nfsfh.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
  4 *
  5 * This file describes the layout of the file handles as passed
  6 * over the wire.
  7 */
  8#ifndef _LINUX_NFSD_NFSFH_H
  9#define _LINUX_NFSD_NFSFH_H
 10
 11#include <linux/crc32.h>
 12#include <linux/sunrpc/svc.h>
 13#include <linux/iversion.h>
 14#include <linux/exportfs.h>
 15#include <linux/nfs4.h>
 16
 17#include "export.h"
 18
 19/*
 20 * The file handle starts with a sequence of four-byte words.
 21 * The first word contains a version number (1) and three descriptor bytes
 22 * that tell how the remaining 3 variable length fields should be handled.
 23 * These three bytes are auth_type, fsid_type and fileid_type.
 24 *
 25 * All four-byte values are in host-byte-order.
 26 *
 27 * The auth_type field is deprecated and must be set to 0.
 28 *
 29 * The fsid_type identifies how the filesystem (or export point) is
 30 *    encoded.
 31 *  Current values:
 32 *     0  - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
 33 *        NOTE: we cannot use the kdev_t device id value, because kdev_t.h
 34 *              says we mustn't.  We must break it up and reassemble.
 35 *     1  - 4 byte user specified identifier
 36 *     2  - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
 37 *     3  - 4 byte device id, encoded for user-space, 4 byte inode number
 38 *     4  - 4 byte inode number and 4 byte uuid
 39 *     5  - 8 byte uuid
 40 *     6  - 16 byte uuid
 41 *     7  - 8 byte inode number and 16 byte uuid
 42 *
 43 * The fileid_type identifies how the file within the filesystem is encoded.
 44 *   The values for this field are filesystem specific, exccept that
 45 *   filesystems must not use the values '0' or '0xff'. 'See enum fid_type'
 46 *   in include/linux/exportfs.h for currently registered values.
 47 */
 48
 49struct knfsd_fh {
 50	unsigned int	fh_size;	/*
 51					 * Points to the current size while
 52					 * building a new file handle.
 53					 */
 54	u8		fh_raw[NFS4_FHSIZE];
 55};
 56
 57#define fh_version		fh_raw[0]
 58#define fh_auth_type		fh_raw[1]
 59#define fh_fsid_type		fh_raw[2]
 60#define fh_fileid_type		fh_raw[3]
 61
 62static inline u32 *fh_fsid(const struct knfsd_fh *fh)
 63{
 64	return (u32 *)&fh->fh_raw[4];
 65}
 66
 67static inline __u32 ino_t_to_u32(ino_t ino)
 68{
 69	return (__u32) ino;
 70}
 71
 72static inline ino_t u32_to_ino_t(__u32 uino)
 73{
 74	return (ino_t) uino;
 75}
 76
 77/*
 78 * This is the internal representation of an NFS handle used in knfsd.
 79 * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
 80 */
 81typedef struct svc_fh {
 82	struct knfsd_fh		fh_handle;	/* FH data */
 83	int			fh_maxsize;	/* max size for fh_handle */
 84	struct dentry *		fh_dentry;	/* validated dentry */
 85	struct svc_export *	fh_export;	/* export pointer */
 86
 87	bool			fh_want_write;	/* remount protection taken */
 88	bool			fh_no_wcc;	/* no wcc data needed */
 89	bool			fh_no_atomic_attr;
 90						/*
 91						 * wcc data is not atomic with
 92						 * operation
 93						 */
 94	bool			fh_use_wgather;	/* NFSv2 wgather option */
 95	bool			fh_64bit_cookies;/* readdir cookie size */
 96	int			fh_flags;	/* FH flags */
 97	bool			fh_post_saved;	/* post-op attrs saved */
 98	bool			fh_pre_saved;	/* pre-op attrs saved */
 99
100	/* Pre-op attributes saved when inode is locked */
101	__u64			fh_pre_size;	/* size before operation */
102	struct timespec64	fh_pre_mtime;	/* mtime before oper */
103	struct timespec64	fh_pre_ctime;	/* ctime before oper */
104	/*
105	 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
106	 *  to find out if it is valid.
