export.c

  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 <linux/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
 36#define BYTES_PER_U32		(sizeof(u32))
 37#define CEPH_FH_BASIC_SIZE \
 38	(sizeof(struct ceph_nfs_fh) / BYTES_PER_U32)
 39#define CEPH_FH_WITH_PARENT_SIZE \
 40	(sizeof(struct ceph_nfs_confh) / BYTES_PER_U32)
 41#define CEPH_FH_SNAPPED_INODE_SIZE \
 42	(sizeof(struct ceph_nfs_snapfh) / BYTES_PER_U32)
 43
 44static int ceph_encode_snapfh(struct inode *inode, u32 *rawfh, int *max_len,
 45			      struct inode *parent_inode)
 46{
 47	struct ceph_client *cl = ceph_inode_to_client(inode);
 48	static const int snap_handle_length = CEPH_FH_SNAPPED_INODE_SIZE;
 49	struct ceph_nfs_snapfh *sfh = (void *)rawfh;
 50	u64 snapid = ceph_snap(inode);
 51	int ret;
 52	bool no_parent = true;
 53
 54	if (*max_len < snap_handle_length) {
 55		*max_len = snap_handle_length;
 56		ret = FILEID_INVALID;
 57		goto out;
 58	}
 59
 60	ret =  -EINVAL;
 61	if (snapid != CEPH_SNAPDIR) {
 62		struct inode *dir;
 63		struct dentry *dentry = d_find_alias(inode);
 64		if (!dentry)
 65			goto out;
 66
 67		rcu_read_lock();
 68		dir = d_inode_rcu(dentry->d_parent);
 69		if (ceph_snap(dir) != CEPH_SNAPDIR) {
 70			sfh->parent_ino = ceph_ino(dir);
 71			sfh->hash = ceph_dentry_hash(dir, dentry);
 72			no_parent = false;
 73		}
 74		rcu_read_unlock();
 75		dput(dentry);
 76	}
 77
 78	if (no_parent) {
 79		if (!S_ISDIR(inode->i_mode))
 80			goto out;
 81		sfh->parent_ino = sfh->ino;
 82		sfh->hash = 0;
 83	}
 84	sfh->ino = ceph_ino(inode);
 85	sfh->snapid = snapid;
 86
 87	*max_len = snap_handle_length;
 88	ret = FILEID_BTRFS_WITH_PARENT;
 89out:
 90	doutc(cl, "%p %llx.%llx ret=%d\n", inode, ceph_vinop(inode), ret);
 91	return ret;
 92}
 93
 94static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
 95			  struct inode *parent_inode)
 96{
 97	struct ceph_client *cl = ceph_inode_to_client(inode);
 98	static const int handle_length = CEPH_FH_BASIC_SIZE;
 99	static const int connected_handle_length = CEPH_FH_WITH_PARENT_SIZE;
100	int type;
101
102	if (ceph_snap(inode) != CEPH_NOSNAP)
103		return ceph_encode_snapfh(inode, rawfh, max_len, parent_inode);
104
105	if (parent_inode && (*max_len < connected_handle_length)) {
106		*max_len = connected_handle_length;
107		return FILEID_INVALID;
108	} else if (*max_len < handle_length) {
109		*max_len = handle_length;
110		return FILEID_INVALID;
111	}
112
113	if (parent_inode) {
114		struct ceph_nfs_confh *cfh = (void *)rawfh;
115		doutc(cl, "%p %llx.%llx with parent %p %llx.%llx\n", inode,
116		      ceph_vinop(inode), parent_inode, ceph_vinop(parent_inode));
117		cfh->ino = ceph_ino(inode);
118		cfh->parent_ino = ceph_ino(parent_inode);
119		*max_len = connected_handle_length;
120		type = FILEID_INO32_GEN_PARENT;
121	} else {
122		struct ceph_nfs_fh *fh = (void *)rawfh;
123		doutc(cl, "%p %llx.%llx\n", inode, ceph_vinop(inode));
124		fh->ino = ceph_ino(inode);
125		*max_len = handle_length;
126		type = FILEID_INO32_GEN;
127	}
128	return type;
129}
130
131static struct inode *__lookup_inode(struct super_block *sb, u64 ino)
132{
133	struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(sb)->mdsc;
134	struct inode *inode;
135	struct ceph_vino vino;
136	int err;
137
138	vino.ino = ino;
139	vino.snap = CEPH_NOSNAP;
140
141	if (ceph_vino_is_reserved(vino))
142		return ERR_PTR(-ESTALE);
143
