zfs/module
Brian Behlendorf 89cd2197b9
Fix buffered/direct/mmap I/O race
When a page is faulted in for memory mapped I/O the page lock
may be dropped before it has been read and marked up to date.
If a buffered read encounters such a page in mappedread() it
must wait until the page has been updated. Failure to do so
will result in a panic on debug builds and incorrect data on
production builds.

The critical part of this change is in mappedread() where pages
which are not up to date are now handled. Additionally, it
includes the following simplifications.

- zfs_getpage() and zfs_fillpage() could be passed an array of
  pages. This could be more efficient if it was used but in
  practice only a single page was ever provided. These
  interfaces were simplified to acknowledge that.

- update_pages() was modified to correctly set the PG_error bit
  on a page when it cannot be read by dmu_read().

- Setting PG_error and PG_uptodate was moved to zfs_fillpage()
  from zpl_readpage_common(). This is consistent with the
  handling in update_pages() and mappedread().

- Minor additional refactoring to comments and variable
  declarations to improve readability.

- Add a test case to exercise concurrent buffered, direct,
  and mmap IO to the same file.

- Reduce the mmap_sync test case default run time.

Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #13608 
Closes #14498
2023-02-23 10:57:24 -08:00
..
avl Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
icp Unify assembly files with macOS 2023-02-06 09:27:55 -08:00
lua x86 asm: Replace .align with .balign 2023-01-24 09:04:39 -08:00
nvpair Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
os Fix buffered/direct/mmap I/O race 2023-02-23 10:57:24 -08:00
unicode Illumos #15286: do_composition() needs sign awareness 2023-01-05 11:16:21 -08:00
zcommon Configure zed's diagnosis engine with vdev properties 2023-01-23 13:14:25 -08:00
zfs Fix NULL pointer dereference in zio_ready() 2023-02-23 10:19:08 -08:00
zstd Resolve WS-2021-0184 vulnerability in zstd 2023-02-02 15:12:51 -08:00
.gitignore FreeBSD: Ignore symlink to i386 includes 2022-08-02 16:34:23 -07:00
Kbuild.in Unify Assembler files between Linux and Windows 2023-01-17 11:09:19 -08:00
Makefile.bsd Cleanup dead spa_boot code 2022-09-13 16:40:10 -07:00
Makefile.in autoconf: use include directives instead of recursing down lib 2022-05-10 10:18:11 -07:00