xattr.c 24.2 KB
Newer Older
1
// SPDX-License-Identifier: GPL-2.0
Linus Torvalds's avatar
Linus Torvalds committed
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
/*
 * linux/fs/reiserfs/xattr.c
 *
 * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
 *
 */

/*
 * In order to implement EA/ACLs in a clean, backwards compatible manner,
 * they are implemented as files in a "private" directory.
 * Each EA is in it's own file, with the directory layout like so (/ is assumed
 * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
 * directories named using the capital-hex form of the objectid and
 * generation number are used. Inside each directory are individual files
 * named with the name of the extended attribute.
 *
 * So, for objectid 12648430, we could have:
 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
 * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
 * .. or similar.
 *
 * The file contents are the text of the EA. The size is known based on the
 * stat data describing the file.
 *
 * In the case of system.posix_acl_access and system.posix_acl_default, since
 * these are special cases for filesystem ACLs, they are interpreted by the
 * kernel, in addition, they are negatively and positively cached and attached
 * to the inode so that unnecessary lookups are avoided.
31 32
 *
 * Locking works like so:
33 34
 * Directory components (xattr root, xattr dir) are protectd by their i_mutex.
 * The xattrs themselves are protected by the xattr_sem.
Linus Torvalds's avatar
Linus Torvalds committed
35 36
 */

37
#include "reiserfs.h"
38
#include <linux/capability.h>
Linus Torvalds's avatar
Linus Torvalds committed
39 40 41
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/errno.h>
42
#include <linux/gfp.h>
Linus Torvalds's avatar
Linus Torvalds committed
43 44 45 46
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
47
#include "xattr.h"
48
#include "acl.h"
49
#include <linux/uaccess.h>
50
#include <net/checksum.h>
Linus Torvalds's avatar
Linus Torvalds committed
51
#include <linux/stat.h>
52
#include <linux/quotaops.h>
53
#include <linux/security.h>
54
#include <linux/posix_acl_xattr.h>
Linus Torvalds's avatar
Linus Torvalds committed
55 56 57 58 59

#define PRIVROOT_NAME ".reiserfs_priv"
#define XAROOT_NAME   "xattrs"


60 61
/*
 * Helpers for inode ops. We do this so that we don't have all the VFS
62
 * overhead and also for proper i_mutex annotation.
63 64
 * dir->i_mutex must be held for all of them.
 */
65
#ifdef CONFIG_REISERFS_FS_XATTR
66
static int xattr_create(struct inode *dir, struct dentry *dentry, int mode)
Linus Torvalds's avatar
Linus Torvalds committed
67
{
Al Viro's avatar
Al Viro committed
68
	BUG_ON(!inode_is_locked(dir));
69
	return dir->i_op->create(dir, dentry, mode, true);
70
}
71
#endif
72

73
static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
74
{
Al Viro's avatar
Al Viro committed
75
	BUG_ON(!inode_is_locked(dir));
76 77
	return dir->i_op->mkdir(dir, dentry, mode);
}
78

79 80
/*
 * We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr
81 82
 * mutation ops aren't called during rename or splace, which are the
 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's
83 84
 * better than allocating another subclass just for this code.
 */
85 86 87
static int xattr_unlink(struct inode *dir, struct dentry *dentry)
{
	int error;
88

Al Viro's avatar
Al Viro committed
89
	BUG_ON(!inode_is_locked(dir));
90

Al Viro's avatar
Al Viro committed
91
	inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
92
	error = dir->i_op->unlink(dir, dentry);
Al Viro's avatar
Al Viro committed
93
	inode_unlock(d_inode(dentry));
94 95 96 97 98 99 100 101 102

	if (!error)
		d_delete(dentry);
	return error;
}

static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
{
	int error;
103

Al Viro's avatar
Al Viro committed
104
	BUG_ON(!inode_is_locked(dir));
105

Al Viro's avatar
Al Viro committed
106
	inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
107 108
	error = dir->i_op->rmdir(dir, dentry);
	if (!error)
109
		d_inode(dentry)->i_flags |= S_DEAD;
Al Viro's avatar
Al Viro committed
110
	inode_unlock(d_inode(dentry));
111 112 113 114 115 116 117 118
	if (!error)
		d_delete(dentry);

	return error;
}

#define xattr_may_create(flags)	(!flags || flags & XATTR_CREATE)

119
static struct dentry *open_xa_root(struct super_block *sb, int flags)
120
{
121 122
	struct dentry *privroot = REISERFS_SB(sb)->priv_root;
	struct dentry *xaroot;
123

124
	if (d_really_is_negative(privroot))
125
		return ERR_PTR(-ENODATA);
126

Al Viro's avatar
Al Viro committed
127
	inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR);
128

