'zfs send -I' should not require 'hold' permission on src dataset if using 'zfs allow' delegation mechanism

[whoschek]

System information

FreeBSD:
zfs-2.1.14-FreeBSD_gd99134be8 (FreeBSD freebsd 13.3-RELEASE FreeBSD 13.3-RELEASE releng/13.3-n257428-80d2b634ddf0 GENERIC amd64)
zfs-2.2.4-FreeBSD_g256659204 (FreeBSD freebsd 14.1-RELEASE FreeBSD 14.1-RELEASE releng/14.1-n267679-10e31f0946d8 GENERIC amd64)

Linux:
zfs-2.2.5~rc7-noble1 (Ubuntu 24.04)
zfs-2.2.2-0ubuntu9 (Ubuntu 24.04)
zfs-2.1.5-1ubuntu6~22.04.4 (Ubuntu 22.04)

Describe the problem you're observing

In my testing I discovered that, on Linux and FreeBSD, the 'send' permission is sufficient for 'zfs send -i' to succeed if the 'zfs allow' delegation mechanism is used to grant permissions to a non-root user (which is expected), whereas for 'zfs send -I' (note the uppercase I) an additional 'hold' permission is required as well (which isn't expected). Otherwise the following error happens on zfs send -I wb_src/tmp@u1 wb_src/tmp@u3

cannot hold: permission denied

The hold permission should not be required. Presumably, the implementation of 'zfs send' intermittently uses a hold but that should better not bubble up to the level of affecting user level permission requirements.

Interestingly, a version with -i (skip intermediate snapshots) instead of -I (include intermediate snapshots) does not fail:
zfs send -i wb_src/tmp@u1 wb_src/tmp@u3 # does not fail

Describe how to reproduce the problem

Here is a reliable minimal reproducer:

sudo zpool destroy -f wb_src
dd if=/dev/zero of=/tmp/wb_src bs=1024 count=102400  # create empty 100MB test file
sudo zpool create wb_src /tmp/wb_src
sudo zfs create -p -u wb_src/tmp
sudo zfs snapshot wb_src/tmp@u1
sudo zfs snapshot wb_src/tmp@u2
sudo zfs snapshot wb_src/tmp@u3

#sudo zfs allow -u $USER send,hold wb_src # use this to make the 'zfs send' succeed
sudo zfs allow -u $USER send wb_src # use this to make the 'zfs send' fail

#The following command fails with
#cannot hold: permission denied
#cannot send 'wb_src/tmp': permission denied
zfs send -I wb_src/tmp@u1 wb_src/tmp@u3 > /tmp/out

#Interestingly, a version with -i (skip intermediate snapshots) instead of -I (include intermediate snapshots) does not fail:
zfs send -i wb_src/tmp@u1 wb_src/tmp@u3 > /tmp/out # does not fail

The exact versions of zfs/FreeBSD/Linux that were tested are listed above.

Include any warning/errors/backtraces from the system logs