GitLab

As discovered by tracing, but also presenting in AIX fseeko
documentation, seeking beyond the EOF is acceptable, as you can write
there.

To display the same error in AIX to other implementations that return
errors on seek, we take the EFBIG error code on reading and error the
same way.

An AIX truss of an aspect of the test:

truss extra/innochecksum --page=18446744073709551615 $MYSQLD_DATADIR/test/tab1.ibd

  statx("./mysql-test/var/log/innodb_zip.innochecksum_3-4k,crc32,innodb/mysqld.1/data//test/tab1.ibd", 0x0FFFFFFFFFFFF610, 176, 010) = 0
  kopen("./mysql-test/var/log/innodb_zip.innochecksum_3-4k,crc32,innodb/mysqld.1/data//test/tab1.ibd", O_RDONLY|O_LARGEFILE) = 3
  kfcntl(3, 12, 0x00000001100006C8)               = 0
  kfcntl(3, F_GETFL, 0x00000001100A6CF8)          = 67108864
  kioctl(3, 22528, 0x0000000000000000, 0x0000000000000000) Err#25 ENOTTY
  klseek(3, 0, 1, 0x0FFFFFFFFFFFF3F0)             = 0
  kioctl(3, 22528, 0x0000000000000000, 0x0000000000000000) Err#25 ENOTTY
  kread(3, "DEADBEEF\0\0\0\0FFFFFFFF".., 4096)    = 4096
  klseek(3, 0, 1, 0x0FFFFFFFFFFFF450)             = 0
  klseek(3, 17592186040320, 0, 0x0FFFFFFFFFFFF450) = 0
  klseek(3, 0, 1, 0x0FFFFFFFFFFFF3F0)             = 0
  kread(3, "DEADBEEF\0\0\0\0FFFFFFFF".., 4096)    Err#27 EFBIG

An equivalent Linux trace:

ltrace extra/innochecksum --page=18446744073709551615 $MYSQLD_DATADIR/test/tab1.ibd

  stat64(0x7fff10ea2dc3, 0x7fff10ea0670, 88, 0x8026be41)         = 0
  open64("./mysql-test/var/log/innodb_zip."..., 0, 02072403160)  = 3
  fcntl64(3, 6, 0x139f180, 1)                                    = 0
  fgetpos64(0x615000000080, 0x7fff10ea0760, 1, 0)                = 0
  fseeko64(0x615000000080, 0xffffffff000, 0, 5 <unfinished ...>
  pthread_getspecific(0, 0x4d0eb8, 0x7fff10ea0490, 0)            = 0x7f7b2806d000
  <... fseeko64 resumed> )                                       = 0
  fgetpos64(0x615000000080, 0x7fff10ea0760, 1, 1)                = 0
  feof(0x615000000080)                                           = 0
  feof(0x615000000080)                                           = 1
  Error: Unable to seek to necessary offset