1 /* 2 * Functions to convert BTRFS structures from disk to CPU endianness and back. 3 * 4 * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz 5 * 6 * SPDX-License-Identifier: GPL-2.0+ 7 */ 8 9 #ifndef __BTRFS_CONV_FUNCS_H__ 10 #define __BTRFS_CONV_FUNCS_H__ 11 12 #include "ctree.h" 13 #include <u-boot/variadic-macro.h> 14 #include <asm/byteorder.h> 15 16 /* We are using variadic macros and C11 _Generic to achieve compact code. 17 18 We want to define macro DEFINE_CONV(x, ...), where the first argument is the 19 name of the structure for which it shall define conversion functions (the 20 names of the functions shall be x_to_cpu and x_to_disk), and the other 21 arguments are names of the members on which the functions shall do 22 endianness conversion. */ 23 24 #if defined(__LITTLE_ENDIAN) 25 26 /* If the target machine is little endian, the conversion functions do 27 nothing, since the on disk format is little endian. */ 28 29 # define DEFINE_CONV(n,...) \ 30 static inline struct n *n##_to_disk(struct n * r) \ 31 { \ 32 return r; \ 33 } \ 34 static inline struct n *n##_to_cpu(struct n * r) \ 35 { \ 36 return r; \ 37 } 38 39 # define DEFINE_CONV_ALT(n,a,...) \ 40 static inline struct n *n##_to_disk_##a(struct n * r) \ 41 { \ 42 return r; \ 43 } \ 44 static inline struct n *n##_to_cpu_##a(struct n * r) \ 45 { \ 46 return r; \ 47 } 48 49 #else /* !defined(__LITTLE_ENDIAN) */ 50 51 /* Some structures contain not only scalar members, but compound types as well 52 (for example, struct btrfs_inode_item contains members of type struct 53 btrfs_timespec. 54 55 For these members we want to call the conversion function recursively, so 56 first we declare the functions taking pointers to this types (these function 57 will be defined later by the DEFINE_CONV macro) and then we define 58 correspond functions taking non-pointers, so that they can be used in the 59 expansion of the _Generic. */ 60 # define DEFINE_CONV_FOR_STRUCT(n) \ 61 static inline struct n * n##_to_disk(struct n *); \ 62 static inline struct n * n##_to_cpu(struct n *); \ 63 static inline struct n n##_to_disk_v(struct n x) { \ 64 return *n##_to_disk(&x); \ 65 } \ 66 static inline struct n n##_to_cpu_v(struct n x) { \ 67 return *n##_to_cpu(&x); \ 68 } 69 70 DEFINE_CONV_FOR_STRUCT(btrfs_key) 71 DEFINE_CONV_FOR_STRUCT(btrfs_stripe) 72 DEFINE_CONV_FOR_STRUCT(btrfs_timespec) 73 DEFINE_CONV_FOR_STRUCT(btrfs_inode_item) 74 DEFINE_CONV_FOR_STRUCT(btrfs_root_backup) 75 DEFINE_CONV_FOR_STRUCT(btrfs_dev_item) 76 77 /* Now define the _Generic for both CPU to LE and LE to CPU */ 78 # define DEFINE_CONV_CPU_TO_LE(x) \ 79 (d->x) = _Generic((d->x), \ 80 __u16: cpu_to_le16, \ 81 __u32: cpu_to_le32, \ 82 __u64: cpu_to_le64, \ 83 struct btrfs_key: btrfs_key_to_disk_v, \ 84 struct btrfs_stripe: btrfs_stripe_to_disk_v, \ 85 struct btrfs_timespec: btrfs_timespec_to_disk_v, \ 86 struct btrfs_inode_item: btrfs_inode_item_to_disk_v, \ 87 struct btrfs_root_backup: btrfs_root_backup_to_disk_v, \ 88 struct btrfs_dev_item: btrfs_dev_item_to_disk_v \ 89 )((d->x)); 90 91 # define DEFINE_CONV_LE_TO_CPU(x) \ 92 (d->x) = _Generic((d->x), \ 93 __u16: le16_to_cpu, \ 94 __u32: le32_to_cpu, \ 95 __u64: le64_to_cpu, \ 96 struct btrfs_key: btrfs_key_to_cpu_v, \ 97 struct btrfs_stripe: btrfs_stripe_to_cpu_v, \ 98 struct btrfs_timespec: btrfs_timespec_to_cpu_v, \ 99 struct btrfs_inode_item: btrfs_inode_item_to_cpu_v, \ 100 struct btrfs_root_backup: btrfs_root_backup_to_cpu_v, \ 101 struct btrfs_dev_item: btrfs_dev_item_to_cpu_v \ 102 )((d->x)); 103 104 # define DEFINE_CONV_ONE(t,n,m,...) \ 105 static inline struct t * n(struct t * d) { \ 106 