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#include "crypto.h"
11
12/*
13 * Basic fh
14 */
15struct ceph_nfs_fh {
16 u64 ino;
17} __attribute__ ((packed));
18
19/*
20 * Larger fh that includes parent ino.
21 */
22struct ceph_nfs_confh {
23 u64 ino, parent_ino;
24} __attribute__ ((packed));
25
26/*
27 * fh for snapped inode
28 */
29struct ceph_nfs_snapfh {
30 u64 ino;
31 u64 snapid;
32 u64 parent_ino;
33 u32 hash;
34} __attribute__ ((packed));
35
36static int ceph_encode_snapfh(struct inode *inode, u32 *rawfh, int *max_len,
37 struct inode *parent_inode)
38{
39 static const int snap_handle_length =
40 sizeof(struct ceph_nfs_snapfh) >> 2;
41 struct ceph_nfs_snapfh *sfh = (void *)rawfh;
42 u64 snapid = ceph_snap(inode);
43 int ret;
44 bool no_parent = true;
45
46 if (*max_len < snap_handle_length) {
47 *max_len = snap_handle_length;
48 ret = FILEID_INVALID;
49 goto out;
50 }
51
52 ret = -EINVAL;
53 if (snapid != CEPH_SNAPDIR) {
54 struct inode *dir;
55 struct dentry *dentry = d_find_alias(inode);
56 if (!dentry)
57 goto out;
58
59 rcu_read_lock();
60 dir = d_inode_rcu(dentry: dentry->d_parent);
61 if (ceph_snap(inode: dir) != CEPH_SNAPDIR) {
62 sfh->parent_ino = ceph_ino(inode: dir);
63 sfh->hash = ceph_dentry_hash(dir, dn: dentry);
64 no_parent = false;
65 }
66 rcu_read_unlock();
67 dput(dentry);
68 }
69
70 if (no_parent) {
71 if (!S_ISDIR(inode->i_mode))
72 goto out;
73 sfh->parent_ino = sfh->ino;
74 sfh->hash = 0;
75 }
76 sfh->ino = ceph_ino(inode);
77 sfh->snapid = snapid;
78
79 *max_len = snap_handle_length;
80 ret = FILEID_BTRFS_WITH_PARENT;
81out:
82 dout("encode_snapfh %llx.%llx ret=%d\n", ceph_vinop(inode), ret);
83 return ret;
84}
85
86static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
87 struct inode *parent_inode)
88{
89 static const int handle_length =
90 sizeof(struct ceph_nfs_fh) >> 2;
91 static const int connected_handle_length =
92 sizeof(struct ceph_nfs_confh) >> 2;
93 int type;
94
95 if (ceph_snap(inode) != CEPH_NOSNAP)
96 return ceph_encode_snapfh(inode, rawfh, max_len, parent_inode);
97
98 if (parent_inode && (*max_len < connected_handle_length)) {
99 *max_len = connected_handle_length;
100 return FILEID_INVALID;
101 } else if (*max_len < handle_length) {
102 *max_len = handle_length;
103 return FILEID_INVALID;
104 }
105
106 if (parent_inode) {
107 struct ceph_nfs_confh *cfh = (void *)rawfh;
108 dout("encode_fh %llx with parent %llx\n",
109 ceph_ino(inode), ceph_ino(parent_inode));
110 cfh->ino = ceph_ino(inode);
111 cfh->parent_ino = ceph_ino(inode: parent_inode);
112 *max_len = connected_handle_length;
113 type = FILEID_INO32_GEN_PARENT;
114 } else {
115 struct ceph_nfs_fh *fh = (void *)rawfh;
116 dout("encode_fh %llx\n", ceph_ino(inode));
117 fh->ino = ceph_ino(inode);
118 *max_len = handle_length;
119 type = FILEID_INO32_GEN;
120 }
121 return type;
122}
123
124static struct inode *__lookup_inode(struct super_block *sb, u64 ino)
125{
126 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
127 struct inode *inode;
128 struct ceph_vino vino;
129 int err;
130
131 vino.ino = ino;
132 vino.snap = CEPH_NOSNAP;
133
134 if (ceph_vino_is_reserved(vino))
135 return ERR_PTR(error: -ESTALE);
136
137 inode = ceph_find_inode(sb, vino);
138 if (!inode) {
139 struct ceph_mds_request *req;
140 int mask;
141
