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[2a03:2880:25ff:3::face:b00c]) by smtp.gmail.com with ESMTPSA id 00721157ae682-6d2d5daf57bsm6689427b3.117.2024.08.30.09.27.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Aug 2024 09:27:10 -0700 (PDT) From: Joanne Koong 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 Subject: [PATCH v6 1/2] fuse: add optional kernel-enforced timeout for requests Date: Fri, 30 Aug 2024 09:26:48 -0700 Message-ID: <20240830162649.3849586-2-joannelkoong@gmail.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20240830162649.3849586-1-joannelkoong@gmail.com> References: <20240830162649.3849586-1-joannelkoong@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 There are situations where fuse servers can become unresponsive or stuck, for example if the server is in a deadlock. 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) on requests where if the timeout elapses without a reply from the server, the connection will be automatically aborted. Signed-off-by: Joanne Koong --- fs/fuse/dev.c | 26 +++++++++++++++++++++++++- fs/fuse/fuse_i.h | 8 ++++++++ fs/fuse/inode.c | 7 +++++++ 3 files changed, 40 insertions(+), 1 deletion(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 9eb191b5c4de..a4ec817074a2 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -40,6 +40,16 @@ static struct fuse_dev *fuse_get_dev(struct file *file) return READ_ONCE(file->private_data); } +static void fuse_request_timeout(struct timer_list *timer) +{ + struct fuse_req *req = container_of(timer, struct fuse_req, timer); + struct fuse_conn *fc = req->fm->fc; + + req->timer.function = NULL; + + fuse_abort_conn(fc); +} + static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req) { INIT_LIST_HEAD(&req->list); @@ -48,6 +58,8 @@ static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req) refcount_set(&req->count, 1); __set_bit(FR_PENDING, &req->flags); req->fm = fm; + if (fm->fc->req_timeout) + timer_setup(&req->timer, fuse_request_timeout, 0); } static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags) @@ -283,6 +295,9 @@ void fuse_request_end(struct fuse_req *req) struct fuse_conn *fc = fm->fc; struct fuse_iqueue *fiq = &fc->iq; + if (req->timer.function) + timer_delete_sync(&req->timer); + if (test_and_set_bit(FR_FINISHED, &req->flags)) goto put_request; @@ -393,6 +408,8 @@ static void request_wait_answer(struct fuse_req *req) if (test_bit(FR_PENDING, &req->flags)) { list_del(&req->list); spin_unlock(&fiq->lock); + if (req->timer.function) + timer_delete_sync(&req->timer); __fuse_put_request(req); req->out.h.error = -EINTR; return; @@ -409,7 +426,8 @@ static void request_wait_answer(struct fuse_req *req) static void __fuse_request_send(struct fuse_req *req) { - struct fuse_iqueue *fiq = &req->fm->fc->iq; + struct fuse_conn *fc = req->fm->fc; + struct fuse_iqueue *fiq = &fc->iq; BUG_ON(test_bit(FR_BACKGROUND, &req->flags)); spin_lock(&fiq->lock); @@ -421,6 +439,8 @@ static void __fuse_request_send(struct fuse_req *req) /* acquire extra reference, since request is still needed after fuse_request_end() */ __fuse_get_request(req); + if (req->timer.function) + mod_timer(&req->timer, jiffies + fc->req_timeout); queue_request_and_unlock(fiq, req); request_wait_answer(req); @@ -539,6 +559,8 @@ static bool fuse_request_queue_background(struct fuse_req *req) if (fc->num_background == fc->max_background) fc->blocked = 1; list_add_tail(&req->list, &fc->bg_queue); + if (req->timer.function) + mod_timer(&req->timer, jiffies + fc->req_timeout); flush_bg_queue(fc); queued = true; } @@ -594,6 +616,8 @@ static int fuse_simple_notify_reply(struct fuse_mount *fm, spin_lock(&fiq->lock); if (fiq->connected) { + if (req->timer.function) + mod_timer(&req->timer, jiffies + fm->fc->req_timeout); queue_request_and_unlock(fiq, req); } else { err = -ENODEV; diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index f23919610313..97dacafa4289 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -435,6 +435,9 @@ struct fuse_req { /** fuse_mount this request belongs to */ struct fuse_mount *fm; + + /** timer for request replies, if timeout option is enabled */ + struct timer_list timer; }; struct fuse_iqueue; @@ -574,6 +577,8 @@ struct fuse_fs_context { enum fuse_dax_mode dax_mode; unsigned int max_read; unsigned int blksize; + /* Request timeout (in seconds). 0 = no timeout (infinite wait) */ + unsigned int req_timeout; const char *subtype; /* DAX device, may be NULL */ @@ -633,6 +638,9 @@ struct fuse_conn { /** Constrain ->max_pages to this value during feature negotiation */ unsigned int max_pages_limit; + /* Request timeout (in jiffies). 0 = no timeout (infinite wait) */ + unsigned long req_timeout; + /** Input queue */ struct fuse_iqueue iq; diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 99e44ea7d875..9e69006fc026 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -733,6 +733,7 @@ enum { OPT_ALLOW_OTHER, OPT_MAX_READ, OPT_BLKSIZE, + OPT_REQUEST_TIMEOUT, OPT_ERR }; @@ -747,6 +748,7 @@ static const struct fs_parameter_spec fuse_fs_parameters[] = { fsparam_u32 ("max_read", OPT_MAX_READ), fsparam_u32 ("blksize", OPT_BLKSIZE), fsparam_string ("subtype", OPT_SUBTYPE), + fsparam_u32 ("request_timeout", OPT_REQUEST_TIMEOUT), {} }; @@ -830,6 +832,10 @@ static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param) ctx->blksize = result.uint_32; break; + case OPT_REQUEST_TIMEOUT: + ctx->req_timeout = result.uint_32; + break; + default: return -EINVAL; } @@ -1724,6 +1730,7 @@ 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; From patchwork Fri Aug 30 16:26:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13785336 Received: from mail-yw1-f171.google.com (mail-yw1-f171.google.com [209.85.128.171]) (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 5071B1B5ED2 for ; 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[2a03:2880:25ff:74::face:b00c]) by smtp.gmail.com with ESMTPSA id 00721157ae682-6d2d39c73cdsm6673097b3.3.2024.08.30.09.27.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Aug 2024 09:27:12 -0700 (PDT) From: Joanne Koong 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 Subject: [PATCH v6 2/2] fuse: add default_request_timeout and max_request_timeout sysctls Date: Fri, 30 Aug 2024 09:26:49 -0700 Message-ID: <20240830162649.3849586-3-joannelkoong@gmail.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20240830162649.3849586-1-joannelkoong@gmail.com> References: <20240830162649.3849586-1-joannelkoong@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Introduce two new sysctls, "default_request_timeout" and "max_request_timeout". These control how long (in seconds) a server can take to reply to a request. If the server does not reply by the timeout, then the connection will be aborted. "default_request_timeout" sets the default timeout if no timeout is specified by the fuse server on mount. 0 (default) indicates no default timeout should be enforced. If the server did set a timeout, then default_request_timeout will be ignored. "max_request_timeout" sets the upper bound on how long the server may take to reply to a request. 0 (default) indicates no maximum timeout. If the max_request_timeout is set and the fuse server attempts to set a timeout greater than max_request_timeout, the system will default to max_request_timeout. Similarly, if default_request_timeout is greater than max_request_timeout, the system will default to max_request_timeout. If the server does not request a timeout and default_request_timeout is set to 0 but max_request_timeout is set, then the timeout will be max_request_timeout. $ 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 Reviewed-by: Josef Bacik Reviewed-by: Bernd Schubert --- Documentation/admin-guide/sysctl/fs.rst | 31 ++++++++++++++++++ fs/fuse/Makefile | 1 + fs/fuse/fuse_i.h | 16 ++++++++++ fs/fuse/inode.c | 19 ++++++++++- fs/fuse/sysctl.c | 42 +++++++++++++++++++++++++ 5 files changed, 108 insertions(+), 1 deletion(-) 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..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..dabc852a7ff1 100644 --- a/fs/fuse/Makefile +++ b/fs/fuse/Makefile @@ -11,5 +11,6 @@ fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o ioctl.o fuse-y += iomode.o fuse-$(CONFIG_FUSE_DAX) += dax.o fuse-$(CONFIG_FUSE_PASSTHROUGH) += passthrough.o +fuse-$(CONFIG_SYSCTL) += sysctl.o virtiofs-y := virtio_fs.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 + +#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; +}