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Commit 0335dee5 authored by Daniel Rosenberg's avatar Daniel Rosenberg
Browse files

ANDROID: sdcardfs: Replace get/put with d_lock 



dput cannot be called with a spin_lock. Instead,
we protect our accesses by holding the d_lock.

Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
Bug: 35643557
Change-Id: I22cf30856d75b5616cbb0c223724f5ab866b5114
parent dd146a75

fs/sdcardfs/derived_perm.c

+20 −13
Original line number Diff line number Diff line
@@ -264,41 +264,48 @@ static int needs_fixup(perm_t perm) { 
	return 0;

}



void fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit)

static void __fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit, int depth)

{

	struct dentry *child;

	struct sdcardfs_inode_info *info;

	if (!dget(dentry))

		return;



	/*

	 * All paths will terminate their recursion on hitting PERM_ANDROID_OBB,

	 * PERM_ANDROID_MEDIA, or PERM_ANDROID_DATA. This happens at a depth of

	 * at most 3.

	 */

	WARN(depth > 3, "%s: Max expected depth exceeded!\n", __func__);

	spin_lock_nested(&dentry->d_lock, depth);

	if (!d_inode(dentry)) {

		dput(dentry);

		spin_unlock(&dentry->d_lock);

		return;

	}

	info = SDCARDFS_I(d_inode(dentry));



	if (needs_fixup(info->perm)) {

		spin_lock(&dentry->d_lock);

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

			dget(child);

			spin_lock_nested(&child->d_lock, depth + 1);

			if (!(limit->flags & BY_NAME) || !strncasecmp(child->d_name.name, limit->name, limit->length)) {

				if (d_inode(child)) {

					get_derived_permission(dentry, child);

					fixup_tmp_permissions(d_inode(child));

					dput(child);

					spin_unlock(&child->d_lock);

					break;

				}

			}

			dput(child);

			spin_unlock(&child->d_lock);

		}

		spin_unlock(&dentry->d_lock);

	} else 	if (descendant_may_need_fixup(info, limit)) {

		spin_lock(&dentry->d_lock);

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

				fixup_perms_recursive(child, limit);

				__fixup_perms_recursive(child, limit, depth + 1);

		}

	}

	spin_unlock(&dentry->d_lock);

}

	dput(dentry);



void fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit)

{

	__fixup_perms_recursive(dentry, limit, 0);

}



void drop_recursive(struct dentry *parent)