1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ceph/ceph_debug.h>
3
4 #include <linux/exportfs.h>
5 #include <linux/slab.h>
6 #include <asm/unaligned.h>
7
8 #include "super.h"
9 #include "mds_client.h"
10
11 /*
12 * Basic fh
13 */
14 struct ceph_nfs_fh {
15 u64 ino;
16 } __attribute__ ((packed));
17
18 /*
19 * Larger fh that includes parent ino.
20 */
21 struct ceph_nfs_confh {
22 u64 ino, parent_ino;
23 } __attribute__ ((packed));
24
25 /*
26 * fh for snapped inode
27 */
28 struct ceph_nfs_snapfh {
29 u64 ino;
30 u64 snapid;
31 u64 parent_ino;
32 u32 hash;
33 } __attribute__ ((packed));
34
ceph_encode_snapfh(struct inode * inode,u32 * rawfh,int * max_len,struct inode * parent_inode)35 static int ceph_encode_snapfh(struct inode *inode, u32 *rawfh, int *max_len,
36 struct inode *parent_inode)
37 {
38 static const int snap_handle_length =
39 sizeof(struct ceph_nfs_snapfh) >> 2;
40 struct ceph_nfs_snapfh *sfh = (void *)rawfh;
41 u64 snapid = ceph_snap(inode);
42 int ret;
43 bool no_parent = true;
44
45 if (*max_len < snap_handle_length) {
46 *max_len = snap_handle_length;
47 ret = FILEID_INVALID;
48 goto out;
49 }
50
51 ret = -EINVAL;
52 if (snapid != CEPH_SNAPDIR) {
53 struct inode *dir;
54 struct dentry *dentry = d_find_alias(inode);
55 if (!dentry)
56 goto out;
57
58 rcu_read_lock();
59 dir = d_inode_rcu(dentry->d_parent);
60 if (ceph_snap(dir) != CEPH_SNAPDIR) {
61 sfh->parent_ino = ceph_ino(dir);
62 sfh->hash = ceph_dentry_hash(dir, dentry);
63 no_parent = false;
64 }
65 rcu_read_unlock();
66 dput(dentry);
67 }
68
69 if (no_parent) {
70 if (!S_ISDIR(inode->i_mode))
71 goto out;
72 sfh->parent_ino = sfh->ino;
73 sfh->hash = 0;
74 }
75 sfh->ino = ceph_ino(inode);
76 sfh->snapid = snapid;
77
78 *max_len = snap_handle_length;
79 ret = FILEID_BTRFS_WITH_PARENT;
80 out:
81 dout("encode_snapfh %llx.%llx ret=%d\n", ceph_vinop(inode), ret);
82 return ret;
83 }
84
ceph_encode_fh(struct inode * inode,u32 * rawfh,int * max_len,struct inode * parent_inode)85 static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
86 struct inode *parent_inode)
87 {
88 static const int handle_length =
89 sizeof(struct ceph_nfs_fh) >> 2;
90 static const int connected_handle_length =
91 sizeof(struct ceph_nfs_confh) >> 2;
92 int type;
93
94 if (ceph_snap(inode) != CEPH_NOSNAP)
95 return ceph_encode_snapfh(inode, rawfh, max_len, parent_inode);
96
97 if (parent_inode && (*max_len < connected_handle_length)) {
98 *max_len = connected_handle_length;
99 return FILEID_INVALID;
100 } else if (*max_len < handle_length) {
101 *max_len = handle_length;
102 return FILEID_INVALID;
103 }
104
105 if (parent_inode) {
106 struct ceph_nfs_confh *cfh = (void *)rawfh;
107 dout("encode_fh %llx with parent %llx\n",
108 ceph_ino(inode), ceph_ino(parent_inode));
109 cfh->ino = ceph_ino(inode);
110 cfh->parent_ino = ceph_ino(parent_inode);
111 *max_len = connected_handle_length;
112 type = FILEID_INO32_GEN_PARENT;
113 } else {
114 struct ceph_nfs_fh *fh = (void *)rawfh;
115 dout("encode_fh %llx\n", ceph_ino(inode));
116 fh->ino = ceph_ino(inode);
117 *max_len = handle_length;
118 type = FILEID_INO32_GEN;
119 }
120 return type;
121 }
122
__lookup_inode(struct super_block * sb,u64 ino)123 static struct inode *__lookup_inode(struct super_block *sb, u64 ino)
124 {
