lockd: Add refcounting to struct nlm_block
Otherwise, the block may disappear from underneath us when in
nlmsvc_retry_blocked.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 1d3a74d..20caece 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -39,6 +39,7 @@
#define nlm_deadlock nlm_lck_denied
#endif
+static void nlmsvc_release_block(struct nlm_block *block);
static void nlmsvc_insert_block(struct nlm_block *block, unsigned long);
static int nlmsvc_remove_block(struct nlm_block *block);
@@ -58,6 +59,7 @@
struct nlm_block **bp, *b;
dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
+ kref_get(&block->b_count);
if (block->b_queued)
nlmsvc_remove_block(block);
bp = &nlm_blocked;
@@ -90,6 +92,7 @@
if (b == block) {
*bp = block->b_next;
block->b_queued = 0;
+ nlmsvc_release_block(block);
return 1;
}
}
@@ -123,6 +126,7 @@
*head = block->b_next;
block->b_queued = 0;
}
+ kref_get(&block->b_count);
return block;
}
}
@@ -155,6 +159,8 @@
break;
}
+ if (block != NULL)
+ kref_get(&block->b_count);
return block;
}
@@ -188,6 +194,7 @@
memset(block, 0, sizeof(*block));
locks_init_lock(&block->b_call.a_args.lock.fl);
locks_init_lock(&block->b_call.a_res.lock.fl);
+ kref_init(&block->b_count);
if (!nlmclnt_setgrantargs(&block->b_call, lock))
goto failed_free;
@@ -228,27 +235,24 @@
* It is the caller's responsibility to check whether the file
* can be closed hereafter.
*/
-static int
-nlmsvc_delete_block(struct nlm_block *block)
+static int nlmsvc_unlink_block(struct nlm_block *block)
{
- struct file_lock *fl = &block->b_call.a_args.lock.fl;
- struct nlm_file *file = block->b_file;
- struct nlm_block **bp;
int status;
-
- dprintk("lockd: deleting block %p...\n", block);
+ dprintk("lockd: unlinking block %p...\n", block);
/* Remove block from list */
+ status = posix_unblock_lock(block->b_file->f_file, &block->b_call.a_args.lock.fl);
nlmsvc_remove_block(block);
- status = posix_unblock_lock(file->f_file, fl);
+ return status;
+}
- /* 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 status;
- }
+static void nlmsvc_free_block(struct kref *kref)
+{
+ struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
+ struct nlm_file *file = block->b_file;
+ struct nlm_block **bp;
+
+ dprintk("lockd: freeing block %p...\n", block);
/* Remove block from file's list of blocks */
for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
@@ -262,7 +266,12 @@
nlm_release_host(block->b_host);
nlmclnt_freegrantargs(&block->b_call);
kfree(block);
- return status;
+}
+
+static void nlmsvc_release_block(struct nlm_block *block)
+{
+ if (block != NULL)
+ kref_put(&block->b_count, nlmsvc_free_block);
}
/*
@@ -282,7 +291,7 @@
block->b_host->h_inuse = 1;
else if (action == NLM_ACT_UNLOCK) {
if (host == NULL || host == block->b_host)
- nlmsvc_delete_block(block);
+ nlmsvc_unlink_block(block);
}
}
up(&file->f_sema);
@@ -318,9 +327,9 @@
block = nlmsvc_lookup_block(file, lock, 0);
if (block == NULL) {
if (newblock != NULL)
- lock = &newblock->b_call.a_args.lock.fl;
+ lock = &newblock->b_call.a_args.lock;
} else
- lock = &block->b_call.a_args.lock.fl;
+ lock = &block->b_call.a_args.lock;
error = posix_lock_file(file->f_file, &lock->fl);
lock->fl.fl_flags &= ~FL_SLEEP;
@@ -363,12 +372,10 @@
/* Append to list of blocked */
nlmsvc_insert_block(newblock, NLM_NEVER);
- newblock = NULL;
-
out:
up(&file->f_sema);
- if (newblock != NULL)
- nlmsvc_delete_block(newblock);
+ nlmsvc_release_block(newblock);
+ nlmsvc_release_block(block);
dprintk("lockd: nlmsvc_lock returned %u\n", ret);
return ret;
}
@@ -450,8 +457,10 @@
(long long)lock->fl.fl_end);
down(&file->f_sema);
- if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
- status = nlmsvc_delete_block(block);
+ if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) {
+ status = nlmsvc_unlink_block(block);
+ nlmsvc_release_block(block);
+ }
up(&file->f_sema);
return status ? nlm_lck_denied : nlm_granted;
}
@@ -514,7 +523,7 @@
down(&file->f_sema);
/* Unlink block request from list */
- nlmsvc_remove_block(block);
+ nlmsvc_unlink_block(block);
/* If b_granted is true this means we've been here before.
* Just retry the grant callback, possibly refreshing the RPC
@@ -525,7 +534,6 @@
}
/* Try the lock operation again */
- posix_unblock_lock(file->f_file, &lock->fl);
lock->fl.fl_flags |= FL_SLEEP;
error = posix_lock_file(file->f_file, &lock->fl);
lock->fl.fl_flags &= ~FL_SLEEP;
@@ -548,16 +556,15 @@
/* 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, 30 * HZ);
/* Call the client */
- nlm_get_host(block->b_call.a_host);
+ kref_get(&block->b_count);
if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
&nlmsvc_grant_ops) < 0)
- nlm_release_host(block->b_call.a_host);
+ nlmsvc_release_block(block);
out_unlock:
up(&file->f_sema);
}
@@ -573,20 +580,10 @@
static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
{
struct nlm_rqst *call = data;
- struct nlm_block *block;
+ struct nlm_block *block = container_of(call, struct nlm_block, b_call);
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 %s, host (%u.%u.%u.%u)\n",
- nlmdbg_cookie2a(&call->a_args.cookie),
- NIPQUAD(peer_addr->sin_addr.s_addr));
- if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
- dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
- nlmdbg_cookie2a(&call->a_args.cookie),
- NIPQUAD(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
@@ -603,9 +600,7 @@
}
nlmsvc_insert_block(block, timeout);
svc_wake_up(block->b_daemon);
- block->b_incall = 0;
-
- nlm_release_host(call->a_host);
+ nlmsvc_release_block(block);
}
static const struct rpc_call_ops nlmsvc_grant_ops = {
@@ -631,20 +626,19 @@
file->f_count++;
down(&file->f_sema);
- block = nlmsvc_find_block(cookie, &rqstp->rq_addr);
if (block) {
if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
/* Try again in a couple of seconds */
nlmsvc_insert_block(block, 10 * HZ);
- up(&file->f_sema);
} else {
/* Lock is now held by client, or has been rejected.
* In both cases, the block should be removed. */
- nlmsvc_delete_block(block);
- up(&file->f_sema);
+ nlmsvc_unlink_block(block);
}
}
+ up(&file->f_sema);
nlm_release_file(file);
+ nlmsvc_release_block(block);
}
/*
@@ -667,10 +661,12 @@
break;
dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
block, block->b_when, block->b_done);
+ kref_get(&block->b_count);
if (block->b_done)
- nlmsvc_delete_block(block);
+ nlmsvc_unlink_block(block);
else
nlmsvc_grant_blocked(block);
+ nlmsvc_release_block(block);
}
if ((block = nlm_blocked) && block->b_when != NLM_NEVER)