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authorLi Zefan <lizf@cn.fujitsu.com>2010-12-20 16:30:25 +0800
committerLi Zefan <lizf@cn.fujitsu.com>2010-12-23 08:49:19 +0800
commit0caa102da82799efaba88e234484786a9591c797 (patch)
tree748bb0d8054bb85256904ffe29913277e5b80684 /fs/btrfs
parentb83cc9693f39689490970c19f6c5b866f6719a70 (diff)
Btrfs: Add BTRFS_IOC_SUBVOL_GETFLAGS/SETFLAGS ioctls
This allows us to set a snapshot or a subvolume readonly or writable on the fly. Usage: Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and then call ioctl(BTRFS_IOCTL_SUBVOL_SETFLAGS); Changelog for v3: - Change to pass __u64 as ioctl parameter. Changelog for v2: - Add _GETFLAGS ioctl. - Check if the passed fd is the root of a subvolume. - Change the name from _SNAP_SETFLAGS to _SUBVOL_SETFLAGS. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/ioctl.c83
-rw-r--r--fs/btrfs/ioctl.h2
2 files changed, 85 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f066ccb5ddd..ad1983524f9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1009,6 +1009,85 @@ out:
return ret;
}
+static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
+ void __user *arg)
+{
+ struct inode *inode = fdentry(file)->d_inode;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ int ret = 0;
+ u64 flags = 0;
+
+ if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID)
+ return -EINVAL;
+
+ down_read(&root->fs_info->subvol_sem);
+ if (btrfs_root_readonly(root))
+ flags |= BTRFS_SUBVOL_RDONLY;
+ up_read(&root->fs_info->subvol_sem);
+
+ if (copy_to_user(arg, &flags, sizeof(flags)))
+ ret = -EFAULT;
+
+ return ret;
+}
+
+static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
+ void __user *arg)
+{
+ struct inode *inode = fdentry(file)->d_inode;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_trans_handle *trans;
+ u64 root_flags;
+ u64 flags;
+ int ret = 0;
+
+ if (root->fs_info->sb->s_flags & MS_RDONLY)
+ return -EROFS;
+
+ if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID)
+ return -EINVAL;
+
+ if (copy_from_user(&flags, arg, sizeof(flags)))
+ return -EFAULT;
+
+ if (flags & ~BTRFS_SUBVOL_CREATE_ASYNC)
+ return -EINVAL;
+
+ if (flags & ~BTRFS_SUBVOL_RDONLY)
+ return -EOPNOTSUPP;
+
+ down_write(&root->fs_info->subvol_sem);
+
+ /* nothing to do */
+ if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
+ goto out;
+
+ root_flags = btrfs_root_flags(&root->root_item);
+ if (flags & BTRFS_SUBVOL_RDONLY)
+ btrfs_set_root_flags(&root->root_item,
+ root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
+ else
+ btrfs_set_root_flags(&root->root_item,
+ root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
+
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out_reset;
+ }
+
+ ret = btrfs_update_root(trans, root,
+ &root->root_key, &root->root_item);
+
+ btrfs_commit_transaction(trans, root);
+out_reset:
+ if (ret)
+ btrfs_set_root_flags(&root->root_item, root_flags);
+out:
+ up_write(&root->fs_info->subvol_sem);
+ return ret;
+}
+
/*
* helper to check if the subvolume references other subvolumes
*/
@@ -2282,6 +2361,10 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_snap_create(file, argp, 1);
case BTRFS_IOC_SNAP_DESTROY:
return btrfs_ioctl_snap_destroy(file, argp);
+ case BTRFS_IOC_SUBVOL_GETFLAGS:
+ return btrfs_ioctl_subvol_getflags(file, argp);
+ case BTRFS_IOC_SUBVOL_SETFLAGS:
+ return btrfs_ioctl_subvol_setflags(file, argp);
case BTRFS_IOC_DEFAULT_SUBVOL:
return btrfs_ioctl_default_subvol(file, argp);
case BTRFS_IOC_DEFRAG:
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 52ae489974b..1223223351f 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -194,4 +194,6 @@ struct btrfs_ioctl_space_args {
#define BTRFS_IOC_WAIT_SYNC _IOW(BTRFS_IOCTL_MAGIC, 22, __u64)
#define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \
struct btrfs_ioctl_vol_args_v2)
+#define BTRFS_IOC_SUBVOL_GETFLAGS _IOW(BTRFS_IOCTL_MAGIC, 25, __u64)
+#define BTRFS_IOC_SUBVOL_SETFLAGS _IOW(BTRFS_IOCTL_MAGIC, 26, __u64)
#endif