Commit Graph
455 Commits
Author SHA1 Message Date
Joanne KoongandMiklos Szeredi ac7304fa1d fuse: clean up interrupt reading
Clean up interrupt reading logic. Remove passing the pointer to the fuse
request as an arg and make the header initializations more readable.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:20 +02:00
Joanne KoongandMiklos Szeredi 1ca4b8b32e fuse: remove stray newline in fuse_dev_do_read()
Remove stray newline that shouldn't be there.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:20 +02:00
Li WangandMiklos Szeredi 521fed4886 fuse: use READ_ONCE in fuse_chan_num_background()
fuse_chan_num_background() is called without holding fch->bg_lock (for
example from fuse_writepages() to compare against fc->congestion_threshold),
while fch->num_background is updated under bg_lock in dev.c and dev_uring.c.
This is the same locked-write/lockless-read pattern already used for
max_background in fuse_chan_max_background().

Use READ_ONCE() on the read side so that:

- The compiler does not cache or coalesce loads of a value that may change
  concurrently on another CPU.
- Prevent KCSAN from reporting an unexpected race.

Signed-off-by: Li Wang <liwang@kylinos.cn>
Fixes: 670d21c6e1 ("fuse: remove reliance on bdi congestion")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:19 +02:00
Amir GoldsteinandMiklos Szeredi e0dcd3f02c fuse: add fuse_request_sent tracepoint
This new tracepoint complements fuse_request_send (enqueue) and
fuse_request_end (completion).  It fires after the request has been
successfully copied to the daemon's buffer, just before the daemon
can start to process it.

fuse_request_sent does not fire if the copy of the request fails.
It also does not fire for NOTIFY_REPLY, which fires the _end tracepoint
at the end of copy.

This is needed for tools tracking the in-flight state of user initiated
fuse requests.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:19 +02:00
Tim BirdandMiklos Szeredi 9f3e7166aa fuse: Add SPDX ID lines to some files
Some fuse source files are missing SPDX-License-Identifier
lines. Add appropriate IDs to these files, and remove old
license references from the headers.

Signed-off-by: Tim Bird <tim.bird@sony.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:19 +02:00
Joanne KoongandMiklos Szeredi 6bd421b499 fuse: remove redundant buffer size checks for interrupt and forget requests
In fuse_dev_do_read(), there is already logic that ensures the buffer is
a minimum of at least FUSE_MIN_READ_BUFFER (8k) bytes.

This makes the buffer size checks for interrupt and forget requests
redundant as sizeof(struct fuse_in_header) + sizeof(struct
fuse_interrupt_in) and sizeof(struct fuse_in_header) + sizeof(struct
fuse_forget_in) are both less than FUSE_MIN_READ_BUFFER.

We can get rid of these checks.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:19 +02:00
Miklos Szeredi a636077231 fuse: simplify fuse_dev_ioctl_clone()
Don't need to check if the new device file is already initialized, since
fuse_dev_install_with_pq() will do that anyway.

Make fuse_dev_install_with_pq() return a boolean value indicating success so
that fuse_dev_ioctl_clone() can return an error in case of failure.

Move aborting the connection (setting fc->connected to zero) to
fuse_dev_install(), because it is not needed when the clone ioctl fails.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:18 +02:00
Miklos Szeredi 48649c0603 fuse: alloc pqueue before installing fch in fuse_dev
Prior to this patchset, fuse_dev (containing fuse_pqueue) was allocated on
mount.  But now fuse_dev is allocated when opening /dev/fuse, even though
the queues are not needed at that time.

Delay allocation of the pqueue (4k worth of list_head) just before mounting
or cloning a device.

Various distributions (e.g. Debian/Fedora) configure /dev/fuse as world
writable, so the pqueue allocation should be deferred to a privileged
operation (mount) to prevent unprivileged userspace from consuming pinned
kernel memory.

[Li Wang: fix kernel NULL pointer dereference in fuse_uring_add_to_pq()]
[Fix race in fuse_dev_release()]

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:18 +02:00
Miklos Szeredi c0f817320d fuse: remove #include "fuse_i.h" from dev.c and dev_uring.c
Move a couple of function declarations from fuse_i.h to dev.h and
fuse_dev_i.h.

Add fuse_conn_get_id() helper that retrieves the connection ID (s_dev) from
fuse_conn.

