[PATCH v2 2/3] btrfs: sysfs, add readmirror kobject

[Anand Jain <anand.jain@oracle.com>]

Add

 /sys/fs/btrfs/UUID/readmirror

kobject so that we can add readmirror policies as attributes under it.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
v2: Fix compile error fs_info::readmirror_kobj member not found. As its
    fix in v1 went into patch 3/3 instead it should be here.
    
 fs/btrfs/sysfs.c   | 22 ++++++++++++++++++++++
 fs/btrfs/volumes.h |  1 +
 2 files changed, 23 insertions(+)

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index d414b98fb27f..e604f292b42b 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -355,6 +355,10 @@ static ssize_t supported_checksums_show(struct kobject *kobj,
 
 #endif
 
+static const struct attribute *btrfs_readmirror_attrs[] = {
+	NULL,
+};
+
 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 {
 	u64 val;
@@ -772,6 +776,13 @@ void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 {
 	btrfs_reset_fs_info_ptr(fs_info);
 
+	if (fs_info->fs_devices->readmirror_kobj) {
+		sysfs_remove_files(fs_info->fs_devices->readmirror_kobj,
+				   btrfs_readmirror_attrs);
+		kobject_del(fs_info->fs_devices->readmirror_kobj);
+		kobject_put(fs_info->fs_devices->readmirror_kobj);
+	}
+
 	if (fs_info->space_info_kobj) {
 		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 		kobject_del(fs_info->space_info_kobj);
@@ -1224,6 +1235,17 @@ int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 	if (error)
 		goto failure;
 
+	fs_devs->readmirror_kobj = kobject_create_and_add("readmirror",
+							  &fs_devs->fsid_kobj);
+	if (!fs_devs->readmirror_kobj) {
+		error = -ENOMEM;
+		goto failure;
+	}
+	error = sysfs_create_files(fs_devs->readmirror_kobj,
+				   btrfs_readmirror_attrs);
+	if (error)
+		goto failure;
+
 	return 0;
 failure:
 	btrfs_sysfs_remove_mounted(fs_info);
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index f5f091f3c72b..b49afa1cfdd7 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -268,6 +268,7 @@ struct btrfs_fs_devices {
 	struct completion kobj_unregister;
 
 	u8 readmirror;
+	struct kobject *readmirror_kobj;
 };
 
 #define BTRFS_BIO_INLINE_CSUM_SIZE	64
-- 
1.8.3.1