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
ceph_adjust_quota_realms_count(struct inode * inode,bool inc)13 void ceph_adjust_quota_realms_count(struct inode *inode, bool inc)
14 {
15 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
16 if (inc)
17 atomic64_inc(&mdsc->quotarealms_count);
18 else
19 atomic64_dec(&mdsc->quotarealms_count);
20 }
21
ceph_has_realms_with_quotas(struct inode * inode)22 static inline bool ceph_has_realms_with_quotas(struct inode *inode)
23 {
24 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
25 struct super_block *sb = mdsc->fsc->sb;
26
27 if (atomic64_read(&mdsc->quotarealms_count) > 0)
28 return true;
29 /* if root is the real CephFS root, we don't have quota realms */
30 if (sb->s_root->d_inode &&
31 (sb->s_root->d_inode->i_ino == CEPH_INO_ROOT))
32 return false;
33 /* otherwise, we can't know for sure */
34 return true;
35 }
36
ceph_handle_quota(struct ceph_mds_client * mdsc,struct ceph_mds_session * session,struct ceph_msg * msg)37 void ceph_handle_quota(struct ceph_mds_client *mdsc,
38 struct ceph_mds_session *session,
39 struct ceph_msg *msg)
40 {
41 struct super_block *sb = mdsc->fsc->sb;
42 struct ceph_mds_quota *h = msg->front.iov_base;
43 struct ceph_vino vino;
44 struct inode *inode;
45 struct ceph_inode_info *ci;
46
47 if (msg->front.iov_len < sizeof(*h)) {
48 pr_err("%s corrupt message mds%d len %d\n", __func__,
49 session->s_mds, (int)msg->front.iov_len);
50 ceph_msg_dump(msg);
51 return;
52 }
53
54 /* increment msg sequence number */
55 mutex_lock(&session->s_mutex);
56 session->s_seq++;
57 mutex_unlock(&session->s_mutex);
58
59 /* lookup inode */
60 vino.ino = le64_to_cpu(h->ino);
61 vino.snap = CEPH_NOSNAP;
62 inode = ceph_find_inode(sb, vino);
63 if (!inode) {
64 pr_warn("Failed to find inode %llu\n", vino.ino);
65 return;
66 }
67 ci = ceph_inode(inode);
68
69 spin_lock(&ci->i_ceph_lock);
70 ci->i_rbytes = le64_to_cpu(h->rbytes);
71 ci->i_rfiles = le64_to_cpu(h->rfiles);
72 ci->i_rsubdirs = le64_to_cpu(h->rsubdirs);
73 __ceph_update_quota(ci, le64_to_cpu(h->max_bytes),
74 le64_to_cpu(h->max_files));
75 spin_unlock(&ci->i_ceph_lock);
76
77 /* avoid calling iput_final() in dispatch thread */
78 ceph_async_iput(inode);
79 }
80
81 static struct ceph_quotarealm_inode *
find_quotarealm_inode(struct ceph_mds_client * mdsc,u64 ino)82 find_quotarealm_inode(struct ceph_mds_client *mdsc, u64 ino)
83 {
84 struct ceph_quotarealm_inode *qri = NULL;
85 struct rb_node **node, *parent = NULL;
86
87 mutex_lock(&mdsc->quotarealms_inodes_mutex);
88 node = &(mdsc->quotarealms_inodes.rb_node);
89 while (*node) {
90 parent = *node;
91 qri = container_of(*node, struct ceph_quotarealm_inode, node);
92
93 if (ino < qri->ino)
94 node = &((*node)->rb_left);
95 else if (ino > qri->ino)
96 node = &((*node)->rb_right);
97 else
98 break;
99 }
100 if (!qri || (qri->ino != ino)) {
101 /* Not found, create a new one and insert it */
102 qri = kmalloc(sizeof(*qri), GFP_KERNEL);
103 if (qri) {
104 qri->ino = ino;
105 qri->inode = NULL;
106 qri->timeout = 0;
107 mutex_init(&qri->mutex);
108 rb_link_node(&qri->node, parent, node);
109 rb_insert_color(&qri->node, &mdsc->quotarealms_inodes);
110 } else
111 pr_warn("Failed to alloc quotarealms_inode\n");
112 }
113 mutex_unlock(&mdsc->quotarealms_inodes_mutex);
114
115 return qri;
116 }
117
118 /*
119 * This function will try to lookup a realm inode which isn't visible in the
120 * filesystem mountpoint. A list of these kind of inodes (not visible) is
121 * maintained in the mdsc and freed only when the filesystem is umounted.
122 *
123 * Note that these inodes are kept in this list even if the lookup fails, which
124 * allows to prevent useless lookup requests.
125 */
lookup_quotarealm_inode(struct ceph_mds_client * mdsc,struct super_block * sb,struct ceph_snap_realm * realm)126 static struct inode *lookup_quotarealm_inode(struct ceph_mds_client *mdsc,
127 struct super_block *sb,
128 struct ceph_snap_realm *realm)
129 {
130 struct ceph_quotarealm_inode *qri;
131 struct inode *in;
132
133 qri = find_quotarealm_inode(mdsc, realm->ino);
134 if (!qri)
135 return NULL;
136
137 mutex_lock(&qri->mutex);
138 if (qri->inode && ceph_is_any_caps(qri->inode)) {
139 /* A request has already returned the inode */
140 mutex_unlock(&qri->mutex);
141 return qri->inode;
142 }
143 /* Check if this inode lookup has failed recently */
144 if (qri->timeout &&
145 time_before_eq(jiffies, qri->timeout)) {
146 mutex_unlock(&qri->mutex);
147 return NULL;
148 }
149 if (qri->inode) {
150 /* get caps */
151 int ret = __ceph_do_getattr(qri->inode, NULL,
152 CEPH_STAT_CAP_INODE, true);
153 if (ret >= 0)
154 in = qri->inode;
155 else
156 in = ERR_PTR(ret);
157 } else {
158 in = ceph_lookup_inode(sb, realm->ino);
159 }
160
161 if (IS_ERR(in)) {
162 pr_warn("Can't lookup inode %llx (err: %ld)\n",
163 realm->ino, PTR_ERR(in));
164 qri->timeout = jiffies + msecs_to_jiffies(60 * 1000); /* XXX */
165 } else {
166 qri->timeout = 0;
167 qri->inode = in;
168 }
169 mutex_unlock(&qri->mutex);
170
171 return in;
172 }
173
ceph_cleanup_quotarealms_inodes(struct ceph_mds_client * mdsc)174 void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc)
175 {
176 struct ceph_quotarealm_inode *qri;
177 struct rb_node *node;
178
179 /*
180 * It should now be safe to clean quotarealms_inode tree without holding
181 * mdsc->quotarealms_inodes_mutex...
182 */
183 mutex_lock(&mdsc->quotarealms_inodes_mutex);
184 while (!RB_EMPTY_ROOT(&mdsc->quotarealms_inodes)) {
185 node = rb_first(&mdsc->quotarealms_inodes);
186 qri = rb_entry(node, struct ceph_quotarealm_inode, node);
187 rb_erase(node, &mdsc->quotarealms_inodes);
188 iput(qri->inode);
189 kfree(qri);
190 }
191 mutex_unlock(&mdsc->quotarealms_inodes_mutex);
192 }
193
194 /*
195 * This function walks through the snaprealm for an inode and returns the
196 * ceph_snap_realm for the first snaprealm that has quotas set (either max_files
197 * or max_bytes). If the root is reached, return the root ceph_snap_realm
198 * instead.
199 *
200 * Note that the caller is responsible for calling ceph_put_snap_realm() on the
201 * returned realm.
202 *
203 * Callers of this function need to hold mdsc->snap_rwsem. However, if there's
204 * a need to do an inode lookup, this rwsem will be temporarily dropped. Hence
205 * the 'retry' argument: if rwsem needs to be dropped and 'retry' is 'false'
206 * this function will return -EAGAIN; otherwise, the snaprealms walk-through
207 * will be restarted.
