From: Nick Piggin <npiggin@kernel.dk>
Date: Fri, 7 Jan 2011 06:50:01 +0000 (+1100)
Subject: btrfs: provide simple rcu-walk ACL implementation
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=258a5aa8dfc6294f5f7df892023ee4d3e57c9841;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

btrfs: provide simple rcu-walk ACL implementation

This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
---

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index cb518a4b917c..6ae2c8cac9d5 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -187,18 +187,21 @@ static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
 
 int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags)
 {
-	struct posix_acl *acl;
 	int error = -EAGAIN;
 
-	if (flags & IPERM_FLAG_RCU)
-		return -ECHILD;
+	if (flags & IPERM_FLAG_RCU) {
+		if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
+			error = -ECHILD;
 
-	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
-	if (IS_ERR(acl))
-		return PTR_ERR(acl);
-	if (acl) {
-		error = posix_acl_permission(inode, acl, mask);
-		posix_acl_release(acl);
+	} else {
+		struct posix_acl *acl;
+		acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		if (acl) {
+			error = posix_acl_permission(inode, acl, mask);
+			posix_acl_release(acl);
+		}
 	}
 
 	return error;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5cf0db0081f9..a0ff46a47895 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7213,9 +7213,6 @@ static int btrfs_set_page_dirty(struct page *page)
 
 static int btrfs_permission(struct inode *inode, int mask, unsigned int flags)
 {
-	if (flags & IPERM_FLAG_RCU)
-		return -ECHILD;
-
 	if ((BTRFS_I(inode)->flags & BTRFS_INODE_READONLY) && (mask & MAY_WRITE))
 		return -EACCES;
 	return generic_permission(inode, mask, flags, btrfs_check_acl);