xref: /openbmc/linux/fs/coda/dir.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 #include <linux/coda_proc.h>
29 
30 #include "coda_int.h"
31 
32 /* dir inode-ops */
33 static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
34 static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
35 static int coda_link(struct dentry *old_dentry, struct inode *dir_inode,
36 		     struct dentry *entry);
37 static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
38 static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
39 			const char *symname);
40 static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
41 static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
42 static int coda_rename(struct inode *old_inode, struct dentry *old_dentry,
43                        struct inode *new_inode, struct dentry *new_dentry);
44 
45 /* dir file-ops */
46 static int coda_readdir(struct file *file, void *dirent, filldir_t filldir);
47 
48 /* dentry ops */
49 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
50 static int coda_dentry_delete(struct dentry *);
51 
52 /* support routines */
53 static int coda_venus_readdir(struct file *filp, filldir_t filldir,
54 			      void *dirent, struct dentry *dir);
55 
56 /* same as fs/bad_inode.c */
57 static int coda_return_EIO(void)
58 {
59 	return -EIO;
60 }
61 #define CODA_EIO_ERROR ((void *) (coda_return_EIO))
62 
63 static struct dentry_operations coda_dentry_operations =
64 {
65 	.d_revalidate	= coda_dentry_revalidate,
66 	.d_delete	= coda_dentry_delete,
67 };
68 
69 const struct inode_operations coda_dir_inode_operations =
70 {
71 	.create		= coda_create,
72 	.lookup		= coda_lookup,
73 	.link		= coda_link,
74 	.unlink		= coda_unlink,
75 	.symlink	= coda_symlink,
76 	.mkdir		= coda_mkdir,
77 	.rmdir		= coda_rmdir,
78 	.mknod		= CODA_EIO_ERROR,
79 	.rename		= coda_rename,
80 	.permission	= coda_permission,
81 	.getattr	= coda_getattr,
82 	.setattr	= coda_setattr,
83 };
84 
85 const struct file_operations coda_dir_operations = {
86 	.llseek		= generic_file_llseek,
87 	.read		= generic_read_dir,
88 	.readdir	= coda_readdir,
89 	.open		= coda_open,
90 	.flush		= coda_flush,
91 	.release	= coda_release,
92 	.fsync		= coda_fsync,
93 };
94 
95 
96 /* inode operations for directories */
97 /* access routines: lookup, readlink, permission */
98 static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struct nameidata *nd)
99 {
100 	struct inode *res_inode = NULL;
101 	struct CodaFid resfid = { { 0, } };
102 	int dropme = 0; /* to indicate entry should not be cached */
103 	int type = 0;
104 	int error = 0;
105 	const char *name = entry->d_name.name;
106 	size_t length = entry->d_name.len;
107 
108 	if ( length > CODA_MAXNAMLEN ) {
109 	        printk("name too long: lookup, %s (%*s)\n",
110 		       coda_i2s(dir), (int)length, name);
111 		return ERR_PTR(-ENAMETOOLONG);
112 	}
113 
114 	lock_kernel();
115         /* control object, create inode on the fly */
116         if (coda_isroot(dir) && coda_iscontrol(name, length)) {
117 	        error = coda_cnode_makectl(&res_inode, dir->i_sb);
118 		dropme = 1;
119                 goto exit;
120         }
121 
122 	error = venus_lookup(dir->i_sb, coda_i2f(dir),
123 			     (const char *)name, length, &type, &resfid);
124 
125 	res_inode = NULL;
126 	if (!error) {
127 		if (type & CODA_NOCACHE) {
128 			type &= (~CODA_NOCACHE);
129 			dropme = 1;
130 		}
131 
132 	    	error = coda_cnode_make(&res_inode, &resfid, dir->i_sb);
133 		if (error) {
134 			unlock_kernel();
135 			return ERR_PTR(error);
136 		}
137 	} else if (error != -ENOENT) {
138 		unlock_kernel();
139 		return ERR_PTR(error);
140 	}
141 
142 exit:
143 	entry->d_time = 0;
144 	entry->d_op = &coda_dentry_operations;
145 	d_add(entry, res_inode);
146 	if ( dropme ) {
147 		d_drop(entry);
148 		coda_flag_inode(res_inode, C_VATTR);
149 	}
150 	unlock_kernel();
151         return NULL;
152 }
153 
154 
155 int coda_permission(struct inode *inode, int mask, struct nameidata *nd)
156 {
157         int error = 0;
158 
159 	if (!mask)
160 		return 0;
161 
162 	lock_kernel();
163 
164 	coda_vfs_stat.permission++;
165 
166 	if (coda_cache_check(inode, mask))
167 		goto out;
168 
169         error = venus_access(inode->i_sb, coda_i2f(inode), mask);
170 
171 	if (!error)
172 		coda_cache_enter(inode, mask);
173 
174  out:
175 	unlock_kernel();
176 
177         return error;
178 }
179 
180 
181 static inline void coda_dir_changed(struct inode *dir, int link)
182 {
183 #ifdef REQUERY_VENUS_FOR_MTIME
184 	/* invalidate the directory cnode's attributes so we refetch the
185 	 * attributes from venus next time the inode is referenced */
186 	coda_flag_inode(dir, C_VATTR);
187 #else
188 	/* optimistically we can also act as if our nose bleeds. The
189          * granularity of the mtime is coarse anyways so we might actually be
190          * right most of the time. Note: we only do this for directories. */
191 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
192 #endif
193 	if (link)
194 		dir->i_nlink += link;
195 }
196 
197 /* creation routines: create, mknod, mkdir, link, symlink */
198 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
199 {
200         int error=0;
201 	const char *name=de->d_name.name;
202 	int length=de->d_name.len;
203 	struct inode *inode;
204 	struct CodaFid newfid;
205 	struct coda_vattr attrs;
206 
207 	lock_kernel();
208 	coda_vfs_stat.create++;
209 
210 	if (coda_isroot(dir) && coda_iscontrol(name, length)) {
211 		unlock_kernel();
212 		return -EPERM;
213 	}
214 
215 	error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
216 				0, mode, &newfid, &attrs);
217 
218         if ( error ) {
219 		unlock_kernel();
220 		d_drop(de);
221 		return error;
222 	}
223 
224 	inode = coda_iget(dir->i_sb, &newfid, &attrs);
225 	if ( IS_ERR(inode) ) {
226 		unlock_kernel();
227 		d_drop(de);
228 		return PTR_ERR(inode);
229 	}
230 
231 	/* invalidate the directory cnode's attributes */
232 	coda_dir_changed(dir, 0);
233 	unlock_kernel();
234 	d_instantiate(de, inode);
235         return 0;
236 }
237 
238 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
239 {
240 	struct inode *inode;
241 	struct coda_vattr attrs;
242 	const char *name = de->d_name.name;
243 	int len = de->d_name.len;
244 	int error;
245 	struct CodaFid newfid;
246 
247 	lock_kernel();
248 	coda_vfs_stat.mkdir++;
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_changed(dir, 1);
274 	unlock_kernel();
275 	d_instantiate(de, inode);
276         return 0;
277 }
278 
279 /* try to make de an entry in dir_inodde linked to source_de */
280 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
281 	  struct dentry *de)
282 {
283 	struct inode *inode = source_de->d_inode;
284         const char * name = de->d_name.name;
285 	int len = de->d_name.len;
286 	int error;
287 
288 	lock_kernel();
289 	coda_vfs_stat.link++;
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_changed(dir_inode, 0);
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 	coda_vfs_stat.symlink++;
325 
326 	if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
327 		unlock_kernel();
328 		return -EPERM;
329 	}
330 
331 	symlen = strlen(symname);
332 	if ( symlen > CODA_MAXPATHLEN ) {
333 		unlock_kernel();
334 		return -ENAMETOOLONG;
335 	}
336 
337 	/*
338 	 * This entry is now negative. Since we do not create
339 	 * an inode for the entry we have to drop it.
