sysfs backing store (leaves only)

diff -puN include/linux/sysfs.h~sysfs-leaves-mount include/linux/sysfs.h
@@ -9,6 +9,8 @@
 #ifndef _SYSFS_H_
 #define _SYSFS_H_
 
+#include <asm/atomic.h>
+
 struct kobject;
 struct module;
 

@@ -33,6 +35,21 @@ struct sysfs_ops {
 	ssize_t	(*store)(struct kobject *,struct attribute *,const char *, size_t);
 };
 
+struct sysfs_dirent {
+	atomic_t		s_count;
+	struct list_head	s_sibling;
+	struct list_head	s_children;
+	void 			* s_element;
+	int			s_type;
+	struct dentry		* s_dentry;
+};
+
+#define SYSFS_ROOT		0x0001
+#define	SYSFS_KOBJECT		0x0002
+#define	SYSFS_KOBJ_ATTR		0x0004
+#define	SYSFS_KOBJ_BIN_ATTR	0x0008
+#define	SYSFS_KOBJ_ATTR_GROUP	0x0010
+
 extern int
 sysfs_create_dir(struct kobject *);
 

diff -puN fs/sysfs/mount.c~sysfs-leaves-mount fs/sysfs/mount.c
@@ -20,6 +20,14 @@ struct super_block * sysfs_sb = NULL;
 static struct super_operations sysfs_ops = {
 	.statfs		= simple_statfs,
 	.drop_inode	= generic_delete_inode,
+	.umount_begin 	= sysfs_umount_begin,
+};
+
+struct sysfs_dirent sysfs_root = {
+	.s_sibling	= LIST_HEAD_INIT(sysfs_root.s_sibling),
+	.s_children	= LIST_HEAD_INIT(sysfs_root.s_children),
+	.s_element	= NULL,
+	.s_type		= SYSFS_ROOT,
 };
 
 static int sysfs_fill_super(struct super_block *sb, void *data, int silent)

@@ -35,8 +43,8 @@ static int sysfs_fill_super(struct super
 
 	inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
 	if (inode) {
-		inode->i_op = &simple_dir_inode_operations;
-		inode->i_fop = &simple_dir_operations;
+		inode->i_op = &sysfs_dir_inode_operations;
+		inode->i_fop = &sysfs_dir_operations;
 		/* directory inodes start off with i_nlink == 2 (for "." entry) */
 		inode->i_nlink++;	
 	} else {

@@ -50,6 +58,7 @@ static int sysfs_fill_super(struct super
 		iput(inode);
 		return -ENOMEM;
 	}
+	root->d_fsdata = &sysfs_root;
 	sb->s_root = root;
 	return 0;
 }

@@ -60,6 +69,14 @@ static struct super_block *sysfs_get_sb(
 	return get_sb_single(fs_type, flags, data, sysfs_fill_super);
 }
 
+void sysfs_umount_begin(struct super_block * sb) 
+{
+	lock_super(sb);
+	if (sb->s_root) 
+		shrink_dcache_parent(sb->s_root);
+	unlock_super(sb);
+}
+
 static struct file_system_type sysfs_fs_type = {
 	.name		= "sysfs",
 	.get_sb		= sysfs_get_sb,

diff -puN fs/sysfs/dir.c~sysfs-leaves-dir fs/sysfs/dir.c
@@ -10,10 +10,54 @@
 #include <linux/kobject.h>
 #include "sysfs.h"
 
+struct inode_operations sysfs_dir_inode_operations = {
+	.lookup		= sysfs_lookup,
+};
+
+struct file_operations sysfs_dir_operations = {
+	.open		= dcache_dir_open,
+	.release	= dcache_dir_close,
+	.llseek		= sysfs_dir_lseek,
+	.read		= generic_read_dir,
+	.readdir	= sysfs_readdir,
+};
+
+/* dentry iput only for sysfs leaf dentries */
+static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) 
+{
+	struct sysfs_dirent * sd = dentry->d_fsdata;
+
+	if (sd)
+		sysfs_put(sd);
+	iput(inode);
+}
+
+
+static struct dentry_operations sysfs_dentry_ops = {
+	.d_iput		= sysfs_d_iput,
+};
+
+char * sysfs_get_name(struct sysfs_dirent *sd)
+{
+	if (!sd || !sd->s_element)
+		BUG();
+
+	return (sd->s_type & SYSFS_KOBJ_ATTR) ?
+		((struct attribute *)(sd->s_element))->name :
+		((struct bin_attribute *)(sd->s_element))->attr.name;
+}
+
+static int init_file(struct inode * inode)
+{
+	inode->i_size = PAGE_SIZE;
+	inode->i_fop = &sysfs_file_operations;
+	return 0;
+}
+
 static int init_dir(struct inode * inode)
 {
-	inode->i_op = &simple_dir_inode_operations;
-	inode->i_fop = &simple_dir_operations;
+	inode->i_op = &sysfs_dir_inode_operations;
+	inode->i_fop = &sysfs_dir_operations;
 
