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 */
33static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
34static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
35static int coda_link(struct dentry *old_dentry, struct inode *dir_inode,
36		     struct dentry *entry);
37static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
38static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
39			const char *symname);
40static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
41static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
42static 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 */
46static int coda_readdir(struct file *file, void *dirent, filldir_t filldir);
47
48/* dentry ops */
49static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
50static int coda_dentry_delete(struct dentry *);
51
52/* support routines */
53static int coda_venus_readdir(struct file *filp, filldir_t filldir,
54			      void *dirent, struct dentry *dir);
55
56/* same as fs/bad_inode.c */
57static int coda_return_EIO(void)
58{
59	return -EIO;
60}
61#define CODA_EIO_ERROR ((void *) (coda_return_EIO))
62
63static struct dentry_operations coda_dentry_operations =
64{
65	.d_revalidate	= coda_dentry_revalidate,
66	.d_delete	= coda_dentry_delete,
67};
68
69const 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
85const 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 */
98static 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
142exit:
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
155int 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
181static 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 */
198static 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
238static 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 */
280static 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
309out:
310	unlock_kernel();
311	return(error);
312}
313
314
315static 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 */
354int 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
376int 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 */
405static 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 */
442int 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	}
477out:
478	coda_file->f_pos = host_file->f_pos;
479	mutex_unlock(&host_inode->i_mutex);
480
481	return ret;
482}
483
484static 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 */
504static 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 */
593static 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
623bad:
624	unlock_kernel();
625	return 0;
626out:
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 */
635static 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 */
657int 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
698ok:
699	unlock_kernel();
700	return 0;
701
702return_bad:
703	unlock_kernel();
704	return -EIO;
705}
706