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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * quota.c - CephFS quota
4 *
5 * Copyright (C) 2017-2018 SUSE
6 */
7
8#include <linux/statfs.h>
9
10#include "super.h"
11#include "mds_client.h"
12
13void ceph_adjust_quota_realms_count(struct inode *inode, bool inc)
14{
15 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
16 if (inc)
17 atomic64_inc(&mdsc->quotarealms_count);
18 else
19 atomic64_dec(&mdsc->quotarealms_count);
20}
21
22static inline bool ceph_has_realms_with_quotas(struct inode *inode)
23{
24 struct super_block *sb = inode->i_sb;
25 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(sb);
26 struct inode *root = d_inode(sb->s_root);
27
28 if (atomic64_read(&mdsc->quotarealms_count) > 0)
29 return true;
30 /* if root is the real CephFS root, we don't have quota realms */
31 if (root && ceph_ino(root) == CEPH_INO_ROOT)
32 return false;
33 /* MDS stray dirs have no quota realms */
34 if (ceph_vino_is_reserved(ceph_inode(inode)->i_vino))
35 return false;
36 /* otherwise, we can't know for sure */
37 return true;
38}
39
40void ceph_handle_quota(struct ceph_mds_client *mdsc,
41 struct ceph_mds_session *session,
42 struct ceph_msg *msg)
43{
44 struct super_block *sb = mdsc->fsc->sb;
45 struct ceph_mds_quota *h = msg->front.iov_base;
46 struct ceph_vino vino;
47 struct inode *inode;
48 struct ceph_inode_info *ci;
49
50 if (msg->front.iov_len < sizeof(*h)) {
51 pr_err("%s corrupt message mds%d len %d\n", __func__,
52 session->s_mds, (int)msg->front.iov_len);
53 ceph_msg_dump(msg);
54 return;
55 }
56
57 /* increment msg sequence number */
58 mutex_lock(&session->s_mutex);
59 inc_session_sequence(session);
60 mutex_unlock(&session->s_mutex);
61
62 /* lookup inode */
63 vino.ino = le64_to_cpu(h->ino);
64 vino.snap = CEPH_NOSNAP;
65 inode = ceph_find_inode(sb, vino);
66 if (!inode) {
67 pr_warn("Failed to find inode %llu\n", vino.ino);
68 return;
69 }
70 ci = ceph_inode(inode);
71
72 spin_lock(&ci->i_ceph_lock);
73 ci->i_rbytes = le64_to_cpu(h->rbytes);
74 ci->i_rfiles = le64_to_cpu(h->rfiles);
75 ci->i_rsubdirs = le64_to_cpu(h->rsubdirs);
76 __ceph_update_quota(ci, le64_to_cpu(h->max_bytes),
77 le64_to_cpu(h->max_files));
78 spin_unlock(&ci->i_ceph_lock);
79
80 iput(inode);
81}
82
83static struct ceph_quotarealm_inode *
84find_quotarealm_inode(struct ceph_mds_client *mdsc, u64 ino)
85{
86 struct ceph_quotarealm_inode *qri = NULL;
87 struct rb_node **node, *parent = NULL;
88
89 mutex_lock(&mdsc->quotarealms_inodes_mutex);
90 node = &(mdsc->quotarealms_inodes.rb_node);
91 while (*node) {
92 parent = *node;
93 qri = container_of(*node, struct ceph_quotarealm_inode, node);
94
95 if (ino < qri->ino)
96 node = &((*node)->rb_left);
97 else if (ino > qri->ino)
98 node = &((*node)->rb_right);
99 else
100 break;
101 }
102 if (!qri || (qri->ino != ino)) {
103 /* Not found, create a new one and insert it */
104 qri = kmalloc(sizeof(*qri), GFP_KERNEL);
105 if (qri) {
106 qri->ino = ino;
107 qri->inode = NULL;
108 qri->timeout = 0;
109 mutex_init(&qri->mutex);
110 rb_link_node(&qri->node, parent, node);
111 rb_insert_color(&qri->node, &mdsc->quotarealms_inodes);
112 } else
113 pr_warn("Failed to alloc quotarealms_inode\n");
114 }
115 mutex_unlock(&mdsc->quotarealms_inodes_mutex);
116
117 return qri;
118}
119
120/*
121 * This function will try to lookup a realm inode which isn't visible in the
122 * filesystem mountpoint. A list of these kind of inodes (not visible) is
123 * maintained in the mdsc and freed only when the filesystem is umounted.
