1 /*
2  * SPU file system
3  *
4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
5  *
6  * Author: Arnd Bergmann <arndb@de.ibm.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2, or (at your option)
11  * any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21  */
22 
23 #include <linux/file.h>
24 #include <linux/fs.h>
25 #include <linux/backing-dev.h>
26 #include <linux/init.h>
27 #include <linux/ioctl.h>
28 #include <linux/module.h>
29 #include <linux/mount.h>
30 #include <linux/namei.h>
31 #include <linux/pagemap.h>
32 #include <linux/poll.h>
33 #include <linux/slab.h>
34 #include <linux/parser.h>
35 
36 #include <asm/io.h>
37 #include <asm/semaphore.h>
38 #include <asm/spu.h>
39 #include <asm/uaccess.h>
40 
41 #include "spufs.h"
42 
43 static kmem_cache_t *spufs_inode_cache;
44 
45 static struct inode *
46 spufs_alloc_inode(struct super_block *sb)
47 {
48 	struct spufs_inode_info *ei;
49 
50 	ei = kmem_cache_alloc(spufs_inode_cache, SLAB_KERNEL);
51 	if (!ei)
52 		return NULL;
53 	return &ei->vfs_inode;
54 }
55 
56 static void
57 spufs_destroy_inode(struct inode *inode)
58 {
59 	kmem_cache_free(spufs_inode_cache, SPUFS_I(inode));
60 }
61 
62 static void
63 spufs_init_once(void *p, kmem_cache_t * cachep, unsigned long flags)
64 {
65 	struct spufs_inode_info *ei = p;
66 
67 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
68 	    SLAB_CTOR_CONSTRUCTOR) {
69 		inode_init_once(&ei->vfs_inode);
70 	}
71 }
72 
73 static struct inode *
74 spufs_new_inode(struct super_block *sb, int mode)
75 {
76 	struct inode *inode;
77 
78 	inode = new_inode(sb);
79 	if (!inode)
80 		goto out;
81 
82 	inode->i_mode = mode;
83 	inode->i_uid = current->fsuid;
84 	inode->i_gid = current->fsgid;
85 	inode->i_blksize = PAGE_CACHE_SIZE;
86 	inode->i_blocks = 0;
87 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
88 out:
89 	return inode;
90 }
91 
92 static int
93 spufs_setattr(struct dentry *dentry, struct iattr *attr)
94 {
95 	struct inode *inode = dentry->d_inode;
96 
97 	if ((attr->ia_valid & ATTR_SIZE) &&
98 	    (attr->ia_size != inode->i_size))
99 		return -EINVAL;
100 	return inode_setattr(inode, attr);
101 }
102 
103 
104 static int
105 spufs_new_file(struct super_block *sb, struct dentry *dentry,
106 		struct file_operations *fops, int mode,
107 		struct spu_context *ctx)
108 {
109 	static struct inode_operations spufs_file_iops = {
110 		.setattr = spufs_setattr,
111 	};
112 	struct inode *inode;
113 	int ret;
114 
115 	ret = -ENOSPC;
116 	inode = spufs_new_inode(sb, S_IFREG | mode);
117 	if (!inode)
118 		goto out;
119 
120 	ret = 0;
121 	inode->i_op = &spufs_file_iops;
122 	inode->i_fop = fops;
123 	inode->u.generic_ip = SPUFS_I(inode)->i_ctx = get_spu_context(ctx);
124 	d_add(dentry, inode);
125 out:
126 	return ret;
127 }
128 
129 static void
130 spufs_delete_inode(struct inode *inode)
131 {
132 	if (SPUFS_I(inode)->i_ctx)
133 		put_spu_context(SPUFS_I(inode)->i_ctx);
134 	clear_inode(inode);
135 }
136 
137 static void spufs_prune_dir(struct dentry *dir)
138 {
139 	struct dentry *dentry, *tmp;
140 	mutex_lock(&dir->d_inode->i_mutex);
141 	list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) {
142 		spin_lock(&dcache_lock);
143 		spin_lock(&dentry->d_lock);
144 		if (!(d_unhashed(dentry)) && dentry->d_inode) {
145 			dget_locked(dentry);
146 			__d_drop(dentry);
147 			spin_unlock(&dentry->d_lock);
148 			simple_unlink(dir->d_inode, dentry);
149 			spin_unlock(&dcache_lock);
150 			dput(dentry);
151 		} else {
152 			spin_unlock(&dentry->d_lock);
153 			spin_unlock(&dcache_lock);
154 		}
155 	}
156 	shrink_dcache_parent(dir);
157 	mutex_unlock(&dir->d_inode->i_mutex);
158 }
159 
160 static int spufs_rmdir(struct inode *root, struct dentry *dir_dentry)
161 {
162 	struct spu_context *ctx;
163 
164 	/* remove all entries */
