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Speed up 'zfs list -t snapshot -o name -s name'

FreeBSD #xxx:  Dramatically optimize listing snapshots when user
requests only snapshot names and wants to sort them by name, ie.
when executes:

  # zfs list -t snapshot -o name -s name

Because only name is needed we don't have to read all snapshot
properties.

Below you can find how long does it take to list 34509 snapshots
from a single disk pool before and after this change with cold and
warm cache:

    before:

        # time zfs list -t snapshot -o name -s name > /dev/null
        cold cache: 525s
        warm cache: 218s

    after:

        # time zfs list -t snapshot -o name -s name > /dev/null
        cold cache: 1.7s
        warm cache: 1.1s

NOTE: This patch only appears in FreeBSD.  If/when Illumos picks up
the change we may want to drop this patch and adopt their version.
However, for now this addresses a real issue.

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #450
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1 parent 74497b7 commit 0cee24064a79f9c01fc4521543c37acea538405f @pjd pjd committed with behlendorf May 29, 2012
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30 cmd/zfs/zfs_iter.c
@@ -20,6 +20,7 @@
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012 Pawel Jakub Dawidek <pawel@dawidek.net>.
*/
#include <libintl.h>
@@ -129,8 +130,11 @@ zfs_callback(zfs_handle_t *zhp, void *data)
cb->cb_depth++;
if (zfs_get_type(zhp) == ZFS_TYPE_FILESYSTEM)
(void) zfs_iter_filesystems(zhp, zfs_callback, data);
- if ((zfs_get_type(zhp) != ZFS_TYPE_SNAPSHOT) && include_snaps)
- (void) zfs_iter_snapshots(zhp, zfs_callback, data);
+ if ((zfs_get_type(zhp) != ZFS_TYPE_SNAPSHOT) && include_snaps) {
+ (void) zfs_iter_snapshots(zhp,
+ (cb->cb_flags & ZFS_ITER_SIMPLE) != 0, zfs_callback,
+ data);
+ }
cb->cb_depth--;
}
@@ -184,6 +188,13 @@ zfs_free_sort_columns(zfs_sort_column_t *sc)
}
}
+int
+zfs_sort_only_by_name(const zfs_sort_column_t *sc)
+{
+ return (sc != NULL && sc->sc_next == NULL &&
+ sc->sc_prop == ZFS_PROP_NAME);
+}
+
/* ARGSUSED */
static int
zfs_compare(const void *larg, const void *rarg, void *unused)
@@ -224,7 +235,13 @@ zfs_compare(const void *larg, const void *rarg, void *unused)
lcreate = zfs_prop_get_int(l, ZFS_PROP_CREATETXG);
rcreate = zfs_prop_get_int(r, ZFS_PROP_CREATETXG);
- if (lcreate < rcreate)
+ /*
+ * Both lcreate and rcreate being 0 means we don't have
+ * properties and we should compare full name.
+ */
+ if (lcreate == 0 && rcreate == 0)
+ ret = strcmp(lat + 1, rat + 1);
+ else if (lcreate < rcreate)
ret = -1;
else if (lcreate > rcreate)
ret = 1;
@@ -290,7 +307,14 @@ zfs_sort(const void *larg, const void *rarg, void *data)
if (rvalid)
verify(nvlist_lookup_string(rval,
ZPROP_VALUE, &rstr) == 0);
+ } else if (psc->sc_prop == ZFS_PROP_NAME) {
+ lvalid = rvalid = B_TRUE;
+
+ (void) strlcpy(lbuf, zfs_get_name(l), sizeof(lbuf));
+ (void) strlcpy(rbuf, zfs_get_name(r), sizeof(rbuf));
+ lstr = lbuf;
+ rstr = rbuf;
} else if (zfs_prop_is_string(psc->sc_prop)) {
lvalid = (zfs_prop_get(l, psc->sc_prop, lbuf,
sizeof (lbuf), NULL, NULL, 0, B_TRUE) == 0);
View
2 cmd/zfs/zfs_iter.h
@@ -43,11 +43,13 @@ typedef struct zfs_sort_column {
#define ZFS_ITER_PROP_LISTSNAPS (1 << 2)
#define ZFS_ITER_DEPTH_LIMIT (1 << 3)
#define ZFS_ITER_RECVD_PROPS (1 << 4)
+#define ZFS_ITER_SIMPLE (1 << 5)
int zfs_for_each(int, char **, int options, zfs_type_t,
zfs_sort_column_t *, zprop_list_t **, int, zfs_iter_f, void *);
