/*
* Try to claim a lock that was previously blocked.
*
* Note that we use both the RPC_GRANTED_MSG call _and_ an async
* RPC thread when notifying the client. This seems like overkill...
* Here's why:
* - we don't want to use a synchronous RPC thread, otherwise
* we might find ourselves hanging on a dead portmapper.
* - Some lockd implementations (e.g. HP) don't react to
* RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
*/
static void
nlmsvc_grant_blocked(struct nlm_block *block)
{
struct nlm_file *file = block->b_file;
struct nlm_lock *lock = &block->b_call.a_args.lock;
struct file_lock *conflock;
int error;
dprintk("lockd: grant blocked lock %p\n", block);
/* First thing is lock the file */
down(&file->f_sema);
/* Unlink block request from list */
nlmsvc_remove_block(block);
/* If b_granted is true this means we've been here before.
* Just retry the grant callback, possibly refreshing the RPC
* binding */
if (block->b_granted) {
nlm_rebind_host(block->b_host);
goto callback;
}
/* Try the lock operation again */
if ((conflock = posix_test_lock(&file->f_file, &lock->fl)) != NULL) {
/* Bummer, we blocked again */
dprintk("lockd: lock still blocked\n");
nlmsvc_insert_block(block, NLM_NEVER);
posix_block_lock(conflock, &lock->fl);
up(&file->f_sema);
return;
}
/* Alright, no conflicting lock. Now lock it for real. If the
* following yields an error, this is most probably due to low
* memory. Retry the lock in a few seconds.
*/
if ((error = posix_lock_file(&file->f_file, &lock->fl, 0)) < 0) {
printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
-error, __FUNCTION__);
nlmsvc_insert_block(block, jiffies + 10 * HZ);
up(&file->f_sema);
return;
}
callback:
/* Lock was granted by VFS. */
dprintk("lockd: GRANTing blocked lock.\n");
block->b_granted = 1;
block->b_incall = 1;
/* Schedule next grant callback in 30 seconds */
nlmsvc_insert_block(block, jiffies + 30 * HZ);
/* Call the client */
nlmclnt_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
nlmsvc_grant_callback);
up(&file->f_sema);
}
/*
* We received a GRANT_RES callback. Try to find the corresponding
* block.
*/
void
nlmsvc_grant_reply(u32 cookie, u32 status)
{
struct nlm_block *block;
struct nlm_file *file;
if (!(block = nlmsvc_find_block(cookie)))
return;
file = block->b_file;
file->f_count++;
down(&file->f_sema);
if ((block = nlmsvc_find_block(cookie)) != NULL) {
if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
/* Try again in a couple of seconds */
nlmsvc_insert_block(block, jiffies + 10 * HZ);
block = NULL;
} else {
/* Lock is now held by client, or has been rejected.
* In both cases, the block should be removed. */
file->f_count++;
up(&file->f_sema);
if (status == NLM_LCK_GRANTED)
nlmsvc_delete_block(block, 0);
else
nlmsvc_delete_block(block, 1);
}
}
if (!block)
up(&file->f_sema);
nlm_release_file(file);
}
/*
* This is the callback from the RPC layer when the NLM_GRANTED_MSG
* RPC call has succeeded or timed out.
* Like all RPC callbacks, it is invoked by the rpciod process, so it
* better not sleep. Therefore, we put the blocked lock on the nlm_blocked
* chain once more in order to have it removed by lockd itself (which can
* then sleep on the file semaphore without disrupting e.g. the nfs client).
*/
static void
nlmsvc_grant_callback(struct rpc_task *task)
{
struct nlm_rqst *call = (struct nlm_rqst *) task->tk_calldata;
struct nlm_block *block;
unsigned long timeout;
dprintk("lockd: GRANT_MSG RPC callback\n");
if (!(block = nlmsvc_find_block(call->a_args.cookie))) {
dprintk("lockd: no block for cookie %x\n", call->a_args.cookie);
return;
}
/* Technically, we should down the file semaphore here. Since we
* move the block towards the head of the queue only, no harm
* can be done, though. */
if (task->tk_status < 0) {
/* RPC error: Re-insert for retransmission */
timeout = jiffies + 10 * HZ;
} else if (block->b_done) {
/* Block already removed, kill it for real */
timeout = 0;
} else {
/* Call was successful, now wait for client callback */
timeout = jiffies + 60 * HZ;
}
nlmsvc_insert_block(block, timeout);
svc_wake_up(block->b_daemon);
block->b_incall = 0;
nlm_release_host(call->a_host);
rpc_release_task(task);
}
/*
* We received a GRANT_RES callback. Try to find the corresponding
* block.
