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 2 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, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #if HAVE_KERNEL_OPLOCKS_LINUX
25 static VOLATILE sig_atomic_t signals_received;
26 static VOLATILE sig_atomic_t signals_processed;
27 static VOLATILE sig_atomic_t fd_pending; /* the fd of the current pending signal */
30 #define F_SETLEASE 1024
34 #define F_GETLEASE 1025
41 #ifndef RT_SIGNAL_LEASE
42 #define RT_SIGNAL_LEASE 33
49 /****************************************************************************
50 Handle a LEASE signal, incrementing the signals_received and blocking the signal.
51 ****************************************************************************/
53 static void signal_handler(int sig, siginfo_t *info, void *unused)
55 BlockSignals(True, sig);
56 fd_pending = (sig_atomic_t)info->si_fd;
61 /****************************************************************************
62 Try to gain a linux capability.
63 ****************************************************************************/
65 static void set_capability(unsigned capability)
67 #ifndef _LINUX_CAPABILITY_VERSION
68 #define _LINUX_CAPABILITY_VERSION 0x19980330
70 /* these can be removed when they are in glibc headers */
81 header.version = _LINUX_CAPABILITY_VERSION;
84 if (capget(&header, &data) == -1) {
85 DEBUG(3,("Unable to get kernel capabilities (%s)\n", strerror(errno)));
89 data.effective |= (1<<capability);
91 if (capset(&header, &data) == -1) {
92 DEBUG(3,("Unable to set %d capability (%s)\n",
93 capability, strerror(errno)));
97 /****************************************************************************
98 Call SETLEASE. If we get EACCES then we try setting up the right capability and
100 ****************************************************************************/
102 static int linux_setlease(int fd, int leasetype)
106 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
107 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
111 ret = fcntl(fd, F_SETLEASE, leasetype);
112 if (ret == -1 && errno == EACCES) {
113 set_capability(CAP_LEASE);
114 ret = fcntl(fd, F_SETLEASE, leasetype);
120 /****************************************************************************
121 * Deal with the Linux kernel <--> smbd
122 * oplock break protocol.
123 ****************************************************************************/
125 static BOOL linux_oplock_receive_message(fd_set *fds, char *buffer, int buffer_len)
128 struct files_struct *fsp;
130 if (signals_received == signals_processed)
133 if ((fsp = file_find_fd(fd_pending)) == NULL) {
134 DEBUG(0,("Invalid file descriptor %d in kernel oplock break!\n", (int)fd_pending));
139 DEBUG(3,("receive_local_message: kernel oplock break request received for \
140 dev = %x, inode = %.0f\n", (unsigned int)fsp->dev, (double)fsp->inode ));
143 * Create a kernel oplock break message.
146 /* Setup the message header */
147 SIVAL(buffer,OPBRK_CMD_LEN_OFFSET,KERNEL_OPLOCK_BREAK_MSG_LEN);
148 SSVAL(buffer,OPBRK_CMD_PORT_OFFSET,0);
150 buffer += OPBRK_CMD_HEADER_LEN;
152 SSVAL(buffer,OPBRK_MESSAGE_CMD_OFFSET,KERNEL_OPLOCK_BREAK_CMD);
154 memcpy(buffer + KERNEL_OPLOCK_BREAK_DEV_OFFSET, (char *)&fsp->dev, sizeof(fsp->dev));
155 memcpy(buffer + KERNEL_OPLOCK_BREAK_INODE_OFFSET, (char *)&fsp->inode, sizeof(fsp->inode));
156 memcpy(buffer + KERNEL_OPLOCK_BREAK_FILEID_OFFSET, (char *)&fsp->file_id, sizeof(fsp->file_id));
159 /* now we can receive more signals */
160 fd_pending = (sig_atomic_t)-1;
162 BlockSignals(False, RT_SIGNAL_LEASE);
167 /****************************************************************************
168 Attempt to set an kernel oplock on a file.
169 ****************************************************************************/
171 static BOOL linux_set_kernel_oplock(files_struct *fsp, int oplock_type)
173 if (linux_setlease(fsp->fd, F_WRLCK) == -1) {
174 DEBUG(3,("set_file_oplock: Refused oplock on file %s, fd = %d, dev = %x, \
175 inode = %.0f. (%s)\n",
176 fsp->fsp_name, fsp->fd,
177 (unsigned int)fsp->dev, (double)fsp->inode, strerror(errno)));
181 DEBUG(3,("set_file_oplock: got kernel oplock on file %s, dev = %x, inode = %.0f, file_id = %lu\n",
182 fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode, fsp->file_id));
187 /****************************************************************************
188 Release a kernel oplock on a file.
189 ****************************************************************************/
191 static void linux_release_kernel_oplock(files_struct *fsp)
195 * Check and print out the current kernel
196 * oplock state of this file.