124 *
125 * Note that these inodes are kept in this list even if the lookup fails, which
126 * allows to prevent useless lookup requests.
127 */
128static struct inode *lookup_quotarealm_inode(struct ceph_mds_client *mdsc,
129 struct super_block *sb,
130 struct ceph_snap_realm *realm)
131{
132 struct ceph_quotarealm_inode *qri;
133 struct inode *in;
134
135 qri = find_quotarealm_inode(mdsc, realm->ino);
136 if (!qri)
137 return NULL;
138
139 mutex_lock(&qri->mutex);
140 if (qri->inode && ceph_is_any_caps(qri->inode)) {
141 /* A request has already returned the inode */
142 mutex_unlock(&qri->mutex);
143 return qri->inode;
144 }
145 /* Check if this inode lookup has failed recently */
146 if (qri->timeout &&
147 time_before_eq(jiffies, qri->timeout)) {
148 mutex_unlock(&qri->mutex);
149 return NULL;
150 }
151 if (qri->inode) {
152 /* get caps */
153 int ret = __ceph_do_getattr(qri->inode, NULL,
154 CEPH_STAT_CAP_INODE, true);
155 if (ret >= 0)
156 in = qri->inode;
157 else
158 in = ERR_PTR(ret);
159 } else {
160 in = ceph_lookup_inode(sb, realm->ino);
161 }
162
163 if (IS_ERR(in)) {
164 dout("Can't lookup inode %llx (err: %ld)\n",
165 realm->ino, PTR_ERR(in));
166 qri->timeout = jiffies + msecs_to_jiffies(60 * 1000); /* XXX */
167 } else {
168 qri->timeout = 0;
169 qri->inode = in;
170 }
171 mutex_unlock(&qri->mutex);
172
173 return in;
174}
175
176void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc)
177{
178 struct ceph_quotarealm_inode *qri;
179 struct rb_node *node;
180
181 /*
182 * It should now be safe to clean quotarealms_inode tree without holding
183 * mdsc->quotarealms_inodes_mutex...
184 */
185 mutex_lock(&mdsc->quotarealms_inodes_mutex);
186 while (!RB_EMPTY_ROOT(&mdsc->quotarealms_inodes)) {
187 node = rb_first(&mdsc->quotarealms_inodes);
188 qri = rb_entry(node, struct ceph_quotarealm_inode, node);
189 rb_erase(node, &mdsc->quotarealms_inodes);
190 iput(qri->inode);
191 kfree(qri);
192 }
193 mutex_unlock(&mdsc->quotarealms_inodes_mutex);
194}
195
196/*
197 * This function walks through the snaprealm for an inode and returns the
198 * ceph_snap_realm for the first snaprealm that has quotas set (max_files,
199 * max_bytes, or any, depending on the 'which_quota' argument). If the root is
200 * reached, return the root ceph_snap_realm instead.
201 *
202 * Note that the caller is responsible for calling ceph_put_snap_realm() on the
203 * returned realm.
204 *
205 * Callers of this function need to hold mdsc->snap_rwsem. However, if there's
206 * a need to do an inode lookup, this rwsem will be temporarily dropped. Hence
207 * the 'retry' argument: if rwsem needs to be dropped and 'retry' is 'false'
208 * this function will return -EAGAIN; otherwise, the snaprealms walk-through
209 * will be restarted.
