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Commit d0bcb568 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
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sysfs: make sysfs_drop_dentry() access inodes using ilookup() 



sysfs_drop_dentry() used to go through sd->s_dentry and
sd->s_parent->s_dentry to access the inodes.  This is incorrect
because inode can be cached without dentry.

This patch makes sysfs_drop_dentry() access inodes using ilookup() on
sd->s_ino.  This is both correct and simpler.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 9d9307da

fs/sysfs/inode.c

+28 −35
Original line number Diff line number Diff line
@@ -219,9 +219,9 @@ void sysfs_instantiate(struct dentry *dentry, struct inode *inode) 
 */

void sysfs_drop_dentry(struct sysfs_dirent *sd)

{

	struct dentry *dentry = NULL, *parent = NULL;

	struct inode *dir;

	struct dentry *dentry = NULL;

	struct timespec curtime;

	struct inode *inode;



	/* We're not holding a reference to ->s_dentry dentry but the

	 * field will stay valid as long as sysfs_lock is held.
@@ -229,19 +229,9 @@ void sysfs_drop_dentry(struct sysfs_dirent *sd) 
	spin_lock(&sysfs_lock);

	spin_lock(&dcache_lock);



	/* drop dentry if it's there and dput() didn't kill it yet */

	if (sd->s_dentry && sd->s_dentry->d_inode) {

		/* get dentry if it's there and dput() didn't kill it yet */

		dentry = dget_locked(sd->s_dentry);

		parent = dentry->d_parent;

	} else if (sd->s_parent->s_dentry->d_inode) {

		/* We need to update the parent even if dentry for the

		 * victim itself doesn't exist.

		 */

		parent = dget_locked(sd->s_parent->s_dentry);

	}



	/* drop */

	if (dentry) {

		spin_lock(&dentry->d_lock);

		__d_drop(dentry);

		spin_unlock(&dentry->d_lock);
@@ -250,36 +240,39 @@ void sysfs_drop_dentry(struct sysfs_dirent *sd) 
	spin_unlock(&dcache_lock);

	spin_unlock(&sysfs_lock);



	/* nothing to do if the parent isn't in dcache */

	if (!parent)

		return;

	dput(dentry);

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

	if (sd->s_type & SYSFS_DIR)

		dput(dentry);



	/* adjust nlink and update timestamp */

	dir = parent->d_inode;

	mutex_lock(&dir->i_mutex);



	curtime = CURRENT_TIME;



	dir->i_ctime = dir->i_mtime = curtime;

	inode = ilookup(sysfs_sb, sd->s_ino);

	if (inode) {

		mutex_lock(&inode->i_mutex);



	if (dentry) {

		dentry->d_inode->i_ctime = curtime;

		drop_nlink(dentry->d_inode);

		if (sd->s_type & SYSFS_DIR) {

			drop_nlink(dentry->d_inode);

			drop_nlink(dir);

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

			dput(dentry);

		}

		inode->i_ctime = curtime;

		drop_nlink(inode);

		if (sd->s_type & SYSFS_DIR)

			drop_nlink(inode);



		mutex_unlock(&inode->i_mutex);

		iput(inode);

	}



	mutex_unlock(&dir->i_mutex);

	/* adjust nlink and udpate timestamp of the parent */

	inode = ilookup(sysfs_sb, sd->s_parent->s_ino);

	if (inode) {

		mutex_lock(&inode->i_mutex);



	/* bye bye */

	if (dentry)

		dput(dentry);

	else

		dput(parent);

		inode->i_ctime = inode->i_mtime = curtime;

		if (sd->s_type & SYSFS_DIR)

			drop_nlink(inode);



		mutex_unlock(&inode->i_mutex);

		iput(inode);

	}

}



int sysfs_hash_and_remove(struct dentry * dir, const char * name)