198 int state = fcntl(fsp->fd, F_GETLEASE, 0);
199 dbgtext("release_kernel_oplock: file %s, dev = %x, inode = %.0f file_id = %lu has kernel \
200 oplock state of %x.\n", fsp->fsp_name, (unsigned int)fsp->dev,
201 (double)fsp->inode, fsp->file_id, state );
205 * Remove the kernel oplock on this file.
207 if (linux_setlease(fsp->fd, F_UNLCK) == -1) {
209 dbgtext("release_kernel_oplock: Error when removing kernel oplock on file " );
210 dbgtext("%s, dev = %x, inode = %.0f, file_id = %lu. Error was %s\n",
211 fsp->fsp_name, (unsigned int)fsp->dev,
212 (double)fsp->inode, fsp->file_id, strerror(errno) );
217 /****************************************************************************
218 Parse a kernel oplock message.
219 ****************************************************************************/
221 static BOOL linux_kernel_oplock_parse(char *msg_start, int msg_len, SMB_INO_T *inode,
222 SMB_DEV_T *dev, unsigned long *file_id)
224 /* Ensure that the msg length is correct. */
225 if (msg_len != KERNEL_OPLOCK_BREAK_MSG_LEN) {
226 DEBUG(0,("incorrect length for KERNEL_OPLOCK_BREAK_CMD (was %d, should be %d).\n",
227 msg_len, KERNEL_OPLOCK_BREAK_MSG_LEN));
231 memcpy((char *)inode, msg_start+KERNEL_OPLOCK_BREAK_INODE_OFFSET, sizeof(*inode));
232 memcpy((char *)dev, msg_start+KERNEL_OPLOCK_BREAK_DEV_OFFSET, sizeof(*dev));
233 memcpy((char *)file_id, msg_start+KERNEL_OPLOCK_BREAK_FILEID_OFFSET, sizeof(*file_id));
235 DEBUG(3,("kernel oplock break request for file dev = %x, inode = %.0f, file_id = %lu\n",
236 (unsigned int)*dev, (double)*inode, *file_id));
241 /****************************************************************************
242 See if a oplock message is waiting.
243 ****************************************************************************/
245 static BOOL linux_oplock_msg_waiting(fd_set *fds)
247 return signals_processed != signals_received;
250 /****************************************************************************
251 See if the kernel supports oplocks.
252 ****************************************************************************/
254 static BOOL linux_oplocks_available(void)
257 fd = open("/dev/null", O_RDONLY);
259 return False; /* uggh! */
260 ret = fcntl(fd, F_GETLEASE, 0);
262 return ret == F_UNLCK;
265 /****************************************************************************
266 Setup kernel oplocks.
267 ****************************************************************************/
269 struct kernel_oplocks *linux_init_kernel_oplocks(void)
271 static struct kernel_oplocks koplocks;
272 struct sigaction act;
274 if (!linux_oplocks_available()) {
275 DEBUG(3,("Linux kernel oplocks not available\n"));
279 act.sa_handler = NULL;
280 act.sa_sigaction = signal_handler;
281 act.sa_flags = SA_SIGINFO;
282 if (sigaction(RT_SIGNAL_LEASE, &act, NULL) != 0) {
283 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler\n"));
287 koplocks.receive_message = linux_oplock_receive_message;
288 koplocks.set_oplock = linux_set_kernel_oplock;
289 koplocks.release_oplock = linux_release_kernel_oplock;
290 koplocks.parse_message = linux_kernel_oplock_parse;
291 koplocks.msg_waiting = linux_oplock_msg_waiting;
292 koplocks.notification_fd = -1;
294 DEBUG(3,("Linux kernel oplocks enabled\n"));
299 void oplock_linux_dummy(void) {}
300 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */