source: branches/samba-3.5.x/source3/smbd/oplock_linux.c

Last change on this file was 736, checked in by Silvan Scherrer, 13 years ago

Samba Server 3.5: update branche to 3.5.16
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 "smbd/globals.h"
23
24#if HAVE_KERNEL_OPLOCKS_LINUX
25
26#ifndef F_SETLEASE
27#define F_SETLEASE 1024
28#endif
29
30#ifndef F_GETLEASE
31#define F_GETLEASE 1025
32#endif
33
34#ifndef CAP_LEASE
35#define CAP_LEASE 28
36#endif
37
38#ifndef RT_SIGNAL_LEASE
39#define RT_SIGNAL_LEASE (SIGRTMIN+1)
40#endif
41
42#ifndef F_SETSIG
43#define F_SETSIG 10
44#endif
45
46/*
47 * public function to get linux lease capability. Needed by some VFS modules (eg. gpfs.c)
48 */
49void linux_set_lease_capability(void)
50{
51 set_effective_capability(LEASE_CAPABILITY);
52}
53
54/*
55 * Call to set the kernel lease signal handler
56 */
57int linux_set_lease_sighandler(int fd)
58{
59 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
60 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
61 return -1;
62 }
63
64 return 0;
65}
66
67/****************************************************************************
68 Call SETLEASE. If we get EACCES then we try setting up the right capability and
69 try again.
70 Use the SMB_VFS_LINUX_SETLEASE instead of this call directly.
71****************************************************************************/
72
73int linux_setlease(int fd, int leasetype)
74{
75 int ret;
76
77 /* First set the signal handler. */
78 if (linux_set_lease_sighandler(fd) == -1) {
79 return -1;
80 }
81 ret = fcntl(fd, F_SETLEASE, leasetype);
82 if (ret == -1 && errno == EACCES) {
83 set_effective_capability(LEASE_CAPABILITY);
84 /*
85 * Bug 8974 - work around Linux kernel bug
86 * https://bugzilla.kernel.org/show_bug.cgi?id=43336.
87 * "fcntl(F_SETLEASE) resets signal number when
88 * called multiple times"
89 */
90 if (linux_set_lease_sighandler(fd) == -1) {
91 return -1;
92 }
93 ret = fcntl(fd, F_SETLEASE, leasetype);
94 }
95
96 return ret;
97}
98
99/****************************************************************************
100 * Deal with the Linux kernel <--> smbd
101 * oplock break protocol.
102****************************************************************************/
103
104static void linux_oplock_signal_handler(struct tevent_context *ev_ctx,
105 struct tevent_signal *se,
106 int signum, int count,
107 void *_info, void *private_data)
108{
109 siginfo_t *info = (siginfo_t *)_info;
110 int fd = info->si_fd;
111 files_struct *fsp;
112
113 fsp = file_find_fd(fd);
114 if (fsp == NULL) {
115 DEBUG(0,("linux_oplock_signal_handler: failed to find fsp for file fd=%d (file was closed ?)\n", fd ));
116 return;
117 }
118 break_kernel_oplock(smbd_messaging_context(), fsp);
119}
120
121/****************************************************************************
122 Attempt to set an kernel oplock on a file.
123****************************************************************************/
124
125static bool linux_set_kernel_oplock(struct kernel_oplocks *ctx,
126 files_struct *fsp, int oplock_type)
127{
128 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) {
129 DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, "
130 "fd = %d, file_id = %s. (%s)\n",
131 fsp_str_dbg(fsp), fsp->fh->fd,
132 file_id_string_tos(&fsp->file_id),
133 strerror(errno)));
134 return False;
135 }
136
137 DEBUG(3,("linux_set_kernel_oplock: got kernel oplock on file %s, "
138 "file_id = %s gen_id = %lu\n",
139 fsp_str_dbg(fsp), file_id_string_tos(&fsp->file_id),
140 fsp->fh->gen_id));
141
142 return True;
143}
144
145/****************************************************************************
146 Release a kernel oplock on a file.
147****************************************************************************/
148
149static void linux_release_kernel_oplock(struct kernel_oplocks *ctx,
150 files_struct *fsp, int oplock_type)
151{
152 if (DEBUGLVL(10)) {
153 /*
154 * Check and print out the current kernel
155 * oplock state of this file.
156 */
157 int state = fcntl(fsp->fh->fd, F_GETLEASE, 0);
158 dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
159 "gen_id = %lu has kernel oplock state "
160 "of %x.\n", fsp_str_dbg(fsp),
161 file_id_string_tos(&fsp->file_id),
162 fsp->fh->gen_id, state );
163 }
164
165 /*
166 * Remove the kernel oplock on this file.
167 */
168 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) {
169 if (DEBUGLVL(0)) {
170 dbgtext("linux_release_kernel_oplock: Error when "
171 "removing kernel oplock on file " );
172 dbgtext("%s, file_id = %s, gen_id = %lu. "
173 "Error was %s\n", fsp_str_dbg(fsp),
174 file_id_string_tos(&fsp->file_id),
175 fsp->fh->gen_id, strerror(errno) );
176 }
177 }
178}
179
180/****************************************************************************
181 See if the kernel supports oplocks.
182****************************************************************************/
183
184static bool linux_oplocks_available(void)
185{
186 int fd, ret;
187 fd = open("/dev/null", O_RDONLY);
188 if (fd == -1)
189 return False; /* uggh! */
190 ret = fcntl(fd, F_GETLEASE, 0);
191 close(fd);
192 return ret == F_UNLCK;
193}
194
195/****************************************************************************
196 Setup kernel oplocks.
197****************************************************************************/
198
199static const struct kernel_oplocks_ops linux_koplocks = {
200 .set_oplock = linux_set_kernel_oplock,
201 .release_oplock = linux_release_kernel_oplock,
202 .contend_level2_oplocks_begin = NULL,
203 .contend_level2_oplocks_end = NULL,
204};
205
206struct kernel_oplocks *linux_init_kernel_oplocks(TALLOC_CTX *mem_ctx)
207{
208 struct kernel_oplocks *ctx;
209 struct tevent_signal *se;
210
211 if (!linux_oplocks_available()) {
212 DEBUG(3,("Linux kernel oplocks not available\n"));
213 return NULL;
214 }
215
216 ctx = talloc_zero(mem_ctx, struct kernel_oplocks);
217 if (!ctx) {
218 DEBUG(0,("Linux Kernel oplocks talloc_Zero failed\n"));
219 return NULL;
220 }
221
222 ctx->ops = &linux_koplocks;
223
224 se = tevent_add_signal(smbd_event_context(),
225 ctx,
226 RT_SIGNAL_LEASE, SA_SIGINFO,
227 linux_oplock_signal_handler,
228 ctx);
229 if (!se) {
230 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler"));
231 TALLOC_FREE(ctx);
232 return NULL;
233 }
234
235 ctx->private_data = se;
236
237 DEBUG(3,("Linux kernel oplocks enabled\n"));
238
239 return ctx;
240}
241#else
242 void oplock_linux_dummy(void);
243
244 void oplock_linux_dummy(void) {}
245#endif /* HAVE_KERNEL_OPLOCKS_LINUX */
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