dentry->d_name.name;
401 	int old_length = old_dentry->d_name.len;
402 	int new_length = new_dentry->d_name.len;
403 	int error;
404 
405 	lock_kernel();
406 
407 	error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
408 			     coda_i2f(new_dir), old_length, new_length,
409 			     (const char *) old_name, (const char *)new_name);
410 
411 	if ( !error ) {
412 		if ( new_dentry->d_inode ) {
413 			if ( S_ISDIR(new_dentry->d_inode->i_mode) ) {
414 				coda_dir_drop_nlink(old_dir);
415 				coda_dir_inc_nlink(new_dir);
416 			}
417 			coda_dir_update_mtime(old_dir);
418 			coda_dir_update_mtime(new_dir);
419 			coda_flag_inode(new_dentry->d_inode, C_VATTR);
420 		} else {
421 			coda_flag_inode(old_dir, C_VATTR);
422 			coda_flag_inode(new_dir, C_VATTR);
423 		}
424 	}
425 	unlock_kernel();
426 
427 	return error;
428 }
429 
430 
431 /* file operations for directories */
432 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
433 {
434 	struct coda_file_info *cfi;
435 	struct file *host_file;
436 	int ret;
437 
438 	cfi = CODA_FTOC(coda_file);
439 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
440 	host_file = cfi->cfi_container;
441 
442 	if (!host_file->f_op)
443 		return -ENOTDIR;
444 
445 	if (host_file->f_op->readdir)
446 	{
447 		/* potemkin case: we were handed a directory inode.
448 		 * We can't use vfs_readdir because we have to keep the file
449 		 * position in sync between the coda_file and the host_file.
450 		 * and as such we need grab the inode mutex. */
451 		struct inode *host_inode = host_file->f_path.dentry->d_inode;
452 
453 		mutex_lock(&host_inode->i_mutex);
454 		host_file->f_pos = coda_file->f_pos;
455 
456 		ret = -ENOENT;
457 		if (!IS_DEADDIR(host_inode)) {
458 			ret = host_file->f_op->readdir(host_file, buf, filldir);
459 			file_accessed(host_file);
460 		}
461 
462 		coda_file->f_pos = host_file->f_pos;
463 		mutex_unlock(&host_inode->i_mutex);
464 	}
465 	else /* Venus: we must read Venus dirents from a file */
466 		ret = coda_venus_readdir(coda_file, buf, filldir);
467 
468 	return ret;
469 }
470 
471 static inline unsigned int CDT2DT(unsigned char cdt)
472 {
473 	unsigned int dt;
474 
475 	switch(cdt) {
476 	case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
477 	case CDT_FIFO:	  dt = DT_FIFO;    break;
478 	case CDT_CHR:	  dt = DT_CHR;     break;
479 	case CDT_DIR:	  dt = DT_DIR;     break;
480 	case CDT_BLK:	  dt = DT_BLK;     break;
481 	case CDT_REG:	  dt = DT_REG;     break;
482 	case CDT_LNK:	  dt = DT_LNK;     break;
483 	case CDT_SOCK:	  dt = DT_SOCK;    break;
484 	case CDT_WHT:	  dt = DT_WHT;     break;
485 	default:	  dt = DT_UNKNOWN; break;
486 	}
487 	return dt;
488 }
489 
490 /* support routines */
491 static int coda_venus_readdir(struct file *coda_file, void *buf,
492 			      filldir_t filldir)
493 {
494 	int result = 0; /* # of entries returned */
495 	struct coda_file_info *cfi;
496 	struct coda_inode_info *cii;
497 	struct file *host_file;
498 	struct dentry *de;
499 	struct venus_dirent *vdir;
500 	unsigned long vdir_size =
501 	    (unsigned long)(&((struct venus_dirent *)0)->d_name);
502 	unsigned int type;
503 	struct qstr name;
504 	ino_t ino;
505 	int ret;
506 
507 	cfi = CODA_FTOC(coda_file);
508 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
509 	host_file = cfi->cfi_container;
510 
511 	de = coda_file->f_path.dentry;
512 	cii = ITOC(de->d_inode);
513 
514 	vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
515 	if (!vdir) return -ENOMEM;
516 
517 	if (coda_file->f_pos == 0) {
518 		ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
519 		if (ret < 0)
520 			goto out;
521 		result++;
522 		coda_file->f_pos++;
523 	}
524 	if (coda_file->f_pos == 1) {
525 		ret = filldir(buf, "..", 2, 1, de->d_parent->d_inode->i_ino, DT_DIR);
526 		if (ret < 0)
527 			goto out;
528 		result++;
529 		coda_file->f_pos++;
530 	}
531 	while (1) {
532 		/* read entries from the directory file */
533 		ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
534 				  sizeof(*vdir));
535 		if (ret < 0) {
536 			printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
537 			       coda_f2s(&cii->c_fid), ret);
538 			break;
539 		}
540 		if (ret == 0) break; /* end of directory file reached */
541 
542 		/* catch truncated reads */
543 		if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
544 			printk(KERN_ERR "coda readdir: short read on %s\n",
545 			       coda_f2s(&cii->c_fid));
