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Commit 83f714f9 authored by Daniel Rosenberg's avatar Daniel Rosenberg
Browse files

ANDROID: sdcardfs: Fix locking issue with permision fix up 



Don't use lookup_one_len so we can grab the spinlock that
protects d_subdirs.

Bug: 30954918
Change-Id: I0c6a393252db7beb467e0d563739a3a14e1b5115
Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
parent 6eb8f1f5

fs/sdcardfs/derived_perm.c

+15 −21
Original line number Diff line number Diff line
@@ -141,32 +141,26 @@ void fixup_perms_recursive(struct dentry *dentry, const char* name, size_t len) 
	info = SDCARDFS_I(d_inode(dentry));



	if (needs_fixup(info->perm)) {

		/* We need permission to fix up these values.

		 * Since permissions are based of of the mount, and

		 * we are accessing without the mount point, we create

		 * a fake mount with the permissions we will be using.

		 */

		struct vfsmount fakemnt;

		struct sdcardfs_vfsmount_options opts;

		fakemnt.data = &opts;

		opts.gid = AID_SDCARD_RW;

		opts.mask = 0;

		mutex_lock(&d_inode(dentry)->i_mutex);

		child = lookup_one_len2(name, &fakemnt, dentry, len);

		mutex_unlock(&d_inode(dentry)->i_mutex);

		if (!IS_ERR(child)) {

			if (d_inode(child)) {

		spin_lock(&dentry->d_lock);

		list_for_each_entry(child, &dentry->d_subdirs, d_child) {

				dget(child);

				if (!strncasecmp(child->d_name.name, name, len)) {

					if (child->d_inode) {

						get_derived_permission(dentry, child);

				fixup_tmp_permissions(d_inode(child));

						fixup_tmp_permissions(child->d_inode);

						dput(child);

						break;

					}

				}

				dput(child);

		}

		spin_unlock(&dentry->d_lock);

	} else 	if (descendant_may_need_fixup(info->perm)) {

		mutex_lock(&d_inode(dentry)->i_mutex);

		spin_lock(&dentry->d_lock);

		list_for_each_entry(child, &dentry->d_subdirs, d_child) {

				fixup_perms_recursive(child, name, len);

		}

		mutex_unlock(&d_inode(dentry)->i_mutex);

		spin_unlock(&dentry->d_lock);

	}

	dput(dentry);

}