Commit 857ac889 authored by Lukas Czerner's avatar Lukas Czerner Committed by Theodore Ts'o
Browse files

ext4: add interface to advertise ext4 features in sysfs 



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: default avatarLukas Czerner <lczerner@redhat.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent bfff6873

fs/ext4/ext4.h

+5 −0
Original line number Original line Diff line number Diff line
@@ -1574,6 +1574,11 @@ struct ext4_li_request { 
	unsigned long		lr_timeout;

	unsigned long		lr_timeout;

};

};





struct ext4_features {

	struct kobject f_kobj;

	struct completion f_kobj_unregister;

};



/*

/*

 * Function prototypes

 * Function prototypes

 */

 */

fs/ext4/ialloc.c

+10 −9
Original line number Original line Diff line number Diff line
@@ -1274,6 +1274,16 @@ extern int ext4_init_inode_table(struct super_block *sb, ext4_group_t group, 
			    ext4_itable_unused_count(sb, gdp)),

			    ext4_itable_unused_count(sb, gdp)),

			    sbi->s_inodes_per_block);

			    sbi->s_inodes_per_block);





	if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {

		ext4_error(sb, "Something is wrong with group %u\n"

			   "Used itable blocks: %d"

			   "itable unused count: %u\n",

			   group, used_blks,

			   ext4_itable_unused_count(sb, gdp));

		ret = 1;

		goto out;

	}



	blk = ext4_inode_table(sb, gdp) + used_blks;

	blk = ext4_inode_table(sb, gdp) + used_blks;

	num = sbi->s_itb_per_group - used_blks;

	num = sbi->s_itb_per_group - used_blks;
@@ -1283,15 +1293,6 @@ extern int ext4_init_inode_table(struct super_block *sb, ext4_group_t group, 
	if (ret)

	if (ret)

		goto err_out;

		goto err_out;





	if (unlikely(num > EXT4_INODES_PER_GROUP(sb))) {

		ext4_error(sb, "Something is wrong with group %u\n"

			   "Used itable blocks: %d"

			   "Itable blocks per group: %lu\n",

			   group, used_blks, sbi->s_itb_per_group);

		ret = 1;

		goto err_out;

	}



	/*

	/*

	 * Skip zeroout if the inode table is full. But we set the ZEROED

	 * Skip zeroout if the inode table is full. But we set the ZEROED

	 * flag anyway, because obviously, when it is full it does not need

	 * flag anyway, because obviously, when it is full it does not need

fs/ext4/super.c

+50 −2
Original line number Original line Diff line number Diff line
@@ -57,6 +57,7 @@ struct proc_dir_entry *ext4_proc_root; 
static struct kset *ext4_kset;

static struct kset *ext4_kset;

struct ext4_lazy_init *ext4_li_info;

struct ext4_lazy_init *ext4_li_info;

struct mutex ext4_li_mtx;

struct mutex ext4_li_mtx;

struct ext4_features *ext4_feat;





static int ext4_load_journal(struct super_block *, struct ext4_super_block *,

static int ext4_load_journal(struct super_block *, struct ext4_super_block *,

			     unsigned long journal_devnum);

			     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;

	struct ext4_super_block *es = sbi->s_es;

	int i, err;

	int i, err;





	ext4_unregister_li_request(sb);

	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);

	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);





	flush_workqueue(sbi->dio_unwritten_wq);

	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);

	del_timer(&sbi->s_err_report);

	ext4_unregister_li_request(sb);

	ext4_release_system_zone(sb);

	ext4_release_system_zone(sb);

	ext4_mb_release(sb);

	ext4_mb_release(sb);

	ext4_ext_release(sb);

	ext4_ext_release(sb);
@@ -2416,6 +2417,7 @@ static struct ext4_attr ext4_attr_##_name = { \ 
#define EXT4_ATTR(name, mode, show, store) \

#define EXT4_ATTR(name, mode, show, store) \

static struct ext4_attr ext4_attr_##name = __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_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(name) EXT4_ATTR(name, 0644, name##_show, name##_store)

#define EXT4_RW_ATTR_SBI_UI(name, elname)	\

#define EXT4_RW_ATTR_SBI_UI(name, elname)	\
@@ -2452,6 +2454,14 @@ static struct attribute *ext4_attrs[] = { 
	NULL,

	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,

static ssize_t ext4_attr_show(struct kobject *kobj,

			      struct attribute *attr, char *buf)

			      struct attribute *attr, char *buf)

{

{
@@ -2480,7 +2490,6 @@ static void ext4_sb_release(struct kobject *kobj) 
	complete(&sbi->s_kobj_unregister);

	complete(&sbi->s_kobj_unregister);

}

}







static const struct sysfs_ops ext4_attr_ops = {

static const struct sysfs_ops ext4_attr_ops = {

	.show	= ext4_attr_show,

	.show	= ext4_attr_show,

	.store	= ext4_attr_store,

	.store	= ext4_attr_store,
@@ -2492,6 +2501,17 @@ static struct kobj_type ext4_ktype = { 
	.release	= ext4_sb_release,

	.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

 * Check whether this filesystem can be mounted based on

 * the features present and the RDONLY/RDWR mount requested.

 * 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,

	.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)

static int __init init_ext4_fs(void)

{

{

	int err;

	int err;
@@ -4732,6 +4776,9 @@ static int __init init_ext4_fs(void) 
	if (!ext4_kset)

	if (!ext4_kset)

		goto out4;

		goto out4;

	ext4_proc_root = proc_mkdir("fs/ext4", NULL);

	ext4_proc_root = proc_mkdir("fs/ext4", NULL);



	err = ext4_init_feat_adverts();



	err = init_ext4_mballoc();

	err = init_ext4_mballoc();

	if (err)

	if (err)

		goto out3;

		goto out3;
@@ -4760,6 +4807,7 @@ out1: 
out2:

out2:

	exit_ext4_mballoc();

	exit_ext4_mballoc();

out3:

out3:

	kfree(ext4_feat);

	remove_proc_entry("fs/ext4", NULL);

	remove_proc_entry("fs/ext4", NULL);

	kset_unregister(ext4_kset);

	kset_unregister(ext4_kset);

out4:

out4:

CRA Git | Maintained and supported by SUSTech CRA and CCSE