[PATCH 0/3] ntfs: fix quota out-of-date marking

[DaeMyung Kang <charsyam@gmail.com>]

This series fixes NTFS quota out-of-date marking in fs/ntfs.

The driver already has quota compatibility code: it loads
FILE_Extend/$Quota, opens the $Q index, and has
ntfs_mark_quotas_out_of_date() to set QUOTA_FLAG_OUT_OF_DATE so Windows
can rescan quota usage.  The failures were not an intentional quota block;
the code could not reach and update the $Quota/$Q defaults entry correctly.

Patch 1 fixes ntfs_index_lookup() so callers looking up view indexes get
the index entry value instead of the key.  Directory $I30 callers keep the
existing key-return behavior.  The patch uses the index root type, not the
collation rule, to choose between $FILE_NAME keys and view-index values. It
also validates the returned value bounds without truncating the minimum
offset, excludes the child VCN tail from INDEX_ENTRY_NODE value ranges, and
clears the returned context pointers before returning an invalid view-index
entry error.  The matched-entry data exposure and validation are moved into
a small helper, ntfs_index_lookup_set_data(), so the done label stays flat
and the bounds check has a single return.

Patch 2 fixes ntfs_mark_quotas_out_of_date() to look up $Quota/$Q by the
$Q index name, not $I30.

Patch 3 calls ntfs_mark_quotas_out_of_date() during initial read-write mount
as well as the existing read-only to read-write remount path.  The init
sequence is wrapped in a small helper, ntfs_init_quota_for_mount(), which
captures each call result in a local variable, derives the failure reason,
and gates the read-only downgrade on policy in one place — keeping
ntfs_load_system_files() flat.

QEMU/virtme testing:

- The original remount-rw reproducer failed with:
  "Lookup of quota defaults entry failed."
- After changing only the quota index name, the same path exposed the second
  bug and failed with:
  "Quota defaults entry size is invalid.  Run chkdsk."
- With this series applied:
  - read-only mount followed by remount,rw succeeds
  - with the $Quota/$Q defaults flags prepared as 0x00000011, remount,rw
    persists 0x00000211
  - direct rw mount with the same prepared image also persists 0x00000211

DaeMyung Kang (3):
  ntfs: return view index entry data from lookup
  ntfs: use $Q when marking quotas out of date
  ntfs: mark quotas out of date on initial rw mount

 fs/ntfs/index.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 fs/ntfs/index.h |  3 +-
 fs/ntfs/quota.c |  3 +-
 fs/ntfs/super.c | 46 ++++++++++++++++++++++++++--------
 4 files changed, 110 insertions(+), 17 deletions(-)

-- 
2.43.0