From: Joanne Koong <joannelkoong@gmail.com> Introduce the capability to dynamically configure the max pages limit (FUSE_MAX_MAX_PAGES) through a sysctl. This allows system administrators to dynamically set the maximum number of pages that can be used for servicing requests in fuse. Previously, this is gated by FUSE_MAX_MAX_PAGES which is statically set to 256 pages. One result of this is that the buffer size for a write request is limited to 1 MiB on a 4k-page system. The default value for this sysctl is the original limit (256 pages). $ sysctl -a | grep max_pages_limit fs.fuse.max_pages_limit = 256 $ sysctl -n fs.fuse.max_pages_limit 256 $ echo 1024 | sudo tee /proc/sys/fs/fuse/max_pages_limit 1024 $ sysctl -n fs.fuse.max_pages_limit 1024 $ echo 65536 | sudo tee /proc/sys/fs/fuse/max_pages_limit tee: /proc/sys/fs/fuse/max_pages_limit: Invalid argument $ echo 0 | sudo tee /proc/sys/fs/fuse/max_pages_limit tee: /proc/sys/fs/fuse/max_pages_limit: Invalid argument $ echo 65535 | sudo tee /proc/sys/fs/fuse/max_pages_limit 65535 $ sysctl -n fs.fuse.max_pages_limit 65535 Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Conflicts: fs/fuse/Makefile fs/fuse/fuse_i.h fs/fuse/ioctl.c --- Documentation/admin-guide/sysctl/fs.rst | 10 +++++++ fs/fuse/Makefile | 1 + fs/fuse/fuse_i.h | 14 +++++++-- fs/fuse/inode.c | 11 ++++++- fs/fuse/ioctl.c | 2 ++ fs/fuse/sysctl.c | 40 +++++++++++++++++++++++++ 6 files changed, 74 insertions(+), 4 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 a321b84eccaa..297228f9f299 100644 --- a/Documentation/admin-guide/sysctl/fs.rst +++ b/Documentation/admin-guide/sysctl/fs.rst @@ -332,3 +332,13 @@ 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/max_pages_limit`` is a read/write file for +setting/getting the maximum number of pages that can be used for servicing +requests in FUSE. diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile index 0c48b35c058d..184c199e0487 100644 --- a/fs/fuse/Makefile +++ b/fs/fuse/Makefile @@ -9,5 +9,6 @@ obj-$(CONFIG_VIRTIO_FS) += virtiofs.o fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o ioctl.o fuse-$(CONFIG_FUSE_DAX) += dax.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 51e95eac47ff..3f4be114896a 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -36,9 +36,6 @@ /** Default max number of pages that can be used in a single read request */ #define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32 -/** Maximum of max_pages received in init_out */ -#define FUSE_MAX_MAX_PAGES 256 - /** Bias for fi->writectr, meaning new writepages must not be sent */ #define FUSE_NOWRITE INT_MIN @@ -48,6 +45,9 @@ /** Number of dentries for each connection in the control filesystem */ #define FUSE_CTL_NUM_DENTRIES 5 +/** Maximum of max_pages received in init_out */ +extern unsigned int fuse_max_pages_limit; + /** List of active connections */ extern struct list_head fuse_conn_list; @@ -1372,4 +1372,12 @@ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid, void fuse_file_release(struct inode *inode, struct fuse_file *ff, unsigned int open_flags, fl_owner_t id, bool isdir); +#ifdef CONFIG_SYSCTL +extern int fuse_sysctl_register(void); +extern void fuse_sysctl_unregister(void); +#else +#define fuse_sysctl_register() (0) +#define fuse_sysctl_unregister() do { } while (0) +#endif /* CONFIG_SYSCTL */ + #endif /* _FS_FUSE_I_H */ diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 735abf426a06..c83513a02f89 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -35,6 +35,8 @@ DEFINE_MUTEX(fuse_mutex); static int set_global_limit(const char *val, const struct kernel_param *kp); +unsigned int fuse_max_pages_limit = 256; + unsigned max_user_bgreq; module_param_call(max_user_bgreq, set_global_limit, param_get_uint, &max_user_bgreq, 0644); @@ -944,7 +946,7 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); fc->user_ns = get_user_ns(user_ns); fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; - fc->max_pages_limit = FUSE_MAX_MAX_PAGES; + fc->max_pages_limit = fuse_max_pages_limit; INIT_LIST_HEAD(&fc->mounts); list_add(&fm->fc_entry, &fc->mounts); @@ -2014,8 +2016,14 @@ 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: @@ -2026,6 +2034,7 @@ static int __init fuse_fs_init(void) static void fuse_fs_cleanup(void) { + fuse_sysctl_unregister(); unregister_filesystem(&fuse_fs_type); unregister_fuseblk(); diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c index 27115c618e94..33e9558395a3 100644 --- a/fs/fuse/ioctl.c +++ b/fs/fuse/ioctl.c @@ -9,6 +9,8 @@ #include <linux/compat.h> #include <linux/fileattr.h> +#define FUSE_VERITY_ENABLE_ARG_MAX_PAGES 256 + static ssize_t fuse_send_ioctl(struct fuse_mount *fm, struct fuse_args *args, struct fuse_ioctl_out *outarg) { diff --git a/fs/fuse/sysctl.c b/fs/fuse/sysctl.c new file mode 100644 index 000000000000..b272bb333005 --- /dev/null +++ b/fs/fuse/sysctl.c @@ -0,0 +1,40 @@ +// 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; + +/* Bound by fuse_init_out max_pages, which is a u16 */ +static unsigned int sysctl_fuse_max_pages_limit = 65535; + +static struct ctl_table fuse_sysctl_table[] = { + { + .procname = "max_pages_limit", + .data = &fuse_max_pages_limit, + .maxlen = sizeof(fuse_max_pages_limit), + .mode = 0644, + .proc_handler = proc_douintvec_minmax, + .extra1 = SYSCTL_ONE, + .extra2 = &sysctl_fuse_max_pages_limit, + }, +}; + +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; +} -- 2.46.1