xref: /openbmc/linux/fs/ceph/xattr.c (revision d23015c1)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ceph/ceph_debug.h>
3 #include <linux/ceph/pagelist.h>
4 
5 #include "super.h"
6 #include "mds_client.h"
7 
8 #include <linux/ceph/decode.h>
9 
10 #include <linux/xattr.h>
11 #include <linux/security.h>
12 #include <linux/posix_acl_xattr.h>
13 #include <linux/slab.h>
14 
15 #define XATTR_CEPH_PREFIX "ceph."
16 #define XATTR_CEPH_PREFIX_LEN (sizeof (XATTR_CEPH_PREFIX) - 1)
17 
18 static int __remove_xattr(struct ceph_inode_info *ci,
19 			  struct ceph_inode_xattr *xattr);
20 
21 static bool ceph_is_valid_xattr(const char *name)
22 {
23 	return !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
24 	       !strncmp(name, XATTR_CEPH_PREFIX, XATTR_CEPH_PREFIX_LEN) ||
25 	       !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
26 	       !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
27 }
28 
29 /*
30  * These define virtual xattrs exposing the recursive directory
31  * statistics and layout metadata.
32  */
33 struct ceph_vxattr {
34 	char *name;
35 	size_t name_size;	/* strlen(name) + 1 (for '\0') */
36 	ssize_t (*getxattr_cb)(struct ceph_inode_info *ci, char *val,
37 			       size_t size);
38 	bool (*exists_cb)(struct ceph_inode_info *ci);
39 	unsigned int flags;
40 };
41 
42 #define VXATTR_FLAG_READONLY		(1<<0)
43 #define VXATTR_FLAG_HIDDEN		(1<<1)
44 #define VXATTR_FLAG_RSTAT		(1<<2)
45 
46 /* layouts */
47 
48 static bool ceph_vxattrcb_layout_exists(struct ceph_inode_info *ci)
49 {
50 	struct ceph_file_layout *fl = &ci->i_layout;
51 	return (fl->stripe_unit > 0 || fl->stripe_count > 0 ||
52 		fl->object_size > 0 || fl->pool_id >= 0 ||
53 		rcu_dereference_raw(fl->pool_ns) != NULL);
54 }
55 
56 static ssize_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
57 				    size_t size)
58 {
59 	struct ceph_fs_client *fsc = ceph_sb_to_client(ci->vfs_inode.i_sb);
60 	struct ceph_osd_client *osdc = &fsc->client->osdc;
61 	struct ceph_string *pool_ns;
62 	s64 pool = ci->i_layout.pool_id;
63 	const char *pool_name;
64 	const char *ns_field = " pool_namespace=";
65 	char buf[128];
66 	size_t len, total_len = 0;
67 	ssize_t ret;
68 
69 	pool_ns = ceph_try_get_string(ci->i_layout.pool_ns);
70 
71 	dout("ceph_vxattrcb_layout %p\n", &ci->vfs_inode);
72 	down_read(&osdc->lock);
73 	pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, pool);
74 	if (pool_name) {
75 		len = snprintf(buf, sizeof(buf),
76 		"stripe_unit=%u stripe_count=%u object_size=%u pool=",
77 		ci->i_layout.stripe_unit, ci->i_layout.stripe_count,
78 	        ci->i_layout.object_size);
79 		total_len = len + strlen(pool_name);
80 	} else {
81 		len = snprintf(buf, sizeof(buf),
82 		"stripe_unit=%u stripe_count=%u object_size=%u pool=%lld",
83 		ci->i_layout.stripe_unit, ci->i_layout.stripe_count,
84 		ci->i_layout.object_size, pool);
85 		total_len = len;
86 	}
87 
88 	if (pool_ns)
89 		total_len += strlen(ns_field) + pool_ns->len;
90 
91 	ret = total_len;
92 	if (size >= total_len) {
93 		memcpy(val, buf, len);
94 		ret = len;
95 		if (pool_name) {
96 			len = strlen(pool_name);
97 			memcpy(val + ret, pool_name, len);
98 			ret += len;
99 		}
100 		if (pool_ns) {
101 			len = strlen(ns_field);
102 			memcpy(val + ret, ns_field, len);
103 			ret += len;
104 			memcpy(val + ret, pool_ns->str, pool_ns->len);
105 			ret += pool_ns->len;
106 		}
107 	}
108 	up_read(&osdc->lock);
109 	ceph_put_string(pool_ns);
110 	return ret;
111 }
112 
113 /*
114  * The convention with strings in xattrs is that they should not be NULL
115  * terminated, since we're returning the length with them. snprintf always
116  * NULL terminates however, so call it on a temporary buffer and then memcpy
117  * the result into place.
118  */
119 static int ceph_fmt_xattr(char *val, size_t size, const char *fmt, ...)
