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samba-mirror/source3/smbd/oplock.c

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/*
Unix SMB/CIFS implementation.
oplock processing
Copyright (C) Andrew Tridgell 1992-1998
Copyright (C) Jeremy Allison 1998 - 2001
Copyright (C) Volker Lendecke 2005
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
/* Current number of oplocks we have outstanding. */
static int32 exclusive_oplocks_open = 0;
static int32 level_II_oplocks_open = 0;
BOOL global_client_failed_oplock_break = False;
extern struct timeval smb_last_time;
extern uint32 global_client_caps;
extern int smb_read_error;
static struct kernel_oplocks *koplocks;
/****************************************************************************
Get the number of current exclusive oplocks.
****************************************************************************/
int32 get_number_of_exclusive_open_oplocks(void)
{
return exclusive_oplocks_open;
}
/****************************************************************************
Return True if an oplock message is pending.
****************************************************************************/
BOOL oplock_message_waiting(fd_set *fds)
{
if (koplocks && koplocks->msg_waiting(fds))
return True;
return False;
}
/****************************************************************************
Read an oplock break message from either the oplock UDP fd or the
kernel (if kernel oplocks are supported).
If timeout is zero then *fds contains the file descriptors that
are ready to be read and acted upon. If timeout is non-zero then
*fds contains the file descriptors to be selected on for read.
The timeout is in milliseconds
****************************************************************************/
void process_kernel_oplocks(void)
{
fd_set fds;
FD_ZERO(&fds);
smb_read_error = 0;
/*
* We need to check for kernel oplocks before going into the select
* here, as the EINTR generated by the linux kernel oplock may have
* already been eaten. JRA.
*/
if (!koplocks) {
return;
}
while (koplocks->msg_waiting(&fds)) {
files_struct *fsp;
struct kernel_oplock_message msg;
fsp = koplocks->receive_message(&fds);
if (fsp == NULL) {
DEBUG(3, ("Kernel oplock message announced, but none "
"received\n"));
return;
}
msg.dev = fsp->dev;
msg.inode = fsp->inode;
msg.file_id = fsp->file_id;
message_send_pid(pid_to_procid(sys_getpid()),
MSG_SMB_KERNEL_BREAK,
&msg, sizeof(msg), True);
}
}
/****************************************************************************
Attempt to set an oplock on a file. Always succeeds if kernel oplocks are
disabled (just sets flags). Returns True if oplock set.
****************************************************************************/
BOOL set_file_oplock(files_struct *fsp, int oplock_type)
{
if (koplocks && !koplocks->set_oplock(fsp, oplock_type))
return False;
fsp->oplock_type = oplock_type;
fsp->sent_oplock_break = NO_BREAK_SENT;
if (oplock_type == LEVEL_II_OPLOCK)
level_II_oplocks_open++;
else
exclusive_oplocks_open++;
DEBUG(5,("set_file_oplock: granted oplock on file %s, dev = %x, inode = %.0f, file_id = %lu, \
tv_sec = %x, tv_usec = %x\n",
fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode, fsp->file_id,
(int)fsp->open_time.tv_sec, (int)fsp->open_time.tv_usec ));
return True;
}
/****************************************************************************
Attempt to release an oplock on a file. Decrements oplock count.
****************************************************************************/
void release_file_oplock(files_struct *fsp)
{
if ((fsp->oplock_type != NO_OPLOCK) &&
(fsp->oplock_type != FAKE_LEVEL_II_OPLOCK) &&
koplocks) {
koplocks->release_oplock(fsp);
}
if (fsp->oplock_type == LEVEL_II_OPLOCK)
level_II_oplocks_open--;
else if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type))
exclusive_oplocks_open--;
SMB_ASSERT(exclusive_oplocks_open>=0);
SMB_ASSERT(level_II_oplocks_open>=0);
fsp->oplock_type = NO_OPLOCK;
fsp->sent_oplock_break = NO_BREAK_SENT;
flush_write_cache(fsp, OPLOCK_RELEASE_FLUSH);
}
/****************************************************************************
Attempt to downgrade an oplock on a file. Doesn't decrement oplock count.
****************************************************************************/
static void downgrade_file_oplock(files_struct *fsp)
{
if (koplocks)
koplocks->release_oplock(fsp);
fsp->oplock_type = LEVEL_II_OPLOCK;
exclusive_oplocks_open--;
level_II_oplocks_open++;
fsp->sent_oplock_break = NO_BREAK_SENT;
}
/****************************************************************************
Remove a file oplock. Copes with level II and exclusive.
Locks then unlocks the share mode lock. Client can decide to go directly
to none even if a "break-to-level II" was sent.
****************************************************************************/
BOOL remove_oplock(files_struct *fsp)
{
SMB_DEV_T dev = fsp->dev;
SMB_INO_T inode = fsp->inode;
BOOL ret;
struct share_mode_lock *lck;
/* Remove the oplock flag from the sharemode. */
lck = get_share_mode_lock(NULL, fsp->dev, fsp->inode, NULL, NULL);
if (lck == NULL) {
DEBUG(0,("remove_oplock: failed to lock share entry for "
"file %s\n", fsp->fsp_name ));
return False;
}
ret = remove_share_oplock(lck, fsp);
if (!ret) {
DEBUG(0,("remove_oplock: failed to remove share oplock for "
"file %s fnum %d, dev = %x, inode = %.0f\n",
fsp->fsp_name, fsp->fnum, (unsigned int)dev,
(double)inode));
}
release_file_oplock(fsp);
talloc_free(lck);
return ret;
}
/*
* Deal with a reply when a break-to-level II was sent.
*/
BOOL downgrade_oplock(files_struct *fsp)
{
SMB_DEV_T dev = fsp->dev;
SMB_INO_T inode = fsp->inode;
BOOL ret;
struct share_mode_lock *lck;
lck = get_share_mode_lock(NULL, fsp->dev, fsp->inode, NULL, NULL);
if (lck == NULL) {
DEBUG(0,("downgrade_oplock: failed to lock share entry for "
"file %s\n", fsp->fsp_name ));
return False;
}
ret = downgrade_share_oplock(lck, fsp);
if (!ret) {
DEBUG(0,("downgrade_oplock: failed to downgrade share oplock "
"for file %s fnum %d, dev = %x, inode = %.0f\n",
fsp->fsp_name, fsp->fnum, (unsigned int)dev,
(double)inode));
}
downgrade_file_oplock(fsp);
talloc_free(lck);
return ret;
}
/****************************************************************************
Setup the listening set of file descriptors for an oplock break
message either from the UDP socket or from the kernel. Returns the maximum
fd used.
****************************************************************************/
int setup_oplock_select_set( fd_set *fds)
{
int maxfd = 0;
if (koplocks && koplocks->notification_fd != -1) {
FD_SET(koplocks->notification_fd, fds);
maxfd = MAX(maxfd, koplocks->notification_fd);
}
return maxfd;
}
/****************************************************************************
Set up an oplock break message.
****************************************************************************/
static char *new_break_smb_message(TALLOC_CTX *mem_ctx,
files_struct *fsp, uint8 cmd)
{
char *result = TALLOC_ARRAY(mem_ctx, char, smb_size + 8*2 + 0);
if (result == NULL) {
DEBUG(0, ("talloc failed\n"));
return NULL;
}
memset(result,'\0',smb_size);
set_message(result,8,0,True);
SCVAL(result,smb_com,SMBlockingX);
SSVAL(result,smb_tid,fsp->conn->cnum);
SSVAL(result,smb_pid,0xFFFF);
SSVAL(result,smb_uid,0);
SSVAL(result,smb_mid,0xFFFF);
SCVAL(result,smb_vwv0,0xFF);
SSVAL(result,smb_vwv2,fsp->fnum);
SCVAL(result,smb_vwv3,LOCKING_ANDX_OPLOCK_RELEASE);
SCVAL(result,smb_vwv3+1,cmd);
return result;
}
/****************************************************************************
Function to do the waiting before sending a local break.
****************************************************************************/
static void wait_before_sending_break(void)
{
struct timeval cur_tv;
long wait_left = (long)lp_oplock_break_wait_time();
if (wait_left == 0)
return;
GetTimeOfDay(&cur_tv);
wait_left -= ((cur_tv.tv_sec - smb_last_time.tv_sec)*1000) +
((cur_tv.tv_usec - smb_last_time.tv_usec)/1000);
if(wait_left > 0) {
wait_left = MIN(wait_left, 1000);
sys_usleep(wait_left * 1000);
}
}
/****************************************************************************
Ensure that we have a valid oplock.
****************************************************************************/
static files_struct *initial_break_processing(SMB_DEV_T dev, SMB_INO_T inode, unsigned long file_id)
{
files_struct *fsp = NULL;
if( DEBUGLVL( 3 ) ) {
dbgtext( "initial_break_processing: called for dev = %x, inode = %.0f file_id = %lu\n",
(unsigned int)dev, (double)inode, file_id);
dbgtext( "Current oplocks_open (exclusive = %d, levelII = %d)\n",
exclusive_oplocks_open, level_II_oplocks_open );
}
/*
* We need to search the file open table for the
* entry containing this dev and inode, and ensure
* we have an oplock on it.