129
	xaroot = dget(REISERFS_SB(sb)->xattr_root);
130 131
	if (!xaroot)
		xaroot = ERR_PTR(-ENODATA);
132
	else if (d_really_is_negative(xaroot)) {
133
		int err = -ENODATA;
134

135
		if (xattr_may_create(flags))
136
			err = xattr_mkdir(d_inode(privroot), xaroot, 0700);
137
		if (err) {
138 139
			dput(xaroot);
			xaroot = ERR_PTR(err);
140
		}
141
	}
142

Al Viro's avatar
Al Viro committed
143
	inode_unlock(d_inode(privroot));
144
	return xaroot;
Linus Torvalds's avatar
Linus Torvalds committed
145 146
}

147
static struct dentry *open_xa_dir(const struct inode *inode, int flags)
Linus Torvalds's avatar
Linus Torvalds committed
148
{
149 150 151
	struct dentry *xaroot, *xadir;
	char namebuf[17];

152
	xaroot = open_xa_root(inode->i_sb, flags);
153
	if (IS_ERR(xaroot))
154 155 156 157 158 159
		return xaroot;

	snprintf(namebuf, sizeof(namebuf), "%X.%X",
		 le32_to_cpu(INODE_PKEY(inode)->k_objectid),
		 inode->i_generation);

Al Viro's avatar
Al Viro committed
160
	inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR);
161 162

	xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
163
	if (!IS_ERR(xadir) && d_really_is_negative(xadir)) {
164
		int err = -ENODATA;
165

166
		if (xattr_may_create(flags))
167
			err = xattr_mkdir(d_inode(xaroot), xadir, 0700);
168 169 170 171 172 173
		if (err) {
			dput(xadir);
			xadir = ERR_PTR(err);
		}
	}

Al Viro's avatar
Al Viro committed
174
	inode_unlock(d_inode(xaroot));
175 176
	dput(xaroot);
	return xadir;
Linus Torvalds's avatar
Linus Torvalds committed
177 178
}

179 180
/*
 * The following are side effects of other operations that aren't explicitly
181
 * modifying extended attributes. This includes operations such as permissions
182 183
 * or ownership changes, object deletions, etc.
 */
184
struct reiserfs_dentry_buf {
Al Viro's avatar
Al Viro committed
185
	struct dir_context ctx;
186 187 188 189
	struct dentry *xadir;
	int count;
	struct dentry *dentries[8];
};
190

191
static int
192 193
fill_with_dentries(struct dir_context *ctx, const char *name, int namelen,
		   loff_t offset, u64 ino, unsigned int d_type)
194
{
195 196
	struct reiserfs_dentry_buf *dbuf =
		container_of(ctx, struct reiserfs_dentry_buf, ctx);
197
	struct dentry *dentry;
198

Al Viro's avatar
Al Viro committed
199
	WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir)));
200

201 202
	if (dbuf->count == ARRAY_SIZE(dbuf->dentries))
		return -ENOSPC;
203

204 205
	if (name[0] == '.' && (namelen < 2 ||
			       (namelen == 2 && name[1] == '.')))
206
		return 0;
207

208
	dentry = lookup_one_len(name, dbuf->xadir, namelen);
209
	if (IS_ERR(dentry)) {
210
		return PTR_ERR(dentry);
211
	} else if (d_really_is_negative(dentry)) {
212 213
		/* A directory entry exists, but no file? */
		reiserfs_error(dentry->d_sb, "xattr-20003",
Al Viro's avatar
Al Viro committed
214 215 216
			       "Corrupted directory: xattr %pd listed but "
			       "not found for file %pd.\n",
			       dentry, dbuf->xadir);
217 218
		dput(dentry);
		return -EIO;
219
	}
Linus Torvalds's avatar
Linus Torvalds committed
220

221 222
	dbuf->dentries[dbuf->count++] = dentry;
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
223 224
}

225 226
static void
cleanup_dentry_buf(struct reiserfs_dentry_buf *buf)
Linus Torvalds's avatar
Linus Torvalds committed
227
{
228
	int i;
229

230 231 232
	for (i = 0; i < buf->count; i++)
		if (buf->dentries[i])
			dput(buf->dentries[i]);
233 234
}

235 236 237
static int reiserfs_for_each_xattr(struct inode *inode,
				   int (*action)(struct dentry *, void *),
				   void *data)
238
{
239 240 241
	struct dentry *dir;
	int i, err = 0;
	struct reiserfs_dentry_buf buf = {
Al Viro's avatar
Al Viro committed
242
		.ctx.actor = fill_with_dentries,
243
	};
Linus Torvalds's avatar
Linus Torvalds committed
244

245 246 247
	/* Skip out, an xattr has no xattrs associated with it */
	if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
		return 0;
Linus Torvalds's avatar
Linus Torvalds committed
248

