[lustre-devel] [PATCH 22/22] ext4: export mb stream allocator variables

[James Simmons <jsimmons@infradead.org>]

Signed-off-by: James Simmons <jsimmons@infradead.org>
---
 fs/ext4/ext4.h    |  2 ++
 fs/ext4/mballoc.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/sysfs.c   |  4 ++++
 3 files changed, 65 insertions(+)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 0ee4606..46f2619 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2620,6 +2620,8 @@ extern int ext4_init_inode_table(struct super_block *sb,
 /* mballoc.c */
 extern const struct file_operations ext4_seq_prealloc_table_fops;
 extern const struct seq_operations ext4_mb_seq_groups_ops;
+extern const struct file_operations ext4_seq_mb_last_group_fops;
+extern int ext4_mb_seq_last_start_seq_show(struct seq_file *m, void *v);
 extern long ext4_mb_stats;
 extern long ext4_mb_max_to_scan;
 extern int ext4_mb_init(struct super_block *);
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 82398b0..8270e35 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2459,6 +2459,65 @@ static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
 	return cachep;
 }
 
+#define EXT4_MB_MAX_INPUT_STRING_SIZE 32
+
+static ssize_t ext4_mb_last_group_write(struct file *file,
+					const char __user *buf,
+					size_t cnt, loff_t *pos)
+{
+	char dummy[EXT4_MB_MAX_INPUT_STRING_SIZE + 1];
+	struct super_block *sb = PDE_DATA(file_inode(file));
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	unsigned long val;
+	char *end;
+
+	if (cnt > EXT4_MB_MAX_INPUT_STRING_SIZE)
+		return -EINVAL;
+	if (copy_from_user(dummy, buf, cnt))
+		return -EFAULT;
+	dummy[cnt] = '\0';
+	val = simple_strtoul(dummy, &end, 0);
+	if (dummy == end)
+		return -EINVAL;
+	if (val >= ext4_get_groups_count(sb))
+		return -ERANGE;
+	spin_lock(&sbi->s_md_lock);
+	sbi->s_mb_last_group = val;
+	sbi->s_mb_last_start = 0;
+	spin_unlock(&sbi->s_md_lock);
+	return cnt;
+}
+
+static int ext4_mb_seq_last_group_seq_show(struct seq_file *m, void *v)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(m->private);
+
+	seq_printf(m , "%ld\n", sbi->s_mb_last_group);
+	return 0;
+}
+
+static int ext4_mb_seq_last_group_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, ext4_mb_seq_last_group_seq_show, PDE_DATA(inode));
+}
+
+const struct file_operations ext4_seq_mb_last_group_fops = {
+	.owner		= THIS_MODULE,
+	.open		= ext4_mb_seq_last_group_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+	.write		= ext4_mb_last_group_write,
+};
+
+int ext4_mb_seq_last_start_seq_show(struct seq_file *m, void *v)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(m->private);
+
+	seq_printf(m , "%ld\n", sbi->s_mb_last_start);
+	return 0;
+}
+
 /*
  * Allocate the top-level s_group_info array for the specified number
  * of groups
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 575f318..6bcb455 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -425,6 +425,10 @@ int ext4_register_sysfs(struct super_block *sb)
 				&ext4_mb_seq_groups_ops, sb);
 		proc_create_data("prealloc_table", S_IRUGO, sbi->s_proc,
 				 &ext4_seq_prealloc_table_fops, sb);
+		proc_create_data("mb_last_group", S_IRUGO, sbi->s_proc,
+				 &ext4_seq_mb_last_group_fops, sb);
+		proc_create_single_data("mb_last_start", S_IRUGO, sbi->s_proc,
+					ext4_mb_seq_last_start_seq_show, sb);
 	}
 	return 0;
 }
-- 
1.8.3.1