Commit 51225039 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
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sysfs: make directory dentries and inodes reclaimable 



This patch makes dentries and inodes for sysfs directories
reclaimable.

* sysfs_notify() is modified to walk sysfs_dirent tree instead of
  dentry tree.

* sysfs_update_file() and sysfs_chmod_file() use sysfs_get_dentry() to
  grab the victim dentry.

* sysfs_rename_dir() and sysfs_move_dir() grab all dentries using
  sysfs_get_dentry() on startup.

* Dentries for all shadowed directories are pinned in memory to serve
  as lookup start point.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 53e0ae92

fs/sysfs/dir.c

+126 −105
Original line number Diff line number Diff line
@@ -568,9 +568,9 @@ static void sysfs_drop_dentry(struct sysfs_dirent *sd) 
	spin_unlock(&dcache_lock);

	spin_unlock(&sysfs_assoc_lock);



	/* dentries for shadowed inodes are pinned, unpin */

	if (dentry && sysfs_is_shadowed_inode(dentry->d_inode))

		dput(dentry);

	/* XXX: unpin if directory, this will go away soon */

	if (sysfs_type(sd) == SYSFS_DIR)

	dput(dentry);



	/* adjust nlink and update timestamp */
@@ -686,69 +686,29 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, 
static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,

		      const char *name, struct sysfs_dirent **p_sd)

{

	struct dentry *parent = parent_sd->s_dentry;

	struct sysfs_addrm_cxt acxt;

	int error;

	umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;

	struct dentry *dentry;

	struct inode *inode;

	struct sysfs_addrm_cxt acxt;

	struct sysfs_dirent *sd;



	sysfs_addrm_start(&acxt, parent_sd);



	/* allocate */

	dentry = lookup_one_len(name, parent, strlen(name));

	if (IS_ERR(dentry)) {

		error = PTR_ERR(dentry);

		goto out_finish;

	}



	error = -EEXIST;

	if (dentry->d_inode)

		goto out_dput;



	error = -ENOMEM;

	sd = sysfs_new_dirent(name, mode, SYSFS_DIR);

	if (!sd)

		goto out_drop;

		return -ENOMEM;

	sd->s_elem.dir.kobj = kobj;



	inode = sysfs_get_inode(sd);

	if (!inode)

		goto out_sput;



	if (inode->i_state & I_NEW) {

		inode->i_op = &sysfs_dir_inode_operations;

		inode->i_fop = &sysfs_dir_operations;

		/* directory inodes start off with i_nlink == 2 (for ".") */

		inc_nlink(inode);

	}



	/* link in */

	error = -EEXIST;

	if (sysfs_find_dirent(parent_sd, name))

		goto out_iput;



	sysfs_addrm_start(&acxt, parent_sd);

	if (!sysfs_find_dirent(parent_sd, name)) {

		sysfs_add_one(&acxt, sd);

		sysfs_link_sibling(sd);

	sysfs_instantiate(dentry, inode);

	sysfs_attach_dentry(sd, dentry);



	}

	if (sysfs_addrm_finish(&acxt)) {

		*p_sd = sd;

	error = 0;

	goto out_finish;	/* pin directory dentry in core */

		return 0;

	}



 out_iput:

	iput(inode);

 out_sput:

	sysfs_put(sd);

 out_drop:

	d_drop(dentry);

 out_dput:

	dput(dentry);

 out_finish:

	sysfs_addrm_finish(&acxt);

	return error;

	return -EEXIST;

}



int sysfs_create_subdir(struct kobject *kobj, const char *name,
@@ -785,6 +745,17 @@ int sysfs_create_dir(struct kobject *kobj, 
	return error;

}



static int sysfs_count_nlink(struct sysfs_dirent *sd)

{

	struct sysfs_dirent *child;

	int nr = 0;



	for (child = sd->s_children; child; child = child->s_sibling)

		if (sysfs_type(child) == SYSFS_DIR)

			nr++;

	return nr + 2;

}



static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,

				struct nameidata *nd)

{
@@ -795,7 +766,7 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, 
	int found = 0;



	for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) {

		if ((sysfs_type(sd) & SYSFS_NOT_PINNED) &&

		if (sysfs_type(sd) &&

		    !strcmp(sd->s_name, dentry->d_name.name)) {

			found = 1;

			break;
@@ -816,6 +787,11 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, 
	if (inode->i_state & I_NEW) {