249
	dir = open_xa_dir(inode, XATTR_REPLACE);
250 251 252
	if (IS_ERR(dir)) {
		err = PTR_ERR(dir);
		goto out;
253
	} else if (d_really_is_negative(dir)) {
254 255
		err = 0;
		goto out_dir;
256
	}
Linus Torvalds's avatar
Linus Torvalds committed
257

Al Viro's avatar
Al Viro committed
258
	inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
259

260
	buf.xadir = dir;
261
	while (1) {
262
		err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
263 264 265 266 267
		if (err)
			break;
		if (!buf.count)
			break;
		for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) {
268
			struct dentry *dentry = buf.dentries[i];
Linus Torvalds's avatar
Linus Torvalds committed
269

270
			if (!d_is_dir(dentry))
271
				err = action(dentry, data);
Linus Torvalds's avatar
Linus Torvalds committed
272

273 274
			dput(dentry);
			buf.dentries[i] = NULL;
275
		}
276 277
		if (err)
			break;
278
		buf.count = 0;
279
	}
Al Viro's avatar
Al Viro committed
280
	inode_unlock(d_inode(dir));
Linus Torvalds's avatar
Linus Torvalds committed
281

282
	cleanup_dentry_buf(&buf);
Linus Torvalds's avatar
Linus Torvalds committed
283

284
	if (!err) {
285 286
		/*
		 * We start a transaction here to avoid a ABBA situation
287 288 289
		 * between the xattr root's i_mutex and the journal lock.
		 * This doesn't incur much additional overhead since the
		 * new transaction will just nest inside the
290 291
		 * outer transaction.
		 */
292 293 294
		int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
			     4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
		struct reiserfs_transaction_handle th;
295

296
		reiserfs_write_lock(inode->i_sb);
297
		err = journal_begin(&th, inode->i_sb, blocks);
298
		reiserfs_write_unlock(inode->i_sb);
299 300
		if (!err) {
			int jerror;
301

Al Viro's avatar
Al Viro committed
302
			inode_lock_nested(d_inode(dir->d_parent),
303
					  I_MUTEX_XATTR);
304
			err = action(dir, data);
305
			reiserfs_write_lock(inode->i_sb);
306
			jerror = journal_end(&th);
307
			reiserfs_write_unlock(inode->i_sb);
Al Viro's avatar
Al Viro committed
308
			inode_unlock(d_inode(dir->d_parent));
309 310
			err = jerror ?: err;
		}
311
	}
312 313
out_dir:
	dput(dir);
314
out:
315 316 317
	/* -ENODATA isn't an error */
	if (err == -ENODATA)
		err = 0;
318 319
	return err;
}
Linus Torvalds's avatar
Linus Torvalds committed
320

321
static int delete_one_xattr(struct dentry *dentry, void *data)
322
{
323
	struct inode *dir = d_inode(dentry->d_parent);
Linus Torvalds's avatar
Linus Torvalds committed
324

325
	/* This is the xattr dir, handle specially. */
326
	if (d_is_dir(dentry))
327
		return xattr_rmdir(dir, dentry);
Linus Torvalds's avatar
Linus Torvalds committed
328

329 330
	return xattr_unlink(dir, dentry);
}
331

332 333 334
static int chown_one_xattr(struct dentry *dentry, void *data)
{
	struct iattr *attrs = data;
335 336 337 338 339 340 341 342 343 344 345 346 347
	int ia_valid = attrs->ia_valid;
	int err;

	/*
	 * We only want the ownership bits. Otherwise, we'll do
	 * things like change a directory to a regular file if
	 * ATTR_MODE is set.
	 */
	attrs->ia_valid &= (ATTR_UID|ATTR_GID);
	err = reiserfs_setattr(dentry, attrs);
	attrs->ia_valid = ia_valid;

	return err;
348
}
Linus Torvalds's avatar
Linus Torvalds committed
349

350 351 352 353
/* No i_mutex, but the inode is unconnected. */
int reiserfs_delete_xattrs(struct inode *inode)
{
	int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL);
354

355 356 357
	if (err)
		reiserfs_warning(inode->i_sb, "jdm-20004",
				 "Couldn't delete all xattrs (%d)\n", err);
358 359
	return err;
}
Linus Torvalds's avatar
Linus Torvalds committed
360

361
/* inode->i_mutex: down */
362 363
int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
{
364
	int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs);
365

366 367 368
	if (err)
		reiserfs_warning(inode->i_sb, "jdm-20007",
				 "Couldn't chown all xattrs (%d)\n", err);
369
	return err;
Linus Torvalds's avatar
Linus Torvalds committed
370 371
}

