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
22 #include "smbd/globals.h"
24 #if HAVE_KERNEL_OPLOCKS_LINUX
27 #define F_SETLEASE 1024
31 #define F_GETLEASE 1025
38 #ifndef RT_SIGNAL_LEASE
39 #define RT_SIGNAL_LEASE (SIGRTMIN+1)
46 /****************************************************************************
47 Handle a LEASE signal, incrementing the signals_received and blocking the signal.
48 ****************************************************************************/
50 static void signal_handler(int sig, siginfo_t *info, void *unused)
52 if (oplock_signals_received < FD_PENDING_SIZE - 1) {
53 fd_pending_array[oplock_signals_received] = (SIG_ATOMIC_T)info->si_fd;
54 oplock_signals_received++;
55 } /* Else signal is lost. */
56 sys_select_signal(RT_SIGNAL_LEASE);
60 * public function to get linux lease capability. Needed by some VFS modules (eg. gpfs.c)
62 void linux_set_lease_capability(void)
64 set_effective_capability(LEASE_CAPABILITY);
68 * Call to set the kernel lease signal handler
70 int linux_set_lease_sighandler(int fd)
72 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
73 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
80 /****************************************************************************
81 Call SETLEASE. If we get EACCES then we try setting up the right capability and
83 Use the SMB_VFS_LINUX_SETLEASE instead of this call directly.
84 ****************************************************************************/
86 int linux_setlease(int fd, int leasetype)
90 ret = fcntl(fd, F_SETLEASE, leasetype);
91 if (ret == -1 && errno == EACCES) {
92 set_effective_capability(LEASE_CAPABILITY);
93 ret = fcntl(fd, F_SETLEASE, leasetype);
99 /****************************************************************************
100 * Deal with the Linux kernel <--> smbd
101 * oplock break protocol.
102 ****************************************************************************/
104 static files_struct *linux_oplock_receive_message(struct kernel_oplocks *ctx)
109 BlockSignals(True, RT_SIGNAL_LEASE);
110 fd = fd_pending_array[0];
111 fsp = file_find_fd(fd);
112 fd_pending_array[0] = (SIG_ATOMIC_T)-1;
113 if (oplock_signals_received > 1)
114 memmove(CONST_DISCARD(void *, &fd_pending_array[0]),
115 CONST_DISCARD(void *, &fd_pending_array[1]),
116 sizeof(SIG_ATOMIC_T)*(oplock_signals_received-1));
117 oplock_signals_received--;
118 /* now we can receive more signals */
119 BlockSignals(False, RT_SIGNAL_LEASE);
124 /****************************************************************************
125 Attempt to set an kernel oplock on a file.
126 ****************************************************************************/
128 static bool linux_set_kernel_oplock(struct kernel_oplocks *ctx,
129 files_struct *fsp, int oplock_type)
131 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) {
132 DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, "
133 "fd = %d, file_id = %s. (%s)\n",
134 fsp->fsp_name, fsp->fh->fd,
135 file_id_string_tos(&fsp->file_id),
140 DEBUG(3,("linux_set_kernel_oplock: got kernel oplock on file %s, "
141 "file_id = %s gen_id = %lu\n",
142 fsp->fsp_name, file_id_string_tos(&fsp->file_id),
148 /****************************************************************************
149 Release a kernel oplock on a file.
150 ****************************************************************************/
152 static void linux_release_kernel_oplock(struct kernel_oplocks *ctx,
157 * Check and print out the current kernel
158 * oplock state of this file.
160 int state = fcntl(fsp->fh->fd, F_GETLEASE, 0);
161 dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
162 "gen_id = %lu has kernel oplock state "
163 "of %x.\n", fsp->fsp_name, file_id_string_tos(&fsp->file_id),
164 fsp->fh->gen_id, state );
168 * Remove the kernel oplock on this file.
170 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) {
172 dbgtext("linux_release_kernel_oplock: Error when "
173 "removing kernel oplock on file " );
174 dbgtext("%s, file_id = %s, gen_id = %lu. "
175 "Error was %s\n", fsp->fsp_name,
176 file_id_string_tos(&fsp->file_id),
177 fsp->fh->gen_id, strerror(errno) );
182 /****************************************************************************
183 See if a oplock message is waiting.
184 ****************************************************************************/
186 static bool linux_oplock_msg_waiting(struct kernel_oplocks *ctx)
188 return oplock_signals_received != 0;
191 /****************************************************************************
192 See if the kernel supports oplocks.
193 ****************************************************************************/
195 static bool linux_oplocks_available(void)
198 fd = open("/dev/null", O_RDONLY);
200 return False; /* uggh! */
201 ret = fcntl(fd, F_GETLEASE, 0);
203 return ret == F_UNLCK;
206 /****************************************************************************
207 Setup kernel oplocks.
208 ****************************************************************************/
210 static const struct kernel_oplocks_ops linux_koplocks = {
211 .receive_message = linux_oplock_receive_message,
212 .set_oplock = linux_set_kernel_oplock,
213 .release_oplock = linux_release_kernel_oplock,
214 .msg_waiting = linux_oplock_msg_waiting
217 struct kernel_oplocks *linux_init_kernel_oplocks(TALLOC_CTX *mem_ctx)
219 struct sigaction act;
220 struct kernel_oplocks *ctx;
222 if (!linux_oplocks_available()) {
223 DEBUG(3,("Linux kernel oplocks not available\n"));
227 ctx = talloc_zero(mem_ctx, struct kernel_oplocks);
229 DEBUG(0,("Linux Kernel oplocks talloc_Zero failed\n"));
233 ctx->ops = &linux_koplocks;
237 act.sa_handler = NULL;
238 act.sa_sigaction = signal_handler;
239 act.sa_flags = SA_SIGINFO;
240 sigemptyset( &act.sa_mask );
241 if (sigaction(RT_SIGNAL_LEASE, &act, NULL) != 0) {
242 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler\n"));
246 /* the signal can start off blocked due to a bug in bash */
247 BlockSignals(False, RT_SIGNAL_LEASE);
249 DEBUG(3,("Linux kernel oplocks enabled\n"));
254 void oplock_linux_dummy(void);
256 void oplock_linux_dummy(void) {}
257 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */