[PATCH -V1 22/22] ext4: Add Ext4 compat richacl feature flag

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

This feature flag can be used to enable richacl on
the file system. Once enabled the "acl" mount option
will enable richacl instead of posix acl

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/ext4/ext4.h  |  3 ++-
 fs/ext4/super.c | 47 ++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 66946aa62127..17ff4a1cf91e 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -976,7 +976,7 @@ struct ext4_inode_info {
 #define EXT4_MOUNT_UPDATE_JOURNAL	0x01000	/* Update the journal format */
 #define EXT4_MOUNT_NO_UID32		0x02000  /* Disable 32-bit UIDs */
 #define EXT4_MOUNT_XATTR_USER		0x04000	/* Extended user attributes */
-#define EXT4_MOUNT_POSIX_ACL		0x08000	/* POSIX Access Control Lists */
+#define EXT4_MOUNT_ACL			0x08000	/* Access Control Lists */
 #define EXT4_MOUNT_NO_AUTO_DA_ALLOC	0x10000	/* No auto delalloc mapping */
 #define EXT4_MOUNT_BARRIER		0x20000 /* Use block barriers */
 #define EXT4_MOUNT_QUOTA		0x80000 /* Some quota option set */
@@ -1505,6 +1505,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
 #define EXT4_FEATURE_COMPAT_EXT_ATTR		0x0008
 #define EXT4_FEATURE_COMPAT_RESIZE_INODE	0x0010
 #define EXT4_FEATURE_COMPAT_DIR_INDEX		0x0020
+#define EXT4_FEATURE_COMPAT_RICHACL		0x0200
 
 #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
 #define EXT4_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6f9e6fadac04..2a0221652d79 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1274,6 +1274,30 @@ static ext4_fsblk_t get_sb_block(void **data)
 	return sb_block;
 }
 
+static void enable_acl(struct super_block *sb)
+{
+#if !defined(CONFIG_EXT4_FS_POSIX_ACL) && !defined(CONFIG_EXT4_FS_RICHACL)
+	return;
+#endif
+	if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RICHACL)) {
+		sb->s_flags |= MS_RICHACL;
+		sb->s_flags &= ~MS_POSIXACL;
+	} else {
+		sb->s_flags |= MS_POSIXACL;
+		sb->s_flags &= ~MS_RICHACL;
+	}
+	return;
+}
+
+static void disable_acl(struct super_block *sb)
+{
+#if !defined(CONFIG_EXT4_FS_POSIX_ACL) && !defined(CONFIG_EXT4_FS_RICHACL)
+	return;
+#endif
+	sb->s_flags &= ~(MS_POSIXACL | MS_RICHACL);
+	return;
+}
+
 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
@@ -1417,9 +1441,9 @@ static const struct mount_opts {
 	 MOPT_NO_EXT2 | MOPT_DATAJ},
 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
-	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
-	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
+#if defined(CONFIG_EXT4_FS_POSIX_ACL) || defined(CONFIG_EXT4_FS_RICHACL)
+	{Opt_acl, EXT4_MOUNT_ACL, MOPT_SET},
+	{Opt_noacl, EXT4_MOUNT_ACL, MOPT_CLEAR},
 #else
 	{Opt_acl, 0, MOPT_NOSUPPORT},
 	{Opt_noacl, 0, MOPT_NOSUPPORT},
@@ -3496,8 +3520,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		set_opt(sb, NO_UID32);
 	/* xattr user namespace & acls are now defaulted on */
 	set_opt(sb, XATTR_USER);
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
-	set_opt(sb, POSIX_ACL);
+#if defined(CONFIG_EXT4_FS_POSIX_ACL) || defined(CONFIG_EXT4_FS_RICHACL)
+	set_opt(sb, ACL);
 #endif
 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
 		set_opt(sb, JOURNAL_DATA);
@@ -3569,8 +3593,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 			clear_opt(sb, DELALLOC);
 	}
 
-	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
-		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
+	/*
+	 * clear ACL flags
+	 */
+	disable_acl(sb);
+	if (test_opt(sb, ACL))
+		enable_acl(sb);
 
 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
@@ -4844,8 +4872,9 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
 		ext4_abort(sb, "Abort forced by user");
 
-	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
-		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
+	disable_acl(sb);
+	if (test_opt(sb, ACL))
+		enable_acl(sb);
 
 	es = sbi->s_es;
 
-- 
1.9.1