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inode->i_nlink++;

@@ -21,6 +65,61 @@ static int init_dir(struct inode * inode
 }
 
 
+/* attaches attribute's sysfs_dirent to the dentry corresponding to the 
+ * attribute file
+ */
+int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
+{
+	struct attribute * attr = NULL;
+	struct bin_attribute * bin_attr = NULL;
+        int (* init) (struct inode *) = NULL;
+	int error = 0;
+
+        if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
+                bin_attr = sd->s_element;
+                attr = &bin_attr->attr;
+        } else {
+                attr = sd->s_element;
+                init = init_file;
+        }
+
+	error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
+	if (error)
+		return error;
+
+        if (bin_attr) {
+		dentry->d_inode->i_size = bin_attr->size;
+		dentry->d_inode->i_fop = &bin_fops;
+	}
+	dentry->d_op = &sysfs_dentry_ops;
+	dentry->d_fsdata = sysfs_get(sd);
+	sd->s_dentry = dentry;
+	d_rehash(dentry);
+
+	return 0;
+}
+
+struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, 
+				struct nameidata *nd)
+{
+	struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
+	struct sysfs_dirent * sd;
+	int err = 0;
+
+	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+		if ((sd->s_type == SYSFS_KOBJ_ATTR) 
+			|| (sd->s_type == SYSFS_KOBJ_BIN_ATTR)) {
+			char * name = sysfs_get_name(sd);
+			if (strcmp(name, dentry->d_name.name))
+				continue;
+			err = sysfs_attach_attr(sd, dentry);
+			break;
+		}
+	}
+
+	return ERR_PTR(err);
+}
+
 static int create_dir(struct kobject * k, struct dentry * p,
 		      const char * n, struct dentry ** d)
 {

@@ -29,12 +128,23 @@ static int create_dir(struct kobject * k
 	down(&p->d_inode->i_sem);
 	*d = sysfs_get_dentry(p,n);
 	if (!IS_ERR(*d)) {
-		error = sysfs_create(*d,
+		error = sysfs_create(*d, 
 					 S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO,
 					 init_dir);
 		if (!error) {
-			(*d)->d_fsdata = k;
-			p->d_inode->i_nlink++;
+			struct sysfs_dirent * sd, * parent_sd;
+			parent_sd = p->d_fsdata;
+			sd = sysfs_new_dirent(parent_sd, k, 
+						(parent_sd->s_element == k) ? 
+						SYSFS_KOBJ_ATTR_GROUP : 
+						SYSFS_KOBJECT);
+			if (sd) {
+				(*d)->d_fsdata = sysfs_get(sd);
+				(*d)->d_op = &sysfs_dentry_ops;
+				p->d_inode->i_nlink++;
+				d_rehash(*d);
+			} else
+				error = -ENOMEM;
 		}
 		dput(*d);
 	} else

@@ -81,9 +191,15 @@ int sysfs_create_dir(struct kobject * ko
 static void remove_dir(struct dentry * d)
 {
 	struct dentry * parent = dget(d->d_parent);
+	struct sysfs_dirent * sd;
+
 	down(&parent->d_inode->i_sem);
 	d_delete(d);
-	simple_rmdir(parent->d_inode,d);
+	sd = d->d_fsdata;
+	list_del_init(&sd->s_sibling);
+	sysfs_put(d->d_fsdata);
+	if (parent->d_inode)
+		simple_rmdir(parent->d_inode,d);
 
 	pr_debug(" o %s removing done (%d)\n",d->d_name.name,
 		 atomic_read(&d->d_count));

@@ -133,9 +249,18 @@ void sysfs_remove_dir(struct kobject * k
 			 * Unlink and unhash.
 			 */
 			spin_unlock(&dcache_lock);
-			d_delete(d);
-			simple_unlink(dentry->d_inode,d);
-			dput(d);
+			if (S_ISREG(d->d_inode->i_mode)) {
+				struct sysfs_dirent * sd = d->d_fsdata;
+
+				list_del_init(&sd->s_sibling);
+				sysfs_put(sd);
+				d_drop(d);
+				simple_unlink(dentry->d_inode,d);
+			} else {
+				d_delete(d);
+				simple_unlink(dentry->d_inode,d);
+				dput(d);
+			}
 			spin_lock(&dcache_lock);
 		}
 		pr_debug(" done\n");

@@ -172,6 +297,164 @@ void sysfs_rename_dir(struct kobject * k
 	up(&parent->d_inode->i_sem);	
 }
 
+/* called under parent inode's i_sem (taken in vfs_readdir */
+static void sysfs_close_attr_files(struct dentry * parent)
+{
+	struct sysfs_dirent * parent_sd = parent->d_fsdata;
+	struct sysfs_dirent * sd;
+
+	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+		if ((sd->s_type == SYSFS_KOBJ_ATTR) || 
+			(sd->s_type == SYSFS_KOBJ_BIN_ATTR)) {
+			struct dentry * dentry = sd->s_dentry;
+			if (dentry && dentry->d_inode)
+				dput(dentry);
+		}
+	}
+}
+
+/* called under parent inode's i_sem (taken in vfs_readdir */
+static int sysfs_open_attr_files(struct dentry * parent)
+{
+	struct sysfs_dirent * parent_sd = parent->d_fsdata;
+	struct sysfs_dirent * sd;
+	struct dentry * dentry;
+	int error = 0;
+
+	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+		if ((sd->s_type == SYSFS_KOBJ_ATTR) || 
+			(sd->s_type == SYSFS_KOBJ_BIN_ATTR)) {
+			char * name = sysfs_get_name(sd);
+			dentry = sysfs_get_dentry(parent, name);
+			if (IS_ERR(dentry))
+				error = PTR_ERR(dentry);
+			if (!dentry->d_inode) 
+				error = sysfs_attach_attr(sd, dentry);
+			if (error)
+				break;
+		}
+	}
+	if (error) {
+		/* release all successfully opened entires so far*/
+		sysfs_close_attr_files(parent);
+	}
+
+	return error;
+}
+
+/* Relationship between i_mode and the DT_xxx types */
+static inline unsigned char dt_type(struct inode *inode)
+{
+	return (inode->i_mode >> 12) & 15;
+}
+
+/*
+ * Directory is locked and all positive dentries in it are safe, since
+ * for ramfs-type trees they can't go away without unlink() or rmdir(),
+ * both impossible due to the lock on directory.
+ */
+
+int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
+{
+	struct dentry *dentry = filp->f_dentry;
+	struct dentry *cursor = filp->private_data;
+	struct list_head *p, *q = &cursor->d_child;
+	ino_t ino;
+	int i = filp->f_pos;
+	int err = 0;
+
+	switch (i) {
+		case 0:
+			ino = dentry->d_inode->i_ino;
+			if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
+				break;
+			filp->f_pos++;
+			i++;
+			/* fallthrough */
+		case 1:
+			ino = parent_ino(dentry);
+			if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
+				break;
+			filp->f_pos++;
+			i++;
+			/* fallthrough */
+		default:
+			if ((err = sysfs_open_attr_files(dentry)))
+				return err;
+	
+			spin_lock(&dcache_lock);
+			if (filp->f_pos == 2) {
+				list_del(q);
+				list_add(q, &dentry->d_subdirs);
+			}
+			for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
+				struct dentry *next;
+				next = list_entry(p, struct dentry, d_child);
+				if (d_unhashed(next) || !next->d_inode)
+					continue;
+
+				spin_unlock(&dcache_lock);
+				if (filldir(dirent, next->d_name.name, next->d_name.len, filp->f_pos, next->d_inode->i_ino, dt_type(next->d_inode)) < 0)
+					return 0;
+				spin_lock(&dcache_lock);
+				/* next is still alive */
+				list_del(q);
+				list_add(q, p);
+				p = q;
+				filp->f_pos++;
+			}
+			spin_unlock(&dcache_lock);
+			sysfs_close_attr_files(dentry);
+	}
+	return 0;
+}
+
+loff_t sysfs_dir_lseek(struct file *file, loff_t offset, int origin)
+{
+	int err = 0;
+
+	down(&file->f_dentry->d_inode->i_sem);
+	switch (origin) {
+		case 1:
+			offset += file->f_pos;
+		case 0:
+			if (offset >= 0)
+				break;
+		default:
+			up(&file->f_dentry->d_inode->i_sem);
+			return -EINVAL;
+	}
+	if (offset != file->f_pos) {
+		file->f_pos = offset;
+		if (file->f_pos >= 2) {
+			struct list_head *p;
+			struct dentry *cursor = file->private_data;
+			loff_t n = file->f_pos - 2;
+
+			if ((err = sysfs_open_attr_files(file->f_dentry))) {
+				offset = err;
+				goto exit;
+			}
+
+			spin_lock(&dcache_lock);
+			list_del(&cursor->d_child);
+			p = file->f_dentry->d_subdirs.next;
+			while (n && p != &file->f_dentry->d_subdirs) {
+				struct dentry *next;
+				next = list_entry(p, struct dentry, d_child);
+				if (!d_unhashed(next) && next->d_inode)
+					n--;
+				p = p->next;
+			}
+			list_add_tail(&cursor->d_child, p);
+			spin_unlock(&dcache_lock);
+			sysfs_close_attr_files(file->f_dentry);
+		}
+	}
+exit:
+	up(&file->f_dentry->d_inode->i_sem);
+	return offset;
+}
 EXPORT_SYMBOL(sysfs_create_dir);
 EXPORT_SYMBOL(sysfs_remove_dir);
 EXPORT_SYMBOL(sysfs_rename_dir);

diff -puN fs/sysfs/file.c~sysfs-leaves-file fs/sysfs/file.c
@@ -9,14 +9,6 @@
 
 #include "sysfs.h"
 
-static struct file_operations sysfs_file_operations;
-
-static int init_file(struct inode * inode)
-{
-	inode->i_size = PAGE_SIZE;
-	inode->i_fop = &sysfs_file_operations;
-	return 0;
-}
 
 #define to_subsys(k) container_of(k,struct subsystem,kset.kobj)
 #define to_sattr(a) container_of(a,struct subsys_attribute,attr)

@@ -77,8 +69,10 @@ struct sysfs_buffer {
  */
 static int fill_read_buffer(struct file * file, struct sysfs_buffer * buffer)
 {
-	struct attribute * attr = file->f_dentry->d_fsdata;
-	struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
+	struct sysfs_dirent * sd_attr = file->f_dentry->d_fsdata;
+	struct attribute * attr = sd_attr->s_element;
+	struct sysfs_dirent * sd_kobj = file->f_dentry->d_parent->d_fsdata;
+	struct kobject * kobj = sd_kobj->s_element;
 	struct sysfs_ops * ops = buffer->ops;
 	int ret = 0;
 	ssize_t count;

@@ -198,8 +192,10 @@ fill_write_buffer(struct sysfs_buffer * 
 static int 
 flush_write_buffer(struct file * file, struct sysfs_buffer * buffer, size_t count)
 {
-	struct attribute * attr = file->f_dentry->d_fsdata;
-	struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
+	struct sysfs_dirent * sd_attr = file->f_dentry->d_fsdata;
+	struct attribute * attr = sd_attr->s_element;
+	struct sysfs_dirent * sd_kobj = file->f_dentry->d_parent->d_fsdata;
+	struct kobject * kobj = sd_kobj->s_element;
 	struct sysfs_ops * ops = buffer->ops;
 
 	return ops->store(kobj,attr,buffer->page,count);

@@ -238,8 +234,10 @@ sysfs_write_file(struct file *file, cons
 
 static int check_perm(struct inode * inode, struct file * file)
 {
-	struct kobject * kobj = kobject_get(file->f_dentry->d_parent->d_fsdata);
-	struct attribute * attr = file->f_dentry->d_fsdata;
+	struct sysfs_dirent * sd_attr = file->f_dentry->d_fsdata;
+	struct attribute * attr = sd_attr->s_element;
+	struct sysfs_dirent * sd_kobj = file->f_dentry->d_parent->d_fsdata;
+	struct kobject * kobj = kobject_get(sd_kobj->s_element);
 	struct sysfs_buffer * buffer;
 	struct sysfs_ops * ops = NULL;
 	int error = 0;

@@ -320,8 +318,10 @@ static int sysfs_open_file(struct inode 
 
 static int sysfs_release(struct inode * inode, struct file * filp)
 {
-	struct kobject * kobj = filp->f_dentry->d_parent->d_fsdata;
-	struct attribute * attr = filp->f_dentry->d_fsdata;
+	struct sysfs_dirent * sd_attr = filp->f_dentry->d_fsdata;
+	struct attribute * attr = sd_attr->s_element;
+	struct sysfs_dirent * sd_kobj = filp->f_dentry->d_parent->d_fsdata;
+	struct kobject * kobj = kobject_get(sd_kobj->s_element);
 	struct sysfs_buffer * buffer = filp->private_data;
 
 	if (kobj) 

@@ -336,7 +336,7 @@ static int sysfs_release(struct inode * 
 	return 0;
 }
 
-static struct file_operations sysfs_file_operations = {
+struct file_operations sysfs_file_operations = {
 	.read		= sysfs_read_file,
 	.write		= sysfs_write_file,
 	.llseek		= generic_file_llseek,

@@ -345,23 +345,18 @@ static struct file_operations sysfs_file
 };
 
 
-int sysfs_add_file(struct dentry * dir, const struct attribute * attr)
+int sysfs_add_file(struct dentry * parent, int t, const struct attribute * attr)
 {
-	struct dentry * dentry;
-	int error;
+	struct sysfs_dirent * sd;
+	struct sysfs_dirent * parent_sd = parent->d_fsdata;
+	int error = 0;
 
-	down(&dir->d_inode->i_sem);
-	dentry = sysfs_get_dentry(dir,attr->name);
-	if (!IS_ERR(dentry)) {
-		error = sysfs_create(dentry,
-				     (attr->mode & S_IALLUGO) | S_IFREG,
-				     init_file);
-		if (!error)
-			dentry->d_fsdata = (void *)attr;
-		dput(dentry);
-	} else
-		error = PTR_ERR(dentry);
-	up(&dir->d_inode->i_sem);
+	down(&parent->d_inode->i_sem);			
+	sd = sysfs_new_dirent(parent_sd, (void *) attr, t);
+	if (!sd)
+		error =  -ENOMEM;
+	up(&parent->d_inode->i_sem);			
+	
 	return error;
 }
 

@@ -374,8 +369,8 @@ int sysfs_add_file(struct dentry * dir, 
 
 int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
 {
-	if (kobj && attr)
-		return sysfs_add_file(kobj->dentry,attr);
+	if (kobj && kobj->dentry && attr) 
+		return sysfs_add_file(kobj->dentry, SYSFS_KOBJ_ATTR, attr);
 	return -EINVAL;
 }
 

diff -puN fs/sysfs/inode.c~sysfs-leaves-file fs/sysfs/inode.c
@@ -11,6 +11,8 @@
 #include <linux/pagemap.h>
 #include <linux/namei.h>
 #include <linux/backing-dev.h>
+#include "sysfs.h"
+
 extern struct super_block * sysfs_sb;
 
 static struct address_space_operations sysfs_aops = {

@@ -61,7 +63,8 @@ int sysfs_create(struct dentry * dentry,
 		error = init(inode);
 	if (!error) {
 		d_instantiate(dentry, inode);
-		dget(dentry); /* Extra count - pin the dentry in core */
+		if (!S_ISREG(inode->i_mode)) 
+			dget(dentry);  /* pin non-leaf dentry in core */
 	} else
 		iput(inode);
  Done:

@@ -96,14 +99,24 @@ void sysfs_hash_and_remove(struct dentry
 			pr_debug("sysfs: Removing %s (%d)\n", victim->d_name.name,
 				 atomic_read(&victim->d_count));
 
-			d_delete(victim);
-			simple_unlink(dir->d_inode,victim);
+			if (S_ISREG(victim->d_inode->i_mode)) {
+				spin_lock(&dcache_lock);
+				spin_lock(&victim->d_lock);
+				__d_drop(victim);
+				spin_unlock(&dcache_lock);
+				spin_unlock(&victim->d_lock);
+			}
+			else {
+				d_delete(victim);
+				simple_unlink(dir->d_inode,victim);
+			}
 		}
 		/*
 		 * Drop reference from sysfs_get_dentry() above.
 		 */
 		dput(victim);
 	}
+	sysfs_remove_attr_dirent(dir->d_fsdata, name);
 	up(&dir->d_inode->i_sem);
 }
 

diff -puN fs/sysfs/bin.c~sysfs-leaves-bin fs/sysfs/bin.c
@@ -17,8 +17,10 @@
 static int
 fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)
 {
-	struct bin_attribute * attr = dentry->d_fsdata;
-	struct kobject * kobj = dentry->d_parent->d_fsdata;
+	struct sysfs_dirent * sd_attr = dentry->d_fsdata;
+	struct bin_attribute * attr = sd_attr->s_element;
+	struct sysfs_dirent * sd_kobj = dentry->d_parent->d_fsdata;
+	struct kobject * kobj = sd_kobj->s_element;
 
 	return attr->read(kobj, buffer, off, count);
 }

@@ -60,8 +62,10 @@ read(struct file * file, char __user * u
 static int
 flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
 {
-	struct bin_attribute *attr = dentry->d_fsdata;
-	struct kobject *kobj = dentry->d_parent->d_fsdata;
+	struct sysfs_dirent * sd_attr = dentry->d_fsdata;
+	struct bin_attribute * attr = sd_attr->s_element;
+	struct sysfs_dirent * sd_kobj = dentry->d_parent->d_fsdata;
+	struct kobject * kobj = sd_kobj->s_element;
 
 	return attr->write(kobj, buffer, offset, count);
 }

@@ -94,8 +98,10 @@ static ssize_t write(struct file * file,
 
 static int open(struct inode * inode, struct file * file)
 {
-	struct kobject * kobj = kobject_get(file->f_dentry->d_parent->d_fsdata);
-	struct bin_attribute * attr = file->f_dentry->d_fsdata;
+	struct sysfs_dirent * sd_kobj = file->f_dentry->d_parent->d_fsdata;
+	struct kobject * kobj = kobject_get(sd_kobj->s_element);
+	struct sysfs_dirent * sd_attr = file->f_dentry->d_fsdata;
+	struct bin_attribute * attr = sd_attr->s_element;
 	int error = -EINVAL;
 
 	if (!kobj || !attr)

