mirror_zfs/module/zcommon/zprop_common.c
Richard Yao b8d06fca08 Switch KM_SLEEP to KM_PUSHPAGE
Differences between how paging is done on Solaris and Linux can cause
deadlocks if KM_SLEEP is used in any the following contexts.

  * The txg_sync thread
  * The zvol write/discard threads
  * The zpl_putpage() VFS callback

This is because KM_SLEEP will allow for direct reclaim which may result
in the VM calling back in to the filesystem or block layer to write out
pages.  If a lock is held over this operation the potential exists to
deadlock the system.  To ensure forward progress all memory allocations
in these contexts must us KM_PUSHPAGE which disables performing any I/O
to accomplish the memory allocation.

Previously, this behavior was acheived by setting PF_MEMALLOC on the
thread.  However, that resulted in unexpected side effects such as the
exhaustion of pages in ZONE_DMA.  This approach touchs more of the zfs
code, but it is more consistent with the right way to handle these cases
under Linux.

This is patch lays the ground work for being able to safely revert the
following commits which used PF_MEMALLOC:

  21ade34 Disable direct reclaim for z_wr_* threads
  cfc9a5c Fix zpl_writepage() deadlock
  eec8164 Fix ASSERTION(!dsl_pool_sync_context(tx->tx_pool))

Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #726
2012-08-27 12:01:37 -07:00

445 lines
10 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 http://www.opensolaris.org/os/licensing.
* 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 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Common routines used by zfs and zpool property management.
*/
#include <sys/zio.h>
#include <sys/spa.h>
#include <sys/zfs_acl.h>
#include <sys/zfs_ioctl.h>
#include <sys/zfs_znode.h>
#include <sys/fs/zfs.h>
#include "zfs_prop.h"
#include "zfs_deleg.h"
#if defined(_KERNEL)
#include <sys/systm.h>
#include <util/qsort.h>
#else
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#endif
static zprop_desc_t *
zprop_get_proptable(zfs_type_t type)
{
if (type == ZFS_TYPE_POOL)
return (zpool_prop_get_table());
else
return (zfs_prop_get_table());
}
static int
zprop_get_numprops(zfs_type_t type)
{
if (type == ZFS_TYPE_POOL)
return (ZPOOL_NUM_PROPS);
else
return (ZFS_NUM_PROPS);
}
void
zprop_register_impl(int prop, const char *name, zprop_type_t type,
uint64_t numdefault, const char *strdefault, zprop_attr_t attr,
int objset_types, const char *values, const char *colname,
boolean_t rightalign, boolean_t visible, const zprop_index_t *idx_tbl)
{
zprop_desc_t *prop_tbl = zprop_get_proptable(objset_types);
zprop_desc_t *pd;
pd = &prop_tbl[prop];
ASSERT(pd->pd_name == NULL || pd->pd_name == name);
ASSERT(name != NULL);
ASSERT(colname != NULL);
pd->pd_name = name;
pd->pd_propnum = prop;
pd->pd_proptype = type;
pd->pd_numdefault = numdefault;
pd->pd_strdefault = strdefault;
pd->pd_attr = attr;
pd->pd_types = objset_types;
pd->pd_values = values;
pd->pd_colname = colname;
pd->pd_rightalign = rightalign;
pd->pd_visible = visible;
pd->pd_table = idx_tbl;
pd->pd_table_size = 0;
while (idx_tbl && (idx_tbl++)->pi_name != NULL)
pd->pd_table_size++;
}
void
zprop_register_string(int prop, const char *name, const char *def,
zprop_attr_t attr, int objset_types, const char *values,
const char *colname)
{
zprop_register_impl(prop, name, PROP_TYPE_STRING, 0, def, attr,
objset_types, values, colname, B_FALSE, B_TRUE, NULL);
}
void
zprop_register_number(int prop, const char *name, uint64_t def,
zprop_attr_t attr, int objset_types, const char *values,
const char *colname)
{
zprop_register_impl(prop, name, PROP_TYPE_NUMBER, def, NULL, attr,
objset_types, values, colname, B_TRUE, B_TRUE, NULL);
}
void
zprop_register_index(int prop, const char *name, uint64_t def,
zprop_attr_t attr, int objset_types, const char *values,
const char *colname, const zprop_index_t *idx_tbl)
{
zprop_register_impl(prop, name, PROP_TYPE_INDEX, def, NULL, attr,
objset_types, values, colname, B_TRUE, B_TRUE, idx_tbl);
}
void
zprop_register_hidden(int prop, const char *name, zprop_type_t type,
zprop_attr_t attr, int objset_types, const char *colname)
{
zprop_register_impl(prop, name, type, 0, NULL, attr,
objset_types, NULL, colname, B_FALSE, B_FALSE, NULL);
}
/*
* A comparison function we can use to order indexes into property tables.
*/
static int
zprop_compare(const void *arg1, const void *arg2)
{
const zprop_desc_t *p1 = *((zprop_desc_t **)arg1);
const zprop_desc_t *p2 = *((zprop_desc_t **)arg2);
boolean_t p1ro, p2ro;
p1ro = (p1->pd_attr == PROP_READONLY);
p2ro = (p2->pd_attr == PROP_READONLY);
if (p1ro == p2ro)
return (strcmp(p1->pd_name, p2->pd_name));
return (p1ro ? -1 : 1);
}
/*
* Iterate over all properties in the given property table, calling back
* into the specified function for each property. We will continue to
* iterate until we either reach the end or the callback function returns
* something other than ZPROP_CONT.
*/
int
zprop_iter_common(zprop_func func, void *cb, boolean_t show_all,
boolean_t ordered, zfs_type_t type)
{
int i, j, num_props, size, prop;
zprop_desc_t *prop_tbl;
zprop_desc_t **order;
prop_tbl = zprop_get_proptable(type);
num_props = zprop_get_numprops(type);
size = num_props * sizeof (zprop_desc_t *);
#if defined(_KERNEL)
order = kmem_alloc(size, KM_PUSHPAGE);
#else
if ((order = malloc(size)) == NULL)
return (ZPROP_CONT);
#endif
for (j = 0; j < num_props; j++)
order[j] = &prop_tbl[j];
if (ordered) {
qsort((void *)order, num_props, sizeof (zprop_desc_t *),
zprop_compare);
}
prop = ZPROP_CONT;
for (i = 0; i < num_props; i++) {
if ((order[i]->pd_visible || show_all) &&
(func(order[i]->pd_propnum, cb) != ZPROP_CONT)) {
prop = order[i]->pd_propnum;
break;
}
}
#if defined(_KERNEL)
kmem_free(order, size);
#else
free(order);
#endif
return (prop);
}
static boolean_t
propname_match(const char *p, size_t len, zprop_desc_t *prop_entry)
{
const char *propname = prop_entry->pd_name;
#ifndef _KERNEL
const char *colname = prop_entry->pd_colname;
int c;
#endif
if (len == strlen(propname) &&
strncmp(p, propname, len) == 0)
