mirror_zfs/cmd
Serapheim Dimitropoulos 425d3237ee Get rid of space_map_update() for ms_synced_length
Initially, metaslabs and space maps used to be the same thing
in ZFS. Later, we started differentiating them by referring
to the space map as the on-disk state of the metaslab, making
the metaslab a higher-level concept that is metadata that deals
with space accounting. Today we've managed to split that code
furthermore, with the space map being its own on-disk data
structure used in areas of ZFS besides metaslabs (e.g. the
vdev-wide space maps used for zpool checkpoint or vdev removal
features).

This patch refactors the space map code to further split the
space map code from the metaslab code. It does so by getting
rid of the idea that the space map can have a different in-core
and on-disk length (sm_length vs smp_length) which is something
that is only used for the metaslab code, and other consumers
of space maps just have to deal with. Instead, this patch
introduces changes that move the old in-core length of the
metaslab's space map to the metaslab structure itself (see
ms_synced_length field) while making the space map code only
care about the actual space map's length on-disk.

The result of this is that space map consumers no longer have
to deal with syncing two different lengths for the same
structure (e.g. space_map_update() goes away) while metaslab
specific behavior stays within the metaslab code. Specifically,
the ms_synced_length field keeps track of the amount of data
metaslab_load() can read from the metaslab's space map while
working concurrently with metaslab_sync() that may be
appending to that same space map.

As a side note, the patch also adds a few comments around
the metaslab code documenting some assumptions and expected
behavior.

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8328
2019-02-12 10:38:11 -08:00
..
arc_summary pyzfs: python3 support (build system) 2019-01-06 10:39:41 -08:00
arcstat pyzfs: python3 support (build system) 2019-01-06 10:39:41 -08:00
dbufstat pyzfs: python3 support (build system) 2019-01-06 10:39:41 -08:00
fsck_zfs Add /sbin/fsck.zfs helper 2013-01-09 16:54:58 -08:00
mount_zfs Add libzutil for libzfs or libzpool consumers 2018-11-05 11:22:33 -08:00
raidz_test Support -fsanitize=address with --enable-asan 2018-01-10 10:49:27 -08:00
vdev_id Add enclosure_symlinks option to vdev_id 2018-12-14 17:27:49 -08:00
zdb Get rid of space_map_update() for ms_synced_length 2019-02-12 10:38:11 -08:00
zed shellcheck pass 2019-02-04 09:07:19 -08:00
zfs zfs userspace dumps core when used on ZVOLs 2019-01-25 09:47:52 -08:00
zgenhostid Add zgenhostid utility script 2017-07-25 13:22:03 -04:00
zhack Add libzutil for libzfs or libzpool consumers 2018-11-05 11:22:33 -08:00
zinject Add libzutil for libzfs or libzpool consumers 2018-11-05 11:22:33 -08:00
zpool shellcheck pass 2019-02-04 09:07:19 -08:00
zstreamdump zstreamdump dumps core printing truncated nvlist 2018-09-18 09:43:09 -07:00
ztest GCC 9.0: Fix ztest "directive argument is not a nul-terminated string" 2019-01-28 10:11:45 -08:00
zvol_id Fedora 28: Fix misc bounds check compiler warnings 2018-04-04 10:16:47 -07:00
Makefile.am Retire legacy test infrastructure 2017-08-15 17:26:38 -07:00