@@ -122,7 +128,9 @@ static int open(struct inode * inode, st
 
 static int release(struct inode * inode, struct file * file)
 {
-	struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
+	struct sysfs_dirent * sd = file->f_dentry->d_parent->d_fsdata;
+	struct kobject * kobj = sd->s_element;
+
 	u8 * buffer = file->private_data;
 
 	if (kobj) 

@@ -131,7 +139,7 @@ static int release(struct inode * inode,
 	return 0;
 }
 
-static struct file_operations bin_fops = {
+struct file_operations bin_fops = {
 	.read		= read,
 	.write		= write,
 	.llseek		= generic_file_llseek,

@@ -148,31 +156,10 @@ static struct file_operations bin_fops =
 
 int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 {
-	struct dentry * dentry;
-	struct dentry * parent;
-	int error = 0;
-
-	if (!kobj || !attr)
-		return -EINVAL;
-
-	parent = kobj->dentry;
-
-	down(&parent->d_inode->i_sem);
-	dentry = sysfs_get_dentry(parent,attr->attr.name);
-	if (!IS_ERR(dentry)) {
-		dentry->d_fsdata = (void *)attr;
-		error = sysfs_create(dentry,
-				     (attr->attr.mode & S_IALLUGO) | S_IFREG,
-				     NULL);
-		if (!error) {
-			dentry->d_inode->i_size = attr->size;
-			dentry->d_inode->i_fop = &bin_fops;
-		}
-		dput(dentry);
-	} else
-		error = PTR_ERR(dentry);
-	up(&parent->d_inode->i_sem);
-	return error;
+	if (kobj && kobj->dentry && attr) 
+		return sysfs_add_file(kobj->dentry, SYSFS_KOBJ_BIN_ATTR, 
+					&attr->attr);
+	return -EINVAL;
 }
 
 

diff -puN fs/sysfs/symlink.c~sysfs-leaves-misc fs/sysfs/symlink.c
@@ -25,6 +25,8 @@ static int sysfs_symlink(struct inode * 
 		error = page_symlink(dentry->d_inode, symname, l);
 		if (error)
 			iput(dentry->d_inode);
+		else
+			d_rehash(dentry);
 	}
 	return error;
 }

diff -puN fs/sysfs/group.c~sysfs-leaves-misc fs/sysfs/group.c
@@ -31,7 +31,7 @@ static int create_files(struct dentry * 
 	int error = 0;
 
 	for (attr = grp->attrs; *attr && !error; attr++) {
-		error = sysfs_add_file(dir,*attr);
+		error = sysfs_add_file(dir, SYSFS_KOBJ_ATTR, * attr);
 	}
 	if (error)
 		remove_files(dir,grp);

81 lines not on this page · raw message

diff -puN fs/sysfs/dir.c~sysfs-leaves-dir fs/sysfs/dir.c
@@ -10,10 +10,54 @@
 #include <linux/kobject.h>
 #include "sysfs.h"
 
+struct inode_operations sysfs_dir_inode_operations = {
+	.lookup		= sysfs_lookup,
+};
+
+struct file_operations sysfs_dir_operations = {
+	.open		= dcache_dir_open,
+	.release	= dcache_dir_close,
+	.llseek		= sysfs_dir_lseek,
+	.read		= generic_read_dir,
+	.readdir	= sysfs_readdir,
+};
+
+/* dentry iput only for sysfs leaf dentries */
+static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) 
+{
+	struct sysfs_dirent * sd = dentry->d_fsdata;
+
+	if (sd)
+		sysfs_put(sd);
+	iput(inode);
+}
+
+
+static struct dentry_operations sysfs_dentry_ops = {
+	.d_iput		= sysfs_d_iput,
+};
+
+char * sysfs_get_name(struct sysfs_dirent *sd)
+{
+	if (!sd || !sd->s_element)
+		BUG();
+
+	return (sd->s_type & SYSFS_KOBJ_ATTR) ?
+		((struct attribute *)(sd->s_element))->name :
+		((struct bin_attribute *)(sd->s_element))->attr.name;
+}
+
+static int init_file(struct inode * inode)
+{
+	inode->i_size = PAGE_SIZE;
+	inode->i_fop = &sysfs_file_operations;
+	return 0;
+}
+
 static int init_dir(struct inode * inode)
 {
-	inode->i_op = &simple_dir_inode_operations;
-	inode->i_fop = &simple_dir_operations;
+	inode->i_op = &sysfs_dir_inode_operations;
+	inode->i_fop = &sysfs_dir_operations;
 
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inode->i_nlink++;

