On 8 Sep 2008, at 20:55, Darren Reed <Darren.Reed at Sun.COM> wrote:
> In the current design of zfs(1m), nearly all of the operations are
> limited
> to working on a single filesystem at a time. This places some
> limitations
> on the usability of zfs(1m) when using it with scripts. For example,
> you
> cannot do:
>
> # zfs list -H -o origin | egrep -v '^\-$' | xargs zfs destroy
That's why 'xargs -l' exists. :-)
However, I see nothing wrong with what you're suggesting.
>
>
> Instead, you need to do this:
>
> # zfs list -H -o origin | egrep -v '^\-$' | sh -c 'while read i; do
> zfs destroy "$i"; done'
>
> (because not everyone uses sh as their shell...)
>
> As an experiment, I modified zfs_main.c to allow destroy to work in
> a manner that is conducive to being used with xargs - patches
> attached.
>
> It's a relatively simple change but there are important questions,
> such
> as does it fail on the first error or continue on, etc.
>
> But I'm sure there was a reason why it was designed and implemented
> the way it is rather than with what my patch suggests?
>
> Darren
>
>
> diff -r 340e8fdced81 usr/src/cmd/zfs/zfs_main.c
> --- a/usr/src/cmd/zfs/zfs_main.c Thu Sep 04 14:02:34 2008 -0700
> +++ b/usr/src/cmd/zfs/zfs_main.c Mon Sep 08 17:45:36 2008 -0700
> @@ -77,6 +77,20 @@
> static int zfs_do_promote(int argc, char **argv);
> static int zfs_do_allow(int argc, char **argv);
> static int zfs_do_unallow(int argc, char **argv);
> +
> +typedef struct destroy_cbdata {
> + boolean_t cb_first;
> + int cb_force;
> + int cb_recurse;
> + int cb_error;
> + int cb_needforce;
> + int cb_doclones;
> + boolean_t cb_closezhp;
> + zfs_handle_t *cb_target;
> + char *cb_snapname;
> +} destroy_cbdata_t;
> +
> +static int zfs_destroy_filesystem(destroy_cbdata_t *cbp, char
> *fsname);
>
> /*
> * Enable a reasonable set of defaults for libumem debugging on
> DEBUG builds.
> @@ -746,17 +760,6 @@
> * and refuse to destroy a dataset that has any dependents. A
> dependent can
> * either be a child, or a clone of a child.
> */
> -typedef struct destroy_cbdata {
> - boolean_t cb_first;
> - int cb_force;
> - int cb_recurse;
> - int cb_error;
> - int cb_needforce;
> - int cb_doclones;
> - boolean_t cb_closezhp;
> - zfs_handle_t *cb_target;
> - char *cb_snapname;
> -} destroy_cbdata_t;
>
> /*
> * Check for any dependents based on the '-r' or '-R' flags.
> @@ -886,8 +889,7 @@
> {
> destroy_cbdata_t cb = { 0 };
> int c;
> - zfs_handle_t *zhp;
> - char *cp;
> + int idx;
>
> /* check options */
> while ((c = getopt(argc, argv, "frR")) != -1) {
> @@ -918,27 +920,36 @@
> (void) fprintf(stderr, gettext("missing path argument\n"));
> usage(B_FALSE);
> }
> - if (argc > 1) {
> - (void) fprintf(stderr, gettext("too many arguments\n"));
> - usage(B_FALSE);
> - }
>
> /*
> * If we are doing recursive destroy of a snapshot, then the
> * named snapshot may not exist. Go straight to libzfs.
> */
> - if (cb.cb_recurse && (cp = strchr(argv[0], '@'))) {
> + for (idx = 0; idx < argc; idx++)
> + if (zfs_destroy_filesystem(&cb, argv[idx]))
> + return (1);
> +
> + return (0);
> +}
> +
> +static int
> +zfs_destroy_filesystem(destroy_cbdata_t *cbp, char *fsname)
> +{
> + char *cp;
> + zfs_handle_t *zhp;
> +
> + if (cbp->cb_recurse && (cp = strchr(fsname, '@'))) {
> int ret;
>
> *cp = '\0';
> - if ((zhp = zfs_open(g_zfs, argv[0], ZFS_TYPE_DATASET)) ==
> NULL)
> + if ((zhp = zfs_open(g_zfs, fsname, ZFS_TYPE_DATASET)) ==
> NULL)
> return (1);
> *cp = '@';
> cp++;
>
> - if (cb.cb_doclones) {
> - cb.cb_snapname = cp;
> - if (destroy_snap_clones(zhp, &cb) != 0) {
> + if (cbp->cb_doclones) {
> + cbp->cb_snapname = cp;
> + if (destroy_snap_clones(zhp, cbp) != 0) {
> zfs_close(zhp);
> return (1);
> }
> @@ -955,15 +966,15 @@
>
>
> /* Open the given dataset */
> - if ((zhp = zfs_open(g_zfs, argv[0], ZFS_TYPE_DATASET)) == NULL)
> - return (1);
> -
> - cb.cb_target = zhp;
> + if ((zhp = zfs_open(g_zfs, fsname, ZFS_TYPE_DATASET)) == NULL)
> + return (1);
> +
> + cbp->cb_target = zhp;
>
> /*
> * Perform an explicit check for pools before going any further.
> */
> - if (!cb.cb_recurse && strchr(zfs_get_name(zhp), '/') == NULL &&
> + if (!cbp->cb_recurse && strchr(zfs_get_name(zhp), '/') == NULL &&
> zfs_get_type(zhp) == ZFS_TYPE_FILESYSTEM) {
> (void) fprintf(stderr, gettext("cannot destroy '%s': "
> "operation does not apply to pools\n"),
> @@ -980,16 +991,16 @@
> /*
> * Check for any dependents and/or clones.
> */
> - cb.cb_first = B_TRUE;
> - if (!cb.cb_doclones &&
> + cbp->cb_first = B_TRUE;
> + if (!cbp->cb_doclones &&
> zfs_iter_dependents(zhp, B_TRUE, destroy_check_dependent,
> - &cb) != 0) {
> - zfs_close(zhp);
> - return (1);
> - }
> -
> - if (cb.cb_error ||
> - zfs_iter_dependents(zhp, B_FALSE, destroy_callback, &cb) !=
> 0) {
> + cbp) != 0) {
> + zfs_close(zhp);
> + return (1);
> + }
> +
> + if (cbp->cb_error ||
> + zfs_iter_dependents(zhp, B_FALSE, destroy_callback, cbp) !=
> 0) {
> zfs_close(zhp);
> return (1);
> }
> @@ -999,9 +1010,8 @@
> * whether it succeeds or not.
> */
>
> - if (destroy_callback(zhp, &cb) != 0)
> - return (1);
> -
> + if (destroy_callback(zhp, cbp) != 0)
> + return (1);
>
> return (0);
> }
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