		/* initialize inode according to type */

		switch (sysfs_type(sd)) {

		case SYSFS_DIR:

			inode->i_op = &sysfs_dir_inode_operations;

			inode->i_fop = &sysfs_dir_operations;

			inode->i_nlink = sysfs_count_nlink(sd);

			break;

		case SYSFS_KOBJ_ATTR:

			inode->i_size = PAGE_SIZE;

			inode->i_fop = &sysfs_file_operations;
@@ -876,7 +852,7 @@ static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) 
	while (*pos) {

		struct sysfs_dirent *sd = *pos;



		if (sysfs_type(sd) && (sysfs_type(sd) & SYSFS_NOT_PINNED)) {

		if (sysfs_type(sd) && sysfs_type(sd) != SYSFS_DIR) {

			*pos = sd->s_sibling;

			sd->s_sibling = NULL;

			sysfs_remove_one(&acxt, sd);
@@ -912,14 +888,25 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, 
		     const char *new_name)

{

	struct sysfs_dirent *sd = kobj->sd;

	struct dentry *new_parent = new_parent_sd->s_dentry;

	struct dentry *new_dentry;

	char *dup_name;

	struct dentry *new_parent = NULL;

	struct dentry *old_dentry = NULL, *new_dentry = NULL;

	const char *dup_name = NULL;

	int error;



	if (!new_parent_sd)

		return -EFAULT;

	/* get dentries */

	old_dentry = sysfs_get_dentry(sd);

	if (IS_ERR(old_dentry)) {

		error = PTR_ERR(old_dentry);

		goto out_dput;

	}



	new_parent = sysfs_get_dentry(new_parent_sd);

	if (IS_ERR(new_parent)) {

		error = PTR_ERR(new_parent);

		goto out_dput;

	}



	/* lock new_parent and get dentry for new name */

	mutex_lock(&new_parent->d_inode->i_mutex);



	new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
@@ -933,14 +920,14 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, 
	 * shadows of the same directory

	 */

	error = -EINVAL;

	if (sd->s_parent->s_dentry->d_inode != new_parent->d_inode ||

	if (old_dentry->d_parent->d_inode != new_parent->d_inode ||

	    new_dentry->d_parent->d_inode != new_parent->d_inode ||

	    new_dentry == sd->s_dentry)

		goto out_dput;

	    old_dentry == new_dentry)

		goto out_unlock;



	error = -EEXIST;

	if (new_dentry->d_inode)

		goto out_dput;

		goto out_unlock;



	/* rename kobject and sysfs_dirent */

	error = -ENOMEM;
@@ -950,9 +937,9 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, 


	error = kobject_set_name(kobj, "%s", new_name);

	if (error)

		goto out_free;

		goto out_drop;



	kfree(sd->s_name);

	dup_name = sd->s_name;

	sd->s_name = new_name;



	/* move under the new parent */
@@ -972,45 +959,58 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, 
	error = 0;

	goto out_unlock;



 out_free:

	kfree(dup_name);

 out_drop:

	d_drop(new_dentry);

 out_dput:

	dput(new_dentry);

 out_unlock:

	mutex_unlock(&new_parent->d_inode->i_mutex);

 out_dput:

	kfree(dup_name);

	dput(new_parent);

	dput(old_dentry);

	dput(new_dentry);

	return error;

}



int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)

int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)

{

	struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;

	struct sysfs_dirent *new_parent_sd, *sd;

	struct sysfs_dirent *sd = kobj->sd;

	struct sysfs_dirent *new_parent_sd;

	struct dentry *old_parent, *new_parent = NULL;

	struct dentry *old_dentry = NULL, *new_dentry = NULL;

	int error;



	old_parent_dentry = kobj->parent ?

		kobj->parent->sd->s_dentry : sysfs_mount->mnt_sb->s_root;

	new_parent_dentry = new_parent ?

		new_parent->sd->s_dentry : sysfs_mount->mnt_sb->s_root;

	BUG_ON(!sd->s_parent);

	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;



	/* get dentries */

	old_dentry = sysfs_get_dentry(sd);

	if (IS_ERR(old_dentry)) {

		error = PTR_ERR(old_dentry);

		goto out_dput;

	}

	old_parent = sd->s_parent->s_dentry;



	new_parent = sysfs_get_dentry(new_parent_sd);

	if (IS_ERR(new_parent)) {

		error = PTR_ERR(new_parent);

		goto out_dput;

	}



	if (old_parent_dentry->d_inode == new_parent_dentry->d_inode)

		return 0;	/* nothing to move */

	if (old_parent->d_inode == new_parent->d_inode) {

		error = 0;

		goto out_dput;	/* nothing to move */

	}

again:

	mutex_lock(&old_parent_dentry->d_inode->i_mutex);

	if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {

		mutex_unlock(&old_parent_dentry->d_inode->i_mutex);

	mutex_lock(&old_parent->d_inode->i_mutex);

	if (!mutex_trylock(&new_parent->d_inode->i_mutex)) {

		mutex_unlock(&old_parent->d_inode->i_mutex);

		goto again;

