[2/4] linux-user: Add support for two btrfs ioctls used for subvolume

Commit Message

Filip Bozuta July 17, 2020, 2:04 p.m. UTC

This patch implements functionality for following ioctl:

BTRFS_IOC_DEFAULT_SUBVOL - Setting a default subvolume

    Set a default subvolume for a btrfs filesystem. The third
    ioctl's argument is a '__u64' (unsigned long long) which
    represents the id of a subvolume that is to be set as
    the default.

BTRFS_IOC_GET_SUBVOL_ROOTREF - Getting tree and directory id of subvolumes

    Read tree and directory id of subvolumes from a btrfs
    filesystem. The tree and directory id's are returned in the
    ioctl's third argument which represents a pointer to a
    following type:

    struct btrfs_ioctl_get_subvol_rootref_args {
		/* in/out, minimum id of rootref's treeid to be searched */
		__u64 min_treeid;

		/* out */
		struct {
			__u64 treeid;
			__u64 dirid;
		} rootref[BTRFS_MAX_ROOTREF_BUFFER_NUM];

		/* out, number of found items */
		__u8 num_items;
		__u8 align[7];
     };

     Before calling this ioctl, 'min_treeid' field should be filled
     with value that represent the minimum value for the tree id.

Implementation notes:

    Ioctl BTRFS_IOC_GET_SUBVOL_ROOTREF uses the above mentioned structure
    type as third argument. That is the reason why a aproppriate thunk
    structure definition is added in file 'syscall_types.h'.
---
 linux-user/ioctls.h        |  7 +++++++
 linux-user/syscall_defs.h  |  4 ++++
 linux-user/syscall_types.h | 11 +++++++++++
 3 files changed, 22 insertions(+)

Patch

diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
index a7f5664487..2c553103e6 100644
--- a/linux-user/ioctls.h
+++ b/linux-user/ioctls.h
@@ -206,6 +206,9 @@ 
      IOCTL(BTRFS_IOC_INO_LOOKUP, IOC_RW,
            MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_ino_lookup_args)))
 #endif
+#ifdef BTRFS_IOC_DEFAULT_SUBVOL
+     IOCTL(BTRFS_IOC_DEFAULT_SUBVOL, IOC_W, MK_PTR(TYPE_ULONGLONG))
+#endif
 #ifdef BTRFS_IOC_SUBVOL_GETFLAGS
      IOCTL(BTRFS_IOC_SUBVOL_GETFLAGS, IOC_R, MK_PTR(TYPE_ULONGLONG))
 #endif
@@ -248,6 +251,10 @@ 
      IOCTL(BTRFS_IOC_GET_SUBVOL_INFO, IOC_R,
            MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_get_subvol_info_args)))
 #endif
+#ifdef BTRFS_IOC_GET_SUBVOL_ROOTREF
+     IOCTL(BTRFS_IOC_GET_SUBVOL_ROOTREF, IOC_RW,
+           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_get_subvol_rootref_args)))
+#endif
 #ifdef BTRFS_IOC_INO_LOOKUP_USER
      IOCTL(BTRFS_IOC_INO_LOOKUP_USER, IOC_RW,
            MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_ino_lookup_user_args)))
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 7bb105428b..f4b4fc4a20 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -984,6 +984,8 @@  struct target_rtc_pll_info {
                                                15, struct btrfs_ioctl_vol_args)
 #define TARGET_BTRFS_IOC_INO_LOOKUP             TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
                                         18, struct btrfs_ioctl_ino_lookup_args)
+#define TARGET_BTRFS_IOC_DEFAULT_SUBVOL         TARGET_IOW(BTRFS_IOCTL_MAGIC, \
+                                                           19, abi_ullong)
 #define TARGET_BTRFS_IOC_SUBVOL_GETFLAGS        TARGET_IOR(BTRFS_IOCTL_MAGIC, \
                                                            25, abi_ullong)
 #define TARGET_BTRFS_IOC_SUBVOL_SETFLAGS        TARGET_IOW(BTRFS_IOCTL_MAGIC, \
@@ -1006,6 +1008,8 @@  struct target_rtc_pll_info {
                                        59, struct btrfs_ioctl_logical_ino_args)
 #define TARGET_BTRFS_IOC_GET_SUBVOL_INFO        TARGET_IOR(BTRFS_IOCTL_MAGIC, \
                                    60, struct btrfs_ioctl_get_subvol_info_args)
+#define TARGET_BTRFS_IOC_GET_SUBVOL_ROOTREF     TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
+                                61, struct btrfs_ioctl_get_subvol_rootref_args)
 #define TARGET_BTRFS_IOC_INO_LOOKUP_USER        TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
                                    62, struct btrfs_ioctl_ino_lookup_user_args)
 
diff --git a/linux-user/syscall_types.h b/linux-user/syscall_types.h
index 980c29000a..d2f1b30ff3 100644
--- a/linux-user/syscall_types.h
+++ b/linux-user/syscall_types.h
@@ -381,6 +381,17 @@  STRUCT(btrfs_ioctl_dev_info_args,
        MK_ARRAY(TYPE_ULONGLONG, 379), /* unused */
        MK_ARRAY(TYPE_CHAR, BTRFS_DEVICE_PATH_NAME_MAX)) /* path */
 
+STRUCT(rootref,
+       TYPE_ULONGLONG, /* treeid */
+       TYPE_ULONGLONG) /* dirid */
+
+STRUCT(btrfs_ioctl_get_subvol_rootref_args,
+    TYPE_ULONGLONG, /* min_treeid */
+    MK_ARRAY(MK_STRUCT(STRUCT_rootref),
+             BTRFS_MAX_ROOTREF_BUFFER_NUM), /* rootref */
+    TYPE_CHAR, /* num_items */
+    MK_ARRAY(TYPE_CHAR, 7)) /* align */
+
 STRUCT(btrfs_ioctl_get_dev_stats,
        TYPE_ULONGLONG, /* devid */
        TYPE_ULONGLONG, /* nr_items */