[v5,2/2] fuse: add default_request_timeout and max_request_timeout sysctls

Message ID	20240826203234.4079338-3-joannelkoong@gmail.com (mailing list archive)
State	New
Headers	show Received: from mail-yw1-f180.google.com (mail-yw1-f180.google.com [209.85.128.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C64451990C8 for <linux-fsdevel@vger.kernel.org>; Mon, 26 Aug 2024 20:33:13 +0000 (UTC) From: Joanne Koong <joannelkoong@gmail.com> To: miklos@szeredi.hu, linux-fsdevel@vger.kernel.org Cc: josef@toxicpanda.com, bernd.schubert@fastmail.fm, jefflexu@linux.alibaba.com, laoar.shao@gmail.com, kernel-team@meta.com, Bernd Schubert <bschubert@ddn.com> Subject: [PATCH v5 2/2] fuse: add default_request_timeout and max_request_timeout sysctls Date: Mon, 26 Aug 2024 13:32:34 -0700 Message-ID: <20240826203234.4079338-3-joannelkoong@gmail.com> In-Reply-To: <20240826203234.4079338-1-joannelkoong@gmail.com> References: <20240826203234.4079338-1-joannelkoong@gmail.com> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	fuse: add timeout option for requests \| expand [v5,0/2] fuse: add timeout option for requests [v5,1/2] fuse: add optional kernel-enforced timeout for requests [v5,2/2] fuse: add default_request_timeout and max_request_timeout sysctls

