From ed0c3c33c6f7c28e5f05e96e1891251bdd181651 Mon Sep 17 00:00:00 2001 From: Bernhard Voelker Date: Tue, 16 Sep 2014 18:50:29 +0200 Subject: tests: fix false du failure on newer XFS On XFS, when creating the ~2G test file 'big' in a for-loop by appending 20M each time, the file ends up using ~4G - visible in 'st_blocks'. The unused space would be reclaimed later. This feature is called "speculative preallocation" which aims at avoiding fragmentation. According to the XFS FAQ [1], there are two particular aspects of XFS speculative preallocation that are triggering this: 1. "Applications that repeatedly trigger preallocation and reclaim cycles [after file close] can cause fragmentation. Therefore, this pattern is detected and causes the preallocation to persist beyond the lifecycle of the file descriptor." 2. "Preallocation sizes grow as files grow larger." [1] http://xfs.org/index.php/XFS_FAQ Avoid one of the above by only doing a single close (reclaim cycle). * tests/du/2g.sh: Similar to the fix for a dd test (see commit v8.22-65-g7c03fe2), avoid speculative preallocation by creating the 'big' file in one go instead of appending to it in the loop. Remove debugging statements as the output with 'set -x' is sufficient nowadays. --- tests/du/2g.sh | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'tests') diff --git a/tests/du/2g.sh b/tests/du/2g.sh index f766d4d9d..d7cc987d0 100755 --- a/tests/du/2g.sh +++ b/tests/du/2g.sh @@ -43,15 +43,14 @@ test $min_kb -lt $free_kb || big=big rm -f $big -test -t 1 || printf 'creating a 2GB file...\n' -for i in $(seq 100); do - # Note: 2147483648 == 2^31. Print floor(2^31/100) per iteration. - printf %21474836s x >> $big || fail=1 - # On the final iteration, append the remaining 48 bytes. - test $i = 100 && { printf %48s x >> $big || fail=1; } - test -t 1 && printf 'creating a 2GB file: %d%% complete\r' $i -done -echo +{ + for i in $(seq 100); do + # Note: 2147483648 == 2^31. Print floor(2^31/100) per iteration. + printf %21474836s x || fail=1 + done + # After the final iteration, append the remaining 48 bytes. + printf %48s x || fail=1 +} > $big || fail=1 du -k $big > out1 || fail=1 rm -f $big -- cgit v1.2.3-54-g00ecf