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ext4: add interface to advertise ext4 features in sysfs

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User-space should have the opportunity to check what features doest ext4
support in each particular copy. This adds easy interface by creating new
"features" directory in sys/fs/ext4/. In that directory files
advertising feature names can be created.

Add lazy_itable_init to the feature list.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Lukas Czerner
2010-10-27 21:30:05 -04:00
committed by Theodore Ts'o
parent bfff68738f
commit 857ac889cc
3 changed files with 65 additions and 11 deletions
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52
fs/ext4/super.c
View File

@@ -57,6 +57,7 @@ struct proc_dir_entry *ext4_proc_root;
static struct kset *ext4_kset;
struct ext4_lazy_init *ext4_li_info;
struct mutex ext4_li_mtx;
struct ext4_features *ext4_feat;
static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
unsigned long journal_devnum);
@@ -709,6 +710,7 @@ static void ext4_put_super(struct super_block *sb)
struct ext4_super_block *es = sbi->s_es;
int i, err;
ext4_unregister_li_request(sb);
dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
flush_workqueue(sbi->dio_unwritten_wq);
@@ -727,7 +729,6 @@ static void ext4_put_super(struct super_block *sb)
}
del_timer(&sbi->s_err_report);
ext4_unregister_li_request(sb);
ext4_release_system_zone(sb);
ext4_mb_release(sb);
ext4_ext_release(sb);
@@ -2416,6 +2417,7 @@ static struct ext4_attr ext4_attr_##_name = { \
#define EXT4_ATTR(name, mode, show, store) \
static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
#define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
#define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
#define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
#define EXT4_RW_ATTR_SBI_UI(name, elname) \
@@ -2452,6 +2454,14 @@ static struct attribute *ext4_attrs[] = {
NULL,
};
/* Features this copy of ext4 supports */
EXT4_INFO_ATTR(lazy_itable_init);
static struct attribute *ext4_feat_attrs[] = {
ATTR_LIST(lazy_itable_init),
NULL,
};
static ssize_t ext4_attr_show(struct kobject *kobj,
struct attribute *attr, char *buf)
{
@@ -2480,7 +2490,6 @@ static void ext4_sb_release(struct kobject *kobj)
complete(&sbi->s_kobj_unregister);
}
static const struct sysfs_ops ext4_attr_ops = {
.show = ext4_attr_show,
.store = ext4_attr_store,
@@ -2492,6 +2501,17 @@ static struct kobj_type ext4_ktype = {
.release = ext4_sb_release,
};
static void ext4_feat_release(struct kobject *kobj)
{
complete(&ext4_feat->f_kobj_unregister);
}
static struct kobj_type ext4_feat_ktype = {
.default_attrs = ext4_feat_attrs,
.sysfs_ops = &ext4_attr_ops,
.release = ext4_feat_release,
};
/*
* Check whether this filesystem can be mounted based on
* the features present and the RDONLY/RDWR mount requested.
@@ -4720,6 +4740,30 @@ static struct file_system_type ext4_fs_type = {
.fs_flags = FS_REQUIRES_DEV,
};
int __init ext4_init_feat_adverts(void)
{
struct ext4_features *ef;
int ret = -ENOMEM;
ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
if (!ef)
goto out;
ef->f_kobj.kset = ext4_kset;
init_completion(&ef->f_kobj_unregister);
ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
"features");
if (ret) {
kfree(ef);
goto out;
}
ext4_feat = ef;
ret = 0;
out:
return ret;
}
static int __init init_ext4_fs(void)
{
int err;
@@ -4732,6 +4776,9 @@ static int __init init_ext4_fs(void)
if (!ext4_kset)
goto out4;
ext4_proc_root = proc_mkdir("fs/ext4", NULL);
err = ext4_init_feat_adverts();
err = init_ext4_mballoc();
if (err)
goto out3;
@@ -4760,6 +4807,7 @@ out1:
out2:
exit_ext4_mballoc();
out3:
kfree(ext4_feat);
remove_proc_entry("fs/ext4", NULL);
kset_unregister(ext4_kset);
out4: