kernel/linux.git/fs/afs/cmservice.c, branch v6.3

rxrpc: Tidy up abort generation infrastructure

2023-01-06T09:43:32+00:00

Tidy up the abort generation infrastructure in the following ways: (1) Create an enum and string mapping table to list the reasons an abort might be generated in tracing. (2) Replace the 3-char string with the values from (1) in the places that use that to log the abort source. This gets rid of a memcpy() in the tracepoint. (3) Subsume the rxrpc_rx_eproto tracepoint with the rxrpc_abort tracepoint and use values from (1) to indicate the trace reason. (4) Always make a call to an abort function at the point of the abort rather than stashing the values into variables and using goto to get to a place where it reported. The C optimiser will collapse the calls together as appropriate. The abort functions return a value that can be returned directly if appropriate. Note that this extends into afs also at the points where that generates an abort. To aid with this, the afs sources need to #define RXRPC_TRACE_ONLY_DEFINE_ENUMS before including the rxrpc tracing header because they don't have access to the rxrpc internal structures that some of the tracepoints make use of. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org

use less confusing names for iov_iter direction initializers

2022-11-25T18:01:55+00:00

READ/WRITE proved to be actively confusing - the meanings are "data destination, as used with read(2)" and "data source, as used with write(2)", but people keep interpreting those as "we read data from it" and "we write data to it", i.e. exactly the wrong way. Call them ITER_DEST and ITER_SOURCE - at least that is harder to misinterpret... Signed-off-by: Al Viro

afs: Fix access after dec in put functions

2022-08-02T17:21:29+00:00

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 cc: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/165911278430.3745403.16526310736054780645.stgit@warthog.procyon.org.uk/ # v1

afs: Use refcount_t rather than atomic_t

2022-08-02T17:10:11+00:00

Use refcount_t rather than atomic_t in afs to make use of the count checking facilities provided. Signed-off-by: David Howells Reviewed-by: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/165911277768.3745403.423349776836296452.stgit@warthog.procyon.org.uk/ # v1

afs: Fix tracepoint string placement with built-in AFS

2021-07-21T14:08:35+00:00

To quote Alexey[1]: I was adding custom tracepoint to the kernel, grabbed full F34 kernel .config, disabled modules and booted whole shebang as VM kernel. Then did perf record -a -e ... It crashed: general protection fault, probably for non-canonical address 0x435f5346592e4243: 0000 [#1] SMP PTI CPU: 1 PID: 842 Comm: cat Not tainted 5.12.6+ #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 RIP: 0010:t_show+0x22/0xd0 Then reproducer was narrowed to # cat /sys/kernel/tracing/printk_formats Original F34 kernel with modules didn't crash. So I started to disable options and after disabling AFS everything started working again. The root cause is that AFS was placing char arrays content into a section full of _pointers_ to strings with predictable consequences. Non canonical address 435f5346592e4243 is "CB.YFS_" which came from CM_NAME macro. Steps to reproduce: CONFIG_AFS=y CONFIG_TRACING=y # cat /sys/kernel/tracing/printk_formats Fix this by the following means: (1) Add enum->string translation tables in the event header with the AFS and YFS cache/callback manager operations listed by RPC operation ID. (2) Modify the afs_cb_call tracepoint to print the string from the translation table rather than using the string at the afs_call name pointer. (3) Switch translation table depending on the service we're being accessed as (AFS or YFS) in the tracepoint print clause. Will this cause problems to userspace utilities? Note that the symbolic representation of the YFS service ID isn't available to this header, so I've put it in as a number. I'm not sure if this is the best way to do this. (4) Remove the name wrangling (CM_NAME) macro and put the names directly into the afs_call_type structs in cmservice.c. Fixes: 8e8d7f13b6d5a9 ("afs: Add some tracepoints") Reported-by: Alexey Dobriyan (SK hynix) Signed-off-by: David Howells Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Marc Dionne cc: Andrew Morton cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/YLAXfvZ+rObEOdc%2F@localhost.localdomain/ [1] Link: https://lore.kernel.org/r/643721.1623754699@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/162430903582.2896199.6098150063997983353.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162609463957.3133237.15916579353149746363.stgit@warthog.procyon.org.uk/ # v1 (repost) Link: https://lore.kernel.org/r/162610726860.3408253.445207609466288531.stgit@warthog.procyon.org.uk/ # v2

afs: Fix fall-through warnings for Clang

2021-05-25T17:30:34+00:00

In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple warnings by explicitly adding multiple fallthrough pseudo-keywords in places where the code is intended to fall through to the next case. Link: https://github.com/KSPP/linux/issues/115 Signed-off-by: Gustavo A. R. Silva Signed-off-by: David Howells Reviewed-by: Jeffrey Altman cc: linux-afs@lists.infradead.org cc: linux-hardening@vger.kernel.org Link: https://lore.kernel.org/r/51150b54e0b0431a2c401cd54f2c4e7f50e94601.1605896059.git.gustavoars@kernel.org/ # v1 Link: https://lore.kernel.org/r/20210420211615.GA51432@embeddedor/ # v2 Signed-off-by: Linus Torvalds

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

afs: Fix handling of CB.ProbeUuid cache manager op

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

The AFS filesystem driver is handling the CB.ProbeUuid request incorrectly. The UUID presented in the request is that of the cache manager, not the fileserver, so afs_deliver_cb_probe_uuid() shouldn't be using that UUID to look up the server. Fix this by looking up the server by address instead. Signed-off-by: David Howells

afs: Don't get epoch from a server because it may be ambiguous

2020-06-04T14:37:56+00:00

Don't get the epoch from a server, particularly one that we're looking up by UUID, as UUIDs may be ambiguous and may map to more than one server - so we can't draw any conclusions from it. Reported-by: Jeffrey Altman Signed-off-by: David Howells

afs: Remove the error argument from afs_protocol_error()

2020-05-31T14:19:52+00:00

Remove the error argument from afs_protocol_error() as it's always -EBADMSG. Signed-off-by: David Howells