VERSION: Bump version up to 3.6.20.
[Samba.git] / source3 / smbd / oplock_linux.c
blob82523f2dce53357806927aa13795f0889d89bd6c
1 /*
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
21 #include "includes.h"
22 #include "system/filesys.h"
23 #include "smbd/smbd.h"
24 #include "smbd/globals.h"
26 #if HAVE_KERNEL_OPLOCKS_LINUX
28 #ifndef F_SETLEASE
29 #define F_SETLEASE 1024
30 #endif
32 #ifndef F_GETLEASE
33 #define F_GETLEASE 1025
34 #endif
36 #ifndef CAP_LEASE
37 #define CAP_LEASE 28
38 #endif
40 #ifndef RT_SIGNAL_LEASE
41 #define RT_SIGNAL_LEASE (SIGRTMIN+1)
42 #endif
44 #ifndef F_SETSIG
45 #define F_SETSIG 10
46 #endif
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);
56 /*
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"));
63 return -1;
66 return 0;
69 /****************************************************************************
70 Call SETLEASE. If we get EACCES then we try setting up the right capability and
71 try again.
72 Use the SMB_VFS_LINUX_SETLEASE instead of this call directly.
73 ****************************************************************************/
75 int linux_setlease(int fd, int leasetype)
77 int ret;
78 int saved_errno;
81 * Ensure the lease owner is root to allow
82 * correct delivery of lease-break signals.
85 become_root();
87 /* First set the signal handler. */
88 if (linux_set_lease_sighandler(fd) == -1) {
89 saved_errno = errno;
90 ret = -1;
91 goto out;
93 ret = fcntl(fd, F_SETLEASE, leasetype);
94 if (ret == -1) {
95 saved_errno = errno;
98 out:
100 unbecome_root();
102 if (ret == -1) {
103 errno = saved_errno;
105 return ret;
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 siginfo_t *info = (siginfo_t *)_info;
119 int fd = info->si_fd;
120 files_struct *fsp;
122 fsp = file_find_fd(smbd_server_conn, fd);
123 if (fsp == NULL) {
124 DEBUG(0,("linux_oplock_signal_handler: failed to find fsp for file fd=%d (file was closed ?)\n", fd ));
125 return;
127 break_kernel_oplock(fsp->conn->sconn->msg_ctx, fsp);
130 /****************************************************************************
131 Attempt to set an kernel oplock on a file.
132 ****************************************************************************/
134 static bool linux_set_kernel_oplock(struct kernel_oplocks *ctx,
135 files_struct *fsp, int oplock_type)
137 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) {
138 DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, "
139 "fd = %d, file_id = %s. (%s)\n",
140 fsp_str_dbg(fsp), fsp->fh->fd,
141 file_id_string_tos(&fsp->file_id),
142 strerror(errno)));
143 return False;
146 DEBUG(3,("linux_set_kernel_oplock: got kernel oplock on file %s, "
147 "file_id = %s gen_id = %lu\n",
148 fsp_str_dbg(fsp), file_id_string_tos(&fsp->file_id),
149 fsp->fh->gen_id));
151 return True;
154 /****************************************************************************
155 Release a kernel oplock on a file.
156 ****************************************************************************/
158 static void linux_release_kernel_oplock(struct kernel_oplocks *ctx,
159 files_struct *fsp, int oplock_type)
161 if (DEBUGLVL(10)) {
163 * Check and print out the current kernel
164 * oplock state of this file.
166 int state = fcntl(fsp->fh->fd, F_GETLEASE, 0);
167 dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
168 "gen_id = %lu has kernel oplock state "
169 "of %x.\n", fsp_str_dbg(fsp),
170 file_id_string_tos(&fsp->file_id),
171 fsp->fh->gen_id, state );
175 * Remove the kernel oplock on this file.
177 if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) {
178 if (DEBUGLVL(0)) {
179 dbgtext("linux_release_kernel_oplock: Error when "
180 "removing kernel oplock on file " );
181 dbgtext("%s, file_id = %s, gen_id = %lu. "
182 "Error was %s\n", fsp_str_dbg(fsp),
183 file_id_string_tos(&fsp->file_id),
184 fsp->fh->gen_id, strerror(errno) );
189 /****************************************************************************
190 See if the kernel supports oplocks.
191 ****************************************************************************/
193 static bool linux_oplocks_available(void)
195 int fd, ret;
196 fd = open("/dev/null", O_RDONLY);
197 if (fd == -1)
198 return False; /* uggh! */
199 ret = fcntl(fd, F_GETLEASE, 0);
200 close(fd);
201 return ret == F_UNLCK;
204 /****************************************************************************
205 Setup kernel oplocks.
206 ****************************************************************************/
208 static const struct kernel_oplocks_ops linux_koplocks = {
209 .set_oplock = linux_set_kernel_oplock,
210 .release_oplock = linux_release_kernel_oplock,
211 .contend_level2_oplocks_begin = NULL,
212 .contend_level2_oplocks_end = NULL,
215 struct kernel_oplocks *linux_init_kernel_oplocks(TALLOC_CTX *mem_ctx)
217 struct kernel_oplocks *ctx;
218 struct tevent_signal *se;
220 if (!linux_oplocks_available()) {
221 DEBUG(3,("Linux kernel oplocks not available\n"));
222 return NULL;
225 ctx = talloc_zero(mem_ctx, struct kernel_oplocks);
226 if (!ctx) {
227 DEBUG(0,("Linux Kernel oplocks talloc_Zero failed\n"));
228 return NULL;
231 ctx->ops = &linux_koplocks;
233 se = tevent_add_signal(smbd_event_context(),
234 ctx,
235 RT_SIGNAL_LEASE, SA_SIGINFO,
236 linux_oplock_signal_handler,
237 ctx);
238 if (!se) {
239 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler"));
240 TALLOC_FREE(ctx);
241 return NULL;
244 ctx->private_data = se;
246 DEBUG(3,("Linux kernel oplocks enabled\n"));
248 return ctx;
250 #else
251 void oplock_linux_dummy(void);
253 void oplock_linux_dummy(void) {}
254 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */