On Wed, Aug 21, 2024 at 2:31 AM Joanne Koong <joannelkoong@xxxxxxxxx> wrote: > > On Mon, Aug 19, 2024 at 11:40 PM Yafang Shao <laoar.shao@xxxxxxxxx> wrote: > > > > On Wed, Aug 14, 2024 at 7:24 AM Joanne Koong <joannelkoong@xxxxxxxxx> wrote: > > > > > > Introduce two new sysctls, "default_request_timeout" and > > > "max_request_timeout". These control timeouts on replies by the > > > server to kernel-issued fuse requests. > > > > > > "default_request_timeout" sets a timeout if no timeout is specified by > > > the fuse server on mount. 0 (default) indicates no timeout should be enforced. > > > > > > "max_request_timeout" sets a maximum timeout for fuse requests. If the > > > fuse server attempts to set a timeout greater than max_request_timeout, > > > the system will default to max_request_timeout. Similarly, if the max > > > default timeout is greater than the max request timeout, the system will > > > default to the max request timeout. 0 (default) indicates no timeout should > > > be enforced. > > > > > > $ sysctl -a | grep fuse > > > fs.fuse.default_request_timeout = 0 > > > fs.fuse.max_request_timeout = 0 > > > > > > $ echo 0x100000000 | sudo tee /proc/sys/fs/fuse/default_request_timeout > > > tee: /proc/sys/fs/fuse/default_request_timeout: Invalid argument > > > > > > $ echo 0xFFFFFFFF | sudo tee /proc/sys/fs/fuse/default_request_timeout > > > 0xFFFFFFFF > > > > > > $ sysctl -a | grep fuse > > > fs.fuse.default_request_timeout = 4294967295 > > > fs.fuse.max_request_timeout = 0 > > > > > > Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx> > > > Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> > > > Reviewed-by: Bernd Schubert <bschubert@xxxxxxx> > > > --- > > > Documentation/admin-guide/sysctl/fs.rst | 17 ++++++++++ > > > fs/fuse/Makefile | 2 +- > > > fs/fuse/fuse_i.h | 16 ++++++++++ > > > fs/fuse/inode.c | 19 ++++++++++- > > > fs/fuse/sysctl.c | 42 +++++++++++++++++++++++++ > > > 5 files changed, 94 insertions(+), 2 deletions(-) > > > create mode 100644 fs/fuse/sysctl.c > > > > > > diff --git a/Documentation/admin-guide/sysctl/fs.rst b/Documentation/admin-guide/sysctl/fs.rst > > > index 47499a1742bd..44fd495f69b4 100644 > > > --- a/Documentation/admin-guide/sysctl/fs.rst > > > +++ b/Documentation/admin-guide/sysctl/fs.rst > > > @@ -332,3 +332,20 @@ Each "watch" costs roughly 90 bytes on a 32-bit kernel, and roughly 160 bytes > > > on a 64-bit one. > > > The current default value for ``max_user_watches`` is 4% of the > > > available low memory, divided by the "watch" cost in bytes. > > > + > > > +5. /proc/sys/fs/fuse - Configuration options for FUSE filesystems > > > +===================================================================== > > > + > > > +This directory contains the following configuration options for FUSE > > > +filesystems: > > > + > > > +``/proc/sys/fs/fuse/default_request_timeout`` is a read/write file for > > > +setting/getting the default timeout (in seconds) for a fuse server to > > > +reply to a kernel-issued request in the event where the server did not > > > +specify a timeout at mount. 0 indicates no timeout. > > > > While testing on my servers, I observed that the timeout value appears > > to be doubled. For instance, if I set the timeout to 10 seconds, the > > "Timer expired" message occurs after 20 seconds. > > > > Is this an expected behavior, or is the doubling unavoidable? I'm okay > > with it as long as we have a functioning timeout. However, I recommend > > documenting this behavior to avoid any potential confusion for users. > > Hi Yafang, > > Are you testing this by running "cat hello" from the libfuse hello > example server and seeing the doubled timeout? right. > > This is happening because cat hello sends two FUSE_READ requests. The > first FUSE_READ is a background request (called from > fuse_readahead()). I confirmed that this takes 10 seconds to time out > and then the timeout handler kicks in. Then the second FUSE_READ is a > regular request (called from fuse_read_folio() -> fuse_do_readpage()). > This second request also takes 10 seconds to time out. After this > second request times out is when the "cat hello" returns, which is why > the overall time is 20 seconds because of the 2 requests each taking > 10 seconds. > Thanks for your detailed explanation. -- Regards Yafang