125 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
126 struct inode *inode;
127 struct ceph_vino vino;
128 int err;
129
130 vino.ino = ino;
131 vino.snap = CEPH_NOSNAP;
132 inode = ceph_find_inode(sb, vino);
133 if (!inode) {
134 struct ceph_mds_request *req;
135 int mask;
136
137 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
138 USE_ANY_MDS);
139 if (IS_ERR(req))
140 return ERR_CAST(req);
141
142 mask = CEPH_STAT_CAP_INODE;
143 if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
144 mask |= CEPH_CAP_XATTR_SHARED;
145 req->r_args.lookupino.mask = cpu_to_le32(mask);
146
147 req->r_ino1 = vino;
148 req->r_num_caps = 1;
149 err = ceph_mdsc_do_request(mdsc, NULL, req);
150 inode = req->r_target_inode;
151 if (inode)
152 ihold(inode);
153 ceph_mdsc_put_request(req);
154 if (!inode)
155 return err < 0 ? ERR_PTR(err) : ERR_PTR(-ESTALE);
156 }
157 return inode;
158 }
159
ceph_lookup_inode(struct super_block * sb,u64 ino)160 struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino)
161 {
162 struct inode *inode = __lookup_inode(sb, ino);
163 if (IS_ERR(inode))
164 return inode;
165 if (inode->i_nlink == 0) {
166 iput(inode);
167 return ERR_PTR(-ESTALE);
168 }
169 return inode;
170 }
171
__fh_to_dentry(struct super_block * sb,u64 ino)172 static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
173 {
174 struct inode *inode = __lookup_inode(sb, ino);
175 int err;
176
177 if (IS_ERR(inode))
178 return ERR_CAST(inode);
179 /* We need LINK caps to reliably check i_nlink */
180 err = ceph_do_getattr(inode, CEPH_CAP_LINK_SHARED, false);
181 if (err) {
182 iput(inode);
183 return ERR_PTR(err);
184 }
185 /* -ESTALE if inode as been unlinked and no file is open */
186 if ((inode->i_nlink == 0) && (atomic_read(&inode->i_count) == 1)) {
187 iput(inode);
188 return ERR_PTR(-ESTALE);
189 }
190 return d_obtain_alias(inode);
191 }
192
__snapfh_to_dentry(struct super_block * sb,struct ceph_nfs_snapfh * sfh,bool want_parent)193 static struct dentry *__snapfh_to_dentry(struct super_block *sb,
194 struct ceph_nfs_snapfh *sfh,
195 bool want_parent)
196 {
197 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
198 struct ceph_mds_request *req;
199 struct inode *inode;
200 struct ceph_vino vino;
201 int mask;
202 int err;
203 bool unlinked = false;
204
205 if (want_parent) {
206 vino.ino = sfh->parent_ino;
207 if (sfh->snapid == CEPH_SNAPDIR)
208 vino.snap = CEPH_NOSNAP;
209 else if (sfh->ino == sfh->parent_ino)
210 vino.snap = CEPH_SNAPDIR;
211 else
212 vino.snap = sfh->snapid;
213 } else {
214 vino.ino = sfh->ino;
215 vino.snap = sfh->snapid;
216 }
217 inode = ceph_find_inode(sb, vino);
218 if (inode)
219 return d_obtain_alias(inode);
220
221 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
222 USE_ANY_MDS);
223 if (IS_ERR(req))
224 return ERR_CAST(req);
225
226 mask = CEPH_STAT_CAP_INODE;
227 if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
228 mask |= CEPH_CAP_XATTR_SHARED;
229 req->r_args.lookupino.mask = cpu_to_le32(mask);
230 if (vino.snap < CEPH_NOSNAP) {
231 req->r_args.lookupino.snapid = cpu_to_le64(vino.snap);
232 if (!want_parent && sfh->ino != sfh->parent_ino) {
233 req->r_args.lookupino.parent =
234 cpu_to_le64(sfh->parent_ino);
235 req->r_args.lookupino.hash =
236 cpu_to_le32(sfh->hash);
237 }
238 }
239
240 req->r_ino1 = vino;
