[PATCH v2 0/5] ntfs: fix incorrect error codes returned to callers

[Baolin Liu]

From: Baolin Liu <liubaolin@xxxxxxxxxx>

Changes in v2:
- Patch 2: Fixed ntfs_extent_inode_open() to use ERR_PTR() instead of NULL,
  so it can properly propagate error codes (suggested by maintainer).
  Updated ntfs_inode_attach_all_extents() to use IS_ERR()/PTR_ERR() to
  preserve the actual error code from ntfs_extent_inode_open().
- Patches 1, 3, 4, 5: No code changes, added Reviewed-by tag from Hyunchul Lee

Five places in fs/ntfs/ return the wrong error code: a real errno is
replaced by -1 or by a hardcoded substitute, so callers and userspace see
something unrelated to what actually went wrong. The fixes are
independent of each other.

Patch 1 is different from the rest: there the error is not just
mislabelled, it is not seen as an error at all. -1 is what a normal
comparison returns for "collates before", so ntfs_ie_lookup() acts on it
as a tree-descent hint, and a malformed entry in $Reparse/$R or $ObjId/$O
is silently treated as a lookup miss instead of being reported.

Patch 2 fixes ntfs_extent_inode_open() which had two bugs: it treated
map_mft_record() failure as success, and returned NULL for all errors
(losing error information). Now it returns ERR_PTR() with the actual
error code (-EIO, -ENOMEM, -EINVAL).

Patch 3 fixes a -1 return in inode.c that reaches userspace as EPERM.
It loses ENOSPC among others, so a full volume misreports create(),
mkdir() and link().

Patches 4 and 5 restore errors that are already available as an ERR_PTR.
Both collapse -ENOMEM into something else, so an allocation failure is
misreported.

No control flow is changed; every callee already returned these codes.

Based on ntfs-next (0fecc393f206).

Baolin Liu (5):
  ntfs: return -EINVAL from ntfs_collate_ntofs_ulongs() on bad length
  ntfs: fix error handling in ntfs_extent_inode_open and propagate errors
  ntfs: preserve the truncate error in ntfs_enlarge_attribute()
  ntfs: propagate the map_mft_record() error in ntfs_attrlist_entry_add()
  ntfs: propagate the ntfs_attr_iget() error in update_reparse_data()

 fs/ntfs/attrlist.c |  4 ++--
 fs/ntfs/collate.c  |  2 +-
 fs/ntfs/inode.c    | 28 ++++++++++++++++++----------
 fs/ntfs/reparse.c  |  2 +-
 4 files changed, 22 insertions(+), 14 deletions(-)

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2.51.0