546 			ret = -EBADF;
547 			break;
548 		}
549 		/* validate whether the directory file actually makes sense */
550 		if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
551 			printk(KERN_ERR "coda readdir: invalid dir %s\n",
552 			       coda_f2s(&cii->c_fid));
553 			ret = -EBADF;
554 			break;
555 		}
556 
557 		name.len = vdir->d_namlen;
558 		name.name = vdir->d_name;
559 
560 		/* Make sure we skip '.' and '..', we already got those */
561 		if (name.name[0] == '.' && (name.len == 1 ||
562 		    (vdir->d_name[1] == '.' && name.len == 2)))
563 			vdir->d_fileno = name.len = 0;
564 
565 		/* skip null entries */
566 		if (vdir->d_fileno && name.len) {
567 			/* try to look up this entry in the dcache, that way
568 			 * userspace doesn't have to worry about breaking
569 			 * getcwd by having mismatched inode numbers for
570 			 * internal volume mountpoints. */
571 			ino = find_inode_number(de, &name);
572 			if (!ino) ino = vdir->d_fileno;
573 
574 			type = CDT2DT(vdir->d_type);
575 			ret = filldir(buf, name.name, name.len,
576 				      coda_file->f_pos, ino, type);
577 			/* failure means no space for filling in this round */
578 			if (ret < 0) break;
579 			result++;
580 		}
581 		/* we'll always have progress because d_reclen is unsigned and
582 		 * we've already established it is non-zero. */
583 		coda_file->f_pos += vdir->d_reclen;
584 	}
585 out:
586 	kfree(vdir);
587 	return result ? result : ret;
588 }
589 
590 /* called when a cache lookup succeeds */
591 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
592 {
593 	struct inode *inode = de->d_inode;
594 	struct coda_inode_info *cii;
595 
596 	if (!inode)
597 		return 1;
598 	lock_kernel();
599 	if (coda_isroot(inode))
600 		goto out;
601 	if (is_bad_inode(inode))
602 		goto bad;
603 
604 	cii = ITOC(de->d_inode);
605 	if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
606 		goto out;
607 
608 	shrink_dcache_parent(de);
609 
610 	/* propagate for a flush */
611 	if (cii->c_flags & C_FLUSH)
612 		coda_flag_inode_children(inode, C_FLUSH);
613 
614 	if (atomic_read(&de->d_count) > 1)
615 		/* pretend it's valid, but don't change the flags */
616 		goto out;
617 
618 	/* clear the flags. */
619 	cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
620 
621 bad:
622 	unlock_kernel();
623 	return 0;
624 out:
625 	unlock_kernel();
626 	return 1;
627 }
628 
629 /*
630  * This is the callback from dput() when d_count is going to 0.
631  * We use this to unhash dentries with bad inodes.
632  */
633 static int coda_dentry_delete(struct dentry * dentry)
634 {
635 	int flags;
636 
637 	if (!dentry->d_inode)
638 		return 0;
639 
640 	flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
641 	if (is_bad_inode(dentry->d_inode) || flags) {
642 		return 1;
643 	}
644 	return 0;
645 }
646 
647 
648 
649 /*
650  * This is called when we want to check if the inode has
651  * changed on the server.  Coda makes this easy since the
652  * cache manager Venus issues a downcall to the kernel when this
653  * happens
654  */
655 int coda_revalidate_inode(struct dentry *dentry)
656 {
657 	struct coda_vattr attr;
658 	int error = 0;
659 	int old_mode;
660 	ino_t old_ino;
661 	struct inode *inode = dentry->d_inode;
662 	struct coda_inode_info *cii = ITOC(inode);
663 
664 	lock_kernel();
665 	if ( !cii->c_flags )
666 		goto ok;
667 
668 	if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
669 		error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
670 		if ( error )
671 			goto return_bad;
672 
673 		/* this inode may be lost if:
674 		   - it's ino changed
675 		   - type changes must be permitted for repair and
676 		   missing mount points.
677 		*/
678 		old_mode = inode->i_mode;
679 		old_ino = inode->i_ino;
680 		coda_vattr_to_iattr(inode, &attr);
681 
682 		if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
683 			printk("Coda: inode %ld, fid %s changed type!\n",
684 			       inode->i_ino, coda_f2s(&(cii->c_fid)));
685 		}
686 
687 		/* the following can happen when a local fid is replaced
688 		   with a global one, here we lose and declare the inode bad */
689 		if (inode->i_ino != old_ino)
690 			goto return_bad;
691 
692 		coda_flag_inode_children(inode, C_FLUSH);
693 		cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
694 	}
695 
696 ok:
697 	unlock_kernel();
698 	return 0;
699 
700 return_bad:
701 	unlock_kernel();
702 	return -EIO;
703 }
704