freebsd-dev/module/zfs/space_map.c
2010-05-28 13:45:14 -07:00

617 lines
15 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/dmu.h>
#include <sys/zio.h>
#include <sys/space_map.h>
/*
* Space map routines.
* NOTE: caller is responsible for all locking.
*/
static int
space_map_seg_compare(const void *x1, const void *x2)
{
const space_seg_t *s1 = x1;
const space_seg_t *s2 = x2;
if (s1->ss_start < s2->ss_start) {
if (s1->ss_end > s2->ss_start)
return (0);
return (-1);
}
if (s1->ss_start > s2->ss_start) {
if (s1->ss_start < s2->ss_end)
return (0);
return (1);
}
return (0);
}
void
space_map_create(space_map_t *sm, uint64_t start, uint64_t size, uint8_t shift,
kmutex_t *lp)
{
bzero(sm, sizeof (*sm));
cv_init(&sm->sm_load_cv, NULL, CV_DEFAULT, NULL);
avl_create(&sm->sm_root, space_map_seg_compare,
sizeof (space_seg_t), offsetof(struct space_seg, ss_node));
sm->sm_start = start;
sm->sm_size = size;
sm->sm_shift = shift;
sm->sm_lock = lp;
}
void
space_map_destroy(space_map_t *sm)
{
ASSERT(!sm->sm_loaded && !sm->sm_loading);
VERIFY3U(sm->sm_space, ==, 0);
avl_destroy(&sm->sm_root);
cv_destroy(&sm->sm_load_cv);
}
void
space_map_add(space_map_t *sm, uint64_t start, uint64_t size)
{
avl_index_t where;
space_seg_t ssearch, *ss_before, *ss_after, *ss;
uint64_t end = start + size;
int merge_before, merge_after;
ASSERT(MUTEX_HELD(sm->sm_lock));
VERIFY(size != 0);
VERIFY3U(start, >=, sm->sm_start);
VERIFY3U(end, <=, sm->sm_start + sm->sm_size);
VERIFY(sm->sm_space + size <= sm->sm_size);
VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);
VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);
ssearch.ss_start = start;
ssearch.ss_end = end;
ss = avl_find(&sm->sm_root, &ssearch, &where);
if (ss != NULL && ss->ss_start <= start && ss->ss_end >= end) {
zfs_panic_recover("zfs: allocating allocated segment"
"(offset=%llu size=%llu)\n",
(longlong_t)start, (longlong_t)size);
return;
}
/* Make sure we don't overlap with either of our neighbors */
VERIFY(ss == NULL);
ss_before = avl_nearest(&sm->sm_root, where, AVL_BEFORE);
ss_after = avl_nearest(&sm->sm_root, where, AVL_AFTER);
merge_before = (ss_before != NULL && ss_before->ss_end == start);
merge_after = (ss_after != NULL && ss_after->ss_start == end);
if (merge_before && merge_after) {
avl_remove(&sm->sm_root, ss_before);
if (sm->sm_pp_root) {
avl_remove(sm->sm_pp_root, ss_before);
avl_remove(sm->sm_pp_root, ss_after);
}
ss_after->ss_start = ss_before->ss_start;
kmem_free(ss_before, sizeof (*ss_before));
ss = ss_after;
} else if (merge_before) {
ss_before->ss_end = end;
if (sm->sm_pp_root)
avl_remove(sm->sm_pp_root, ss_before);
ss = ss_before;
} else if (merge_after) {
ss_after->ss_start = start;
if (sm->sm_pp_root)
avl_remove(sm->sm_pp_root, ss_after);
ss = ss_after;
} else {
ss = kmem_alloc(sizeof (*ss), KM_SLEEP);
ss->ss_start = start;
ss->ss_end = end;
avl_insert(&sm->sm_root, ss, where);
}
if (sm->sm_pp_root)
avl_add(sm->sm_pp_root, ss);
sm->sm_space += size;
}
void
space_map_remove(space_map_t *sm, uint64_t start, uint64_t size)
{
avl_index_t where;
space_seg_t ssearch, *ss, *newseg;
uint64_t end = start + size;
int left_over, right_over;
ASSERT(MUTEX_HELD(sm->sm_lock));
VERIFY(size != 0);
VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);
VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);
ssearch.ss_start = start;
ssearch.ss_end = end;
ss = avl_find(&sm->sm_root, &ssearch, &where);
/* Make sure we completely overlap with someone */
if (ss == NULL) {
zfs_panic_recover("zfs: freeing free segment "
"(offset=%llu size=%llu)",
(longlong_t)start, (longlong_t)size);
