kernel/linux.git/fs/afs/server_list.c, branch v6.6.141

afs: Fix the server_list to unuse a displaced server rather than putting it

2025-03-07T15:45:38+00:00

[ Upstream commit add117e48df4788a86a21bd0515833c0a6db1ad1 ] When allocating and building an afs_server_list struct object from a VLDB record, we look up each server address to get the server record for it - but a server may have more than one entry in the record and we discard the duplicate pointers. Currently, however, when we discard, we only put a server record, not unuse it - but the lookup got as an active-user count. The active-user count on an afs_server_list object determines its lifetime whereas the refcount keeps the memory backing it around. Failing to reduce the active-user counter prevents the record from being cleaned up and can lead to multiple copied being seen - and pointing to deleted afs_cell objects and other such things. Fix this by switching the incorrect 'put' to an 'unuse' instead. Without this, occasionally, a dead server record can be seen in /proc/net/afs/servers and list corruption may be observed: list_del corruption. prev->next should be ffff888102423e40, but was 0000000000000000. (prev=ffff88810140cd38) Fixes: 977e5f8ed0ab ("afs: Split the usage count on struct afs_server") Signed-off-by: David Howells cc: Marc Dionne cc: Simon Horman cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20250218192250.296870-5-dhowells@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

afs: Make it possible to find the volumes that are using a server

2025-03-07T15:45:38+00:00

[ Upstream commit ca0e79a46097d54e4af46c67c852479d97af35bb ] Make it possible to find the afs_volume structs that are using an afs_server struct to aid in breaking volume callbacks. The way this is done is that each afs_volume already has an array of afs_server_entry records that point to the servers where that volume might be found. An afs_volume backpointer and a list node is added to each entry and each entry is then added to an RCU-traversable list on the afs_server to which it points. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Stable-dep-of: add117e48df4 ("afs: Fix the server_list to unuse a displaced server rather than putting it") Signed-off-by: Sasha Levin

afs: Fix afs_server_list to be cleaned up with RCU

2023-12-03T06:33:02+00:00

[ Upstream commit e6bace7313d61e31f2b16fa3d774fd8cb3cb869e ] afs_server_list is accessed with the rcu_read_lock() held from volume->servers, so it needs to be cleaned up correctly. Fix this by using kfree_rcu() instead of kfree(). Fixes: 8a070a964877 ("afs: Detect cell aliases 1 - Cells with root volumes") Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: Sasha Levin

afs: Reorganise volume and server trees to be rooted on the cell

2020-06-04T14:37:57+00:00

Reorganise afs_volume objects such that they're in a tree keyed on volume ID, rooted at on an afs_cell object rather than being in multiple trees, each of which is rooted on an afs_server object. afs_server structs become per-cell and acquire a pointer to the cell. The process of breaking a callback then starts with finding the server by its network address, following that to the cell and then looking up each volume ID in the volume tree. This is simpler than the afs_vol_interest/afs_cb_interest N:M mapping web and allows those structs and the code for maintaining them to be simplified or removed. It does make a couple of things a bit more tricky, though: (1) Operations now start with a volume, not a server, so there can be more than one answer as to whether or not the server we'll end up using supports the FS.InlineBulkStatus RPC. (2) CB RPC operations that specify the server UUID. There's still a tree of servers by UUID on the afs_net struct, but the UUIDs in it aren't guaranteed unique. Signed-off-by: David Howells

afs: Retain more of the VLDB record for alias detection

2020-06-04T14:37:57+00:00

Save more bits from the volume location database record obtained for a server so that we can use this information in cell alias detection. Signed-off-by: David Howells

afs: Split the usage count on struct afs_server

2020-05-31T14:19:51+00:00

Split the usage count on the afs_server struct to have an active count that registers who's actually using it separately from the reference count on the object. This allows a future patch to dispatch polling probes without advancing the "unuse" time into the future each time we emit a probe, which would otherwise prevent unused server records from expiring. Included in this: (1) The latter part of afs_destroy_server() in which the RCU destruction of afs_server objects is invoked and the outstanding server count is decremented is split out into __afs_put_server(). (2) afs_put_server() now calls __afs_put_server() rather then setting the management timer. (3) The calls begun by afs_fs_give_up_all_callbacks() and afs_fs_get_capabilities() can now take a ref on the server record, so afs_destroy_server() can just drop its ref and needn't wait for the completion of these calls. They'll put the ref when they're done. (4) Because of (3), afs_fs_probe_done() no longer needs to wake up afs_destroy_server() with server->probe_outstanding. (5) afs_gc_servers can be simplified. It only needs to check if server->active is 0 rather than playing games with the refcount. (6) afs_manage_servers() can propose a server for gc if usage == 0 rather than if ref == 1. The gc is effected by (5). Signed-off-by: David Howells

afs: Use the serverUnique field in the UVLDB record to reduce rpc ops

2020-05-31T14:19:51+00:00

The U-version VLDB volume record retrieved by the VL.GetEntryByNameU rpc op carries a change counter (the serverUnique field) for each fileserver listed in the record as backing that volume. This is incremented whenever the registration details for a fileserver change (such as its address list). Note that the same value will be seen in all UVLDB records that refer to that fileserver. This should be checked before calling the VL server to re-query the address list for a fileserver. If it's the same, there's no point doing the query. Reported-by: Jeffrey Altman Signed-off-by: David Howells

Merge tag 'afs-next-20190628' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

2019-07-11T03:55:33+00:00

Pull afs updates from David Howells: "A set of minor changes for AFS: - Remove an unnecessary check in afs_unlink() - Add a tracepoint for tracking callback management - Add a tracepoint for afs_server object usage - Use struct_size() - Add mappings for AFS UAE abort codes to Linux error codes, using symbolic names rather than hex numbers in the .c file" * tag 'afs-next-20190628' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Add support for the UAE error table fs/afs: use struct_size() in kzalloc() afs: Trace afs_server usage afs: Add some callback management tracepoints afs: afs_unlink() doesn't need to check dentry->d_inode

afs: Trace afs_server usage

2019-06-20T17:12:17+00:00

Add a tracepoint (afs_server) to track the afs_server object usage count. Signed-off-by: David Howells

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman