From e2b31b58e8777faa51561342d72a5a30127fa4b6 Mon Sep 17 00:00:00 2001 From: Paul Zuchowski <31706010+PaulZ-98@users.noreply.github.com> Date: Thu, 15 Aug 2019 10:27:13 -0400 Subject: [PATCH] Make txg_wait_synced conditional in zfsvfs_teardown The call to txg_wait_synced in zfsvfs_teardown should be made conditional on the objset having dirty data. This can prevent unnecessary txg_wait_synced during some unmount operations. Reviewed-by: Matt Ahrens Reviewed-by: Brian Behlendorf Signed-off-by: Paul Zuchowski Closes #9115 --- module/zfs/zfs_vfsops.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c index 8d728adeae94..af82c7bc4800 100644 --- a/module/zfs/zfs_vfsops.c +++ b/module/zfs/zfs_vfsops.c @@ -1778,8 +1778,17 @@ zfsvfs_teardown(zfsvfs_t *zfsvfs, boolean_t unmounting) * Evict cached data. We must write out any dirty data before * disowning the dataset. */ - if (!zfs_is_readonly(zfsvfs)) + objset_t *os = zfsvfs->z_os; + boolean_t os_dirty = B_FALSE; + for (int t = 0; t < TXG_SIZE; t++) { + if (dmu_objset_is_dirty(os, t)) { + os_dirty = B_TRUE; + break; + } + } + if (!zfs_is_readonly(zfsvfs) && os_dirty) { txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0); + } dmu_objset_evict_dbufs(zfsvfs->z_os); return (0);