[PATCH -V1 01/22] vfs: Add generic IS_ACL() test for acl support

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

From: Andreas Gruenbacher <agruen@kernel.org>

When IS_POSIXACL() is true, the vfs does not apply the umask.  Other acl
models will need the same exception, so introduce a separate IS_ACL()
test.

The IS_POSIX_ACL() test is still needed so that nfsd can determine when
the underlying file system supports POSIX ACLs (as opposed to some other
kind).

Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/namei.c              | 8 ++++----
 include/linux/fs.h      | 6 ++++++
 include/uapi/linux/fs.h | 2 +-
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index c6157c894fce..c7fee619691f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2650,7 +2650,7 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
 	}
 
 	mode = op->mode;
-	if ((open_flag & O_CREAT) && !IS_POSIXACL(dir))
+	if ((open_flag & O_CREAT) && !IS_ACL(dir))
 		mode &= ~current_umask();
 
 	excl = (open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT);
@@ -2834,7 +2834,7 @@ static int lookup_open(struct nameidata *nd, struct path *path,
 	/* Negative dentry, just create the file */
 	if (!dentry->d_inode && (op->open_flag & O_CREAT)) {
 		umode_t mode = op->mode;
-		if (!IS_POSIXACL(dir->d_inode))
+		if (!IS_ACL(dir->d_inode))
 			mode &= ~current_umask();
 		/*
 		 * This write is needed to ensure that a
@@ -3422,7 +3422,7 @@ retry:
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
 
-	if (!IS_POSIXACL(path.dentry->d_inode))
+	if (!IS_ACL(path.dentry->d_inode))
 		mode &= ~current_umask();
 	error = security_path_mknod(&path, dentry, mode, dev);
 	if (error)
@@ -3491,7 +3491,7 @@ retry:
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
 
-	if (!IS_POSIXACL(path.dentry->d_inode))
+	if (!IS_ACL(path.dentry->d_inode))
 		mode &= ~current_umask();
 	error = security_path_mkdir(&path, dentry, mode);
 	if (!error)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7a9c5bca2b76..9fb63b71a014 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1611,6 +1611,12 @@ struct super_operations {
 #define IS_NOSEC(inode)		((inode)->i_flags & S_NOSEC)
 
 /*
+ * IS_ACL() tells the VFS to not apply the umask
+ * and use check_acl for acl permission checks when defined.
+ */
+#define IS_ACL(inode)		__IS_FLG(inode, MS_POSIXACL)
+
+/*
  * Inode state bits.  Protected by inode->i_lock
  *
  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index ca1a11bb4443..1e14b9c82703 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -80,7 +80,7 @@ struct inodes_stat_t {
 #define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
 				   MS_VERBOSE is deprecated. */
 #define MS_SILENT	32768
-#define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
+#define MS_POSIXACL	(1<<16)	/* Supports POSIX ACLs */
 #define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
 #define MS_PRIVATE	(1<<18)	/* change to private */
 #define MS_SLAVE	(1<<19)	/* change to slave */
-- 
1.9.1