[PATCH 0/3] ovl: make cachestat() work

We were using cachestat() for our internal Virtuozzo cache related tests
and I saw that test behaves wrong on overlayfs, syscall returns all
zeroes instead of any meaningful cache statistics there. Let's fix it
similar to what was done for fadvise().

Signed-off-by: Pavel Tikhomirov <[email protected]>

Pavel Tikhomirov (3):
  fs, mm: add ->cachestat() file operation
  ovl: support cachestat() syscall on overlayfs files
  selftests/cachestat: add an overlayfs test case

 fs/overlayfs/file.c                           | 18 +++++
 include/linux/fs.h                            | 10 +++
 mm/filemap.c                                  | 43 +++++++++--
 .../selftests/cachestat/test_cachestat.c      | 75 ++++++++++++++++++-
 4 files changed, 137 insertions(+), 9 deletions(-)

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2.54.0