107	 */
108	u64			fh_pre_change;
109
110	/* Post-op attributes saved in fh_fill_post_attrs() */
111	struct kstat		fh_post_attr;	/* full attrs after operation */
112	u64			fh_post_change; /* nfsv4 change; see above */
113} svc_fh;
114#define NFSD4_FH_FOREIGN (1<<0)
115#define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
116#define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
117
118enum nfsd_fsid {
119	FSID_DEV = 0,
120	FSID_NUM,
121	FSID_MAJOR_MINOR,
122	FSID_ENCODE_DEV,
123	FSID_UUID4_INUM,
124	FSID_UUID8,
125	FSID_UUID16,
126	FSID_UUID16_INUM,
127};
128
129enum fsid_source {
130	FSIDSOURCE_DEV,
131	FSIDSOURCE_FSID,
132	FSIDSOURCE_UUID,
133};
134extern enum fsid_source fsid_source(const struct svc_fh *fhp);
135
136
137/*
138 * This might look a little large to "inline" but in all calls except
139 * one, 'vers' is constant so moste of the function disappears.
140 *
141 * In some cases the values are considered to be host endian and in
142 * others, net endian. fsidv is always considered to be u32 as the
143 * callers don't know which it will be. So we must use __force to keep
144 * sparse from complaining. Since these values are opaque to the
145 * client, that shouldn't be a problem.
146 */
147static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
148			   u32 fsid, unsigned char *uuid)
149{
150	u32 *up;
151	switch(vers) {
152	case FSID_DEV:
153		fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
154				 MINOR(dev));
155		fsidv[1] = ino_t_to_u32(ino);
156		break;
157	case FSID_NUM:
158		fsidv[0] = fsid;
159		break;
160	case FSID_MAJOR_MINOR:
161		fsidv[0] = (__force __u32)htonl(MAJOR(dev));
162		fsidv[1] = (__force __u32)htonl(MINOR(dev));
163		fsidv[2] = ino_t_to_u32(ino);
164		break;
165
166	case FSID_ENCODE_DEV:
167		fsidv[0] = new_encode_dev(dev);
168		fsidv[1] = ino_t_to_u32(ino);
169		break;
170
171	case FSID_UUID4_INUM:
172		/* 4 byte fsid and inode number */
173		up = (u32*)uuid;
174		fsidv[0] = ino_t_to_u32(ino);
175		fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
176		break;
177
178	case FSID_UUID8:
179		/* 8 byte fsid  */
180		up = (u32*)uuid;
181		fsidv[0] = up[0] ^ up[2];
182		fsidv[1] = up[1] ^ up[3];
183		break;
184
185	case FSID_UUID16:
186		/* 16 byte fsid - NFSv3+ only */
187		memcpy(fsidv, uuid, 16);
188		break;
189
190	case FSID_UUID16_INUM:
191		/* 8 byte inode and 16 byte fsid */
192		*(u64*)fsidv = (u64)ino;
193		memcpy(fsidv+2, uuid, 16);
194		break;
195	default: BUG();
196	}
197}
198
199static inline int key_len(int type)
200{
201	switch(type) {
202	case FSID_DEV:		return 8;
203	case FSID_NUM: 		return 4;
204	case FSID_MAJOR_MINOR:	return 12;
205	case FSID_ENCODE_DEV:	return 8;
206	case FSID_UUID4_INUM:	return 8;
207	case FSID_UUID8:	return 8;
208	case FSID_UUID16:	return 16;
209	case FSID_UUID16_INUM:	return 24;
210	default: return 0;
211	}
212}
213
214/*
215 * Shorthand for dprintk()'s
216 */
217extern char * SVCFH_fmt(struct svc_fh *fhp);
218
219/*
220 * Function prototypes
221 */
222__be32	fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
223__be32	fh_verify_local(struct net *, struct svc_cred *, struct auth_domain *,
224			struct svc_fh *, umode_t, int);
225__be32	fh_getattr(const struct svc_fh *fhp, struct kstat *stat);
