fs/fiemap.h

/*
Copyright 2022 The Photon Authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

#pragma once
#include <cinttypes>

namespace photon {
namespace fs
{
    typedef uint32_t __u32;
    typedef uint64_t __u64;

    struct fiemap_extent {
        __u64 fe_logical;  /* logical offset in bytes for the start of
                            * the extent from the beginning of the file */
        __u64 fe_physical; /* physical offset in bytes for the start
                            * of the extent from the beginning of the disk */
        __u64 fe_length;   /* length in bytes for this extent */
        __u64 fe_logical_end() { return fe_logical + fe_length; }
        __u64 fe_reserved64[2];
        __u32 fe_flags;    /* FIEMAP_EXTENT_* flags for this extent */
        __u32 fe_reserved[3];
    };

    struct fiemap {
        __u64 fm_start;         /* logical offset (inclusive) at
                                 * which to start mapping (in) */
        __u64 fm_length;        /* logical length of mapping which
                                 * userspace wants (in) */
        __u32 fm_flags = 0;     /* FIEMAP_FLAG_* flags for request (in/out) */
        __u32 fm_mapped_extents;/* number of extents that were mapped (out) */
        __u32 fm_extent_count;  /* size of fm_extents array (in) */
        __u32 fm_reserved = 0;
        struct fiemap_extent fm_extents[0]; /* array of mapped extents (out) */

        fiemap(__u64 fm_start, __u64 fm_length, __u32 fm_extent_count) :
            fm_start(fm_start), fm_length(fm_length), fm_extent_count(fm_extent_count) { }
    };

    template<__u64 N>
    struct fiemap_t : public fiemap
    {
        struct fiemap_extent fm_extents[N];
        fiemap_t(__u64 fm_start, __u64 fm_length) : fiemap(fm_start, fm_length, N) { }
    };

#define FIEMAP_MAX_OFFSET   (~0ULL)

#define FIEMAP_FLAG_SYNC    0x00000001 /* sync file data before map */
#define FIEMAP_FLAG_XATTR   0x00000002 /* map extended attribute tree */
#define FIEMAP_FLAG_CACHE   0x00000004 /* request caching of the extents */

#define FIEMAP_FLAGS_COMPAT (FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR)

#define FIEMAP_EXTENT_LAST              0x00000001 /* Last extent in file. */
#define FIEMAP_EXTENT_UNKNOWN           0x00000002 /* Data location unknown. */
#define FIEMAP_EXTENT_DELALLOC          0x00000004 /* Location still pending.
                                                    * Sets EXTENT_UNKNOWN. */
#define FIEMAP_EXTENT_ENCODED           0x00000008 /* Data can not be read
                                                    * while fs is unmounted */
#define FIEMAP_EXTENT_DATA_ENCRYPTED    0x00000080 /* Data is encrypted by fs.
                                                    * Sets EXTENT_NO_BYPASS. */
#define FIEMAP_EXTENT_NOT_ALIGNED       0x00000100 /* Extent offsets may not be
                                                    * block aligned. */
#define FIEMAP_EXTENT_DATA_INLINE       0x00000200 /* Data mixed with metadata.
                                                    * Sets EXTENT_NOT_ALIGNED.*/
#define FIEMAP_EXTENT_DATA_TAIL         0x00000400 /* Multiple files in block.
                                                    * Sets EXTENT_NOT_ALIGNED.*/
#define FIEMAP_EXTENT_UNWRITTEN         0x00000800 /* Space allocated, but
                                                    * no data (i.e. zero). */
#define FIEMAP_EXTENT_MERGED            0x00001000 /* File does not natively
                                                    * support extents. Result
                                                    * merged for efficiency. */
#define FIEMAP_EXTENT_SHARED            0x00002000 /* Space shared with other
                                                    * files. */

}
}