Alexander Motin 21bbe7cb67 Improve caching for dbuf prefetches
To avoid read errors with transaction open dmu_tx_check_ioerr()
is used to read everything required in advance.  But there seems
to be a chance for the buffer to evicted from dbuf cache in
between, which result in immediate eviction from ARC, which may
require additional disk read later in a place where error handling
is problematic.

To partially workaround this introduce a new flag DMU_IS_PREFETCH,
relayed to ARC as ARC_FLAG_PREFETCH | ARC_FLAG_PRESCIENT_PREFETCH,
making ARC delay eviction by at least several seconds, or till the
actual read inside the transaction, that will promote it to demand
access.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes #18160
2026-02-04 10:12:32 -08:00
2022-12-22 11:34:28 -08:00
2020-06-09 21:24:09 -07:00
2018-05-29 16:00:33 -07:00
2025-12-10 09:04:24 -08:00
2020-08-26 21:44:41 -07:00
2018-05-29 16:00:33 -07:00
2025-11-03 16:37:58 -08:00
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OpenZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community. This repository contains the code for running OpenZFS on Linux and FreeBSD.

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Official Resources

Installation

Full documentation for installing OpenZFS on your favorite operating system can be found at the Getting Started Page.

Contribute & Develop

We have a separate document with contribution guidelines.

We have a Code of Conduct.

Release

OpenZFS is released under a CDDL license. For more details see the NOTICE, LICENSE and COPYRIGHT files; UCRL-CODE-235197

Supported Kernels

  • The META file contains the officially recognized supported Linux kernel versions.
  • Supported FreeBSD versions are any supported branches and releases starting from 13.0-RELEASE.
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