120 {
121 	int ret;
122 	va_list args;
123 	char buf[96]; /* NB: reevaluate size if new vxattrs are added */
124 
125 	va_start(args, fmt);
126 	ret = vsnprintf(buf, size ? sizeof(buf) : 0, fmt, args);
127 	va_end(args);
128 
129 	/* Sanity check */
130 	if (size && ret + 1 > sizeof(buf)) {
131 		WARN_ONCE(true, "Returned length too big (%d)", ret);
132 		return -E2BIG;
133 	}
134 
135 	if (ret <= size)
136 		memcpy(val, buf, ret);
137 	return ret;
138 }
139 
140 static ssize_t ceph_vxattrcb_layout_stripe_unit(struct ceph_inode_info *ci,
141 						char *val, size_t size)
142 {
143 	return ceph_fmt_xattr(val, size, "%u", ci->i_layout.stripe_unit);
144 }
145 
146 static ssize_t ceph_vxattrcb_layout_stripe_count(struct ceph_inode_info *ci,
147 						 char *val, size_t size)
148 {
149 	return ceph_fmt_xattr(val, size, "%u", ci->i_layout.stripe_count);
150 }
151 
152 static ssize_t ceph_vxattrcb_layout_object_size(struct ceph_inode_info *ci,
153 						char *val, size_t size)
154 {
155 	return ceph_fmt_xattr(val, size, "%u", ci->i_layout.object_size);
156 }
157 
158 static ssize_t ceph_vxattrcb_layout_pool(struct ceph_inode_info *ci,
159 					 char *val, size_t size)
160 {
161 	ssize_t ret;
162 	struct ceph_fs_client *fsc = ceph_sb_to_client(ci->vfs_inode.i_sb);
163 	struct ceph_osd_client *osdc = &fsc->client->osdc;
164 	s64 pool = ci->i_layout.pool_id;
165 	const char *pool_name;
166 
167 	down_read(&osdc->lock);
168 	pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, pool);
169 	if (pool_name) {
170 		ret = strlen(pool_name);
171 		if (ret <= size)
172 			memcpy(val, pool_name, ret);
173 	} else {
174 		ret = ceph_fmt_xattr(val, size, "%lld", pool);
175 	}
176 	up_read(&osdc->lock);
177 	return ret;
178 }
179 
180 static ssize_t ceph_vxattrcb_layout_pool_namespace(struct ceph_inode_info *ci,
181 						   char *val, size_t size)
182 {
183 	ssize_t ret = 0;
184 	struct ceph_string *ns = ceph_try_get_string(ci->i_layout.pool_ns);
185 
186 	if (ns) {
187 		ret = ns->len;
188 		if (ret <= size)
189 			memcpy(val, ns->str, ret);
190 		ceph_put_string(ns);
191 	}
192 	return ret;
193 }
194 
195 /* directories */
196 
197 static ssize_t ceph_vxattrcb_dir_entries(struct ceph_inode_info *ci, char *val,
198 					 size_t size)
199 {
200 	return ceph_fmt_xattr(val, size, "%lld", ci->i_files + ci->i_subdirs);
201 }
202 
203 static ssize_t ceph_vxattrcb_dir_files(struct ceph_inode_info *ci, char *val,
204 				       size_t size)
205 {
206 	return ceph_fmt_xattr(val, size, "%lld", ci->i_files);
207 }
208 
209 static ssize_t ceph_vxattrcb_dir_subdirs(struct ceph_inode_info *ci, char *val,
210 					 size_t size)
211 {
212 	return ceph_fmt_xattr(val, size, "%lld", ci->i_subdirs);
213 }
214 
215 static ssize_t ceph_vxattrcb_dir_rentries(struct ceph_inode_info *ci, char *val,
216 					  size_t size)
217 {
218 	return ceph_fmt_xattr(val, size, "%lld",
219 				ci->i_rfiles + ci->i_rsubdirs);
220 }
221 
222 static ssize_t ceph_vxattrcb_dir_rfiles(struct ceph_inode_info *ci, char *val,
223 					size_t size)
224 {
225 	return ceph_fmt_xattr(val, size, "%lld", ci->i_rfiles);
226 }
227 
228 static ssize_t ceph_vxattrcb_dir_rsubdirs(struct ceph_inode_info *ci, char *val,
229 					  size_t size)
230 {
231 	return ceph_fmt_xattr(val, size, "%lld", ci->i_rsubdirs);
232 }
233 
234 static ssize_t ceph_vxattrcb_dir_rbytes(struct ceph_inode_info *ci, char *val,
235 					size_t size)
236 {
237 	return ceph_fmt_xattr(val, size, "%lld", ci->i_rbytes);
238 }
239 
240 static ssize_t ceph_vxattrcb_dir_rctime(struct ceph_inode_info *ci, char *val,
241 					size_t size)
242 {
243 	return ceph_fmt_xattr(val, size, "%lld.%09ld", ci->i_rctime.tv_sec,
244 				ci->i_rctime.tv_nsec);
245 }
246 
247 /* dir pin */
248 static bool ceph_vxattrcb_dir_pin_exists(struct ceph_inode_info *ci)
249 {
250 	return ci->i_dir_pin != -ENODATA;
251 }
252 
253 static ssize_t ceph_vxattrcb_dir_pin(struct ceph_inode_info *ci, char *val,
254 				     size_t size)
255 {
256 	return ceph_fmt_xattr(val, size, "%d", (int)ci->i_dir_pin);
257 }
258 
259 /* quotas */
260 static bool ceph_vxattrcb_quota_exists(struct ceph_inode_info *ci)
261 {
262 	bool ret = false;
263 	spin_lock(&ci->i_ceph_lock);
264 	if ((ci->i_max_files || ci->i_max_bytes) &&
265 	    ci->i_vino.snap == CEPH_NOSNAP &&
266 	    ci->i_snap_realm &&
267 	    ci->i_snap_realm->ino == ci->i_vino.ino)
268 		ret = true;
269 	spin_unlock(&ci->i_ceph_lock);
270 	return ret;
271 }
272 
273 static ssize_t ceph_vxattrcb_quota(struct ceph_inode_info *ci, char *val,
274 				   size_t size)
275 {
276 	return ceph_fmt_xattr(val, size, "max_bytes=%llu max_files=%llu",
277 				ci->i_max_bytes, ci->i_max_files);
278 }
279 
280 static ssize_t ceph_vxattrcb_quota_max_bytes(struct ceph_inode_info *ci,
281 					     char *val, size_t size)
282 {
283 	return ceph_fmt_xattr(val, size, "%llu", ci->i_max_bytes);
284 }
285 
286 static ssize_t ceph_vxattrcb_quota_max_files(struct ceph_inode_info *ci,
287 					     char *val, size_t size)
288 {
