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https://github.com/samba-team/samba.git
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621f561a9c
Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Jeremy Allison <jra@samba.org>
244 lines
6.4 KiB
C
244 lines
6.4 KiB
C
/*
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Unix SMB/CIFS implementation.
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kernel oplock processing for Linux
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Copyright (C) Andrew Tridgell 2000
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#define DBGC_CLASS DBGC_LOCKING
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#include "includes.h"
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#include "system/filesys.h"
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#include "smbd/smbd.h"
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#include "smbd/globals.h"
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#ifdef HAVE_KERNEL_OPLOCKS_LINUX
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#ifndef RT_SIGNAL_LEASE
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#define RT_SIGNAL_LEASE (SIGRTMIN+1)
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#endif
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/*
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* Call to set the kernel lease signal handler
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*/
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int linux_set_lease_sighandler(int fd)
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{
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if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
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DEBUG(3,("Failed to set signal handler for kernel lease\n"));
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return -1;
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}
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return 0;
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}
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/****************************************************************************
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Call SETLEASE. If we get EACCES then we try setting up the right capability and
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try again.
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Use the SMB_VFS_LINUX_SETLEASE instead of this call directly.
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****************************************************************************/
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int linux_setlease(int fd, int leasetype)
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{
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int ret;
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int saved_errno = 0;
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/*
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* Ensure the lease owner is root to allow
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* correct delivery of lease-break signals.
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*/
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become_root();
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/* First set the signal handler. */
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if (linux_set_lease_sighandler(fd) == -1) {
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saved_errno = errno;
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ret = -1;
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goto out;
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}
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ret = fcntl(fd, F_SETLEASE, leasetype);
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if (ret == -1) {
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saved_errno = errno;
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}
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out:
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unbecome_root();
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if (ret == -1) {
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errno = saved_errno;
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}
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return ret;
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}
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/****************************************************************************
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* Deal with the Linux kernel <--> smbd
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* oplock break protocol.
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****************************************************************************/
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static void linux_oplock_signal_handler(struct tevent_context *ev_ctx,
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struct tevent_signal *se,
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int signum, int count,
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void *_info, void *private_data)
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{
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struct kernel_oplocks *ctx =
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talloc_get_type_abort(private_data,
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struct kernel_oplocks);
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struct smbd_server_connection *sconn =
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talloc_get_type_abort(ctx->private_data,
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struct smbd_server_connection);
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siginfo_t *info = (siginfo_t *)_info;
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int fd = info->si_fd;
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files_struct *fsp;
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fsp = file_find_fd(sconn, fd);
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if (fsp == NULL) {
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DEBUG(0,("linux_oplock_signal_handler: failed to find fsp for file fd=%d (file was closed ?)\n", fd ));
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return;
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}
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break_kernel_oplock(sconn->msg_ctx, fsp);
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}
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/****************************************************************************
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Attempt to set an kernel oplock on a file.
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****************************************************************************/
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static bool linux_set_kernel_oplock(struct kernel_oplocks *ctx,
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files_struct *fsp, int oplock_type)
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{
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struct file_id_buf idbuf;
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if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) {
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DBG_NOTICE("Refused oplock on file %s, "
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"fd = %d, file_id = %s. (%s)\n",
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fsp_str_dbg(fsp),
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fsp_get_io_fd(fsp),
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file_id_str_buf(fsp->file_id, &idbuf),
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strerror(errno));
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return False;
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}
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DBG_NOTICE("got kernel oplock on file %s, "
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"file_id = %s gen_id = %"PRIu64"\n",
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fsp_str_dbg(fsp),
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file_id_str_buf(fsp->file_id, &idbuf),
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fh_get_gen_id(fsp->fh));
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return True;
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}
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/****************************************************************************
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Release a kernel oplock on a file.
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****************************************************************************/
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static void linux_release_kernel_oplock(struct kernel_oplocks *ctx,
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files_struct *fsp, int oplock_type)
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{
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struct file_id_buf idbuf;
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if (DEBUGLVL(10)) {
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/*
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* Check and print out the current kernel
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* oplock state of this file.
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*/
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int state = fcntl(fsp_get_io_fd(fsp), F_GETLEASE, 0);
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dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
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"gen_id = %"PRIu64" has kernel oplock state "
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"of %x.\n",
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fsp_str_dbg(fsp),
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file_id_str_buf(fsp->file_id, &idbuf),
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fh_get_gen_id(fsp->fh),
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state);
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}
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/*
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* Remove the kernel oplock on this file.
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*/
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if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) {
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if (DEBUGLVL(0)) {
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dbgtext("linux_release_kernel_oplock: Error when "
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"removing kernel oplock on file " );
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dbgtext("%s, file_id = %s, gen_id = %"PRIu64". "
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"Error was %s\n",
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fsp_str_dbg(fsp),
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file_id_str_buf(fsp->file_id, &idbuf),
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fh_get_gen_id(fsp->fh),
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strerror(errno));
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}
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}
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}
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/****************************************************************************
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See if the kernel supports oplocks.
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****************************************************************************/
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static bool linux_oplocks_available(void)
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{
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int fd, ret;
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fd = open("/dev/null", O_RDONLY);
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if (fd == -1)
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return False; /* uggh! */
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ret = fcntl(fd, F_GETLEASE, 0);
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close(fd);
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return ret == F_UNLCK;
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}
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/****************************************************************************
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Setup kernel oplocks.
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****************************************************************************/
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static const struct kernel_oplocks_ops linux_koplocks = {
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.set_oplock = linux_set_kernel_oplock,
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.release_oplock = linux_release_kernel_oplock,
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};
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struct kernel_oplocks *linux_init_kernel_oplocks(struct smbd_server_connection *sconn)
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{
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struct kernel_oplocks *ctx;
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struct tevent_signal *se;
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if (!linux_oplocks_available()) {
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DEBUG(3,("Linux kernel oplocks not available\n"));
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return NULL;
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}
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ctx = talloc_zero(sconn, struct kernel_oplocks);
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if (!ctx) {
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DEBUG(0,("Linux Kernel oplocks talloc_Zero failed\n"));
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return NULL;
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}
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ctx->ops = &linux_koplocks;
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ctx->private_data = sconn;
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se = tevent_add_signal(sconn->ev_ctx,
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ctx,
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RT_SIGNAL_LEASE, SA_SIGINFO,
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linux_oplock_signal_handler,
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ctx);
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if (!se) {
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DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler"));
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TALLOC_FREE(ctx);
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return NULL;
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}
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DEBUG(3,("Linux kernel oplocks enabled\n"));
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return ctx;
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}
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#else
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void oplock_linux_dummy(void);
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void oplock_linux_dummy(void) {}
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#endif /* HAVE_KERNEL_OPLOCKS_LINUX */
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