*/
void
nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
{
struct nlm_block *block;
struct nlm_file *file;
dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
*(unsigned int *)(cookie->data),
ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
return;
file = block->b_file;
file->f_count++;
down(&file->f_sema);
if ((block = nlmsvc_find_block(cookie,&rqstp->rq_addr)) != NULL) {
if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
/* Try again in a couple of seconds */
nlmsvc_insert_block(block, 10 * HZ);
block = NULL;
} else {
/* Lock is now held by client, or has been rejected.
* In both cases, the block should be removed. */
file->f_count++;
up(&file->f_sema);
if (status == NLM_LCK_GRANTED)
nlmsvc_delete_block(block, 0);
else
nlmsvc_delete_block(block, 1);
}
}
if (!block)
up(&file->f_sema);
nlm_release_file(file);
}
/*
* Delete a block. If the lock was cancelled or the grant callback
* failed, unlock is set to 1.
* It is the caller's responsibility to check whether the file
* can be closed hereafter.
*/
static void
nlmsvc_delete_block(struct nlm_block *block, int unlock)
{
struct file_lock *fl = &block->b_call.a_args.lock.fl;
struct nlm_file *file = block->b_file;
struct nlm_block **bp;
dprintk("lockd: deleting block %p...\n", block);
/* Remove block from list */
nlmsvc_remove_block(block);
posix_unblock_lock(&file->f_file, fl);
block->b_granted = 0;
/* If the block is in the middle of a GRANT callback,
* don't kill it yet. */
if (block->b_incall) {
nlmsvc_insert_block(block, NLM_NEVER);
block->b_done = 1;
return;
}
/* Remove block from file's list of blocks */
for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
if (*bp == block) {
*bp = block->b_fnext;
break;
}
}
if (block->b_host)
nlm_release_host(block->b_host);
nlmclnt_freegrantargs(&block->b_call);
kfree(block);
}
/*
* Unblock a blocked lock request. This is a callback invoked from the
* VFS layer when a lock on which we blocked is removed.
*
* This function doesn't grant the blocked lock instantly, but rather moves
* the block to the head of nlm_blocked where it can be picked up by lockd.
*/
static void
nlmsvc_notify_blocked(struct file_lock *fl)
{
struct nlm_block **bp, *block;
dprintk("lockd: VFS unblock notification for block %p\n", fl);
for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
nlmsvc_insert_block(block, 0);
svc_wake_up(block->b_daemon);
return;
}
}
printk(KERN_WARNING "lockd: notification for unknown block!\n");
}
/*
* This is the callback from the RPC layer when the NLM_GRANTED_MSG
* RPC call has succeeded or timed out.
* Like all RPC callbacks, it is invoked by the rpciod process, so it
* better not sleep. Therefore, we put the blocked lock on the nlm_blocked
* chain once more in order to have it removed by lockd itself (which can
* then sleep on the file semaphore without disrupting e.g. the nfs client).
*/
static void
nlmsvc_grant_callback(struct rpc_task *task)
{
struct nlm_rqst *call = (struct nlm_rqst *) task->tk_calldata;
struct nlm_block *block;
unsigned long timeout;
struct sockaddr_in *peer_addr = RPC_PEERADDR(task->tk_client);
dprintk("lockd: GRANT_MSG RPC callback\n");
dprintk("callback: looking for cookie %x, host (%08x)\n",
*(unsigned int *)(call->a_args.cookie.data),
ntohl(peer_addr->sin_addr.s_addr));
if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
dprintk("lockd: no block for cookie %x, host (%08x)\n",
*(u32 *)(call->a_args.cookie.data),
ntohl(peer_addr->sin_addr.s_addr));
return;
}
/* Technically, we should down the file semaphore here. Since we
* move the block towards the head of the queue only, no harm
* can be done, though. */
if (task->tk_status < 0) {
/* RPC error: Re-insert for retransmission */
timeout = 10 * HZ;
} else if (block->b_done) {
/* Block already removed, kill it for real */
timeout = 0;
} else {
/* Call was successful, now wait for client callback */
timeout = 60 * HZ;
}
nlmsvc_insert_block(block, timeout);
svc_wake_up(block->b_daemon);
block->b_incall = 0;
nlm_release_host(call->a_host);
}
/*
* Attempt to establish a lock, and if it can't be granted, block it
* if required.
*/
u32
nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
struct nlm_lock *lock, int wait, u32 cookie)
{
struct file_lock *conflock;
struct nlm_block *block;
int error;
dprintk("lockd: nlmsvc_lock(%04x/%ld, ty=%d, pi=%d, %ld-%ld, bl=%d)\n",
file->f_file.f_dentry->d_inode->i_dev,
file->f_file.f_dentry->d_inode->i_ino,
lock->fl.fl_type, lock->fl.fl_pid,
lock->fl.fl_start,
lock->fl.fl_end,
wait);
/* Lock file against concurrent access */
down(&file->f_sema);
/* Get existing block (in case client is busy-waiting) */
block = nlmsvc_lookup_block(file, lock, 0);
lock->fl.fl_flags |= FL_LOCKD;
again:
if (!(conflock = posix_test_lock(&file->f_file, &lock->fl))) {
error = posix_lock_file(&file->f_file, &lock->fl, 0);
if (block)
nlmsvc_delete_block(block, 0);
up(&file->f_sema);
dprintk("lockd: posix_lock_file returned %d\n", -error);
switch(-error) {
case 0:
return nlm_granted;
case EDEADLK: /* no applicable NLM status */
case EAGAIN:
return nlm_lck_denied;
default: /* includes ENOLCK */
return nlm_lck_denied_nolocks;
}
}
if (!wait) {
up(&file->f_sema);
return nlm_lck_denied;
}
/* If we don't have a block, create and initialize it. Then
* retry because we may have slept in kmalloc. */
if (block == NULL) {
dprintk("lockd: blocking on this lock (allocating).\n");
if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie)))
return nlm_lck_denied_nolocks;
goto again;
}
/* Append to list of blocked */
nlmsvc_insert_block(block, NLM_NEVER);
/* Now add block to block list of the conflicting lock */
dprintk("lockd: blocking on this lock.\n");
posix_block_lock(conflock, &block->b_call.a_args.lock.fl);
up(&file->f_sema);
return nlm_lck_blocked;
}
/*
* Attempt to establish a lock, and if it can't be granted, block it
* if required.
*/
u32
nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
{
struct file_lock *conflock;
struct nlm_block *block, *nblock = NULL;
int error;
dprintk("lockd: nlmsvc_lock(%04x/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
file->f_file.f_dentry->d_inode->i_dev,
file->f_file.f_dentry->d_inode->i_ino,
lock->fl.fl_type, lock->fl.fl_pid,
(long long)lock->fl.fl_start,
(long long)lock->fl.fl_end,
wait);
/* Get existing block (in case client is busy-waiting) */
block = nlmsvc_lookup_block(file, lock, 0);
lock->fl.fl_flags |= FL_LOCKD;
again:
/* Lock file against concurrent access */
down(&file->f_sema);
if (!(conflock = posix_test_lock(&file->f_file, &lock->fl))) {
error = posix_lock_file(&file->f_file, &lock->fl, 0);
if (block)
nlmsvc_delete_block(block, 0);
up(&file->f_sema);
dprintk("lockd: posix_lock_file returned %d\n", -error);
switch(-error) {
case 0:
return nlm_granted;
case EDEADLK:
return nlm_deadlock;
case EAGAIN:
return nlm_lck_denied;
default: /* includes ENOLCK */
return nlm_lck_denied_nolocks;
}
}
if (!wait) {
up(&file->f_sema);
return nlm_lck_denied;
}
if (posix_locks_deadlock(&lock->fl, conflock)) {
if (nblock)
nlmsvc_delete_block(nblock, 0);
up(&file->f_sema);
return nlm_deadlock;
}
/* If we don't have a block, create and initialize it. Then
* retry because we may have slept in kmalloc. */
/* We have to release f_sema as nlmsvc_create_block may try to
* to claim it while doing host garbage collection */
if (block == NULL) {
up(&file->f_sema);
dprintk("lockd: blocking on this lock (allocating).\n");
if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie)))
return nlm_lck_denied_nolocks;
nblock = block;
goto again;
}
/* Append to list of blocked */
nlmsvc_insert_block(block, NLM_NEVER);
if (list_empty(&block->b_call.a_args.lock.fl.fl_block)) {
/* Now add block to block list of the conflicting lock
if we haven't done so. */
dprintk("lockd: blocking on this lock.\n");
posix_block_lock(conflock, &block->b_call.a_args.lock.fl);
}
up(&file->f_sema);
return nlm_lck_blocked;
}
