fuse: add helpers for EIO return value with kernel message

Conditions are triggered by a buggy fuse server will result in -EIO which
is hard to interpret without any context.

Add helpers that print a short message to the kernel log as well as
returning the error value.  This serves a dual purpose:

 - documents the error condition inside the code

 - allows the implementor of the fuse server to get the context for the
   error

Some debug messages are removed in favor of this.

This also changes the mmap return value from -ETXTBSY to -ENODEV if a
passthrough open raced with the prior check.  This makes both cases return
-ENODEV if the file is in passthrough mode.

Additionally change the return value of fuse_file_cached_io_open() from an
error value to a bool (true on success) as the error value is translated
anyway.

Currently these use the pr_notice_once() variant.  Possibly should be
changed to a ratelimit of e.g. once per minute.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

0 files changed, 0 insertions, 0 deletions