freebsd-dev/include/sys/zfs_ioctl_impl.h
Richard Yao ab8d9c1783 Cleanup: 64-bit kernel module parameters should use fixed width types
Various module parameters such as `zfs_arc_max` were originally
`uint64_t` on OpenSolaris/Illumos, but were changed to `unsigned long`
for Linux compatibility because Linux's kernel default module parameter
implementation did not support 64-bit types on 32-bit platforms. This
caused problems when porting OpenZFS to Windows because its LLP64 memory
model made `unsigned long` a 32-bit type on 64-bit, which created the
undesireable situation that parameters that should accept 64-bit values
could not on 64-bit Windows.

Upon inspection, it turns out that the Linux kernel module parameter
interface is extensible, such that we are allowed to define our own
types. Rather than maintaining the original type change via hacks to to
continue shrinking module parameters on 32-bit Linux, we implement
support for 64-bit module parameters on Linux.

After doing a review of all 64-bit kernel parameters (found via the man
page and also proposed changes by Andrew Innes), the kernel module
parameters fell into a few groups:

Parameters that were originally 64-bit on Illumos:

 * dbuf_cache_max_bytes
 * dbuf_metadata_cache_max_bytes
 * l2arc_feed_min_ms
 * l2arc_feed_secs
 * l2arc_headroom
 * l2arc_headroom_boost
 * l2arc_write_boost
 * l2arc_write_max
 * metaslab_aliquot
 * metaslab_force_ganging
 * zfetch_array_rd_sz
 * zfs_arc_max
 * zfs_arc_meta_limit
 * zfs_arc_meta_min
 * zfs_arc_min
 * zfs_async_block_max_blocks
 * zfs_condense_max_obsolete_bytes
 * zfs_condense_min_mapping_bytes
 * zfs_deadman_checktime_ms
 * zfs_deadman_synctime_ms
 * zfs_initialize_chunk_size
 * zfs_initialize_value
 * zfs_lua_max_instrlimit
 * zfs_lua_max_memlimit
 * zil_slog_bulk

Parameters that were originally 32-bit on Illumos:

 * zfs_per_txg_dirty_frees_percent

Parameters that were originally `ssize_t` on Illumos:

 * zfs_immediate_write_sz

Note that `ssize_t` is `int32_t` on 32-bit and `int64_t` on 64-bit. It
has been upgraded to 64-bit.

Parameters that were `long`/`unsigned long` because of Linux/FreeBSD
influence:

 * l2arc_rebuild_blocks_min_l2size
 * zfs_key_max_salt_uses
 * zfs_max_log_walking
 * zfs_max_logsm_summary_length
 * zfs_metaslab_max_size_cache_sec
 * zfs_min_metaslabs_to_flush
 * zfs_multihost_interval
 * zfs_unflushed_log_block_max
 * zfs_unflushed_log_block_min
 * zfs_unflushed_log_block_pct
 * zfs_unflushed_max_mem_amt
 * zfs_unflushed_max_mem_ppm

New parameters that do not exist in Illumos:

 * l2arc_trim_ahead
 * vdev_file_logical_ashift
 * vdev_file_physical_ashift
 * zfs_arc_dnode_limit
 * zfs_arc_dnode_limit_percent
 * zfs_arc_dnode_reduce_percent
 * zfs_arc_meta_limit_percent
 * zfs_arc_sys_free
 * zfs_deadman_ziotime_ms
 * zfs_delete_blocks
 * zfs_history_output_max
 * zfs_livelist_max_entries
 * zfs_max_async_dedup_frees
 * zfs_max_nvlist_src_size
 * zfs_rebuild_max_segment
 * zfs_rebuild_vdev_limit
 * zfs_unflushed_log_txg_max
 * zfs_vdev_max_auto_ashift
 * zfs_vdev_min_auto_ashift
 * zfs_vnops_read_chunk_size
 * zvol_max_discard_blocks

Rather than clutter the lists with commentary, the module parameters
that need comments are repeated below.

A few parameters were defined in Linux/FreeBSD specific code, where the
use of ulong/long is not an issue for portability, so we leave them
alone:

 * zfs_delete_blocks
 * zfs_key_max_salt_uses
 * zvol_max_discard_blocks

The documentation for a few parameters was found to be incorrect:

 * zfs_deadman_checktime_ms - incorrectly documented as int
 * zfs_delete_blocks - not documented as Linux only
 * zfs_history_output_max - incorrectly documented as int
 * zfs_vnops_read_chunk_size - incorrectly documented as long
 * zvol_max_discard_blocks - incorrectly documented as ulong

The documentation for these has been fixed, alongside the changes to
document the switch to fixed width types.