return (B_TRUE);
#ifndef _KERNEL
if (colname == NULL || len != strlen(colname))
return (B_FALSE);
for (c = 0; c < len; c++)
if (p[c] != tolower(colname[c]))
break;
return (colname[c] == '\0');
#else
return (B_FALSE);
#endif
}
typedef struct name_to_prop_cb {
const char *propname;
zprop_desc_t *prop_tbl;
} name_to_prop_cb_t;
static int
zprop_name_to_prop_cb(int prop, void *cb_data)
{
name_to_prop_cb_t *data = cb_data;
if (propname_match(data->propname, strlen(data->propname),
&data->prop_tbl[prop]))
return (prop);
return (ZPROP_CONT);
}
int
zprop_name_to_prop(const char *propname, zfs_type_t type)
{
int prop;
name_to_prop_cb_t cb_data;
cb_data.propname = propname;
cb_data.prop_tbl = zprop_get_proptable(type);
prop = zprop_iter_common(zprop_name_to_prop_cb, &cb_data,
B_TRUE, B_FALSE, type);
return (prop == ZPROP_CONT ? ZPROP_INVAL : prop);
}
int
zprop_string_to_index(int prop, const char *string, uint64_t *index,
zfs_type_t type)
{
zprop_desc_t *prop_tbl;
const zprop_index_t *idx_tbl;
int i;
if (prop == ZPROP_INVAL || prop == ZPROP_CONT)
return (-1);
ASSERT(prop < zprop_get_numprops(type));
prop_tbl = zprop_get_proptable(type);
if ((idx_tbl = prop_tbl[prop].pd_table) == NULL)
return (-1);
for (i = 0; idx_tbl[i].pi_name != NULL; i++) {
if (strcmp(string, idx_tbl[i].pi_name) == 0) {
*index = idx_tbl[i].pi_value;
return (0);
}
}
return (-1);
}
int
zprop_index_to_string(int prop, uint64_t index, const char **string,
zfs_type_t type)
{
zprop_desc_t *prop_tbl;
const zprop_index_t *idx_tbl;
int i;
if (prop == ZPROP_INVAL || prop == ZPROP_CONT)
return (-1);
ASSERT(prop < zprop_get_numprops(type));
prop_tbl = zprop_get_proptable(type);
if ((idx_tbl = prop_tbl[prop].pd_table) == NULL)
return (-1);
for (i = 0; idx_tbl[i].pi_name != NULL; i++) {
if (idx_tbl[i].pi_value == index) {
*string = idx_tbl[i].pi_name;
return (0);
}
}
return (-1);
}
/*
* Return a random valid property value. Used by ztest.
*/
uint64_t
zprop_random_value(int prop, uint64_t seed, zfs_type_t type)
{
zprop_desc_t *prop_tbl;
const zprop_index_t *idx_tbl;
ASSERT((uint_t)prop < zprop_get_numprops(type));
prop_tbl = zprop_get_proptable(type);
idx_tbl = prop_tbl[prop].pd_table;
if (idx_tbl == NULL)
return (seed);
return (idx_tbl[seed % prop_tbl[prop].pd_table_size].pi_value);
}
const char *
zprop_values(int prop, zfs_type_t type)
{
zprop_desc_t *prop_tbl;
ASSERT(prop != ZPROP_INVAL && prop != ZPROP_CONT);
ASSERT(prop < zprop_get_numprops(type));
prop_tbl = zprop_get_proptable(type);
return (prop_tbl[prop].pd_values);
}
/*
* Returns TRUE if the property applies to any of the given dataset types.
*/
boolean_t
zprop_valid_for_type(int prop, zfs_type_t type)
{
zprop_desc_t *prop_tbl;
if (prop == ZPROP_INVAL || prop == ZPROP_CONT)
return (B_FALSE);
ASSERT(prop < zprop_get_numprops(type));
prop_tbl = zprop_get_proptable(type);
return ((prop_tbl[prop].pd_types & type) != 0);
}
#ifndef _KERNEL
/*
* Determines the minimum width for the column, and indicates whether it's fixed
* or not. Only string columns are non-fixed.
*/
size_t
zprop_width(int prop, boolean_t *fixed, zfs_type_t type)
{
zprop_desc_t *prop_tbl, *pd;
const zprop_index_t *idx;
size_t ret;
int i;
ASSERT(prop != ZPROP_INVAL && prop != ZPROP_CONT);
ASSERT(prop < zprop_get_numprops(type));
prop_tbl = zprop_get_proptable(type);
pd = &prop_tbl[prop];
*fixed = B_TRUE;
/*
* Start with the width of the column name.
*/
ret = strlen(pd->pd_colname);
/*
* For fixed-width values, make sure the width is large enough to hold
* any possible value.
*/
switch (pd->pd_proptype) {
case PROP_TYPE_NUMBER:
/*
* The maximum length of a human-readable number is 5 characters
* ("20.4M", for example).
*/
if (ret < 5)
ret = 5;
/*
* 'creation' is handled specially because it's a number
* internally, but displayed as a date string.
*/
if (prop == ZFS_PROP_CREATION)
*fixed = B_FALSE;
break;
case PROP_TYPE_INDEX:
idx = prop_tbl[prop].pd_table;
for (i = 0; idx[i].pi_name != NULL; i++) {
if (strlen(idx[i].pi_name) > ret)
ret = strlen(idx[i].pi_name);
}
break;
case PROP_TYPE_STRING:
*fixed = B_FALSE;
break;
}
return (ret);
}
#endif
#if defined(_KERNEL) && defined(HAVE_SPL)
/* Common routines to initialize property tables */
EXPORT_SYMBOL(zprop_register_impl);
EXPORT_SYMBOL(zprop_register_string);
EXPORT_SYMBOL(zprop_register_number);
EXPORT_SYMBOL(zprop_register_index);
EXPORT_SYMBOL(zprop_register_hidden);
/* Common routines for zfs and zpool property management */
EXPORT_SYMBOL(zprop_iter_common);
EXPORT_SYMBOL(zprop_name_to_prop);
EXPORT_SYMBOL(zprop_string_to_index);
EXPORT_SYMBOL(zprop_index_to_string);
EXPORT_SYMBOL(zprop_random_value);
EXPORT_SYMBOL(zprop_values);
EXPORT_SYMBOL(zprop_valid_for_type);
#endif