241 req->r_num_caps = 1;
242 err = ceph_mdsc_do_request(mdsc, NULL, req);
243 inode = req->r_target_inode;
244 if (inode) {
245 if (vino.snap == CEPH_SNAPDIR) {
246 if (inode->i_nlink == 0)
247 unlinked = true;
248 inode = ceph_get_snapdir(inode);
249 } else if (ceph_snap(inode) == vino.snap) {
250 ihold(inode);
251 } else {
252 /* mds does not support lookup snapped inode */
253 err = -EOPNOTSUPP;
254 inode = NULL;
255 }
256 }
257 ceph_mdsc_put_request(req);
258
259 if (want_parent) {
260 dout("snapfh_to_parent %llx.%llx\n err=%d\n",
261 vino.ino, vino.snap, err);
262 } else {
263 dout("snapfh_to_dentry %llx.%llx parent %llx hash %x err=%d",
264 vino.ino, vino.snap, sfh->parent_ino, sfh->hash, err);
265 }
266 if (!inode)
267 return ERR_PTR(-ESTALE);
268 /* see comments in ceph_get_parent() */
269 return unlinked ? d_obtain_root(inode) : d_obtain_alias(inode);
270 }
271
272 /*
273 * convert regular fh to dentry
274 */
ceph_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)275 static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
276 struct fid *fid,
277 int fh_len, int fh_type)
278 {
279 struct ceph_nfs_fh *fh = (void *)fid->raw;
280
281 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
282 struct ceph_nfs_snapfh *sfh = (void *)fid->raw;
283 return __snapfh_to_dentry(sb, sfh, false);
284 }
285
286 if (fh_type != FILEID_INO32_GEN &&
287 fh_type != FILEID_INO32_GEN_PARENT)
288 return NULL;
289 if (fh_len < sizeof(*fh) / 4)
290 return NULL;
291
292 dout("fh_to_dentry %llx\n", fh->ino);
293 return __fh_to_dentry(sb, fh->ino);
294 }
295
__get_parent(struct super_block * sb,struct dentry * child,u64 ino)296 static struct dentry *__get_parent(struct super_block *sb,
297 struct dentry *child, u64 ino)
298 {
299 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
300 struct ceph_mds_request *req;
301 struct inode *inode;
302 int mask;
303 int err;
304
305 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
306 USE_ANY_MDS);
307 if (IS_ERR(req))
308 return ERR_CAST(req);
309
310 if (child) {
311 req->r_inode = d_inode(child);
312 ihold(d_inode(child));
313 } else {
314 req->r_ino1 = (struct ceph_vino) {
315 .ino = ino,
316 .snap = CEPH_NOSNAP,
317 };
318 }
319
320 mask = CEPH_STAT_CAP_INODE;
321 if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
322 mask |= CEPH_CAP_XATTR_SHARED;
323 req->r_args.getattr.mask = cpu_to_le32(mask);
324
325 req->r_num_caps = 1;
326 err = ceph_mdsc_do_request(mdsc, NULL, req);
327 if (err) {
328 ceph_mdsc_put_request(req);
329 return ERR_PTR(err);
330 }
331
332 inode = req->r_target_inode;
333 if (inode)
334 ihold(inode);
335 ceph_mdsc_put_request(req);
336 if (!inode)
337 return ERR_PTR(-ENOENT);
338
339 return d_obtain_alias(inode);
340 }
341
ceph_get_parent(struct dentry * child)342 static struct dentry *ceph_get_parent(struct dentry *child)
343 {
344 struct inode *inode = d_inode(child);
345 struct dentry *dn;
346
347 if (ceph_snap(inode) != CEPH_NOSNAP) {
348 struct inode* dir;
349 bool unlinked = false;
350 /* do not support non-directory */
351 if (!d_is_dir(child)) {
352 dn = ERR_PTR(-EINVAL);
353 goto out;
354 }
355 dir = __lookup_inode(inode->i_sb, ceph_ino(inode));
356 if (IS_ERR(dir)) {
357 dn = ERR_CAST(dir);
358 goto out;
359 }
360 /* There can be multiple paths to access snapped inode.
