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[PULL 27/36] iotests: Disable 125 on broken XFS versions
From: |
Max Reitz |
Subject: |
[PULL 27/36] iotests: Disable 125 on broken XFS versions |
Date: |
Thu, 10 Oct 2019 13:42:51 +0200 |
And by that I mean all XFS versions, as far as I can tell. All details
are in the comment below.
We never noticed this problem because we only read the first number from
qemu-img info's "disk size" output -- and that is effectively useless,
because qemu-img prints a human-readable value (which generally includes
a decimal point). That will be fixed in the next patch.
Signed-off-by: Max Reitz <address@hidden>
Message-id: address@hidden
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Max Reitz <address@hidden>
---
tests/qemu-iotests/125 | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/tests/qemu-iotests/125 b/tests/qemu-iotests/125
index df328a63a6..0ef51f1e21 100755
--- a/tests/qemu-iotests/125
+++ b/tests/qemu-iotests/125
@@ -49,6 +49,46 @@ if [ -z "$TEST_IMG_FILE" ]; then
TEST_IMG_FILE=$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.
--
2.21.0
- [PULL 14/36] iotests: prepare 124 and 257 bitmap querying for backup-top filter, (continued)
- [PULL 14/36] iotests: prepare 124 and 257 bitmap querying for backup-top filter, Max Reitz, 2019/10/10
- [PULL 16/36] iotests: 257: drop device_add, Max Reitz, 2019/10/10
- [PULL 18/36] qapi: add unmap to BlockDeviceStats, Max Reitz, 2019/10/10
- [PULL 19/36] block: add empty account cookie type, Max Reitz, 2019/10/10
- [PULL 20/36] ide: account UNMAP (TRIM) operations, Max Reitz, 2019/10/10
- [PULL 21/36] scsi: store unmap offset and nb_sectors in request struct, Max Reitz, 2019/10/10
- [PULL 22/36] scsi: move unmap error checking to the complete callback, Max Reitz, 2019/10/10
- [PULL 23/36] scsi: account unmap operations, Max Reitz, 2019/10/10
- [PULL 24/36] file-posix: account discard operations, Max Reitz, 2019/10/10
- [PULL 25/36] qapi: query-blockstat: add driver specific file-posix stats, Max Reitz, 2019/10/10
- [PULL 27/36] iotests: Disable 125 on broken XFS versions,
Max Reitz <=
- [PULL 26/36] iotests: Fix 125 for growth_mode = metadata, Max Reitz, 2019/10/10
- [PULL 28/36] iotests: Use stat -c %b in 125, Max Reitz, 2019/10/10
- [PULL 29/36] block/backup: move in-flight requests handling from backup to block-copy, Max Reitz, 2019/10/10
- [PULL 30/36] block/backup: move write_flags calculation inside backup_job_create, Max Reitz, 2019/10/10
- [PULL 31/36] block/block-copy: split block_copy_set_callbacks function, Max Reitz, 2019/10/10
- [PULL 34/36] nbd: add empty .bdrv_reopen_prepare, Max Reitz, 2019/10/10
- [PULL 32/36] block: introduce backup-top filter driver, Max Reitz, 2019/10/10
- [PULL 36/36] iotests/162: Fix for newer Linux 5.3+, Max Reitz, 2019/10/10
- [PULL 35/36] tests: fix I/O test for hosts defaulting to LUKSv2, Max Reitz, 2019/10/10
- [PULL 33/36] block/backup: use backup-top instead of write notifiers, Max Reitz, 2019/10/10