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/slab.h>
16#include <linux/file.h>
17#include <linux/stat.h>
18#include <linux/errno.h>
19#include <linux/string.h>
20#include <linux/spinlock.h>
21#include <linux/namei.h>
22#include <linux/uaccess.h>
23
24#include <linux/coda.h>
25#include <linux/coda_psdev.h>
26#include "coda_linux.h"
27#include "coda_cache.h"
28
29#include "coda_int.h"
30
31/* same as fs/bad_inode.c */
32static int coda_return_EIO(void)
33{
34	return -EIO;
35}
36#define CODA_EIO_ERROR ((void *) (coda_return_EIO))
37
38/* inode operations for directories */
39/* access routines: lookup, readlink, permission */
40static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, unsigned int flags)
41{
42	struct super_block *sb = dir->i_sb;
43	const char *name = entry->d_name.name;
44	size_t length = entry->d_name.len;
45	struct inode *inode;
46	int type = 0;
47
48	if (length > CODA_MAXNAMLEN) {
49		pr_err("name too long: lookup, %s (%*s)\n",
50		       coda_i2s(dir), (int)length, name);
51		return ERR_PTR(-ENAMETOOLONG);
52	}
53
54	/* control object, create inode on the fly */
55	if (is_root_inode(dir) && coda_iscontrol(name, length)) {
56		inode = coda_cnode_makectl(sb);
57		type = CODA_NOCACHE;
58	} else {
59		struct CodaFid fid = { { 0, } };
60		int error = venus_lookup(sb, coda_i2f(dir), name, length,
61				     &type, &fid);
62		inode = !error ? coda_cnode_make(&fid, sb) : ERR_PTR(error);
63	}
64
65	if (!IS_ERR(inode) && (type & CODA_NOCACHE))
66		coda_flag_inode(inode, C_VATTR | C_PURGE);
67
68	if (inode == ERR_PTR(-ENOENT))
69		inode = NULL;
70
71	return d_splice_alias(inode, entry);
72}
73
74
75int coda_permission(struct inode *inode, int mask)
76{
77	int error;
78
79	if (mask & MAY_NOT_BLOCK)
80		return -ECHILD;
81
82	mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
83
84	if (!mask)
85		return 0;
86
87	if ((mask & MAY_EXEC) && !execute_ok(inode))
88		return -EACCES;
89
90	if (coda_cache_check(inode, mask))
91		return 0;
92
93	error = venus_access(inode->i_sb, coda_i2f(inode), mask);
94
95	if (!error)
96		coda_cache_enter(inode, mask);
97
98	return error;
99}
100
101
102static inline void coda_dir_update_mtime(struct inode *dir)
103{
104#ifdef REQUERY_VENUS_FOR_MTIME
105	/* invalidate the directory cnode's attributes so we refetch the
106	 * attributes from venus next time the inode is referenced */
107	coda_flag_inode(dir, C_VATTR);
108#else
109	/* optimistically we can also act as if our nose bleeds. The
110	 * granularity of the mtime is coarse anyways so we might actually be
111	 * right most of the time. Note: we only do this for directories. */
112	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
113#endif
114}
115
116/* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
117 * trick to fool GNU find's optimizations. If we can't be sure of the link
118 * (because of volume mount points) we set i_nlink to 1 which forces find
119 * to consider every child as a possible directory. We should also never
120 * see an increment or decrement for deleted directories where i_nlink == 0 */
121static inline void coda_dir_inc_nlink(struct inode *dir)
122{
123	if (dir->i_nlink >= 2)
124		inc_nlink(dir);
125}
126
127static inline void coda_dir_drop_nlink(struct inode *dir)
128{
129	if (dir->i_nlink > 2)
130		drop_nlink(dir);
131}
132
133/* creation routines: create, mknod, mkdir, link, symlink */
134static int coda_create(struct inode *dir, struct dentry *de, umode_t mode, bool excl)
135{
136	int error;
137	const char *name=de->d_name.name;
138	int length=de->d_name.len;
139	struct inode *inode;
140	struct CodaFid newfid;
141	struct coda_vattr attrs;
142
143	if (is_root_inode(dir) && coda_iscontrol(name, length))
144		return -EPERM;
145
146	error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
147				0, mode, &newfid, &attrs);
148	if (error)
149		goto err_out;
150
