From 52763a4b7a2112743745c5bbfe43fe6f54d4b39a Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Mon, 13 Jun 2016 09:47:48 -0700
Subject: f2fs: detect host-managed SMR by feature flag

If mkfs.f2fs gives a feature flag for host-managed SMR, we can set mode=lfs
by default.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 607ef43..0832528 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -102,7 +102,8 @@ static inline void __submit_bio(struct f2fs_sb_info *sbi, int rw,
 {
 	if (!is_read_io(rw)) {
 		atomic_inc(&sbi->nr_wb_bios);
-		if (current->plug && (type == DATA || type == NODE))
+		if (f2fs_sb_mounted_hmsmr(sbi->sb) &&
+			current->plug && (type == DATA || type == NODE))
 			blk_finish_plug(current->plug);
 	}
 	submit_bio(rw, bio);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index bbcd468..b3aeb58 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -133,6 +133,7 @@ struct f2fs_mount_info {
 };
 
 #define F2FS_FEATURE_ENCRYPT	0x0001
+#define F2FS_FEATURE_HMSMR	0x0002
 
 #define F2FS_HAS_FEATURE(sb, mask)					\
 	((F2FS_SB(sb)->raw_super->feature & cpu_to_le32(mask)) != 0)
@@ -2334,6 +2335,26 @@ static inline int f2fs_sb_has_crypto(struct super_block *sb)
 	return F2FS_HAS_FEATURE(sb, F2FS_FEATURE_ENCRYPT);
 }
 
+static inline int f2fs_sb_mounted_hmsmr(struct super_block *sb)
+{
+	return F2FS_HAS_FEATURE(sb, F2FS_FEATURE_HMSMR);
+}
+
+static inline void set_opt_mode(struct f2fs_sb_info *sbi, unsigned int mt)
+{
+	clear_opt(sbi, ADAPTIVE);
+	clear_opt(sbi, LFS);
+
+	switch (mt) {
+	case F2FS_MOUNT_ADAPTIVE:
+		set_opt(sbi, ADAPTIVE);
+		break;
+	case F2FS_MOUNT_LFS:
+		set_opt(sbi, LFS);
+		break;
+	}
+}
+
 static inline bool f2fs_may_encrypt(struct inode *inode)
 {
 #ifdef CONFIG_F2FS_FS_ENCRYPTION
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 4792f94..782975e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2402,7 +2402,8 @@ int build_segment_manager(struct f2fs_sb_info *sbi)
 	sm_info->ssa_blkaddr = le32_to_cpu(raw_super->ssa_blkaddr);
 	sm_info->rec_prefree_segments = sm_info->main_segments *
 					DEF_RECLAIM_PREFREE_SEGMENTS / 100;
-	sm_info->ipu_policy = 1 << F2FS_IPU_FSYNC;
+	if (!test_opt(sbi, LFS))
+		sm_info->ipu_policy = 1 << F2FS_IPU_FSYNC;
 	sm_info->min_ipu_util = DEF_MIN_IPU_UTIL;
 	sm_info->min_fsync_blocks = DEF_MIN_FSYNC_BLOCKS;
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 41347c0..8c698e1 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -515,12 +515,10 @@ static int parse_options(struct super_block *sb, char *options)
 				return -ENOMEM;
 			if (strlen(name) == 8 &&
 					!strncmp(name, "adaptive", 8)) {
-				set_opt(sbi, ADAPTIVE);
-				clear_opt(sbi, LFS);
+				set_opt_mode(sbi, F2FS_MOUNT_ADAPTIVE);
 			} else if (strlen(name) == 3 &&
 					!strncmp(name, "lfs", 3)) {
-				clear_opt(sbi, ADAPTIVE);
-				set_opt(sbi, LFS);
+				set_opt_mode(sbi, F2FS_MOUNT_LFS);
 			} else {
 				kfree(name);
 				return -EINVAL;
@@ -966,7 +964,12 @@ static void default_options(struct f2fs_sb_info *sbi)
 	set_opt(sbi, EXTENT_CACHE);
 	sbi->sb->s_flags |= MS_LAZYTIME;
 	set_opt(sbi, FLUSH_MERGE);
-	set_opt(sbi, ADAPTIVE);
+	if (f2fs_sb_mounted_hmsmr(sbi->sb)) {
+		set_opt_mode(sbi, F2FS_MOUNT_LFS);
+		set_opt(sbi, DISCARD);
+	} else {
+		set_opt_mode(sbi, F2FS_MOUNT_ADAPTIVE);
+	}
 
 #ifdef CONFIG_F2FS_FS_XATTR
 	set_opt(sbi, XATTR_USER);
@@ -1615,6 +1618,8 @@ try_onemore:
 		goto free_sbi;
 
 	sb->s_fs_info = sbi;
+	sbi->raw_super = raw_super;
+
 	default_options(sbi);
 	/* parse mount options */
 	options = kstrdup((const char *)data, GFP_KERNEL);
@@ -1644,7 +1649,6 @@ try_onemore:
 	memcpy(sb->s_uuid, raw_super->uuid, sizeof(raw_super->uuid));
 
 	/* init f2fs-specific super block info */
-	sbi->raw_super = raw_super;
 	sbi->valid_super_block = valid_super_block;
 	mutex_init(&sbi->gc_mutex);
 	mutex_init(&sbi->cp_mutex);
-- 
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