linux.git/fs/afs, branch v5.15.104

afs: Fix lost servers_outstanding count

2022-12-31T12:14:45+00:00

[ Upstream commit 36f82c93ee0bd88f1c95a52537906b8178b537f1 ]

The afs_fs_probe_dispatcher() work function is passed a count on
net->servers_outstanding when it is scheduled (which may come via its
timer).  This is passed back to the work_item, passed to the timer or
dropped at the end of the dispatcher function.

But, at the top of the dispatcher function, there are two checks which
skip the rest of the function: if the network namespace is being destroyed
or if there are no fileservers to probe.  These two return paths, however,
do not drop the count passed to the dispatcher, and so, sometimes, the
destruction of a network namespace, such as induced by rmmod of the kafs
module, may get stuck in afs_purge_servers(), waiting for
net->servers_outstanding to become zero.

Fix this by adding the missing decrements in afs_fs_probe_dispatcher().

Fixes: f6cbb368bcb0 ("afs: Actively poll fileservers to maintain NAT or firewall openings")
Reported-by: Marc Dionne 
Signed-off-by: David Howells 
Tested-by: Marc Dionne 
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/167164544917.2072364.3759519569649459359.stgit@warthog.procyon.org.uk/
Signed-off-by: Sasha Levin

afs: Fix fileserver probe RTT handling

2022-12-08T10:28:41+00:00

[ Upstream commit ca57f02295f188d6c65ec02202402979880fa6d8 ]

The fileserver probing code attempts to work out the best fileserver to
use for a volume by retrieving the RTT calculated by AF_RXRPC for the
probe call sent to each server and comparing them.  Sometimes, however,
no RTT estimate is available and rxrpc_kernel_get_srtt() returns false,
leading good fileservers to be given an RTT of UINT_MAX and thus causing
the rotation algorithm to ignore them.

Fix afs_select_fileserver() to ignore rxrpc_kernel_get_srtt()'s return
value and just take the estimated RTT it provides - which will be capped
at 1 second.

Fixes: 1d4adfaf6574 ("rxrpc: Make rxrpc_kernel_get_srtt() indicate validity")
Signed-off-by: David Howells 
Reviewed-by: Marc Dionne 
Tested-by: Marc Dionne 
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/166965503999.3392585.13954054113218099395.stgit@warthog.procyon.org.uk/
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

afs: Return -EAGAIN, not -EREMOTEIO, when a file already locked

2022-09-23T12:15:51+00:00

[ Upstream commit 0066f1b0e27556381402db3ff31f85d2a2265858 ]

When trying to get a file lock on an AFS file, the server may return
UAEAGAIN to indicate that the lock is already held.  This is currently
translated by the default path to -EREMOTEIO.

Translate it instead to -EAGAIN so that we know we can retry it.

Signed-off-by: David Howells 
Reviewed-by: Jeffrey E Altman 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/166075761334.3533338.2591992675160918098.stgit@warthog.procyon.org.uk/
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

afs: Use the operation issue time instead of the reply time for callbacks

2022-09-15T09:30:05+00:00

[ Upstream commit 7903192c4b4a82d792cb0dc5e2779a2efe60d45b ]

rxrpc and kafs between them try to use the receive timestamp on the first
data packet (ie. the one with sequence number 1) as a base from which to
calculate the time at which callback promise and lock expiration occurs.

However, we don't know how long it took for the server to send us the reply
from it having completed the basic part of the operation - it might then,
for instance, have to send a bunch of a callback breaks, depending on the
particular operation.

Fix this by using the time at which the operation is issued on the client
as a base instead.  That should never be longer than the server's idea of
the expiry time.

Fixes: 781070551c26 ("afs: Fix calculation of callback expiry time")
Fixes: 2070a3e44962 ("rxrpc: Allow the reply time to be obtained on a client call")
Suggested-by: Jeffrey E Altman 
Signed-off-by: David Howells 
Signed-off-by: Sasha Levin

afs: Fix dynamic root getattr

2022-06-29T07:03:25+00:00

[ Upstream commit cb78d1b5efffe4cf97e16766329dd7358aed3deb ]

The recent patch to make afs_getattr consult the server didn't account
for the pseudo-inodes employed by the dynamic root-type afs superblock
not having a volume or a server to access, and thus an oops occurs if
such a directory is stat'd.