142 req = ceph_mdsc_create_request(mdsc, op: CEPH_MDS_OP_LOOKUPINO,
143 mode: USE_ANY_MDS);
144 if (IS_ERR(ptr: req))
145 return ERR_CAST(ptr: req);
146
147 mask = CEPH_STAT_CAP_INODE;
148 if (ceph_security_xattr_wanted(in: d_inode(dentry: sb->s_root)))
149 mask |= CEPH_CAP_XATTR_SHARED;
150 req->r_args.lookupino.mask = cpu_to_le32(mask);
151
152 req->r_ino1 = vino;
153 req->r_num_caps = 1;
154 err = ceph_mdsc_do_request(mdsc, NULL, req);
155 inode = req->r_target_inode;
156 if (inode)
157 ihold(inode);
158 ceph_mdsc_put_request(req);
159 if (!inode)
160 return err < 0 ? ERR_PTR(error: err) : ERR_PTR(error: -ESTALE);
161 } else {
162 if (ceph_inode_is_shutdown(inode)) {
163 iput(inode);
164 return ERR_PTR(error: -ESTALE);
165 }
166 }
167 return inode;
168}
169
170struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino)
171{
172 struct inode *inode = __lookup_inode(sb, ino);
173 if (IS_ERR(ptr: inode))
174 return inode;
175 if (inode->i_nlink == 0) {
176 iput(inode);
177 return ERR_PTR(error: -ESTALE);
178 }
179 return inode;
180}
181
182static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
183{
184 struct inode *inode = __lookup_inode(sb, ino);
185 struct ceph_inode_info *ci = ceph_inode(inode);
186 int err;
187
188 if (IS_ERR(ptr: inode))
189 return ERR_CAST(ptr: inode);
190 /* We need LINK caps to reliably check i_nlink */
191 err = ceph_do_getattr(inode, CEPH_CAP_LINK_SHARED, force: false);
192 if (err) {
193 iput(inode);
194 return ERR_PTR(error: err);
195 }
196 /* -ESTALE if inode as been unlinked and no file is open */
197 if ((inode->i_nlink == 0) && !__ceph_is_file_opened(ci)) {
198 iput(inode);
199 return ERR_PTR(error: -ESTALE);
200 }
201 return d_obtain_alias(inode);
202}
203
204static struct dentry *__snapfh_to_dentry(struct super_block *sb,
205 struct ceph_nfs_snapfh *sfh,
206 bool want_parent)
207{
208 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
209 struct ceph_mds_request *req;
210 struct inode *inode;
211 struct ceph_vino vino;
212 int mask;
213 int err;
214 bool unlinked = false;
215
216 if (want_parent) {
217 vino.ino = sfh->parent_ino;
218 if (sfh->snapid == CEPH_SNAPDIR)
219 vino.snap = CEPH_NOSNAP;
220 else if (sfh->ino == sfh->parent_ino)
221 vino.snap = CEPH_SNAPDIR;
222 else
223 vino.snap = sfh->snapid;
224 } else {
225 vino.ino = sfh->ino;
226 vino.snap = sfh->snapid;
227 }
228
229 if (ceph_vino_is_reserved(vino))
230 return ERR_PTR(error: -ESTALE);
231
232 inode = ceph_find_inode(sb, vino);
233 if (inode) {
234 if (ceph_inode_is_shutdown(inode)) {
235 iput(inode);
236 return ERR_PTR(error: -ESTALE);
237 }
238 return d_obtain_alias(inode);
239 }
240
241 req = ceph_mdsc_create_request(mdsc, op: CEPH_MDS_OP_LOOKUPINO,
242 mode: USE_ANY_MDS);
243 if (IS_ERR(ptr: req))
244 return ERR_CAST(ptr: req);
245
246 mask = CEPH_STAT_CAP_INODE;
247 if (ceph_security_xattr_wanted(in: d_inode(dentry: sb->s_root)))
248 mask |= CEPH_CAP_XATTR_SHARED;
249 req->r_args.lookupino.mask = cpu_to_le32(mask);
250 if (vino.snap < CEPH_NOSNAP) {
251 req->r_args.lookupino.snapid = cpu_to_le64(vino.snap);
252 if (!want_parent && sfh->ino != sfh->parent_ino) {
253 req->r_args.lookupino.parent =
254 cpu_to_le64(sfh->parent_ino);
255 req->r_args.lookupino.hash =
256 cpu_to_le32(sfh->hash);
257 }
258 }
259
260 req->r_ino1 = vino;
261 req->r_num_caps = 1;
