xref: /linux/fs/smb/client/dfs.h (revision 2b753053980339a25d7ccc717b879f64e6a1cbea)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (c) 2022 Paulo Alcantara <palcantara@suse.de>
4  */
5 
6 #ifndef _CIFS_DFS_H
7 #define _CIFS_DFS_H
8 
9 #include "cifsglob.h"
10 #include "cifsproto.h"
11 #include "fs_context.h"
12 #include "dfs_cache.h"
13 #include "cifs_unicode.h"
14 #include <linux/namei.h>
15 #include <linux/errno.h>
16 
17 #define DFS_INTERLINK(v) \
18 	(((v) & DFSREF_REFERRAL_SERVER) && !((v) & DFSREF_STORAGE_SERVER))
19 
20 struct dfs_ref {
21 	char *path;
22 	char *full_path;
23 	struct cifs_ses *ses;
24 	struct dfs_cache_tgt_list tl;
25 	struct dfs_cache_tgt_iterator *tit;
26 };
27 
28 struct dfs_ref_walk {
29 	struct cifs_mount_ctx	*mnt_ctx;
30 	struct dfs_ref		*ref;
31 	struct dfs_ref		refs[MAX_NESTED_LINKS];
32 };
33 
34 #define ref_walk_start(w)	((w)->refs)
35 #define ref_walk_end(w)	(&(w)->refs[ARRAY_SIZE((w)->refs) - 1])
36 #define ref_walk_cur(w)	((w)->ref)
37 #define ref_walk_descend(w)	(--ref_walk_cur(w) >= ref_walk_start(w))
38 
39 #define ref_walk_tit(w)	(ref_walk_cur(w)->tit)
40 #define ref_walk_path(w)	(ref_walk_cur(w)->path)
41 #define ref_walk_fpath(w)	(ref_walk_cur(w)->full_path)
42 #define ref_walk_tl(w)		(&ref_walk_cur(w)->tl)
43 #define ref_walk_ses(w)	(ref_walk_cur(w)->ses)
44 
ref_walk_alloc(void)45 static inline struct dfs_ref_walk *ref_walk_alloc(void)
46 {
47 	struct dfs_ref_walk *rw;
48 
49 	rw = kmalloc(sizeof(*rw), GFP_KERNEL);
50 	if (!rw)
51 		return ERR_PTR(-ENOMEM);
52 	return rw;
53 }
54 
ref_walk_init(struct dfs_ref_walk * rw,struct cifs_mount_ctx * mnt_ctx)55 static inline void ref_walk_init(struct dfs_ref_walk *rw,
56 				 struct cifs_mount_ctx *mnt_ctx)
57 {
58 	memset(rw, 0, sizeof(*rw));
59 	rw->mnt_ctx = mnt_ctx;
60 	ref_walk_cur(rw) = ref_walk_start(rw);
61 }
62 
__ref_walk_free(struct dfs_ref * ref)63 static inline void __ref_walk_free(struct dfs_ref *ref)
64 {
65 	kfree(ref->path);
66 	kfree(ref->full_path);
67 	dfs_cache_free_tgts(&ref->tl);
68 	if (ref->ses)
69 		cifs_put_smb_ses(ref->ses);
70 	memset(ref, 0, sizeof(*ref));
71 }
72 
ref_walk_free(struct dfs_ref_walk * rw)73 static inline void ref_walk_free(struct dfs_ref_walk *rw)
74 {
75 	struct dfs_ref *ref;
76 
77 	if (!rw)
78 		return;
79 
80 	for (ref = ref_walk_start(rw); ref <= ref_walk_end(rw); ref++)
81 		__ref_walk_free(ref);
82 	kfree(rw);
83 }
84 
ref_walk_advance(struct dfs_ref_walk * rw)85 static inline int ref_walk_advance(struct dfs_ref_walk *rw)
86 {
87 	struct dfs_ref *ref = ref_walk_cur(rw) + 1;
88 
89 	if (ref > ref_walk_end(rw))
90 		return -ELOOP;
91 	__ref_walk_free(ref);
92 	ref_walk_cur(rw) = ref;
93 	return 0;
94 }
95 
96 static inline struct dfs_cache_tgt_iterator *
ref_walk_next_tgt(struct dfs_ref_walk * rw)97 ref_walk_next_tgt(struct dfs_ref_walk *rw)
98 {
99 	struct dfs_ref *ref = ref_walk_cur(rw);
100 	struct dfs_cache_tgt_iterator *tit;
101 
102 	if (IS_ERR(ref->tit))
103 		return NULL;
104 
105 	if (!ref->tit)
106 		tit = dfs_cache_get_tgt_iterator(&ref->tl);
107 	else
108 		tit = dfs_cache_get_next_tgt(&ref->tl, ref->tit);
109 
110 	if (!tit) {
111 		ref->tit = ERR_PTR(-ENOENT);
