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path: root/fs/fuse/dev_uring_i.h
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2025-03-31fuse: add kernel-enforced timeout option for requestsJoanne Koong
There are situations where fuse servers can become unresponsive or stuck, for example if the server is deadlocked. Currently, there's no good way to detect if a server is stuck and needs to be killed manually. This commit adds an option for enforcing a timeout (in seconds) for requests where if the timeout elapses without the server responding to the request, the connection will be automatically aborted. Please note that these timeouts are not 100% precise. For example, the request may take roughly an extra FUSE_TIMEOUT_TIMER_FREQ seconds beyond the requested timeout due to internal implementation, in order to mitigate overhead. [SzM: Bump the API version number] Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-03-31fuse: removed unused function fuse_uring_create() from headerLuis Henriques
Function fuse_uring_create() is used only from dev_uring.c and does not need to be exposed in the header file. Furthermore, it has the wrong signature. While there, also remove the 'struct fuse_ring' forward declaration. Signed-off-by: Luis Henriques <luis@igalia.com> Reviewed-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-03-31fuse: {io-uring} Fix a possible req cancellation raceBernd Schubert
task-A (application) might be in request_wait_answer and try to remove the request when it has FR_PENDING set. task-B (a fuse-server io-uring task) might handle this request with FUSE_IO_URING_CMD_COMMIT_AND_FETCH, when fetching the next request and accessed the req from the pending list in fuse_uring_ent_assign_req(). That code path was not protected by fiq->lock and so might race with task-A. For scaling reasons we better don't use fiq->lock, but add a handler to remove canceled requests from the queue. This also removes usage of fiq->lock from fuse_uring_add_req_to_ring_ent() altogether, as it was there just to protect against this race and incomplete. Also added is a comment why FR_PENDING is not cleared. Fixes: c090c8abae4b ("fuse: Add io-uring sqe commit and fetch support") Cc: <stable@vger.kernel.org> # v6.14 Reported-by: Joanne Koong <joannelkoong@gmail.com> Closes: https://lore.kernel.org/all/CAJnrk1ZgHNb78dz-yfNTpxmW7wtT88A=m-zF0ZoLXKLUHRjNTw@mail.gmail.com/ Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-27fuse: {io-uring} Prevent mount point hang on fuse-server terminationBernd Schubert
When the fuse-server terminates while the fuse-client or kernel still has queued URING_CMDs, these commands retain references to the struct file used by the fuse connection. This prevents fuse_dev_release() from being invoked, resulting in a hung mount point. This patch addresses the issue by making queued URING_CMDs cancelable, allowing fuse_dev_release() to proceed as expected and preventing the mount point from hanging. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-27fuse: Allow to queue bg requests through io-uringBernd Schubert
This prepares queueing and sending background requests through io-uring. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-27fuse: Allow to queue fg requests through io-uringBernd Schubert
This prepares queueing and sending foreground requests through io-uring. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-27fuse: {io-uring} Handle teardown of ring entriesBernd Schubert
On teardown struct file_operations::uring_cmd requests need to be completed by calling io_uring_cmd_done(). Not completing all ring entries would result in busy io-uring tasks giving warning messages in intervals and unreleased struct file. Additionally the fuse connection and with that the ring can only get released when all io-uring commands are completed. Completion is done with ring entries that are a) in waiting state for new fuse requests - io_uring_cmd_done is needed b) already in userspace - io_uring_cmd_done through teardown is not needed, the request can just get released. If fuse server is still active and commits such a ring entry, fuse_uring_cmd() already checks if the connection is active and then complete the io-uring itself with -ENOTCONN. I.e. special handling is not needed. This scheme is basically represented by the ring entry state FRRS_WAIT and FRRS_USERSPACE. Entries in state: - FRRS_INIT: No action needed, do not contribute to ring->queue_refs yet - All other states: Are currently processed by other tasks, async teardown is needed and it has to wait for the two states above. It could be also solved without an async teardown task, but would require additional if conditions in hot code paths. Also in my personal opinion the code looks cleaner with async teardown. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-27fuse: Add io-uring sqe commit and fetch supportBernd Schubert
This adds support for fuse request completion through ring SQEs (FUSE_URING_CMD_COMMIT_AND_FETCH handling). After committing the ring entry it becomes available for new fuse requests. Handling of requests through the ring (SQE/CQE handling) is complete now. Fuse request data are copied through the mmaped ring buffer, there is no support for any zero copy yet. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-24fuse: {io-uring} Handle SQEs - register commandsBernd Schubert
This adds basic support for ring SQEs (with opcode=IORING_OP_URING_CMD). For now only FUSE_IO_URING_CMD_REGISTER is handled to register queue entries. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>