source: vendor/current/source3/smbd/oplock_linux.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 6.8 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3 kernel oplock processing for Linux
4 Copyright (C) Andrew Tridgell 2000
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
18*/
19
20#define DBGC_CLASS DBGC_LOCKING
21#include "includes.h"
22#include "system/filesys.h"
23#include "smbd/smbd.h"
24#include "smbd/globals.h"
25
26#if HAVE_KERNEL_OPLOCKS_LINUX
27
28#ifndef F_SETLEASE
29#define F_SETLEASE 1024
30#endif
31
32#ifndef F_GETLEASE
33#define F_GETLEASE 1025
34#endif
35
36#ifndef CAP_LEASE
37#define CAP_LEASE 28
38#endif
39
40#ifndef RT_SIGNAL_LEASE
41#define RT_SIGNAL_LEASE (SIGRTMIN+1)
42#endif
43
44#ifndef F_SETSIG
45#define F_SETSIG 10
46#endif
47
48/*
49 * public function to get linux lease capability. Needed by some VFS modules (eg. gpfs.c)
50 */
51void linux_set_lease_capability(void)
52{
53 set_effective_capability(LEASE_CAPABILITY);
54}
55
56/*
57 * Call to set the kernel lease signal handler
58 */
59int linux_set_lease_sighandler(int fd)
60{
61 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
62 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
63 return -1;
64 }
65
66 return 0;
67}
68
69/****************************************************************************
70 Call SETLEASE. If we get EACCES then we try setting up the right capability and
71 try again.
72 Use the SMB_VFS_LINUX_SETLEASE instead of this call directly.
73****************************************************************************/
74
75int linux_setlease(int fd, int leasetype)
76{
77 int ret;
78 int saved_errno;
79
80 /*
81 * Ensure the lease owner is root to allow
82 * correct delivery of lease-break signals.
83 */
84
85 become_root();
86
87 /* First set the signal handler. */
88 if (linux_set_lease_sighandler(fd) == -1) {
89 saved_errno = errno;
90 ret = -1;
91 goto out;
92 }
93 ret = fcntl(fd, F_SETLEASE, leasetype);
94 if (ret == -1) {
95 saved_errno = errno;
96 }
97
98 out:
99
100 unbecome_root();
101
102 if (ret == -1) {
103 errno = saved_errno;
104 }
105 return ret;
106}
107
108/****************************************************************************
109 * Deal with the Linux kernel <--> smbd
110 * oplock break protocol.
111****************************************************************************/
112
113static void linux_oplock_signal_handler(struct tevent_context *ev_ctx,
114 struct tevent_signal *se,
115 int signum, int count,
116 void *_info, void *private_data)
117{
118 struct kernel_oplocks *ctx =
119 talloc_get_type_abort(private_data,
120 struct kernel_oplocks);
121 struct smbd_server_connection *sconn =
122 talloc_get_type_abort(ctx->private_data,
123 struct smbd_server_connection);
124 siginfo_t *info = (siginfo_t *)_info;
125 int fd = info->si_fd;
126 files_struct *fsp;
127
128 fsp = file_find_fd(sconn, fd);
129 if (fsp == NULL) {
130 DEBUG(0,("linux_oplock_signal_handler: failed to find fsp for file fd=%d (file was closed ?)\n", fd ));
131 return;
132 }
133 break_kernel_oplock(sconn->msg_ctx, fsp);
134}
135
136/****************************************************************************
137 Attempt to set an kernel oplock on a file.
138****************************************************************************/
139
140static bool linux_set_kernel_oplock(struct kernel_oplocks *ctx,
141 files_struct *fsp, int oplock_type)
142{
143 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) {
144 DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, "
145 "fd = %d, file_id = %s. (%s)\n",
146 fsp_str_dbg(fsp), fsp->fh->fd,
147 file_id_string_tos(&fsp->file_id),
148 strerror(errno)));
149 return False;
150 }
151
152 DEBUG(3,("linux_set_kernel_oplock: got kernel oplock on file %s, "
153 "file_id = %s gen_id = %lu\n",
154 fsp_str_dbg(fsp), file_id_string_tos(&fsp->file_id),
155 fsp->fh->gen_id));
156
157 return True;
158}
159
160/****************************************************************************
161 Release a kernel oplock on a file.
162****************************************************************************/
163
164static void linux_release_kernel_oplock(struct kernel_oplocks *ctx,
165 files_struct *fsp, int oplock_type)
166{
167 if (DEBUGLVL(10)) {
168 /*
169 * Check and print out the current kernel
170 * oplock state of this file.
171 */
172 int state = fcntl(fsp->fh->fd, F_GETLEASE, 0);
173 dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
174 "gen_id = %lu has kernel oplock state "
175 "of %x.\n", fsp_str_dbg(fsp),
176 file_id_string_tos(&fsp->file_id),
177 fsp->fh->gen_id, state );
178 }
179
180 /*
181 * Remove the kernel oplock on this file.
182 */
183 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) {
184 if (DEBUGLVL(0)) {
185 dbgtext("linux_release_kernel_oplock: Error when "
186 "removing kernel oplock on file " );
187 dbgtext("%s, file_id = %s, gen_id = %lu. "
188 "Error was %s\n", fsp_str_dbg(fsp),
189 file_id_string_tos(&fsp->file_id),
190 fsp->fh->gen_id, strerror(errno) );
191 }
192 }
193}
194
195/****************************************************************************
196 See if the kernel supports oplocks.
197****************************************************************************/
198
199static bool linux_oplocks_available(void)
200{
201 int fd, ret;
202 fd = open("/dev/null", O_RDONLY);
203 if (fd == -1)
204 return False; /* uggh! */
205 ret = fcntl(fd, F_GETLEASE, 0);
206 close(fd);
207 return ret == F_UNLCK;
208}
209
210/****************************************************************************
211 Setup kernel oplocks.
212****************************************************************************/
213
214static const struct kernel_oplocks_ops linux_koplocks = {
215 .set_oplock = linux_set_kernel_oplock,
216 .release_oplock = linux_release_kernel_oplock,
217 .contend_level2_oplocks_begin = NULL,
218 .contend_level2_oplocks_end = NULL,
219};
220
221struct kernel_oplocks *linux_init_kernel_oplocks(struct smbd_server_connection *sconn)
222{
223 struct kernel_oplocks *ctx;
224 struct tevent_signal *se;
225
226 if (!linux_oplocks_available()) {
227 DEBUG(3,("Linux kernel oplocks not available\n"));
228 return NULL;
229 }
230
231 ctx = talloc_zero(sconn, struct kernel_oplocks);
232 if (!ctx) {
233 DEBUG(0,("Linux Kernel oplocks talloc_Zero failed\n"));
234 return NULL;
235 }
236
237 ctx->ops = &linux_koplocks;
238 ctx->private_data = sconn;
239
240 se = tevent_add_signal(sconn->ev_ctx,
241 ctx,
242 RT_SIGNAL_LEASE, SA_SIGINFO,
243 linux_oplock_signal_handler,
244 ctx);
245 if (!se) {
246 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler"));
247 TALLOC_FREE(ctx);
248 return NULL;
249 }
250
251 DEBUG(3,("Linux kernel oplocks enabled\n"));
252
253 return ctx;
254}
255#else
256 void oplock_linux_dummy(void);
257
258 void oplock_linux_dummy(void) {}
259#endif /* HAVE_KERNEL_OPLOCKS_LINUX */
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