289 	return ceph_fmt_xattr(val, size, "%llu", ci->i_max_files);
290 }
291 
292 /* snapshots */
293 static bool ceph_vxattrcb_snap_btime_exists(struct ceph_inode_info *ci)
294 {
295 	return (ci->i_snap_btime.tv_sec != 0 || ci->i_snap_btime.tv_nsec != 0);
296 }
297 
298 static ssize_t ceph_vxattrcb_snap_btime(struct ceph_inode_info *ci, char *val,
299 					size_t size)
300 {
301 	return ceph_fmt_xattr(val, size, "%lld.%09ld", ci->i_snap_btime.tv_sec,
302 				ci->i_snap_btime.tv_nsec);
303 }
304 
305 #define CEPH_XATTR_NAME(_type, _name)	XATTR_CEPH_PREFIX #_type "." #_name
306 #define CEPH_XATTR_NAME2(_type, _name, _name2)	\
307 	XATTR_CEPH_PREFIX #_type "." #_name "." #_name2
308 
309 #define XATTR_NAME_CEPH(_type, _name, _flags)				\
310 	{								\
311 		.name = CEPH_XATTR_NAME(_type, _name),			\
312 		.name_size = sizeof (CEPH_XATTR_NAME(_type, _name)), \
313 		.getxattr_cb = ceph_vxattrcb_ ## _type ## _ ## _name, \
314 		.exists_cb = NULL,					\
315 		.flags = (VXATTR_FLAG_READONLY | _flags),		\
316 	}
317 #define XATTR_RSTAT_FIELD(_type, _name)			\
318 	XATTR_NAME_CEPH(_type, _name, VXATTR_FLAG_RSTAT)
319 #define XATTR_LAYOUT_FIELD(_type, _name, _field)			\
320 	{								\
321 		.name = CEPH_XATTR_NAME2(_type, _name, _field),	\
322 		.name_size = sizeof (CEPH_XATTR_NAME2(_type, _name, _field)), \
323 		.getxattr_cb = ceph_vxattrcb_ ## _name ## _ ## _field, \
324 		.exists_cb = ceph_vxattrcb_layout_exists,	\
325 		.flags = VXATTR_FLAG_HIDDEN,			\
326 	}
327 #define XATTR_QUOTA_FIELD(_type, _name)					\
328 	{								\
329 		.name = CEPH_XATTR_NAME(_type, _name),			\
330 		.name_size = sizeof(CEPH_XATTR_NAME(_type, _name)),	\
331 		.getxattr_cb = ceph_vxattrcb_ ## _type ## _ ## _name,	\
332 		.exists_cb = ceph_vxattrcb_quota_exists,		\
333 		.flags = VXATTR_FLAG_HIDDEN,				\
334 	}
335 
336 static struct ceph_vxattr ceph_dir_vxattrs[] = {
337 	{
338 		.name = "ceph.dir.layout",
339 		.name_size = sizeof("ceph.dir.layout"),
340 		.getxattr_cb = ceph_vxattrcb_layout,
341 		.exists_cb = ceph_vxattrcb_layout_exists,
342 		.flags = VXATTR_FLAG_HIDDEN,
343 	},
344 	XATTR_LAYOUT_FIELD(dir, layout, stripe_unit),
345 	XATTR_LAYOUT_FIELD(dir, layout, stripe_count),
346 	XATTR_LAYOUT_FIELD(dir, layout, object_size),
347 	XATTR_LAYOUT_FIELD(dir, layout, pool),
348 	XATTR_LAYOUT_FIELD(dir, layout, pool_namespace),
349 	XATTR_NAME_CEPH(dir, entries, 0),
350 	XATTR_NAME_CEPH(dir, files, 0),
351 	XATTR_NAME_CEPH(dir, subdirs, 0),
352 	XATTR_RSTAT_FIELD(dir, rentries),
353 	XATTR_RSTAT_FIELD(dir, rfiles),
354 	XATTR_RSTAT_FIELD(dir, rsubdirs),
355 	XATTR_RSTAT_FIELD(dir, rbytes),
356 	XATTR_RSTAT_FIELD(dir, rctime),
357 	{
358 		.name = "ceph.dir.pin",
359 		.name_size = sizeof("ceph.dir.pin"),
360 		.getxattr_cb = ceph_vxattrcb_dir_pin,
361 		.exists_cb = ceph_vxattrcb_dir_pin_exists,
362 		.flags = VXATTR_FLAG_HIDDEN,
363 	},
364 	{
365 		.name = "ceph.quota",
366 		.name_size = sizeof("ceph.quota"),
367 		.getxattr_cb = ceph_vxattrcb_quota,
368 		.exists_cb = ceph_vxattrcb_quota_exists,
369 		.flags = VXATTR_FLAG_HIDDEN,
370 	},
371 	XATTR_QUOTA_FIELD(quota, max_bytes),
372 	XATTR_QUOTA_FIELD(quota, max_files),
373 	{
374 		.name = "ceph.snap.btime",
375 		.name_size = sizeof("ceph.snap.btime"),
376 		.getxattr_cb = ceph_vxattrcb_snap_btime,
377 		.exists_cb = ceph_vxattrcb_snap_btime_exists,
378 		.flags = VXATTR_FLAG_READONLY,
379 	},
380 	{ .name = NULL, 0 }	/* Required table terminator */
381 };
382 
383 /* files */
384 
385 static struct ceph_vxattr ceph_file_vxattrs[] = {
386 	{
387 		.name = "ceph.file.layout",
388 		.name_size = sizeof("ceph.file.layout"),
389 		.getxattr_cb = ceph_vxattrcb_layout,
390 		.exists_cb = ceph_vxattrcb_layout_exists,
391 		.flags = VXATTR_FLAG_HIDDEN,
392 	},
393 	XATTR_LAYOUT_FIELD(file, layout, stripe_unit),
394 	XATTR_LAYOUT_FIELD(file, layout, stripe_count),
395 	XATTR_LAYOUT_FIELD(file, layout, object_size),
396 	XATTR_LAYOUT_FIELD(file, layout, pool),
397 	XATTR_LAYOUT_FIELD(file, layout, pool_namespace),
398 	{
399 		.name = "ceph.snap.btime",
400 		.name_size = sizeof("ceph.snap.btime"),
401 		.getxattr_cb = ceph_vxattrcb_snap_btime,
402 		.exists_cb = ceph_vxattrcb_snap_btime_exists,
403 		.flags = VXATTR_FLAG_READONLY,
404 	},
405 	{ .name = NULL, 0 }	/* Required table terminator */
406 };
407 
408 static struct ceph_vxattr *ceph_inode_vxattrs(struct inode *inode)
409 {
410 	if (S_ISDIR(inode->i_mode))
411 		return ceph_dir_vxattrs;
412 	else if (S_ISREG(inode->i_mode))
413 		return ceph_file_vxattrs;
414 	return NULL;
415 }
416 
417 static struct ceph_vxattr *ceph_match_vxattr(struct inode *inode,
418 						const char *name)
419 {
420 	struct ceph_vxattr *vxattr = ceph_inode_vxattrs(inode);
421 
422 	if (vxattr) {
423 		while (vxattr->name) {
424 			if (!strcmp(vxattr->name, name))
425 				return vxattr;
426 			vxattr++;
427 		}
428 	}
429 
430 	return NULL;
431 }
432 
433 static int __set_xattr(struct ceph_inode_info *ci,
434 			   const char *name, int name_len,