*/
fsp = file_find_dif(dev, inode, file_id);
if(fsp == NULL) {
/* The file could have been closed in the meantime - return success. */
if( DEBUGLVL( 3 ) ) {
dbgtext( "initial_break_processing: cannot find open file with " );
dbgtext( "dev = %x, inode = %.0f file_id = %lu", (unsigned int)dev,
(double)inode, file_id);
dbgtext( "allowing break to succeed.\n" );
}
return NULL;
}
/* Ensure we have an oplock on the file */
/*
* There is a potential race condition in that an oplock could
* have been broken due to another udp request, and yet there are
* still oplock break messages being sent in the udp message
* queue for this file. So return true if we don't have an oplock,
* as we may have just freed it.
*/
if(fsp->oplock_type == NO_OPLOCK) {
if( DEBUGLVL( 3 ) ) {
dbgtext( "initial_break_processing: file %s ", fsp->fsp_name );
dbgtext( "(dev = %x, inode = %.0f, file_id = %lu) has no oplock.\n",
(unsigned int)dev, (double)inode, fsp->file_id );
dbgtext( "Allowing break to succeed regardless.\n" );
}
return NULL;
}
return fsp;
}
static void oplock_timeout_handler(struct timed_event *te,
const struct timeval *now,
void *private_data)
{
files_struct *fsp = private_data;
DEBUG(0, ("Oplock break failed -- replying anyway\n"));
global_client_failed_oplock_break = True;
remove_oplock(fsp);
reply_to_oplock_break_requests(fsp);
}
static void process_oplock_break_message(int msg_type, struct process_id src,
void *buf, size_t len)
{
struct share_mode_entry *msg = buf;
files_struct *fsp;
char *break_msg;
BOOL break_to_level2 = False;
BOOL sign_state;
if (buf == NULL) {
DEBUG(0, ("Got NULL buffer\n"));
return;
}
if (len != sizeof(*msg)) {
DEBUG(0, ("Got invalid msg len %d\n", (int)len));
return;
}
DEBUG(10, ("Got oplock break message from pid %d: %d/%d/%d\n",
(int)procid_to_pid(&src), (int)msg->dev, (int)msg->inode,
(int)msg->share_file_id));
fsp = initial_break_processing(msg->dev, msg->inode,
msg->share_file_id);
if (fsp == NULL) {
/* We hit race here. Break messages are sent, and before we
* get to process this message, we have closed the file. Reply
* with 'ok, oplock broken' */
DEBUG(3, ("Did not find fsp\n"));
become_root();
message_send_pid(src, MSG_SMB_BREAK_RESPONSE,
msg, sizeof(*msg), True);
unbecome_root();
return;
}
if (fsp->sent_oplock_break != NO_BREAK_SENT) {
/* Remember we have to inform the requesting PID when the
* client replies */
msg->pid = src;
ADD_TO_ARRAY(NULL, struct share_mode_entry, *msg,
&fsp->pending_break_messages,
&fsp->num_pending_break_messages);
return;
}
if (EXCLUSIVE_OPLOCK_TYPE(msg->op_type) &&
!EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type)) {
DEBUG(3, ("Already downgraded oplock on %.0f/%.0f: %s\n",
(double)fsp->dev, (double)fsp->inode,
fsp->fsp_name));
become_root();
message_send_pid(src, MSG_SMB_BREAK_RESPONSE,
msg, sizeof(*msg), True);
unbecome_root();
return;
}
if ((msg_type == MSG_SMB_BREAK_REQUEST) &&
(global_client_caps & CAP_LEVEL_II_OPLOCKS) &&
!koplocks && /* NOTE: we force levelII off for kernel oplocks -
* this will change when it is supported */
lp_level2_oplocks(SNUM(fsp->conn))) {
break_to_level2 = True;
}
break_msg = new_break_smb_message(NULL, fsp, break_to_level2 ?