diff --git a/Documentation/admin-guide/sysctl/fs.rst b/Documentation/admin-guide/sysctl/fs.rst index 47499a1742bd..3d5a2b5cbba0 100644 --- a/Documentation/admin-guide/sysctl/fs.rst +++ b/Documentation/admin-guide/sysctl/fs.rst @@ -332,3 +332,34 @@ 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. If the server set a timeout, +then default_request_timeout will be ignored. The default +"default_request_timeout" is set to 0. 0 indicates a no-op (eg +requests will not have a default request timeout set if no timeout was +specified by the server). + +``/proc/sys/fs/fuse/max_request_timeout`` is a read/write file for +setting/getting the maximum timeout (in seconds) for a fuse server to +reply to a kernel-issued request. A value greater than 0 automatically opts +the server into a timeout that will be at most "max_request_timeout", even if +the server did not specify a timeout and default_request_timeout is set to 0. +If max_request_timeout is greater than 0 and the server set a timeout greater +than max_request_timeout or default_request_timeout is set to greater than +max_request_timeout, the system will use max_request_timeout as the timeout. +0 indicates a no-op (eg requests will not have an upper bound on the timeout +and if the server did not request a timeout and default_request_timeout was not +set, there will be no timeout). + +Please note that for the timeout options, if the server does not respond to +the request by the time the timeout elapses, then the connection to the fuse +server will be aborted. diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile index 6e0228c6d0cb..cd4ef3e08ebf 100644 --- a/fs/fuse/Makefile +++ b/fs/fuse/Makefile @@ -7,7 +7,7 @@ obj-$(CONFIG_FUSE_FS) += fuse.o obj-$(CONFIG_CUSE) += cuse.o obj-$(CONFIG_VIRTIO_FS) += virtiofs.o -fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o ioctl.o +fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o ioctl.o sysctl.o fuse-y += iomode.o fuse-$(CONFIG_FUSE_DAX) += dax.o fuse-$(CONFIG_FUSE_PASSTHROUGH) += passthrough.o diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 97dacafa4289..04daf366735d 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -47,6 +47,14 @@ /** Number of dentries for each connection in the control filesystem */ #define FUSE_CTL_NUM_DENTRIES 5 +/* + * Default timeout (in seconds) for the server to reply to a request + * if no timeout was specified on mount + */ +extern u32 fuse_default_req_timeout; +/** Max timeout (in seconds) for the server to reply to a request */ +extern u32 fuse_max_req_timeout; + /** List of active connections */ extern struct list_head fuse_conn_list; @@ -1480,4 +1488,12 @@ ssize_t fuse_passthrough_splice_write(struct pipe_inode_info *pipe, size_t len, unsigned int flags); ssize_t fuse_passthrough_mmap(struct file *file, struct vm_area_struct *vma); +#ifdef CONFIG_SYSCTL +int fuse_sysctl_register(void); +void fuse_sysctl_unregister(void); +#else +static inline int fuse_sysctl_register(void) { return 0; } +static inline void fuse_sysctl_unregister(void) { return; } +#endif /* CONFIG_SYSCTL */ + #endif /* _FS_FUSE_I_H */ diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 9e69006fc026..cf333448f2d3 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -35,6 +35,10 @@ DEFINE_MUTEX(fuse_mutex); static int set_global_limit(const char *val, const struct kernel_param *kp); +/* default is no timeout */ +u32 fuse_default_req_timeout = 0; +u32 fuse_max_req_timeout = 0; + unsigned max_user_bgreq; module_param_call(max_user_bgreq, set_global_limit, param_get_uint, &max_user_bgreq, 0644); @@ -1678,6 +1682,7 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) struct fuse_conn *fc = fm->fc; struct inode *root; struct dentry *root_dentry; + u32 req_timeout; int err; err = -EINVAL; @@ -1730,10 +1735,16 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) fc->group_id = ctx->group_id; fc->legacy_opts_show = ctx->legacy_opts_show; fc->max_read = max_t(unsigned int, 4096, ctx->max_read); - fc->req_timeout = ctx->req_timeout * HZ; fc->destroy = ctx->destroy; fc->no_control = ctx->no_control; fc->no_force_umount = ctx->no_force_umount; + req_timeout = ctx->req_timeout ?: fuse_default_req_timeout; + if (!fuse_max_req_timeout) + fc->req_timeout = req_timeout * HZ; + else if (!req_timeout) + fc->req_timeout = fuse_max_req_timeout * HZ; + else + fc->req_timeout = min(req_timeout, fuse_max_req_timeout) * HZ; err = -ENOMEM; root = fuse_get_root_inode(sb, ctx->rootmode); @@ -2046,8 +2057,14 @@ static int __init fuse_fs_init(void) if (err) goto out3; + err = fuse_sysctl_register(); + if (err) + goto out4; + return 0; + out4: + unregister_filesystem(&fuse_fs_type); out3: unregister_fuseblk(); out2: diff --git a/fs/fuse/sysctl.c b/fs/fuse/sysctl.c new file mode 100644 index 000000000000..c87bb0ecbfa9 --- /dev/null +++ b/fs/fuse/sysctl.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +/* +* linux/fs/fuse/fuse_sysctl.c +* +* Sysctl interface to fuse parameters +*/ +#include <linux/sysctl.h> + +#include "fuse_i.h" + +static struct ctl_table_header *fuse_table_header; + +static struct ctl_table fuse_sysctl_table[] = { + { + .procname = "default_request_timeout", + .data = &fuse_default_req_timeout, + .maxlen = sizeof(fuse_default_req_timeout), + .mode = 0644, + .proc_handler = proc_douintvec, + }, + { + .procname = "max_request_timeout", + .data = &fuse_max_req_timeout, + .maxlen = sizeof(fuse_max_req_timeout), + .mode = 0644, + .proc_handler = proc_douintvec, + }, +}; + +int fuse_sysctl_register(void) +{ + fuse_table_header = register_sysctl("fs/fuse", fuse_sysctl_table); + if (!fuse_table_header) + return -ENOMEM; + return 0; +} + +void fuse_sysctl_unregister(void) +{ + unregister_sysctl_table(fuse_table_header); + fuse_table_header = NULL; +}

[v5,2/2] fuse: add default_request_timeout and max_request_timeout sysctls

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