372
#ifdef CONFIG_REISERFS_FS_XATTR
373 374
/*
 * Returns a dentry corresponding to a specific extended attribute file
375
 * for the inode. If flags allow, the file is created. Otherwise, a
376 377
 * valid or negative dentry, or an error is returned.
 */
378 379
static struct dentry *xattr_lookup(struct inode *inode, const char *name,
				    int flags)
Linus Torvalds's avatar
Linus Torvalds committed
380
{
381 382 383 384
	struct dentry *xadir, *xafile;
	int err = 0;

	xadir = open_xa_dir(inode, flags);
385
	if (IS_ERR(xadir))
386 387
		return ERR_CAST(xadir);

Al Viro's avatar
Al Viro committed
388
	inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
389 390
	xafile = lookup_one_len(name, xadir, strlen(name));
	if (IS_ERR(xafile)) {
391 392
		err = PTR_ERR(xafile);
		goto out;
393
	}
394

395
	if (d_really_is_positive(xafile) && (flags & XATTR_CREATE))
396
		err = -EEXIST;
397

398
	if (d_really_is_negative(xafile)) {
399
		err = -ENODATA;
400
		if (xattr_may_create(flags))
401
			err = xattr_create(d_inode(xadir), xafile,
402
					      0700|S_IFREG);
403 404
	}

405 406
	if (err)
		dput(xafile);
407
out:
Al Viro's avatar
Al Viro committed
408
	inode_unlock(d_inode(xadir));
409 410
	dput(xadir);
	if (err)
411
		return ERR_PTR(err);
412
	return xafile;
Linus Torvalds's avatar
Linus Torvalds committed
413 414 415
}

/* Internal operations on file data */
416
static inline void reiserfs_put_page(struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
417
{
418
	kunmap(page);
419
	put_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
420 421
}

422
static struct page *reiserfs_get_page(struct inode *dir, size_t n)
Linus Torvalds's avatar
Linus Torvalds committed
423
{
424 425
	struct address_space *mapping = dir->i_mapping;
	struct page *page;
426 427 428 429
	/*
	 * We can deadlock if we try to free dentries,
	 * and an unlink/rmdir has just occurred - GFP_NOFS avoids this
	 */
430
	mapping_set_gfp_mask(mapping, GFP_NOFS);
431
	page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL);
432 433 434 435 436 437 438
	if (!IS_ERR(page)) {
		kmap(page);
		if (PageError(page))
			goto fail;
	}
	return page;

439
fail:
440 441
	reiserfs_put_page(page);
	return ERR_PTR(-EIO);
Linus Torvalds's avatar
Linus Torvalds committed
442 443
}

444
static inline __u32 xattr_hash(const char *msg, int len)
Linus Torvalds's avatar
Linus Torvalds committed
445
{
446
	return csum_partial(msg, len, 0);
Linus Torvalds's avatar
Linus Torvalds committed
447 448
}

449 450 451
int reiserfs_commit_write(struct file *f, struct page *page,
			  unsigned from, unsigned to);

452 453
static void update_ctime(struct inode *inode)
{
454
	struct timespec now = current_time(inode);
455

Al Viro's avatar
Al Viro committed
456
	if (inode_unhashed(inode) || !inode->i_nlink ||
457 458 459
	    timespec_equal(&inode->i_ctime, &now))
		return;

460
	inode->i_ctime = current_time(inode);
461 462 463 464 465 466 467 468 469 470 471 472
	mark_inode_dirty(inode);
}

static int lookup_and_delete_xattr(struct inode *inode, const char *name)
{
	int err = 0;
	struct dentry *dentry, *xadir;

	xadir = open_xa_dir(inode, XATTR_REPLACE);
	if (IS_ERR(xadir))
		return PTR_ERR(xadir);

Al Viro's avatar
Al Viro committed
473
	inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
474 475 476 477 478 479
	dentry = lookup_one_len(name, xadir, strlen(name));
	if (IS_ERR(dentry)) {
		err = PTR_ERR(dentry);
		goto out_dput;
	}

480 481
	if (d_really_is_positive(dentry)) {
		err = xattr_unlink(d_inode(xadir), dentry);
482 483 484 485 486
		update_ctime(inode);
	}

	dput(dentry);
out_dput:
Al Viro's avatar
Al Viro committed
487
	inode_unlock(d_inode(xadir));
488 489 490 491
	dput(xadir);
	return err;
}

492

Linus Torvalds's avatar
Linus Torvalds committed
493 494 495
/* Generic extended attribute operations that can be used by xa plugins */