OPLOCKLEVEL_II : OPLOCKLEVEL_NONE);
if (break_msg == NULL) {
exit_server("Could not talloc break_msg\n");
}
/* Need to wait before sending a break message to a file of our own */
if (procid_to_pid(&src) == sys_getpid()) {
wait_before_sending_break();
}
/* Save the server smb signing state. */
sign_state = srv_oplock_set_signing(False);
show_msg(break_msg);
if (!send_smb(smbd_server_fd(), break_msg)) {
exit_server("oplock_break: send_smb failed.");
}
/* Restore the sign state to what it was. */
srv_oplock_set_signing(sign_state);
talloc_free(break_msg);
if (msg_type == MSG_SMB_BREAK_REQUEST) {
fsp->sent_oplock_break = break_to_level2 ?
LEVEL_II_BREAK_SENT:BREAK_TO_NONE_SENT;
} else {
/* Async level2 request, don't send a reply */
fsp->sent_oplock_break = ASYNC_LEVEL_II_BREAK_SENT;
}
msg->pid = src;
ADD_TO_ARRAY(NULL, struct share_mode_entry, *msg,
&fsp->pending_break_messages,
&fsp->num_pending_break_messages);
if (fsp->oplock_timeout != NULL) {
DEBUG(0, ("Logic problem -- have an oplock event hanging "
"around\n"));
}
fsp->oplock_timeout =
add_timed_event(NULL,
timeval_current_ofs(OPLOCK_BREAK_TIMEOUT, 0),
"oplock_timeout_handler",
oplock_timeout_handler, fsp);
if (fsp->oplock_timeout == NULL) {
DEBUG(0, ("Could not add oplock timeout handler\n"));
}
}
static void process_kernel_oplock_break(int msg_type, struct process_id src,
void *buf, size_t len)
{
struct kernel_oplock_message *msg = buf;
files_struct *fsp;
char *break_msg;
BOOL sign_state;
if (buf == NULL) {
DEBUG(0, ("Got NULL buffer\n"));
return;
}
if (len != sizeof(*msg)) {
DEBUG(0, ("Got invalid msg len %d\n", (int)len));
return;
}
DEBUG(10, ("Got kernel oplock break message from pid %d: %d/%d/%d\n",
(int)procid_to_pid(&src), (int)msg->dev, (int)msg->inode,
(int)msg->file_id));
fsp = initial_break_processing(msg->dev, msg->inode, msg->file_id);
if (fsp == NULL) {
DEBUG(3, ("Got a kernel oplock break message for a file "
"I don't know about\n"));
return;
}
if (fsp->sent_oplock_break != NO_BREAK_SENT) {
/* This is ok, kernel oplocks come in completely async */
DEBUG(3, ("Got a kernel oplock request while waiting for a "
"break reply\n"));
return;
}
break_msg = new_break_smb_message(NULL, fsp, OPLOCKLEVEL_NONE);
if (break_msg == NULL) {
exit_server("Could not talloc break_msg\n");
}
/* Save the server smb signing state. */
sign_state = srv_oplock_set_signing(False);
show_msg(break_msg);
if (!send_smb(smbd_server_fd(), break_msg)) {
exit_server("oplock_break: send_smb failed.");
}
/* Restore the sign state to what it was. */
srv_oplock_set_signing(sign_state);
talloc_free(break_msg);
fsp->sent_oplock_break = BREAK_TO_NONE_SENT;
}
void reply_to_oplock_break_requests(files_struct *fsp)
{
int i;
become_root();
for (i=0; i<fsp->num_pending_break_messages; i++) {
struct share_mode_entry *msg = &fsp->pending_break_messages[i];
message_send_pid(msg->pid, MSG_SMB_BREAK_RESPONSE,
msg, sizeof(*msg), True);
}
unbecome_root();
SAFE_FREE(fsp->pending_break_messages);
fsp->num_pending_break_messages = 0;
if (fsp->oplock_timeout != NULL) {
talloc_free(fsp->oplock_timeout);
fsp->oplock_timeout = NULL;
}
return;
}
static void process_oplock_break_response(int msg_type, struct process_id src,
void *buf, size_t len)
{
struct share_mode_entry *msg = buf;
if (buf == NULL) {
DEBUG(0, ("Got NULL buffer\n"));
return;
}
if (len != sizeof(*msg)) {
DEBUG(0, ("Got invalid msg len %d\n", (int)len));
return;
}
DEBUG(10, ("Got oplock break response from pid %d: %d/%d/%d mid %d\n",
(int)procid_to_pid(&src), (int)msg->dev, (int)msg->inode,
(int)msg->share_file_id, (int)msg->op_mid));
/* Here's the hack from open.c, store the mid in the 'port' field */
schedule_deferred_open_smb_message(msg->op_mid);
}
static void process_open_retry_message(int msg_type, struct process_id src,
void *buf, size_t len)
{
struct share_mode_entry *msg = buf;
if (buf == NULL) {
DEBUG(0, ("Got NULL buffer\n"));
return;
}
if (len != sizeof(*msg)) {
DEBUG(0, ("Got invalid msg len %d\n", (int)len));
return;
}
DEBUG(10, ("Got open retry msg from pid %d: %d/%d mid %d\n",
(int)procid_to_pid(&src), (int)msg->dev, (int)msg->inode,
(int)msg->op_mid));
schedule_deferred_open_smb_message(msg->op_mid);
}
/****************************************************************************
This function is called on any file modification or lock request. If a file
is level 2 oplocked then it must tell all other level 2 holders to break to
none.
****************************************************************************/
void release_level_2_oplocks_on_change(files_struct *fsp)
{
int i;
struct share_mode_lock *lck;
/*
* If this file is level II oplocked then we need
* to grab the shared memory lock and inform all
* other files with a level II lock that they need
* to flush their read caches. We keep the lock over
* the shared memory area whilst doing this.
*/
if (!LEVEL_II_OPLOCK_TYPE(fsp->oplock_type))
return;
lck = get_share_mode_lock(NULL, fsp->dev, fsp->inode, NULL, NULL);
if (lck == NULL) {
DEBUG(0,("release_level_2_oplocks_on_change: failed to lock "
"share mode entry for file %s.\n", fsp->fsp_name ));
}
DEBUG(10,("release_level_2_oplocks_on_change: num_share_modes = %d\n",
lck->num_share_modes ));
if (fsp->oplock_type == FAKE_LEVEL_II_OPLOCK) {
/* See if someone else has already downgraded us, then we
don't have to do anything */
for (i=0; i<lck->num_share_modes; i++) {
struct share_mode_entry *e = &lck->share_modes[i];
if ((e->op_type == NO_OPLOCK) &&
(e->share_file_id == fsp->file_id) &&
(e->dev == fsp->dev) &&
(e->inode == fsp->inode) &&
(procid_is_me(&e->pid))) {
/* We're done */
fsp->oplock_type = NO_OPLOCK;
talloc_free(lck);
return;
}
}
}
for(i = 0; i < lck->num_share_modes; i++) {
struct share_mode_entry *share_entry = &lck->share_modes[i];
/*
* As there could have been multiple writes waiting at the
* lock_share_entry gate we may not be the first to
* enter. Hence the state of the op_types in the share mode
* entries may be partly NO_OPLOCK and partly LEVEL_II
* oplock. It will do no harm to re-send break messages to
* those smbd's that are still waiting their turn to remove
* their LEVEL_II state, and also no harm to ignore existing
* NO_OPLOCK states. JRA.
*/
DEBUG(10,("release_level_2_oplocks_on_change: "
"share_entry[%i]->op_type == %d\n",
i, share_entry->op_type ));
if ((share_entry->op_type == NO_OPLOCK) ||
(share_entry->op_type == FAKE_LEVEL_II_OPLOCK)) {
continue;
}
/* Paranoia .... */
if (EXCLUSIVE_OPLOCK_TYPE(share_entry->op_type)) {
DEBUG(0,("release_level_2_oplocks_on_change: PANIC. "
"share mode entry %d is an exlusive "
"oplock !\n", i ));
talloc_free(lck);
abort();
}
become_root();
message_send_pid(share_entry->pid, MSG_SMB_ASYNC_LEVEL2_BREAK,
share_entry, sizeof(*share_entry), True);
unbecome_root();
}
remove_all_share_oplocks(lck, fsp);
talloc_free(lck);
}
/****************************************************************************
Setup oplocks for this process.
****************************************************************************/
BOOL init_oplocks(void)
{
DEBUG(3,("open_oplock_ipc: opening loopback UDP socket.\n"));
message_register(MSG_SMB_BREAK_REQUEST,
process_oplock_break_message);
message_register(MSG_SMB_ASYNC_LEVEL2_BREAK,
process_oplock_break_message);
message_register(MSG_SMB_BREAK_RESPONSE,
process_oplock_break_response);
message_register(MSG_SMB_KERNEL_BREAK,
process_kernel_oplock_break);
message_register(MSG_SMB_OPEN_RETRY,
process_open_retry_message);
if (lp_kernel_oplocks()) {
#if HAVE_KERNEL_OPLOCKS_IRIX
koplocks = irix_init_kernel_oplocks();
#elif HAVE_KERNEL_OPLOCKS_LINUX
koplocks = linux_init_kernel_oplocks();
#endif
}
return True;
}