165 	mutex_lock(&root->i_mutex);
166 	spufs_prune_dir(dir_dentry);
167 	mutex_unlock(&root->i_mutex);
168 
169 	/* We have to give up the mm_struct */
170 	ctx = SPUFS_I(dir_dentry->d_inode)->i_ctx;
171 	spu_forget(ctx);
172 
173 	/* XXX Do we need to hold i_mutex here ? */
174 	return simple_rmdir(root, dir_dentry);
175 }
176 
177 static int spufs_fill_dir(struct dentry *dir, struct tree_descr *files,
178 			  int mode, struct spu_context *ctx)
179 {
180 	struct dentry *dentry;
181 	int ret;
182 
183 	while (files->name && files->name[0]) {
184 		ret = -ENOMEM;
185 		dentry = d_alloc_name(dir, files->name);
186 		if (!dentry)
187 			goto out;
188 		ret = spufs_new_file(dir->d_sb, dentry, files->ops,
189 					files->mode & mode, ctx);
190 		if (ret)
191 			goto out;
192 		files++;
193 	}
194 	return 0;
195 out:
196 	spufs_prune_dir(dir);
197 	return ret;
198 }
199 
200 static int spufs_dir_close(struct inode *inode, struct file *file)
201 {
202 	struct inode *dir;
203 	struct dentry *dentry;
204 	int ret;
205 
206 	dentry = file->f_dentry;
207 	dir = dentry->d_parent->d_inode;
208 
209 	ret = spufs_rmdir(dir, dentry);
210 	WARN_ON(ret);
211 
212 	return dcache_dir_close(inode, file);
213 }
214 
215 struct inode_operations spufs_dir_inode_operations = {
216 	.lookup = simple_lookup,
217 };
218 
219 struct file_operations spufs_context_fops = {
220 	.open		= dcache_dir_open,
221 	.release	= spufs_dir_close,
222 	.llseek		= dcache_dir_lseek,
223 	.read		= generic_read_dir,
224 	.readdir	= dcache_readdir,
225 	.fsync		= simple_sync_file,
226 };
227 
228 static int
229 spufs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
230 {
231 	int ret;
232 	struct inode *inode;
233 	struct spu_context *ctx;
234 
235 	ret = -ENOSPC;
236 	inode = spufs_new_inode(dir->i_sb, mode | S_IFDIR);
237 	if (!inode)
238 		goto out;
239 
240 	if (dir->i_mode & S_ISGID) {
241 		inode->i_gid = dir->i_gid;
242 		inode->i_mode &= S_ISGID;
243 	}
244 	ctx = alloc_spu_context(inode->i_mapping);
245 	SPUFS_I(inode)->i_ctx = ctx;
246 	if (!ctx)
247 		goto out_iput;
248 
249 	inode->i_op = &spufs_dir_inode_operations;
250 	inode->i_fop = &simple_dir_operations;
251 	ret = spufs_fill_dir(dentry, spufs_dir_contents, mode, ctx);
252 	if (ret)
253 		goto out_free_ctx;
254 
255 	d_instantiate(dentry, inode);
256 	dget(dentry);
257 	dir->i_nlink++;
258 	dentry->d_inode->i_nlink++;
259 	goto out;
260 
261 out_free_ctx:
262 	put_spu_context(ctx);
263 out_iput:
264 	iput(inode);
265 out:
266 	return ret;
267 }
268 
269 static int spufs_context_open(struct dentry *dentry, struct vfsmount *mnt)
270 {
271 	int ret;
272 	struct file *filp;
273 
274 	ret = get_unused_fd();
275 	if (ret < 0) {
276 		dput(dentry);
277 		mntput(mnt);
278 		goto out;
279 	}
280 
281 	filp = dentry_open(dentry, mnt, O_RDONLY);
282 	if (IS_ERR(filp)) {
283 		put_unused_fd(ret);
284 		ret = PTR_ERR(filp);
285 		goto out;
286 	}
287 
288 	filp->f_op = &spufs_context_fops;
289 	fd_install(ret, filp);
290 out:
291 	return ret;
292 }
293 
294 static struct file_system_type spufs_type;
295 
296 long spufs_create_thread(struct nameidata *nd,
297 			 unsigned int flags, mode_t mode)
298 {
299 	struct dentry *dentry;
300 	int ret;
301 
302 	/* need to be at the root of spufs */
303 	ret = -EINVAL;
304 	if (nd->dentry->d_sb->s_type != &spufs_type ||
305 	    nd->dentry != nd->dentry->d_sb->s_root)
306 		goto out;
307 
308 	dentry = lookup_create(nd, 1);
309 	ret = PTR_ERR(dentry);
310 	if (IS_ERR(dentry))
311 		goto out_dir;
312 
313 	ret = -EEXIST;
314 	if (dentry->d_inode)
315 		goto out_dput;
316 
317 	mode &= ~current->fs->umask;
318 	ret = spufs_mkdir(nd->dentry->d_inode, dentry, mode & S_IRWXUGO);
319 	if (ret)
320 		goto out_dput;
321 
322 	/*
323 	 * get references for dget and mntget, will be released
324 	 * in error path of *_open().
