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 <uapi/linux/nfsd/nfsfh.h>
14 #include <linux/iversion.h>
15 
ino_t_to_u32(ino_t ino)16 static inline __u32 ino_t_to_u32(ino_t ino)
17 {
18 	return (__u32) ino;
19 }
20 
u32_to_ino_t(__u32 uino)21 static inline ino_t u32_to_ino_t(__u32 uino)
22 {
23 	return (ino_t) uino;
24 }
25 
26 /*
27  * This is the internal representation of an NFS handle used in knfsd.
28  * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
29  */
30 typedef struct svc_fh {
31 	struct knfsd_fh		fh_handle;	/* FH data */
32 	int			fh_maxsize;	/* max size for fh_handle */
33 	struct dentry *		fh_dentry;	/* validated dentry */
34 	struct svc_export *	fh_export;	/* export pointer */
35 
36 	bool			fh_locked;	/* inode locked by us */
37 	bool			fh_want_write;	/* remount protection taken */
38 
39 #ifdef CONFIG_NFSD_V3
40 	bool			fh_post_saved;	/* post-op attrs saved */
41 	bool			fh_pre_saved;	/* pre-op attrs saved */
42 
43 	/* Pre-op attributes saved during fh_lock */
44 	__u64			fh_pre_size;	/* size before operation */
45 	struct timespec		fh_pre_mtime;	/* mtime before oper */
46 	struct timespec		fh_pre_ctime;	/* ctime before oper */
47 	/*
48 	 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
49 	 *  to find out if it is valid.
50 	 */
51 	u64			fh_pre_change;
52 
53 	/* Post-op attributes saved in fh_unlock */
54 	struct kstat		fh_post_attr;	/* full attrs after operation */
55 	u64			fh_post_change; /* nfsv4 change; see above */
56 #endif /* CONFIG_NFSD_V3 */
57 
58 } svc_fh;
59 
60 enum nfsd_fsid {
61 	FSID_DEV = 0,
62 	FSID_NUM,
63 	FSID_MAJOR_MINOR,
64 	FSID_ENCODE_DEV,
65 	FSID_UUID4_INUM,
66 	FSID_UUID8,
67 	FSID_UUID16,
68 	FSID_UUID16_INUM,
69 };
70 
71 enum fsid_source {
72 	FSIDSOURCE_DEV,
73 	FSIDSOURCE_FSID,
74 	FSIDSOURCE_UUID,
75 };
76 extern enum fsid_source fsid_source(struct svc_fh *fhp);
77 
78 
79 /*
80  * This might look a little large to "inline" but in all calls except
81  * one, 'vers' is constant so moste of the function disappears.
82  *
83  * In some cases the values are considered to be host endian and in
84  * others, net endian. fsidv is always considered to be u32 as the
85  * callers don't know which it will be. So we must use __force to keep
86  * sparse from complaining. Since these values are opaque to the
87  * client, that shouldn't be a problem.
88  */
mk_fsid(int vers,u32 * fsidv,dev_t dev,ino_t ino,u32 fsid,unsigned char * uuid)89 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
90 			   u32 fsid, unsigned char *uuid)
91 {
92 	u32 *up;
93 	switch(vers) {
94 	case FSID_DEV:
95 		fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
96 				 MINOR(dev));
97 		fsidv[1] = ino_t_to_u32(ino);
98 		break;
99 	case FSID_NUM:
100 		fsidv[0] = fsid;
101 		break;
102 	case FSID_MAJOR_MINOR:
103 		fsidv[0] = (__force __u32)htonl(MAJOR(dev));
104 		fsidv[1] = (__force __u32)htonl(MINOR(dev));
105 		fsidv[2] = ino_t_to_u32(ino);
106 		break;
107 
108 	case FSID_ENCODE_DEV:
109 		fsidv[0] = new_encode_dev(dev);
110 		fsidv[1] = ino_t_to_u32(ino);
111 		break;
112 
113 	case FSID_UUID4_INUM:
114 		/* 4 byte fsid and inode number */
115 		up = (u32*)uuid;
116 		fsidv[0] = ino_t_to_u32(ino);
117 		fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
118 		break;
119 
120 	case FSID_UUID8:
121 		/* 8 byte fsid  */
122 		up = (u32*)uuid;
123 		fsidv[0] = up[0] ^ up[2];
124 		fsidv[1] = up[1] ^ up[3];
125 		break;
126 
127 	case FSID_UUID16:
128 		/* 16 byte fsid - NFSv3+ only */
129 		memcpy(fsidv, uuid, 16);
130 		break;
131 
132 	case FSID_UUID16_INUM:
133 		/* 8 byte inode and 16 byte fsid */
134 		*(u64*)fsidv = (u64)ino;
135 		memcpy(fsidv+2, uuid, 16);
136 		break;
137 	default: BUG();
138 	}
139 }
140 
key_len(int type)141 static inline int key_len(int type)
142 {
143 	switch(type) {
144 	case FSID_DEV:		return 8;
145 	case FSID_NUM: 		return 4;
146 	case FSID_MAJOR_MINOR:	return 12;
147 	case FSID_ENCODE_DEV:	return 8;
148 	case FSID_UUID4_INUM:	return 8;
149 	case FSID_UUID8:	return 8;
150 	case FSID_UUID16:	return 16;
151 	case FSID_UUID16_INUM:	return 24;
152 	default: return 0;
153 	}
154 }
155 
156 /*
157  * Shorthand for dprintk()'s
158  */
159 extern char * SVCFH_fmt(struct svc_fh *fhp);
160 
161 /*
162  * Function prototypes
163  */
164 __be32	fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
165 __be32	fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
166 __be32	fh_update(struct svc_fh *);
167 void	fh_put(struct svc_fh *);
168 
169 static __inline__ struct svc_fh *
