2 Unix SMB/CIFS implementation.
3 kernel oplock processing for Linux
4 Copyright (C) Andrew Tridgell 2000
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.
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.
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/>.
20 #define DBGC_CLASS DBGC_LOCKING
23 #if HAVE_KERNEL_OPLOCKS_LINUX
25 /* these can be removed when they are in glibc headers */
26 struct cap_user_header {
30 struct cap_user_data {
36 extern int capget(struct cap_user_header * hdrp,
37 struct cap_user_data * datap);
38 extern int capset(struct cap_user_header * hdrp,
39 const struct cap_user_data * datap);
41 static SIG_ATOMIC_T signals_received;
42 #define FD_PENDING_SIZE 100
43 static SIG_ATOMIC_T fd_pending_array[FD_PENDING_SIZE];
46 #define F_SETLEASE 1024
50 #define F_GETLEASE 1025
57 #ifndef RT_SIGNAL_LEASE
58 #define RT_SIGNAL_LEASE (SIGRTMIN+1)
65 /****************************************************************************
66 Handle a LEASE signal, incrementing the signals_received and blocking the signal.
67 ****************************************************************************/
69 static void signal_handler(int sig, siginfo_t *info, void *unused)
71 if (signals_received < FD_PENDING_SIZE - 1) {
72 fd_pending_array[signals_received] = (SIG_ATOMIC_T)info->si_fd;
74 } /* Else signal is lost. */
75 sys_select_signal(RT_SIGNAL_LEASE);
78 /****************************************************************************
79 Try to gain a linux capability.
80 ****************************************************************************/
82 static void set_capability(unsigned capability)
84 #ifndef _LINUX_CAPABILITY_VERSION
85 #define _LINUX_CAPABILITY_VERSION 0x19980330
87 header.version = _LINUX_CAPABILITY_VERSION;
90 if (capget(&header, &data) == -1) {
91 DEBUG(3,("Unable to get kernel capabilities (%s)\n",
96 data.effective |= (1<<capability);
98 if (capset(&header, &data) == -1) {
99 DEBUG(3,("Unable to set %d capability (%s)\n",
100 capability, strerror(errno)));
105 Call to set the kernel lease signal handler
107 int linux_set_lease_sighandler(int fd)
109 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
110 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
117 /****************************************************************************
118 Call SETLEASE. If we get EACCES then we try setting up the right capability and
120 Use the SMB_VFS_LINUX_SETLEASE instead of this call directly.
121 ****************************************************************************/
123 int linux_setlease(int fd, int leasetype)
127 ret = fcntl(fd, F_SETLEASE, leasetype);
128 if (ret == -1 && errno == EACCES) {
129 set_capability(CAP_LEASE);
130 ret = fcntl(fd, F_SETLEASE, leasetype);
136 /****************************************************************************
137 * Deal with the Linux kernel <--> smbd
138 * oplock break protocol.
139 ****************************************************************************/
141 static files_struct *linux_oplock_receive_message(fd_set *fds)
146 BlockSignals(True, RT_SIGNAL_LEASE);
147 fd = fd_pending_array[0];
148 fsp = file_find_fd(fd);
149 fd_pending_array[0] = (SIG_ATOMIC_T)-1;
150 if (signals_received > 1)
151 memmove(CONST_DISCARD(void *, &fd_pending_array[0]),
152 CONST_DISCARD(void *, &fd_pending_array[1]),
153 sizeof(SIG_ATOMIC_T)*(signals_received-1));
155 /* now we can receive more signals */
156 BlockSignals(False, RT_SIGNAL_LEASE);
161 /****************************************************************************
162 Attempt to set an kernel oplock on a file.
163 ****************************************************************************/
165 static bool linux_set_kernel_oplock(files_struct *fsp, int oplock_type)
167 if ( SMB_VFS_LINUX_SETLEASE(fsp,fsp->fh->fd, F_WRLCK) == -1) {
168 DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, "
169 "fd = %d, file_id = %s. (%s)\n",
170 fsp->fsp_name, fsp->fh->fd,
171 file_id_string_tos(&fsp->file_id),
176 DEBUG(3,("linux_set_kernel_oplock: got kernel oplock on file %s, "
177 "file_id = %s gen_id = %lu\n",
178 fsp->fsp_name, file_id_string_tos(&fsp->file_id),
184 /****************************************************************************
185 Release a kernel oplock on a file.
186 ****************************************************************************/
188 static void linux_release_kernel_oplock(files_struct *fsp)
192 * Check and print out the current kernel
193 * oplock state of this file.
195 int state = fcntl(fsp->fh->fd, F_GETLEASE, 0);
196 dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
197 "gen_id = %lu has kernel oplock state "
198 "of %x.\n", fsp->fsp_name, file_id_string_tos(&fsp->file_id),
199 fsp->fh->gen_id, state );
203 * Remove the kernel oplock on this file.
205 if ( SMB_VFS_LINUX_SETLEASE(fsp,fsp->fh->fd, F_UNLCK) == -1) {
207 dbgtext("linux_release_kernel_oplock: Error when "
208 "removing kernel oplock on file " );
209 dbgtext("%s, file_id = %s, gen_id = %lu. "
210 "Error was %s\n", fsp->fsp_name,
211 file_id_string_tos(&fsp->file_id),
212 fsp->fh->gen_id, strerror(errno) );
217 /****************************************************************************
218 See if a oplock message is waiting.
219 ****************************************************************************/
221 static bool linux_oplock_msg_waiting(fd_set *fds)
223 return signals_received != 0;
226 /****************************************************************************
227 See if the kernel supports oplocks.
228 ****************************************************************************/
230 static bool linux_oplocks_available(void)
233 fd = open("/dev/null", O_RDONLY);
235 return False; /* uggh! */
236 ret = fcntl(fd, F_GETLEASE, 0);
238 return ret == F_UNLCK;
241 /****************************************************************************
242 Setup kernel oplocks.
243 ****************************************************************************/
245 struct kernel_oplocks *linux_init_kernel_oplocks(void)
247 static struct kernel_oplocks koplocks;
248 struct sigaction act;
250 if (!linux_oplocks_available()) {
251 DEBUG(3,("Linux kernel oplocks not available\n"));
257 act.sa_handler = NULL;
258 act.sa_sigaction = signal_handler;
259 act.sa_flags = SA_SIGINFO;
260 sigemptyset( &act.sa_mask );
261 if (sigaction(RT_SIGNAL_LEASE, &act, NULL) != 0) {
262 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler\n"));
266 koplocks.receive_message = linux_oplock_receive_message;
267 koplocks.set_oplock = linux_set_kernel_oplock;
268 koplocks.release_oplock = linux_release_kernel_oplock;
269 koplocks.msg_waiting = linux_oplock_msg_waiting;
270 koplocks.notification_fd = -1;
272 /* the signal can start off blocked due to a bug in bash */
273 BlockSignals(False, RT_SIGNAL_LEASE);
275 DEBUG(3,("Linux kernel oplocks enabled\n"));
280 void oplock_linux_dummy(void);
282 void oplock_linux_dummy(void) {}
283 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */