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authorDavid Howells <dhowells@redhat.com>2020-03-13 16:46:08 +0300
committerDavid Howells <dhowells@redhat.com>2020-03-14 02:04:35 +0300
commitdde9f095583b3f375ba23979045ee10dfcebec2f (patch)
tree5cdbaa34aa49043a6f9e69db0d6d12e8cb877ad9 /fs/afs/cmservice.c
parent4636cf184d6d9a92a56c2554681ea520dd4fe49a (diff)
downloadlinux-dde9f095583b3f375ba23979045ee10dfcebec2f.tar.xz
afs: Fix handling of an abort from a service handler
When an AFS service handler function aborts a call, AF_RXRPC marks the call as complete - which means that it's not going to get any more packets from the receiver. This is a problem because reception of the final ACK is what triggers afs_deliver_to_call() to drop the final ref on the afs_call object. Instead, aborted AFS service calls may then just sit around waiting for ever or until they're displaced by a new call on the same connection channel or a connection-level abort. Fix this by calling afs_set_call_complete() to finalise the afs_call struct representing the call. However, we then need to drop the ref that stops the call from being deallocated. We can do this in afs_set_call_complete(), as the work queue is holding a separate ref of its own, but then we shouldn't do it in afs_process_async_call() and afs_delete_async_call(). call->drop_ref is set to indicate that a ref needs dropping for a call and this is dealt with when we transition a call to AFS_CALL_COMPLETE. But then we also need to get rid of the ref that pins an asynchronous client call. We can do this by the same mechanism, setting call->drop_ref for an async client call too. We can also get rid of call->incoming since nothing ever sets it and only one thing ever checks it (futilely). A trace of the rxrpc_call and afs_call struct ref counting looks like: <idle>-0 [001] ..s5 164.764892: rxrpc_call: c=00000002 SEE u=3 sp=rxrpc_new_incoming_call+0x473/0xb34 a=00000000442095b5 <idle>-0 [001] .Ns5 164.766001: rxrpc_call: c=00000002 QUE u=4 sp=rxrpc_propose_ACK+0xbe/0x551 a=00000000442095b5 <idle>-0 [001] .Ns4 164.766005: rxrpc_call: c=00000002 PUT u=3 sp=rxrpc_new_incoming_call+0xa3f/0xb34 a=00000000442095b5 <idle>-0 [001] .Ns7 164.766433: afs_call: c=00000002 WAKE u=2 o=11 sp=rxrpc_notify_socket+0x196/0x33c kworker/1:2-1810 [001] ...1 164.768409: rxrpc_call: c=00000002 SEE u=3 sp=rxrpc_process_call+0x25/0x7ae a=00000000442095b5 kworker/1:2-1810 [001] ...1 164.769439: rxrpc_tx_packet: c=00000002 e9f1a7a8:95786a88:00000008:09c5 00000001 00000000 02 22 ACK CallAck kworker/1:2-1810 [001] ...1 164.769459: rxrpc_call: c=00000002 PUT u=2 sp=rxrpc_process_call+0x74f/0x7ae a=00000000442095b5 kworker/1:2-1810 [001] ...1 164.770794: afs_call: c=00000002 QUEUE u=3 o=12 sp=afs_deliver_to_call+0x449/0x72c kworker/1:2-1810 [001] ...1 164.770829: afs_call: c=00000002 PUT u=2 o=12 sp=afs_process_async_call+0xdb/0x11e kworker/1:2-1810 [001] ...2 164.771084: rxrpc_abort: c=00000002 95786a88:00000008 s=0 a=1 e=1 K-1 kworker/1:2-1810 [001] ...1 164.771461: rxrpc_tx_packet: c=00000002 e9f1a7a8:95786a88:00000008:09c5 00000002 00000000 04 00 ABORT CallAbort kworker/1:2-1810 [001] ...1 164.771466: afs_call: c=00000002 PUT u=1 o=12 sp=SRXAFSCB_ProbeUuid+0xc1/0x106 The abort generated in SRXAFSCB_ProbeUuid(), labelled "K-1", indicates that the local filesystem/cache manager didn't recognise the UUID as its own. Fixes: 2067b2b3f484 ("afs: Fix the CB.ProbeUuid service handler to reply correctly") Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/afs/cmservice.c')
-rw-r--r--fs/afs/cmservice.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/afs/cmservice.c b/fs/afs/cmservice.c
index ff3994a6be23..6765949b3aab 100644
--- a/fs/afs/cmservice.c
+++ b/fs/afs/cmservice.c
@@ -244,6 +244,17 @@ static void afs_cm_destructor(struct afs_call *call)
}
/*
+ * Abort a service call from within an action function.
+ */
+static void afs_abort_service_call(struct afs_call *call, u32 abort_code, int error,
+ const char *why)
+{
+ rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
+ abort_code, error, why);
+ afs_set_call_complete(call, error, 0);
+}
+
+/*
* The server supplied a list of callbacks that it wanted to break.
*/
static void SRXAFSCB_CallBack(struct work_struct *work)
@@ -510,8 +521,7 @@ static void SRXAFSCB_ProbeUuid(struct work_struct *work)
if (memcmp(r, &call->net->uuid, sizeof(call->net->uuid)) == 0)
afs_send_empty_reply(call);
else
- rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
- 1, 1, "K-1");
+ afs_abort_service_call(call, 1, 1, "K-1");
afs_put_call(call);
_leave("");