210 */
211static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc,
212 struct inode *inode,
213 enum quota_get_realm which_quota,
214 bool retry)
215{
216 struct ceph_inode_info *ci = NULL;
217 struct ceph_snap_realm *realm, *next;
218 struct inode *in;
219 bool has_quota;
220
221 if (ceph_snap(inode) != CEPH_NOSNAP)
222 return NULL;
223
224restart:
225 realm = ceph_inode(inode)->i_snap_realm;
226 if (realm)
227 ceph_get_snap_realm(mdsc, realm);
228 else
229 pr_err_ratelimited("get_quota_realm: ino (%llx.%llx) "
230 "null i_snap_realm\n", ceph_vinop(inode));
231 while (realm) {
232 bool has_inode;
233
234 spin_lock(&realm->inodes_with_caps_lock);
235 has_inode = realm->inode;
236 in = has_inode ? igrab(realm->inode) : NULL;
237 spin_unlock(&realm->inodes_with_caps_lock);
238 if (has_inode && !in)
239 break;
240 if (!in) {
241 up_read(&mdsc->snap_rwsem);
242 in = lookup_quotarealm_inode(mdsc, inode->i_sb, realm);
243 down_read(&mdsc->snap_rwsem);
244 if (IS_ERR_OR_NULL(in))
245 break;
246 ceph_put_snap_realm(mdsc, realm);
247 if (!retry)
248 return ERR_PTR(-EAGAIN);
249 goto restart;
250 }
251
252 ci = ceph_inode(in);
253 has_quota = __ceph_has_quota(ci, which_quota);
254 iput(in);
255
256 next = realm->parent;
257 if (has_quota || !next)
258 return realm;
259
260 ceph_get_snap_realm(mdsc, next);
261 ceph_put_snap_realm(mdsc, realm);
262 realm = next;
263 }
264 if (realm)
265 ceph_put_snap_realm(mdsc, realm);
266
267 return NULL;
268}
269
270bool ceph_quota_is_same_realm(struct inode *old, struct inode *new)
271{
272 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(old->i_sb);
273 struct ceph_snap_realm *old_realm, *new_realm;
274 bool is_same;
275
276restart:
277 /*
278 * We need to lookup 2 quota realms atomically, i.e. with snap_rwsem.
279 * However, get_quota_realm may drop it temporarily. By setting the
280 * 'retry' parameter to 'false', we'll get -EAGAIN if the rwsem was
281 * dropped and we can then restart the whole operation.
282 */
283 down_read(&mdsc->snap_rwsem);
284 old_realm = get_quota_realm(mdsc, old, QUOTA_GET_ANY, true);
285 new_realm = get_quota_realm(mdsc, new, QUOTA_GET_ANY, false);
286 if (PTR_ERR(new_realm) == -EAGAIN) {
287 up_read(&mdsc->snap_rwsem);
288 if (old_realm)
289 ceph_put_snap_realm(mdsc, old_realm);
290 goto restart;
291 }
292 is_same = (old_realm == new_realm);
293 up_read(&mdsc->snap_rwsem);
294
295 if (old_realm)
296 ceph_put_snap_realm(mdsc, old_realm);
297 if (new_realm)
298 ceph_put_snap_realm(mdsc, new_realm);
299
300 return is_same;
301}
302
303enum quota_check_op {
304 QUOTA_CHECK_MAX_FILES_OP, /* check quota max_files limit */
305 QUOTA_CHECK_MAX_BYTES_OP, /* check quota max_files limit */
306 QUOTA_CHECK_MAX_BYTES_APPROACHING_OP /* check if quota max_files
307 limit is approaching */
308};
309
310/*
311 * check_quota_exceeded() will walk up the snaprealm hierarchy and, for each
312 * realm, it will execute quota check operation defined by the 'op' parameter.
313 * The snaprealm walk is interrupted if the quota check detects that the quota
314 * is exceeded or if the root inode is reached.