340 	 */
341 	d_drop(de);
342 	error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
343 			      symname, symlen);
344 
345 	/* mtime is no good anymore */
346 	if ( !error )
347 		coda_dir_changed(dir_inode, 0);
348 
349 	unlock_kernel();
350         return error;
351 }
352 
353 /* destruction routines: unlink, rmdir */
354 int coda_unlink(struct inode *dir, struct dentry *de)
355 {
356         int error;
357 	const char *name = de->d_name.name;
358 	int len = de->d_name.len;
359 
360 	lock_kernel();
361 	coda_vfs_stat.unlink++;
362 
363         error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
364         if ( error ) {
365 		unlock_kernel();
366                 return error;
367         }
368 
369 	coda_dir_changed(dir, 0);
370 	drop_nlink(de->d_inode);
371 	unlock_kernel();
372 
373         return 0;
374 }
375 
376 int coda_rmdir(struct inode *dir, struct dentry *de)
377 {
378 	const char *name = de->d_name.name;
379 	int len = de->d_name.len;
380         int error;
381 
382 	lock_kernel();
383 	coda_vfs_stat.rmdir++;
384 
385 	if (!d_unhashed(de)) {
386 		unlock_kernel();
387 		return -EBUSY;
388 	}
389 	error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
390 
391         if ( error ) {
392 		unlock_kernel();
393                 return error;
394         }
395 
396 	coda_dir_changed(dir, -1);
397 	drop_nlink(de->d_inode);
398 	d_delete(de);
399 	unlock_kernel();
400 
401         return 0;
402 }
403 
404 /* rename */
405 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
406 		       struct inode *new_dir, struct dentry *new_dentry)
407 {
408         const char *old_name = old_dentry->d_name.name;
409         const char *new_name = new_dentry->d_name.name;
410 	int old_length = old_dentry->d_name.len;
411 	int new_length = new_dentry->d_name.len;
412         int link_adjust = 0;
413         int error;
414 
415 	lock_kernel();
416 	coda_vfs_stat.rename++;
417 
418         error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
419 			     coda_i2f(new_dir), old_length, new_length,
420 			     (const char *) old_name, (const char *)new_name);
421 
422         if ( !error ) {
423 		if ( new_dentry->d_inode ) {
424 			if ( S_ISDIR(new_dentry->d_inode->i_mode) )
425                         	link_adjust = 1;
426 
427                         coda_dir_changed(old_dir, -link_adjust);
428                         coda_dir_changed(new_dir,  link_adjust);
429 			coda_flag_inode(new_dentry->d_inode, C_VATTR);
430 		} else {
431 			coda_flag_inode(old_dir, C_VATTR);
432 			coda_flag_inode(new_dir, C_VATTR);
433                 }
434 	}
435 	unlock_kernel();
436 
437 	return error;
438 }
439 
440 
441 /* file operations for directories */
442 int coda_readdir(struct file *coda_file, void *dirent, filldir_t filldir)
443 {
444 	struct dentry *coda_dentry = coda_file->f_path.dentry;
445 	struct coda_file_info *cfi;
446 	struct file *host_file;
447 	struct inode *host_inode;
448 	int ret;
449 
450 	cfi = CODA_FTOC(coda_file);
451 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
452 	host_file = cfi->cfi_container;
453 
454 	coda_vfs_stat.readdir++;
455 
456 	host_inode = host_file->f_path.dentry->d_inode;
457 	mutex_lock(&host_inode->i_mutex);
458 	host_file->f_pos = coda_file->f_pos;
459 
460 	if (!host_file->f_op->readdir) {
461 		/* Venus: we must read Venus dirents from the file */
462 		ret = coda_venus_readdir(host_file, filldir, dirent, coda_dentry);
463 	} else {
464 		/* potemkin case: we were handed a directory inode. */