int zfs_add_sort_column(zfs_sort_column_t **, const char *, boolean_t);
void zfs_free_sort_columns(zfs_sort_column_t *);
+int zfs_sort_only_by_name(const zfs_sort_column_t *);
#ifdef __cplusplus
}
View
14 cmd/zfs/zfs_main.c
@@ -2650,7 +2650,12 @@ print_dataset(zfs_handle_t *zhp, zprop_list_t *pl, boolean_t scripted)
first = B_FALSE;
}
- if (pl->pl_prop != ZPROP_INVAL) {
+ if (pl->pl_prop == ZFS_PROP_NAME) {
+ (void) strlcpy(property, zfs_get_name(zhp),
+ sizeof(property));
+ propstr = property;
+ right_justify = zfs_prop_align_right(pl->pl_prop);
+ } else if (pl->pl_prop != ZPROP_INVAL) {
if (zfs_prop_get(zhp, pl->pl_prop, property,
sizeof (property), NULL, NULL, 0, B_FALSE) != 0)
propstr = "-";
@@ -2811,6 +2816,13 @@ zfs_do_list(int argc, char **argv)
fields = default_fields;
/*
+ * If we are only going to list snapshot names and sort by name,
+ * then we can use faster version.
+ */
+ if (strcmp(fields, "name") == 0 && zfs_sort_only_by_name(sortcol))
+ flags |= ZFS_ITER_SIMPLE;
+
+ /*
* If "-o space" and no types were specified, don't display snapshots.
*/
if (strcmp(fields, "space") == 0 && types_specified == B_FALSE)
View
2 include/libzfs.h
@@ -516,7 +516,7 @@ extern int zfs_iter_root(libzfs_handle_t *, zfs_iter_f, void *);
extern int zfs_iter_children(zfs_handle_t *, zfs_iter_f, void *);
extern int zfs_iter_dependents(zfs_handle_t *, boolean_t, zfs_iter_f, void *);
extern int zfs_iter_filesystems(zfs_handle_t *, zfs_iter_f, void *);
-extern int zfs_iter_snapshots(zfs_handle_t *, zfs_iter_f, void *);
+extern int zfs_iter_snapshots(zfs_handle_t *, boolean_t, zfs_iter_f, void *);
extern int zfs_iter_snapshots_sorted(zfs_handle_t *, zfs_iter_f, void *);
typedef struct get_all_cb {
View
3 include/sys/zfs_ioctl.h
@@ -286,7 +286,8 @@ typedef struct zfs_cmd {
boolean_t zc_temphold;
uint64_t zc_action_handle;
int zc_cleanup_fd;
- uint8_t zc_pad[4]; /* alignment */
+ uint8_t zc_simple;
+ uint8_t zc_pad[3]; /* alignment */
uint64_t zc_sendobj;
uint64_t zc_fromobj;
uint64_t zc_createtxg;
View
41 lib/libzfs/libzfs_dataset.c
@@ -23,6 +23,7 @@
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2010 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright (c) 2012 Pawel Jakub Dawidek <pawel@dawidek.net>.
*/
#include <ctype.h>
@@ -480,6 +481,23 @@ make_dataset_handle_zc(libzfs_handle_t *hdl, zfs_cmd_t *zc)
return (zhp);
}
+static zfs_handle_t *
+make_dataset_simple_handle_zc(zfs_handle_t *pzhp, zfs_cmd_t *zc)
+{
+ zfs_handle_t *zhp = calloc(sizeof (zfs_handle_t), 1);
+
+ if (zhp == NULL)
+ return (NULL);
+
+ zhp->zfs_hdl = pzhp->zfs_hdl;
+ (void) strlcpy(zhp->zfs_name, zc->zc_name, sizeof (zhp->zfs_name));
+ zhp->zfs_head_type = pzhp->zfs_type;
+ zhp->zfs_type = ZFS_TYPE_SNAPSHOT;
+ zhp->zpool_hdl = zpool_handle(zhp);
+
+ return (zhp);
+}
+
/*
* Opens the given snapshot, filesystem, or volume. The 'types'
* argument is a mask of acceptable types. The function will print an
@@ -2518,7 +2536,8 @@ zfs_iter_filesystems(zfs_handle_t *zhp, zfs_iter_f func, void *data)
* Iterate over all snapshots
*/
int
-zfs_iter_snapshots(zfs_handle_t *zhp, zfs_iter_f func, void *data)
+zfs_iter_snapshots(zfs_handle_t *zhp, boolean_t simple, zfs_iter_f func,
+ void *data)
{
zfs_cmd_t zc = { "\0", "\0", "\0", "\0", 0 };
zfs_handle_t *nzhp;
@@ -2527,15 +2546,19 @@ zfs_iter_snapshots(zfs_handle_t *zhp, zfs_iter_f func, void *data)
if (zhp->zfs_type == ZFS_TYPE_SNAPSHOT)
return (0);
+ zc.zc_simple = simple;
+
if (zcmd_alloc_dst_nvlist(zhp->zfs_hdl, &zc, 0) != 0)
