On 20/08/25 1:45 pm, Nirjhar Roy (IBM) wrote:
This test was written with 4k block size in mind and it fails with
64k block size when tested with btrfs.
The test first does pre-allocation, then fills up the
filesystem. After that it tries to fragment and fill holes at offsets
of 4k(i.e, 1 fsblock) - which works fine with 4k block size, but with
64k block size, the test tries to fragment and fill holes within
1 fsblock(of size 64k). This results in overwrite of 64k fsblocks
and the write fails. The reason for this failure is that during
overwrite, there is no more space available for COW.
Fix this by changing the pwrite block size and offsets to 64k
so that the test never tries to punch holes or overwrite within 1 fsblock
and the test becomes compatible with all block sizes.
For non-COW filesystems/files, this test should work even if the
underlying filesytem block size > 64k.
Reported-by: Disha Goel <disgoel@xxxxxxxxxxxxx>
Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@xxxxxxxxx>
I tested it on Power, and the generic/274 test passes with both 4k & 64k
block sizes.
SECTION -- btrfs_64k
RECREATING -- btrfs on /dev/loop0
FSTYP -- btrfs
PLATFORM -- Linux/ppc64le localhost 6.17.0-rc2-00060-g068a56e56fa8
#3 SMP Thu Aug 21 17:54:04 IST 2025
MKFS_OPTIONS -- -f -s 65536 -n 65536 /dev/loop1
MOUNT_OPTIONS -- /dev/loop1 /mnt/scratch
generic/274 53s ... 57s
Ran: generic/274
Passed all 1 tests
Tested-by: Disha Goel <disgoel@xxxxxxxxxxxxx>
---
tests/generic/274 | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/tests/generic/274 b/tests/generic/274
index 916c7173..f6c7884e 100755
--- a/tests/generic/274
+++ b/tests/generic/274
@@ -40,8 +40,8 @@ _scratch_unmount 2>/dev/null
_scratch_mkfs_sized $((2 * 1024 * 1024 * 1024)) >>$seqres.full 2>&1
_scratch_mount
-# Create a 4k file and Allocate 4M past EOF on that file
-$XFS_IO_PROG -f -c "pwrite 0 4k" -c "falloc -k 4k 4m" $SCRATCH_MNT/test \
+# Create a 64k file and Allocate 64M past EOF on that file
+$XFS_IO_PROG -f -c "pwrite 0 64k" -c "falloc -k 64k 64m" $SCRATCH_MNT/test \
>>$seqres.full 2>&1 || _fail "failed to create test file"
# Fill the rest of the fs completely
@@ -63,7 +63,7 @@ df $SCRATCH_MNT >>$seqres.full 2>&1
echo "Fill in prealloc space; fragment at offsets:" >> $seqres.full
for i in `seq 1 2 1023`; do
echo -n "$i " >> $seqres.full
- dd if=/dev/zero of=$SCRATCH_MNT/test seek=$i bs=4K count=1 conv=notrunc \
+ dd if=/dev/zero of=$SCRATCH_MNT/test seek=$i bs=64K count=1 conv=notrunc \
>>$seqres.full 2>/dev/null || _fail "failed to write to test file"
done
_scratch_sync
@@ -71,7 +71,7 @@ echo >> $seqres.full
echo "Fill in prealloc space; fill holes at offsets:" >> $seqres.full
for i in `seq 2 2 1023`; do
echo -n "$i " >> $seqres.full
- dd if=/dev/zero of=$SCRATCH_MNT/test seek=$i bs=4K count=1 conv=notrunc \
+ dd if=/dev/zero of=$SCRATCH_MNT/test seek=$i bs=64K count=1 conv=notrunc \
>>$seqres.full 2>/dev/null || _fail "failed to fill test file"
done
_scratch_sync
