Allow for more file system support by making a choice to use posix_fallocate instead of fallocate about chunkio

[edsiper]

thanks, this will be added (no ETA)

[sirwio]

While the pull request #64 addresses the issue on modern linux operating system it still fails on older linuxes e.g. Suse 11 SP4

suse:/chunkio # ./cio -e 5  -p 400kb.txt
[src/cio_file.c:332 errno=95] Operation not supported
[chunkio] cannot adjust chunk size '/tmp/cio-perf//test-perf/perf-test-0000.txt' to 4096 bytes
[src/cio_file.c:332 errno=95] Operation not supported
[chunkio] cannot adjust chunk size '/tmp/cio-perf//test-perf/perf-test-0001.txt' to 4096 bytes
[src/cio_file.c:332 errno=95] Operation not supported
[chunkio] cannot adjust chunk size '/tmp/cio-perf//test-perf/perf-test-0002.txt' to 4096 bytes
[src/cio_file.c:332 errno=95] Operation not supported
[chunkio] cannot adjust chunk size '/tmp/cio-perf//test-perf/perf-test-0003.txt' to 4096 bytes
[src/cio_file.c:332 errno=95] Operation not supported
[chunkio] cannot adjust chunk size '/tmp/cio-perf//test-perf/perf-test-0004.txt' to 4096 bytes
=== perf write ===
-  crc32 checksum : disabled
-  fs sync mode   : normal
-  file size      : 400.0K (409600 bytes)
-  total files    : 5
-  file writes    : 5
-  bytes written  : 0b (0 bytes)
-  elapsed time   : 0.00 seconds
-  rate           : 0b per second (0.00 bytes)
suse:/chunkio # cat /etc/SuSE-
SuSE-brand    SuSE-release
suse:/chunkio # cat /etc/SuSE-
SuSE-brand    SuSE-release
suse:/chunkio # cat /etc/SuSE-release
SUSE Linux Enterprise Server 11 (x86_64)
VERSION = 11
PATCHLEVEL = 4

This is due to the call to fallocate does not return EOPNOTSUPP but rather -1 with the errno 95 (Operation not supported).

To support older operating system it would be better to check for non zero return codes and revert to posix_fallocate in such case.

from chunkio.