226__be32	fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
227__be32	fh_update(struct svc_fh *);
228void	fh_put(struct svc_fh *);
229
230static __inline__ struct svc_fh *
231fh_copy(struct svc_fh *dst, const struct svc_fh *src)
232{
233	WARN_ON(src->fh_dentry);
234
235	*dst = *src;
236	return dst;
237}
238
239static inline void
240fh_copy_shallow(struct knfsd_fh *dst, const struct knfsd_fh *src)
241{
242	dst->fh_size = src->fh_size;
243	memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size);
244}
245
246static __inline__ struct svc_fh *
247fh_init(struct svc_fh *fhp, int maxsize)
248{
249	memset(fhp, 0, sizeof(*fhp));
250	fhp->fh_maxsize = maxsize;
251	return fhp;
252}
253
254static inline bool fh_match(const struct knfsd_fh *fh1,
255			    const struct knfsd_fh *fh2)
256{
257	if (fh1->fh_size != fh2->fh_size)
258		return false;
259	if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0)
260		return false;
261	return true;
262}
263
264static inline bool fh_fsid_match(const struct knfsd_fh *fh1,
265				 const struct knfsd_fh *fh2)
266{
267	u32 *fsid1 = fh_fsid(fh1);
268	u32 *fsid2 = fh_fsid(fh2);
269
270	if (fh1->fh_fsid_type != fh2->fh_fsid_type)
271		return false;
272	if (memcmp(fsid1, fsid2, key_len(fh1->fh_fsid_type)) != 0)
273		return false;
274	return true;
275}
276
277/**
278 * fh_want_write - Get write access to an export
279 * @fhp: File handle of file to be written
280 *
281 * Caller must invoke fh_drop_write() when its write operation
282 * is complete.
283 *
284 * Returns 0 if the file handle's export can be written to. Otherwise
285 * the export is not prepared for updates, and the returned negative
286 * errno value reflects the reason for the failure.
287 */
288static inline int fh_want_write(struct svc_fh *fhp)
289{
290	int ret;
291
292	if (fhp->fh_want_write)
293		return 0;
294	ret = mnt_want_write(fhp->fh_export->ex_path.mnt);
295	if (!ret)
296		fhp->fh_want_write = true;
297	return ret;
298}
299
300/**
301 * fh_drop_write - Release write access on an export
302 * @fhp: File handle of file on which fh_want_write() was previously called
303 */
304static inline void fh_drop_write(struct svc_fh *fhp)
305{
306	if (fhp->fh_want_write) {
307		fhp->fh_want_write = false;
308		mnt_drop_write(fhp->fh_export->ex_path.mnt);
309	}
310}
311
312/**
313 * knfsd_fh_hash - calculate the crc32 hash for the filehandle
314 * @fh - pointer to filehandle
315 *
316 * returns a crc32 hash for the filehandle that is compatible with
317 * the one displayed by "wireshark".
318 */
319static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
320{
321	return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size);
322}
323
324/**
325 * fh_clear_pre_post_attrs - Reset pre/post attributes
326 * @fhp: file handle to be updated
327 *
328 */
329static inline void fh_clear_pre_post_attrs(struct svc_fh *fhp)
330{
331	fhp->fh_post_saved = false;
332	fhp->fh_pre_saved = false;
333}
334
335u64 nfsd4_change_attribute(const struct kstat *stat);
336__be32 __must_check fh_fill_pre_attrs(struct svc_fh *fhp);
337__be32 fh_fill_post_attrs(struct svc_fh *fhp);
338__be32 __must_check fh_fill_both_attrs(struct svc_fh *fhp);
339#endif /* _LINUX_NFSD_NFSFH_H */