/*
496
 * inode->i_mutex: down
Linus Torvalds's avatar
Linus Torvalds committed
497 498
 */
int
499 500 501
reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th,
			  struct inode *inode, const char *name,
			  const void *buffer, size_t buffer_size, int flags)
Linus Torvalds's avatar
Linus Torvalds committed
502
{
503
	int err = 0;
504
	struct dentry *dentry;
505 506 507 508
	struct page *page;
	char *data;
	size_t file_pos = 0;
	size_t buffer_pos = 0;
509
	size_t new_size;
510 511 512 513 514
	__u32 xahash = 0;

	if (get_inode_sd_version(inode) == STAT_DATA_V1)
		return -EOPNOTSUPP;

515 516 517 518 519
	if (!buffer) {
		err = lookup_and_delete_xattr(inode, name);
		return err;
	}

520
	dentry = xattr_lookup(inode, name, flags);
521
	if (IS_ERR(dentry))
522
		return PTR_ERR(dentry);
523

524
	down_write(&REISERFS_I(inode)->i_xattr_sem);
525

526
	xahash = xattr_hash(buffer, buffer_size);
527 528 529
	while (buffer_pos < buffer_size || buffer_pos == 0) {
		size_t chunk;
		size_t skip = 0;
530
		size_t page_offset = (file_pos & (PAGE_SIZE - 1));
531

532 533
		if (buffer_size - buffer_pos > PAGE_SIZE)
			chunk = PAGE_SIZE;
534 535 536
		else
			chunk = buffer_size - buffer_pos;

537
		page = reiserfs_get_page(d_inode(dentry), file_pos);
538 539
		if (IS_ERR(page)) {
			err = PTR_ERR(page);
540
			goto out_unlock;
541 542 543 544 545 546 547
		}

		lock_page(page);
		data = page_address(page);

		if (file_pos == 0) {
			struct reiserfs_xattr_header *rxh;
548

549
			skip = file_pos = sizeof(struct reiserfs_xattr_header);
550 551
			if (chunk + skip > PAGE_SIZE)
				chunk = PAGE_SIZE - skip;
552 553 554 555 556
			rxh = (struct reiserfs_xattr_header *)data;
			rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
			rxh->h_hash = cpu_to_le32(xahash);
		}

557
		reiserfs_write_lock(inode->i_sb);
558
		err = __reiserfs_write_begin(page, page_offset, chunk + skip);
559 560 561
		if (!err) {
			if (buffer)
				memcpy(data + skip, buffer + buffer_pos, chunk);
562 563 564
			err = reiserfs_commit_write(NULL, page, page_offset,
						    page_offset + chunk +
						    skip);
565
		}
566
		reiserfs_write_unlock(inode->i_sb);
567 568 569 570 571 572 573 574 575
		unlock_page(page);
		reiserfs_put_page(page);
		buffer_pos += chunk;
		file_pos += chunk;
		skip = 0;
		if (err || buffer_size == 0 || !buffer)
			break;
	}

576
	new_size = buffer_size + sizeof(struct reiserfs_xattr_header);
577
	if (!err && new_size < i_size_read(d_inode(dentry))) {
578
		struct iattr newattrs = {
579
			.ia_ctime = current_time(inode),
580
			.ia_size = new_size,
581 582
			.ia_valid = ATTR_SIZE | ATTR_CTIME,
		};
583

Al Viro's avatar
Al Viro committed
584
		inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR);
585
		inode_dio_wait(d_inode(dentry));
586

587
		err = reiserfs_setattr(dentry, &newattrs);
Al Viro's avatar
Al Viro committed
588
		inode_unlock(d_inode(dentry));
589 590 591
	} else
		update_ctime(inode);
out_unlock:
592
	up_write(&REISERFS_I(inode)->i_xattr_sem);
593
	dput(dentry);
594 595
	return err;
}
596

597 598 599
/* We need to start a transaction to maintain lock ordering */
int reiserfs_xattr_set(struct inode *inode, const char *name,
		       const void *buffer, size_t buffer_size, int flags)
600
{
601 602 603 604 605 606 607 608 609 610

	struct reiserfs_transaction_handle th;
	int error, error2;
	size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);

	if (!(flags & XATTR_REPLACE))
		jbegin_count += reiserfs_xattr_jcreate_nblocks(inode);

	reiserfs_write_lock(inode->i_sb);
	error = journal_begin(&th, inode->i_sb, jbegin_count);
611
	reiserfs_write_unlock(inode->i_sb);
612 613
	if (error) {
		return error;
Linus Torvalds's avatar
Linus Torvalds committed
614
	}
615

616 617
	error = reiserfs_xattr_set_handle(&th, inode, name,
					  buffer, buffer_size, flags);
618