465 		/* Yuk, we can't call vfs_readdir because we are already
466 		 * holding the inode semaphore. */
467 		ret = -ENOTDIR;
468 		if (!host_file->f_op || !host_file->f_op->readdir)
469 			goto out;
470 
471 		ret = -ENOENT;
472 		if (!IS_DEADDIR(host_inode)) {
473 			ret = host_file->f_op->readdir(host_file, filldir, dirent);
474 			file_accessed(host_file);
475 		}
476 	}
477 out:
478 	coda_file->f_pos = host_file->f_pos;
479 	mutex_unlock(&host_inode->i_mutex);
480 
481 	return ret;
482 }
483 
484 static inline unsigned int CDT2DT(unsigned char cdt)
485 {
486 	unsigned int dt;
487 
488 	switch(cdt) {
489 	case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
490 	case CDT_FIFO:	  dt = DT_FIFO;    break;
491 	case CDT_CHR:	  dt = DT_CHR;     break;
492 	case CDT_DIR:	  dt = DT_DIR;     break;
493 	case CDT_BLK:	  dt = DT_BLK;     break;
494 	case CDT_REG:	  dt = DT_REG;     break;
495 	case CDT_LNK:	  dt = DT_LNK;     break;
496 	case CDT_SOCK:	  dt = DT_SOCK;    break;
497 	case CDT_WHT:	  dt = DT_WHT;     break;
498 	default:	  dt = DT_UNKNOWN; break;
499 	}
500 	return dt;
501 }
502 
503 /* support routines */
504 static int coda_venus_readdir(struct file *filp, filldir_t filldir,
505 			      void *dirent, struct dentry *dir)
506 {
507 	int result = 0; /* # of entries returned */
508 	struct venus_dirent *vdir;
509 	unsigned long vdir_size =
510 	    (unsigned long)(&((struct venus_dirent *)0)->d_name);
511 	unsigned int type;
512 	struct qstr name;
513 	ino_t ino;
514 	int ret, i;
515 
516 	vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
517 	if (!vdir) return -ENOMEM;
518 
519 	i = filp->f_pos;
520 	switch(i) {
521 	case 0:
522 		ret = filldir(dirent, ".", 1, 0, dir->d_inode->i_ino, DT_DIR);
523 		if (ret < 0) break;
524 		result++;
525 		filp->f_pos++;
526 		/* fallthrough */
527 	case 1:
528 		ret = filldir(dirent, "..", 2, 1, dir->d_parent->d_inode->i_ino, DT_DIR);
529 		if (ret < 0) break;
530 		result++;
531 		filp->f_pos++;
532 		/* fallthrough */
533 	default:
534 	while (1) {
535 		/* read entries from the directory file */
536 		ret = kernel_read(filp, filp->f_pos - 2, (char *)vdir,
537 				  sizeof(*vdir));
538 		if (ret < 0) {
539 			printk("coda_venus_readdir: read dir failed %d\n", ret);
540 			break;
541 		}
542 		if (ret == 0) break; /* end of directory file reached */
543 
544 		/* catch truncated reads */
545 		if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
546 			printk("coda_venus_readdir: short read: %ld\n",
547 			       filp->f_path.dentry->d_inode->i_ino);
548 			ret = -EBADF;
549 			break;
550 		}
551 		/* validate whether the directory file actually makes sense */
552 		if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
553 			printk("coda_venus_readdir: Invalid dir: %ld\n",
554 			       filp->f_path.dentry->d_inode->i_ino);
555 			ret = -EBADF;
556 			break;
557 		}
558 
559 		name.len = vdir->d_namlen;
560 		name.name = vdir->d_name;
561 
562 		/* Make sure we skip '.' and '..', we already got those */
563 		if (name.name[0] == '.' && (name.len == 1 ||
564 		    (vdir->d_name[1] == '.' && name.len == 2)))
565 			vdir->d_fileno = name.len = 0;
566 
567 		/* skip null entries */
568 		if (vdir->d_fileno && name.len) {
569 			/* try to look up this entry in the dcache, that way
570 			 * userspace doesn't have to worry about breaking
571 			 * getcwd by having mismatched inode numbers for
572 			 * internal volume mountpoints. */
573 			ino = find_inode_number(dir, &name);
