https://github.com/torvalds/linux
Tip revision: a798c10faf62a505d24e5f6213fbaf904a39623f authored by Linus Torvalds on 20 April 2014, 18:08:50 UTC
Linux 3.15-rc2
Linux 3.15-rc2
Tip revision: a798c10
sysfs.c
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/kobject.h>
#include <linux/bug.h>
#include <linux/genhd.h>
#include <linux/debugfs.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "sysfs.h"
#include "volumes.h"
static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
static u64 get_features(struct btrfs_fs_info *fs_info,
enum btrfs_feature_set set)
{
struct btrfs_super_block *disk_super = fs_info->super_copy;
if (set == FEAT_COMPAT)
return btrfs_super_compat_flags(disk_super);
else if (set == FEAT_COMPAT_RO)
return btrfs_super_compat_ro_flags(disk_super);
else
return btrfs_super_incompat_flags(disk_super);
}
static void set_features(struct btrfs_fs_info *fs_info,
enum btrfs_feature_set set, u64 features)
{
struct btrfs_super_block *disk_super = fs_info->super_copy;
if (set == FEAT_COMPAT)
btrfs_set_super_compat_flags(disk_super, features);
else if (set == FEAT_COMPAT_RO)
btrfs_set_super_compat_ro_flags(disk_super, features);
else
btrfs_set_super_incompat_flags(disk_super, features);
}
static int can_modify_feature(struct btrfs_feature_attr *fa)
{
int val = 0;
u64 set, clear;
switch (fa->feature_set) {
case FEAT_COMPAT:
set = BTRFS_FEATURE_COMPAT_SAFE_SET;
clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
break;
case FEAT_COMPAT_RO:
set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
break;
case FEAT_INCOMPAT:
set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
break;
default:
printk(KERN_WARNING "btrfs: sysfs: unknown feature set %d\n",
fa->feature_set);
return 0;
}
if (set & fa->feature_bit)
val |= 1;
if (clear & fa->feature_bit)
val |= 2;
return val;
}
static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
struct kobj_attribute *a, char *buf)
{
int val = 0;
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
if (fs_info) {
u64 features = get_features(fs_info, fa->feature_set);
if (features & fa->feature_bit)
val = 1;
} else
val = can_modify_feature(fa);
return snprintf(buf, PAGE_SIZE, "%d\n", val);
}
static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
struct kobj_attribute *a,
const char *buf, size_t count)
{
struct btrfs_fs_info *fs_info;
struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
struct btrfs_trans_handle *trans;
u64 features, set, clear;
unsigned long val;
int ret;
fs_info = to_fs_info(kobj);
if (!fs_info)
return -EPERM;
ret = kstrtoul(skip_spaces(buf), 0, &val);
if (ret)
return ret;
if (fa->feature_set == FEAT_COMPAT) {
set = BTRFS_FEATURE_COMPAT_SAFE_SET;
clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
} else if (fa->feature_set == FEAT_COMPAT_RO) {
set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
} else {
set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
}
features = get_features(fs_info, fa->feature_set);
/* Nothing to do */
if ((val && (features & fa->feature_bit)) ||
(!val && !(features & fa->feature_bit)))
return count;
if ((val && !(set & fa->feature_bit)) ||
(!val && !(clear & fa->feature_bit))) {
btrfs_info(fs_info,
"%sabling feature %s on mounted fs is not supported.",
val ? "En" : "Dis", fa->kobj_attr.attr.name);
return -EPERM;
}
btrfs_info(fs_info, "%s %s feature flag",
val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
trans = btrfs_start_transaction(fs_info->fs_root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
spin_lock(&fs_info->super_lock);
features = get_features(fs_info, fa->feature_set);
if (val)
features |= fa->feature_bit;
else
features &= ~fa->feature_bit;
set_features(fs_info, fa->feature_set, features);
spin_unlock(&fs_info->super_lock);
ret = btrfs_commit_transaction(trans, fs_info->fs_root);
if (ret)
return ret;
return count;