435 			   const char *val, int val_len,
436 			   int flags, int update_xattr,
437 			   struct ceph_inode_xattr **newxattr)
438 {
439 	struct rb_node **p;
440 	struct rb_node *parent = NULL;
441 	struct ceph_inode_xattr *xattr = NULL;
442 	int c;
443 	int new = 0;
444 
445 	p = &ci->i_xattrs.index.rb_node;
446 	while (*p) {
447 		parent = *p;
448 		xattr = rb_entry(parent, struct ceph_inode_xattr, node);
449 		c = strncmp(name, xattr->name, min(name_len, xattr->name_len));
450 		if (c < 0)
451 			p = &(*p)->rb_left;
452 		else if (c > 0)
453 			p = &(*p)->rb_right;
454 		else {
455 			if (name_len == xattr->name_len)
456 				break;
457 			else if (name_len < xattr->name_len)
458 				p = &(*p)->rb_left;
459 			else
460 				p = &(*p)->rb_right;
461 		}
462 		xattr = NULL;
463 	}
464 
465 	if (update_xattr) {
466 		int err = 0;
467 
468 		if (xattr && (flags & XATTR_CREATE))
469 			err = -EEXIST;
470 		else if (!xattr && (flags & XATTR_REPLACE))
471 			err = -ENODATA;
472 		if (err) {
473 			kfree(name);
474 			kfree(val);
475 			kfree(*newxattr);
476 			return err;
477 		}
478 		if (update_xattr < 0) {
479 			if (xattr)
480 				__remove_xattr(ci, xattr);
481 			kfree(name);
482 			kfree(*newxattr);
483 			return 0;
484 		}
485 	}
486 
487 	if (!xattr) {
488 		new = 1;
489 		xattr = *newxattr;
490 		xattr->name = name;
491 		xattr->name_len = name_len;
492 		xattr->should_free_name = update_xattr;
493 
494 		ci->i_xattrs.count++;
495 		dout("__set_xattr count=%d\n", ci->i_xattrs.count);
496 	} else {
497 		kfree(*newxattr);
498 		*newxattr = NULL;
499 		if (xattr->should_free_val)
500 			kfree((void *)xattr->val);
501 
502 		if (update_xattr) {
503 			kfree((void *)name);
504 			name = xattr->name;
505 		}
506 		ci->i_xattrs.names_size -= xattr->name_len;
507 		ci->i_xattrs.vals_size -= xattr->val_len;
508 	}
509 	ci->i_xattrs.names_size += name_len;
510 	ci->i_xattrs.vals_size += val_len;
511 	if (val)
512 		xattr->val = val;
513 	else
514 		xattr->val = "";
515 
516 	xattr->val_len = val_len;
517 	xattr->dirty = update_xattr;
518 	xattr->should_free_val = (val && update_xattr);
519 
520 	if (new) {
521 		rb_link_node(&xattr->node, parent, p);
522 		rb_insert_color(&xattr->node, &ci->i_xattrs.index);
523 		dout("__set_xattr_val p=%p\n", p);
524 	}
525 
526 	dout("__set_xattr_val added %llx.%llx xattr %p %.*s=%.*s\n",
527 	     ceph_vinop(&ci->vfs_inode), xattr, name_len, name, val_len, val);
528 
529 	return 0;
530 }
531 
532 static struct ceph_inode_xattr *__get_xattr(struct ceph_inode_info *ci,
533 			   const char *name)
534 {
535 	struct rb_node **p;
536 	struct rb_node *parent = NULL;
537 	struct ceph_inode_xattr *xattr = NULL;
538 	int name_len = strlen(name);
539 	int c;
540 
541 	p = &ci->i_xattrs.index.rb_node;
542 	while (*p) {
543 		parent = *p;
544 		xattr = rb_entry(parent, struct ceph_inode_xattr, node);
545 		c = strncmp(name, xattr->name, xattr->name_len);
546 		if (c == 0 && name_len > xattr->name_len)
547 			c = 1;
548 		if (c < 0)
549 			p = &(*p)->rb_left;
550 		else if (c > 0)
551 			p = &(*p)->rb_right;
552 		else {
553 			dout("__get_xattr %s: found %.*s\n", name,
554 			     xattr->val_len, xattr->val);
555 			return xattr;
556 		}
557 	}
558 
559 	dout("__get_xattr %s: not found\n", name);
560 
561 	return NULL;
562 }
563 
564 static void __free_xattr(struct ceph_inode_xattr *xattr)
565 {
566 	BUG_ON(!xattr);
567 
568 	if (xattr->should_free_name)
569 		kfree((void *)xattr->name);
570 	if (xattr->should_free_val)
571 		kfree((void *)xattr->val);
572 
573 	kfree(xattr);
574 }
575 
576 static int __remove_xattr(struct ceph_inode_info *ci,
577 			  struct ceph_inode_xattr *xattr)
578 {
579 	if (!xattr)
580 		return -ENODATA;
581 
582 	rb_erase(&xattr->node, &ci->i_xattrs.index);
583 
584 	if (xattr->should_free_name)
585 		kfree((void *)xattr->name);
586 	if (xattr->should_free_val)
587 		kfree((void *)xattr->val);
588 
589 	ci->i_xattrs.names_size -= xattr->name_len;
590 	ci->i_xattrs.vals_size -= xattr->val_len;
591 	ci->i_xattrs.count--;
592 	kfree(xattr);
593 
594 	return 0;
595 }
596 
597 static char *__copy_xattr_names(struct ceph_inode_info *ci,
598 				char *dest)
599 {
600 	struct rb_node *p;
601 	struct ceph_inode_xattr *xattr = NULL;
602 
603 	p = rb_first(&ci->i_xattrs.index);
604 	dout("__copy_xattr_names count=%d\n", ci->i_xattrs.count);
605 
606 	while (p) {
607 		xattr = rb_entry(p, struct ceph_inode_xattr, node);
608 		memcpy(dest, xattr->name, xattr->name_len);
609 		dest[xattr->name_len] = '\0';
610 
611 		dout("dest=%s %p (%s) (%d/%d)\n", dest, xattr, xattr->name,
612 		     xattr->name_len, ci->i_xattrs.names_size);
613 
614 		dest += xattr->name_len + 1;
615 		p = rb_next(p);
616 	}
617 
618 	return dest;
619 }
620 
621 void __ceph_destroy_xattrs(struct ceph_inode_info *ci)
622 {
623 	struct rb_node *p, *tmp;
624 	struct ceph_inode_xattr *xattr = NULL;
625 
626 	p = rb_first(&ci->i_xattrs.index);
627 
628 	dout("__ceph_destroy_xattrs p=%p\n", p);
629 
630 	while (p) {