Fix this by checking to see if the vnode->volume pointer actually points
anywhere before following it in afs_getattr().

This can be tested by stat'ing a directory in /afs.  It may be
sufficient just to do "ls /afs" and the oops looks something like:

        BUG: kernel NULL pointer dereference, address: 0000000000000020
        ...
        RIP: 0010:afs_getattr+0x8b/0x14b
        ...
        Call Trace:
         
         vfs_statx+0x79/0xf5
         vfs_fstatat+0x49/0x62

Fixes: 2aeb8c86d499 ("afs: Fix afs_getattr() to refetch file status if callback break occurred")
Reported-by: Marc Dionne 
Signed-off-by: David Howells 
Reviewed-by: Marc Dionne 
Tested-by: Marc Dionne 
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/165408450783.1031787.7941404776393751186.stgit@warthog.procyon.org.uk/
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

afs: Fix infinite loop found by xfstest generic/676

2022-06-14T16:36:13+00:00

[ Upstream commit 17eabd42560f4636648ad65ba5b20228071e2363 ]

In AFS, a directory is handled as a file that the client downloads and
parses locally for the purposes of performing lookup and getdents
operations.  The in-kernel afs filesystem has a number of functions that
do this.

A directory file is arranged as a series of 2K blocks divided into
32-byte slots, where a directory entry occupies one or more slots, plus
each block starts with one or more metadata blocks.

When parsing a block, if the last slots are occupied by a dirent that
occupies more than a single slot and the file position points at a slot
that's not the initial one, the logic in afs_dir_iterate_block() that
skips over it won't advance the file pointer to the end of it.  This
will cause an infinite loop in getdents() as it will keep retrying that
block and failing to advance beyond the final entry.

Fix this by advancing the file pointer if the next entry will be beyond
it when we skip a block.

This was found by the generic/676 xfstest but can also be triggered with
something like:

	~/xfstests-dev/src/t_readdir_3 /xfstest.test/z 4000 1

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: David Howells 
Reviewed-by: Marc Dionne 
Tested-by: Marc Dionne 
cc: linux-afs@lists.infradead.org
Link: http://lore.kernel.org/r/165391973497.110268.2939296942213894166.stgit@warthog.procyon.org.uk/
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

afs: Adjust ACK interpretation to try and cope with NAT

2022-06-09T08:22:40+00:00

[ Upstream commit adc9613ff66c26ebaff9814973181ac178beb90b ]

If a client's address changes, say if it is NAT'd, this can disrupt an in
progress operation.  For most operations, this is not much of a problem,
but StoreData can be different as some servers modify the target file as
the data comes in, so if a store request is disrupted, the file can get
corrupted on the server.

The problem is that the server doesn't recognise packets that come after
the change of address as belonging to the original client and will bounce
them, either by sending an OUT_OF_SEQUENCE ACK to the apparent new call if
the packet number falls within the initial sequence number window of a call
or by sending an EXCEEDS_WINDOW ACK if it falls outside and then aborting
it.  In both cases, firstPacket will be 1 and previousPacket will be 0 in
the ACK information.

Fix this by the following means:

 (1) If a client call receives an EXCEEDS_WINDOW ACK with firstPacket as 1
     and previousPacket as 0, assume this indicates that the server saw the
     incoming packets from a different peer and thus as a different call.
     Fail the call with error -ENETRESET.

 (2) Also fail the call if a similar OUT_OF_SEQUENCE ACK occurs if the
     first packet has been hard-ACK'd.  If it hasn't been hard-ACK'd, the
     ACK packet will cause it to get retransmitted, so the call will just
     be repeated.

 (3) Make afs_select_fileserver() treat -ENETRESET as a straight fail of
     the operation.

 (4) Prioritise the error code over things like -ECONNRESET as the server
     did actually respond.

 (5) Make writeback treat -ENETRESET as a retryable error and make it
     redirty all the pages involved in a write so that the VM will retry.

Note that there is still a circumstance that I can't easily deal with: if
the operation is fully received and processed by the server, but the reply
is lost due to address change.  There's no way to know if the op happened.
We can examine the server, but a conflicting change could have been made by
a third party - and we can't tell the difference.  In such a case, a
message like:

    kAFS: vnode modified {100058:146266} b7->b8 YFS.StoreData64 (op=2646a)

will be logged to dmesg on the next op to touch the file and the client
will reset the inode state, including invalidating clean parts of the
pagecache.