return;
}
VERIFY3U(ss->ss_start, <=, start);
VERIFY3U(ss->ss_end, >=, end);
VERIFY(sm->sm_space - size <= sm->sm_size);
left_over = (ss->ss_start != start);
right_over = (ss->ss_end != end);
if (sm->sm_pp_root)
avl_remove(sm->sm_pp_root, ss);
if (left_over && right_over) {
newseg = kmem_alloc(sizeof (*newseg), KM_SLEEP);
newseg->ss_start = end;
newseg->ss_end = ss->ss_end;
ss->ss_end = start;
avl_insert_here(&sm->sm_root, newseg, ss, AVL_AFTER);
if (sm->sm_pp_root)
avl_add(sm->sm_pp_root, newseg);
} else if (left_over) {
ss->ss_end = start;
} else if (right_over) {
ss->ss_start = end;
} else {
avl_remove(&sm->sm_root, ss);
kmem_free(ss, sizeof (*ss));
ss = NULL;
}
if (sm->sm_pp_root && ss != NULL)
avl_add(sm->sm_pp_root, ss);
sm->sm_space -= size;
}
boolean_t
space_map_contains(space_map_t *sm, uint64_t start, uint64_t size)
{
avl_index_t where;
space_seg_t ssearch, *ss;
uint64_t end = start + size;
ASSERT(MUTEX_HELD(sm->sm_lock));
VERIFY(size != 0);
VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);
VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);
ssearch.ss_start = start;
ssearch.ss_end = end;
ss = avl_find(&sm->sm_root, &ssearch, &where);
return (ss != NULL && ss->ss_start <= start && ss->ss_end >= end);
}
void
space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)
{
space_seg_t *ss;
void *cookie = NULL;
ASSERT(MUTEX_HELD(sm->sm_lock));
while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
if (func != NULL)
func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);
kmem_free(ss, sizeof (*ss));
}
sm->sm_space = 0;
}
void
space_map_walk(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)
{
space_seg_t *ss;
ASSERT(MUTEX_HELD(sm->sm_lock));
for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))
func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);
}
/*
* Wait for any in-progress space_map_load() to complete.
*/
void
space_map_load_wait(space_map_t *sm)
{
ASSERT(MUTEX_HELD(sm->sm_lock));
while (sm->sm_loading) {
ASSERT(!sm->sm_loaded);
cv_wait(&sm->sm_load_cv, sm->sm_lock);
}
}
/*
* Note: space_map_load() will drop sm_lock across dmu_read() calls.
* The caller must be OK with this.
*/
int
space_map_load(space_map_t *sm, space_map_ops_t *ops, uint8_t maptype,
space_map_obj_t *smo, objset_t *os)
{
uint64_t *entry, *entry_map, *entry_map_end;
uint64_t bufsize, size, offset, end, space;
uint64_t mapstart = sm->sm_start;
int error = 0;
ASSERT(MUTEX_HELD(sm->sm_lock));
ASSERT(!sm->sm_loaded);
ASSERT(!sm->sm_loading);
sm->sm_loading = B_TRUE;
end = smo->smo_objsize;
space = smo->smo_alloc;
ASSERT(sm->sm_ops == NULL);
VERIFY3U(sm->sm_space, ==, 0);
if (maptype == SM_FREE) {
space_map_add(sm, sm->sm_start, sm->sm_size);
space = sm->sm_size - space;
}
bufsize = 1ULL << SPACE_MAP_BLOCKSHIFT;
entry_map = zio_buf_alloc(bufsize);
mutex_exit(sm->sm_lock);
if (end > bufsize)
dmu_prefetch(os, smo->smo_object, bufsize, end - bufsize);
mutex_enter(sm->sm_lock);
for (offset = 0; offset < end; offset += bufsize) {
size = MIN(end - offset, bufsize);
VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0);
VERIFY(size != 0);
dprintf("object=%llu offset=%llx size=%llx\n",
smo->smo_object, offset, size);
mutex_exit(sm->sm_lock);
error = dmu_read(os, smo->smo_object, offset, size, entry_map,
DMU_READ_PREFETCH);
mutex_enter(sm->sm_lock);
if (error != 0)
break;
entry_map_end = entry_map + (size / sizeof (uint64_t));
for (entry = entry_map; entry < entry_map_end; entry++) {
uint64_t e = *entry;
if (SM_DEBUG_DECODE(e)) /* Skip debug entries */
continue;
(SM_TYPE_DECODE(e) == maptype ?
space_map_add : space_map_remove)(sm,
(SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart,
SM_RUN_DECODE(e) << sm->sm_shift);
}
}
if (error == 0) {
VERIFY3U(sm->sm_space, ==, space);
sm->sm_loaded = B_TRUE;
sm->sm_ops = ops;
if (ops != NULL)
ops->smop_load(sm);
} else {
space_map_vacate(sm, NULL, NULL);
}
zio_buf_free(entry_map, bufsize);
sm->sm_loading = B_FALSE;
cv_broadcast(&sm->sm_load_cv);
return (error);
}
void
space_map_unload(space_map_t *sm)
{
ASSERT(MUTEX_HELD(sm->sm_lock));
if (sm->sm_loaded && sm->sm_ops != NULL)
sm->sm_ops->smop_unload(sm);
sm->sm_loaded = B_FALSE;
sm->sm_ops = NULL;
space_map_vacate(sm, NULL, NULL);
}
uint64_t
space_map_maxsize(space_map_t *sm)
{
ASSERT(sm->sm_ops != NULL);
return (sm->sm_ops->smop_max(sm));
}
uint64_t
space_map_alloc(space_map_t *sm, uint64_t size)
{
uint64_t start;
start = sm->sm_ops->smop_alloc(sm, size);
if (start != -1ULL)
space_map_remove(sm, start, size);
return (start);
}
void
space_map_claim(space_map_t *sm, uint64_t start, uint64_t size)
{
sm->sm_ops->smop_claim(sm, start, size);
space_map_remove(sm, start, size);
}
void
space_map_free(space_map_t *sm, uint64_t start, uint64_t size)
{
space_map_add(sm, start, size);
sm->sm_ops->smop_free(sm, start, size);
}
/*
* Note: space_map_sync() will drop sm_lock across dmu_write() calls.
*/
void
space_map_sync(space_map_t *sm, uint8_t maptype,
space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)
{
spa_t *spa = dmu_objset_spa(os);
void *cookie = NULL;
space_seg_t *ss;
uint64_t bufsize, start, size, run_len;
uint64_t *entry, *entry_map, *entry_map_end;
ASSERT(MUTEX_HELD(sm->sm_lock));
if (sm->sm_space == 0)
return;
dprintf("object %4llu, txg %llu, pass %d, %c, count %lu, space %llx\n",
smo->smo_object, dmu_tx_get_txg(tx), spa_sync_pass(spa),
maptype == SM_ALLOC ? 'A' : 'F', avl_numnodes(&sm->sm_root),
sm->sm_space);
if (maptype == SM_ALLOC)
smo->smo_alloc += sm->sm_space;
else
smo->smo_alloc -= sm->sm_space;
bufsize = (8 + avl_numnodes(&sm->sm_root)) * sizeof (uint64_t);
bufsize = MIN(bufsize, 1ULL << SPACE_MAP_BLOCKSHIFT);
entry_map = zio_buf_alloc(bufsize);
entry_map_end = entry_map + (bufsize / sizeof (uint64_t));
entry = entry_map;
*entry++ = SM_DEBUG_ENCODE(1) |
SM_DEBUG_ACTION_ENCODE(maptype) |
SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |
SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));
while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
size = ss->ss_end - ss->ss_start;
start = (ss->ss_start - sm->sm_start) >> sm->sm_shift;
sm->sm_space -= size;
size >>= sm->sm_shift;
while (size) {
run_len = MIN(size, SM_RUN_MAX);
if (entry == entry_map_end) {
mutex_exit(sm->sm_lock);
dmu_write(os, smo->smo_object, smo->smo_objsize,
bufsize, entry_map, tx);
mutex_enter(sm->sm_lock);
smo->smo_objsize += bufsize;
entry = entry_map;
}
*entry++ = SM_OFFSET_ENCODE(start) |
SM_TYPE_ENCODE(maptype) |
SM_RUN_ENCODE(run_len);
start += run_len;
size -= run_len;
}
kmem_free(ss, sizeof (*ss));
}
if (entry != entry_map) {
size = (entry - entry_map) * sizeof (uint64_t);
mutex_exit(sm->sm_lock);
dmu_write(os, smo->smo_object, smo->smo_objsize,
size, entry_map, tx);
mutex_enter(sm->sm_lock);
smo->smo_objsize += size;
}
zio_buf_free(entry_map, bufsize);
VERIFY3U(sm->sm_space, ==, 0);
}
void
space_map_truncate(space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)
{
VERIFY(dmu_free_range(os, smo->smo_object, 0, -1ULL, tx) == 0);
smo->smo_objsize = 0;
smo->smo_alloc = 0;
}
/*
* Space map reference trees.
