btrfs-progs: fsck-tests: make the warning check more specific for 057

[BUG]
On older kernels without the fix ae4477f93756 ("btrfs: update
superblock's device bytes_used when dropping chunk"), the test case 057
will result super block device item to mismatch with the chunk one.

Normally this is not a big deal, but newer btrfs-progs will check for
such mismatch.
Although newer btrfs-progs won't report this as an error, the test case
fsck/057 will manually check for any warnings, and fail the test case:

  ====== RUN CHECK /home/runner/work/btrfs-progs/btrfs-progs/btrfs check /dev/loop1
  [1/8] checking log skipped (none written)
  [2/8] checking root items
  [3/8] checking extents
  WARNING: device 2's bytes_used was 503316480 in tree but 570425344 in superblock
  [4/8] checking free space tree
  [5/8] checking fs roots
  [6/8] checking only csums items (without verifying data)
  [7/8] checking root refs
  [8/8] checking quota groups skipped (not enabled on this FS)
  Opening filesystem to check...
  Checking filesystem on /dev/loop1
  UUID: efd3e3b9-2fac-4a6f-b378-34694dc2d446
  found 147456 bytes used, no error found
  total csum bytes: 0
  total tree bytes: 147456
  total fs tree bytes: 32768
  total extent tree bytes: 16384
  btree space waste bytes: 139992
  file data blocks allocated: 0
   referenced 0

That WARNING line will fail the test case, even if we didn't error out.

[CAUSE]
The test case itself is a test case for btrfs-progs commit 0dc8b8b
("btrfs-progs: check: fix wrong total bytes check for seed device"),
which will report minor warning like the following:

  [2/7] checking extents
  WARNING: minor unaligned/mismatch device size detected
  WARNING: recommended to use 'btrfs rescue fix-device-size' to fix it

But in this particular case, 057 should only check for the related
wanrings, not something caused by the kernel.

[FIX]
Make the warning check in fsck/057 more specific, instead of "WARNING"
use "fix-device-size" as the keyword.

This is an unfortunate workaround for the CI kernels, which doesn't have
fast enough backport of upstream kernel fixes.

Reviewed-by: Boris Burkov <[email protected]>
Signed-off-by: Qu Wenruo <[email protected]>

Author: adam900710

tests/fsck-tests/057-seed-false-alerts/test.sh

@@ -35,13 +35,13 @@ sprouted_output=$(_mktemp btrfs-progs-sprouted-check-stdout.XXXXXX)
 run_check_stdout $SUDO_HELPER "$TOP/btrfs" check "$dev1" >> "$seed_output"
 run_check_stdout $SUDO_HELPER "$TOP/btrfs" check "$dev2" >> "$sprouted_output"
 
-# There should be no warning for both seed and sprouted fs
-if grep -q "WARNING" "$seed_output"; then
+# There should be no warning about the device size for both seed and sprouted fs
+if grep -q "fix-device-size" "$seed_output"; then
 	cleanup_loopdevs
 	rm -f -- "$seed_output" "$sprouted_output"
 	_fail "false alerts detected for seed fs"
 fi
-if grep -q "WARNING" "$sprouted_output"; then
+if grep -q "fix-device-size" "$sprouted_output"; then
 	cleanup_loopdevs
 	rm -f -- "$seed_output" "$sprouted_output"
 	_fail "false alerts detected for sprouted fs"