@@ -21,6 +65,61 @@ static int init_dir(struct inode * inode
 }
 
 
+/* attaches attribute's sysfs_dirent to the dentry corresponding to the 
+ * attribute file
+ */
+int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
+{
+	struct attribute * attr = NULL;
+	struct bin_attribute * bin_attr = NULL;
+        int (* init) (struct inode *) = NULL;
+	int error = 0;
+
+        if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
+                bin_attr = sd->s_element;
+                attr = &bin_attr->attr;
+        } else {
+                attr = sd->s_element;
+                init = init_file;
+        }
+
+	error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
+	if (error)
+		return error;
+
+        if (bin_attr) {
+		dentry->d_inode->i_size = bin_attr->size;
+		dentry->d_inode->i_fop = &bin_fops;
+	}
+	dentry->d_op = &sysfs_dentry_ops;
+	dentry->d_fsdata = sysfs_get(sd);
+	sd->s_dentry = dentry;
+	d_rehash(dentry);
+
+	return 0;
+}
+
+struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, 
+				struct nameidata *nd)
+{
+	struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
+	struct sysfs_dirent * sd;
+	int err = 0;
+
+	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+		if ((sd->s_type == SYSFS_KOBJ_ATTR) 
+			|| (sd->s_type == SYSFS_KOBJ_BIN_ATTR)) {
+			char * name = sysfs_get_name(sd);
+			if (strcmp(name, dentry->d_name.name))
+				continue;
+			err = sysfs_attach_attr(sd, dentry);
+			break;
+		}
+	}
+
+	return ERR_PTR(err);
+}
+
 static int create_dir(struct kobject * k, struct dentry * p,
 		      const char * n, struct dentry ** d)
 {

@@ -29,12 +128,23 @@ static int create_dir(struct kobject * k
 	down(&p->d_inode->i_sem);
 	*d = sysfs_get_dentry(p,n);
 	if (!IS_ERR(*d)) {
-		error = sysfs_create(*d,
+		error = sysfs_create(*d, 
 					 S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO,
 					 init_dir);
 		if (!error) {
-			(*d)->d_fsdata = k;
-			p->d_inode->i_nlink++;
+			struct sysfs_dirent * sd, * parent_sd;
+			parent_sd = p->d_fsdata;
+			sd = sysfs_new_dirent(parent_sd, k, 
+						(parent_sd->s_element == k) ? 
+						SYSFS_KOBJ_ATTR_GROUP : 
+						SYSFS_KOBJECT);
+			if (sd) {
+				(*d)->d_fsdata = sysfs_get(sd);
+				(*d)->d_op = &sysfs_dentry_ops;
+				p->d_inode->i_nlink++;
+				d_rehash(*d);
+			} else
+				error = -ENOMEM;
 		}
 		dput(*d);
 	} else

@@ -81,9 +191,15 @@ int sysfs_create_dir(struct kobject * ko
 static void remove_dir(struct dentry * d)
 {
 	struct dentry * parent = dget(d->d_parent);
+	struct sysfs_dirent * sd;
+
 	down(&parent->d_inode->i_sem);
 	d_delete(d);
-	simple_rmdir(parent->d_inode,d);
+	sd = d->d_fsdata;
+	list_del_init(&sd->s_sibling);
+	sysfs_put(d->d_fsdata);
+	if (d->d_inode)
+		simple_rmdir(parent->d_inode,d);
 
 	pr_debug(" o %s removing done (%d)\n",d->d_name.name,
 		 atomic_read(&d->d_count));

@@ -133,9 +249,18 @@ void sysfs_remove_dir(struct kobject * k
 			 * Unlink and unhash.
 			 */
 			spin_unlock(&dcache_lock);
-			d_delete(d);
-			simple_unlink(dentry->d_inode,d);
-			dput(d);
+			if (S_ISREG(d->d_inode->i_mode)) {
+				struct sysfs_dirent * sd = d->d_fsdata;
+
+				list_del_init(&sd->s_sibling);
+				sysfs_put(sd);
+				d_drop(d);
+				simple_unlink(dentry->d_inode,d);
+			} else {
+				d_delete(d);
+				simple_unlink(dentry->d_inode,d);
+				dput(d);
+			}
 			spin_lock(&dcache_lock);
 		}
 		pr_debug(" done\n");

@@ -172,6 +297,164 @@ void sysfs_rename_dir(struct kobject * k
 	up(&parent->d_inode->i_sem);	
 }
 