631 		xattr = rb_entry(p, struct ceph_inode_xattr, node);
632 		tmp = p;
633 		p = rb_next(tmp);
634 		dout("__ceph_destroy_xattrs next p=%p (%.*s)\n", p,
635 		     xattr->name_len, xattr->name);
636 		rb_erase(tmp, &ci->i_xattrs.index);
637 
638 		__free_xattr(xattr);
639 	}
640 
641 	ci->i_xattrs.names_size = 0;
642 	ci->i_xattrs.vals_size = 0;
643 	ci->i_xattrs.index_version = 0;
644 	ci->i_xattrs.count = 0;
645 	ci->i_xattrs.index = RB_ROOT;
646 }
647 
648 static int __build_xattrs(struct inode *inode)
649 	__releases(ci->i_ceph_lock)
650 	__acquires(ci->i_ceph_lock)
651 {
652 	u32 namelen;
653 	u32 numattr = 0;
654 	void *p, *end;
655 	u32 len;
656 	const char *name, *val;
657 	struct ceph_inode_info *ci = ceph_inode(inode);
658 	int xattr_version;
659 	struct ceph_inode_xattr **xattrs = NULL;
660 	int err = 0;
661 	int i;
662 
663 	dout("__build_xattrs() len=%d\n",
664 	     ci->i_xattrs.blob ? (int)ci->i_xattrs.blob->vec.iov_len : 0);
665 
666 	if (ci->i_xattrs.index_version >= ci->i_xattrs.version)
667 		return 0; /* already built */
668 
669 	__ceph_destroy_xattrs(ci);
670 
671 start:
672 	/* updated internal xattr rb tree */
673 	if (ci->i_xattrs.blob && ci->i_xattrs.blob->vec.iov_len > 4) {
674 		p = ci->i_xattrs.blob->vec.iov_base;
675 		end = p + ci->i_xattrs.blob->vec.iov_len;
676 		ceph_decode_32_safe(&p, end, numattr, bad);
677 		xattr_version = ci->i_xattrs.version;
678 		spin_unlock(&ci->i_ceph_lock);
679 
680 		xattrs = kcalloc(numattr, sizeof(struct ceph_inode_xattr *),
681 				 GFP_NOFS);
682 		err = -ENOMEM;
683 		if (!xattrs)
684 			goto bad_lock;
685 
686 		for (i = 0; i < numattr; i++) {
687 			xattrs[i] = kmalloc(sizeof(struct ceph_inode_xattr),
688 					    GFP_NOFS);
689 			if (!xattrs[i])
690 				goto bad_lock;
691 		}
692 
693 		spin_lock(&ci->i_ceph_lock);
694 		if (ci->i_xattrs.version != xattr_version) {
695 			/* lost a race, retry */
696 			for (i = 0; i < numattr; i++)
697 				kfree(xattrs[i]);
698 			kfree(xattrs);
699 			xattrs = NULL;
700 			goto start;
701 		}
702 		err = -EIO;
703 		while (numattr--) {
704 			ceph_decode_32_safe(&p, end, len, bad);
705 			namelen = len;
706 			name = p;
707 			p += len;
708 			ceph_decode_32_safe(&p, end, len, bad);
709 			val = p;
710 			p += len;
711 
712 			err = __set_xattr(ci, name, namelen, val, len,
713 					  0, 0, &xattrs[numattr]);
714 
715 			if (err < 0)
716 				goto bad;
717 		}
718 		kfree(xattrs);
719 	}
720 	ci->i_xattrs.index_version = ci->i_xattrs.version;
721 	ci->i_xattrs.dirty = false;
722 
723 	return err;
724 bad_lock:
725 	spin_lock(&ci->i_ceph_lock);
726 bad:
727 	if (xattrs) {
728 		for (i = 0; i < numattr; i++)
729 			kfree(xattrs[i]);
730 		kfree(xattrs);
731 	}
732 	ci->i_xattrs.names_size = 0;
733 	return err;
734 }
735 
736 static int __get_required_blob_size(struct ceph_inode_info *ci, int name_size,
737 				    int val_size)
738 {
739 	/*
740 	 * 4 bytes for the length, and additional 4 bytes per each xattr name,
741 	 * 4 bytes per each value
742 	 */
743 	int size = 4 + ci->i_xattrs.count*(4 + 4) +
744 			     ci->i_xattrs.names_size +
745 			     ci->i_xattrs.vals_size;
746 	dout("__get_required_blob_size c=%d names.size=%d vals.size=%d\n",
747 	     ci->i_xattrs.count, ci->i_xattrs.names_size,
748 	     ci->i_xattrs.vals_size);
749 
750 	if (name_size)
751 		size += 4 + 4 + name_size + val_size;
752 
753 	return size;
754 }
755 
756 /*
757  * If there are dirty xattrs, reencode xattrs into the prealloc_blob
758  * and swap into place.  It returns the old i_xattrs.blob (or NULL) so
759  * that it can be freed by the caller as the i_ceph_lock is likely to be
760  * held.
761  */
762 struct ceph_buffer *__ceph_build_xattrs_blob(struct ceph_inode_info *ci)
763 {
764 	struct rb_node *p;
765 	struct ceph_inode_xattr *xattr = NULL;
766 	struct ceph_buffer *old_blob = NULL;
767 	void *dest;
768 
769 	dout("__build_xattrs_blob %p\n", &ci->vfs_inode);
770 	if (ci->i_xattrs.dirty) {
771 		int need = __get_required_blob_size(ci, 0, 0);
772 
773 		BUG_ON(need > ci->i_xattrs.prealloc_blob->alloc_len);
774 
775 		p = rb_first(&ci->i_xattrs.index);
776 		dest = ci->i_xattrs.prealloc_blob->vec.iov_base;
777 
778 		ceph_encode_32(&dest, ci->i_xattrs.count);
779 		while (p) {
780 			xattr = rb_entry(p, struct ceph_inode_xattr, node);
781 
782 			ceph_encode_32(&dest, xattr->name_len);
783 			memcpy(dest, xattr->name, xattr->name_len);
784 			dest += xattr->name_len;
785 			ceph_encode_32(&dest, xattr->val_len);
786 			memcpy(dest, xattr->val, xattr->val_len);
787 			dest += xattr->val_len;
788 
789 			p = rb_next(p);
790 		}
791 
792 		/* adjust buffer len; it may be larger than we need */
793 		ci->i_xattrs.prealloc_blob->vec.iov_len =
794 			dest - ci->i_xattrs.prealloc_blob->vec.iov_base;
795 
796 		if (ci->i_xattrs.blob)
797 			old_blob = ci->i_xattrs.blob;
798 		ci->i_xattrs.blob = ci->i_xattrs.prealloc_blob;
799 		ci->i_xattrs.prealloc_blob = NULL;
800 		ci->i_xattrs.dirty = false;
801 		ci->i_xattrs.version++;
802 	}
803 
804 	return old_blob;
805 }
806 
807 static inline int __get_request_mask(struct inode *in) {
808 	struct ceph_mds_request *req = current->journal_info;
809 	int mask = 0;
810 	if (req && req->r_target_inode == in) {
811 		if (req->r_op == CEPH_MDS_OP_LOOKUP ||
812 		    req->r_op == CEPH_MDS_OP_LOOKUPINO ||
813 		    req->r_op == CEPH_MDS_OP_LOOKUPPARENT ||
814 		    req->r_op == CEPH_MDS_OP_GETATTR) {
815 			mask = le32_to_cpu(req->r_args.getattr.mask);
816 		} else if (req->r_op == CEPH_MDS_OP_OPEN ||
817 			   req->r_op == CEPH_MDS_OP_CREATE) {
818 			mask = le32_to_cpu(req->r_args.open.mask);
819 		}
820 	}
821 	return mask;
822 }
823 
824 ssize_t __ceph_getxattr(struct inode *inode, const char *name, void *value,
825 		      size_t size)
826 {
827 	struct ceph_inode_info *ci = ceph_inode(inode);
828 	struct ceph_inode_xattr *xattr;
829 	struct ceph_vxattr *vxattr = NULL;
830 	int req_mask;
831 	ssize_t err;
832 
833 	/* let's see if a virtual xattr was requested */
834 	vxattr = ceph_match_vxattr(inode, name);
835 	if (vxattr) {
836 		int mask = 0;
837 		if (vxattr->flags & VXATTR_FLAG_RSTAT)
838 			mask |= CEPH_STAT_RSTAT;
839 		err = ceph_do_getattr(inode, mask, true);
840 		if (err)
841 			return err;
842 		err = -ENODATA;
843 		if (!(vxattr->exists_cb && !vxattr->exists_cb(ci))) {
844 			err = vxattr->getxattr_cb(ci, value, size);
845 			if (size && size < err)
846 				err = -ERANGE;
847 		}
848 		return err;
849 	}
850 
851 	req_mask = __get_request_mask(inode);
852 
853 	spin_lock(&ci->i_ceph_lock);
854 	dout("getxattr %p ver=%lld index_ver=%lld\n", inode,
855 	     ci->i_xattrs.version, ci->i_xattrs.index_version);
856 
857 	if (ci->i_xattrs.version == 0 ||
858 	    !((req_mask & CEPH_CAP_XATTR_SHARED) ||
859 	      __ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1))) {
860 		spin_unlock(&ci->i_ceph_lock);
861 
862 		/* security module gets xattr while filling trace */
863 		if (current->journal_info) {
864 			pr_warn_ratelimited("sync getxattr %p "
865 					    "during filling trace\n", inode);
866 			return -EBUSY;
867 		}
868 
869 		/* get xattrs from mds (if we don't already have them) */
870 		err = ceph_do_getattr(inode, CEPH_STAT_CAP_XATTR, true);
871 		if (err)
872 			return err;
873 		spin_lock(&ci->i_ceph_lock);
874 	}
875 
876 	err = __build_xattrs(inode);
877 	if (err < 0)
878 		goto out;
879 
880 	err = -ENODATA;  /* == ENOATTR */
881 	xattr = __get_xattr(ci, name);
882 	if (!xattr)
883 		goto out;
884 
885 	err = -ERANGE;
886 	if (size && size < xattr->val_len)
887 		goto out;
888 
889 	err = xattr->val_len;
890 	if (size == 0)
891 		goto out;
892 
893 	memcpy(value, xattr->val, xattr->val_len);
894 
895 	if (current->journal_info &&
896 	    !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
897 	    security_ismaclabel(name + XATTR_SECURITY_PREFIX_LEN))
898 		ci->i_ceph_flags |= CEPH_I_SEC_INITED;
899 out:
900 	spin_unlock(&ci->i_ceph_lock);
901 	return err;
902 }
903 
904 ssize_t ceph_listxattr(struct dentry *dentry, char *names, size_t size)
905 {
906 	struct inode *inode = d_inode(dentry);
907 	struct ceph_inode_info *ci = ceph_inode(inode);
908 	bool len_only = (size == 0);
909 	u32 namelen;
910 	int err;
911 
912 	spin_lock(&ci->i_ceph_lock);
913 	dout("listxattr %p ver=%lld index_ver=%lld\n", inode,
914 	     ci->i_xattrs.version, ci->i_xattrs.index_version);
915 
916 	if (ci->i_xattrs.version == 0 ||
917 	    !__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1)) {
918 		spin_unlock(&ci->i_ceph_lock);
919 		err = ceph_do_getattr(inode, CEPH_STAT_CAP_XATTR, true);
920 		if (err)
921 			return err;
922 		spin_lock(&ci->i_ceph_lock);
923 	}
924 
925 	err = __build_xattrs(inode);
926 	if (err < 0)
927 		goto out;
928 
929 	/* add 1 byte for each xattr due to the null termination */
930 	namelen = ci->i_xattrs.names_size + ci->i_xattrs.count;
931 	if (!len_only) {
932 		if (namelen > size) {
933 			err = -ERANGE;
934 			goto out;
935 		}
936 		names = __copy_xattr_names(ci, names);
937 		size -= namelen;
938 	}
939 	err = namelen;
940 out:
941 	spin_unlock(&ci->i_ceph_lock);
942 	return err;
943 }
944 
945 static int ceph_sync_setxattr(struct inode *inode, const char *name,
946 			      const char *value, size_t size, int flags)
947 {
948 	struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
949 	struct ceph_inode_info *ci = ceph_inode(inode);
950 	struct ceph_mds_request *req;
951 	struct ceph_mds_client *mdsc = fsc->mdsc;
952 	struct ceph_pagelist *pagelist = NULL;
953 	int op = CEPH_MDS_OP_SETXATTR;
954 	int err;
955 
956 	if (size > 0) {
957 		/* copy value into pagelist */
958 		pagelist = ceph_pagelist_alloc(GFP_NOFS);
959 		if (!pagelist)
960 			return -ENOMEM;
961 
962 		err = ceph_pagelist_append(pagelist, value, size);
963 		if (err)
964 			goto out;
965 	} else if (!value) {
966 		if (flags & CEPH_XATTR_REPLACE)
967 			op = CEPH_MDS_OP_RMXATTR;
968 		else
969 			flags |= CEPH_XATTR_REMOVE;
970 	}
971 
972 	dout("setxattr value=%.*s\n", (int)size, value);
973 
974 	/* do request */
975 	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
976 	if (IS_ERR(req)) {
977 		err = PTR_ERR(req);
978 		goto out;
979 	}
980 
981 	req->r_path2 = kstrdup(name, GFP_NOFS);
982 	if (!req->r_path2) {
983 		ceph_mdsc_put_request(req);
984 		err = -ENOMEM;
985 		goto out;
986 	}
987 
988 	if (op == CEPH_MDS_OP_SETXATTR) {
989 		req->r_args.setxattr.flags = cpu_to_le32(flags);
990 		req->r_pagelist = pagelist;
991 		pagelist = NULL;
992 	}
993 
994 	req->r_inode = inode;
995 	ihold(inode);
996 	req->r_num_caps = 1;
997 	req->r_inode_drop = CEPH_CAP_XATTR_SHARED;
998 
999 	dout("xattr.ver (before): %lld\n", ci->i_xattrs.version);
1000 	err = ceph_mdsc_do_request(mdsc, NULL, req);
1001 	ceph_mdsc_put_request(req);
1002 	dout("xattr.ver (after): %lld\n", ci->i_xattrs.version);
1003 
1004 out:
1005 	if (pagelist)
1006 		ceph_pagelist_release(pagelist);
1007 	return err;
1008 }
1009 
1010 int __ceph_setxattr(struct inode *inode, const char *name,
1011 			const void *value, size_t size, int flags)
1012 {
1013 	struct ceph_vxattr *vxattr;
1014 	struct ceph_inode_info *ci = ceph_inode(inode);
1015 	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
1016 	struct ceph_cap_flush *prealloc_cf = NULL;
1017 	struct ceph_buffer *old_blob = NULL;
1018 	int issued;
1019 	int err;
1020 	int dirty = 0;
1021 	int name_len = strlen(name);
1022 	int val_len = size;
1023 	char *newname = NULL;
1024 	char *newval = NULL;
1025 	struct ceph_inode_xattr *xattr = NULL;
1026 	int required_blob_size;
1027 	bool check_realm = false;
1028 	bool lock_snap_rwsem = false;
1029 
1030 	if (ceph_snap(inode) != CEPH_NOSNAP)
1031 		return -EROFS;
1032 
1033 	vxattr = ceph_match_vxattr(inode, name);
1034 	if (vxattr) {
1035 		if (vxattr->flags & VXATTR_FLAG_READONLY)
1036 			return -EOPNOTSUPP;
1037 		if (value && !strncmp(vxattr->name, "ceph.quota", 10))
1038 			check_realm = true;
1039 	}
1040 
1041 	/* pass any unhandled ceph.* xattrs through to the MDS */
1042 	if (!strncmp(name, XATTR_CEPH_PREFIX, XATTR_CEPH_PREFIX_LEN))
1043 		goto do_sync_unlocked;
1044 
1045 	/* preallocate memory for xattr name, value, index node */
1046 	err = -ENOMEM;
1047 	newname = kmemdup(name, name_len + 1, GFP_NOFS);
1048 	if (!newname)
1049 		goto out;
1050 
1051 	if (val_len) {
1052 		newval = kmemdup(value, val_len, GFP_NOFS);
1053 		if (!newval)
1054 			goto out;
1055 	}
1056 
1057 	xattr = kmalloc(sizeof(struct ceph_inode_xattr), GFP_NOFS);
1058 	if (!xattr)
1059 		goto out;
1060 
1061 	prealloc_cf = ceph_alloc_cap_flush();
1062 	if (!prealloc_cf)
1063 		goto out;
1064 
1065 	spin_lock(&ci->i_ceph_lock);
1066 retry:
1067 	issued = __ceph_caps_issued(ci, NULL);
1068 	if (ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL))
1069 		goto do_sync;
1070 
1071 	if (!lock_snap_rwsem && !ci->i_head_snapc) {
1072 		lock_snap_rwsem = true;
1073 		if (!down_read_trylock(&mdsc->snap_rwsem)) {
1074 			spin_unlock(&ci->i_ceph_lock);
1075 			down_read(&mdsc->snap_rwsem);
1076 			spin_lock(&ci->i_ceph_lock);
1077 			goto retry;
1078 		}
1079 	}
1080 
1081 	dout("setxattr %p issued %s\n", inode, ceph_cap_string(issued));
1082 	__build_xattrs(inode);
1083 
1084 	required_blob_size = __get_required_blob_size(ci, name_len, val_len);
1085 
1086 	if (!ci->i_xattrs.prealloc_blob ||
1087 	    required_blob_size > ci->i_xattrs.prealloc_blob->alloc_len) {
1088 		struct ceph_buffer *blob;
1089 
1090 		spin_unlock(&ci->i_ceph_lock);
1091 		ceph_buffer_put(old_blob); /* Shouldn't be required */
1092 		dout(" pre-allocating new blob size=%d\n", required_blob_size);
1093 		blob = ceph_buffer_new(required_blob_size, GFP_NOFS);
1094 		if (!blob)
1095 			goto do_sync_unlocked;
1096 		spin_lock(&ci->i_ceph_lock);
1097 		/* prealloc_blob can't be released while holding i_ceph_lock */
1098 		if (ci->i_xattrs.prealloc_blob)
1099 			old_blob = ci->i_xattrs.prealloc_blob;
1100 		ci->i_xattrs.prealloc_blob = blob;
1101 		goto retry;
1102 	}
1103 
1104 	err = __set_xattr(ci, newname, name_len, newval, val_len,
1105 			  flags, value ? 1 : -1, &xattr);
1106 
1107 	if (!err) {
1108 		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_XATTR_EXCL,
1109 					       &prealloc_cf);
1110 		ci->i_xattrs.dirty = true;
1111 		inode->i_ctime = current_time(inode);
1112 	}
1113 
1114 	spin_unlock(&ci->i_ceph_lock);
1115 	ceph_buffer_put(old_blob);
1116 	if (lock_snap_rwsem)
1117 		up_read(&mdsc->snap_rwsem);
1118 	if (dirty)
1119 		__mark_inode_dirty(inode, dirty);
1120 	ceph_free_cap_flush(prealloc_cf);
1121 	return err;
1122 
1123 do_sync:
1124 	spin_unlock(&ci->i_ceph_lock);
1125 do_sync_unlocked:
1126 	if (lock_snap_rwsem)
1127 		up_read(&mdsc->snap_rwsem);
1128 
1129 	/* security module set xattr while filling trace */
1130 	if (current->journal_info) {
1131 		pr_warn_ratelimited("sync setxattr %p "
1132 				    "during filling trace\n", inode);
1133 		err = -EBUSY;
1134 	} else {
1135 		err = ceph_sync_setxattr(inode, name, value, size, flags);
1136 		if (err >= 0 && check_realm) {