144	inode = ceph_find_inode(sb, vino);
145	if (!inode) {
146		struct ceph_mds_request *req;
147		int mask;
148
149		req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
150					       USE_ANY_MDS);
151		if (IS_ERR(req))
152			return ERR_CAST(req);
153
154		mask = CEPH_STAT_CAP_INODE;
155		if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
156			mask |= CEPH_CAP_XATTR_SHARED;
157		req->r_args.lookupino.mask = cpu_to_le32(mask);
158
159		req->r_ino1 = vino;
160		req->r_num_caps = 1;
161		err = ceph_mdsc_do_request(mdsc, NULL, req);
162		inode = req->r_target_inode;
163		if (inode)
164			ihold(inode);
165		ceph_mdsc_put_request(req);
166		if (!inode)
167			return err < 0 ? ERR_PTR(err) : ERR_PTR(-ESTALE);
168	} else {
169		if (ceph_inode_is_shutdown(inode)) {
170			iput(inode);
171			return ERR_PTR(-ESTALE);
172		}
173	}
174	return inode;
175}
176
177struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino)
178{
179	struct inode *inode = __lookup_inode(sb, ino);
180	if (IS_ERR(inode))
181		return inode;
182	if (inode->i_nlink == 0) {
183		iput(inode);
184		return ERR_PTR(-ESTALE);
185	}
186	return inode;
187}
188
189static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
190{
191	struct inode *inode = __lookup_inode(sb, ino);
192	struct ceph_inode_info *ci = ceph_inode(inode);
193	int err;
194
195	if (IS_ERR(inode))
196		return ERR_CAST(inode);
197	/* We need LINK caps to reliably check i_nlink */
198	err = ceph_do_getattr(inode, CEPH_CAP_LINK_SHARED, false);
199	if (err) {
200		iput(inode);
201		return ERR_PTR(err);
202	}
203	/* -ESTALE if inode as been unlinked and no file is open */
204	if ((inode->i_nlink == 0) && !__ceph_is_file_opened(ci)) {
205		iput(inode);
206		return ERR_PTR(-ESTALE);
207	}
208	return d_obtain_alias(inode);
209}
210
211static struct dentry *__snapfh_to_dentry(struct super_block *sb,
212					  struct ceph_nfs_snapfh *sfh,
213					  bool want_parent)
214{
215	struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(sb)->mdsc;
216	struct ceph_client *cl = mdsc->fsc->client;
217	struct ceph_mds_request *req;
218	struct inode *inode;
219	struct ceph_vino vino;
220	int mask;
221	int err;
222	bool unlinked = false;
223
224	if (want_parent) {
225		vino.ino = sfh->parent_ino;
226		if (sfh->snapid == CEPH_SNAPDIR)
227			vino.snap = CEPH_NOSNAP;
228		else if (sfh->ino == sfh->parent_ino)
229			vino.snap = CEPH_SNAPDIR;
230		else
231			vino.snap = sfh->snapid;
232	} else {
233		vino.ino = sfh->ino;
234		vino.snap = sfh->snapid;
235	}
236
237	if (ceph_vino_is_reserved(vino))
238		return ERR_PTR(-ESTALE);
239
240	inode = ceph_find_inode(sb, vino);
241	if (inode) {
242		if (ceph_inode_is_shutdown(inode)) {
243			iput(inode);
244			return ERR_PTR(-ESTALE);
245		}
246		return d_obtain_alias(inode);
247	}
248
249	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
250				       USE_ANY_MDS);
251	if (IS_ERR(req))
252		return ERR_CAST(req);
253
254	mask = CEPH_STAT_CAP_INODE;
255	if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
256		mask |= CEPH_CAP_XATTR_SHARED;
257	req->r_args.lookupino.mask = cpu_to_le32(mask);
258	if (vino.snap < CEPH_NOSNAP) {
259		req->r_args.lookupino.snapid = cpu_to_le64(vino.snap);
260		if (!want_parent && sfh->ino != sfh->parent_ino) {
261			req->r_args.lookupino.parent =
262					cpu_to_le64(sfh->parent_ino);
263			req->r_args.lookupino.hash =
264					cpu_to_le32(sfh->hash);
