ext4, vfs: add huge= mount option

The same four values as in tmpfs case.

Encyption code is not yet ready to handle huge page, so we disable huge
pages support if the inode has EXT4_INODE_ENCRYPT.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index aff204f..fb3f818 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1133,6 +1133,11 @@
 #define EXT4_MOUNT_DIOREAD_NOLOCK	0x400000 /* Enable support for dio read nolocking */
 #define EXT4_MOUNT_JOURNAL_CHECKSUM	0x800000 /* Journal checksums */
 #define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT	0x1000000 /* Journal Async Commit */
+#define EXT4_MOUNT_HUGE_MODE		0x6000000 /* Huge support mode: */
+#define EXT4_MOUNT_HUGE_NEVER		0x0000000
+#define EXT4_MOUNT_HUGE_ALWAYS		0x2000000
+#define EXT4_MOUNT_HUGE_WITHIN_SIZE	0x4000000
+#define EXT4_MOUNT_HUGE_ADVISE		0x6000000
 #define EXT4_MOUNT_DELALLOC		0x8000000 /* Delalloc support */
 #define EXT4_MOUNT_DATA_ERR_ABORT	0x10000000 /* Abort on file data write */
 #define EXT4_MOUNT_BLOCK_VALIDITY	0x20000000 /* Block validity checking */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 17a767c..4c37fd9 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4472,7 +4472,7 @@
 void ext4_set_inode_flags(struct inode *inode)
 {
 	unsigned int flags = EXT4_I(inode)->i_flags;
-	unsigned int new_fl = 0;
+	unsigned int mask, new_fl = 0;
 
 	if (flags & EXT4_SYNC_FL)
 		new_fl |= S_SYNC;
@@ -4484,12 +4484,28 @@
 		new_fl |= S_NOATIME;
 	if (flags & EXT4_DIRSYNC_FL)
 		new_fl |= S_DIRSYNC;
-	if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode) &&
-	    !ext4_should_journal_data(inode) && !ext4_has_inline_data(inode) &&
-	    !ext4_encrypted_inode(inode))
-		new_fl |= S_DAX;
-	inode_set_flags(inode, new_fl,
-			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX);
+	if (S_ISREG(inode->i_mode) && !ext4_encrypted_inode(inode)) {
+		if (test_opt(inode->i_sb, DAX) &&
+				!ext4_should_journal_data(inode) &&
+				!ext4_has_inline_data(inode))
+			new_fl |= S_DAX;
+		switch (test_opt(inode->i_sb, HUGE_MODE)) {
+		case EXT4_MOUNT_HUGE_NEVER:
+			break;
+		case EXT4_MOUNT_HUGE_ALWAYS:
+			new_fl |= S_HUGE_ALWAYS;
+			break;
+		case EXT4_MOUNT_HUGE_WITHIN_SIZE:
+			new_fl |= S_HUGE_WITHIN_SIZE;
+			break;
+		case EXT4_MOUNT_HUGE_ADVISE:
+			new_fl |= S_HUGE_ADVISE;
+			break;
+		}
+	}
+	mask = S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
+		S_DIRSYNC | S_DAX | S_HUGE_MODE;
+	inode_set_flags(inode, new_fl, mask);
 }
 
 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 72b459d..127ddfe 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1296,6 +1296,7 @@
 	Opt_dioread_nolock, Opt_dioread_lock,
 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
 	Opt_max_dir_size_kb, Opt_nojournal_checksum,
+	Opt_huge_never, Opt_huge_always, Opt_huge_within_size, Opt_huge_advise,
 };
 
 static const match_table_t tokens = {
@@ -1376,6 +1377,10 @@
 	{Opt_init_itable, "init_itable"},
 	{Opt_noinit_itable, "noinit_itable"},
 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
+	{Opt_huge_never, "huge=never"},
+	{Opt_huge_always, "huge=always"},
+	{Opt_huge_within_size, "huge=within_size"},
+	{Opt_huge_advise, "huge=advise"},
 	{Opt_test_dummy_encryption, "test_dummy_encryption"},
 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
@@ -1494,6 +1499,11 @@
 #define MOPT_NO_EXT3	0x0200
 #define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
 #define MOPT_STRING	0x0400
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+#define MOPT_HUGE	0x1000
+#else
+#define MOPT_HUGE	MOPT_NOSUPPORT
+#endif
 
 static const struct mount_opts {
 	int	token;
@@ -1581,6 +1591,10 @@
 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
 	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
+	{Opt_huge_never, EXT4_MOUNT_HUGE_NEVER, MOPT_HUGE},
+	{Opt_huge_always, EXT4_MOUNT_HUGE_ALWAYS, MOPT_HUGE},
+	{Opt_huge_within_size, EXT4_MOUNT_HUGE_WITHIN_SIZE, MOPT_HUGE},
+	{Opt_huge_advise, EXT4_MOUNT_HUGE_ADVISE, MOPT_HUGE},
 	{Opt_test_dummy_encryption, 0, MOPT_GTE0},
 	{Opt_err, 0, 0}
 };
@@ -1662,6 +1676,16 @@
 		} else
 			return -1;
 	}
+	if (MOPT_HUGE != MOPT_NOSUPPORT && m->flags & MOPT_HUGE) {
+		sbi->s_mount_opt &= ~EXT4_MOUNT_HUGE_MODE;
+		sbi->s_mount_opt |= m->mount_opt;
+		if (m->mount_opt) {
+			ext4_msg(sb, KERN_WARNING, "Warning: "
+					"Support of huge pages is EXPERIMENTAL,"
+					" use at your own risk");
+		}
+		return 1;
+	}
 	if (m->flags & MOPT_CLEAR_ERR)
 		clear_opt(sb, ERRORS_MASK);
 	if (token == Opt_noquota && sb_any_quota_loaded(sb)) {