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Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/conv-funcs.h | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/fs/btrfs/conv-funcs.h b/fs/btrfs/conv-funcs.h new file mode 100644 index 0000000000..f2e7944e4e --- /dev/null +++ b/fs/btrfs/conv-funcs.h @@ -0,0 +1,176 @@ +/* + * Functions to convert BTRFS structures from disk to CPU endianness and back. + * + * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef __BTRFS_CONV_FUNCS_H__ +#define __BTRFS_CONV_FUNCS_H__ + +#include "ctree.h" +#include <u-boot/variadic-macro.h> +#include <asm/byteorder.h> + +/* We are using variadic macros and C11 _Generic to achieve compact code. + + We want to define macro DEFINE_CONV(x, ...), where the first argument is the + name of the structure for which it shall define conversion functions (the + names of the functions shall be x_to_cpu and x_to_disk), and the other + arguments are names of the members on which the functions shall do + endianness conversion. */ + +#if defined(__LITTLE_ENDIAN) + +/* If the target machine is little endian, the conversion functions do + nothing, since the on disk format is little endian. */ + +# define DEFINE_CONV(n,...) \ + static inline struct n *n##_to_disk(struct n * r) \ + { \ + return r; \ + } \ + static inline struct n *n##_to_cpu(struct n * r) \ + { \ + return r; \ + } + +# define DEFINE_CONV_ALT(n,a,...) \ + static inline struct n *n##_to_disk_##a(struct n * r) \ + { \ + return r; \ + } \ + static inline struct n *n##_to_cpu_##a(struct n * r) \ + { \ + return r; \ + } + +#else /* !defined(__LITTLE_ENDIAN) */ + +/* Some structures contain not only scalar members, but compound types as well + (for example, struct btrfs_inode_item contains members of type struct + btrfs_timespec. + + For these members we want to call the conversion function recursively, so + first we declare the functions taking pointers to this types (these function + will be defined later by the DEFINE_CONV macro) and then we define + correspond functions taking non-pointers, so that they can be used in the + expansion of the _Generic. */ +# define DEFINE_CONV_FOR_STRUCT(n) \ + static inline struct n * n##_to_disk(struct n *); \ + static inline struct n * n##_to_cpu(struct n *); \ + static inline struct n n##_to_disk_v(struct n x) { \ + return *n##_to_disk(&x); \ + } \ + static inline struct n n##_to_cpu_v(struct n x) { \ + return *n##_to_cpu(&x); \ + } + +DEFINE_CONV_FOR_STRUCT(btrfs_key) +DEFINE_CONV_FOR_STRUCT(btrfs_stripe) +DEFINE_CONV_FOR_STRUCT(btrfs_timespec) +DEFINE_CONV_FOR_STRUCT(btrfs_inode_item) +DEFINE_CONV_FOR_STRUCT(btrfs_root_backup) +DEFINE_CONV_FOR_STRUCT(btrfs_dev_item) + +/* Now define the _Generic for both CPU to LE and LE to CPU */ +# define DEFINE_CONV_CPU_TO_LE(x) \ + (d->x) = _Generic((d->x), \ + __u16: cpu_to_le16, \ + __u32: cpu_to_le32, \ + __u64: cpu_to_le64, \ + struct btrfs_key: btrfs_key_to_disk_v, \ + struct btrfs_stripe: btrfs_stripe_to_disk_v, \ + struct btrfs_timespec: btrfs_timespec_to_disk_v, \ + struct btrfs_inode_item: btrfs_inode_item_to_disk_v, \ + struct btrfs_root_backup: btrfs_root_backup_to_disk_v, \ + struct btrfs_dev_item: btrfs_dev_item_to_disk_v \ + )((d->x)); + +# define DEFINE_CONV_LE_TO_CPU(x) \ + (d->x) = _Generic((d->x), \ + __u16: le16_to_cpu, \ + __u32: le32_to_cpu, \ + __u64: le64_to_cpu, \ + struct btrfs_key: btrfs_key_to_cpu_v, \ + struct btrfs_stripe: btrfs_stripe_to_cpu_v, \ + struct btrfs_timespec: btrfs_timespec_to_cpu_v, \ + struct btrfs_inode_item: btrfs_inode_item_to_cpu_v, \ + struct btrfs_root_backup: btrfs_root_backup_to_cpu_v, \ + struct btrfs_dev_item: btrfs_dev_item_to_cpu_v \ + )((d->x)); + +# define DEFINE_CONV_ONE(t,n,m,...) \ + static inline struct t * n(struct t * d) { \ + CALL_MACRO_FOR_EACH(m, ##__VA_ARGS__) \ + return d; \ + } + +/* Finally define the DEFINE_CONV macro */ +# define DEFINE_CONV(n,...) \ + DEFINE_CONV_ONE(n,n##_to_disk,DEFINE_CONV_CPU_TO_LE,##__VA_ARGS__) \ + DEFINE_CONV_ONE(n,n##_to_cpu,DEFINE_CONV_LE_TO_CPU,##__VA_ARGS__) + +# define DEFINE_CONV_ALT(n,a,...) \ + DEFINE_CONV_ONE(n,n##_to_disk_##a,DEFINE_CONV_CPU_TO_LE, \ + ##__VA_ARGS__) \ + DEFINE_CONV_ONE(n,n##_to_cpu_##a,DEFINE_CONV_LE_TO_CPU,##__VA_ARGS__) + +#endif /* !defined(__LITTLE_ENDIAN) */ + +DEFINE_CONV(btrfs_key, objectid, offset) +DEFINE_CONV(btrfs_dev_item, devid, total_bytes, bytes_used, io_align, io_width, + sector_size, type, generation, start_offset, dev_group) +DEFINE_CONV(btrfs_stripe, devid, offset) +DEFINE_CONV(btrfs_chunk, length, owner, stripe_len, type, io_align, io_width, + sector_size, num_stripes, sub_stripes) +DEFINE_CONV(btrfs_free_space_entry, offset, bytes) +DEFINE_CONV(btrfs_free_space_header, location, generation, num_entries, + num_bitmaps) +DEFINE_CONV(btrfs_extent_item, refs, generation, flags) +DEFINE_CONV(btrfs_tree_block_info, key) +DEFINE_CONV(btrfs_extent_data_ref, root, objectid, offset, count) +DEFINE_CONV(btrfs_shared_data_ref, count) +DEFINE_CONV(btrfs_extent_inline_ref, offset) +DEFINE_CONV(btrfs_dev_extent, chunk_tree, chunk_objectid, chunk_offset, length) +DEFINE_CONV(btrfs_inode_ref, index, name_len) +DEFINE_CONV(btrfs_inode_extref, parent_objectid, index, name_len) +DEFINE_CONV(btrfs_timespec, sec, nsec) +DEFINE_CONV(btrfs_inode_item, generation, transid, size, nbytes, block_group, + nlink, uid, gid, mode, rdev, flags, sequence, atime, ctime, mtime, + otime) +DEFINE_CONV(btrfs_dir_log_item, end) +DEFINE_CONV(btrfs_dir_item, location, transid, data_len, name_len) +DEFINE_CONV(btrfs_root_item, inode, generation, root_dirid, bytenr, byte_limit, + bytes_used, last_snapshot, flags, refs, drop_progress, + generation_v2, ctransid, otransid, stransid, rtransid, ctime, + otime, stime, rtime) +DEFINE_CONV(btrfs_root_ref, dirid, sequence, name_len) +DEFINE_CONV(btrfs_file_extent_item, generation, ram_bytes, other_encoding, + disk_bytenr, disk_num_bytes, offset, num_bytes) +DEFINE_CONV_ALT(btrfs_file_extent_item, inl, generation, ram_bytes, + other_encoding) +DEFINE_CONV(btrfs_dev_replace_item, src_devid, cursor_left, cursor_right, + cont_reading_from_srcdev_mode, replace_state, time_started, + time_stopped, num_write_errors, num_uncorrectable_read_errors) +DEFINE_CONV(btrfs_block_group_item, used, chunk_objectid, flags) +DEFINE_CONV(btrfs_free_space_info, extent_count, flags) + +DEFINE_CONV(btrfs_header, bytenr, flags, generation, owner, nritems) +DEFINE_CONV(btrfs_root_backup, tree_root, tree_root_gen, chunk_root, + chunk_root_gen, extent_root, extent_root_gen, fs_root, fs_root_gen, + dev_root, dev_root_gen, csum_root, csum_root_gen, total_bytes, + bytes_used, num_devices) +DEFINE_CONV(btrfs_super_block, bytenr, flags, magic, generation, root, + chunk_root, log_root, log_root_transid, total_bytes, bytes_used, + root_dir_objectid, num_devices, sectorsize, nodesize, + __unused_leafsize, stripesize, sys_chunk_array_size, + chunk_root_generation, compat_flags, compat_ro_flags, + incompat_flags, csum_type, dev_item, cache_generation, + uuid_tree_generation, super_roots[0], super_roots[1], + super_roots[2], super_roots[3]) +DEFINE_CONV(btrfs_item, key, offset, size) +DEFINE_CONV(btrfs_key_ptr, key, blockptr, generation) + +#endif /* __BTRFS_CONV_FUNCS_H__ */ |