*
* A space map is a collection of integers. Every integer is either
* in the map, or it's not. A space map reference tree generalizes
* the idea: it allows its members to have arbitrary reference counts,
* as opposed to the implicit reference count of 0 or 1 in a space map.
* This representation comes in handy when computing the union or
* intersection of multiple space maps. For example, the union of
* N space maps is the subset of the reference tree with refcnt >= 1.
* The intersection of N space maps is the subset with refcnt >= N.
*
* [It's very much like a Fourier transform. Unions and intersections
* are hard to perform in the 'space map domain', so we convert the maps
* into the 'reference count domain', where it's trivial, then invert.]
*
* vdev_dtl_reassess() uses computations of this form to determine
* DTL_MISSING and DTL_OUTAGE for interior vdevs -- e.g. a RAID-Z vdev
* has an outage wherever refcnt >= vdev_nparity + 1, and a mirror vdev
* has an outage wherever refcnt >= vdev_children.
*/
static int
space_map_ref_compare(const void *x1, const void *x2)
{
const space_ref_t *sr1 = x1;
const space_ref_t *sr2 = x2;
if (sr1->sr_offset < sr2->sr_offset)
return (-1);
if (sr1->sr_offset > sr2->sr_offset)
return (1);
if (sr1 < sr2)
return (-1);
if (sr1 > sr2)
return (1);
return (0);
}
void
space_map_ref_create(avl_tree_t *t)
{
avl_create(t, space_map_ref_compare,
sizeof (space_ref_t), offsetof(space_ref_t, sr_node));
}
void
space_map_ref_destroy(avl_tree_t *t)
{
space_ref_t *sr;
void *cookie = NULL;
while ((sr = avl_destroy_nodes(t, &cookie)) != NULL)
kmem_free(sr, sizeof (*sr));
avl_destroy(t);
}
static void
space_map_ref_add_node(avl_tree_t *t, uint64_t offset, int64_t refcnt)
{
space_ref_t *sr;
sr = kmem_alloc(sizeof (*sr), KM_SLEEP);
sr->sr_offset = offset;
sr->sr_refcnt = refcnt;
avl_add(t, sr);
}
void
space_map_ref_add_seg(avl_tree_t *t, uint64_t start, uint64_t end,
int64_t refcnt)
{
space_map_ref_add_node(t, start, refcnt);
space_map_ref_add_node(t, end, -refcnt);
}
/*
* Convert (or add) a space map into a reference tree.
*/
void
space_map_ref_add_map(avl_tree_t *t, space_map_t *sm, int64_t refcnt)
{
space_seg_t *ss;
ASSERT(MUTEX_HELD(sm->sm_lock));
for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))
space_map_ref_add_seg(t, ss->ss_start, ss->ss_end, refcnt);
}
/*
* Convert a reference tree into a space map. The space map will contain
* all members of the reference tree for which refcnt >= minref.
*/
void
space_map_ref_generate_map(avl_tree_t *t, space_map_t *sm, int64_t minref)
{
uint64_t start = -1ULL;
int64_t refcnt = 0;
space_ref_t *sr;
ASSERT(MUTEX_HELD(sm->sm_lock));
space_map_vacate(sm, NULL, NULL);
for (sr = avl_first(t); sr != NULL; sr = AVL_NEXT(t, sr)) {
refcnt += sr->sr_refcnt;
if (refcnt >= minref) {
if (start == -1ULL) {
start = sr->sr_offset;
}
} else {
if (start != -1ULL) {
uint64_t end = sr->sr_offset;
ASSERT(start <= end);
if (end > start)
space_map_add(sm, start, end - start);
start = -1ULL;
}
}
}
ASSERT(refcnt == 0);
ASSERT(start == -1ULL);
}