kernel/git/stable/linux.git/fs/afs/cell.c, branch linux-5.3.y

afs: Fix leak in afs_lookup_cell_rcu()

2019-08-22T12:33:26+00:00

Fix a leak on the cell refcount in afs_lookup_cell_rcu() due to non-clearance of the default error in the case a NULL cell name is passed and the workstation default cell is used. Also put a bit at the end to make sure we don't leak a cell ref if we're going to be returning an error. This leak results in an assertion like the following when the kafs module is unloaded: AFS: Assertion failed 2 == 1 is false 0x2 == 0x1 is false ------------[ cut here ]------------ kernel BUG at fs/afs/cell.c:770! ... RIP: 0010:afs_manage_cells+0x220/0x42f [kafs] ... process_one_work+0x4c2/0x82c ? pool_mayday_timeout+0x1e1/0x1e1 ? do_raw_spin_lock+0x134/0x175 worker_thread+0x336/0x4a6 ? rescuer_thread+0x4af/0x4af kthread+0x1de/0x1ee ? kthread_park+0xd4/0xd4 ret_from_fork+0x24/0x30 Fixes: 989782dcdc91 ("afs: Overhaul cell database management") 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

afs: Fix cell DNS lookup

2019-05-16T11:58:23+00:00

Currently, once configured, AFS cells are looked up in the DNS at regular intervals - which is a waste of resources if those cells aren't being used. It also leads to a problem where cells preloaded, but not configured, before the network is brought up end up effectively statically configured with no VL servers and are unable to get any. Fix this by not doing the DNS lookup until the first time a cell is touched. It is waited for if we don't have any cached records yet, otherwise the DNS lookup to maintain the record is done in the background. This has the downside that the first time you touch a cell, you now have to wait for the upcall to do the required DNS lookups rather than them already being cached. Further, the record is not replaced if the old record has at least one server in it and the new record doesn't have any. Fixes: 0a5143f2f89c ("afs: Implement VL server rotation") Signed-off-by: David Howells

afs: Fix afs_cell records to always have a VL server list record

2019-05-15T16:35:53+00:00

Fix it such that afs_cell records always have a VL server list record attached, even if it's a dummy one, so that various checks can be removed. Signed-off-by: David Howells

afs: Fix missing lock when replacing VL server list

2019-05-15T16:35:53+00:00

When afs_update_cell() replaces the cell->vl_servers list, it uses RCU protocol so that proc is protected, but doesn't take ->vl_servers_lock to protect afs_start_vl_iteration() (which does actually take a shared lock). Fix this by making afs_update_cell() take an exclusive lock when replacing ->vl_servers. Fixes: 0a5143f2f89c ("afs: Implement VL server rotation") Signed-off-by: David Howells

afs: Fix manually set volume location server list

2019-02-25T19:59:07+00:00

When a cell with a volume location server list is added manually by echoing the details into /proc/net/afs/cells, a record is added but the flag saying it has been looked up isn't set. This causes the VL server rotation code to wait forever, with the top of /proc/pid/stack looking like: afs_select_vlserver+0x3a6/0x6f3 afs_vl_lookup_vldb+0x4b/0x92 afs_create_volume+0x25/0x1b9 ... with the thread stuck in afs_start_vl_iteration() waiting for AFS_CELL_FL_NO_LOOKUP_YET to be cleared. Fix this by clearing AFS_CELL_FL_NO_LOOKUP_YET when setting up a record if that record's details were supplied manually. Fixes: 0a5143f2f89c ("afs: Implement VL server rotation") Reported-by: Dave Botsch Signed-off-by: David Howells Signed-off-by: Linus Torvalds

afs: Fix TTL on VL server and address lists

2018-10-23T23:41:07+00:00

Currently the TTL on VL server and address lists isn't set in all circumstances and may be set to poor choices in others, since the TTL is derived from the SRV/AFSDB DNS record if and when available. Fix the TTL by limiting the range to a minimum and maximum from the current time. At some point these can be made into sysctl knobs. Further, use the TTL we obtained from the upcall to set the expiry on negative results too; in future a mechanism can be added to force reloading of such data. Signed-off-by: David Howells

afs: Implement VL server rotation

2018-10-23T23:41:07+00:00

Track VL servers as independent entities rather than lumping all their addresses together into one set and implement server-level rotation by: (1) Add the concept of a VL server list, where each server has its own separate address list. This code is similar to the FS server list. (2) Use the DNS resolver to retrieve a set of servers and their associated addresses, ports, preference and weight ratings. (3) In the case of a legacy DNS resolver or an address list given directly through /proc/net/afs/cells, create a list containing just a dummy server record and attach all the addresses to that. (4) Implement a simple rotation policy, for the moment ignoring the priorities and weights assigned to the servers. (5) Show the address list through /proc/net/afs//vlservers. This also displays the source and status of the data as indicated by the upcall. Signed-off-by: David Howells

afs: Fix cell proc list

2018-10-12T11:18:57+00:00

Access to the list of cells by /proc/net/afs/cells has a couple of problems: (1) It should be checking against SEQ_START_TOKEN for the keying the header line. (2) It's only holding the RCU read lock, so it can't just walk over the list without following the proper RCU methods. Fix these by using an hlist instead of an ordinary list and using the appropriate accessor functions to follow it with RCU. Since the code that adds a cell to the list must also necessarily change, sort the list on insertion whilst we're at it. Fixes: 989782dcdc91 ("afs: Overhaul cell database management") Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman

afs: Display manually added cells in dynamic root mount

2018-06-15T14:27:09+00:00

Alter the dynroot mount so that cells created by manipulation of /proc/fs/afs/cells and /proc/fs/afs/rootcell and by specification of a root cell as a module parameter will cause directories for those cells to be created in the dynamic root superblock for the network namespace[*]. To this end: (1) Only one dynamic root superblock is now created per network namespace and this is shared between all attempts to mount it. This makes it easier to find the superblock to modify. (2) When a dynamic root superblock is created, the list of cells is walked and directories created for each cell already defined. (3) When a new cell is added, if a dynamic root superblock exists, a directory is created for it. (4) When a cell is destroyed, the directory is removed. (5) These directories are created by calling lookup_one_len() on the root dir which automatically creates them if they don't exist. [*] Inasmuch as network namespaces are currently supported here. Signed-off-by: David Howells