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>

1 files changed, 24 insertions, 6 deletions

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;