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 "system/filesys.h"
23 #include "smbd/smbd.h"
24 #include "smbd/globals.h"
26 #ifdef HAVE_KERNEL_OPLOCKS_LINUX
29 #define F_SETLEASE 1024
33 #define F_GETLEASE 1025
40 #ifndef RT_SIGNAL_LEASE
41 #define RT_SIGNAL_LEASE (SIGRTMIN+1)
49 * public function to get linux lease capability. Needed by some VFS modules (eg. gpfs.c)
51 void linux_set_lease_capability(void)
53 set_effective_capability(LEASE_CAPABILITY);
57 * Call to set the kernel lease signal handler
59 int linux_set_lease_sighandler(int fd)
61 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
62 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
69 /****************************************************************************
70 Call SETLEASE. If we get EACCES then we try setting up the right capability and
72 Use the SMB_VFS_LINUX_SETLEASE instead of this call directly.
73 ****************************************************************************/
75 int linux_setlease(int fd, int leasetype)
81 * Ensure the lease owner is root to allow
82 * correct delivery of lease-break signals.
87 /* First set the signal handler. */
88 if (linux_set_lease_sighandler(fd) == -1) {
93 ret = fcntl(fd, F_SETLEASE, leasetype);
108 /****************************************************************************
109 * Deal with the Linux kernel <--> smbd
110 * oplock break protocol.
111 ****************************************************************************/
113 static 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)
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;
129 * This function doesn't expect any specific impersonation, as it only
130 * sends messages to other smbd processes. And messaging_send_iov_from()
131 * already handles EACCES.
134 fsp = file_find_fd(sconn, fd);
136 DEBUG(0,("linux_oplock_signal_handler: failed to find fsp for file fd=%d (file was closed ?)\n", fd ));
139 break_kernel_oplock(sconn->msg_ctx, fsp);
142 /****************************************************************************
143 Attempt to set an kernel oplock on a file.
144 ****************************************************************************/
146 static bool linux_set_kernel_oplock(struct kernel_oplocks *ctx,
147 files_struct *fsp, int oplock_type)
149 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) {
150 DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, "
151 "fd = %d, file_id = %s. (%s)\n",
152 fsp_str_dbg(fsp), fsp->fh->fd,
153 file_id_string_tos(&fsp->file_id),
158 DEBUG(3,("linux_set_kernel_oplock: got kernel oplock on file %s, "
159 "file_id = %s gen_id = %lu\n",
160 fsp_str_dbg(fsp), file_id_string_tos(&fsp->file_id),
166 /****************************************************************************
167 Release a kernel oplock on a file.
168 ****************************************************************************/
170 static void linux_release_kernel_oplock(struct kernel_oplocks *ctx,
171 files_struct *fsp, int oplock_type)
175 * Check and print out the current kernel
176 * oplock state of this file.
178 int state = fcntl(fsp->fh->fd, F_GETLEASE, 0);
179 dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
180 "gen_id = %lu has kernel oplock state "
181 "of %x.\n", fsp_str_dbg(fsp),
182 file_id_string_tos(&fsp->file_id),
183 fsp->fh->gen_id, state );
187 * Remove the kernel oplock on this file.
189 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) {
191 dbgtext("linux_release_kernel_oplock: Error when "
192 "removing kernel oplock on file " );
193 dbgtext("%s, file_id = %s, gen_id = %lu. "
194 "Error was %s\n", fsp_str_dbg(fsp),
195 file_id_string_tos(&fsp->file_id),
196 fsp->fh->gen_id, strerror(errno) );
201 /****************************************************************************
202 See if the kernel supports oplocks.
203 ****************************************************************************/
205 static bool linux_oplocks_available(void)
208 fd = open("/dev/null", O_RDONLY);
210 return False; /* uggh! */
211 ret = fcntl(fd, F_GETLEASE, 0);
213 return ret == F_UNLCK;
216 /****************************************************************************
217 Setup kernel oplocks.
218 ****************************************************************************/
220 static const struct kernel_oplocks_ops linux_koplocks = {
221 .set_oplock = linux_set_kernel_oplock,
222 .release_oplock = linux_release_kernel_oplock,
225 struct kernel_oplocks *linux_init_kernel_oplocks(struct smbd_server_connection *sconn)
227 struct kernel_oplocks *ctx;
228 struct tevent_signal *se;
230 if (!linux_oplocks_available()) {
231 DEBUG(3,("Linux kernel oplocks not available\n"));
235 ctx = talloc_zero(sconn, struct kernel_oplocks);
237 DEBUG(0,("Linux Kernel oplocks talloc_Zero failed\n"));
241 ctx->ops = &linux_koplocks;
242 ctx->private_data = sconn;
245 * linux_oplock_signal_handler() only
246 * sends messages to other smbd processes
247 * and doesn't require any impersonation.
248 * So we can just use the raw tevent_context.
250 se = tevent_add_signal(sconn->raw_ev_ctx,
252 RT_SIGNAL_LEASE, SA_SIGINFO,
253 linux_oplock_signal_handler,
256 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler"));
261 DEBUG(3,("Linux kernel oplocks enabled\n"));
266 void oplock_linux_dummy(void);
268 void oplock_linux_dummy(void) {}
269 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */