mirror_zfs/module/os/linux/zfs/zfs_ioctl_os.c
Prakash Surya 13312e2fa1
Reduce need for contiguous memory for ioctls
We've had cases where we trigger an OOM despite having memory freely
available on the system. For example, here, we had about 21GB free:

    kernel: Node 0 Normal: 2418758*4kB (UME) 1549533*8kB (UE) 0*16kB
    0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB =
    22071296kB

The problem being, all the memory is in 4K and 8K contiguous regions,
but the allocation request was for a 16K contiguous region:

    kernel: SafeExecutors-4 invoked oom-killer:
    gfp_mask=0x42dc0(GFP_KERNEL|__GFP_NOWARN|__GFP_COMP|__GFP_ZERO),
    order=2, oom_score_adj=0

The offending allocation came from this call trace:

    kernel: Call Trace:
    kernel:  dump_stack+0x57/0x7a
    kernel:  dump_header+0x4f/0x1e1
    kernel:  oom_kill_process.cold.33+0xb/0x10
    kernel:  out_of_memory+0x1ad/0x490
    kernel:  __alloc_pages_slowpath+0xd55/0xe40
    kernel:  __alloc_pages_nodemask+0x2df/0x330
    kernel:  kmalloc_large_node+0x42/0x90
    kernel:  __kmalloc_node+0x25a/0x320
    kernel:  ? spl_kmem_free_impl+0x21/0x30 [spl]
    kernel:  spl_kmem_alloc_impl+0xa5/0x100 [spl]
    kernel:  spl_kmem_zalloc+0x19/0x20 [spl]
    kernel:  zfsdev_ioctl+0x2b/0xe0 [zfs]
    kernel:  do_vfs_ioctl+0xa9/0x640
    kernel:  ? __audit_syscall_entry+0xdd/0x130
    kernel:  ksys_ioctl+0x67/0x90
    kernel:  __x64_sys_ioctl+0x1a/0x20
    kernel:  do_syscall_64+0x5e/0x200
    kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xa9
    kernel: RIP: 0033:0x7fdca3674317

The problem is, for each ioctl that ZFS makes, it has to allocate a
zfs_cmd_t structure, which is 13744 bytes in size (on my system):

    sdb> sizeof zfs_cmd
    (size_t)13744

This size, coupled with the fact that we currently allocate it with
kmem_zalloc, means we need a 16K contiguous region of memory to satisfy
the request.

The solution taken by this change, is to use "vmem" instead of "kmem" to
do the allocation, such that we don't necessarily need a contiguous 16K
memory region to satisfy the allocation.

Arguably, a better solution would be not to require such a large
allocation to begin with (e.g. reduce the size of the zfs_cmd_t
structure), but that'd be a much larger change than this "one liner".
Thus, I've opted for this approach for now; we can always circle back
and attempt to reduce the size of the structure in the future.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Don Brady <don.brady@delphix.com>
Signed-off-by: Prakash Surya <prakash.surya@delphix.com>
Closes #14474
2023-02-13 16:35:59 -08:00

376 lines
8.4 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or https://opensource.org/licenses/CDDL-1.0.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Portions Copyright 2011 Martin Matuska
* Copyright 2015, OmniTI Computer Consulting, Inc. All rights reserved.
* Portions Copyright 2012 Pawel Jakub Dawidek <pawel@dawidek.net>
* Copyright (c) 2014, 2016 Joyent, Inc. All rights reserved.
* Copyright 2016 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2014, Joyent, Inc. All rights reserved.
* Copyright (c) 2011, 2018 by Delphix. All rights reserved.
* Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
* Copyright (c) 2013 Steven Hartland. All rights reserved.
* Copyright (c) 2014 Integros [integros.com]
* Copyright 2016 Toomas Soome <tsoome@me.com>
* Copyright (c) 2016 Actifio, Inc. All rights reserved.
* Copyright (c) 2018, loli10K <ezomori.nozomu@gmail.com>. All rights reserved.
* Copyright 2017 RackTop Systems.
* Copyright (c) 2017 Open-E, Inc. All Rights Reserved.
* Copyright (c) 2019 Datto Inc.
* Copyright (c) 2021 Klara, Inc.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/uio.h>
#include <sys/file.h>
#include <sys/kmem.h>
#include <sys/stat.h>
#include <sys/zfs_ioctl.h>
#include <sys/zfs_vfsops.h>
#include <sys/zap.h>
#include <sys/spa.h>
#include <sys/nvpair.h>
#include <sys/fs/zfs.h>
#include <sys/zfs_ctldir.h>
#include <sys/zfs_dir.h>
#include <sys/zfs_onexit.h>
#include <sys/zvol.h>
#include <sys/fm/util.h>
#include <sys/dsl_crypt.h>
#include <sys/crypto/icp.h>
#include <sys/zstd/zstd.h>
#include <sys/zfs_ioctl_impl.h>
#include <sys/zfs_sysfs.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
boolean_t
zfs_vfs_held(zfsvfs_t *zfsvfs)
{
return (zfsvfs->z_sb != NULL);
}
int
zfs_vfs_ref(zfsvfs_t **zfvp)
{
if (*zfvp == NULL || (*zfvp)->z_sb == NULL ||
!atomic_inc_not_zero(&((*zfvp)->z_sb->s_active))) {
return (SET_ERROR(ESRCH));
}
return (0);
}
void
zfs_vfs_rele(zfsvfs_t *zfsvfs)
{
deactivate_super(zfsvfs->z_sb);
}
void
zfsdev_private_set_state(void *priv, zfsdev_state_t *zs)
{
struct file *filp = priv;
filp->private_data = zs;
}
zfsdev_state_t *
zfsdev_private_get_state(void *priv)
{
struct file *filp = priv;
return (filp->private_data);
}
static int
zfsdev_open(struct inode *ino, struct file *filp)
{
int error;
mutex_enter(&zfsdev_state_lock);
error = zfsdev_state_init(filp);
mutex_exit(&zfsdev_state_lock);
return (-error);
}
static int
zfsdev_release(struct inode *ino, struct file *filp)
{
zfsdev_state_destroy(filp);
return (0);
}
static long
zfsdev_ioctl(struct file *filp, unsigned cmd, unsigned long arg)
{
uint_t vecnum;
zfs_cmd_t *zc;
int error, rc;
vecnum = cmd - ZFS_IOC_FIRST;
zc = vmem_zalloc(sizeof (zfs_cmd_t), KM_SLEEP);
if (ddi_copyin((void *)(uintptr_t)arg, zc, sizeof (zfs_cmd_t), 0)) {
error = -SET_ERROR(EFAULT);
goto out;
}
error = -zfsdev_ioctl_common(vecnum, zc, 0);
rc = ddi_copyout(zc, (void *)(uintptr_t)arg, sizeof (zfs_cmd_t), 0);
if (error == 0 && rc != 0)
error = -SET_ERROR(EFAULT);
out:
vmem_free(zc, sizeof (zfs_cmd_t));
return (error);
}
static int
zfs_ioc_userns_attach(zfs_cmd_t *zc)
{
int error;
if (zc == NULL)
return (SET_ERROR(EINVAL));
error = zone_dataset_attach(CRED(), zc->zc_name, zc->zc_cleanup_fd);
/*
* Translate ENOTTY to ZFS_ERR_NOT_USER_NAMESPACE as we just arrived
* back from the SPL layer, which does not know about ZFS_ERR_* errors.
* See the comment at the user_ns_get() function in spl-zone.c for
* details.
*/
if (error == ENOTTY)
error = ZFS_ERR_NOT_USER_NAMESPACE;
return (error);
}
static int
zfs_ioc_userns_detach(zfs_cmd_t *zc)
{
int error;
if (zc == NULL)
return (SET_ERROR(EINVAL));
error = zone_dataset_detach(CRED(), zc->zc_name, zc->zc_cleanup_fd);
/*
* See the comment in zfs_ioc_userns_attach() for details on what is