Reported-by: Marc Dionne 
Signed-off-by: David Howells 
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2021-December/004811.html # v1
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

rxrpc, afs: Fix selection of abort codes

2022-06-09T08:22:40+00:00

[ Upstream commit de696c4784f0706884458893c5a6c39b3a3ff65c ]

The RX_USER_ABORT code should really only be used to indicate that the user
of the rxrpc service (ie. userspace) implicitly caused a call to be aborted
- for instance if the AF_RXRPC socket is closed whilst the call was in
progress.  (The user may also explicitly abort a call and specify the abort
code to use).

Change some of the points of generation to use other abort codes instead:

 (1) Abort the call with RXGEN_SS_UNMARSHAL or RXGEN_CC_UNMARSHAL if we see
     ENOMEM and EFAULT during received data delivery and abort with
     RX_CALL_DEAD in the default case.

 (2) Abort with RXGEN_SS_MARSHAL if we get ENOMEM whilst trying to send a
     reply.

 (3) Abort with RX_CALL_DEAD if we stop hearing from the peer if we had
     heard from the peer and abort with RX_CALL_TIMEOUT if we hadn't.

 (4) Abort with RX_CALL_DEAD if we try to disconnect a call that's not
     completed successfully or been aborted.

Reported-by: Jeffrey Altman 
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

afs: Fix afs_getattr() to refetch file status if callback break occurred

2022-05-25T07:57:37+00:00

[ Upstream commit 2aeb8c86d49967552394d5e723f87454cb53f501 ]

If a callback break occurs (change notification), afs_getattr() needs to
issue an FS.FetchStatus RPC operation to update the status of the file
being examined by the stat-family of system calls.

Fix afs_getattr() to do this if AFS_VNODE_CB_PROMISED has been cleared
on a vnode by a callback break.  Skip this if AT_STATX_DONT_SYNC is set.

This can be tested by appending to a file on one AFS client and then
using "stat -L" to examine its length on a machine running kafs.  This
can also be watched through tracing on the kafs machine.  The callback
break is seen:

     kworker/1:1-46      [001] .....   978.910812: afs_cb_call: c=0000005f YFSCB.CallBack
     kworker/1:1-46      [001] ...1.   978.910829: afs_cb_break: 100058:23b4c:242d2c2 b=2 s=1 break-cb
     kworker/1:1-46      [001] .....   978.911062: afs_call_done:    c=0000005f ret=0 ab=0 [0000000082994ead]

And then the stat command generated no traffic if unpatched, but with
this change a call to fetch the status can be observed:

            stat-4471    [000] .....   986.744122: afs_make_fs_call: c=000000ab 100058:023b4c:242d2c2 YFS.FetchStatus
            stat-4471    [000] .....   986.745578: afs_call_done:    c=000000ab ret=0 ab=0 [0000000087fc8c84]

Fixes: 08e0e7c82eea ("[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC.")
Reported-by: Markus Suvanto 
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org
Tested-by: Markus Suvanto 
Tested-by: kafs-testing+fedora34_64checkkafs-build-496@auristor.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216010
Link: https://lore.kernel.org/r/165308359800.162686.14122417881564420962.stgit@warthog.procyon.org.uk/ # v1
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

afs: Fix mmap

2021-12-22T08:32:45+00:00

[ Upstream commit 1744a22ae948799da7927b53ec97ccc877ff9d61 ]

Fix afs_add_open_map() to check that the vnode isn't already on the list
when it adds it.  It's possible that afs_drop_open_mmap() decremented
the cb_nr_mmap counter, but hadn't yet got into the locked section to
remove it.

Also vnode->cb_mmap_link should be initialised, so fix that too.

Fixes: 6e0e99d58a65 ("afs: Fix mmap coherency vs 3rd-party changes")
Reported-by: kafs-testing+fedora34_64checkkafs-build-300@auristor.com
Suggested-by: Marc Dionne 
Signed-off-by: David Howells 
Tested-by: kafs-testing+fedora34_64checkkafs-build-300@auristor.com
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/686465.1639435380@warthog.procyon.org.uk/ # v1
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin