fscontext: do not consume log entries when returning -EMSGSIZE

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commit 72d271a7ba upstream.

Userspace generally expects APIs that return -EMSGSIZE to allow for them
to adjust their buffer size and retry the operation. However, the
fscontext log would previously clear the message even in the -EMSGSIZE
case.

Given that it is very cheap for us to check whether the buffer is too
small before we remove the message from the ring buffer, let's just do
that instead. While we're at it, refactor some fscontext_read() into a
separate helper to make the ring buffer logic a bit easier to read.

Fixes: 007ec26cdc ("vfs: Implement logging through fs_context")
Cc: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/20250807-fscontext-log-cleanups-v3-1-8d91d6242dc3@cyphar.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Aleksa Sarai 2025-08-07 03:55:23 +10:00 • committed by Greg Kroah-Hartman

parent 34451f435c

commit b8f70f9479

1 changed files with 38 additions and 32 deletions

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fs/fsopen.c

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