}
static umode_t btrfs_feature_visible(struct kobject *kobj,
struct attribute *attr, int unused)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
umode_t mode = attr->mode;
if (fs_info) {
struct btrfs_feature_attr *fa;
u64 features;
fa = attr_to_btrfs_feature_attr(attr);
features = get_features(fs_info, fa->feature_set);
if (can_modify_feature(fa))
mode |= S_IWUSR;
else if (!(features & fa->feature_bit))
mode = 0;
}
return mode;
}
BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
static struct attribute *btrfs_supported_feature_attrs[] = {
BTRFS_FEAT_ATTR_PTR(mixed_backref),
BTRFS_FEAT_ATTR_PTR(default_subvol),
BTRFS_FEAT_ATTR_PTR(mixed_groups),
BTRFS_FEAT_ATTR_PTR(compress_lzo),
BTRFS_FEAT_ATTR_PTR(big_metadata),
BTRFS_FEAT_ATTR_PTR(extended_iref),
BTRFS_FEAT_ATTR_PTR(raid56),
BTRFS_FEAT_ATTR_PTR(skinny_metadata),
BTRFS_FEAT_ATTR_PTR(no_holes),
NULL
};
static const struct attribute_group btrfs_feature_attr_group = {
.name = "features",
.is_visible = btrfs_feature_visible,
.attrs = btrfs_supported_feature_attrs,
};
static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
{
u64 val;
if (lock)
spin_lock(lock);
val = *value_ptr;
if (lock)
spin_unlock(lock);
return snprintf(buf, PAGE_SIZE, "%llu\n", val);
}
static ssize_t global_rsv_size_show(struct kobject *kobj,
struct kobj_attribute *ka, char *buf)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
}
BTRFS_ATTR(global_rsv_size, 0444, global_rsv_size_show);
static ssize_t global_rsv_reserved_show(struct kobject *kobj,
struct kobj_attribute *a, char *buf)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
}
BTRFS_ATTR(global_rsv_reserved, 0444, global_rsv_reserved_show);
#define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
static ssize_t raid_bytes_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf);
BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
static ssize_t raid_bytes_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
struct btrfs_block_group_cache *block_group;
int index = kobj - sinfo->block_group_kobjs;
u64 val = 0;
down_read(&sinfo->groups_sem);
list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
val += block_group->key.offset;
else
val += btrfs_block_group_used(&block_group->item);
}
up_read(&sinfo->groups_sem);
return snprintf(buf, PAGE_SIZE, "%llu\n", val);
}
static struct attribute *raid_attributes[] = {
BTRFS_RAID_ATTR_PTR(total_bytes),
BTRFS_RAID_ATTR_PTR(used_bytes),
NULL
};
static void release_raid_kobj(struct kobject *kobj)
{
kobject_put(kobj->parent);
}
struct kobj_type btrfs_raid_ktype = {
.sysfs_ops = &kobj_sysfs_ops,
.release = release_raid_kobj,
.default_attrs = raid_attributes,
};
#define SPACE_INFO_ATTR(field) \
static ssize_t btrfs_space_info_show_##field(struct kobject *kobj, \
struct kobj_attribute *a, \
char *buf) \
{ \
struct btrfs_space_info *sinfo = to_space_info(kobj); \
return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf); \
} \
BTRFS_ATTR(field, 0444, btrfs_space_info_show_##field)
static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
struct kobj_attribute *a,
char *buf)
{
struct btrfs_space_info *sinfo = to_space_info(kobj);
s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
return snprintf(buf, PAGE_SIZE, "%lld\n", val);
}
SPACE_INFO_ATTR(flags);
SPACE_INFO_ATTR(total_bytes);
SPACE_INFO_ATTR(bytes_used);
SPACE_INFO_ATTR(bytes_pinned);
SPACE_INFO_ATTR(bytes_reserved);
SPACE_INFO_ATTR(bytes_may_use);
SPACE_INFO_ATTR(disk_used);
SPACE_INFO_ATTR(disk_total);
BTRFS_ATTR(total_bytes_pinned, 0444, btrfs_space_info_show_total_bytes_pinned);
static struct attribute *space_info_attrs[] = {
BTRFS_ATTR_PTR(flags),
BTRFS_ATTR_PTR(total_bytes),
BTRFS_ATTR_PTR(bytes_used),
BTRFS_ATTR_PTR(bytes_pinned),
BTRFS_ATTR_PTR(bytes_reserved),
BTRFS_ATTR_PTR(bytes_may_use),
BTRFS_ATTR_PTR(disk_used),
BTRFS_ATTR_PTR(disk_total),
