1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/*
Copyright (C) 1994,95,96,97,98,99,2001,2003 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "priv.h"
/* Check if source directory is in the path of the target directory.
We get target locked, source unlocked but with a reference. When
we return, nothing is locked, and target has lost its reference.
This routine assumes that no renames of directories will happen
while it is running; as a result, ufs_rename serializes all renames
of directories. */
static error_t
checkpath(struct node *source,
struct node *target,
struct protid *cred)
{
error_t err;
struct node *np;
for (np = target, err = 0;
/* nothing */;
/* This special lookup does a diskfs_nput on its first argument
when it succeeds. */
err = diskfs_lookup (np, "..", LOOKUP | SPEC_DOTDOT, &np, 0, cred))
{
if (err)
{
diskfs_nput (np);
return err;
}
if (np == source)
{
diskfs_nput (np);
return EINVAL;
}
if (np == diskfs_root_node)
{
diskfs_nput (np);
return 0;
}
}
}
/* Rename directory node FNP (whose parent is FDP, and which has name
FROMNAME in that directory) to have name TONAME inside directory
TDP. None of these nodes are locked, and none should be locked
upon return. This routine is serialized, so it doesn't have to be
reentrant. Directories will never be renamed except by this
routine. FROMCRED and TOCRED are the users responsible for
FDP/FNP and TDP respectively. */
error_t
diskfs_rename_dir (struct node *fdp, struct node *fnp, const char *fromname,
struct node *tdp, const char *toname,
struct protid *fromcred, struct protid *tocred)
{
error_t err;
struct node *tnp, *tmpnp;
void *buf = alloca (diskfs_dirstat_size);
struct dirstat *ds;
struct dirstat *tmpds;
pthread_mutex_lock (&tdp->lock);
diskfs_nref (tdp); /* reference and lock will get consumed by
checkpath */
err = checkpath (fnp, tdp, tocred);
if (err)
return err;
/* Now, lock the parent directories. This is legal because tdp is not
a child of fnp (guaranteed by checkpath above). */
pthread_mutex_lock (&fdp->lock);
if (fdp != tdp)
pthread_mutex_lock (&tdp->lock);
/* 1: Lookup target; if it exists, make sure it's an empty directory. */
ds = buf;
err = diskfs_lookup (tdp, toname, RENAME, &tnp, ds, tocred);
assert (err != EAGAIN); /* <-> assert (TONAME != "..") */
if (tnp == fnp)
{
diskfs_drop_dirstat (tdp, ds);
diskfs_nput (tnp);
pthread_mutex_unlock (&tdp->lock);
if (fdp != tdp)
pthread_mutex_unlock (&fdp->lock);
return 0;
}
/* Check permissions to remove FROMNAME and lock FNP. */
tmpds = alloca (diskfs_dirstat_size);
err = diskfs_lookup (fdp, fromname, REMOVE, &tmpnp, tmpds, fromcred);
assert (!tmpnp || tmpnp == fnp);
if (tmpnp)
diskfs_nrele (tmpnp);
diskfs_drop_dirstat (fdp, tmpds);
if (err)
goto out;
if (tnp)
{
if (! S_ISDIR(tnp->dn_stat.st_mode))
err = ENOTDIR;
else if (!diskfs_dirempty (tnp, tocred))
err = ENOTEMPTY;
}
if (err && err != ENOENT)
goto out;
/* 2: Set our .. to point to the new parent */
if (fdp != tdp)
{
if (tdp->dn_stat.st_nlink == diskfs_link_max - 1)
{
err = EMLINK;
return EMLINK;
}
tdp->dn_stat.st_nlink++;
tdp->dn_set_ctime = 1;
if (diskfs_synchronous)
diskfs_node_update (tdp, 1);
tmpds = alloca (diskfs_dirstat_size);
err = diskfs_lookup (fnp, "..", RENAME | SPEC_DOTDOT,
&tmpnp, tmpds, fromcred);
assert (err != ENOENT);
if (err)
{
diskfs_drop_dirstat (fnp, tmpds);
goto out;
}
assert (tmpnp == fdp);
err = diskfs_dirrewrite (fnp, fdp, tdp, "..", tmpds);
if (diskfs_synchronous)
diskfs_file_update (fnp, 1);
if (err)
goto out;
fdp->dn_stat.st_nlink--;
fdp->dn_set_ctime = 1;
if (diskfs_synchronous)
diskfs_node_update (fdp, 1);
}
/* 3: Increment the link count on the node being moved and rewrite
tdp. */
if (fnp->dn_stat.st_nlink == diskfs_link_max - 1)
{
pthread_mutex_unlock (&fnp->lock);
diskfs_drop_dirstat (tdp, ds);
pthread_mutex_unlock (&tdp->lock);
if (tnp)
diskfs_nput (tnp);
return EMLINK;
}
fnp->dn_stat.st_nlink++;
fnp->dn_set_ctime = 1;
diskfs_node_update (fnp, diskfs_synchronous);
if (tnp)
{
err = diskfs_dirrewrite (tdp, tnp, fnp, toname, ds);
ds = 0;
if (!err)
{
tnp->dn_stat.st_nlink--;
tnp->dn_set_ctime = 1;
}
diskfs_clear_directory (tnp, tdp, tocred);
if (diskfs_synchronous)
diskfs_file_update (tnp, 1);
}
else
{
err = diskfs_direnter (tdp, toname, fnp, ds, tocred);
if (diskfs_synchronous)
diskfs_file_update (tdp, 1);
}
if (err)
goto out;
/* 4: Remove the entry in fdp. */
ds = buf;
pthread_mutex_unlock (&fnp->lock);
err = diskfs_lookup (fdp, fromname, REMOVE, &tmpnp, ds, fromcred);
assert (!tmpnp || tmpnp == fnp);
if (tmpnp)
diskfs_nrele (tmpnp);
if (err)
goto out;
diskfs_dirremove (fdp, fnp, fromname, ds);
ds = 0;
fnp->dn_stat.st_nlink--;
fnp->dn_set_ctime = 1;
if (diskfs_synchronous)
{
diskfs_file_update (fdp, 1);
diskfs_node_update (fnp, 1);
}
out:
if (tdp)
pthread_mutex_unlock (&tdp->lock);
if (tnp)
diskfs_nput (tnp);
if (fdp && fdp != tdp)
pthread_mutex_unlock (&fdp->lock);
if (fnp)
pthread_mutex_unlock (&fnp->lock);
if (ds)
diskfs_drop_dirstat (tdp, ds);
return err;
}
|