619
	reiserfs_write_lock(inode->i_sb);
620
	error2 = journal_end(&th);
621
	reiserfs_write_unlock(inode->i_sb);
622 623 624 625
	if (error == 0)
		error = error2;

	return error;
Linus Torvalds's avatar
Linus Torvalds committed
626 627 628
}

/*
629
 * inode->i_mutex: down
Linus Torvalds's avatar
Linus Torvalds committed
630 631
 */
int
632
reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer,
633
		   size_t buffer_size)
Linus Torvalds's avatar
Linus Torvalds committed
634
{
635
	ssize_t err = 0;
636
	struct dentry *dentry;
637 638 639 640 641 642 643 644 645
	size_t isize;
	size_t file_pos = 0;
	size_t buffer_pos = 0;
	struct page *page;
	__u32 hash = 0;

	if (name == NULL)
		return -EINVAL;

646 647 648 649
	/*
	 * We can't have xattrs attached to v1 items since they don't have
	 * generation numbers
	 */
650 651 652
	if (get_inode_sd_version(inode) == STAT_DATA_V1)
		return -EOPNOTSUPP;

653
	dentry = xattr_lookup(inode, name, XATTR_REPLACE);
654 655
	if (IS_ERR(dentry)) {
		err = PTR_ERR(dentry);
656 657 658
		goto out;
	}

659
	down_read(&REISERFS_I(inode)->i_xattr_sem);
660

661
	isize = i_size_read(d_inode(dentry));
662 663 664 665

	/* Just return the size needed */
	if (buffer == NULL) {
		err = isize - sizeof(struct reiserfs_xattr_header);
666
		goto out_unlock;
667 668 669 670
	}

	if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
		err = -ERANGE;
671
		goto out_unlock;
672 673 674 675 676 677
	}

	while (file_pos < isize) {
		size_t chunk;
		char *data;
		size_t skip = 0;
678

679 680
		if (isize - file_pos > PAGE_SIZE)
			chunk = PAGE_SIZE;
681 682 683
		else
			chunk = isize - file_pos;

684
		page = reiserfs_get_page(d_inode(dentry), file_pos);
685 686
		if (IS_ERR(page)) {
			err = PTR_ERR(page);
687
			goto out_unlock;
688 689 690 691 692 693 694 695 696 697 698 699 700
		}

		lock_page(page);
		data = page_address(page);
		if (file_pos == 0) {
			struct reiserfs_xattr_header *rxh =
			    (struct reiserfs_xattr_header *)data;
			skip = file_pos = sizeof(struct reiserfs_xattr_header);
			chunk -= skip;
			/* Magic doesn't match up.. */
			if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
				unlock_page(page);
				reiserfs_put_page(page);
701
				reiserfs_warning(inode->i_sb, "jdm-20001",
702 703 704 705
						 "Invalid magic for xattr (%s) "
						 "associated with %k", name,
						 INODE_PKEY(inode));
				err = -EIO;
706
				goto out_unlock;
707 708 709 710 711 712 713 714 715 716 717 718 719 720
			}
			hash = le32_to_cpu(rxh->h_hash);
		}
		memcpy(buffer + buffer_pos, data + skip, chunk);
		unlock_page(page);
		reiserfs_put_page(page);
		file_pos += chunk;
		buffer_pos += chunk;
		skip = 0;
	}
	err = isize - sizeof(struct reiserfs_xattr_header);

	if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
	    hash) {
721
		reiserfs_warning(inode->i_sb, "jdm-20002",
722 723 724 725 726
				 "Invalid hash for xattr (%s) associated "
				 "with %k", name, INODE_PKEY(inode));
		err = -EIO;
	}

727 728
out_unlock:
	up_read(&REISERFS_I(inode)->i_xattr_sem);
729
	dput(dentry);
730

731
out:
732
	return err;
Linus Torvalds's avatar
Linus Torvalds committed
733 734
}

735 736 737 738 739 740 741 742 743 744 745 746 747
/*
 * In order to implement different sets of xattr operations for each xattr
 * prefix with the generic xattr API, a filesystem should create a
 * null-terminated array of struct xattr_handler (one for each prefix) and
 * hang a pointer to it off of the s_xattr field of the superblock.
 *
 * The generic_fooxattr() functions will use this list to dispatch xattr
 * operations to the correct xattr_handler.
 */
#define for_each_xattr_handler(handlers, handler)		\
		for ((handler) = *(handlers)++;			\
			(handler) != NULL;			\
			(handler) = *(handlers)++)
Linus Torvalds's avatar
Linus Torvalds committed
748

749
/* This is the implementation for the xattr plugin infrastructure */
750 751
static inline const struct xattr_handler *
find_xattr_handler_prefix(const struct xattr_handler **handlers,
752
			   const char *name)
Linus Torvalds's avatar
Linus Torvalds committed
753
{
754
	const struct xattr_handler *xah;
755

756 757
	if (!handlers)
		return NULL;
758

759
	for_each_xattr_handler(handlers, xah) {
760 761
		const char *prefix = xattr_prefix(xah);
		if (strncmp(prefix, name, strlen(prefix)) == 0)
762
			break;
763 764
	}