BTRFS_ATTR_PTR(total_bytes_pinned),
NULL,
};
static void space_info_release(struct kobject *kobj)
{
struct btrfs_space_info *sinfo = to_space_info(kobj);
percpu_counter_destroy(&sinfo->total_bytes_pinned);
kfree(sinfo);
}
struct kobj_type space_info_ktype = {
.sysfs_ops = &kobj_sysfs_ops,
.release = space_info_release,
.default_attrs = space_info_attrs,
};
static const struct attribute *allocation_attrs[] = {
BTRFS_ATTR_PTR(global_rsv_reserved),
BTRFS_ATTR_PTR(global_rsv_size),
NULL,
};
static ssize_t btrfs_label_show(struct kobject *kobj,
struct kobj_attribute *a, char *buf)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label);
}
static ssize_t btrfs_label_store(struct kobject *kobj,
struct kobj_attribute *a,
const char *buf, size_t len)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
struct btrfs_trans_handle *trans;
struct btrfs_root *root = fs_info->fs_root;
int ret;
if (len >= BTRFS_LABEL_SIZE) {
pr_err("BTRFS: unable to set label with more than %d bytes\n",
BTRFS_LABEL_SIZE - 1);
return -EINVAL;
}
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
spin_lock(&root->fs_info->super_lock);
strcpy(fs_info->super_copy->label, buf);
spin_unlock(&root->fs_info->super_lock);
ret = btrfs_commit_transaction(trans, root);
if (!ret)
return len;
return ret;
}
BTRFS_ATTR_RW(label, 0644, btrfs_label_show, btrfs_label_store);
static struct attribute *btrfs_attrs[] = {
BTRFS_ATTR_PTR(label),
NULL,
};
static void btrfs_release_super_kobj(struct kobject *kobj)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
complete(&fs_info->kobj_unregister);
}
static struct kobj_type btrfs_ktype = {
.sysfs_ops = &kobj_sysfs_ops,
.release = btrfs_release_super_kobj,
.default_attrs = btrfs_attrs,
};
static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
{
if (kobj->ktype != &btrfs_ktype)
return NULL;
return container_of(kobj, struct btrfs_fs_info, super_kobj);
}
#define NUM_FEATURE_BITS 64
static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
static u64 supported_feature_masks[3] = {
[FEAT_COMPAT] = BTRFS_FEATURE_COMPAT_SUPP,
[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
[FEAT_INCOMPAT] = BTRFS_FEATURE_INCOMPAT_SUPP,
};
static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
{
int set;
for (set = 0; set < FEAT_MAX; set++) {
int i;
struct attribute *attrs[2];
struct attribute_group agroup = {
.name = "features",
.attrs = attrs,
};
u64 features = get_features(fs_info, set);
features &= ~supported_feature_masks[set];
if (!features)
continue;
attrs[1] = NULL;
for (i = 0; i < NUM_FEATURE_BITS; i++) {
struct btrfs_feature_attr *fa;
if (!(features & (1ULL << i)))
continue;
fa = &btrfs_feature_attrs[set][i];
attrs[0] = &fa->kobj_attr.attr;
if (add) {
int ret;
ret = sysfs_merge_group(&fs_info->super_kobj,
&agroup);
if (ret)
return ret;
} else
sysfs_unmerge_group(&fs_info->super_kobj,
&agroup);
}
}
return 0;
}
static void __btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
{
kobject_del(&fs_info->super_kobj);
kobject_put(&fs_info->super_kobj);
wait_for_completion(&fs_info->kobj_unregister);
}
void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
{
if (fs_info->space_info_kobj) {
sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
kobject_del(fs_info->space_info_kobj);
kobject_put(fs_info->space_info_kobj);
}
kobject_del(fs_info->device_dir_kobj);
kobject_put(fs_info->device_dir_kobj);
addrm_unknown_feature_attrs(fs_info, false);
sysfs_remove_group(&fs_info->super_kobj, &btrfs_feature_attr_group);
__btrfs_sysfs_remove_one(fs_info);
}
const char * const btrfs_feature_set_names[3] = {
[FEAT_COMPAT] = "compat",
[FEAT_COMPAT_RO] = "compat_ro",
[FEAT_INCOMPAT] = "incompat",
};
char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
{
size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
int len = 0;
int i;
char *str;
