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

timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.

Conversion was done with c

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

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 <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

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afs: Simplify cell record handling

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 th

afs: Simplify cell record handling

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 <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/ # v1
Link: https://lore.kernel.org/r/[email protected]/ # v4

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afs: Fix afs_server ref accounting

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

afs: Fix afs_server ref accounting

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 <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/ # v1
Link: https://lore.kernel.org/r/[email protected]/ # v4

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

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_s

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

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 <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/ # v1
Link: https://lore.kernel.org/r/[email protected]/ # v4

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afs: Improve server refcount/active count tracing

Improve server refcount/active count tracing to distinguish between simply
getting/putting a ref and using/unusing the server record (which changes

afs: Improve server refcount/active count tracing

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 <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/ # v1
Link: https://lore.kernel.org/r/[email protected]/ # v4

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

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 re

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

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 <[email protected]>
cc: Marc Dionne <[email protected]>
cc: Simon Horman <[email protected]>
cc: [email protected]
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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afs: Fix ignored callbacks over ipv4

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

afs: Fix ignored callbacks over ipv4

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 <[email protected]>
Link: https://lists.infradead.org/pipermail/linux-afs/2024-February/008035.html
Signed-off-by: Marc Dionne <[email protected]>
Signed-off-by: David Howells <[email protected]>
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/[email protected]
Signed-off-by: Christian Brauner <[email protected]>

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

Apply server breaks to mmap'd files that are being used from that server
from the call processor work function rather than punting it o

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

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 <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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

Make it possible to find the afs_volume structs that are using an
afs_server struct to aid in breaking volume callbacks.

The way th

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

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 <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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afs: Keep a record of the current fileserver endpoint state

Keep a record of the current fileserver endpoint state, including the probe
state, and replace it when a new probe is started rather than

afs: Keep a record of the current fileserver endpoint state

Keep a record of the current fileserver endpoint state, including the probe
state, and replace it when a new probe is started rather than just
squelching the old state and overwriting it. Clearance of the old state
can cause a race if there's another thread also currently trying to
communicate with that server.

It appears that this race might be the culprit for some occasions where
kafs complains about invalid data in the RPC reply because the rotation
algorithm fell all the way through without actually issuing an RPC call and
the error return got filled in from the probe state (which has a zero error
recorded). Whatever happens to be in the caller's reply buffer is then
taken as the response.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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afs: Fold the afs_addr_cursor struct in

Fold the afs_addr_cursor struct into the afs_operation struct and the
afs_vl_cursor struct and fold its operations into their callers also.

Signed-off-by: Da

afs: Fold the afs_addr_cursor struct in

Fold the afs_addr_cursor struct into the afs_operation struct and the
afs_vl_cursor struct and fold its operations into their callers also.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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afs: Use peer + service_id as call address

Use the rxrpc_peer plus the service ID as the call address instead of
passing in a sockaddr_srx down to rxrpc. The peer record is obtained by
using rxrpc_

afs: Use peer + service_id as call address

Use the rxrpc_peer plus the service ID as the call address instead of
passing in a sockaddr_srx down to rxrpc. The peer record is obtained by
using rxrpc_kernel_get_peer(). This avoids the need to repeatedly look up
the peer and allows rxrpc to hold on to resources for it.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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afs: Add a tracepoint for struct afs_addr_list

Add a tracepoint to track the lifetime of the afs_addr_list struct.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <marc.dionne@au

afs: Add a tracepoint for struct afs_addr_list

Add a tracepoint to track the lifetime of the afs_addr_list struct.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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afs: Simplify error handling

Simplify error handling a bit by moving it from the afs_addr_cursor struct
to the afs_operation and afs_vl_cursor structs and using the error
prioritisation function for

afs: Simplify error handling

Simplify error handling a bit by moving it from the afs_addr_cursor struct
to the afs_operation and afs_vl_cursor structs and using the error
prioritisation function for accumulating errors from multiple sources (AFS
tries to rotate between multiple fileservers, some of which may be
inaccessible or in some state of offlinedness).

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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afs: Wrap most op->error accesses with inline funcs

Wrap most op->error accesses with inline funcs which will make it easier
for a subsequent patch to replace op->error with something else. Two
fun

afs: Wrap most op->error accesses with inline funcs

Wrap most op->error accesses with inline funcs which will make it easier
for a subsequent patch to replace op->error with something else. Two
functions are added to this end:

(1) afs_op_error() - Get the error code.

(2) afs_op_set_error() - Set the error code.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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rxrpc, afs: Allow afs to pin rxrpc_peer objects

Change rxrpc's API such that:

(1) A new function, rxrpc_kernel_lookup_peer(), is provided to look up an
rxrpc_peer record for a remote address

rxrpc, afs: Allow afs to pin rxrpc_peer objects

Change rxrpc's API such that:

(1) A new function, rxrpc_kernel_lookup_peer(), is provided to look up an
rxrpc_peer record for a remote address and a corresponding function,
rxrpc_kernel_put_peer(), is provided to dispose of it again.

(2) When setting up a call, the rxrpc_peer object used during a call is
now passed in rather than being set up by rxrpc_connect_call(). For
afs, this meenat passing it to rxrpc_kernel_begin_call() rather than
the full address (the service ID then has to be passed in as a
separate parameter).

(3) A new function, rxrpc_kernel_remote_addr(), is added so that afs can
get a pointer to the transport address for display purposed, and
another, rxrpc_kernel_remote_srx(), to gain a pointer to the full
rxrpc address.

(4) The function to retrieve the RTT from a call, rxrpc_kernel_get_srtt(),
is then altered to take a peer. This now returns the RTT or -1 if
there are insufficient samples.

(5) Rename rxrpc_kernel_get_peer() to rxrpc_kernel_call_get_peer().

(6) Provide a new function, rxrpc_kernel_get_peer(), to get a ref on a
peer the caller already has.

This allows the afs filesystem to pin the rxrpc_peer records that it is
using, allowing faster lookups and pointer comparisons rather than
comparing sockaddr_rxrpc contents. It also makes it easier to get hold of
the RTT. The following changes are made to afs:

(1) The addr_list struct's addrs[] elements now hold a peer struct pointer
and a service ID rather than a sockaddr_rxrpc.

(2) When displaying the transport address, rxrpc_kernel_remote_addr() is
used.

(3) The port arg is removed from afs_alloc_addrlist() since it's always
overridden.

(4) afs_merge_fs_addr4() and afs_merge_fs_addr6() do peer lookup and may
now return an error that must be handled.

(5) afs_find_server() now takes a peer pointer to specify the address.

(6) afs_find_server(), afs_compare_fs_alists() and afs_merge_fs_addr[46]{}
now do peer pointer comparison rather than address comparison.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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afs: Turn the afs_addr_list address array into an array of structs

Turn the afs_addr_list address array into an array of structs, thereby
allowing per-address (such as RTT) info to be added.

Signed

afs: Turn the afs_addr_list address array into an array of structs

Turn the afs_addr_list address array into an array of structs, thereby
allowing per-address (such as RTT) info to be added.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]

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afs: fix the usage of read_seqbegin_or_lock() in afs_find_server*()

David Howells says:

(5) afs_find_server().

There could be a lot of servers in the list and each server can have
multi

afs: fix the usage of read_seqbegin_or_lock() in afs_find_server*()

David Howells says:

(5) afs_find_server().

There could be a lot of servers in the list and each server can have
multiple addresses, so I think this would be better with an exclusive
second pass.

The server list isn't likely to change all that often, but when it does
change, there's a good chance several servers are going to be
added/removed one after the other. Further, this is only going to be
used for incoming cache management/callback requests from the server,
which hopefully aren't going to happen too often - but it is remotely
drivable.

(6) afs_find_server_by_uuid().

Similarly to (5), there could be a lot of servers to search through, but
they are in a tree not a flat list, so it should be faster to process.
Again, it's not likely to change that often and, again, when it does
change it's likely to involve multiple changes. This can be driven
remotely by an incoming cache management request but is mostly going to
be driven by setting up or reconfiguring a volume's server list -
something that also isn't likely to happen often.

Make the "seq" counter odd on the 2nd pass, otherwise read_seqbegin_or_lock()
never takes the lock.

Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/

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afs: Fix server->active leak in afs_put_server

The atomic_read was accidentally replaced with atomic_inc_return,
which prevents the server from getting cleaned up and causes rmmod
to hang with a war

afs: Fix server->active leak in afs_put_server

The atomic_read was accidentally replaced with atomic_inc_return,
which prevents the server from getting cleaned up and causes rmmod
to hang with a warning:

Can't purge s=00000001

Fixes: 2757a4dc1849 ("afs: Fix access after dec in put functions")
Signed-off-by: Marc Dionne <[email protected]>
Signed-off-by: David Howells <[email protected]>
Link: https://lore.kernel.org/r/[email protected]/
Signed-off-by: Linus Torvalds <[email protected]>

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afs: Fix access after dec in put functions

Reference-putting functions should not access the object being put after
decrementing the refcount unless they reduce the refcount to zero.

Fix a couple o

afs: Fix access after dec in put functions

Reference-putting functions should not access the object being put after
decrementing the refcount unless they reduce the refcount to zero.

Fix a couple of instances of this in afs by copying the information to be
logged by tracepoint to local variables before doing the decrement.

[Fixed a bit in afs_put_server() that I'd missed but Marc caught]

Fixes: 341f741f04be ("afs: Refcount the afs_call struct")
Fixes: 452181936931 ("afs: Trace afs_server usage")
Fixes: 977e5f8ed0ab ("afs: Split the usage count on struct afs_server")
Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/165911278430.3745403.16526310736054780645.stgit@warthog.procyon.org.uk/ # v1

show more ...

afs: Use refcount_t rather than atomic_t

Use refcount_t rather than atomic_t in afs to make use of the count
checking facilities provided.

Signed-off-by: David Howells <[email protected]>
Reviewe

afs: Use refcount_t rather than atomic_t

Use refcount_t rather than atomic_t in afs to make use of the count
checking facilities provided.

Signed-off-by: David Howells <[email protected]>
Reviewed-by: Marc Dionne <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/165911277768.3745403.423349776836296452.stgit@warthog.procyon.org.uk/ # v1

show more ...

afs: Fix mmap coherency vs 3rd-party changes

Fix the coherency management of mmap'd data such that 3rd-party changes
become visible as soon as possible after the callback notification is
delivered b

afs: Fix mmap coherency vs 3rd-party changes

Fix the coherency management of mmap'd data such that 3rd-party changes
become visible as soon as possible after the callback notification is
delivered by the fileserver. This is done by the following means:

(1) When we break a callback on a vnode specified by the CB.CallBack call
from the server, we queue a work item (vnode->cb_work) to go and
clobber all the PTEs mapping to that inode.

This causes the CPU to trip through the ->map_pages() and
->page_mkwrite() handlers if userspace attempts to access the page(s)
again.

(Ideally, this would be done in the service handler for CB.CallBack,
but the server is waiting for our reply before considering, and we
have a list of vnodes, all of which need breaking - and the process of
getting the mmap_lock and stripping the PTEs on all CPUs could be
quite slow.)

(2) Call afs_validate() from the ->map_pages() handler to check to see if
the file has changed and to get a new callback promise from the
server.

Also handle the fileserver telling us that it's dropping all callbacks,
possibly after it's been restarted by sending us a CB.InitCallBackState*
call by the following means:

(3) Maintain a per-cell list of afs files that are currently mmap'd
(cell->fs_open_mmaps).

(4) Add a work item to each server that is invoked if there are any open
mmaps when CB.InitCallBackState happens. This work item goes through
the aforementioned list and invokes the vnode->cb_work work item for
each one that is currently using this server.

This causes the PTEs to be cleared, causing ->map_pages() or
->page_mkwrite() to be called again, thereby calling afs_validate()
again.

I've chosen to simply strip the PTEs at the point of notification reception
rather than invalidate all the pages as well because (a) it's faster, (b)
we may get a notification for other reasons than the data being altered (in
which case we don't want to clobber the pagecache) and (c) we need to ask
the server to find out - and I don't want to wait for the reply before
holding up userspace.

