mirror_zfs/tests/zfs-tests/include/math.shlib
LOLi 99834d1950 Fix truncate(2) mtime and ctime handling
On Linux, ftruncate(2) always changes the file timestamps, even if the
file size is not changed. However, in case of a successfull
truncate(2), the timestamps are updated only if the file size changes.
This translates to the VFS calling the ZFS Posix Layer "setattr"
function (zpl_setattr) with ATTR_MTIME and ATTR_CTIME unconditionally
set on the iattr mask only when doing a ftruncate(2), while the
truncate(2) is left to the filesystem implementation to be dealt with.

This behaviour is consistent with POSIX:2004/SUSv3 specifications
where there's no explicit requirement for file size changes to update
the timestamps only for ftruncate(2):

http://pubs.opengroup.org/onlinepubs/009695399/functions/truncate.html
http://pubs.opengroup.org/onlinepubs/009695399/functions/ftruncate.html

This has been later updated in POSIX:2008/SUSv4 where, for both
truncate(2)/ftruncate(2), there's no mention of this size change
requirement:

http://austingroupbugs.net/view.php?id=489
http://pubs.opengroup.org/onlinepubs/9699919799/functions/truncate.html
http://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html

Unfortunately the Linux VFS is still calling into the ZPL without
ATTR_MTIME/ATTR_CTIME set in the truncate(2) case: we fix this by
explicitly updating the timestamps when detecting the ATTR_SIZE bit,
which is always set in do_truncate(), on the iattr mask.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6811 
Closes #6819
2017-11-13 09:24:26 -08:00

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#
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#
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# source. A copy of the CDDL is also available via the Internet at
# http://www.illumos.org/license/CDDL.
#
#
# Copyright (c) 2012, 2016 by Delphix. All rights reserved.
#
#
# Return 0 if the percentage difference between $a and $b is $percent or
# greater. Return 1 if the percentage is lower or if we would divide by
# zero. For use like this:
#
# Do $action if the calculated percentage is greater or equal to that passed in:
# within_percent A B P && $action
# Do $action if the calculated percentage is less than that passed in:
# within_percent A B P || $action
#
function within_percent
{
typeset a=$1
typeset b=$1
typeset percent=$3
# Set $a or $b to $2 such that a >= b
[[ '1' = $(echo "if ($2 > $a) 1" | bc) ]] && a=$2 || b=$2
# Prevent division by 0
[[ $a =~ [1-9] ]] || return 1
typeset p=$(echo "scale=2; $b * 100 / $a" | bc)
log_note "Comparing $a and $b given $percent% (calculated: $p%)"
[[ '1' = $(echo "scale=2; if ($p >= $percent) 1" | bc) ]] && return 0
return 1
}
#
# Return 0 if the human readable string of the form <value>[suffix] can
# be converted to bytes. Allow suffixes are shown in the table below.
#
function to_bytes
{
typeset size=$1
typeset value=$(echo "$size" | grep -o '[0-9]\+')
case $size in
*PB|*pb|*P|*p) factor='1024^5' ;;
*TB|*tb|*T|*t) factor='1024^4' ;;
*GB|*gb|*G|*g) factor='1024^3' ;;
*MB|*mb|*M|*m) factor='1024^2' ;;
*KB|*kb|*K|*k) factor='1024^1' ;;
*B|*b) factor='1024^0' ;;
*[!0-9.]*) return 1 ;;
*) factor='1024^0' ;;
esac
echo "$value * ($factor)" | bc
return 0
}
#
# Verify $a is equal to $b, otherwise raise an error specifying
# the $type of values being compared
#
function verify_eq # <a> <b> <type>
{
typeset a=$1
typeset b=$2
typeset type=$3
if [[ $a -ne $b ]]; then
log_fail "Compared $type should be equal: $a != $b"
fi
}
#
# Verify $a is not equal to $b, otherwise raise an error specifying
# the $type of values being compared
#
function verify_ne # <a> <b> <type>
{
typeset a=$1
typeset b=$2
typeset type=$3
if [[ $a -eq $b ]]; then
log_fail "Compared $type should be not equal: $a == $b"
fi
}