[v3,0/3] iomap/xfs: fix stale data exposure when truncating realtime inodes

Message

Zhang Yi May 17, 2024, 11:13 a.m. UTC

From: Zhang Yi <[e-mail]>

Changes since v2:
 - Use div_u64_rem() instead of do_div().

Changes since v1:
 - In iomap_truncate_page() and dax_truncate_page(), for the case of
   truncate blocksize is not power of 2, use do_dive() to calculate the
   offset.

This series fix a stale data exposure issue reported by Chandan when
running fstests generic/561 on xfs with realtime device[1]. The real
problem is xfs_setattr_size() doesn't zero out enough range when
truncating a realtime inode, please see the third patch or [1] for
details.

The first two patches modify iomap_truncate_page() and
dax_truncate_page() to pass filesystem identified blocksize, and drop
the assumption of i_blocksize() as Dave suggested. The third patch fix
the issue by modifying xfs_truncate_page() to pass the correct
blocksize, and make sure zeroed range have been flushed to disk before
updating i_size.

[1] https://lore.kernel.org/linux-xfs/87ttj8ircu.fsf@debian-BULLSEYE-live-builder-AMD64/

Thanks,
Yi.

Zhang Yi (3):
  iomap: pass blocksize to iomap_truncate_page()
  fsdax: pass blocksize to dax_truncate_page()
  xfs: correct the zeroing truncate range

 fs/dax.c               | 13 +++++++++----
 fs/ext2/inode.c        |  4 ++--
 fs/iomap/buffered-io.c | 13 +++++++++----
 fs/xfs/xfs_iomap.c     | 36 ++++++++++++++++++++++++++++++++----
 fs/xfs/xfs_iops.c      | 10 ----------
 include/linux/dax.h    |  4 ++--
 include/linux/iomap.h  |  4 ++--
 7 files changed, 56 insertions(+), 28 deletions(-)