265		}
266	}
267
268	req->r_ino1 = vino;
269	req->r_num_caps = 1;
270	err = ceph_mdsc_do_request(mdsc, NULL, req);
271	inode = req->r_target_inode;
272	if (inode) {
273		if (vino.snap == CEPH_SNAPDIR) {
274			if (inode->i_nlink == 0)
275				unlinked = true;
276			inode = ceph_get_snapdir(inode);
277		} else if (ceph_snap(inode) == vino.snap) {
278			ihold(inode);
279		} else {
280			/* mds does not support lookup snapped inode */
281			inode = ERR_PTR(-EOPNOTSUPP);
282		}
283	} else {
284		inode = ERR_PTR(-ESTALE);
285	}
286	ceph_mdsc_put_request(req);
287
288	if (want_parent) {
289		doutc(cl, "%llx.%llx\n err=%d\n", vino.ino, vino.snap, err);
290	} else {
291		doutc(cl, "%llx.%llx parent %llx hash %x err=%d", vino.ino,
292		      vino.snap, sfh->parent_ino, sfh->hash, err);
293	}
294	/* see comments in ceph_get_parent() */
295	return unlinked ? d_obtain_root(inode) : d_obtain_alias(inode);
296}
297
298/*
299 * convert regular fh to dentry
300 */
301static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
302					struct fid *fid,
303					int fh_len, int fh_type)
304{
305	struct ceph_fs_client *fsc = ceph_sb_to_fs_client(sb);
306	struct ceph_nfs_fh *fh = (void *)fid->raw;
307
308	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
309		struct ceph_nfs_snapfh *sfh = (void *)fid->raw;
310		return __snapfh_to_dentry(sb, sfh, false);
311	}
312
313	if (fh_type != FILEID_INO32_GEN  &&
314	    fh_type != FILEID_INO32_GEN_PARENT)
315		return NULL;
316	if (fh_len < sizeof(*fh) / BYTES_PER_U32)
317		return NULL;
318
319	doutc(fsc->client, "%llx\n", fh->ino);
320	return __fh_to_dentry(sb, fh->ino);
321}
322
323static struct dentry *__get_parent(struct super_block *sb,
324				   struct dentry *child, u64 ino)
325{
326	struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(sb)->mdsc;
327	struct ceph_mds_request *req;
328	struct inode *inode;
329	int mask;
330	int err;
331
332	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
333				       USE_ANY_MDS);
334	if (IS_ERR(req))
335		return ERR_CAST(req);
336
337	if (child) {
338		req->r_inode = d_inode(child);
339		ihold(d_inode(child));
340	} else {
341		req->r_ino1 = (struct ceph_vino) {
342			.ino = ino,
343			.snap = CEPH_NOSNAP,
344		};
345	}
346
347	mask = CEPH_STAT_CAP_INODE;
348	if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
349		mask |= CEPH_CAP_XATTR_SHARED;
350	req->r_args.getattr.mask = cpu_to_le32(mask);
351
352	req->r_num_caps = 1;
353	err = ceph_mdsc_do_request(mdsc, NULL, req);
354	if (err) {
355		ceph_mdsc_put_request(req);
356		return ERR_PTR(err);
357	}
358
359	inode = req->r_target_inode;
360	if (inode)
361		ihold(inode);
362	ceph_mdsc_put_request(req);
363	if (!inode)
364		return ERR_PTR(-ENOENT);
365
366	return d_obtain_alias(inode);
367}
368
369static struct dentry *ceph_get_parent(struct dentry *child)
370{
371	struct inode *inode = d_inode(child);
372	struct ceph_client *cl = ceph_inode_to_client(inode);
373	struct dentry *dn;
374
375	if (ceph_snap(inode) != CEPH_NOSNAP) {
376		struct inode* dir;
377		bool unlinked = false;
378		/* do not support non-directory */
379		if (!d_is_dir(child)) {
380			dn = ERR_PTR(-EINVAL);
381			goto out;
382		}
383		dir = __lookup_inode(inode->i_sb, ceph_ino(inode));
384		if (IS_ERR(dir)) {
385			dn = ERR_CAST(dir);
386			goto out;
387		}
388		/* There can be multiple paths to access snapped inode.
