[v2,0/2] filemap: skip write and wait if end offset precedes start

Message

Brian Foster Nov. 28, 2022, 3:56 p.m. UTC

Hi all,

Here's a v2 of a prospective fix for the odd write and wait behavior
described in the patch 1 commit log. Technically patch 1 could simply
remove the check rather than lift it into the callers, but this seemed a
bit more user friendly to me. Patch 2 is appended after observation that
fadvise() interacted poorly with the v1 patch. This is no longer a
problem with v2, making patch 2 purely a cleanup.

This series survived both fstests and ltp regression runs without
observable problems. I had (end < start) warning checks in each relevant
function, with fadvise() being the only caller that triggered them. That
said, I dropped the warnings after testing because there seemed to much
potential for noise from the various other callers.

Brian

v2:
- Remove check from fdatawait rather than add to fdatawrite (as in v1).
  Lift into file[map]_write_and_wait_range() helpers.
- Added patch 2.
v1: https://lore.kernel.org/linux-mm/[e-mail]/

Brian Foster (2):
  filemap: skip write and wait if end offset precedes start
  mm/fadvise: use LLONG_MAX instead of -1 for eof

 mm/fadvise.c | 2 +-
 mm/filemap.c | 9 ++++++---
 2 files changed, 7 insertions(+), 4 deletions(-)