We now read the line from the buffer atomically, which means we have to
allow the buffer to grow past STDIO_REDIRECT_BUFSIZE if we're waiting
for a full line - this behaviour is necessary for
stdio_redirect_readline_timeout() in the next patch.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a flush op, to return the exit code via close().
Also update bcachefs usage to use this to return fsck exit codes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Make it so that a thread_with_stdio user can handle ioctls against the
file descriptor.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Create an ops structure so we can add more file-based functionality in
the next few patches.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Experimentally fix some problems with stdio_redirect_vprintf by creating
a MOO variant with which we can experiment. We can't do a GFP_KERNEL
allocation while holding the spinlock, and I don't like how the printf
function can silently truncate the output if memory allocation fails.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Create a new run_thread_with_stdout function that opens a file in
O_RDONLY mode so that the kernel can write things to userspace but
userspace cannot write to the kernel. This will be used to convey xfs
health event information to userspace.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This fixes a bug where we'd return data without waiting for a newline,
if data was present but a newline was not.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Move the cleanup code to a wrapper function, where we can call it after
the thread_with_stdio fn exits.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
- eliminate the dependency on printbufs, so that we can lift
thread_with_file for use in xfs
- add a nonblocking parameter to stdio_redirect_printf(), and either
block if the buffer is full or drop it on the floor - don't buffer
infinitely
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The output buffer lock has to be a spinlock so that we can write to it
from interrupt context, so we can't use a direct copy_to_user; this
switches thread_with_file_read() to use fault_in_writeable() and
copy_to_user_nofault(), similar to how thread_with_file_write() works.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Calling fd_install() makes a file reachable for userland, including the
possibility to close the file descriptor, which leads to calling its
'release' hook. If that happens before the code had a chance to bump the
reference of the newly created task struct, the release callback will
call put_task_struct() too early, leading to the premature destruction
of the kernel thread.
Avoid that race by calling fd_install() later, after all the setup is
done.
Fixes: 1c6fdbd8f2 ("bcachefs: Initial commit")
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