151	inode = coda_iget(dir->i_sb, &newfid, &attrs);
152	if (IS_ERR(inode)) {
153		error = PTR_ERR(inode);
154		goto err_out;
155	}
156
157	/* invalidate the directory cnode's attributes */
158	coda_dir_update_mtime(dir);
159	d_instantiate(de, inode);
160	return 0;
161err_out:
162	d_drop(de);
163	return error;
164}
165
166static int coda_mkdir(struct inode *dir, struct dentry *de, umode_t mode)
167{
168	struct inode *inode;
169	struct coda_vattr attrs;
170	const char *name = de->d_name.name;
171	int len = de->d_name.len;
172	int error;
173	struct CodaFid newfid;
174
175	if (is_root_inode(dir) && coda_iscontrol(name, len))
176		return -EPERM;
177
178	attrs.va_mode = mode;
179	error = venus_mkdir(dir->i_sb, coda_i2f(dir),
180			       name, len, &newfid, &attrs);
181	if (error)
182		goto err_out;
183
184	inode = coda_iget(dir->i_sb, &newfid, &attrs);
185	if (IS_ERR(inode)) {
186		error = PTR_ERR(inode);
187		goto err_out;
188	}
189
190	/* invalidate the directory cnode's attributes */
191	coda_dir_inc_nlink(dir);
192	coda_dir_update_mtime(dir);
193	d_instantiate(de, inode);
194	return 0;
195err_out:
196	d_drop(de);
197	return error;
198}
199
200/* try to make de an entry in dir_inodde linked to source_de */
201static int coda_link(struct dentry *source_de, struct inode *dir_inode,
202	  struct dentry *de)
203{
204	struct inode *inode = d_inode(source_de);
205        const char * name = de->d_name.name;
206	int len = de->d_name.len;
207	int error;
208
209	if (is_root_inode(dir_inode) && coda_iscontrol(name, len))
210		return -EPERM;
211
212	error = venus_link(dir_inode->i_sb, coda_i2f(inode),
213			   coda_i2f(dir_inode), (const char *)name, len);
214	if (error) {
215		d_drop(de);
216		return error;
217	}
218
219	coda_dir_update_mtime(dir_inode);
220	ihold(inode);
221	d_instantiate(de, inode);
222	inc_nlink(inode);
223	return 0;
224}
225
226
227static int coda_symlink(struct inode *dir_inode, struct dentry *de,
228			const char *symname)
229{
230	const char *name = de->d_name.name;
231	int len = de->d_name.len;
232	int symlen;
233	int error;
234
235	if (is_root_inode(dir_inode) && coda_iscontrol(name, len))
236		return -EPERM;
237
238	symlen = strlen(symname);
239	if (symlen > CODA_MAXPATHLEN)
240		return -ENAMETOOLONG;
241
242	/*
243	 * This entry is now negative. Since we do not create
244	 * an inode for the entry we have to drop it.
245	 */
246	d_drop(de);
247	error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
248			      symname, symlen);
249
250	/* mtime is no good anymore */
251	if (!error)
252		coda_dir_update_mtime(dir_inode);
253
254	return error;
255}
256
257/* destruction routines: unlink, rmdir */
258static int coda_unlink(struct inode *dir, struct dentry *de)
259{
260        int error;
261	const char *name = de->d_name.name;
262	int len = de->d_name.len;
263
264	error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
265	if (error)
266		return error;
267
268	coda_dir_update_mtime(dir);
269	drop_nlink(d_inode(de));
270	return 0;
271}
272
273static int coda_rmdir(struct inode *dir, struct dentry *de)
274{
275	const char *name = de->d_name.name;
276	int len = de->d_name.len;
277	int error;
278
279	error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
280	if (!error) {
281		/* VFS may delete the child */
282		if (d_really_is_positive(de))
283			clear_nlink(d_inode(de));
284
285		/* fix the link count of the parent */
286		coda_dir_drop_nlink(dir);
287		coda_dir_update_mtime(dir);
288	}
289	return error;
290}
291
292/* rename */
293static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
294		       struct inode *new_dir, struct dentry *new_dentry)
295{
296	const char *old_name = old_dentry->d_name.name;
297	const char *new_name = new_dentry->d_name.name;
298	int old_length = old_dentry->d_name.len;
299	int new_length = new_dentry->d_name.len;
300	int error;
301
302	error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
