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Commit 04256b4a authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Greg Kroah-Hartman
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sysfs: reference sysfs_dirent from sysfs inodes 



The sysfs_dirent serves as both an inode and a directory entry
for sysfs.  To prevent the sysfs inode numbers from being freed
prematurely hold a reference to sysfs_dirent from the sysfs inode.

[akpm@linux-foundation.org: add comment]
Signed-off-by: default avatarEric W. Biederman <ebiederm@aristanetworks.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 425cb029

fs/sysfs/inode.c

+17 −0
Original line number Diff line number Diff line
@@ -147,6 +147,7 @@ static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode) 
{

	struct bin_attribute *bin_attr;



	inode->i_private = sysfs_get(sd);

	inode->i_mapping->a_ops = &sysfs_aops;

	inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;

	inode->i_op = &sysfs_inode_operations;
@@ -214,6 +215,22 @@ struct inode * sysfs_get_inode(struct sysfs_dirent *sd) 
	return inode;

}



/*

 * The sysfs_dirent serves as both an inode and a directory entry for sysfs.

 * To prevent the sysfs inode numbers from being freed prematurely we take a

 * reference to sysfs_dirent from the sysfs inode.  A

 * super_operations.delete_inode() implementation is needed to drop that

 * reference upon inode destruction.

 */

void sysfs_delete_inode(struct inode *inode)

{

	struct sysfs_dirent *sd  = inode->i_private;



	truncate_inode_pages(&inode->i_data, 0);

	clear_inode(inode);

	sysfs_put(sd);

}



int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)

{

	struct sysfs_addrm_cxt acxt;

fs/sysfs/mount.c

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ struct kmem_cache *sysfs_dir_cachep; 
static const struct super_operations sysfs_ops = {

	.statfs		= simple_statfs,

	.drop_inode	= generic_delete_inode,

	.delete_inode	= sysfs_delete_inode,

};



struct sysfs_dirent sysfs_root = {

fs/sysfs/sysfs.h

+1 −0
Original line number Diff line number Diff line
@@ -145,6 +145,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd) 
 * inode.c

 */

struct inode *sysfs_get_inode(struct sysfs_dirent *sd);

void sysfs_delete_inode(struct inode *inode);

int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);

int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);

int sysfs_inode_init(void);