Hello,
I'd like to introduce a new ioctl to set file system label.
With this feature, we can execute `btrfs filesystem label [label]
[path]` through btrfs tools to set or change the label.
Signed-off-by: Jie Liu <jeff....@oracle.com>
---
fs/btrfs/ctree.h | 6 ++++++
fs/btrfs/ioctl.c | 37 +++++++++++++++++++++++++++++++++++++
fs/btrfs/ioctl.h | 2 ++
3 files changed, 45 insertions(+), 0 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 03912c5..2889b5e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1259,6 +1259,12 @@ struct btrfs_ioctl_defrag_range_args {
};
+struct btrfs_ioctl_fs_label_args {
+ /* label length in bytes */
+ __u32 len;
+ char label[BTRFS_LABEL_SIZE];
+};
+
/*
* inode items have the data typically returned from stat and store other
* info about object characteristics. There is one for every file and
dir in
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 970977a..9e01628 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -268,6 +268,41 @@ static int btrfs_ioctl_getversion(struct file
*file, int __user *arg)
return put_user(inode->i_generation, arg);
}
+static int btrfs_ioctl_fs_setlabel(struct btrfs_root *root, void __user
*arg)
+{
+ struct btrfs_super_block *super_block = &(root->fs_info->super_copy);
+ struct btrfs_ioctl_fs_label_args *label_args;
+ struct btrfs_trans_handle *trans;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (btrfs_root_readonly(root))
+ return -EROFS;
+
+ label_args = memdup_user(arg, sizeof(*label_args));
+ if (IS_ERR(label_args))
+ return PTR_ERR(label_args);
+
+ if (label_args->len >= sizeof(label_args->label))
+ return -EINVAL;
+
+ mutex_lock(&root->fs_info->volume_mutex);
+ trans = btrfs_start_transaction(root, 0);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ if (snprintf(super_block->label, BTRFS_LABEL_SIZE, "%s",
+ label_args->label) != label_args->len)
+ return -EFAULT;
+
+ btrfs_end_transaction(trans, root);
+ mutex_unlock(&root->fs_info->volume_mutex);
+
+ kfree(label_args);
+ return 0;
+}
+
static noinline int btrfs_ioctl_fitrim(struct file *file, void __user
*arg)
{
struct btrfs_root *root = fdentry(file)->d_sb->s_fs_info;
@@ -2876,6 +2911,8 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_fs_info(root, argp);
case BTRFS_IOC_DEV_INFO:
return btrfs_ioctl_dev_info(root, argp);
+ case BTRFS_IOC_FS_SETLABEL:
+ return btrfs_ioctl_fs_setlabel(root, argp);
case BTRFS_IOC_BALANCE:
return btrfs_balance(root->fs_info->dev_root);
case BTRFS_IOC_CLONE:
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index ad1ea78..1e0ca2a 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -248,4 +248,6 @@ struct btrfs_ioctl_space_args {
struct btrfs_ioctl_dev_info_args)
#define BTRFS_IOC_FS_INFO _IOR(BTRFS_IOCTL_MAGIC, 31, \
struct btrfs_ioctl_fs_info_args)
+#define BTRFS_IOC_FS_SETLABEL _IOW(BTRFS_IOCTL_MAGIC, 32, \
+ struct btrfs_ioctl_fs_label_args)
#endif
--
1.7.4.1
--
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