574 			if (!ino) ino = vdir->d_fileno;
575 
576 			type = CDT2DT(vdir->d_type);
577 			ret = filldir(dirent, name.name, name.len, filp->f_pos,
578 				      ino, type);
579 			/* failure means no space for filling in this round */
580 			if (ret < 0) break;
581 			result++;
582 		}
583 		/* we'll always have progress because d_reclen is unsigned and
584 		 * we've already established it is non-zero. */
585 		filp->f_pos += vdir->d_reclen;
586 	}
587 	}
588 	kfree(vdir);
589 	return result ? result : ret;
590 }
591 
592 /* called when a cache lookup succeeds */
593 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
594 {
595 	struct inode *inode = de->d_inode;
596 	struct coda_inode_info *cii;
597 
598 	if (!inode)
599 		return 1;
600 	lock_kernel();
601 	if (coda_isroot(inode))
602 		goto out;
603 	if (is_bad_inode(inode))
604 		goto bad;
605 
606 	cii = ITOC(de->d_inode);
607 	if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
608 		goto out;
609 
610 	shrink_dcache_parent(de);
611 
612 	/* propagate for a flush */
613 	if (cii->c_flags & C_FLUSH)
614 		coda_flag_inode_children(inode, C_FLUSH);
615 
616 	if (atomic_read(&de->d_count) > 1)
617 		/* pretend it's valid, but don't change the flags */
618 		goto out;
619 
620 	/* clear the flags. */
621 	cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
622 
623 bad:
624 	unlock_kernel();
625 	return 0;
626 out:
627 	unlock_kernel();
628 	return 1;
629 }
630 
631 /*
632  * This is the callback from dput() when d_count is going to 0.
633  * We use this to unhash dentries with bad inodes.
634  */
635 static int coda_dentry_delete(struct dentry * dentry)
636 {
637 	int flags;
638 
639 	if (!dentry->d_inode)
640 		return 0;
641 
642 	flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
643 	if (is_bad_inode(dentry->d_inode) || flags) {
644 		return 1;
645 	}
646 	return 0;
647 }
648 
649 
650 
651 /*
652  * This is called when we want to check if the inode has
653  * changed on the server.  Coda makes this easy since the
654  * cache manager Venus issues a downcall to the kernel when this
655  * happens
656  */
657 int coda_revalidate_inode(struct dentry *dentry)
658 {
659 	struct coda_vattr attr;
660 	int error = 0;
661 	int old_mode;
662 	ino_t old_ino;
663 	struct inode *inode = dentry->d_inode;
664 	struct coda_inode_info *cii = ITOC(inode);
665 
666 	lock_kernel();
667 	if ( !cii->c_flags )
668 		goto ok;
669 
670 	if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
671 		error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
672 		if ( error )
673 			goto return_bad;
674 
675 		/* this inode may be lost if:
676 		   - it's ino changed
677 		   - type changes must be permitted for repair and
678 		   missing mount points.
679 		*/
680 		old_mode = inode->i_mode;
681 		old_ino = inode->i_ino;
682 		coda_vattr_to_iattr(inode, &attr);
683 
684 		if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
685 			printk("Coda: inode %ld, fid %s changed type!\n",
686 			       inode->i_ino, coda_f2s(&(cii->c_fid)));
687 		}
688 
689 		/* the following can happen when a local fid is replaced
690 		   with a global one, here we lose and declare the inode bad */
691 		if (inode->i_ino != old_ino)
692 			goto return_bad;
693 
694 		coda_flag_inode_children(inode, C_FLUSH);
695 		cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
696 	}
697 
698 ok:
699 	unlock_kernel();
700 	return 0;
701 
702 return_bad:
703 	unlock_kernel();
704 	return -EIO;
705 }
706