OpenZFS on Linux and FreeBSD
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Christian Schwarz 93e3658035
zvol: call zil_replaying() during replay
zil_replaying(zil, tx) has the side-effect of informing the ZIL that an
entry has been replayed in the (still open) tx.  The ZIL uses that
information to record the replay progress in the ZIL header when that
tx's txg syncs.

ZPL log entries are not idempotent and logically dependent and thus
calling zil_replaying() is necessary for correctness.

For ZVOLs the question of correctness is more nuanced: ZVOL logs only
TX_WRITE and TX_TRUNCATE, both of which are idempotent. Logical
dependencies between two records exist only if the write or discard
request had sync semantics or if the ranges affected by the records
overlap.

Thus, at a first glance, it would be correct to restart replay from
the beginning if we crash before replay completes. But this does not
address the following scenario:
Assume one log record per LWB.
The chain on disk is

    HDR -> 1:W(1, "A") -> 2:W(1, "B") -> 3:W(2, "X") -> 4:W(3, "Z")

where N:W(O, C) represents log entry number N which is a TX_WRITE of C
to offset A.
We replay 1, 2 and 3 in one txg, sync that txg, then crash.
Bit flips corrupt 2, 3, and 4.
We come up again and restart replay from the beginning because
we did not call zil_replaying() during replay.
We replay 1 again, then interpret 2's invalid checksum as the end
of the ZIL chain and call replay done.
The replayed zvol content is "AX".

If we had called zil_replaying() the HDR would have pointed to 3
and our resumed replay would not have replayed anything because
3 was corrupted, resulting in zvol content "BX".

If 3 logically depends on 2 then the replay corrupted the ZVOL_OBJ's
contents.

This patch adds the zil_replaying() calls to the replay functions.
Since the callbacks in the replay function need the zilog_t* pointer
so that they can call zil_replaying() we open the ZIL while
replaying in zvol_create_minor(). We also verify that replay has
been done when on-demand-opening the ZIL on the first modifying
bio.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Christian Schwarz <me@cschwarz.com>
Closes #11667
2021-03-07 09:49:58 -08:00
.github CI: add ubuntu-* functional tests runner 2021-02-02 09:37:23 -08:00
cmd Suppress cppcheck invalidSyntax warninigs 2021-03-05 17:56:35 -08:00
config FreeBSD module --enable-debug --enable-invariants 2021-03-05 12:16:41 -08:00
contrib dracut: Fix race condition between load-key and import 2021-01-26 12:14:22 -08:00
etc zfs-import-{cache,scan}: change condition to FileNotEmpty 2021-02-05 11:25:22 -08:00
include Suppress cppcheck invalidSyntax warninigs 2021-03-05 17:56:35 -08:00
lib Don't bomb out when using keylocation=file:// 2021-03-03 08:28:49 -08:00
man Clarify compressed zfs send/recv behavior 2021-03-07 09:39:16 -08:00
module zvol: call zil_replaying() during replay 2021-03-07 09:49:58 -08:00
rpm Add "compatibility" property for zpool feature sets 2021-02-17 21:30:45 -08:00
scripts Fix error message when zfs module are already unloaded 2021-02-20 20:23:10 -08:00
tests ZTS: Improve cleanup in zpool tests 2021-03-07 09:41:01 -08:00
udev Centralize variable substitution 2020-07-14 17:33:44 -07:00
.editorconfig Add an .editorconfig; document git whitespace settings 2020-01-27 13:32:52 -08:00
.gitignore Add FreeBSD support to OpenZFS 2020-04-14 11:36:28 -07:00
.gitmodules Add zimport.sh compatibility test script 2014-02-21 12:10:31 -08:00
AUTHORS Add zstd support to zfs 2020-08-20 10:30:06 -07:00
CODE_OF_CONDUCT.md Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
COPYRIGHT Fix typos 2020-06-09 21:24:09 -07:00
LICENSE Update build system and packaging 2018-05-29 16:00:33 -07:00
META Linux 5.11 compat: META 2021-02-10 10:11:21 -08:00
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NEWS Fix NEWS file 2020-08-26 21:44:41 -07:00
NOTICE Update build system and packaging 2018-05-29 16:00:33 -07:00
README.md docs: update README's installation link 2020-10-08 09:33:53 -07:00
TEST Remove CI builder customization from TEST 2020-03-16 10:46:03 -07:00
autogen.sh Cause autogen.sh to fail if autoreconf fails 2018-07-06 09:27:37 -07:00
configure.ac FreeBSD module --enable-debug --enable-invariants 2021-03-05 12:16:41 -08:00
copy-builtin Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

README.md

img

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 12-STABLE and 13-CURRENT.