kernel/linux.git/fs/afs/server.c, branch v6.19.11

afs: Fix potential null pointer dereference in afs_put_server

2025-09-25T07:18:17+00:00

afs_put_server() accessed server->debug_id before the NULL check, which could lead to a null pointer dereference. Move the debug_id assignment, ensuring we never dereference a NULL server pointer. Fixes: 2757a4dc1849 ("afs: Fix access after dec in put functions") Cc: stable@vger.kernel.org Signed-off-by: Zhen Ni Acked-by: David Howells Reviewed-by: Jeffrey Altman Signed-off-by: Christian Brauner

afs: Use rxgk RESPONSE to pass token for callback channel

2025-04-15T00:36:42+00:00

Implement in kafs the hook for adding appdata into a RESPONSE packet generated in response to an RxGK CHALLENGE packet, and include the key for securing the callback channel so that notifications from the fileserver get encrypted. This will be necessary when more complex notifications are used that convey changed data around. Signed-off-by: David Howells cc: Marc Dionne cc: Simon Horman cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20250411095303.2316168-13-dhowells@redhat.com Signed-off-by: Jakub Kicinski

treewide: Switch/rename to timer_delete[_sync]()

2025-04-05T08:30:12+00:00

timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree over and remove the historical wrapper inlines. Conversion was done with coccinelle plus manual fixups where necessary. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar

afs: Simplify cell record handling

2025-03-10T09:47:15+00:00

Simplify afs_cell record handling to avoid very occasional races that cause module removal to hang (it waits for all cell records to be removed). There are two things that particularly contribute to the difficulty: firstly, the code tries to pass a ref on the cell to the cell's maintenance work item (which gets awkward if the work item is already queued); and, secondly, there's an overall cell manager that tries to use just one timer for the entire cell collection (to avoid having loads of timers). However, both of these are probably unnecessarily restrictive. To simplify this, the following changes are made: (1) The cell record collection manager is removed. Each cell record manages itself individually. (2) Each afs_cell is given a second work item (cell->destroyer) that is queued when its refcount reaches zero. This is not done in the context of the putting thread as it might be in an inconvenient place to sleep. (3) Each afs_cell is given its own timer. The timer is used to expire the cell record after a period of unuse if not otherwise pinned and can also be used for other maintenance tasks if necessary (of which there are currently none as DNS refresh is triggered by filesystem operations). (4) The afs_cell manager work item (cell->manager) is no longer given a ref on the cell when queued; rather, the manager must be deleted. This does away with the need to deal with the consequences of losing a race to queue cell->manager. Clean up of extra queuing is deferred to the destroyer. (5) The cell destroyer work item makes sure the cell timer is removed and that the normal cell work is cancelled before farming the actual destruction off to RCU. (6) When a network namespace is destroyed or the kafs module is unloaded, it's now a simple matter of marking the namespace as dead then just waking up all the cell work items. They will then remove and destroy themselves once all remaining activity counts and/or a ref counts are dropped. This makes sure that all server records are dropped first. (7) The cell record state set is reduced to just four states: SETTING_UP, ACTIVE, REMOVING and DEAD. The record persists in the active state even when it's not being used until the time comes to remove it rather than downgrading it to an inactive state from whence it can be restored. This means that the cell still appears in /proc and /afs when not in use until it switches to the REMOVING state - at which point it is removed. Note that the REMOVING state is included so that someone wanting to resurrect the cell record is forced to wait whilst the cell is torn down in that state. Once it's in the DEAD state, it has been removed from net->cells tree and is no longer findable and can be replaced. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20250224234154.2014840-16-dhowells@redhat.com/ # v1 Link: https://lore.kernel.org/r/20250310094206.801057-12-dhowells@redhat.com/ # v4

afs: Fix afs_server ref accounting

2025-03-10T09:47:15+00:00

The current way that afs_server refs are accounted and cleaned up sometimes cause rmmod to hang when it is waiting for cell records to be removed. The problem is that the cell cleanup might occasionally happen before the server cleanup and then there's nothing that causes the cell to garbage-collect the remaining servers as they become inactive. Partially fix this by: (1) Give each afs_server record its own management timer that rather than relying on the cell manager's central timer to drive each individual cell's maintenance work item to garbage collect servers. This timer is set when afs_unuse_server() reduces a server's activity count to zero and will schedule the server's destroyer work item upon firing. (2) Give each afs_server record its own destroyer work item that removes the record from the cell's database, shuts down the timer, cancels any pending work for itself, sends an RPC to the server to cancel outstanding callbacks. This change, in combination with the timer, obviates the need to try and coordinate so closely between the cell record and a bunch of other server records to try and tear everything down in a coordinated fashion. With this, the cell record is pinned until the server RCU is complete and namespace/module removal will wait until all the cell records are removed. (3) Now that incoming calls are mapped to servers (and thus cells) using data attached to an rxrpc_peer, the UUID-to-server mapping tree is moved from the namespace to the cell (cell->fs_servers). This means there can no longer be duplicates therein - and that allows the mapping tree to be simpler as there doesn't need to be a chain of same-UUID servers that are in different cells. (4) The lock protecting the UUID mapping tree is switched to an rw_semaphore on the cell rather than a seqlock on the namespace as it's now only used during mounting in contexts in which we're allowed to sleep. (5) When it comes time for a cell that is being removed to purge its set of servers, it just needs to iterate over them and wake them up. Once a server becomes inactive, its destroyer work item will observe the state of the cell and immediately remove that record. (6) When a server record is removed, it is marked AFS_SERVER_FL_EXPIRED to prevent reattempts at removal. The record will be dispatched to RCU for destruction once its refcount reaches 0. (7) The AFS_SERVER_FL_UNCREATED/CREATING flags are used to synchronise simultaneous creation attempts. If one attempt fails, it will abandon the attempt and allow another to try again. Note that the record can't just be abandoned when dead as it's bound into a server list attached to a volume and only subject to replacement if the server list obtained for the volume from the VLDB changes. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20250224234154.2014840-15-dhowells@redhat.com/ # v1 Link: https://lore.kernel.org/r/20250310094206.801057-11-dhowells@redhat.com/ # v4

afs: Use the per-peer app data provided by rxrpc

2025-03-10T09:47:15+00:00

Make use of the per-peer application data that rxrpc now allows the application to store on the rxrpc_peer struct to hold a back pointer to the afs_server record that peer represents an endpoint for. Then, when a call comes in to the AFS cache manager, this can be used to map it to the correct server record rather than having to use a UUID-to-server mapping table and having to do an additional lookup. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20250224234154.2014840-14-dhowells@redhat.com/ # v1 Link: https://lore.kernel.org/r/20250310094206.801057-10-dhowells@redhat.com/ # v4

afs: Improve server refcount/active count tracing

2025-03-10T09:47:15+00:00

Improve server refcount/active count tracing to distinguish between simply getting/putting a ref and using/unusing the server record (which changes the activity count as well as the refcount). This makes it a bit easier to work out what's going on. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20250224234154.2014840-10-dhowells@redhat.com/ # v1 Link: https://lore.kernel.org/r/20250310094206.801057-6-dhowells@redhat.com/ # v4

afs: Give an afs_server object a ref on the afs_cell object it points to

2025-02-21T23:06:29+00:00

Give an afs_server object a ref on the afs_cell object it points to so that the cell doesn't get deleted before the server record. Whilst this is circular (cell -> vol -> server_list -> server -> cell), the ref only pins the memory, not the lifetime as that's controlled by the activity counter. When the volume's activity counter reaches 0, it detaches from the cell and discards its server list; when a cell's activity counter reaches 0, it discards its root volume. At that point, the circularity is cut. Fixes: d2ddc776a458 ("afs: Overhaul volume and server record caching and fileserver rotation") Signed-off-by: David Howells cc: Marc Dionne cc: Simon Horman cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20250218192250.296870-6-dhowells@redhat.com Signed-off-by: Jakub Kicinski

afs: Fix ignored callbacks over ipv4

2024-02-20T08:51:21+00:00

When searching for a matching peer, all addresses need to be searched, not just the ipv6 ones in the fs_addresses6 list. Given that the lists no longer contain addresses, there is little reason to splitting things between separate lists, so unify them into a single list. When processing an incoming callback from an ipv4 address, this would lead to a failure to set call->server, resulting in the callback being ignored and the client seeing stale contents. Fixes: 72904d7b9bfb ("rxrpc, afs: Allow afs to pin rxrpc_peer objects") Reported-by: Markus Suvanto Link: https://lists.infradead.org/pipermail/linux-afs/2024-February/008035.html Signed-off-by: Marc Dionne Signed-off-by: David Howells Link: https://lists.infradead.org/pipermail/linux-afs/2024-February/008037.html # v1 Link: https://lists.infradead.org/pipermail/linux-afs/2024-February/008066.html # v2 Link: https://lore.kernel.org/r/20240219143906.138346-2-dhowells@redhat.com Signed-off-by: Christian Brauner

afs: Apply server breaks to mmap'd files in the call processor

2024-01-01T16:37:27+00:00

Apply server breaks to mmap'd files that are being used from that server from the call processor work function rather than punting it off to a workqueue. The work item, afs_server_init_callback(), then bumps each individual inode off to its own work item introducing a potentially lengthy delay. This reduces that delay at the cost of extending the amount of time we delay replying to the CB.InitCallBack3 notification RPC from the server. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org