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Do not iterate through filesystems unnecessarily

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Currently, when attempting to list snapshots ZFS may do a lot of
extra work checking child datasets. This is because the code does
not realize that it will not be able to reach any snapshots
contained within snapshots that are at the depth limit since the
snapshots of those datasets are counted as an additional layer
deeper. This patch corrects this issue.

In addition, this patch adds the ability to do perform the commands:

$ zfs list -t snapshot <dataset>
$ zfs get -t snapshot <prop> <dataset>

as a convenient way to list out properties of all snapshots of a
given dataset without having to use the depth limit.

Reviewed-by: Alek Pinchuk <apinchuk@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8539
This commit is contained in:
Tom Caputi 2019-04-01 14:58:59 -04:00 committed by Brian Behlendorf
parent e03b25a564
commit df583073eb
4 changed files with 45 additions and 6 deletions
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25
cmd/zfs/zfs_iter.c
View File

@ -134,16 +134,31 @@ zfs_callback(zfs_handle_t *zhp, void *data)
((cb->cb_flags & ZFS_ITER_DEPTH_LIMIT) == 0 ||
cb->cb_depth < cb->cb_depth_limit)) {
cb->cb_depth++;
if (zfs_get_type(zhp) == ZFS_TYPE_FILESYSTEM)
/*
* If we are not looking for filesystems, we don't need to
* recurse into filesystems when we are at our depth limit.
*/
if ((cb->cb_depth < cb->cb_depth_limit ||
(cb->cb_flags & ZFS_ITER_DEPTH_LIMIT) == 0 ||
(cb->cb_types &
(ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME))) &&
zfs_get_type(zhp) == ZFS_TYPE_FILESYSTEM) {
(void) zfs_iter_filesystems(zhp, zfs_callback, data);
}
if (((zfs_get_type(zhp) & (ZFS_TYPE_SNAPSHOT |
ZFS_TYPE_BOOKMARK)) == 0) && include_snaps)
ZFS_TYPE_BOOKMARK)) == 0) && include_snaps) {
(void) zfs_iter_snapshots(zhp,
(cb->cb_flags & ZFS_ITER_SIMPLE) != 0, zfs_callback,
data, 0, 0);
(cb->cb_flags & ZFS_ITER_SIMPLE) != 0,
zfs_callback, data, 0, 0);
}
if (((zfs_get_type(zhp) & (ZFS_TYPE_SNAPSHOT |
ZFS_TYPE_BOOKMARK)) == 0) && include_bmarks)
ZFS_TYPE_BOOKMARK)) == 0) && include_bmarks) {
(void) zfs_iter_bookmarks(zhp, zfs_callback, data);
}
cb->cb_depth--;
}

20
cmd/zfs/zfs_main.c
View File

@ -1922,6 +1922,16 @@ zfs_do_get(int argc, char **argv)
fields = argv[0];
/*
* Handle users who want to get all snapshots of the current
* dataset (ex. 'zfs get -t snapshot refer <dataset>').
*/
if (types == ZFS_TYPE_SNAPSHOT &&
(flags & ZFS_ITER_RECURSE) == 0 && limit == 0) {
flags |= (ZFS_ITER_DEPTH_LIMIT | ZFS_ITER_RECURSE);
limit = 1;
}
if (zprop_get_list(g_zfs, fields, &cb.cb_proplist, ZFS_TYPE_DATASET)
!= 0)
usage(B_FALSE);
@ -3416,6 +3426,16 @@ zfs_do_list(int argc, char **argv)
if (strcmp(fields, "space") == 0 && types_specified == B_FALSE)
types &= ~ZFS_TYPE_SNAPSHOT;
/*
* Handle users who want to list all snapshots of the current
* dataset (ex. 'zfs list -t snapshot <dataset>').
*/
if (types == ZFS_TYPE_SNAPSHOT &&
(flags & ZFS_ITER_RECURSE) == 0 && limit == 0) {
flags |= (ZFS_ITER_DEPTH_LIMIT | ZFS_ITER_RECURSE);
limit = 1;
}
/*
* If the user specifies '-o all', the zprop_get_list() doesn't
* normally include the name of the dataset. For 'zfs list', we always

1
tests/zfs-tests/include/libtest.shlib
View File

@ -2594,7 +2594,6 @@ function verify_opt_p_ops
"when ops is $ops."
fi
log_must datasetexists $dataset
log_mustnot snapexists $dataset
;;
*)
log_fail "$ops is not supported."

5
tests/zfs-tests/tests/functional/cli_root/zfs_get/zfs_get_009_pos.ksh
View File

@ -87,5 +87,10 @@ for dp in ${depth_array[@]}; do
(( old_val=dp ))
done
# Ensure 'zfs get -t snapshot <dataset>' works as though -d 1 was specified
log_must eval "zfs get -H -t snapshot -o name creation $DEPTH_FS > $DEPTH_OUTPUT"
log_must eval "zfs get -H -t snapshot -d 1 -o name creation $DEPTH_FS > $EXPECT_OUTPUT"
log_must diff $DEPTH_OUTPUT $EXPECT_OUTPUT
log_pass "'zfs get -d <n>' should get expected output."