303			     coda_i2f(new_dir), old_length, new_length,
304			     (const char *) old_name, (const char *)new_name);
305	if (!error) {
306		if (d_really_is_positive(new_dentry)) {
307			if (d_is_dir(new_dentry)) {
308				coda_dir_drop_nlink(old_dir);
309				coda_dir_inc_nlink(new_dir);
310			}
311			coda_dir_update_mtime(old_dir);
312			coda_dir_update_mtime(new_dir);
313			coda_flag_inode(d_inode(new_dentry), C_VATTR);
314		} else {
315			coda_flag_inode(old_dir, C_VATTR);
316			coda_flag_inode(new_dir, C_VATTR);
317		}
318	}
319	return error;
320}
321
322static inline unsigned int CDT2DT(unsigned char cdt)
323{
324	unsigned int dt;
325
326	switch(cdt) {
327	case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
328	case CDT_FIFO:	  dt = DT_FIFO;    break;
329	case CDT_CHR:	  dt = DT_CHR;     break;
330	case CDT_DIR:	  dt = DT_DIR;     break;
331	case CDT_BLK:	  dt = DT_BLK;     break;
332	case CDT_REG:	  dt = DT_REG;     break;
333	case CDT_LNK:	  dt = DT_LNK;     break;
334	case CDT_SOCK:	  dt = DT_SOCK;    break;
335	case CDT_WHT:	  dt = DT_WHT;     break;
336	default:	  dt = DT_UNKNOWN; break;
337	}
338	return dt;
339}
340
341/* support routines */
342static int coda_venus_readdir(struct file *coda_file, struct dir_context *ctx)
343{
344	struct coda_file_info *cfi;
345	struct coda_inode_info *cii;
346	struct file *host_file;
347	struct venus_dirent *vdir;
348	unsigned long vdir_size = offsetof(struct venus_dirent, d_name);
349	unsigned int type;
350	struct qstr name;
351	ino_t ino;
352	int ret;
353
354	cfi = CODA_FTOC(coda_file);
355	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
356	host_file = cfi->cfi_container;
357
358	cii = ITOC(file_inode(coda_file));
359
360	vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
361	if (!vdir) return -ENOMEM;
362
363	if (!dir_emit_dots(coda_file, ctx))
364		goto out;
365
366	while (1) {
367		/* read entries from the directory file */
368		ret = kernel_read(host_file, ctx->pos - 2, (char *)vdir,
369				  sizeof(*vdir));
370		if (ret < 0) {
371			pr_err("%s: read dir %s failed %d\n",
372			       __func__, coda_f2s(&cii->c_fid), ret);
373			break;
374		}
375		if (ret == 0) break; /* end of directory file reached */
376
377		/* catch truncated reads */
378		if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
379			pr_err("%s: short read on %s\n",
380			       __func__, coda_f2s(&cii->c_fid));
381			ret = -EBADF;
382			break;
383		}
384		/* validate whether the directory file actually makes sense */
385		if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
386			pr_err("%s: invalid dir %s\n",
387			       __func__, coda_f2s(&cii->c_fid));
388			ret = -EBADF;
389			break;
390		}
391
392		name.len = vdir->d_namlen;
393		name.name = vdir->d_name;
394
395		/* Make sure we skip '.' and '..', we already got those */
396		if (name.name[0] == '.' && (name.len == 1 ||
397		    (name.name[1] == '.' && name.len == 2)))
398			vdir->d_fileno = name.len = 0;
399
400		/* skip null entries */
401		if (vdir->d_fileno && name.len) {
402			ino = vdir->d_fileno;
403			type = CDT2DT(vdir->d_type);
404			if (!dir_emit(ctx, name.name, name.len, ino, type))
405				break;
406		}
407		/* we'll always have progress because d_reclen is unsigned and
408		 * we've already established it is non-zero. */
409		ctx->pos += vdir->d_reclen;
410	}
411out:
412	kfree(vdir);
413	return 0;
414}
415
416/* file operations for directories */
417static int coda_readdir(struct file *coda_file, struct dir_context *ctx)
418{
419	struct coda_file_info *cfi;
420	struct file *host_file;
421	int ret;
422
423	cfi = CODA_FTOC(coda_file);
424	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
425	host_file = cfi->cfi_container;
426
427	if (host_file->f_op->iterate) {
428		struct inode *host_inode = file_inode(host_file);
429
430		mutex_lock(&host_inode->i_mutex);
431		ret = -ENOENT;
