kernel.git/fs/afs/cmservice.c, branch linux-4.16.y

afs: Fix the handling of CB.InitCallBackState3 to find the server by UUID

2018-06-20T19:01:44Z

[ Upstream commit 001ab5a67ee5d191c64aebf4b4ef8c7a0dcfd2bc ] Fix the handling of the CB.InitCallBackState3 service call to find the record of a server that we're using by looking it up by the UUID passed as the parameter rather than by its address (of which it might have many, and which may change). Fixes: c35eccb1f614 ("[AFS]: Implement the CB.InitCallBackState3 operation.") Signed-off-by: David Howells Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

afs: Protect call->state changes against signals

2017-11-13T15:38:21Z

Protect call->state changes against the call being prematurely terminated due to a signal. What can happen is that a signal causes afs_wait_for_call_to_complete() to abort an afs_call because it's not yet complete whilst afs_deliver_to_call() is delivering data to that call. If the data delivery causes the state to change, this may overwrite the state of the afs_call, making it not-yet-complete again - but no further notifications will be forthcoming from AF_RXRPC as the rxrpc call has been aborted and completed, so kAFS will just hang in various places waiting for that call or on page bits that need clearing by that call. A tracepoint to monitor call state changes is also provided. Signed-off-by: David Howells

afs: Overhaul the callback handling

2017-11-13T15:38:18Z

Overhaul the AFS callback handling by the following means: (1) Don't give up callback promises on vnodes that we are no longer using, rather let them just expire on the server or let the server break them. This is actually more efficient for the server as the callback lookup is expensive if there are lots of extant callbacks. (2) Only give up the callback promises we have from a server when the server record is destroyed. Then we can just give up *all* the callback promises on it in one go. (3) Servers can end up being shared between cells if cells are aliased, so don't add all the vnodes being backed by a particular server into a big FID-indexed tree on that server as there may be duplicates. Instead have each volume instance (~= superblock) register an interest in a server as it starts to make use of it and use this to allow the processor for callbacks from the server to find the superblock and thence the inode corresponding to the FID being broken by means of ilookup_nowait(). (4) Rather than iterating over the entire callback list when a mass-break comes in from the server, maintain a counter of mass-breaks in afs_server (cb_seq) and make afs_validate() check it against the copy in afs_vnode. It would be nice not to have to take a read_lock whilst doing this, but that's tricky without using RCU. (5) Save a ref on the fileserver we're using for a call in the afs_call struct so that we can access its cb_s_break during call decoding. (6) Write-lock around callback and status storage in a vnode and read-lock around getattr so that we don't see the status mid-update. This has the following consequences: (1) Data invalidation isn't seen until someone calls afs_validate() on a vnode. Unfortunately, we need to use a key to query the server, but getting one from a background thread is tricky without caching loads of keys all over the place. (2) Mass invalidation isn't seen until someone calls afs_validate(). (3) Callback breaking is going to hit the inode_hash_lock quite a bit. Could this be replaced with rcu_read_lock() since inodes are destroyed under RCU conditions. Signed-off-by: David Howells

afs: Rename struct afs_call server member to cm_server

2017-11-13T15:38:18Z

Rename the server member of struct afs_call to cm_server as we're only going to be using it for incoming calls for the Cache Manager service. This makes it easier to differentiate from the pointer to the target server for the client, which will point to a different structure to allow for callback handling. Signed-off-by: David Howells

afs: Connect up the CB.ProbeUuid

2017-11-13T15:38:18Z

The handler for the CB.ProbeUuid operation in the cache manager is implemented, but isn't listed in the switch-statement of operation selection, so won't be used. Fix this by adding it. Signed-off-by: David Howells

afs: Consolidate abort_to_error translators

2017-11-13T15:38:17Z

The AFS abort code space is shared across all services, so there's no need for separate abort_to_error translators for each service. Consolidate them into a single function and remove the function pointers for them. Signed-off-by: David Howells

afs: Push the net ns pointer to more places

2017-11-13T15:38:17Z

Push the network namespace pointer to more places in AFS, including the afs_server structure (which doesn't hold a ref on the netns). In particular, afs_put_cell() now takes requires a net ns parameter so that it can safely alter the netns after decrementing the cell usage count - the cell will be deallocated by a background thread after being cached for a period, which means that it's not safe to access it after reducing its usage count. Signed-off-by: David Howells

afs: Lay the groundwork for supporting network namespaces

2017-11-13T15:38:16Z

Lay the groundwork for supporting network namespaces (netns) to the AFS filesystem by moving various global features to a network-namespace struct (afs_net) and providing an instance of this as a temporary global variable that everything uses via accessor functions for the moment. The following changes have been made: (1) Store the netns in the superblock info. This will be obtained from the mounter's nsproxy on a manual mount and inherited from the parent superblock on an automount. (2) The cell list is made per-netns. It can be viewed through /proc/net/afs/cells and also be modified by writing commands to that file. (3) The local workstation cell is set per-ns in /proc/net/afs/rootcell. This is unset by default. (4) The 'rootcell' module parameter, which sets a cell and VL server list modifies the init net namespace, thereby allowing an AFS root fs to be theoretically used. (5) The volume location lists and the file lock manager are made per-netns. (6) The AF_RXRPC socket and associated I/O bits are made per-ns. The various workqueues remain global for the moment. Changes still to be made: (1) /proc/fs/afs/ should be moved to /proc/net/afs/ and a symlink emplaced from the old name. (2) A per-netns subsys needs to be registered for AFS into which it can store its per-netns data. (3) Rather than the AF_RXRPC socket being opened on module init, it needs to be opened on the creation of a superblock in that netns. (4) The socket needs to be closed when the last superblock using it is destroyed and all outstanding client calls on it have been completed. This prevents a reference loop on the namespace. (5) It is possible that several namespaces will want to use AFS, in which case each one will need its own UDP port. These can either be set through /proc/net/afs/cm_port or the kernel can pick one at random. The init_ns gets 7001 by default. Other issues that need resolving: (1) The DNS keyring needs net-namespacing. (2) Where do upcalls go (eg. DNS request-key upcall)? (3) Need something like open_socket_in_file_ns() syscall so that AFS command line tools attempting to operate on an AFS file/volume have their RPC calls go to the right place. Signed-off-by: David Howells

uuid,afs: move struct uuid_v1 back into afs

2017-06-05T14:56:34Z

This essentially is a partial revert of commit ff548773 ("afs: Move UUID struct to linux/uuid.h") and moves struct uuid_v1 back into fs/afs as struct afs_uuid. It however keeps it as big endian structure so that we can use the normal uuid generation helpers when casting to/from struct afs_uuid. The V1 uuid intrepretation in struct form isn't really useful to the rest of the kernel, and not really compatible to it either, so move it back to AFS instead of polluting the global uuid.h. Signed-off-by: Christoph Hellwig Acked-by: David Howells

afs: Deal with an empty callback array

2017-03-16T16:27:44Z

Servers may send a callback array that is the same size as the FID array, or an empty array. If the callback count is 0, the code would attempt to read (fid_count * 12) bytes of data, which would fail and result in an unmarshalling error. This would lead to stale data for remotely modified files or directories. Store the callback array size in the internal afs_call structure and use that to determine the amount of data to read. Signed-off-by: Marc Dionne