765
	return xah;
766
}
Linus Torvalds's avatar
Linus Torvalds committed
767

768
struct listxattr_buf {
Al Viro's avatar
Al Viro committed
769
	struct dir_context ctx;
770 771 772
	size_t size;
	size_t pos;
	char *buf;
773
	struct dentry *dentry;
Linus Torvalds's avatar
Linus Torvalds committed
774 775
};

776 777 778
static int listxattr_filler(struct dir_context *ctx, const char *name,
			    int namelen, loff_t offset, u64 ino,
			    unsigned int d_type)
Linus Torvalds's avatar
Linus Torvalds committed
779
{
780 781
	struct listxattr_buf *b =
		container_of(ctx, struct listxattr_buf, ctx);
782
	size_t size;
783

784 785
	if (name[0] != '.' ||
	    (namelen != 1 && (name[1] != '.' || namelen != 2))) {
786
		const struct xattr_handler *handler;
787

788
		handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr,
789
						    name);
790 791
		if (!handler /* Unsupported xattr name */ ||
		    (handler->list && !handler->list(b->dentry)))
792
			return 0;
793
		size = namelen + 1;
794 795 796
		if (b->buf) {
			if (size > b->size)
				return -ERANGE;
797 798
			memcpy(b->buf + b->pos, name, namelen);
			b->buf[b->pos + namelen] = 0;
799
		}
800 801
		b->pos += size;
	}
802
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
803
}
804

Linus Torvalds's avatar
Linus Torvalds committed
805 806 807
/*
 * Inode operation listxattr()
 *
808 809 810
 * We totally ignore the generic listxattr here because it would be stupid
 * not to. Since the xattrs are organized in a directory, we can just
 * readdir to find them.
Linus Torvalds's avatar
Linus Torvalds committed
811
 */
812
ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
Linus Torvalds's avatar
Linus Torvalds committed
813
{
814 815
	struct dentry *dir;
	int err = 0;
816
	struct listxattr_buf buf = {
Al Viro's avatar
Al Viro committed
817
		.ctx.actor = listxattr_filler,
818
		.dentry = dentry,
819 820 821
		.buf = buffer,
		.size = buffer ? size : 0,
	};
822

823
	if (d_really_is_negative(dentry))
824 825
		return -EINVAL;

826
	if (!dentry->d_sb->s_xattr ||
827
	    get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
828 829
		return -EOPNOTSUPP;

830
	dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE);
831 832 833
	if (IS_ERR(dir)) {
		err = PTR_ERR(dir);
		if (err == -ENODATA)
834
			err = 0;  /* Not an error if there aren't any xattrs */
835 836 837
		goto out;
	}

Al Viro's avatar
Al Viro committed
838
	inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
839
	err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
Al Viro's avatar
Al Viro committed
840
	inode_unlock(d_inode(dir));
841

842 843
	if (!err)
		err = buf.pos;
844

845
	dput(dir);
846
out:
847
	return err;
Linus Torvalds's avatar
Linus Torvalds committed
848 849
}

850
static int create_privroot(struct dentry *dentry)
Linus Torvalds's avatar
Linus Torvalds committed
851
{
852
	int err;
853
	struct inode *inode = d_inode(dentry->d_parent);
854

Al Viro's avatar
Al Viro committed
855
	WARN_ON_ONCE(!inode_is_locked(inode));
856

857
	err = xattr_mkdir(inode, dentry, 0700);
858
	if (err || d_really_is_negative(dentry)) {
859 860 861 862 863
		reiserfs_warning(dentry->d_sb, "jdm-20006",
				 "xattrs/ACLs enabled and couldn't "
				 "find/create .reiserfs_priv. "
				 "Failing mount.");
		return -EOPNOTSUPP;
864 865
	}

866
	d_inode(dentry)->i_flags |= S_PRIVATE;
867 868
	reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr "
		      "storage.\n", PRIVROOT_NAME);
869

870
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
871 872
}

Jeff Mahoney's avatar
Jeff Mahoney committed
873 874 875 876 877 878 879
#else
int __init reiserfs_xattr_register_handlers(void) { return 0; }
void reiserfs_xattr_unregister_handlers(void) {}
static int create_privroot(struct dentry *dentry) { return 0; }
#endif

/* Actual operations that are exported to VFS-land */
880
static const struct xattr_handler *reiserfs_xattr_handlers[] = {
Jeff Mahoney's avatar
Jeff Mahoney committed
881 882 883 884 885 886 887 888
#ifdef CONFIG_REISERFS_FS_XATTR
	&reiserfs_xattr_user_handler,
	&reiserfs_xattr_trusted_handler,
#endif
#ifdef CONFIG_REISERFS_FS_SECURITY
	&reiserfs_xattr_security_handler,
#endif
#ifdef CONFIG_REISERFS_FS_POSIX_ACL
889 890
	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_handler,
Jeff Mahoney's avatar
Jeff Mahoney committed
891 892 893 894
#endif
	NULL
};

