fuse: add kernel-enforced timeout option for requests

There are situations where fuse servers can become unresponsive or
stuck, for example if the server is deadlocked. Currently, there's no
good wa

fuse: add kernel-enforced timeout option for requests

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 <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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fuse: {io-uring} Fix a possible req cancellation race

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 t

fuse: {io-uring} Fix a possible req cancellation race

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: <[email protected]> # v6.14
Reported-by: Joanne Koong <[email protected]>
Closes: https://lore.kernel.org/all/CAJnrk1ZgHNb78dz-yfNTpxmW7wtT88A=m-zF0ZoLXKLUHRjNTw@mail.gmail.com/
Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Joanne Koong <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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fuse: {io-uring} Make fuse_dev_queue_{interrupt,forget} non-static

These functions are also needed by fuse-over-io-uring.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Luis Henriqu

fuse: {io-uring} Make fuse_dev_queue_{interrupt,forget} non-static

These functions are also needed by fuse-over-io-uring.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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fuse: {io-uring} Make hash-list req unique finding functions non-static

fuse-over-io-uring uses existing functions to find requests based
on their unique id - make these functions non-static.

Signe

fuse: {io-uring} Make hash-list req unique finding functions non-static

fuse-over-io-uring uses existing functions to find requests based
on their unique id - make these functions non-static.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Joanne Koong <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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fuse: Add fuse-io-uring handling into fuse_copy

Add special fuse-io-uring into the fuse argument
copy handler.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Joanne Koong <joannelko

fuse: Add fuse-io-uring handling into fuse_copy

Add special fuse-io-uring into the fuse argument
copy handler.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Joanne Koong <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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fuse: Make fuse_copy non static

Move 'struct fuse_copy_state' and fuse_copy_* functions
to fuse_dev_i.h to make it available for fuse-io-uring.
'copy_out_args()' is renamed to 'fuse_copy_out_args'.

fuse: Make fuse_copy non static

Move 'struct fuse_copy_state' and fuse_copy_* functions
to fuse_dev_i.h to make it available for fuse-io-uring.
'copy_out_args()' is renamed to 'fuse_copy_out_args'.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Joanne Koong <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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fuse: Move request bits

These are needed by fuse-over-io-uring.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Reviewed-by: Joanne Koong <joannelk

fuse: Move request bits

These are needed by fuse-over-io-uring.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Reviewed-by: Joanne Koong <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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fuse: Move fuse_get_dev to header file

Another preparation patch, as this function will be needed by
fuse/dev.c and fuse/dev_uring.c.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by:

fuse: Move fuse_get_dev to header file

Another preparation patch, as this function will be needed by
fuse/dev.c and fuse/dev_uring.c.

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Reviewed-by: Joanne Koong <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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fuse: rename to fuse_dev_end_requests and make non-static

This function is needed by fuse_uring.c to clean ring queues,
so make it non static. Especially in non-static mode the function
name 'end_re

fuse: rename to fuse_dev_end_requests and make non-static

This function is needed by fuse_uring.c to clean ring queues,
so make it non static. Especially in non-static mode the function
name 'end_requests' should be prefixed with fuse_

Signed-off-by: Bernd Schubert <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Reviewed-by: Joanne Koong <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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