This was tested using the attached test program:

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
int main(int argc, char *argv[])
{
size_t size = getpagesize();
unsigned char *p;
bool mod = (argc == 3);
int fd;
if (argc != 2 && argc != 3) {
fprintf(stderr, "Format: %s <file> [mod]\n", argv[0]);
exit(2);
}
fd = open(argv[1], mod ? O_RDWR : O_RDONLY);
if (fd < 0) {
perror(argv[1]);
exit(1);
}

p = mmap(NULL, size, mod ? PROT_READ|PROT_WRITE : PROT_READ,
MAP_SHARED, fd, 0);
if (p == MAP_FAILED) {
perror("mmap");
exit(1);
}
for (;;) {
if (mod) {
p[0]++;
msync(p, size, MS_ASYNC);
fsync(fd);
}
printf("%02x", p[0]);
fflush(stdout);
sleep(1);
}
}

It runs in two modes: in one mode, it mmaps a file, then sits in a loop
reading the first byte, printing it and sleeping for a second; in the
second mode it mmaps a file, then sits in a loop incrementing the first
byte and flushing, then printing and sleeping.

Two instances of this program can be run on different machines, one doing
the reading and one doing the writing. The reader should see the changes
made by the writer, but without this patch, they aren't because validity
checking is being done lazily - only on entry to the filesystem.

Testing the InitCallBackState change is more complicated. The server has
to be taken offline, the saved callback state file removed and then the
server restarted whilst the reading-mode program continues to run. The
client machine then has to poke the server to trigger the InitCallBackState
call.

Signed-off-by: David Howells <[email protected]>
Tested-by: Markus Suvanto <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/163111668833.283156.382633263709075739.stgit@warthog.procyon.org.uk/

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afs: Don't assert on unpurgeable server records

Don't give an assertion failure on unpurgeable afs_server records - which
kills the thread - but rather emit a trace line when we are purging a
record

afs: Don't assert on unpurgeable server records

Don't give an assertion failure on unpurgeable afs_server records - which
kills the thread - but rather emit a trace line when we are purging a
record (which only happens during network namespace removal or rmmod) and
print a notice of the problem.

Signed-off-by: David Howells <[email protected]>

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afs: Fix hang on rmmod due to outstanding timer

The fileserver probe timer, net->fs_probe_timer, isn't cancelled when
the kafs module is being removed and so the count it holds on
net->servers_outst

afs: Fix hang on rmmod due to outstanding timer

The fileserver probe timer, net->fs_probe_timer, isn't cancelled when
the kafs module is being removed and so the count it holds on
net->servers_outstanding doesn't get dropped..

This causes rmmod to wait forever. The hung process shows a stack like:

afs_purge_servers+0x1b5/0x23c [kafs]
afs_net_exit+0x44/0x6e [kafs]
ops_exit_list+0x72/0x93
unregister_pernet_operations+0x14c/0x1ba
unregister_pernet_subsys+0x1d/0x2a
afs_exit+0x29/0x6f [kafs]
__do_sys_delete_module.isra.0+0x1a2/0x24b
do_syscall_64+0x51/0x95
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by:

(1) Attempting to cancel the probe timer and, if successful, drop the
count that the timer was holding.

(2) Make the timer function just drop the count and not schedule the
prober if the afs portion of net namespace is being destroyed.

Also, whilst we're at it, make the following changes:

(3) Initialise net->servers_outstanding to 1 and decrement it before
waiting on it so that it doesn't generate wake up events by being
decremented to 0 until we're cleaning up.

(4) Switch the atomic_dec() on ->servers_outstanding for ->fs_timer in
afs_purge_servers() to use the helper function for that.

Fixes: f6cbb368bcb0 ("afs: Actively poll fileservers to maintain NAT or firewall openings")
Signed-off-by: David Howells <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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afs: Don't use probe running state to make decisions outside probe code

Don't use the running state for fileserver probes to make decisions about
which server to use as the state is cleared at the s

afs: Don't use probe running state to make decisions outside probe code

Don't use the running state for fileserver probes to make decisions about
which server to use as the state is cleared at the start of a probe and
also intermediate values might be misleading.

Instead, add a separate 'latest known' rtt in the afs_server struct and a
flag to indicate if the server is known to be responding and update these
as and when we know what to change them to.

Signed-off-by: David Howells <[email protected]>

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