432		if (!IS_DEADDIR(host_inode)) {
433			ret = host_file->f_op->iterate(host_file, ctx);
434			file_accessed(host_file);
435		}
436		mutex_unlock(&host_inode->i_mutex);
437		return ret;
438	}
439	/* Venus: we must read Venus dirents from a file */
440	return coda_venus_readdir(coda_file, ctx);
441}
442
443/* called when a cache lookup succeeds */
444static int coda_dentry_revalidate(struct dentry *de, unsigned int flags)
445{
446	struct inode *inode;
447	struct coda_inode_info *cii;
448
449	if (flags & LOOKUP_RCU)
450		return -ECHILD;
451
452	inode = d_inode(de);
453	if (!inode || is_root_inode(inode))
454		goto out;
455	if (is_bad_inode(inode))
456		goto bad;
457
458	cii = ITOC(d_inode(de));
459	if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
460		goto out;
461
462	shrink_dcache_parent(de);
463
464	/* propagate for a flush */
465	if (cii->c_flags & C_FLUSH)
466		coda_flag_inode_children(inode, C_FLUSH);
467
468	if (d_count(de) > 1)
469		/* pretend it's valid, but don't change the flags */
470		goto out;
471
472	/* clear the flags. */
473	spin_lock(&cii->c_lock);
474	cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
475	spin_unlock(&cii->c_lock);
476bad:
477	return 0;
478out:
479	return 1;
480}
481
482/*
483 * This is the callback from dput() when d_count is going to 0.
484 * We use this to unhash dentries with bad inodes.
485 */
486static int coda_dentry_delete(const struct dentry * dentry)
487{
488	int flags;
489
490	if (d_really_is_negative(dentry))
491		return 0;
492
493	flags = (ITOC(d_inode(dentry))->c_flags) & C_PURGE;
494	if (is_bad_inode(d_inode(dentry)) || flags) {
495		return 1;
496	}
497	return 0;
498}
499
500
501
502/*
503 * This is called when we want to check if the inode has
504 * changed on the server.  Coda makes this easy since the
505 * cache manager Venus issues a downcall to the kernel when this
506 * happens
507 */
508int coda_revalidate_inode(struct inode *inode)
509{
510	struct coda_vattr attr;
511	int error;
512	int old_mode;
513	ino_t old_ino;
514	struct coda_inode_info *cii = ITOC(inode);
515
516	if (!cii->c_flags)
517		return 0;
518
519	if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
520		error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
521		if (error)
522			return -EIO;
523
524		/* this inode may be lost if:
525		   - it's ino changed
526		   - type changes must be permitted for repair and
527		   missing mount points.
528		*/
529		old_mode = inode->i_mode;
530		old_ino = inode->i_ino;
531		coda_vattr_to_iattr(inode, &attr);
532
533		if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
534			pr_warn("inode %ld, fid %s changed type!\n",
535				inode->i_ino, coda_f2s(&(cii->c_fid)));
536		}
537
538		/* the following can happen when a local fid is replaced
539		   with a global one, here we lose and declare the inode bad */
540		if (inode->i_ino != old_ino)
541			return -EIO;
542
543		coda_flag_inode_children(inode, C_FLUSH);
544
545		spin_lock(&cii->c_lock);
546		cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
547		spin_unlock(&cii->c_lock);
548	}
549	return 0;
550}
551
552const struct dentry_operations coda_dentry_operations = {
553	.d_revalidate	= coda_dentry_revalidate,
554	.d_delete	= coda_dentry_delete,
555};
556
557const struct inode_operations coda_dir_inode_operations = {
558	.create		= coda_create,
559	.lookup		= coda_lookup,
560	.link		= coda_link,
561	.unlink		= coda_unlink,
562	.symlink	= coda_symlink,
563	.mkdir		= coda_mkdir,
564	.rmdir		= coda_rmdir,
565	.mknod		= CODA_EIO_ERROR,
566	.rename		= coda_rename,
567	.permission	= coda_permission,
568	.getattr	= coda_getattr,
569	.setattr	= coda_setattr,
570};
571
572const struct file_operations coda_dir_operations = {
573	.llseek		= generic_file_llseek,
574	.read		= generic_read_dir,
575	.iterate	= coda_readdir,
576	.open		= coda_open,
577	.release	= coda_release,
578	.fsync		= coda_fsync,
579};
580