ntfs: mount hibernated volumes read-only regardless of errors=

The hibernation check in load_system_files() only converts the
superblock to read-only under errors=remount-ro.  With the default
errors=continue (and with errors=panic), a hibernated volume is
mounted read-write and the mount-time $LogFile emptying writes to it,
although a hibernated volume must not be written to at all.

Drop the on_errors term so that a hibernated volume, or a volume whose
hibernation state cannot be determined, always mounts read-only.
NVolErrors() is still recorded, so ntfs_reconfigure() keeps refusing
remounts to read-write, and the $LogFile emptying is skipped by its
!sb_rdonly() check.

The check itself must not apply the errors= policy either: it runs
before SB_RDONLY is set, and ntfs_lookup_inode_by_name() and ntfs_iget()
call ntfs_error() internally on corruption or I/O errors, which under
errors=panic would panic the machine before the read-only fallback has
made its decision.  Temporarily substitute errors=remount-ro for
errors=panic around the check: nested ntfs_error() calls then fall
back to read-only, and any read-only transition they trigger is
preserved even when the error is not propagated to the check's return
value or recorded in NVolErrors().  This is safe during initial mount,
before the super block is published.

If the check reports hibernation or fails, set SB_RDONLY and record
NVolErrors() unconditionally: hibernation safety takes precedence over
the errors= policy.  A volume with errors recorded during the check or
earlier in the mount, e.g. when loading the LogFile, also stays
read-only, matching what ntfs_reconfigure() enforces for remounts.

Fixes: 6251f0b0de7d ("ntfs: update super block operations")
Cc: stable@vger.kernel.org
Suggested-by: Baolin Liu <liubaolin@kylinos.cn>
Reviewed-by: Baolin Liu <liubaolin@kylinos.cn>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

0 files changed, 0 insertions, 0 deletions