CALL_MACRO_FOR_EACH(m, ##__VA_ARGS__) \ 107 return d; \ 108 } 109 110 /* Finally define the DEFINE_CONV macro */ 111 # define DEFINE_CONV(n,...) \ 112 DEFINE_CONV_ONE(n,n##_to_disk,DEFINE_CONV_CPU_TO_LE,##__VA_ARGS__) \ 113 DEFINE_CONV_ONE(n,n##_to_cpu,DEFINE_CONV_LE_TO_CPU,##__VA_ARGS__) 114 115 # define DEFINE_CONV_ALT(n,a,...) \ 116 DEFINE_CONV_ONE(n,n##_to_disk_##a,DEFINE_CONV_CPU_TO_LE, \ 117 ##__VA_ARGS__) \ 118 DEFINE_CONV_ONE(n,n##_to_cpu_##a,DEFINE_CONV_LE_TO_CPU,##__VA_ARGS__) 119 120 #endif /* !defined(__LITTLE_ENDIAN) */ 121 122 DEFINE_CONV(btrfs_key, objectid, offset) 123 DEFINE_CONV(btrfs_dev_item, devid, total_bytes, bytes_used, io_align, io_width, 124 sector_size, type, generation, start_offset, dev_group) 125 DEFINE_CONV(btrfs_stripe, devid, offset) 126 DEFINE_CONV(btrfs_chunk, length, owner, stripe_len, type, io_align, io_width, 127 sector_size, num_stripes, sub_stripes) 128 DEFINE_CONV(btrfs_free_space_entry, offset, bytes) 129 DEFINE_CONV(btrfs_free_space_header, location, generation, num_entries, 130 num_bitmaps) 131 DEFINE_CONV(btrfs_extent_item, refs, generation, flags) 132 DEFINE_CONV(btrfs_tree_block_info, key) 133 DEFINE_CONV(btrfs_extent_data_ref, root, objectid, offset, count) 134 DEFINE_CONV(btrfs_shared_data_ref, count) 135 DEFINE_CONV(btrfs_extent_inline_ref, offset) 136 DEFINE_CONV(btrfs_dev_extent, chunk_tree, chunk_objectid, chunk_offset, length) 137 DEFINE_CONV(btrfs_inode_ref, index, name_len) 138 DEFINE_CONV(btrfs_inode_extref, parent_objectid, index, name_len) 139 DEFINE_CONV(btrfs_timespec, sec, nsec) 140 DEFINE_CONV(btrfs_inode_item, generation, transid, size, nbytes, block_group, 141 nlink, uid, gid, mode, rdev, flags, sequence, atime, ctime, mtime, 142 otime) 143 DEFINE_CONV(btrfs_dir_log_item, end) 144 DEFINE_CONV(btrfs_dir_item, location, transid, data_len, name_len) 145 DEFINE_CONV(btrfs_root_item, inode, generation, root_dirid, bytenr, byte_limit, 146 bytes_used, last_snapshot, flags, refs, drop_progress, 147 generation_v2, ctransid, otransid, stransid, rtransid, ctime, 148 otime, stime, rtime) 149 DEFINE_CONV(btrfs_root_ref, dirid, sequence, name_len) 150 DEFINE_CONV(btrfs_file_extent_item, generation, ram_bytes, other_encoding, 151 disk_bytenr, disk_num_bytes, offset, num_bytes) 152 DEFINE_CONV_ALT(btrfs_file_extent_item, inl, generation, ram_bytes, 153 other_encoding) 154 DEFINE_CONV(btrfs_dev_replace_item, src_devid, cursor_left, cursor_right, 155 cont_reading_from_srcdev_mode, replace_state, time_started, 156 time_stopped, num_write_errors, num_uncorrectable_read_errors) 157 DEFINE_CONV(btrfs_block_group_item, used, chunk_objectid, flags) 158 DEFINE_CONV(btrfs_free_space_info, extent_count, flags) 159 160 DEFINE_CONV(btrfs_header, bytenr, flags, generation, owner, nritems) 161 DEFINE_CONV(btrfs_root_backup, tree_root, tree_root_gen, chunk_root, 162 chunk_root_gen, extent_root, extent_root_gen, fs_root, fs_root_gen, 163 dev_root, dev_root_gen, csum_root, csum_root_gen, total_bytes, 164 bytes_used, num_devices) 165 DEFINE_CONV(btrfs_super_block, bytenr, flags, magic, generation, root, 166 chunk_root, log_root, log_root_transid, total_bytes, bytes_used, 167 root_dir_objectid, num_devices, sectorsize, nodesize, 168 __unused_leafsize, stripesize, sys_chunk_array_size, 169 chunk_root_generation, compat_flags, compat_ro_flags, 170 incompat_flags, csum_type, dev_item, cache_generation, 171 uuid_tree_generation, super_roots[0], super_roots[1], 172 super_roots[2], super_roots[3]) 173 DEFINE_CONV(btrfs_item, key, offset, size) 174 DEFINE_CONV(btrfs_key_ptr, key, blockptr, generation) 175 176 #endif /* __BTRFS_CONV_FUNCS_H__ */ 177