361 * For simplicity, treat snapdir of head inode as parent */
362 if (ceph_snap(inode) != CEPH_SNAPDIR) {
363 struct inode *snapdir = ceph_get_snapdir(dir);
364 if (dir->i_nlink == 0)
365 unlinked = true;
366 iput(dir);
367 if (IS_ERR(snapdir)) {
368 dn = ERR_CAST(snapdir);
369 goto out;
370 }
371 dir = snapdir;
372 }
373 /* If directory has already been deleted, futher get_parent
374 * will fail. Do not mark snapdir dentry as disconnected,
375 * this prevent exportfs from doing futher get_parent. */
376 if (unlinked)
377 dn = d_obtain_root(dir);
378 else
379 dn = d_obtain_alias(dir);
380 } else {
381 dn = __get_parent(child->d_sb, child, 0);
382 }
383 out:
384 dout("get_parent %p ino %llx.%llx err=%ld\n",
385 child, ceph_vinop(inode), (long)PTR_ERR_OR_ZERO(dn));
386 return dn;
387 }
388
389 /*
390 * convert regular fh to parent
391 */
ceph_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)392 static struct dentry *ceph_fh_to_parent(struct super_block *sb,
393 struct fid *fid,
394 int fh_len, int fh_type)
395 {
396 struct ceph_nfs_confh *cfh = (void *)fid->raw;
397 struct dentry *dentry;
398
399 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
400 struct ceph_nfs_snapfh *sfh = (void *)fid->raw;
401 return __snapfh_to_dentry(sb, sfh, true);
402 }
403
404 if (fh_type != FILEID_INO32_GEN_PARENT)
405 return NULL;
406 if (fh_len < sizeof(*cfh) / 4)
407 return NULL;
408
409 dout("fh_to_parent %llx\n", cfh->parent_ino);
410 dentry = __get_parent(sb, NULL, cfh->ino);
411 if (unlikely(dentry == ERR_PTR(-ENOENT)))
412 dentry = __fh_to_dentry(sb, cfh->parent_ino);
413 return dentry;
414 }
415
__get_snap_name(struct dentry * parent,char * name,struct dentry * child)416 static int __get_snap_name(struct dentry *parent, char *name,
417 struct dentry *child)
418 {
419 struct inode *inode = d_inode(child);
420 struct inode *dir = d_inode(parent);
421 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
422 struct ceph_mds_request *req = NULL;
423 char *last_name = NULL;
424 unsigned next_offset = 2;
425 int err = -EINVAL;
426
427 if (ceph_ino(inode) != ceph_ino(dir))
428 goto out;
429 if (ceph_snap(inode) == CEPH_SNAPDIR) {
430 if (ceph_snap(dir) == CEPH_NOSNAP) {
431 strcpy(name, fsc->mount_options->snapdir_name);
432 err = 0;
433 }
434 goto out;
435 }
436 if (ceph_snap(dir) != CEPH_SNAPDIR)
437 goto out;
438
439 while (1) {
440 struct ceph_mds_reply_info_parsed *rinfo;
441 struct ceph_mds_reply_dir_entry *rde;
442 int i;
443
444 req = ceph_mdsc_create_request(fsc->mdsc, CEPH_MDS_OP_LSSNAP,
445 USE_AUTH_MDS);
446 if (IS_ERR(req)) {
447 err = PTR_ERR(req);
448 req = NULL;
449 goto out;
450 }
451 err = ceph_alloc_readdir_reply_buffer(req, inode);
452 if (err)
453 goto out;
454
455 req->r_direct_mode = USE_AUTH_MDS;
456 req->r_readdir_offset = next_offset;
