From: Daniel Rosenberg <drosen@google.com>
Date: Wed, 19 Apr 2017 05:25:15 +0000 (-0700)
Subject: ANDROID: sdcardfs: Don't do d_add for lower fs
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b81400914c3989bafc3d3683348acbb5ac57dbdc;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

ANDROID: sdcardfs: Don't do d_add for lower fs

For file based encryption, ext4 explicitly does not
create negative dentries for encrypted files. If you
force one over it, the decrypted file will be hidden
until the cache is cleared. Instead, just fail out.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 37231161
Change-Id: Id2a9708dfa75e1c22f89915c529789caadd2ca4b
---

diff --git a/fs/sdcardfs/lookup.c b/fs/sdcardfs/lookup.c
index 19154b77b0fc..126e233654fe 100644
--- a/fs/sdcardfs/lookup.c
+++ b/fs/sdcardfs/lookup.c
@@ -368,17 +368,15 @@ put_name:
 	dname.len = name->len;
 	dname.hash = full_name_hash(lower_dir_dentry, dname.name, dname.len);
 	lower_dentry = d_lookup(lower_dir_dentry, &dname);
-	if (lower_dentry)
-		goto setup_lower;
-
-	lower_dentry = d_alloc(lower_dir_dentry, &dname);
 	if (!lower_dentry) {
-		err = -ENOMEM;
+		/* We called vfs_path_lookup earlier, and did not get a negative
+		 * dentry then. Don't confuse the lower filesystem by forcing
+		 * one on it now...
+		 */
+		err = -ENOENT;
 		goto out;
 	}
-	d_add(lower_dentry, NULL); /* instantiate and hash */
 
-setup_lower:
 	lower_path.dentry = lower_dentry;
 	lower_path.mnt = mntget(lower_dir_mnt);
 	sdcardfs_set_lower_path(dentry, &lower_path);