Add a new ioctl BTRFS_FS_SETLABEL to change the label of a mounted filesystem.
Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx>
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
fs/btrfs/ioctl.c | 14 ++++++++++++++
fs/btrfs/ioctl.h | 2 ++
2 files changed, 16 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 8fcf9a5..b0a5e17 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3699,6 +3699,18 @@ out:
return ret;
}
+static int btrfs_ioctl_get_fslabel(struct btrfs_root *root, void __user *arg)
+{
+ const char *label = root->fs_info->super_copy->label;
+ int ret;
+
+ mutex_lock(&root->fs_info->volume_mutex);
+ ret = copy_to_user(arg, label, strlen(label));
+ mutex_unlock(&root->fs_info->volume_mutex);
+
+ return ret ? -EFAULT : 0;
+}
+
long btrfs_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
{
@@ -3797,6 +3809,8 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_qgroup_create(root, argp);
case BTRFS_IOC_QGROUP_LIMIT:
return btrfs_ioctl_qgroup_limit(root, argp);
+ case BTRFS_IOC_GET_FSLABEL:
+ return btrfs_ioctl_get_fslabel(root, argp);
}
return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 731e287..98f896f 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -453,4 +453,6 @@ struct btrfs_ioctl_send_args {
struct btrfs_ioctl_qgroup_limit_args)
#define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \
struct btrfs_ioctl_get_dev_stats)
+#define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 53, \
+ char[BTRFS_LABEL_SIZE])
#endif
--
1.7.9.5
jeff@koala:/usr/src/linux$ cat btrfs_label_v3/0002-set-label.patch
Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx>
---
fs/btrfs/ioctl.c | 34 ++++++++++++++++++++++++++++++++++
fs/btrfs/ioctl.h | 2 ++
2 files changed, 36 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b0a5e17..ebbf634 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3711,6 +3711,38 @@ static int btrfs_ioctl_get_fslabel(struct btrfs_root *root, void __user *arg)
return ret ? -EFAULT : 0;
}
+static int btrfs_ioctl_set_fslabel(struct btrfs_root *root, void __user *arg)
+{
+ struct btrfs_super_block *super_block = root->fs_info->super_copy;
+ struct btrfs_trans_handle *trans;
+ char label[BTRFS_LABEL_SIZE];
+ int ret = 0;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (btrfs_root_readonly(root))
+ return -EROFS;
+
+ if (copy_from_user(label, arg, sizeof(label)))
+ return -EFAULT;
+
+ label[BTRFS_LABEL_SIZE - 1] = '\0';
+
+ mutex_lock(&root->fs_info->volume_mutex);
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out_unlock;
+ }
+ strcpy(super_block->label, label);
+ btrfs_end_transaction(trans, root);
+
+out_unlock:
+ mutex_unlock(&root->fs_info->volume_mutex);
+ return ret;
+}
+
long btrfs_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
{
@@ -3811,6 +3843,8 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_qgroup_limit(root, argp);
case BTRFS_IOC_GET_FSLABEL:
return btrfs_ioctl_get_fslabel(root, argp);
+ case BTRFS_IOC_SET_FSLABEL:
+ return btrfs_ioctl_set_fslabel(root, argp);
}
return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 98f896f..cc4e657 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -455,4 +455,6 @@ struct btrfs_ioctl_send_args {
struct btrfs_ioctl_get_dev_stats)
#define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 53, \
char[BTRFS_LABEL_SIZE])
+#define BTRFS_IOC_SET_FSLABEL _IOW(BTRFS_IOCTL_MAGIC, 54, \
+ char[BTRFS_LABEL_SIZE])
#endif
--
1.7.9.5
--
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