895
static int xattr_mount_check(struct super_block *s)
Linus Torvalds's avatar
Linus Torvalds committed
896
{
897 898 899 900
	/*
	 * We need generation numbers to ensure that the oid mapping is correct
	 * v3.5 filesystems don't have them.
	 */
901 902
	if (old_format_only(s)) {
		if (reiserfs_xattrs_optional(s)) {
903 904 905 906
			/*
			 * Old format filesystem, but optional xattrs have
			 * been enabled. Error out.
			 */
907 908 909 910 911 912
			reiserfs_warning(s, "jdm-2005",
					 "xattrs/ACLs not supported "
					 "on pre-v3.6 format filesystems. "
					 "Failing mount.");
			return -EOPNOTSUPP;
		}
913 914 915
	}

	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
916 917
}

918
int reiserfs_permission(struct inode *inode, int mask)
919 920 921 922 923 924 925 926
{
	/*
	 * We don't do permission checks on the internal objects.
	 * Permissions are determined by the "owning" object.
	 */
	if (IS_PRIVATE(inode))
		return 0;

927
	return generic_permission(inode, mask);
928 929
}

930
static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags)
Linus Torvalds's avatar
Linus Torvalds committed
931
{
932
	return -EPERM;
Linus Torvalds's avatar
Linus Torvalds committed
933 934
}

935
static const struct dentry_operations xattr_lookup_poison_ops = {
936
	.d_revalidate = xattr_hide_revalidate,
Linus Torvalds's avatar
Linus Torvalds committed
937 938
};

939 940 941 942 943 944
int reiserfs_lookup_privroot(struct super_block *s)
{
	struct dentry *dentry;
	int err = 0;

	/* If we don't have the privroot located yet - go find it */
Al Viro's avatar
Al Viro committed
945
	inode_lock(d_inode(s->s_root));
946 947 948 949
	dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
				strlen(PRIVROOT_NAME));
	if (!IS_ERR(dentry)) {
		REISERFS_SB(s)->priv_root = dentry;
950
		d_set_d_op(dentry, &xattr_lookup_poison_ops);
951 952
		if (d_really_is_positive(dentry))
			d_inode(dentry)->i_flags |= S_PRIVATE;
953 954
	} else
		err = PTR_ERR(dentry);
Al Viro's avatar
Al Viro committed
955
	inode_unlock(d_inode(s->s_root));
956 957 958 959

	return err;
}

960 961
/*
 * We need to take a copy of the mount flags since things like
962
 * SB_RDONLY don't get set until *after* we're called.
963 964
 * mount_flags != mount_options
 */
965
int reiserfs_xattr_init(struct super_block *s, int mount_flags)
Linus Torvalds's avatar
Linus Torvalds committed
966
{
967
	int err = 0;
968
	struct dentry *privroot = REISERFS_SB(s)->priv_root;
969

970 971
	err = xattr_mount_check(s);
	if (err)
972 973
		goto error;

974
	if (d_really_is_negative(privroot) && !(mount_flags & SB_RDONLY)) {
Al Viro's avatar
Al Viro committed
975
		inode_lock(d_inode(s->s_root));
976
		err = create_privroot(REISERFS_SB(s)->priv_root);
Al Viro's avatar
Al Viro committed
977
		inode_unlock(d_inode(s->s_root));
978
	}
979

980
	if (d_really_is_positive(privroot)) {
981
		s->s_xattr = reiserfs_xattr_handlers;
Al Viro's avatar
Al Viro committed
982
		inode_lock(d_inode(privroot));
983 984
		if (!REISERFS_SB(s)->xattr_root) {
			struct dentry *dentry;
985

986 987 988 989 990 991 992
			dentry = lookup_one_len(XAROOT_NAME, privroot,
						strlen(XAROOT_NAME));
			if (!IS_ERR(dentry))
				REISERFS_SB(s)->xattr_root = dentry;
			else
				err = PTR_ERR(dentry);
		}
Al Viro's avatar
Al Viro committed
993
		inode_unlock(d_inode(privroot));
994
	}
995

996
error:
997
	if (err) {
998 999
		clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt);
		clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt);
1000 1001
	}

1002
	/* The super_block SB_POSIXACL must mirror the (no)acl mount option. */
1003
	if (reiserfs_posixacl(s))
1004
		s->s_flags |= SB_POSIXACL;
1005
	else
1006
		s->s_flags &= ~SB_POSIXACL;
1007 1008

	return err;
Linus Torvalds's avatar
Linus Torvalds committed
1009
}