389		 * For simplicity, treat snapdir of head inode as parent */
390		if (ceph_snap(inode) != CEPH_SNAPDIR) {
391			struct inode *snapdir = ceph_get_snapdir(dir);
392			if (dir->i_nlink == 0)
393				unlinked = true;
394			iput(dir);
395			if (IS_ERR(snapdir)) {
396				dn = ERR_CAST(snapdir);
397				goto out;
398			}
399			dir = snapdir;
400		}
401		/* If directory has already been deleted, further get_parent
402		 * will fail. Do not mark snapdir dentry as disconnected,
403		 * this prevents exportfs from doing further get_parent. */
404		if (unlinked)
405			dn = d_obtain_root(dir);
406		else
407			dn = d_obtain_alias(dir);
408	} else {
409		dn = __get_parent(child->d_sb, child, 0);
410	}
411out:
412	doutc(cl, "child %p %p %llx.%llx err=%ld\n", child, inode,
413	      ceph_vinop(inode), (long)PTR_ERR_OR_ZERO(dn));
414	return dn;
415}
416
417/*
418 * convert regular fh to parent
419 */
420static struct dentry *ceph_fh_to_parent(struct super_block *sb,
421					struct fid *fid,
422					int fh_len, int fh_type)
423{
424	struct ceph_fs_client *fsc = ceph_sb_to_fs_client(sb);
425	struct ceph_nfs_confh *cfh = (void *)fid->raw;
426	struct dentry *dentry;
427
428	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
429		struct ceph_nfs_snapfh *sfh = (void *)fid->raw;
430		return __snapfh_to_dentry(sb, sfh, true);
431	}
432
433	if (fh_type != FILEID_INO32_GEN_PARENT)
434		return NULL;
435	if (fh_len < sizeof(*cfh) / BYTES_PER_U32)
436		return NULL;
437
438	doutc(fsc->client, "%llx\n", cfh->parent_ino);
439	dentry = __get_parent(sb, NULL, cfh->ino);
440	if (unlikely(dentry == ERR_PTR(-ENOENT)))
441		dentry = __fh_to_dentry(sb, cfh->parent_ino);
442	return dentry;
443}
444
445static int __get_snap_name(struct dentry *parent, char *name,
446			   struct dentry *child)
447{
448	struct inode *inode = d_inode(child);
449	struct inode *dir = d_inode(parent);
450	struct ceph_fs_client *fsc = ceph_inode_to_fs_client(inode);
451	struct ceph_mds_request *req = NULL;
452	char *last_name = NULL;
453	unsigned next_offset = 2;
454	int err = -EINVAL;
455
456	if (ceph_ino(inode) != ceph_ino(dir))
457		goto out;
458	if (ceph_snap(inode) == CEPH_SNAPDIR) {
459		if (ceph_snap(dir) == CEPH_NOSNAP) {
460			/*
461			 * .get_name() from struct export_operations
462			 * assumes that its 'name' parameter is pointing
463			 * to a NAME_MAX+1 sized buffer
464			 */
465			strscpy(name, fsc->mount_options->snapdir_name,
466				NAME_MAX + 1);
467			err = 0;
468		}
469		goto out;
470	}
471	if (ceph_snap(dir) != CEPH_SNAPDIR)
472		goto out;
473
474	while (1) {
475		struct ceph_mds_reply_info_parsed *rinfo;
476		struct ceph_mds_reply_dir_entry *rde;
477		int i;
478
479		req = ceph_mdsc_create_request(fsc->mdsc, CEPH_MDS_OP_LSSNAP,
480					       USE_AUTH_MDS);
481		if (IS_ERR(req)) {
482			err = PTR_ERR(req);
483			req = NULL;
484			goto out;
485		}
486		err = ceph_alloc_readdir_reply_buffer(req, inode);
487		if (err)
488			goto out;
489
490		req->r_direct_mode = USE_AUTH_MDS;
491		req->r_readdir_offset = next_offset;
492		req->r_args.readdir.flags =
493				cpu_to_le16(CEPH_READDIR_REPLY_BITFLAGS);
494		if (last_name) {
495			req->r_path2 = last_name;
496			last_name = NULL;
497		}
498
499		req->r_inode = dir;
500		ihold(dir);