With the exception of cuse.c, virtio_fs.c and trace.c source files now
either include fuse_i.h or fuse_dev_i/dev_uring_i.h but not both.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:18 +02:00
Miklos Szeredi e582371be4 fuse: remove fuse_mutex protection from fuse_dev_ioctl_sync_init()
In normal use ioctl(FUSE_DEV_IOC_SYNC_INIT) comes before the mount() or
fsconfig() syscalls, they are executed strictly serially.

If ioctl and mount are performed in parallel, the behavior is
nondeterministic.  Removing the mutex does not change this.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:18 +02:00
Miklos Szeredi ff572265f2 fuse: set params in fuse_chan_set_initialized()
Set minor, max_write and max_pages in the fuse_chan.  These match the same
fields in fuse_conn but are needed in both layers.

[Dongyang Jin: Pointers should use NULL instead of explicit '0']

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:17 +02:00
Miklos Szeredi ca46a4aca6 fuse: create notify.c
Move FUSE_NOTIFY_* handling into a separate source file.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:17 +02:00
Miklos Szeredi b8b072cbaf fuse: create poll.c
Move f_op->poll related functions to the new source file.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:17 +02:00
Miklos Szeredi 994d807943 fuse: change fud->fc to fud->chan
Store pointer to struct fuse_chan instead of struct fuse_conn in fuse_dev.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:17 +02:00
Miklos Szeredi 794e811d14 fuse: split out filesystem part of request sending
Create a new source file: req.c and add the request sending entry
functions:

  __fuse_simple_request()
  fuse_simple_background()
  fuse_simple_notify_reply()

Introduce transport layer sending functions that are called by the
respective fs layer function:

  fuse_chan_send()
  fuse_chan_send_bg()
  fuse_chan_send_notify_reply()

Move calculation of request header fields uid, gid and pid from
fuse_get_req() and fuse_force_creads() to a new helper: fuse_fill_creds().

These fileds are now passed to the transport layer via struct fuse_args.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:17 +02:00
Miklos Szeredi 28d733cc3e fuse: change req->fm to req->chan
Store a struct fuse_chan pointer in fuse_req instead of a struct fuse_mount
pointer.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:17 +02:00
Miklos Szeredi a697d95fcd fuse: remove fm arg of args->end callback
Only used by FUSE_INIT and CUSE_INIT, these can store the relevant pointer
in their structs derived from fuse_args.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:17 +02:00
Miklos Szeredi 4eeb5e6cb0 fuse: abort related layering cleanup
- rename fuse_abort_conn() to fuse_chan_abort(), pass fuse_chan pointer
   instead of fuse_conn

 - pass an abort_with_err argument that tells fuse_dev_(read|write) to
   return with ECONNABORTED instead of ENODEV

 - move fc->aborted to fch->abort_with_err

 - rename fuse_wait_aborted() to fuse_chan_wait_aborted()

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:17 +02:00
Miklos Szeredi d1f2721f8c fuse: remove #include "fuse_i.h" from "dev_uring_i.h"
Start getting rid of fs layer stuff from transport layer files.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:16 +02:00
Miklos Szeredi 3344b7367a fuse: move fuse_dev_waitq to dev.c
Move wake_up_all(&fuse_dev_waitq) into fuse_dev_install() where it
logically belongs.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:16 +02:00
Miklos Szeredi 4f5f0038d6 fuse: move forget related struct and helpers
Move:
 - struct fuse_forget_link to fuse_dev_i.h
 - fuse_alloc_forget() to dev.c/dev.h

Rename:
 - fuse_queue_forget -> fuse_chan_queue_forget

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:16 +02:00
Miklos Szeredi b6d83d4e3e fuse: don't access transport layer structs directly from the fs layer
Add helpers (get and set functions mainly) that cleanly separate the
layers.

Remove #include "fuse_dev_i.h" from:

 - inode.c
 - file.c
 - control.c

Remove #include "dev_uring_i.h" from inode.c.

[Li Wang: drop redundant initializer in process_init_limits()]

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:16 +02:00
Miklos Szeredi 56b4332e12 fuse: move request timeout to fuse_chan
Move:

 - timeout

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:16 +02:00
Miklos Szeredi bf9932623d fuse: split off fch->lock from fc->lock
And document which members they protect.

end_polls() is called with both, outer fch->lock is probably unnecessary,
but doesn't hurt for now.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:16 +02:00
Miklos Szeredi 36b6a1e5ed fuse: move interrupt related members to fuse_chan
Move:

 - no_interrupt

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2026-06-15 14:06:16 +02:00