kernel/linux.git/fs/fuse/dev.c, branch v7.2-rc1

fuse: clean up interrupt reading

2026-06-15T12:06:20+00:00

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 Signed-off-by: Miklos Szeredi

fuse: remove stray newline in fuse_dev_do_read()

2026-06-15T12:06:20+00:00

Remove stray newline that shouldn't be there. Signed-off-by: Joanne Koong Signed-off-by: Miklos Szeredi

fuse: use READ_ONCE in fuse_chan_num_background()

2026-06-15T12:06:19+00:00

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 Fixes: 670d21c6e17f ("fuse: remove reliance on bdi congestion") Signed-off-by: Miklos Szeredi

fuse: add fuse_request_sent tracepoint

2026-06-15T12:06:19+00:00

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 Reviewed-by: Joanne Koong Signed-off-by: Miklos Szeredi

fuse: Add SPDX ID lines to some files

2026-06-15T12:06:19+00:00

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 Signed-off-by: Miklos Szeredi

fuse: remove redundant buffer size checks for interrupt and forget requests

2026-06-15T12:06:19+00:00

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 Signed-off-by: Miklos Szeredi

fuse: simplify fuse_dev_ioctl_clone()

2026-06-15T12:06:18+00:00

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

fuse: alloc pqueue before installing fch in fuse_dev

2026-06-15T12:06:18+00:00

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

fuse: remove #include "fuse_i.h" from dev.c and dev_uring.c

2026-06-15T12:06:18+00:00

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

fuse: remove fuse_mutex protection from fuse_dev_ioctl_sync_init()

2026-06-15T12:06:18+00:00

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