1137 			/* check if snaprealm was created for quota inode */
1138 			spin_lock(&ci->i_ceph_lock);
1139 			if ((ci->i_max_files || ci->i_max_bytes) &&
1140 			    !(ci->i_snap_realm &&
1141 			      ci->i_snap_realm->ino == ci->i_vino.ino))
1142 				err = -EOPNOTSUPP;
1143 			spin_unlock(&ci->i_ceph_lock);
1144 		}
1145 	}
1146 out:
1147 	ceph_free_cap_flush(prealloc_cf);
1148 	kfree(newname);
1149 	kfree(newval);
1150 	kfree(xattr);
1151 	return err;
1152 }
1153 
1154 static int ceph_get_xattr_handler(const struct xattr_handler *handler,
1155 				  struct dentry *dentry, struct inode *inode,
1156 				  const char *name, void *value, size_t size)
1157 {
1158 	if (!ceph_is_valid_xattr(name))
1159 		return -EOPNOTSUPP;
1160 	return __ceph_getxattr(inode, name, value, size);
1161 }
1162 
1163 static int ceph_set_xattr_handler(const struct xattr_handler *handler,
1164 				  struct dentry *unused, struct inode *inode,
1165 				  const char *name, const void *value,
1166 				  size_t size, int flags)
1167 {
1168 	if (!ceph_is_valid_xattr(name))
1169 		return -EOPNOTSUPP;
1170 	return __ceph_setxattr(inode, name, value, size, flags);
1171 }
1172 
1173 static const struct xattr_handler ceph_other_xattr_handler = {
1174 	.prefix = "",  /* match any name => handlers called with full name */
1175 	.get = ceph_get_xattr_handler,
1176 	.set = ceph_set_xattr_handler,
1177 };
1178 
1179 #ifdef CONFIG_SECURITY
1180 bool ceph_security_xattr_wanted(struct inode *in)
1181 {
1182 	return in->i_security != NULL;
1183 }
1184 
1185 bool ceph_security_xattr_deadlock(struct inode *in)
1186 {
1187 	struct ceph_inode_info *ci;
1188 	bool ret;
1189 	if (!in->i_security)
1190 		return false;
1191 	ci = ceph_inode(in);
1192 	spin_lock(&ci->i_ceph_lock);
1193 	ret = !(ci->i_ceph_flags & CEPH_I_SEC_INITED) &&
1194 	      !(ci->i_xattrs.version > 0 &&
1195 		__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 0));
1196 	spin_unlock(&ci->i_ceph_lock);
1197 	return ret;
1198 }
1199 
1200 #ifdef CONFIG_CEPH_FS_SECURITY_LABEL
1201 int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
1202 			   struct ceph_acl_sec_ctx *as_ctx)
1203 {
1204 	struct ceph_pagelist *pagelist = as_ctx->pagelist;
1205 	const char *name;
1206 	size_t name_len;
1207 	int err;
1208 
1209 	err = security_dentry_init_security(dentry, mode, &dentry->d_name,
1210 					    &as_ctx->sec_ctx,
1211 					    &as_ctx->sec_ctxlen);
1212 	if (err < 0) {
1213 		WARN_ON_ONCE(err != -EOPNOTSUPP);
1214 		err = 0; /* do nothing */
1215 		goto out;
1216 	}
1217 
1218 	err = -ENOMEM;
1219 	if (!pagelist) {
1220 		pagelist = ceph_pagelist_alloc(GFP_KERNEL);
1221 		if (!pagelist)
1222 			goto out;
1223 		err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
1224 		if (err)
1225 			goto out;
1226 		ceph_pagelist_encode_32(pagelist, 1);
1227 	}
1228 
1229 	/*
1230 	 * FIXME: Make security_dentry_init_security() generic. Currently
1231 	 * It only supports single security module and only selinux has
1232 	 * dentry_init_security hook.
1233 	 */
1234 	name = XATTR_NAME_SELINUX;
1235 	name_len = strlen(name);
1236 	err = ceph_pagelist_reserve(pagelist,
1237 				    4 * 2 + name_len + as_ctx->sec_ctxlen);
1238 	if (err)
1239 		goto out;
1240 
1241 	if (as_ctx->pagelist) {
1242 		/* update count of KV pairs */
1243 		BUG_ON(pagelist->length <= sizeof(__le32));
1244 		if (list_is_singular(&pagelist->head)) {
1245 			le32_add_cpu((__le32*)pagelist->mapped_tail, 1);
1246 		} else {
1247 			struct page *page = list_first_entry(&pagelist->head,
1248 							     struct page, lru);
1249 			void *addr = kmap_atomic(page);
1250 			le32_add_cpu((__le32*)addr, 1);
1251 			kunmap_atomic(addr);
1252 		}
1253 	} else {
1254 		as_ctx->pagelist = pagelist;
1255 	}
1256 
1257 	ceph_pagelist_encode_32(pagelist, name_len);
1258 	ceph_pagelist_append(pagelist, name, name_len);
1259 
1260 	ceph_pagelist_encode_32(pagelist, as_ctx->sec_ctxlen);
1261 	ceph_pagelist_append(pagelist, as_ctx->sec_ctx, as_ctx->sec_ctxlen);
1262 
1263 	err = 0;
1264 out:
1265 	if (pagelist && !as_ctx->pagelist)
1266 		ceph_pagelist_release(pagelist);
1267 	return err;
1268 }
1269 #endif /* CONFIG_CEPH_FS_SECURITY_LABEL */
1270 #endif /* CONFIG_SECURITY */
1271 
1272 void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx)
1273 {
1274 #ifdef CONFIG_CEPH_FS_POSIX_ACL
1275 	posix_acl_release(as_ctx->acl);
1276 	posix_acl_release(as_ctx->default_acl);
1277 #endif
1278 #ifdef CONFIG_CEPH_FS_SECURITY_LABEL
1279 	security_release_secctx(as_ctx->sec_ctx, as_ctx->sec_ctxlen);
1280 #endif
1281 	if (as_ctx->pagelist)
1282 		ceph_pagelist_release(as_ctx->pagelist);
1283 }
1284 
1285 /*
1286  * List of handlers for synthetic system.* attributes. Other
1287  * attributes are handled directly.
1288  */
1289 const struct xattr_handler *ceph_xattr_handlers[] = {
1290 #ifdef CONFIG_CEPH_FS_POSIX_ACL
1291 	&posix_acl_access_xattr_handler,
1292 	&posix_acl_default_xattr_handler,
1293 #endif
1294 	&ceph_other_xattr_handler,
1295 	NULL,
1296 };
1297