315 */
316static bool check_quota_exceeded(struct inode *inode, enum quota_check_op op,
317 loff_t delta)
318{
319 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
320 struct ceph_inode_info *ci;
321 struct ceph_snap_realm *realm, *next;
322 struct inode *in;
323 u64 max, rvalue;
324 bool exceeded = false;
325
326 if (ceph_snap(inode) != CEPH_NOSNAP)
327 return false;
328
329 down_read(&mdsc->snap_rwsem);
330restart:
331 realm = ceph_inode(inode)->i_snap_realm;
332 if (realm)
333 ceph_get_snap_realm(mdsc, realm);
334 else
335 pr_err_ratelimited("check_quota_exceeded: ino (%llx.%llx) "
336 "null i_snap_realm\n", ceph_vinop(inode));
337 while (realm) {
338 bool has_inode;
339
340 spin_lock(&realm->inodes_with_caps_lock);
341 has_inode = realm->inode;
342 in = has_inode ? igrab(realm->inode) : NULL;
343 spin_unlock(&realm->inodes_with_caps_lock);
344 if (has_inode && !in)
345 break;
346 if (!in) {
347 up_read(&mdsc->snap_rwsem);
348 in = lookup_quotarealm_inode(mdsc, inode->i_sb, realm);
349 down_read(&mdsc->snap_rwsem);
350 if (IS_ERR_OR_NULL(in))
351 break;
352 ceph_put_snap_realm(mdsc, realm);
353 goto restart;
354 }
355 ci = ceph_inode(in);
356 spin_lock(&ci->i_ceph_lock);
357 if (op == QUOTA_CHECK_MAX_FILES_OP) {
358 max = ci->i_max_files;
359 rvalue = ci->i_rfiles + ci->i_rsubdirs;
360 } else {
361 max = ci->i_max_bytes;
362 rvalue = ci->i_rbytes;
363 }
364 spin_unlock(&ci->i_ceph_lock);
365 switch (op) {
366 case QUOTA_CHECK_MAX_FILES_OP:
367 case QUOTA_CHECK_MAX_BYTES_OP:
368 exceeded = (max && (rvalue + delta > max));
369 break;
370 case QUOTA_CHECK_MAX_BYTES_APPROACHING_OP:
371 if (max) {
372 if (rvalue >= max)
373 exceeded = true;
374 else {
375 /*
376 * when we're writing more that 1/16th
377 * of the available space
378 */
379 exceeded =
380 (((max - rvalue) >> 4) < delta);
381 }
382 }
383 break;
384 default:
385 /* Shouldn't happen */
386 pr_warn("Invalid quota check op (%d)\n", op);
387 exceeded = true; /* Just break the loop */
388 }
389 iput(in);
390
391 next = realm->parent;
392 if (exceeded || !next)
393 break;
394 ceph_get_snap_realm(mdsc, next);
395 ceph_put_snap_realm(mdsc, realm);
396 realm = next;
397 }
398 if (realm)
399 ceph_put_snap_realm(mdsc, realm);
400 up_read(&mdsc->snap_rwsem);
401
402 return exceeded;
403}
404
405/*
406 * ceph_quota_is_max_files_exceeded - check if we can create a new file
407 * @inode: directory where a new file is being created
408 *
409 * This functions returns true is max_files quota allows a new file to be
410 * created. It is necessary to walk through the snaprealm hierarchy (until the
411 * FS root) to check all realms with quotas set.
412 */
413bool ceph_quota_is_max_files_exceeded(struct inode *inode)
414{
415 if (!ceph_has_realms_with_quotas(inode))
416 return false;
417
418 WARN_ON(!S_ISDIR(inode->i_mode));
419
420 return check_quota_exceeded(inode, QUOTA_CHECK_MAX_FILES_OP, 1);
421}
422
423/*
424 * ceph_quota_is_max_bytes_exceeded - check if we can write to a file
425 * @inode: inode being written
426 * @newsize: new size if write succeeds
427 *
428 * This functions returns true is max_bytes quota allows a file size to reach
429 * @newsize; it returns false otherwise.
