hfsplus: fix volume corruption issue for generic/498

hfsplus: fix volume corruption issue for generic/498

The xfstests' test-case generic/498 leaves HFS+ volume
in corrupted state:

sudo ./check generic/498
FSTYP -- hfsplus
PLATFORM -- Linux/x86_64 hfsplus-testing-0001 6.18.0-rc1+ #18 SMP PREEMPT_DYNAMIC Thu Dec 4 12:24:45 PST 2025
MKFS_OPTIONS -- /dev/loop51
MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch

generic/498 _check_generic_filesystem: filesystem on /dev/loop51 is inconsistent
(see XFSTESTS-2/xfstests-dev/results//generic/498.full for details)

Ran: generic/498
Failures: generic/498
Failed 1 of 1 tests

sudo fsck.hfsplus -d /dev/loop51
** /dev/loop51
Using cacheBlockSize=32K cacheTotalBlock=1024 cacheSize=32768K.
Executing fsck_hfs (version 540.1-Linux).
** Checking non-journaled HFS Plus Volume.
The volume name is untitled
** Checking extents overflow file.
** Checking catalog file.
Invalid leaf record count
(It should be 16 instead of 2)
** Checking multi-linked files.
CheckHardLinks: found 1 pre-Leopard file inodes.
** Checking catalog hierarchy.
** Checking extended attributes file.
** Checking volume bitmap.
** Checking volume information.
Verify Status: VIStat = 0x0000, ABTStat = 0x0000 EBTStat = 0x0000
CBTStat = 0x8000 CatStat = 0x00000000
** Repairing volume.
** Rechecking volume.
** Checking non-journaled HFS Plus Volume.
The volume name is untitled
** Checking extents overflow file.
** Checking catalog file.
** Checking multi-linked files.
CheckHardLinks: found 1 pre-Leopard file inodes.
** Checking catalog hierarchy.
** Checking extended attributes file.
** Checking volume bitmap.
** Checking volume information.
** The volume untitled was repaired successfully.

The generic/498 test executes such steps on final phase:

mkdir $SCRATCH_MNT/A
mkdir $SCRATCH_MNT/B
mkdir $SCRATCH_MNT/A/C
touch $SCRATCH_MNT/B/foo
$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/B/foo

ln $SCRATCH_MNT/B/foo $SCRATCH_MNT/A/C/foo
$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/A

"Simulate a power failure and mount the filesystem
to check that what we explicitly fsync'ed exists."

_flakey_drop_and_remount

The FSCK tool complains about "Invalid leaf record count".
HFS+ b-tree header contains leaf_count field is updated
by hfs_brec_insert() and hfs_brec_remove(). The hfs_brec_insert()
is involved into hard link creation process. However,
modified in-core leaf_count field is stored into HFS+
b-tree header by hfs_btree_write() method. But,
unfortunately, hfs_btree_write() hasn't been called
by hfsplus_cat_write_inode() and hfsplus_file_fsync()
stores not fully consistent state of the Catalog File's
b-tree.

This patch adds calling hfs_btree_write() method in
the hfsplus_cat_write_inode() with the goal of
storing consistent state of Catalog File's b-tree.
Finally, it makes FSCK tool happy.

sudo ./check generic/498
FSTYP         -- hfsplus
PLATFORM      -- Linux/x86_64 hfsplus-testing-0001 6.18.0-rc1+ #22 SMP PREEMPT_DYNAMIC Sat Dec  6 17:01:31 PST 2025
MKFS_OPTIONS  -- /dev/loop51
MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch

generic/498 33s ...  31s
Ran: generic/498
Passed all 1 tests

Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Yangtao Li <frank.li@vivo.com>
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20251207035821.3863657-1-slava@dubeyko.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>