325 	 */
326 	ret = spufs_context_open(dget(dentry), mntget(nd->mnt));
327 	if (ret < 0)
328 		spufs_rmdir(nd->dentry->d_inode, dentry);
329 
330 out_dput:
331 	dput(dentry);
332 out_dir:
333 	mutex_unlock(&nd->dentry->d_inode->i_mutex);
334 out:
335 	return ret;
336 }
337 
338 /* File system initialization */
339 enum {
340 	Opt_uid, Opt_gid, Opt_err,
341 };
342 
343 static match_table_t spufs_tokens = {
344 	{ Opt_uid, "uid=%d" },
345 	{ Opt_gid, "gid=%d" },
346 	{ Opt_err, NULL  },
347 };
348 
349 static int
350 spufs_parse_options(char *options, struct inode *root)
351 {
352 	char *p;
353 	substring_t args[MAX_OPT_ARGS];
354 
355 	while ((p = strsep(&options, ",")) != NULL) {
356 		int token, option;
357 
358 		if (!*p)
359 			continue;
360 
361 		token = match_token(p, spufs_tokens, args);
362 		switch (token) {
363 		case Opt_uid:
364 			if (match_int(&args[0], &option))
365 				return 0;
366 			root->i_uid = option;
367 			break;
368 		case Opt_gid:
369 			if (match_int(&args[0], &option))
370 				return 0;
371 			root->i_gid = option;
372 			break;
373 		default:
374 			return 0;
375 		}
376 	}
377 	return 1;
378 }
379 
380 static int
381 spufs_create_root(struct super_block *sb, void *data)
382 {
383 	struct inode *inode;
384 	int ret;
385 
386 	ret = -ENOMEM;
387 	inode = spufs_new_inode(sb, S_IFDIR | 0775);
388 	if (!inode)
389 		goto out;
390 
391 	inode->i_op = &spufs_dir_inode_operations;
392 	inode->i_fop = &simple_dir_operations;
393 	SPUFS_I(inode)->i_ctx = NULL;
394 
395 	ret = -EINVAL;
396 	if (!spufs_parse_options(data, inode))
397 		goto out_iput;
398 
399 	ret = -ENOMEM;
400 	sb->s_root = d_alloc_root(inode);
401 	if (!sb->s_root)
402 		goto out_iput;
403 
404 	return 0;
405 out_iput:
406 	iput(inode);
407 out:
408 	return ret;
409 }
410 
411 static int
412 spufs_fill_super(struct super_block *sb, void *data, int silent)
413 {
414 	static struct super_operations s_ops = {
415 		.alloc_inode = spufs_alloc_inode,
416 		.destroy_inode = spufs_destroy_inode,
417 		.statfs = simple_statfs,
418 		.delete_inode = spufs_delete_inode,
419 		.drop_inode = generic_delete_inode,
420 	};
421 
422 	sb->s_maxbytes = MAX_LFS_FILESIZE;
423 	sb->s_blocksize = PAGE_CACHE_SIZE;
424 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
425 	sb->s_magic = SPUFS_MAGIC;
426 	sb->s_op = &s_ops;
427 
428 	return spufs_create_root(sb, data);
429 }
430 
431 static struct super_block *
432 spufs_get_sb(struct file_system_type *fstype, int flags,
433 		const char *name, void *data)
434 {
435 	return get_sb_single(fstype, flags, data, spufs_fill_super);
436 }
437 
438 static struct file_system_type spufs_type = {
439 	.owner = THIS_MODULE,
440 	.name = "spufs",
441 	.get_sb = spufs_get_sb,
442 	.kill_sb = kill_litter_super,
443 };
444 
445 static int spufs_init(void)
446 {
447 	int ret;
448 	ret = -ENOMEM;
449 	spufs_inode_cache = kmem_cache_create("spufs_inode_cache",
450 			sizeof(struct spufs_inode_info), 0,
451 			SLAB_HWCACHE_ALIGN, spufs_init_once, NULL);
452 
453 	if (!spufs_inode_cache)
454 		goto out;
455 	if (spu_sched_init() != 0) {
456 		kmem_cache_destroy(spufs_inode_cache);
457 		goto out;
458 	}
459 	ret = register_filesystem(&spufs_type);
460 	if (ret)
461 		goto out_cache;
462 	ret = register_spu_syscalls(&spufs_calls);
463 	if (ret)
464 		goto out_fs;
465 	return 0;
466 out_fs:
467 	unregister_filesystem(&spufs_type);
468 out_cache:
469 	kmem_cache_destroy(spufs_inode_cache);
470 out:
471 	return ret;
472 }
473 module_init(spufs_init);
474 
475 static void spufs_exit(void)
476 {
477 	spu_sched_exit();
478 	unregister_spu_syscalls(&spufs_calls);
479 	unregister_filesystem(&spufs_type);
480 	kmem_cache_destroy(spufs_inode_cache);
481 }
482 module_exit(spufs_exit);
483 
484 MODULE_LICENSE("GPL");
485 MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
486 
487