501		req->r_dentry = dget(parent);
502
503		inode_lock(dir);
504		err = ceph_mdsc_do_request(fsc->mdsc, NULL, req);
505		inode_unlock(dir);
506
507		if (err < 0)
508			goto out;
509
510		rinfo = &req->r_reply_info;
511		for (i = 0; i < rinfo->dir_nr; i++) {
512			rde = rinfo->dir_entries + i;
513			BUG_ON(!rde->inode.in);
514			if (ceph_snap(inode) ==
515			    le64_to_cpu(rde->inode.in->snapid)) {
516				memcpy(name, rde->name, rde->name_len);
517				name[rde->name_len] = '\0';
518				err = 0;
519				goto out;
520			}
521		}
522
523		if (rinfo->dir_end)
524			break;
525
526		BUG_ON(rinfo->dir_nr <= 0);
527		rde = rinfo->dir_entries + (rinfo->dir_nr - 1);
528		next_offset += rinfo->dir_nr;
529		last_name = kstrndup(rde->name, rde->name_len, GFP_KERNEL);
530		if (!last_name) {
531			err = -ENOMEM;
532			goto out;
533		}
534
535		ceph_mdsc_put_request(req);
536		req = NULL;
537	}
538	err = -ENOENT;
539out:
540	if (req)
541		ceph_mdsc_put_request(req);
542	kfree(last_name);
543	doutc(fsc->client, "child dentry %p %p %llx.%llx err=%d\n", child,
544	      inode, ceph_vinop(inode), err);
545	return err;
546}
547
548static int ceph_get_name(struct dentry *parent, char *name,
549			 struct dentry *child)
550{
551	struct ceph_mds_client *mdsc;
552	struct ceph_mds_request *req;
553	struct inode *dir = d_inode(parent);
554	struct inode *inode = d_inode(child);
555	struct ceph_mds_reply_info_parsed *rinfo;
556	int err;
557
558	if (ceph_snap(inode) != CEPH_NOSNAP)
559		return __get_snap_name(parent, name, child);
560
561	mdsc = ceph_inode_to_fs_client(inode)->mdsc;
562	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
563				       USE_ANY_MDS);
564	if (IS_ERR(req))
565		return PTR_ERR(req);
566
567	inode_lock(dir);
568	req->r_inode = inode;
569	ihold(inode);
570	req->r_ino2 = ceph_vino(d_inode(parent));
571	req->r_parent = dir;
572	ihold(dir);
573	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
574	req->r_num_caps = 2;
575	err = ceph_mdsc_do_request(mdsc, NULL, req);
576	inode_unlock(dir);
577
578	if (err)
579		goto out;
580
581	rinfo = &req->r_reply_info;
582	if (!IS_ENCRYPTED(dir)) {
583		memcpy(name, rinfo->dname, rinfo->dname_len);
584		name[rinfo->dname_len] = 0;
585	} else {
586		struct fscrypt_str oname = FSTR_INIT(NULL, 0);
587		struct ceph_fname fname = { .dir	= dir,
588					    .name	= rinfo->dname,
589					    .ctext	= rinfo->altname,
590					    .name_len	= rinfo->dname_len,
591					    .ctext_len	= rinfo->altname_len };
592
593		err = ceph_fname_alloc_buffer(dir, &oname);
594		if (err < 0)
595			goto out;
596
597		err = ceph_fname_to_usr(&fname, NULL, &oname, NULL);
598		if (!err) {
599			memcpy(name, oname.name, oname.len);
600			name[oname.len] = 0;
601		}
602		ceph_fname_free_buffer(dir, &oname);
603	}
604out:
605	doutc(mdsc->fsc->client, "child dentry %p %p %llx.%llx err %d %s%s\n",
606	      child, inode, ceph_vinop(inode), err, err ? "" : "name ",
607	      err ? "" : name);
608	ceph_mdsc_put_request(req);
609	return err;
610}
611
612const struct export_operations ceph_export_ops = {
613	.encode_fh = ceph_encode_fh,
614	.fh_to_dentry = ceph_fh_to_dentry,
615	.fh_to_parent = ceph_fh_to_parent,
616	.get_parent = ceph_get_parent,
617	.get_name = ceph_get_name,
618};