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Commit c74eb981 authored by Al Viro's avatar Al Viro Committed by Sasha Levin
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debugfs: leave freeing a symlink body until inode eviction 



commit 0db59e59299f0b67450c5db21f7f316c8fb04e84 upstream.

As it is, we have debugfs_remove() racing with symlink traversals.
Supply ->evict_inode() and do freeing there - inode will remain
pinned until we are done with the symlink body.

And rip the idiocy with checking if dentry is positive right after
we'd verified debugfs_positive(), which is a stronger check...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent be9eb995

fs/debugfs/inode.c

+17 −17
Original line number Diff line number Diff line
@@ -246,10 +246,19 @@ static int debugfs_show_options(struct seq_file *m, struct dentry *root) 
	return 0;

}



static void debugfs_evict_inode(struct inode *inode)

{

	truncate_inode_pages_final(&inode->i_data);

	clear_inode(inode);

	if (S_ISLNK(inode->i_mode))

		kfree(inode->i_private);

}



static const struct super_operations debugfs_super_operations = {

	.statfs		= simple_statfs,

	.remount_fs	= debugfs_remount,

	.show_options	= debugfs_show_options,

	.evict_inode	= debugfs_evict_inode,

};



static int debug_fill_super(struct super_block *sb, void *data, int silent)
@@ -466,24 +475,15 @@ static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) 
	int ret = 0;



	if (debugfs_positive(dentry)) {

		if (dentry->d_inode) {

		dget(dentry);

			switch (dentry->d_inode->i_mode & S_IFMT) {

			case S_IFDIR:

		if (S_ISDIR(dentry->d_inode->i_mode))

			ret = simple_rmdir(parent->d_inode, dentry);

				break;

			case S_IFLNK:

				kfree(dentry->d_inode->i_private);

				/* fall through */

			default:

		else

			simple_unlink(parent->d_inode, dentry);

				break;

			}

		if (!ret)

			d_delete(dentry);

		dput(dentry);

	}

	}

	return ret;

}