	}



	new_parent_sd = new_parent_dentry->d_fsdata;

	sd = kobj->sd;



	new_dentry = lookup_one_len(kobj->name, new_parent_dentry,

				    strlen(kobj->name));

	new_dentry = lookup_one_len(kobj->name, new_parent, strlen(kobj->name));

	if (IS_ERR(new_dentry)) {

		error = PTR_ERR(new_dentry);

		goto out;

		goto out_unlock;

	} else

		error = 0;

	d_add(new_dentry, NULL);
@@ -1027,10 +1027,14 @@ again: 
	sysfs_link_sibling(sd);



	mutex_unlock(&sysfs_mutex);

out:

	mutex_unlock(&new_parent_dentry->d_inode->i_mutex);

	mutex_unlock(&old_parent_dentry->d_inode->i_mutex);



 out_unlock:

	mutex_unlock(&new_parent->d_inode->i_mutex);

	mutex_unlock(&old_parent->d_inode->i_mutex);

 out_dput:

	dput(new_parent);

	dput(old_dentry);

	dput(new_dentry);

	return error;

}
@@ -1191,12 +1195,20 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) 
int sysfs_make_shadowed_dir(struct kobject *kobj,

	void * (*follow_link)(struct dentry *, struct nameidata *))

{

	struct dentry *dentry;

	struct inode *inode;

	struct inode_operations *i_op;



	inode = kobj->sd->s_dentry->d_inode;

	if (inode->i_op != &sysfs_dir_inode_operations)

	/* get dentry for @kobj->sd, dentry of a shadowed dir is pinned */

	dentry = sysfs_get_dentry(kobj->sd);

	if (IS_ERR(dentry))

		return PTR_ERR(dentry);



	inode = dentry->d_inode;

	if (inode->i_op != &sysfs_dir_inode_operations) {

		dput(dentry);

		return -EINVAL;

	}



	i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);

	if (!i_op)
@@ -1223,17 +1235,23 @@ int sysfs_make_shadowed_dir(struct kobject *kobj, 


struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj)

{

	struct dentry *dir = kobj->sd->s_dentry;

	struct inode *inode = dir->d_inode;

	struct dentry *parent = dir->d_parent;

	struct sysfs_dirent *parent_sd = parent->d_fsdata;

	struct dentry *shadow;

	struct sysfs_dirent *parent_sd = kobj->sd->s_parent;

	struct dentry *dir, *parent, *shadow;

	struct inode *inode;

	struct sysfs_dirent *sd;

	struct sysfs_addrm_cxt acxt;



	dir = sysfs_get_dentry(kobj->sd);

	if (IS_ERR(dir)) {

		sd = (void *)dir;

		goto out;

	}

	parent = dir->d_parent;



	inode = dir->d_inode;

	sd = ERR_PTR(-EINVAL);

	if (!sysfs_is_shadowed_inode(inode))

		goto out;

		goto out_dput;



	shadow = d_alloc(parent, &dir->d_name);

	if (!shadow)
@@ -1258,12 +1276,15 @@ struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj) 


	dget(shadow);		/* Extra count - pin the dentry in core */



out:

	return sd;

	goto out_dput;



 nomem:

	dput(shadow);

	sd = ERR_PTR(-ENOMEM);

	goto out;

 out_dput:

	dput(dir);

 out:

	return sd;

}



/**

fs/sysfs/file.c

+59 −75
Original line number Diff line number Diff line
@@ -362,43 +362,22 @@ static unsigned int sysfs_poll(struct file *filp, poll_table *wait) 
	return POLLERR|POLLPRI;

}





static struct dentry *step_down(struct dentry *dir, const char * name)

{

	struct dentry * de;



	if (dir == NULL || dir->d_inode == NULL)

		return NULL;



	mutex_lock(&dir->d_inode->i_mutex);

	de = lookup_one_len(name, dir, strlen(name));

	mutex_unlock(&dir->d_inode->i_mutex);

	dput(dir);

	if (IS_ERR(de))

		return NULL;

	if (de->d_inode == NULL) {

		dput(de);

		return NULL;

	}

	return de;

}



void sysfs_notify(struct kobject *k, char *dir, char *attr)

{

	struct dentry *de = k->sd->s_dentry;

	if (de)

		dget(de);

	if (de && dir)

		de = step_down(de, dir);

	if (de && attr)

		de = step_down(de, attr);

	if (de) {

		struct sysfs_dirent * sd = de->d_fsdata;

		if (sd)

	struct sysfs_dirent *sd = k->sd;



	mutex_lock(&sysfs_mutex);



	if (sd && dir)

		sd = sysfs_find_dirent(sd, dir);

	if (sd && attr)

		sd = sysfs_find_dirent(sd, attr);

	if (sd) {

		atomic_inc(&sd->s_event);

		wake_up_interruptible(&k->poll);

		dput(de);