457 req->r_args.readdir.flags =
458 cpu_to_le16(CEPH_READDIR_REPLY_BITFLAGS);
459 if (last_name) {
460 req->r_path2 = last_name;
461 last_name = NULL;
462 }
463
464 req->r_inode = dir;
465 ihold(dir);
466 req->r_dentry = dget(parent);
467
468 inode_lock(dir);
469 err = ceph_mdsc_do_request(fsc->mdsc, NULL, req);
470 inode_unlock(dir);
471
472 if (err < 0)
473 goto out;
474
475 rinfo = &req->r_reply_info;
476 for (i = 0; i < rinfo->dir_nr; i++) {
477 rde = rinfo->dir_entries + i;
478 BUG_ON(!rde->inode.in);
479 if (ceph_snap(inode) ==
480 le64_to_cpu(rde->inode.in->snapid)) {
481 memcpy(name, rde->name, rde->name_len);
482 name[rde->name_len] = '\0';
483 err = 0;
484 goto out;
485 }
486 }
487
488 if (rinfo->dir_end)
489 break;
490
491 BUG_ON(rinfo->dir_nr <= 0);
492 rde = rinfo->dir_entries + (rinfo->dir_nr - 1);
493 next_offset += rinfo->dir_nr;
494 last_name = kstrndup(rde->name, rde->name_len, GFP_KERNEL);
495 if (!last_name) {
496 err = -ENOMEM;
497 goto out;
498 }
499
500 ceph_mdsc_put_request(req);
501 req = NULL;
502 }
503 err = -ENOENT;
504 out:
505 if (req)
506 ceph_mdsc_put_request(req);
507 kfree(last_name);
508 dout("get_snap_name %p ino %llx.%llx err=%d\n",
509 child, ceph_vinop(inode), err);
510 return err;
511 }
512
ceph_get_name(struct dentry * parent,char * name,struct dentry * child)513 static int ceph_get_name(struct dentry *parent, char *name,
514 struct dentry *child)
515 {
516 struct ceph_mds_client *mdsc;
517 struct ceph_mds_request *req;
518 struct inode *inode = d_inode(child);
519 int err;
520
521 if (ceph_snap(inode) != CEPH_NOSNAP)
522 return __get_snap_name(parent, name, child);
523
524 mdsc = ceph_inode_to_client(inode)->mdsc;
525 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
526 USE_ANY_MDS);
527 if (IS_ERR(req))
528 return PTR_ERR(req);
529
530 inode_lock(d_inode(parent));
531
532 req->r_inode = inode;
533 ihold(inode);
534 req->r_ino2 = ceph_vino(d_inode(parent));
535 req->r_parent = d_inode(parent);
536 set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
537 req->r_num_caps = 2;
538 err = ceph_mdsc_do_request(mdsc, NULL, req);
539
540 inode_unlock(d_inode(parent));
541
542 if (!err) {
543 struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
544 memcpy(name, rinfo->dname, rinfo->dname_len);
545 name[rinfo->dname_len] = 0;
546 dout("get_name %p ino %llx.%llx name %s\n",
547 child, ceph_vinop(inode), name);
548 } else {
549 dout("get_name %p ino %llx.%llx err %d\n",
550 child, ceph_vinop(inode), err);
551 }
552
553 ceph_mdsc_put_request(req);
554 return err;
555 }
556
557 const struct export_operations ceph_export_ops = {
558 .encode_fh = ceph_encode_fh,
559 .fh_to_dentry = ceph_fh_to_dentry,
560 .fh_to_parent = ceph_fh_to_parent,
561 .get_parent = ceph_get_parent,
562 .get_name = ceph_get_name,
563 };
564