* going on here.
*/
if (error == ENOTTY)
error = ZFS_ERR_NOT_USER_NAMESPACE;
return (error);
}
uint64_t
zfs_max_nvlist_src_size_os(void)
{
if (zfs_max_nvlist_src_size != 0)
return (zfs_max_nvlist_src_size);
return (MIN(ptob(zfs_totalram_pages) / 4, 128 * 1024 * 1024));
}
/* Update the VFS's cache of mountpoint properties */
void
zfs_ioctl_update_mount_cache(const char *dsname)
{
}
void
zfs_ioctl_init_os(void)
{
zfs_ioctl_register_dataset_nolog(ZFS_IOC_USERNS_ATTACH,
zfs_ioc_userns_attach, zfs_secpolicy_config, POOL_CHECK_NONE);
zfs_ioctl_register_dataset_nolog(ZFS_IOC_USERNS_DETACH,
zfs_ioc_userns_detach, zfs_secpolicy_config, POOL_CHECK_NONE);
}
#ifdef CONFIG_COMPAT
static long
zfsdev_compat_ioctl(struct file *filp, unsigned cmd, unsigned long arg)
{
return (zfsdev_ioctl(filp, cmd, arg));
}
#else
#define zfsdev_compat_ioctl NULL
#endif
static const struct file_operations zfsdev_fops = {
.open = zfsdev_open,
.release = zfsdev_release,
.unlocked_ioctl = zfsdev_ioctl,
.compat_ioctl = zfsdev_compat_ioctl,
.owner = THIS_MODULE,
};
static struct miscdevice zfs_misc = {
.minor = ZFS_DEVICE_MINOR,
.name = ZFS_DRIVER,
.fops = &zfsdev_fops,
};
MODULE_ALIAS_MISCDEV(ZFS_DEVICE_MINOR);
MODULE_ALIAS("devname:zfs");
int
zfsdev_attach(void)
{
int error;
error = misc_register(&zfs_misc);
if (error == -EBUSY) {
/*
* Fallback to dynamic minor allocation in the event of a
* collision with a reserved minor in linux/miscdevice.h.
* In this case the kernel modules must be manually loaded.
*/
printk(KERN_INFO "ZFS: misc_register() with static minor %d "
"failed %d, retrying with MISC_DYNAMIC_MINOR\n",
ZFS_DEVICE_MINOR, error);
zfs_misc.minor = MISC_DYNAMIC_MINOR;
error = misc_register(&zfs_misc);
}
if (error)
printk(KERN_INFO "ZFS: misc_register() failed %d\n", error);
return (error);
}
void
zfsdev_detach(void)
{
misc_deregister(&zfs_misc);
}
#ifdef ZFS_DEBUG
#define ZFS_DEBUG_STR " (DEBUG mode)"
#else
#define ZFS_DEBUG_STR ""
#endif
static int
openzfs_init_os(void)
{
int error;
if ((error = zfs_kmod_init()) != 0) {
printk(KERN_NOTICE "ZFS: Failed to Load ZFS Filesystem v%s-%s%s"
", rc = %d\n", ZFS_META_VERSION, ZFS_META_RELEASE,
ZFS_DEBUG_STR, error);
return (-error);
}
zfs_sysfs_init();
printk(KERN_NOTICE "ZFS: Loaded module v%s-%s%s, "
"ZFS pool version %s, ZFS filesystem version %s\n",
ZFS_META_VERSION, ZFS_META_RELEASE, ZFS_DEBUG_STR,
SPA_VERSION_STRING, ZPL_VERSION_STRING);
#ifndef CONFIG_FS_POSIX_ACL
printk(KERN_NOTICE "ZFS: Posix ACLs disabled by kernel\n");
#endif /* CONFIG_FS_POSIX_ACL */
return (0);
}
static void
openzfs_fini_os(void)
{
zfs_sysfs_fini();
zfs_kmod_fini();
printk(KERN_NOTICE "ZFS: Unloaded module v%s-%s%s\n",
ZFS_META_VERSION, ZFS_META_RELEASE, ZFS_DEBUG_STR);
}
extern int __init zcommon_init(void);
extern void zcommon_fini(void);
static int __init
openzfs_init(void)
{
int err;
if ((err = zcommon_init()) != 0)
goto zcommon_failed;
if ((err = icp_init()) != 0)
goto icp_failed;
if ((err = zstd_init()) != 0)
goto zstd_failed;
if ((err = openzfs_init_os()) != 0)
goto openzfs_os_failed;
return (0);
openzfs_os_failed:
zstd_fini();
zstd_failed:
icp_fini();
icp_failed:
zcommon_fini();
zcommon_failed:
return (err);
}
static void __exit
openzfs_fini(void)
{
openzfs_fini_os();
zstd_fini();
icp_fini();
zcommon_fini();
}
#if defined(_KERNEL)
module_init(openzfs_init);
module_exit(openzfs_fini);
#endif
MODULE_ALIAS("zavl");
MODULE_ALIAS("icp");
MODULE_ALIAS("zlua");
MODULE_ALIAS("znvpair");
MODULE_ALIAS("zunicode");
MODULE_ALIAS("zcommon");
MODULE_ALIAS("zzstd");
MODULE_DESCRIPTION("ZFS");
MODULE_AUTHOR(ZFS_META_AUTHOR);
MODULE_LICENSE("Dual MIT/GPL"); /* lua */
MODULE_LICENSE("Dual BSD/GPL"); /* zstd / misc */
MODULE_LICENSE(ZFS_META_LICENSE);
MODULE_VERSION(ZFS_META_VERSION "-" ZFS_META_RELEASE);