Kernel checks are the heaviest part of the configure checks. This allows
the results to be cached through the normal autoconf cache.
Since we don't want to reuse cached values for different kernels, but
don't want to discard the entire cache on every kernel, we instead add a
short checksum to kernel config cache keys, based on the version and
path, so the cache can hold results for multiple different kernels.
Sponsored-by: https://despairlabs.com/sponsor/
Signed-off-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
It turns out that approach taken in the original version of the patch
was wrong. So now, we're taking approach in-line with how kernel
actually does it - when sb is being torn down, access to it
is serialized via sb->s_umount rwsem, only when that lock is taken
is it okay to work with s_flags - and the other mistake I was doing
was trying to make SB_ACTIVE work, but apparently the kernel checks
the negative variant - not SB_DYING and not SB_BORN.
Kernels pre-6.6 don't have SB_DYING, but check if sb is hashed
instead.
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
In order to correctly cross-compile, one has to pass ARCH and
CROSS_COMPILE make flags to kernel module build calls. Facilitate this
in the same way as for custom CC flag by recognizing KERNEL_-prefixed
configure environment variables of same name.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Closes#16924
As of kernel v5.8, pin_user_pages* interfaced were introduced. These
interfaces use the FOLL_PIN flag. This is preferred interface now for
Direct I/O requests in the kernel. The reasoning for using this new
interface for Direct I/O requests is explained in the kernel
documenetation:
Documentation/core-api/pin_user_pages.rst
If pin_user_pages_unlocked is available, the all Direct I/O requests
will use this new API to stay uptodate with the kernel API requirements.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#16856
There were checks still in place to verify we could completely use
iov_iter's on the Linux side. All interfaces are available as of kernel
4.18, so there is no reason to check whether we should use that
interface at this point. This PR completely removes the UIO_USERSPACE
type. It also removes the check for the direct_IO interface checks.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#16856
Avoids using fallback_migrate_folio, which starts unnecessary writeback
(leading to BUG in migrate_folio_extra).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: tstabrawa <59430211+tstabrawa@users.noreply.github.com>
Closes#16568Closes#16723
This reverts commit b052035990.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: tstabrawa <59430211+tstabrawa@users.noreply.github.com>
Closes#16568Closes#16723
torvalds/linux@09022bc196 removes the flag, and the corresponding
SetPageError() and ClearPageError() macros, with no replacement offered.
Going back through the upstream history, use of this flag has been
gradually removed over the last year as part of the long tail of
converting everything to folios. Interesting tidbit comments from
torvalds/linux@29e9412b25 and torvalds/linux@420e05d0de suggest that
this flag has not been used meaningfully since page writeback failures
started being recorded in errseq_t instead (the whole "fsyncgate" thing,
~2017, around torvalds/linux@8ed1e46aaf).
Given that, it's possible that since perhaps Linux 4.13 we haven't been
getting anything by setting the flag. I don't know if that's true and/or
if there's something we should be doing instead, but my gut feel is that
its probably fine we only use the page cache as a proxy to allow mmap()
to work, rather than backing IO with it.
As such, I'm expecting that removing this will do no harm, but I'm
leaving it in for older kernels to maintain status quo, and if there is
an overall better way, that is left for a future change.
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#16582
linux/torvalds@11068e0b64 removes it, suggesting this was a always
there as a helper to handle concurrent seeks, which all filesystems now
handle themselves if necessary.
Without looking into the mechanism, I can imagine how it might have been
used, but we have always set it to zero and never read from it,
presumably because we've always tracked per-caller position through the
znode anyway. So I don't see how there can be any functional change for
us by removing it. I've stayed conservative though and left it in for
older kernels, since its clearly not hurting anything there.
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#16582
Linux page migration code won't wait for writeback to complete unless
it needs to call release_folio. Call SetPagePrivate wherever
PageUptodate is set and define .release_folio, to cause
fallback_migrate_folio to wait for us.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: tstabrawa <59430211+tstabrawa@users.noreply.github.com>
Closes#15140Closes#16568
META lists the maximum kernel version we consider to be fully supported.
However, we don't enforce this.
Sometimes we ship experimental patches for a newer kernel than we're
ready to support or, less often, we compile just fine against a newer
kernel. Invariably, something doesn't quite work properly, and it's
difficult for users to understand that they're actually running against
a kernel that we're not yet ready to support.
This commit tries to improve this situation. First, it simply enforces
Linux-Maximum, by having configure bail out if you try to compile
against a newer version that.
Then, it adds the --enable-linux-experimental switch to configure. When
supplied, this disables enforcing the maximum version, allowing the user
to attempt to build against a kernel with version higher than
Linux-Maximum.
Finally, if the switch is supplied _and_ configure is run against a
higher kernel version, it shows a big warning message when configure
finishes, and defines HAVE_LINUX_EXPERIMENTAL for the build. This allows
us to add code to modify runtime behaviour as well.
Reviewed-by: Robert Evans <evansr@google.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#15986
get_user_pages_unlocked() had stabilised by 4.9.
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#16479