+/* called under parent inode's i_sem (taken in vfs_readdir */
+static void sysfs_close_attr_files(struct dentry * parent)
+{
+	struct sysfs_dirent * parent_sd = parent->d_fsdata;
+	struct sysfs_dirent * sd;
+
+	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+		if ((sd->s_type == SYSFS_KOBJ_ATTR) || 
+			(sd->s_type == SYSFS_KOBJ_BIN_ATTR)) {
+			struct dentry * dentry = sd->s_dentry;
+			if (dentry && dentry->d_inode)
+				dput(dentry);
+		}
+	}
+}
+
+/* called under parent inode's i_sem (taken in vfs_readdir */
+static int sysfs_open_attr_files(struct dentry * parent)
+{
+	struct sysfs_dirent * parent_sd = parent->d_fsdata;
+	struct sysfs_dirent * sd;
+	struct dentry * dentry;
+	int error = 0;
+
+	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+		if ((sd->s_type == SYSFS_KOBJ_ATTR) || 
+			(sd->s_type == SYSFS_KOBJ_BIN_ATTR)) {
+			char * name = sysfs_get_name(sd);
+			dentry = sysfs_get_dentry(parent, name);
+			if (IS_ERR(dentry))
+				error = PTR_ERR(dentry);
+			if (!dentry->d_inode) 
+				error = sysfs_attach_attr(sd, dentry);
+			if (error)
+				break;
+		}
+	}
+	if (error) {
+		/* release all successfully opened entires so far*/
+		sysfs_close_attr_files(parent);
+	}
+
+	return error;
+}
+
+/* Relationship between i_mode and the DT_xxx types */
+static inline unsigned char dt_type(struct inode *inode)
+{
+	return (inode->i_mode >> 12) & 15;
+}
+
+/*
+ * Directory is locked and all positive dentries in it are safe, since
+ * for ramfs-type trees they can't go away without unlink() or rmdir(),
+ * both impossible due to the lock on directory.
+ */
+
+int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
+{
+	struct dentry *dentry = filp->f_dentry;
+	struct dentry *cursor = filp->private_data;
+	struct list_head *p, *q = &cursor->d_child;
+	ino_t ino;
+	int i = filp->f_pos;
+	int err = 0;
+
+	switch (i) {
+		case 0:
+			ino = dentry->d_inode->i_ino;
+			if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
+				break;
+			filp->f_pos++;
+			i++;
+			/* fallthrough */
+		case 1:
+			ino = parent_ino(dentry);
+			if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
+				break;
+			filp->f_pos++;
+			i++;
+			/* fallthrough */
+		default:
+			if ((err = sysfs_open_attr_files(dentry)))
+				return err;
+	
+			spin_lock(&dcache_lock);
+			if (filp->f_pos == 2) {
+				list_del(q);
+				list_add(q, &dentry->d_subdirs);
+			}
+			for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
+				struct dentry *next;
+				next = list_entry(p, struct dentry, d_child);
+				if (d_unhashed(next) || !next->d_inode)
+					continue;
+
+				spin_unlock(&dcache_lock);
+				if (filldir(dirent, next->d_name.name, next->d_name.len, filp->f_pos, next->d_inode->i_ino, dt_type(next->d_inode)) < 0)
+					return 0;
+				spin_lock(&dcache_lock);
+				/* next is still alive */
+				list_del(q);
+				list_add(q, p);
+				p = q;
+				filp->f_pos++;
+			}
+			spin_unlock(&dcache_lock);
+			sysfs_close_attr_files(dentry);
+	}
+	return 0;
+}
+
+loff_t sysfs_dir_lseek(struct file *file, loff_t offset, int origin)
+{
+	int err = 0;
+
+	down(&file->f_dentry->d_inode->i_sem);
+	switch (origin) {
+		case 1:
+			offset += file->f_pos;
+		case 0:
+			if (offset >= 0)
+				break;
+		default:
+			up(&file->f_dentry->d_inode->i_sem);
+			return -EINVAL;
+	}
+	if (offset != file->f_pos) {
+		file->f_pos = offset;
+		if (file->f_pos >= 2) {
+			struct list_head *p;
+			struct dentry *cursor = file->private_data;
+			loff_t n = file->f_pos - 2;
+
+			if ((err = sysfs_open_attr_files(file->f_dentry))) {
+				offset = err;
+				goto exit;
+			}
+
+			spin_lock(&dcache_lock);
+			list_del(&cursor->d_child);
+			p = file->f_dentry->d_subdirs.next;
+			while (n && p != &file->f_dentry->d_subdirs) {
+				struct dentry *next;
+				next = list_entry(p, struct dentry, d_child);
+				if (!d_unhashed(next) && next->d_inode)
+					n--;
+				p = p->next;
+			}
+			list_add_tail(&cursor->d_child, p);
+			spin_unlock(&dcache_lock);
+			sysfs_close_attr_files(file->f_dentry);
+		}
+	}
+exit:
+	up(&file->f_dentry->d_inode->i_sem);
+	return offset;
+}
 EXPORT_SYMBOL(sysfs_create_dir);
 EXPORT_SYMBOL(sysfs_remove_dir);
 EXPORT_SYMBOL(sysfs_rename_dir);