iotests: Disable 125 on broken XFS versions

    TEST_IMG_FILE=$TEST_IMG

fi

# Test whether we are running on a broken XFS version.  There is this

# bug:

# $ rm -f foo

# $ touch foo

# $ block_size=4096 # Your FS's block size

# $ fallocate -o $((block_size / 2)) -l $block_size foo

# $ LANG=C xfs_bmap foo | grep hole

#         1: [8..15]: hole

#

# The problem is that the XFS driver rounds down the offset and

# rounds up the length to the block size, but independently.  As

# such, it only allocates the first block in the example above,

# even though it should allocate the first two blocks (because our

# request is to fallocate something that touches both the first

# two blocks).

#

# This means that when you then write to the beginning of the

# second block, the disk usage of the first two blocks grows.

#

# That is precisely what fallocate() promises, though: That when you

# write to an area that you have fallocated, no new blocks will have

# to be allocated.

touch "$TEST_IMG_FILE"

# Assuming there is no FS with a block size greater than 64k

fallocate -o 65535 -l 2 "$TEST_IMG_FILE"

len0=$(get_image_size_on_host)

# Write to something that in theory we have just fallocated

# (Thus, the on-disk size should not increase)

poke_file "$TEST_IMG_FILE" 65536 42

len1=$(get_image_size_on_host)

if [ $len1 -gt $len0 ]; then

    _notrun "the test filesystem's fallocate() is broken"

fi

rm -f "$TEST_IMG_FILE"

# Generally, we create some image with or without existing preallocation and

# then resize it. Then we write some data into the image and verify that its

# size does not change if we have used preallocation.