208 */
get_quota_realm(struct ceph_mds_client * mdsc,struct inode * inode,bool retry)209 static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc,
210 struct inode *inode, bool retry)
211 {
212 struct ceph_inode_info *ci = NULL;
213 struct ceph_snap_realm *realm, *next;
214 struct inode *in;
215 bool has_quota;
216
217 if (ceph_snap(inode) != CEPH_NOSNAP)
218 return NULL;
219
220 restart:
221 realm = ceph_inode(inode)->i_snap_realm;
222 if (realm)
223 ceph_get_snap_realm(mdsc, realm);
224 else
225 pr_err_ratelimited("get_quota_realm: ino (%llx.%llx) "
226 "null i_snap_realm\n", ceph_vinop(inode));
227 while (realm) {
228 bool has_inode;
229
230 spin_lock(&realm->inodes_with_caps_lock);
231 has_inode = realm->inode;
232 in = has_inode ? igrab(realm->inode) : NULL;
233 spin_unlock(&realm->inodes_with_caps_lock);
234 if (has_inode && !in)
235 break;
236 if (!in) {
237 up_read(&mdsc->snap_rwsem);
238 in = lookup_quotarealm_inode(mdsc, inode->i_sb, realm);
239 down_read(&mdsc->snap_rwsem);
240 if (IS_ERR_OR_NULL(in))
241 break;
242 ceph_put_snap_realm(mdsc, realm);
243 if (!retry)
244 return ERR_PTR(-EAGAIN);
245 goto restart;
246 }
247
248 ci = ceph_inode(in);
249 has_quota = __ceph_has_any_quota(ci);
250 /* avoid calling iput_final() while holding mdsc->snap_rwsem */
251 ceph_async_iput(in);
252
253 next = realm->parent;
254 if (has_quota || !next)
255 return realm;
256
257 ceph_get_snap_realm(mdsc, next);
258 ceph_put_snap_realm(mdsc, realm);
259 realm = next;
260 }
261 if (realm)
262 ceph_put_snap_realm(mdsc, realm);
263
264 return NULL;
265 }
266
ceph_quota_is_same_realm(struct inode * old,struct inode * new)267 bool ceph_quota_is_same_realm(struct inode *old, struct inode *new)
268 {
269 struct ceph_mds_client *mdsc = ceph_inode_to_client(old)->mdsc;
270 struct ceph_snap_realm *old_realm, *new_realm;
271 bool is_same;
272
273 restart:
274 /*
275 * We need to lookup 2 quota realms atomically, i.e. with snap_rwsem.
276 * However, get_quota_realm may drop it temporarily. By setting the
277 * 'retry' parameter to 'false', we'll get -EAGAIN if the rwsem was
278 * dropped and we can then restart the whole operation.
279 */
280 down_read(&mdsc->snap_rwsem);
281 old_realm = get_quota_realm(mdsc, old, true);
282 new_realm = get_quota_realm(mdsc, new, false);
283 if (PTR_ERR(new_realm) == -EAGAIN) {
284 up_read(&mdsc->snap_rwsem);
285 if (old_realm)
286 ceph_put_snap_realm(mdsc, old_realm);
287 goto restart;
288 }
289 is_same = (old_realm == new_realm);
290 up_read(&mdsc->snap_rwsem);
291
292 if (old_realm)
293 ceph_put_snap_realm(mdsc, old_realm);
294 if (new_realm)
295 ceph_put_snap_realm(mdsc, new_realm);
296
297 return is_same;
298 }
299
300 enum quota_check_op {
301 QUOTA_CHECK_MAX_FILES_OP, /* check quota max_files limit */
302 QUOTA_CHECK_MAX_BYTES_OP, /* check quota max_files limit */
303 QUOTA_CHECK_MAX_BYTES_APPROACHING_OP /* check if quota max_files
304 limit is approaching */
305 };
306
307 /*
308 * check_quota_exceeded() will walk up the snaprealm hierarchy and, for each
309 * realm, it will execute quota check operation defined by the 'op' parameter.
310 * The snaprealm walk is interrupted if the quota check detects that the quota
311 * is exceeded or if the root inode is reached.