str = kmalloc(bufsize, GFP_KERNEL);
if (!str)
return str;
for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
const char *name;
if (!(flags & (1ULL << i)))
continue;
name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
len += snprintf(str + len, bufsize - len, "%s%s",
len ? "," : "", name);
}
return str;
}
static void init_feature_attrs(void)
{
struct btrfs_feature_attr *fa;
int set, i;
BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
ARRAY_SIZE(btrfs_feature_attrs));
BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
ARRAY_SIZE(btrfs_feature_attrs[0]));
memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
memset(btrfs_unknown_feature_names, 0,
sizeof(btrfs_unknown_feature_names));
for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
struct btrfs_feature_attr *sfa;
struct attribute *a = btrfs_supported_feature_attrs[i];
int bit;
sfa = attr_to_btrfs_feature_attr(a);
bit = ilog2(sfa->feature_bit);
fa = &btrfs_feature_attrs[sfa->feature_set][bit];
fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
}
for (set = 0; set < FEAT_MAX; set++) {
for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
char *name = btrfs_unknown_feature_names[set][i];
fa = &btrfs_feature_attrs[set][i];
if (fa->kobj_attr.attr.name)
continue;
snprintf(name, 13, "%s:%u",
btrfs_feature_set_names[set], i);
fa->kobj_attr.attr.name = name;
fa->kobj_attr.attr.mode = S_IRUGO;
fa->feature_set = set;
fa->feature_bit = 1ULL << i;
}
}
}
static int add_device_membership(struct btrfs_fs_info *fs_info)
{
int error = 0;
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
struct btrfs_device *dev;
fs_info->device_dir_kobj = kobject_create_and_add("devices",
&fs_info->super_kobj);
if (!fs_info->device_dir_kobj)
return -ENOMEM;
list_for_each_entry(dev, &fs_devices->devices, dev_list) {
struct hd_struct *disk;
struct kobject *disk_kobj;
if (!dev->bdev)
continue;
disk = dev->bdev->bd_part;
disk_kobj = &part_to_dev(disk)->kobj;
error = sysfs_create_link(fs_info->device_dir_kobj,
disk_kobj, disk_kobj->name);
if (error)
break;
}
return error;
}
/* /sys/fs/btrfs/ entry */
static struct kset *btrfs_kset;
/* /sys/kernel/debug/btrfs */
static struct dentry *btrfs_debugfs_root_dentry;
/* Debugging tunables and exported data */
u64 btrfs_debugfs_test;
int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
{
int error;
init_completion(&fs_info->kobj_unregister);
fs_info->super_kobj.kset = btrfs_kset;
error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
"%pU", fs_info->fsid);
if (error)
return error;
error = sysfs_create_group(&fs_info->super_kobj,
&btrfs_feature_attr_group);
if (error) {
__btrfs_sysfs_remove_one(fs_info);
return error;
}
error = addrm_unknown_feature_attrs(fs_info, true);
if (error)
goto failure;
error = add_device_membership(fs_info);
if (error)
goto failure;
fs_info->space_info_kobj = kobject_create_and_add("allocation",
&fs_info->super_kobj);
if (!fs_info->space_info_kobj) {
error = -ENOMEM;
goto failure;
}
error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
if (error)
goto failure;
return 0;
failure:
btrfs_sysfs_remove_one(fs_info);
return error;
}
static int btrfs_init_debugfs(void)
{
#ifdef CONFIG_DEBUG_FS
btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
if (!btrfs_debugfs_root_dentry)
return -ENOMEM;
debugfs_create_u64("test", S_IRUGO | S_IWUGO, btrfs_debugfs_root_dentry,
&btrfs_debugfs_test);
#endif
return 0;
}
int btrfs_init_sysfs(void)
{
int ret;
btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
if (!btrfs_kset)
return -ENOMEM;
ret = btrfs_init_debugfs();
if (ret)
return ret;
init_feature_attrs();
ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
return ret;
}
void btrfs_exit_sysfs(void)
{
sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
kset_unregister(btrfs_kset);
debugfs_remove_recursive(btrfs_debugfs_root_dentry);
}