generic/223, xfs/203: IO is not well aligned

On certain configurations (e.g. MOUNT_OPTIONS="-o dax") we get
different allocation patterns due to the writes being done in
multiple pwrite() calls. e.g. the write is 8k, but the buffer size
is 4k, and so the filesystem sees 4k writes. If the filesytem is not
using delayed allocation, then the allocation context is a 4k write
rather than an 8k write and so they don't get appropriately aligned.

Fix this by making the write buffer the same size and the writes
being done.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Dave Chinner
2015-05-26 12:51:53 +10:00
committed by Dave Chinner
parent 81d9c7039a
commit 6bd4b513af
2 changed files with 3 additions and 3 deletions
+1 -1
View File
@@ -69,7 +69,7 @@ for SUNIT_K in 8 16 32 64 128; do
$XFS_IO_PROG -f -c "falloc 0 $SIZE" \
$SCRATCH_MNT/file-$FILE-$SIZE-falloc \
>> $seqres.full 2>&1
$XFS_IO_PROG -f -c "pwrite 0 $SIZE" \
$XFS_IO_PROG -f -c "pwrite -b $SIZE 0 $SIZE" \
$SCRATCH_MNT/file-$FILE-$SIZE-write \
>> $seqres.full 2>&1
src/t_stripealign $SCRATCH_MNT/file-$FILE-$SIZE-falloc \
+2 -2
View File
@@ -38,11 +38,11 @@ _write_holes()
let fsize=$(($writes * 0x100000))
# prevent EOF preallocation from affecting results
xfs_io -f $file -c "truncate $fsize"
$XFS_IO_PROG -f $file -c "truncate $fsize"
offset=0
for i in `seq 0 $writes`; do
xfs_io -f $file -c "pwrite -q $offset 64k"
$XFS_IO_PROG -f $file -c "pwrite -b 64k -q $offset 64k"
let offset=$offset+0x100000
done
}