262 err = ceph_mdsc_do_request(mdsc, NULL, req);
263 inode = req->r_target_inode;
264 if (inode) {
265 if (vino.snap == CEPH_SNAPDIR) {
266 if (inode->i_nlink == 0)
267 unlinked = true;
268 inode = ceph_get_snapdir(parent: inode);
269 } else if (ceph_snap(inode) == vino.snap) {
270 ihold(inode);
271 } else {
272 /* mds does not support lookup snapped inode */
273 inode = ERR_PTR(error: -EOPNOTSUPP);
274 }
275 } else {
276 inode = ERR_PTR(error: -ESTALE);
277 }
278 ceph_mdsc_put_request(req);
279
280 if (want_parent) {
281 dout("snapfh_to_parent %llx.%llx\n err=%d\n",
282 vino.ino, vino.snap, err);
283 } else {
284 dout("snapfh_to_dentry %llx.%llx parent %llx hash %x err=%d",
285 vino.ino, vino.snap, sfh->parent_ino, sfh->hash, err);
286 }
287 if (IS_ERR(ptr: inode))
288 return ERR_CAST(ptr: inode);
289 /* see comments in ceph_get_parent() */
290 return unlinked ? d_obtain_root(inode) : d_obtain_alias(inode);
291}
292
293/*
294 * convert regular fh to dentry
295 */
296static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
297 struct fid *fid,
298 int fh_len, int fh_type)
299{
300 struct ceph_nfs_fh *fh = (void *)fid->raw;
301
302 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
303 struct ceph_nfs_snapfh *sfh = (void *)fid->raw;
304 return __snapfh_to_dentry(sb, sfh, want_parent: false);
305 }
306
307 if (fh_type != FILEID_INO32_GEN &&
308 fh_type != FILEID_INO32_GEN_PARENT)
309 return NULL;
310 if (fh_len < sizeof(*fh) / 4)
311 return NULL;
312
313 dout("fh_to_dentry %llx\n", fh->ino);
314 return __fh_to_dentry(sb, ino: fh->ino);
315}
316
317static struct dentry *__get_parent(struct super_block *sb,
318 struct dentry *child, u64 ino)
319{
320 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
321 struct ceph_mds_request *req;
322 struct inode *inode;
323 int mask;
324 int err;
325
326 req = ceph_mdsc_create_request(mdsc, op: CEPH_MDS_OP_LOOKUPPARENT,
327 mode: USE_ANY_MDS);
328 if (IS_ERR(ptr: req))
329 return ERR_CAST(ptr: req);
330
331 if (child) {
332 req->r_inode = d_inode(dentry: child);
333 ihold(inode: d_inode(dentry: child));
334 } else {
335 req->r_ino1 = (struct ceph_vino) {
336 .ino = ino,
337 .snap = CEPH_NOSNAP,
338 };
339 }
340
341 mask = CEPH_STAT_CAP_INODE;
342 if (ceph_security_xattr_wanted(in: d_inode(dentry: sb->s_root)))
343 mask |= CEPH_CAP_XATTR_SHARED;
344 req->r_args.getattr.mask = cpu_to_le32(mask);
345
346 req->r_num_caps = 1;
347 err = ceph_mdsc_do_request(mdsc, NULL, req);
348 if (err) {
349 ceph_mdsc_put_request(req);
350 return ERR_PTR(error: err);
351 }
352
353 inode = req->r_target_inode;
354 if (inode)
355 ihold(inode);
356 ceph_mdsc_put_request(req);
357 if (!inode)
358 return ERR_PTR(error: -ENOENT);
359
360 return d_obtain_alias(inode);
361}
362
363static struct dentry *ceph_get_parent(struct dentry *child)
364{
365 struct inode *inode = d_inode(dentry: child);
366 struct dentry *dn;
367
368 if (ceph_snap(inode) != CEPH_NOSNAP) {
369 struct inode* dir;
370 bool unlinked = false;
371 /* do not support non-directory */
372 if (!d_is_dir(dentry: child)) {
373 dn = ERR_PTR(error: -EINVAL);
374 goto out;
375 }
376 dir = __lookup_inode(sb: inode->i_sb, ino: ceph_ino(inode));
377 if (IS_ERR(ptr: dir)) {
378 dn = ERR_CAST(ptr: dir);
379 goto out;
380 }
381 /* There can be multiple paths to access snapped inode.