312 */
check_quota_exceeded(struct inode * inode,enum quota_check_op op,loff_t delta)313 static bool check_quota_exceeded(struct inode *inode, enum quota_check_op op,
314 loff_t delta)
315 {
316 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
317 struct ceph_inode_info *ci;
318 struct ceph_snap_realm *realm, *next;
319 struct inode *in;
320 u64 max, rvalue;
321 bool exceeded = false;
322
323 if (ceph_snap(inode) != CEPH_NOSNAP)
324 return false;
325
326 down_read(&mdsc->snap_rwsem);
327 restart:
328 realm = ceph_inode(inode)->i_snap_realm;
329 if (realm)
330 ceph_get_snap_realm(mdsc, realm);
331 else
332 pr_err_ratelimited("check_quota_exceeded: ino (%llx.%llx) "
333 "null i_snap_realm\n", ceph_vinop(inode));
334 while (realm) {
335 bool has_inode;
336
337 spin_lock(&realm->inodes_with_caps_lock);
338 has_inode = realm->inode;
339 in = has_inode ? igrab(realm->inode) : NULL;
340 spin_unlock(&realm->inodes_with_caps_lock);
341 if (has_inode && !in)
342 break;
343 if (!in) {
344 up_read(&mdsc->snap_rwsem);
345 in = lookup_quotarealm_inode(mdsc, inode->i_sb, realm);
346 down_read(&mdsc->snap_rwsem);
347 if (IS_ERR_OR_NULL(in))
348 break;
349 ceph_put_snap_realm(mdsc, realm);
350 goto restart;
351 }
352 ci = ceph_inode(in);
353 spin_lock(&ci->i_ceph_lock);
354 if (op == QUOTA_CHECK_MAX_FILES_OP) {
355 max = ci->i_max_files;
356 rvalue = ci->i_rfiles + ci->i_rsubdirs;
357 } else {
358 max = ci->i_max_bytes;
359 rvalue = ci->i_rbytes;
360 }
361 spin_unlock(&ci->i_ceph_lock);
362 switch (op) {
363 case QUOTA_CHECK_MAX_FILES_OP:
364 exceeded = (max && (rvalue >= max));
365 break;
366 case QUOTA_CHECK_MAX_BYTES_OP:
367 exceeded = (max && (rvalue + delta > max));
368 break;
369 case QUOTA_CHECK_MAX_BYTES_APPROACHING_OP:
370 if (max) {
371 if (rvalue >= max)
372 exceeded = true;
373 else {
374 /*
375 * when we're writing more that 1/16th
376 * of the available space
377 */
378 exceeded =
379 (((max - rvalue) >> 4) < delta);
380 }
381 }
382 break;
383 default:
384 /* Shouldn't happen */
385 pr_warn("Invalid quota check op (%d)\n", op);
386 exceeded = true; /* Just break the loop */
387 }
388 /* avoid calling iput_final() while holding mdsc->snap_rwsem */
389 ceph_async_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 */
ceph_quota_is_max_files_exceeded(struct inode * inode)413 bool 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, 0);
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 */
ceph_quota_is_max_bytes_exceeded(struct inode * inode,loff_t newsize)431 bool 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 */
ceph_quota_is_max_bytes_approaching(struct inode * inode,loff_t newsize)453 bool 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 */
ceph_quota_update_statfs(struct ceph_fs_client * fsc,struct kstatfs * buf)478 bool 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), true);
489 up_read(&mdsc->snap_rwsem);
490 if (!realm)
491 return false;
492
493 spin_lock(&realm->inodes_with_caps_lock);
494 in = realm->inode ? igrab(realm->inode) : NULL;
495 spin_unlock(&realm->inodes_with_caps_lock);
496 if (in) {
497 ci = ceph_inode(in);
498 spin_lock(&ci->i_ceph_lock);
499 if (ci->i_max_bytes) {
500 total = ci->i_max_bytes >> CEPH_BLOCK_SHIFT;
501 used = ci->i_rbytes >> CEPH_BLOCK_SHIFT;
502 /* It is possible for a quota to be exceeded.
503 * Report 'zero' in that case
504 */
505 free = total > used ? total - used : 0;
506 }
507 spin_unlock(&ci->i_ceph_lock);
508 if (total) {
509 buf->f_blocks = total;
510 buf->f_bfree = free;
511 buf->f_bavail = free;
512 is_updated = true;
513 }
514 iput(in);
515 }
516 ceph_put_snap_realm(mdsc, realm);
517
518 return is_updated;
519 }
520
521