430 */
431bool ceph_quota_is_max_bytes_exceeded(struct inode *inode, loff_t newsize)
432{
433 loff_t size = i_size_read(inode);
434
435 if (!ceph_has_realms_with_quotas(inode))
436 return false;
437
438 /* return immediately if we're decreasing file size */
439 if (newsize <= size)
440 return false;
441
442 return check_quota_exceeded(inode, QUOTA_CHECK_MAX_BYTES_OP, (newsize - size));
443}
444
445/*
446 * ceph_quota_is_max_bytes_approaching - check if we're reaching max_bytes
447 * @inode: inode being written
448 * @newsize: new size if write succeeds
449 *
450 * This function returns true if the new file size @newsize will be consuming
451 * more than 1/16th of the available quota space; it returns false otherwise.
452 */
453bool ceph_quota_is_max_bytes_approaching(struct inode *inode, loff_t newsize)
454{
455 loff_t size = ceph_inode(inode)->i_reported_size;
456
457 if (!ceph_has_realms_with_quotas(inode))
458 return false;
459
460 /* return immediately if we're decreasing file size */
461 if (newsize <= size)
462 return false;
463
464 return check_quota_exceeded(inode, QUOTA_CHECK_MAX_BYTES_APPROACHING_OP,
465 (newsize - size));
466}
467
468/*
469 * ceph_quota_update_statfs - if root has quota update statfs with quota status
470 * @fsc: filesystem client instance
471 * @buf: statfs to update
472 *
473 * If the mounted filesystem root has max_bytes quota set, update the filesystem
474 * statistics with the quota status.
475 *
476 * This function returns true if the stats have been updated, false otherwise.
477 */
478bool ceph_quota_update_statfs(struct ceph_fs_client *fsc, struct kstatfs *buf)
479{
480 struct ceph_mds_client *mdsc = fsc->mdsc;
481 struct ceph_inode_info *ci;
482 struct ceph_snap_realm *realm;
483 struct inode *in;
484 u64 total = 0, used, free;
485 bool is_updated = false;
486
487 down_read(&mdsc->snap_rwsem);
488 realm = get_quota_realm(mdsc, d_inode(fsc->sb->s_root),
489 QUOTA_GET_MAX_BYTES, true);
490 up_read(&mdsc->snap_rwsem);
491 if (!realm)
492 return false;
493
494 spin_lock(&realm->inodes_with_caps_lock);
495 in = realm->inode ? igrab(realm->inode) : NULL;
496 spin_unlock(&realm->inodes_with_caps_lock);
497 if (in) {
498 ci = ceph_inode(in);
499 spin_lock(&ci->i_ceph_lock);
500 if (ci->i_max_bytes) {
501 total = ci->i_max_bytes >> CEPH_BLOCK_SHIFT;
502 used = ci->i_rbytes >> CEPH_BLOCK_SHIFT;
503 /* For quota size less than 4MB, use 4KB block size */
504 if (!total) {
505 total = ci->i_max_bytes >> CEPH_4K_BLOCK_SHIFT;
506 used = ci->i_rbytes >> CEPH_4K_BLOCK_SHIFT;
507 buf->f_frsize = 1 << CEPH_4K_BLOCK_SHIFT;
508 }
509 /* It is possible for a quota to be exceeded.
510 * Report 'zero' in that case
511 */
512 free = total > used ? total - used : 0;
513 /* For quota size less than 4KB, report the
514 * total=used=4KB,free=0 when quota is full
515 * and total=free=4KB, used=0 otherwise */
516 if (!total) {
517 total = 1;
518 free = ci->i_max_bytes > ci->i_rbytes ? 1 : 0;
519 buf->f_frsize = 1 << CEPH_4K_BLOCK_SHIFT;
520 }
521 }
522 spin_unlock(&ci->i_ceph_lock);
523 if (total) {
524 buf->f_blocks = total;
525 buf->f_bfree = free;
526 buf->f_bavail = free;
527 is_updated = true;
528 }
529 iput(in);
530 }
531 ceph_put_snap_realm(mdsc, realm);
532
533 return is_updated;
534}
535