In addition, several kernel module parameters were percentages or held
ashift values, so being 64-bit never made sense for them. They have been
downgraded to 32-bit:

 * vdev_file_logical_ashift
 * vdev_file_physical_ashift
 * zfs_arc_dnode_limit_percent
 * zfs_arc_dnode_reduce_percent
 * zfs_arc_meta_limit_percent
 * zfs_per_txg_dirty_frees_percent
 * zfs_unflushed_log_block_pct
 * zfs_vdev_max_auto_ashift
 * zfs_vdev_min_auto_ashift

Of special note are `zfs_vdev_max_auto_ashift` and
`zfs_vdev_min_auto_ashift`, which were already defined as `uint64_t`,
and passed to the kernel as `ulong`. This is inherently buggy on big
endian 32-bit Linux, since the values would not be written to the
correct locations. 32-bit FreeBSD was unaffected because its sysctl code
correctly treated this as a `uint64_t`.

Lastly, a code comment suggests that `zfs_arc_sys_free` is
Linux-specific, but there is nothing to indicate to me that it is
Linux-specific. Nothing was done about that.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Original-patch-by: Andrew Innes <andrew.c12@gmail.com>
Original-patch-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #13984
Closes #14004
2022-10-13 10:03:29 -07:00

102 lines
3.3 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
*/
#ifndef _ZFS_IOCTL_IMPL_H_
#define _ZFS_IOCTL_IMPL_H_
extern kmutex_t zfsdev_state_lock;
extern uint64_t zfs_max_nvlist_src_size;
typedef int zfs_ioc_legacy_func_t(zfs_cmd_t *);
typedef int zfs_ioc_func_t(const char *, nvlist_t *, nvlist_t *);
typedef int zfs_secpolicy_func_t(zfs_cmd_t *, nvlist_t *, cred_t *);
typedef enum {
POOL_CHECK_NONE = 1 << 0,
POOL_CHECK_SUSPENDED = 1 << 1,
POOL_CHECK_READONLY = 1 << 2,
} zfs_ioc_poolcheck_t;
typedef enum {
NO_NAME,
POOL_NAME,
DATASET_NAME,
ENTITY_NAME
} zfs_ioc_namecheck_t;
/*
* IOC Keys are used to document and validate user->kernel interface inputs.
* See zfs_keys_recv_new for an example declaration. Any key name that is not
* listed will be rejected as input.
*
* The keyname 'optional' is always allowed, and must be an nvlist if present.
* Arguments which older kernels can safely ignore can be placed under the
* "optional" key.
*
* When adding new keys to an existing ioc for new functionality, consider:
* - adding an entry into zfs_sysfs.c zfs_features[] list
* - updating the libzfs_input_check.c test utility
*
* Note: in the ZK_WILDCARDLIST case, the name serves as documentation
* for the expected name (bookmark, snapshot, property, etc) but there
* is no validation in the preflight zfs_check_input_nvpairs() check.
*/
typedef enum {
ZK_OPTIONAL = 1 << 0, /* pair is optional */
ZK_WILDCARDLIST = 1 << 1, /* one or more unspecified key names */
} ioc_key_flag_t;
typedef struct zfs_ioc_key {
const char *zkey_name;
data_type_t zkey_type;
ioc_key_flag_t zkey_flags;
} zfs_ioc_key_t;
int zfs_secpolicy_config(zfs_cmd_t *, nvlist_t *, cred_t *);
void zfs_ioctl_register_dataset_nolog(zfs_ioc_t, zfs_ioc_legacy_func_t *,
zfs_secpolicy_func_t *, zfs_ioc_poolcheck_t);
void zfs_ioctl_register(const char *, zfs_ioc_t, zfs_ioc_func_t *,
zfs_secpolicy_func_t *, zfs_ioc_namecheck_t, zfs_ioc_poolcheck_t,
boolean_t, boolean_t, const zfs_ioc_key_t *, size_t);
uint64_t zfs_max_nvlist_src_size_os(void);
void zfs_ioctl_update_mount_cache(const char *dsname);
void zfs_ioctl_init_os(void);
boolean_t zfs_vfs_held(zfsvfs_t *);
int zfs_vfs_ref(zfsvfs_t **);
void zfs_vfs_rele(zfsvfs_t *);
long zfsdev_ioctl_common(uint_t, zfs_cmd_t *, int);
int zfsdev_attach(void);
void zfsdev_detach(void);
void zfsdev_private_set_state(void *, zfsdev_state_t *);
zfsdev_state_t *zfsdev_private_get_state(void *);
int zfsdev_state_init(void *);
void zfsdev_state_destroy(void *);
int zfs_kmod_init(void);
void zfs_kmod_fini(void);
#endif