OpenZFS 8605 - zfs channel programs fix zfs.exists

Authored by: Chris Williamson <[email protected]>
Reviewed by: Paul Dagnelie <[email protected]>
Reviewed by: Dan Kimmel <[email protected]>
Reviewed by: Matt Ahrens <[email protected]>
Approved by: Robert Mustacchi <[email protected]>
Ported-by: Don Brady <[email protected]>

zfs.exists() in channel programs doesn't return any result, and should
have a man page entry. This patch corrects zfs.exists so that it
returns a value indicating if the dataset exists or not. It also adds
documentation about it in the man page.

OpenZFS-issue: https://www.illumos.org/issues/8605
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/1e85e111

1 files changed, 12 insertions, 0 deletions

diff --git a/man/man8/zfs-program.8 b/man/man8/zfs-program.8
index d84990ca1..2e4e9587d 100644
--- a/man/man8/zfs-program.8
+++ b/man/man8/zfs-program.8
@@ -289,6 +289,18 @@ msg (string)
 .Bd -ragged -compact -offset "xxxx"
 Debug message to be printed.
 .Ed
+.It Em zfs.exists(dataset)
+Returns true if the given dataset exists, or false if it doesn't.
+A fatal error will be thrown if the dataset is not in the target pool.
+That is, in a channel program running on rpool,
+zfs.exists("rpool/nonexistent_fs") returns false, but
+zfs.exists("somepool/fs_that_may_exist") will error.
+.Pp
+dataset (string)
+.Bd -ragged -compact -offset "xxxx"
+Dataset to check for existence.
+Must be in the target pool.
+.Ed
 .It Em zfs.get_prop(dataset, property)
 Returns two values.
 First, a string, number or table containing the property value for the given