fh_copy(struct svc_fh * dst,struct svc_fh * src)170 fh_copy(struct svc_fh *dst, struct svc_fh *src)
171 {
172 	WARN_ON(src->fh_dentry || src->fh_locked);
173 
174 	*dst = *src;
175 	return dst;
176 }
177 
178 static inline void
fh_copy_shallow(struct knfsd_fh * dst,struct knfsd_fh * src)179 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
180 {
181 	dst->fh_size = src->fh_size;
182 	memcpy(&dst->fh_base, &src->fh_base, src->fh_size);
183 }
184 
185 static __inline__ struct svc_fh *
fh_init(struct svc_fh * fhp,int maxsize)186 fh_init(struct svc_fh *fhp, int maxsize)
187 {
188 	memset(fhp, 0, sizeof(*fhp));
189 	fhp->fh_maxsize = maxsize;
190 	return fhp;
191 }
192 
fh_match(struct knfsd_fh * fh1,struct knfsd_fh * fh2)193 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
194 {
195 	if (fh1->fh_size != fh2->fh_size)
196 		return false;
197 	if (memcmp(fh1->fh_base.fh_pad, fh2->fh_base.fh_pad, fh1->fh_size) != 0)
198 		return false;
199 	return true;
200 }
201 
fh_fsid_match(struct knfsd_fh * fh1,struct knfsd_fh * fh2)202 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
203 {
204 	if (fh1->fh_fsid_type != fh2->fh_fsid_type)
205 		return false;
206 	if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
207 		return false;
208 	return true;
209 }
210 
211 #ifdef CONFIG_CRC32
212 /**
213  * knfsd_fh_hash - calculate the crc32 hash for the filehandle
214  * @fh - pointer to filehandle
215  *
216  * returns a crc32 hash for the filehandle that is compatible with
217  * the one displayed by "wireshark".
218  */
219 
220 static inline u32
knfsd_fh_hash(struct knfsd_fh * fh)221 knfsd_fh_hash(struct knfsd_fh *fh)
222 {
223 	return ~crc32_le(0xFFFFFFFF, (unsigned char *)&fh->fh_base, fh->fh_size);
224 }
225 #else
226 static inline u32
knfsd_fh_hash(struct knfsd_fh * fh)227 knfsd_fh_hash(struct knfsd_fh *fh)
228 {
229 	return 0;
230 }
231 #endif
232 
233 #ifdef CONFIG_NFSD_V3
234 /*
235  * The wcc data stored in current_fh should be cleared
236  * between compound ops.
237  */
238 static inline void
fh_clear_wcc(struct svc_fh * fhp)239 fh_clear_wcc(struct svc_fh *fhp)
240 {
241 	fhp->fh_post_saved = false;
242 	fhp->fh_pre_saved = false;
243 }
244 
245 /*
246  * We could use i_version alone as the change attribute.  However,
247  * i_version can go backwards after a reboot.  On its own that doesn't
248  * necessarily cause a problem, but if i_version goes backwards and then
249  * is incremented again it could reuse a value that was previously used
250  * before boot, and a client who queried the two values might
251  * incorrectly assume nothing changed.
252  *
253  * By using both ctime and the i_version counter we guarantee that as
254  * long as time doesn't go backwards we never reuse an old value.
255  */
nfsd4_change_attribute(struct kstat * stat,struct inode * inode)256 static inline u64 nfsd4_change_attribute(struct kstat *stat,
257 					 struct inode *inode)
258 {
259 	u64 chattr;
260 
261 	chattr =  stat->ctime.tv_sec;
262 	chattr <<= 30;
263 	chattr += stat->ctime.tv_nsec;
264 	chattr += inode_query_iversion(inode);
265 	return chattr;
266 }
267 
268 extern void fill_pre_wcc(struct svc_fh *fhp);
269 extern void fill_post_wcc(struct svc_fh *fhp);
270 #else
271 #define fh_clear_wcc(ignored)
272 #define fill_pre_wcc(ignored)
273 #define fill_post_wcc(notused)
274 #endif /* CONFIG_NFSD_V3 */
275 
276 
277 /*
278  * Lock a file handle/inode
279  * NOTE: both fh_lock and fh_unlock are done "by hand" in
280  * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
281  * so, any changes here should be reflected there.
282  */
283 
284 static inline void
fh_lock_nested(struct svc_fh * fhp,unsigned int subclass)285 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
286 {
287 	struct dentry	*dentry = fhp->fh_dentry;
288 	struct inode	*inode;
289 
290 	BUG_ON(!dentry);
291 
292 	if (fhp->fh_locked) {
293 		printk(KERN_WARNING "fh_lock: %pd2 already locked!\n",
294 			dentry);
295 		return;
296 	}
297 
298 	inode = d_inode(dentry);
299 	inode_lock_nested(inode, subclass);
300 	fill_pre_wcc(fhp);
301 	fhp->fh_locked = true;
302 }
303 
304 static inline void
fh_lock(struct svc_fh * fhp)305 fh_lock(struct svc_fh *fhp)
306 {
307 	fh_lock_nested(fhp, I_MUTEX_NORMAL);
308 }
309 
310 /*
311  * Unlock a file handle/inode
312  */
313 static inline void
fh_unlock(struct svc_fh * fhp)314 fh_unlock(struct svc_fh *fhp)
315 {
316 	if (fhp->fh_locked) {
317 		fill_post_wcc(fhp);
318 		inode_unlock(d_inode(fhp->fh_dentry));
319 		fhp->fh_locked = false;
320 	}
321 }
322 
323 #endif /* _LINUX_NFSD_NFSFH_H */
324