f2fs: support hot file extension

This patch supports to recognize hot file extension in f2fs, so that we
can allocate proper hot segment location for its data, which can lead to
better hot/cold seperation in filesystem.

In addition, we changes a bit on query/add/del operation method for
extension_list sysfs entry as below:

- Query: cat /sys/fs/f2fs/<disk>/extension_list
- Add: echo 'extension' > /sys/fs/f2fs/<disk>/extension_list
- Del: echo '!extension' > /sys/fs/f2fs/<disk>/extension_list
- Add: echo '[h/c]extension' > /sys/fs/f2fs/<disk>/extension_list
- Del: echo '[h/c]!extension' > /sys/fs/f2fs/<disk>/extension_list
- [h] means add/del hot file extension
- [c] means add/del cold file extension

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

4 files changed, 90 insertions, 28 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 833c9bc06d03..f6dc70666ebb 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -576,6 +576,7 @@ enum {
 #define FADVISE_ENCRYPT_BIT	0x04
 #define FADVISE_ENC_NAME_BIT	0x08
 #define FADVISE_KEEP_SIZE_BIT	0x10
+#define FADVISE_HOT_BIT		0x20
 
 #define file_is_cold(inode)	is_file(inode, FADVISE_COLD_BIT)
 #define file_wrong_pino(inode)	is_file(inode, FADVISE_LOST_PINO_BIT)
@@ -590,6 +591,9 @@ enum {
 #define file_set_enc_name(inode) set_file(inode, FADVISE_ENC_NAME_BIT)
 #define file_keep_isize(inode)	is_file(inode, FADVISE_KEEP_SIZE_BIT)
 #define file_set_keep_isize(inode) set_file(inode, FADVISE_KEEP_SIZE_BIT)
+#define file_is_hot(inode)	is_file(inode, FADVISE_HOT_BIT)
+#define file_set_hot(inode)	set_file(inode, FADVISE_HOT_BIT)
+#define file_clear_hot(inode)	clear_file(inode, FADVISE_HOT_BIT)
 
 #define DEF_DIR_LEVEL		0
 
@@ -2614,7 +2618,7 @@ void handle_failed_inode(struct inode *inode);
  * namei.c
  */
 int update_extension_list(struct f2fs_sb_info *sbi, const char *name,
-								bool set);
+							bool hot, bool set);
 struct dentry *f2fs_get_parent(struct dentry *child);
 
 /*
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 2bd6e9f5746a..78ea0156f027 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -142,7 +142,7 @@ fail_drop:
 	return ERR_PTR(err);
 }
 
-static int is_multimedia_file(const unsigned char *s, const char *sub)
+static int is_extension_exist(const unsigned char *s, const char *sub)
 {
 	size_t slen = strlen(s);
 	size_t sublen = strlen(sub);
@@ -168,33 +168,59 @@ static int is_multimedia_file(const unsigned char *s, const char *sub)
 /*
  * Set multimedia files as cold files for hot/cold data separation
  */
-static inline void set_cold_files(struct f2fs_sb_info *sbi, struct inode *inode,
+static inline void set_file_temperature(struct f2fs_sb_info *sbi, struct inode *inode,
 		const unsigned char *name)
 {
 	__u8 (*extlist)[F2FS_EXTENSION_LEN] = sbi->raw_super->extension_list;
-	int i, count;
+	int i, cold_count, hot_count;
 
 	down_read(&sbi->sb_lock);
 
-	count = le32_to_cpu(sbi->raw_super->extension_count);
+	cold_count = le32_to_cpu(sbi->raw_super->extension_count);
+	hot_count = sbi->raw_super->hot_ext_count;
 
-	for (i = 0; i < count; i++) {
-		if (is_multimedia_file(name, extlist[i])) {
+	for (i = 0; i < cold_count + hot_count; i++) {
+		if (!is_extension_exist(name, extlist[i]))
+			continue;
+		if (i < cold_count)
 			file_set_cold(inode);
-			break;
-		}
+		else
+			file_set_hot(inode);
+		break;
 	}
 
 	up_read(&sbi->sb_lock);
 }
 
-int update_extension_list(struct f2fs_sb_info *sbi, const char *name, bool set)
+int update_extension_list(struct f2fs_sb_info *sbi, const char *name,
+							bool hot, bool set)
 {
 	__u8 (*extlist)[F2FS_EXTENSION_LEN] = sbi->raw_super->extension_list;
-	int count = le32_to_cpu(sbi->raw_super->extension_count);
+	int cold_count = le32_to_cpu(sbi->raw_super->extension_count);
+	int hot_count = sbi->raw_super->hot_ext_count;
+	int total_count = cold_count + hot_count;
+	int start, count;
 	int i;
 
-	for (i = 0; i < count; i++) {
+	if (set) {
+		if (total_count == F2FS_MAX_EXTENSION)
+			return -EINVAL;
+	} else {
+		if (!hot && !cold_count)
+			return -EINVAL;
+		if (hot && !hot_count)
+			return -EINVAL;
+	}
+
+	if (hot) {
+		start = cold_count;
+		count = total_count;
+	} else {
+		start = 0;
+		count = cold_count;
+	}
+
+	for (i = start; i < count; i++) {
 		if (strcmp(name, extlist[i]))
 			continue;
 
@@ -202,20 +228,33 @@ int update_extension_list(struct f2fs_sb_info *sbi, const char *name, bool set)
 			return -EINVAL;
 
 		memcpy(extlist[i], extlist[i + 1],
-				F2FS_EXTENSION_LEN * (count - i - 1));
-		memset(extlist[count - 1], 0, F2FS_EXTENSION_LEN);
-		sbi->raw_super->extension_count = cpu_to_le32(count - 1);
+				F2FS_EXTENSION_LEN * (total_count - i - 1));
+		memset(extlist[total_count - 1], 0, F2FS_EXTENSION_LEN);
+		if (hot)
+			sbi->raw_super->hot_ext_count = hot_count - 1;
+		else
+			sbi->raw_super->extension_count =
+						cpu_to_le32(cold_count - 1);
 		return 0;
 	}
 
 	if (!set)
 		return -EINVAL;
 
-	if (count == F2FS_MAX_EXTENSION)
-		return -EINVAL;
-
-	strncpy(extlist[count], name, strlen(name));
-	sbi->raw_super->extension_count = cpu_to_le32(count + 1);
+	if (hot) {
+		strncpy(extlist[count], name, strlen(name));
+		sbi->raw_super->hot_ext_count = hot_count + 1;
+	} else {
+		char buf[F2FS_MAX_EXTENSION][F2FS_EXTENSION_LEN];
+
+		memcpy(buf, &extlist[cold_count],
+				F2FS_EXTENSION_LEN * hot_count);
+		memset(extlist[cold_count], 0, F2FS_EXTENSION_LEN);
+		strncpy(extlist[cold_count], name, strlen(name));
+		memcpy(&extlist[cold_count + 1], buf,
+				F2FS_EXTENSION_LEN * hot_count);
+		sbi->raw_super->extension_count = cpu_to_le32(cold_count + 1);
+	}
 	return 0;
 }
 
@@ -239,7 +278,7 @@ static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 		return PTR_ERR(inode);
 
 	if (!test_opt(sbi, DISABLE_EXT_IDENTIFY))
-		set_cold_files(sbi, inode, dentry->d_name.name);
+		set_file_temperature(sbi, inode, dentry->d_name.name);
 
 	inode->i_op = &f2fs_file_inode_operations;
 	inode->i_fop = &f2fs_file_operations;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 1e3dd3de4ecc..f61c77bd673c 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2587,7 +2587,8 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
 
 		if (is_cold_data(fio->page) || file_is_cold(inode))
 			return CURSEG_COLD_DATA;
-		if (is_inode_flag_set(inode, FI_HOT_DATA))
+		if (file_is_hot(inode) ||
+				is_inode_flag_set(inode, FI_HOT_DATA))
 			return CURSEG_HOT_DATA;
 		return rw_hint_to_seg_type(inode->i_write_hint);
 	} else {
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index d27b28e602a6..23a2d8d66c43 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -139,10 +139,19 @@ static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
 	if (!strcmp(a->attr.name, "extension_list")) {
 		__u8 (*extlist)[F2FS_EXTENSION_LEN] =
 					sbi->raw_super->extension_list;
-		int count = le32_to_cpu(sbi->raw_super->extension_count);
+		int cold_count = le32_to_cpu(sbi->raw_super->extension_count);
+		int hot_count = sbi->raw_super->hot_ext_count;
 		int len = 0, i;
 
-		for (i = 0; i < count; i++)
+		len += snprintf(buf + len, PAGE_SIZE - len,
+						"cold file extenstion:\n");
+		for (i = 0; i < cold_count; i++)
+			len += snprintf(buf + len, PAGE_SIZE - len, "%s\n",
+								extlist[i]);
+
+		len += snprintf(buf + len, PAGE_SIZE - len,
+						"hot file extenstion:\n");
+		for (i = cold_count; i < cold_count + hot_count; i++)
 			len += snprintf(buf + len, PAGE_SIZE - len, "%s\n",
 								extlist[i]);
 		return len;
@@ -168,9 +177,18 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
 
 	if (!strcmp(a->attr.name, "extension_list")) {
 		const char *name = strim((char *)buf);
-		bool set = true;
+		bool set = true, hot;
+
+		if (!strncmp(name, "[h]", 3))
+			hot = true;
+		else if (!strncmp(name, "[c]", 3))
+			hot = false;
+		else
+			return -EINVAL;
+
+		name += 3;
 
-		if (name[0] == '!') {
+		if (*name == '!') {
 			name++;
 			set = false;
 		}
@@ -180,13 +198,13 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
 
 		down_write(&sbi->sb_lock);
 
-		ret = update_extension_list(sbi, name, set);
+		ret = update_extension_list(sbi, name, hot, set);
 		if (ret)
 			goto out;
 
 		ret = f2fs_commit_super(sbi, false);
 		if (ret)
-			update_extension_list(sbi, name, !set);
+			update_extension_list(sbi, name, hot, !set);
 out:
 		up_write(&sbi->sb_lock);
 		return ret ? ret : count;