return (-1);
while ((ret = zfs_do_list_ioctl(zhp, ZFS_IOC_SNAPSHOT_LIST_NEXT,
&zc)) == 0) {
- if ((nzhp = make_dataset_handle_zc(zhp->zfs_hdl,
- &zc)) == NULL) {
+ if (simple)
+ nzhp = make_dataset_simple_handle_zc(zhp, &zc);
+ else
+ nzhp = make_dataset_handle_zc(zhp->zfs_hdl, &zc);
+ if (nzhp == NULL)
continue;
- }
if ((ret = func(nzhp, data)) != 0) {
zcmd_free_nvlists(&zc);
@@ -2557,7 +2580,7 @@ zfs_iter_children(zfs_handle_t *zhp, zfs_iter_f func, void *data)
if ((ret = zfs_iter_filesystems(zhp, func, data)) != 0)
return (ret);
- return (zfs_iter_snapshots(zhp, func, data));
+ return (zfs_iter_snapshots(zhp, B_FALSE, func, data));
}
/*
@@ -3287,7 +3310,7 @@ zfs_promote(zfs_handle_t *zhp)
return (-1);
(void) zfs_prop_get(pzhp, ZFS_PROP_MOUNTPOINT, pd.cb_mountpoint,
sizeof (pd.cb_mountpoint), NULL, NULL, 0, FALSE);
- ret = zfs_iter_snapshots(pzhp, promote_snap_cb, &pd);
+ ret = zfs_iter_snapshots(pzhp, B_FALSE, promote_snap_cb, &pd);
if (ret != 0) {
zfs_close(pzhp);
return (-1);
@@ -3302,7 +3325,8 @@ zfs_promote(zfs_handle_t *zhp)
if (ret != 0) {
int save_errno = errno;
- (void) zfs_iter_snapshots(pzhp, promote_snap_done_cb, &pd);
+ (void) zfs_iter_snapshots(pzhp, B_FALSE, promote_snap_done_cb,
+ &pd);
zfs_close(pzhp);
switch (save_errno) {
@@ -3321,7 +3345,8 @@ zfs_promote(zfs_handle_t *zhp)
return (zfs_standard_error(hdl, save_errno, errbuf));
}
} else {
- (void) zfs_iter_snapshots(zhp, promote_snap_done_cb, &pd);
+ (void) zfs_iter_snapshots(zhp, B_FALSE, promote_snap_done_cb,
+ &pd);
}
zfs_close(pzhp);
View
6 lib/libzfs/libzfs_sendrecv.c
@@ -21,6 +21,8 @@
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012 Pawel Jakub Dawidek <pawel@dawidek.net>.
+ * All rights reserved
*/
#include <assert.h>
@@ -717,7 +719,7 @@ send_iterate_fs(zfs_handle_t *zhp, void *arg)
sd->parent_fromsnap_guid = 0;
VERIFY(0 == nvlist_alloc(&sd->parent_snaps, NV_UNIQUE_NAME, 0));
VERIFY(0 == nvlist_alloc(&sd->snapprops, NV_UNIQUE_NAME, 0));
- (void) zfs_iter_snapshots(zhp, send_iterate_snap, sd);
+ (void) zfs_iter_snapshots(zhp, B_FALSE, send_iterate_snap, sd);
VERIFY(0 == nvlist_add_nvlist(nvfs, "snaps", sd->parent_snaps));
VERIFY(0 == nvlist_add_nvlist(nvfs, "snapprops", sd->snapprops));
nvlist_free(sd->parent_snaps);
@@ -843,7 +845,7 @@ zfs_iter_snapshots_sorted(zfs_handle_t *zhp, zfs_iter_f callback, void *data)
avl_create(&avl, zfs_snapshot_compare,
sizeof (zfs_node_t), offsetof(zfs_node_t, zn_avlnode));
- ret = zfs_iter_snapshots(zhp, zfs_sort_snaps, &avl);
+ ret = zfs_iter_snapshots(zhp, B_FALSE, zfs_sort_snaps, &avl);
for (node = avl_first(&avl); node != NULL; node = AVL_NEXT(&avl, node))
ret |= callback(node->zn_handle, data);
View
5 module/zfs/zfs_ioctl.c
@@ -21,6 +21,7 @@
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Portions Copyright 2011 Martin Matuska
+ * Portions Copyright 2012 Pawel Jakub Dawidek <pawel@dawidek.net>
* Copyright (c) 2012, Joyent, Inc. All rights reserved.
*/
@@ -1973,7 +1974,7 @@ zfs_ioc_snapshot_list_next(zfs_cmd_t *zc)
int error;
top:
- if (zc->zc_cookie == 0)
+ if (zc->zc_cookie == 0 && !zc->zc_simple)
(void) dmu_objset_find(zc->zc_name, dmu_objset_prefetch,
NULL, DS_FIND_SNAPSHOTS);
@@ -1995,7 +1996,7 @@ zfs_ioc_snapshot_list_next(zfs_cmd_t *zc)
zc->zc_name + strlen(zc->zc_name), &zc->zc_obj, &zc->zc_cookie,
NULL);
- if (error == 0) {
+ if (error == 0 && !zc->zc_simple) {
dsl_dataset_t *ds;
dsl_pool_t *dp = os->os_dsl_dataset->ds_dir->dd_pool;

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