mirror_zfs/module/os/freebsd/zfs/dmu_os.c
Andriy Gapon 2e160dee97
Fix assert in FreeBSD-specific dmu_read_pages
The function has three similar pieces of code: for read-behind pages,
requested pages and read-ahead pages.  All three pieces had an
assert to ensure that the page is not mapped.  Later the assert was
relaxed to require that the page is not mapped for writing.  But that
was done in two places out of three.  This change fixes the third piece,
read-ahead.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andriy Gapon <avg@FreeBSD.org>
Closes #11654
2021-02-27 17:23:09 -08:00

350 lines
8.9 KiB
C

/*
* Copyright (c) 2020 iXsystems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/param.h>
#include <sys/dmu.h>
#include <sys/dmu_impl.h>
#include <sys/dmu_tx.h>
#include <sys/dbuf.h>
#include <sys/dnode.h>
#include <sys/zfs_context.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_traverse.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_synctask.h>
#include <sys/dsl_prop.h>
#include <sys/dmu_zfetch.h>
#include <sys/zfs_ioctl.h>
#include <sys/zap.h>
#include <sys/zio_checksum.h>
#include <sys/zio_compress.h>
#include <sys/sa.h>
#include <sys/zfeature.h>
#include <sys/abd.h>
#include <sys/zfs_rlock.h>
#include <sys/racct.h>
#include <sys/vm.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_vnops.h>
#include <sys/ccompat.h>
#ifndef IDX_TO_OFF
#define IDX_TO_OFF(idx) (((vm_ooffset_t)(idx)) << PAGE_SHIFT)
#endif
#if __FreeBSD_version < 1300051
#define VM_ALLOC_BUSY_FLAGS VM_ALLOC_NOBUSY
#else
#define VM_ALLOC_BUSY_FLAGS VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY
#endif
#if __FreeBSD_version < 1300072
#define dmu_page_lock(m) vm_page_lock(m)
#define dmu_page_unlock(m) vm_page_unlock(m)
#else
#define dmu_page_lock(m)
#define dmu_page_unlock(m)
#endif
static int
dmu_buf_hold_array(objset_t *os, uint64_t object, uint64_t offset,
uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
{
dnode_t *dn;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
numbufsp, dbpp, DMU_READ_PREFETCH);
dnode_rele(dn, FTAG);
return (err);
}
int
dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
vm_page_t *ma, dmu_tx_t *tx)
{
dmu_buf_t **dbp;
struct sf_buf *sf;
int numbufs, i;
int err;
if (size == 0)
return (0);
err = dmu_buf_hold_array(os, object, offset, size,
FALSE, FTAG, &numbufs, &dbp);
if (err)
return (err);
for (i = 0; i < numbufs; i++) {
int tocpy, copied, thiscpy;
int bufoff;
dmu_buf_t *db = dbp[i];
caddr_t va;
ASSERT(size > 0);
ASSERT3U(db->db_size, >=, PAGESIZE);
bufoff = offset - db->db_offset;
tocpy = (int)MIN(db->db_size - bufoff, size);
ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
if (tocpy == db->db_size)
dmu_buf_will_fill(db, tx);
else
dmu_buf_will_dirty(db, tx);
for (copied = 0; copied < tocpy; copied += PAGESIZE) {
ASSERT3U(ptoa((*ma)->pindex), ==,
db->db_offset + bufoff);
thiscpy = MIN(PAGESIZE, tocpy - copied);
va = zfs_map_page(*ma, &sf);
bcopy(va, (char *)db->db_data + bufoff, thiscpy);
zfs_unmap_page(sf);
ma += 1;
bufoff += PAGESIZE;
}
if (tocpy == db->db_size)
dmu_buf_fill_done(db, tx);
offset += tocpy;
size -= tocpy;
}
dmu_buf_rele_array(dbp, numbufs, FTAG);
return (err);
}
int
dmu_read_pages(objset_t *os, uint64_t object, vm_page_t *ma, int count,
int *rbehind, int *rahead, int last_size)
{
struct sf_buf *sf;
vm_object_t vmobj;
vm_page_t m;
dmu_buf_t **dbp;
dmu_buf_t *db;
caddr_t va;
int numbufs, i;
int bufoff, pgoff, tocpy;
int mi, di;
int err;
ASSERT3U(ma[0]->pindex + count - 1, ==, ma[count - 1]->pindex);
ASSERT(last_size <= PAGE_SIZE);
err = dmu_buf_hold_array(os, object, IDX_TO_OFF(ma[0]->pindex),
IDX_TO_OFF(count - 1) + last_size, TRUE, FTAG, &numbufs, &dbp);
if (err != 0)
return (err);
#ifdef ZFS_DEBUG
IMPLY(last_size < PAGE_SIZE, *rahead == 0);
if (dbp[0]->db_offset != 0 || numbufs > 1) {