	}



	mutex_unlock(&sysfs_mutex);

}

EXPORT_SYMBOL_GPL(sysfs_notify);
@@ -485,30 +464,31 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); 
 */

int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)

{

	struct dentry *dir = kobj->sd->s_dentry;

	struct dentry * victim;

	int res = -ENOENT;



	mutex_lock(&dir->d_inode->i_mutex);

	victim = lookup_one_len(attr->name, dir, strlen(attr->name));

	if (!IS_ERR(victim)) {

		/* make sure dentry is really there */

		if (victim->d_inode && 

		    (victim->d_parent->d_inode == dir->d_inode)) {

			victim->d_inode->i_mtime = CURRENT_TIME;

			fsnotify_modify(victim);

			res = 0;

		} else

			d_drop(victim);

	struct sysfs_dirent *victim_sd = NULL;

	struct dentry *victim = NULL;

	int rc;



		/**

		 * Drop the reference acquired from lookup_one_len() above.

		 */

		dput(victim);

	rc = -ENOENT;

	victim_sd = sysfs_get_dirent(kobj->sd, attr->name);

	if (!victim_sd)

		goto out;



	victim = sysfs_get_dentry(victim_sd);

	if (IS_ERR(victim)) {

		rc = PTR_ERR(victim);

		victim = NULL;

		goto out;

	}

	mutex_unlock(&dir->d_inode->i_mutex);



	return res;

	mutex_lock(&victim->d_inode->i_mutex);

	victim->d_inode->i_mtime = CURRENT_TIME;

	fsnotify_modify(victim);

	mutex_unlock(&victim->d_inode->i_mutex);

	rc = 0;

 out:

	dput(victim);

	sysfs_put(victim_sd);

	return rc;

}
@@ -521,30 +501,34 @@ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr) 
 */

int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)

{

	struct dentry *dir = kobj->sd->s_dentry;

	struct dentry *victim;

	struct sysfs_dirent *victim_sd = NULL;

	struct dentry *victim = NULL;

	struct inode * inode;

	struct iattr newattrs;

	int res = -ENOENT;

	int rc;



	rc = -ENOENT;

	victim_sd = sysfs_get_dirent(kobj->sd, attr->name);

	if (!victim_sd)

		goto out;



	victim = sysfs_get_dentry(victim_sd);

	if (IS_ERR(victim)) {

		rc = PTR_ERR(victim);

		victim = NULL;

		goto out;

	}



	mutex_lock(&dir->d_inode->i_mutex);

	victim = lookup_one_len(attr->name, dir, strlen(attr->name));

	if (!IS_ERR(victim)) {

		if (victim->d_inode &&

		    (victim->d_parent->d_inode == dir->d_inode)) {

	inode = victim->d_inode;

	mutex_lock(&inode->i_mutex);

			newattrs.ia_mode = (mode & S_IALLUGO) |

						(inode->i_mode & ~S_IALLUGO);

	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);

	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;

			res = notify_change(victim, &newattrs);

	rc = notify_change(victim, &newattrs);

	mutex_unlock(&inode->i_mutex);

		}

 out:

	dput(victim);

	}

	mutex_unlock(&dir->d_inode->i_mutex);



	return res;

	sysfs_put(victim_sd);

	return rc;

}

EXPORT_SYMBOL_GPL(sysfs_chmod_file);

fs/sysfs/mount.c

+1 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ static const struct super_operations sysfs_ops = { 
	.drop_inode	= sysfs_delete_inode,

};



static struct sysfs_dirent sysfs_root = {

struct sysfs_dirent sysfs_root = {

	.s_count	= ATOMIC_INIT(1),

	.s_flags	= SYSFS_ROOT,

	.s_mode		= S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,

fs/sysfs/sysfs.h

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ struct sysfs_addrm_cxt { 
};



extern struct vfsmount * sysfs_mount;

extern struct sysfs_dirent sysfs_root;

extern struct kmem_cache *sysfs_dir_cachep;



extern struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd);

include/linux/sysfs.h

+0 −1
Original line number Diff line number Diff line
@@ -81,7 +81,6 @@ struct sysfs_ops { 
#define SYSFS_KOBJ_ATTR 	0x0004

#define SYSFS_KOBJ_BIN_ATTR	0x0008

#define SYSFS_KOBJ_LINK 	0x0020

#define SYSFS_NOT_PINNED	(SYSFS_KOBJ_ATTR | SYSFS_KOBJ_BIN_ATTR | SYSFS_KOBJ_LINK)

#define SYSFS_COPY_NAME		(SYSFS_DIR | SYSFS_KOBJ_LINK)



#define SYSFS_FLAG_MASK		~SYSFS_TYPE_MASK

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