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Commit 35df63c4 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Greg Kroah-Hartman
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sysfs: Fix locking and factor out sysfs_sd_setattr 



Cleanly separate the work that is specific to setting the
attributes of a sysfs_dirent from what is needed to update
the attributes of a vfs inode.

Additionally grab the sysfs_mutex to keep any nasties from
surprising us when updating the sysfs_dirent.

Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarEric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 4be3df28

fs/sysfs/inode.c

+31 −20
Original line number Diff line number Diff line
@@ -65,30 +65,14 @@ static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd) 
	return attrs;

}



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

int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr)

{

	struct inode * inode = dentry->d_inode;

	struct sysfs_dirent * sd = dentry->d_fsdata;

	struct sysfs_inode_attrs *sd_attrs;

	struct iattr *iattrs;

	unsigned int ia_valid = iattr->ia_valid;

	int error;



	if (!sd)

		return -EINVAL;



	sd_attrs = sd->s_iattr;



	error = inode_change_ok(inode, iattr);

	if (error)

		return error;



	iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */



	error = inode_setattr(inode, iattr);

	if (error)

		return error;



	if (!sd_attrs) {

		/* setting attributes for the first time, allocate now */

		sd_attrs = sysfs_init_inode_attrs(sd);
@@ -111,12 +95,39 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) 
			iattrs->ia_ctime = iattr->ia_ctime;

		if (ia_valid & ATTR_MODE) {

			umode_t mode = iattr->ia_mode;



			if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))

				mode &= ~S_ISGID;

			iattrs->ia_mode = sd->s_mode = mode;

		}

	}

	return 0;

}



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

{

	struct inode *inode = dentry->d_inode;

	struct sysfs_dirent *sd = dentry->d_fsdata;

	int error;



	if (!sd)

		return -EINVAL;



	error = inode_change_ok(inode, iattr);

	if (error)

		return error;



	iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */

	if (iattr->ia_valid & ATTR_MODE) {

		if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))

			iattr->ia_mode &= ~S_ISGID;

	}



	error = inode_setattr(inode, iattr);

	if (error)

		return error;



	mutex_lock(&sysfs_mutex);

	error = sysfs_sd_setattr(sd, iattr);

	mutex_unlock(&sysfs_mutex);



	return error;

}

fs/sysfs/sysfs.h

+1 −0
Original line number Diff line number Diff line
@@ -155,6 +155,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd) 
 */

struct inode *sysfs_get_inode(struct sysfs_dirent *sd);

void sysfs_delete_inode(struct inode *inode);

int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr *iattr);

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

int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,

		size_t size, int flags);