382 * For simplicity, treat snapdir of head inode as parent */
383 if (ceph_snap(inode) != CEPH_SNAPDIR) {
384 struct inode *snapdir = ceph_get_snapdir(parent: dir);
385 if (dir->i_nlink == 0)
386 unlinked = true;
387 iput(dir);
388 if (IS_ERR(ptr: snapdir)) {
389 dn = ERR_CAST(ptr: snapdir);
390 goto out;
391 }
392 dir = snapdir;
393 }
394 /* If directory has already been deleted, futher get_parent
395 * will fail. Do not mark snapdir dentry as disconnected,
396 * this prevent exportfs from doing futher get_parent. */
397 if (unlinked)
398 dn = d_obtain_root(dir);
399 else
400 dn = d_obtain_alias(dir);
401 } else {
402 dn = __get_parent(sb: child->d_sb, child, ino: 0);
403 }
404out:
405 dout("get_parent %p ino %llx.%llx err=%ld\n",
406 child, ceph_vinop(inode), (long)PTR_ERR_OR_ZERO(dn));
407 return dn;
408}
409
410/*
411 * convert regular fh to parent
412 */
413static struct dentry *ceph_fh_to_parent(struct super_block *sb,
414 struct fid *fid,
415 int fh_len, int fh_type)
416{
417 struct ceph_nfs_confh *cfh = (void *)fid->raw;
418 struct dentry *dentry;
419
420 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
421 struct ceph_nfs_snapfh *sfh = (void *)fid->raw;
422 return __snapfh_to_dentry(sb, sfh, want_parent: true);
423 }
424
425 if (fh_type != FILEID_INO32_GEN_PARENT)
426 return NULL;
427 if (fh_len < sizeof(*cfh) / 4)
428 return NULL;
429
430 dout("fh_to_parent %llx\n", cfh->parent_ino);
431 dentry = __get_parent(sb, NULL, ino: cfh->ino);
432 if (unlikely(dentry == ERR_PTR(-ENOENT)))
433 dentry = __fh_to_dentry(sb, ino: cfh->parent_ino);
434 return dentry;
435}
436
437static int __get_snap_name(struct dentry *parent, char *name,
438 struct dentry *child)
439{
440 struct inode *inode = d_inode(dentry: child);
441 struct inode *dir = d_inode(dentry: parent);
442 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
443 struct ceph_mds_request *req = NULL;
444 char *last_name = NULL;
445 unsigned next_offset = 2;
446 int err = -EINVAL;
447
448 if (ceph_ino(inode) != ceph_ino(inode: dir))
449 goto out;
450 if (ceph_snap(inode) == CEPH_SNAPDIR) {
451 if (ceph_snap(inode: dir) == CEPH_NOSNAP) {
452 strcpy(p: name, q: fsc->mount_options->snapdir_name);
453 err = 0;
454 }
455 goto out;
456 }
457 if (ceph_snap(inode: dir) != CEPH_SNAPDIR)
458 goto out;
459
460 while (1) {
461 struct ceph_mds_reply_info_parsed *rinfo;
462 struct ceph_mds_reply_dir_entry *rde;
463 int i;
464
465 req = ceph_mdsc_create_request(mdsc: fsc->mdsc, op: CEPH_MDS_OP_LSSNAP,
466 mode: USE_AUTH_MDS);
467 if (IS_ERR(ptr: req)) {
468 err = PTR_ERR(ptr: req);
469 req = NULL;
470 goto out;
471 }
472 err = ceph_alloc_readdir_reply_buffer(req, dir: inode);
473 if (err)
474 goto out;
475
476 req->r_direct_mode = USE_AUTH_MDS;
477 req->r_readdir_offset = next_offset;
478 req->r_args.readdir.flags =
479 cpu_to_le16(CEPH_READDIR_REPLY_BITFLAGS);
480 if (last_name) {
481 req->r_path2 = last_name;
482 last_name = NULL;
483 }
484
485 req->r_inode = dir;
486 ihold(inode: dir);
487 req->r_dentry = dget(dentry: parent);
488
489 inode_lock(inode: dir);
490 err = ceph_mdsc_do_request(mdsc: fsc->mdsc, NULL, req);