for (i = 0; i < numbufs; i++) {
ASSERT(ISP2(dbp[i]->db_size));
ASSERT((dbp[i]->db_offset % dbp[i]->db_size) == 0);
ASSERT3U(dbp[i]->db_size, ==, dbp[0]->db_size);
}
}
#endif
vmobj = ma[0]->object;
zfs_vmobject_wlock_12(vmobj);
db = dbp[0];
for (i = 0; i < *rbehind; i++) {
m = vm_page_grab_unlocked(vmobj, ma[0]->pindex - 1 - i,
VM_ALLOC_NORMAL | VM_ALLOC_NOWAIT | VM_ALLOC_BUSY_FLAGS);
if (m == NULL)
break;
if (!vm_page_none_valid(m)) {
ASSERT3U(m->valid, ==, VM_PAGE_BITS_ALL);
vm_page_do_sunbusy(m);
break;
}
ASSERT(m->dirty == 0);
ASSERT(!pmap_page_is_write_mapped(m));
ASSERT(db->db_size > PAGE_SIZE);
bufoff = IDX_TO_OFF(m->pindex) % db->db_size;
va = zfs_map_page(m, &sf);
bcopy((char *)db->db_data + bufoff, va, PAGESIZE);
zfs_unmap_page(sf);
vm_page_valid(m);
dmu_page_lock(m);
if ((m->busy_lock & VPB_BIT_WAITERS) != 0)
vm_page_activate(m);
else
vm_page_deactivate(m);
dmu_page_unlock(m);
vm_page_do_sunbusy(m);
}
*rbehind = i;
bufoff = IDX_TO_OFF(ma[0]->pindex) % db->db_size;
pgoff = 0;
for (mi = 0, di = 0; mi < count && di < numbufs; ) {
if (pgoff == 0) {
m = ma[mi];
if (m != bogus_page) {
vm_page_assert_xbusied(m);
ASSERT(vm_page_none_valid(m));
ASSERT(m->dirty == 0);
ASSERT(!pmap_page_is_write_mapped(m));
va = zfs_map_page(m, &sf);
}
}
if (bufoff == 0)
db = dbp[di];
if (m != bogus_page) {
ASSERT3U(IDX_TO_OFF(m->pindex) + pgoff, ==,
db->db_offset + bufoff);
}
/*
* We do not need to clamp the copy size by the file
* size as the last block is zero-filled beyond the
* end of file anyway.
*/
tocpy = MIN(db->db_size - bufoff, PAGESIZE - pgoff);
if (m != bogus_page)
bcopy((char *)db->db_data + bufoff, va + pgoff, tocpy);
pgoff += tocpy;
ASSERT(pgoff <= PAGESIZE);
if (pgoff == PAGESIZE) {
if (m != bogus_page) {
zfs_unmap_page(sf);
vm_page_valid(m);
}
ASSERT(mi < count);
mi++;
pgoff = 0;
}
bufoff += tocpy;
ASSERT(bufoff <= db->db_size);
if (bufoff == db->db_size) {
ASSERT(di < numbufs);
di++;
bufoff = 0;
}
}
#ifdef ZFS_DEBUG
/*
* Three possibilities:
* - last requested page ends at a buffer boundary and , thus,
* all pages and buffers have been iterated;
* - all requested pages are filled, but the last buffer
* has not been exhausted;
* the read-ahead is possible only in this case;
* - all buffers have been read, but the last page has not been
* fully filled;
* this is only possible if the file has only a single buffer
* with a size that is not a multiple of the page size.
*/
if (mi == count) {
ASSERT(di >= numbufs - 1);
IMPLY(*rahead != 0, di == numbufs - 1);
IMPLY(*rahead != 0, bufoff != 0);
ASSERT(pgoff == 0);
}
if (di == numbufs) {
ASSERT(mi >= count - 1);
ASSERT(*rahead == 0);
IMPLY(pgoff == 0, mi == count);
if (pgoff != 0) {
ASSERT(mi == count - 1);
ASSERT((dbp[0]->db_size & PAGE_MASK) != 0);
}
}
#endif
if (pgoff != 0) {
ASSERT(m != bogus_page);
bzero(va + pgoff, PAGESIZE - pgoff);
zfs_unmap_page(sf);
vm_page_valid(m);
}
for (i = 0; i < *rahead; i++) {
m = vm_page_grab_unlocked(vmobj, ma[count - 1]->pindex + 1 + i,
VM_ALLOC_NORMAL | VM_ALLOC_NOWAIT | VM_ALLOC_BUSY_FLAGS);
if (m == NULL)
break;
if (!vm_page_none_valid(m)) {
ASSERT3U(m->valid, ==, VM_PAGE_BITS_ALL);
vm_page_do_sunbusy(m);
break;
}
ASSERT(m->dirty == 0);
ASSERT(!pmap_page_is_write_mapped(m));
ASSERT(db->db_size > PAGE_SIZE);
bufoff = IDX_TO_OFF(m->pindex) % db->db_size;
tocpy = MIN(db->db_size - bufoff, PAGESIZE);
va = zfs_map_page(m, &sf);
bcopy((char *)db->db_data + bufoff, va, tocpy);
if (tocpy < PAGESIZE) {
ASSERT(i == *rahead - 1);
ASSERT((db->db_size & PAGE_MASK) != 0);
bzero(va + tocpy, PAGESIZE - tocpy);
}
zfs_unmap_page(sf);
vm_page_valid(m);
dmu_page_lock(m);
if ((m->busy_lock & VPB_BIT_WAITERS) != 0)
vm_page_activate(m);
else
vm_page_deactivate(m);
dmu_page_unlock(m);
vm_page_do_sunbusy(m);
}
*rahead = i;
zfs_vmobject_wunlock_12(vmobj);
dmu_buf_rele_array(dbp, numbufs, FTAG);
return (0);
}