This adds a writeable attribute which describes the label.
Signed-off-by: Jeff Mahoney <je...@suse.com>
---
fs/btrfs/sysfs.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
--- a/fs/btrfs/sysfs.c 2013-10-21 16:20:06.395804741 -0400
+++ b/fs/btrfs/sysfs.c 2013-10-21 16:23:57.402255196 -0400
@@ -355,6 +355,49 @@ static const struct attribute *allocatio
NULL,
};
+static ssize_t btrfs_label_show(struct kobject *kobj,
+ struct kobj_attribute *a, char *buf)
+{
+ struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+ return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label);
+}
+
+static ssize_t btrfs_label_store(struct kobject *kobj,
+ struct kobj_attribute *a,
+ const char *buf, size_t len)
+{
+ struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *root = fs_info->fs_root;
+ int ret;
+
+ if (len >= BTRFS_LABEL_SIZE) {
+ pr_err("btrfs: unable to set label with more than %d bytes\n",
+ BTRFS_LABEL_SIZE - 1);
+ return -EINVAL;
+ }
+
+ trans = btrfs_start_transaction(root, 0);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ spin_lock(&root->fs_info->super_lock);
+ strcpy(fs_info->super_copy->label, buf);
+ spin_unlock(&root->fs_info->super_lock);
+ ret = btrfs_commit_transaction(trans, root);
+
+ if (!ret)
+ return len;
+
+ return ret;
+}
+BTRFS_ATTR_RW(label, 0644, btrfs_label_show, btrfs_label_store);
+
+static struct attribute *btrfs_attrs[] = {
+ BTRFS_ATTR_PTR(label),
+ NULL,
+};
+
static void btrfs_release_super_kobj(struct kobject *kobj)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
@@ -364,6 +407,7 @@ static void btrfs_release_super_kobj(str
static struct kobj_type btrfs_ktype = {
.sysfs_ops = &kobj_sysfs_ops,
.release = btrfs_release_super_kobj,
+ .default_attrs = btrfs_attrs,
};
static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
--
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