112 		return NULL;
113 	}
114 	ref->tit = tit;
115 	return ref->tit;
116 }
117 
ref_walk_get_tgt(struct dfs_ref_walk * rw,struct dfs_info3_param * tgt)118 static inline int ref_walk_get_tgt(struct dfs_ref_walk *rw,
119 				   struct dfs_info3_param *tgt)
120 {
121 	zfree_dfs_info_param(tgt);
122 	return dfs_cache_get_tgt_referral(ref_walk_path(rw) + 1,
123 					  ref_walk_tit(rw), tgt);
124 }
125 
ref_walk_set_tgt_hint(struct dfs_ref_walk * rw)126 static inline void ref_walk_set_tgt_hint(struct dfs_ref_walk *rw)
127 {
128 	dfs_cache_noreq_update_tgthint(ref_walk_path(rw) + 1,
129 				       ref_walk_tit(rw));
130 }
131 
ref_walk_set_tcon(struct dfs_ref_walk * rw,struct cifs_tcon * tcon)132 static inline void ref_walk_set_tcon(struct dfs_ref_walk *rw,
133 				     struct cifs_tcon *tcon)
134 {
135 	struct dfs_ref *ref = ref_walk_start(rw);
136 
137 	for (; ref <= ref_walk_cur(rw); ref++) {
138 		if (WARN_ON_ONCE(!ref->ses))
139 			continue;
140 		list_add(&ref->ses->dlist, &tcon->dfs_ses_list);
141 		ref->ses = NULL;
142 	}
143 }
144 
ref_walk_mark_end(struct dfs_ref_walk * rw)145 static inline void ref_walk_mark_end(struct dfs_ref_walk *rw)
146 {
147 	struct dfs_ref *ref = ref_walk_cur(rw) - 1;
148 
149 	WARN_ON_ONCE(ref < ref_walk_start(rw));
150 	dfs_cache_noreq_update_tgthint(ref->path + 1, ref->tit);
151 	ref->tit = ERR_PTR(-ENOENT); /* end marker */
152 }
153 
154 int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,
155 			      struct smb3_fs_context *ctx);
156 int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx);
157 
dfs_get_path(struct cifs_sb_info * cifs_sb,const char * path)158 static inline char *dfs_get_path(struct cifs_sb_info *cifs_sb, const char *path)
159 {
160 	return dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));
161 }
162 
dfs_get_referral(struct cifs_mount_ctx * mnt_ctx,const char * path,struct dfs_cache_tgt_list * tl)163 static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx,
164 				   const char *path,
165 				   struct dfs_cache_tgt_list *tl)
166 {
167 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
168 	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
169 	struct cifs_ses *rses = ctx->dfs_root_ses ?: mnt_ctx->ses;
170 
171 	return dfs_cache_find(mnt_ctx->xid, rses, cifs_sb->local_nls,
172 			      cifs_remap(cifs_sb), path, NULL, tl);
173 }
174 
175 /*
176  * cifs_get_smb_ses() already guarantees an active reference of
177  * @ses->dfs_root_ses when a new session is created, so we need to put extra
178  * references of all DFS root sessions that were used across the mount process
179  * in dfs_mount_share().
180  */
dfs_put_root_smb_sessions(struct list_head * head)181 static inline void dfs_put_root_smb_sessions(struct list_head *head)
182 {
183 	struct cifs_ses *ses, *n;
184 
185 	list_for_each_entry_safe(ses, n, head, dlist) {
186 		list_del_init(&ses->dlist);
187 		cifs_put_smb_ses(ses);
188 	}
189 }
190 
dfs_ses_refpath(struct cifs_ses * ses)191 static inline const char *dfs_ses_refpath(struct cifs_ses *ses)
192 {
193 	const char *path = ses->server->leaf_fullpath;
194 
195 	return path ? path + 1 : ERR_PTR(-ENOENT);
196 }
197 
198 #endif /* _CIFS_DFS_H */
199