491 inode_unlock(inode: dir);
492
493 if (err < 0)
494 goto out;
495
496 rinfo = &req->r_reply_info;
497 for (i = 0; i < rinfo->dir_nr; i++) {
498 rde = rinfo->dir_entries + i;
499 BUG_ON(!rde->inode.in);
500 if (ceph_snap(inode) ==
501 le64_to_cpu(rde->inode.in->snapid)) {
502 memcpy(name, rde->name, rde->name_len);
503 name[rde->name_len] = '\0';
504 err = 0;
505 goto out;
506 }
507 }
508
509 if (rinfo->dir_end)
510 break;
511
512 BUG_ON(rinfo->dir_nr <= 0);
513 rde = rinfo->dir_entries + (rinfo->dir_nr - 1);
514 next_offset += rinfo->dir_nr;
515 last_name = kstrndup(s: rde->name, len: rde->name_len, GFP_KERNEL);
516 if (!last_name) {
517 err = -ENOMEM;
518 goto out;
519 }
520
521 ceph_mdsc_put_request(req);
522 req = NULL;
523 }
524 err = -ENOENT;
525out:
526 if (req)
527 ceph_mdsc_put_request(req);
528 kfree(objp: last_name);
529 dout("get_snap_name %p ino %llx.%llx err=%d\n",
530 child, ceph_vinop(inode), err);
531 return err;
532}
533
534static int ceph_get_name(struct dentry *parent, char *name,
535 struct dentry *child)
536{
537 struct ceph_mds_client *mdsc;
538 struct ceph_mds_request *req;
539 struct inode *dir = d_inode(dentry: parent);
540 struct inode *inode = d_inode(dentry: child);
541 struct ceph_mds_reply_info_parsed *rinfo;
542 int err;
543
544 if (ceph_snap(inode) != CEPH_NOSNAP)
545 return __get_snap_name(parent, name, child);
546
547 mdsc = ceph_inode_to_client(inode)->mdsc;
548 req = ceph_mdsc_create_request(mdsc, op: CEPH_MDS_OP_LOOKUPNAME,
549 mode: USE_ANY_MDS);
550 if (IS_ERR(ptr: req))
551 return PTR_ERR(ptr: req);
552
553 inode_lock(inode: dir);
554 req->r_inode = inode;
555 ihold(inode);
556 req->r_ino2 = ceph_vino(inode: d_inode(dentry: parent));
557 req->r_parent = dir;
558 ihold(inode: dir);
559 set_bit(CEPH_MDS_R_PARENT_LOCKED, addr: &req->r_req_flags);
560 req->r_num_caps = 2;
561 err = ceph_mdsc_do_request(mdsc, NULL, req);
562 inode_unlock(inode: dir);
563
564 if (err)
565 goto out;
566
567 rinfo = &req->r_reply_info;
568 if (!IS_ENCRYPTED(dir)) {
569 memcpy(name, rinfo->dname, rinfo->dname_len);
570 name[rinfo->dname_len] = 0;
571 } else {
572 struct fscrypt_str oname = FSTR_INIT(NULL, 0);
573 struct ceph_fname fname = { .dir = dir,
574 .name = rinfo->dname,
575 .ctext = rinfo->altname,
576 .name_len = rinfo->dname_len,
577 .ctext_len = rinfo->altname_len };
578
579 err = ceph_fname_alloc_buffer(parent: dir, fname: &oname);
580 if (err < 0)
581 goto out;
582
583 err = ceph_fname_to_usr(fname: &fname, NULL, oname: &oname, NULL);
584 if (!err) {
585 memcpy(name, oname.name, oname.len);
586 name[oname.len] = 0;
587 }
588 ceph_fname_free_buffer(parent: dir, fname: &oname);
589 }
590out:
591 dout("get_name %p ino %llx.%llx err %d %s%s\n",
592 child, ceph_vinop(inode), err,
593 err ? "" : "name ", err ? "" : name);
594 ceph_mdsc_put_request(req);
595 return err;
596}
597
598const struct export_operations ceph_export_ops = {
599 .encode_fh = ceph_encode_fh,
600 .fh_to_dentry = ceph_fh_to_dentry,
601 .fh_to_parent = ceph_fh_to_parent,
602 .get_parent = ceph_get_parent,
603 .get_name = ceph_get_name,
604};
605

source code of linux/fs/ceph/export.c