freebsd-nq/sys/boot/common/disk.c
Allan Jude 87ed2b7f5a A new implementation of the loader block cache
The block cache implementation in loader has proven to be almost useless, and in worst case even slowing down the disk reads due to insufficient cache size and extra memory copy.
Also the current cache implementation does not cache reads from CDs, or work with zfs built on top of multiple disks.
Instead of an LRU, this code uses a simple hash (O(1) read from cache), and instead of a single global cache, a separate cache per block device.
The cache also implements limited read-ahead to increase performance.
To simplify read ahead management, the read ahead will not wrap over bcache end, so in worst case, single block physical read will be performed to fill the last block in bcache.

Booting from a virtual CD over IPMI:
0ms latency, before: 27 second, after: 7 seconds
60ms latency, before: over 12 minutes, after: under 5 minutes.

Submitted by:	Toomas Soome <tsoome@me.com>
Reviewed by:	delphij (previous version), emaste (previous version)
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D4713
2016-04-18 23:09:22 +00:00

530 lines
13 KiB
C

/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* Copyright (c) 2012 Andrey V. Elsukov <ae@FreeBSD.org>
* 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 AUTHOR 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 AUTHOR 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/disk.h>
#include <sys/queue.h>
#include <stand.h>
#include <stdarg.h>
#include <bootstrap.h>
#include <part.h>
#include "disk.h"
#ifdef DISK_DEBUG
# define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args)
#else
# define DEBUG(fmt, args...)
#endif
struct open_disk {
struct ptable *table;
off_t mediasize;
u_int sectorsize;
u_int flags;
int rcnt;
};
struct print_args {
struct disk_devdesc *dev;
const char *prefix;
int verbose;
};
struct dentry {
const struct devsw *d_dev;
int d_unit;
int d_slice;
int d_partition;
struct open_disk *od;
off_t d_offset;
STAILQ_ENTRY(dentry) entry;
#ifdef DISK_DEBUG
uint32_t count;
#endif
};
static STAILQ_HEAD(, dentry) opened_disks =
STAILQ_HEAD_INITIALIZER(opened_disks);
static int
disk_lookup(struct disk_devdesc *dev)
{
struct dentry *entry;
int rc;
rc = ENOENT;
STAILQ_FOREACH(entry, &opened_disks, entry) {
if (entry->d_dev != dev->d_dev ||
entry->d_unit != dev->d_unit)
continue;
dev->d_opendata = entry->od;
if (entry->d_slice == dev->d_slice &&
entry->d_partition == dev->d_partition) {
dev->d_offset = entry->d_offset;
DEBUG("%s offset %lld", disk_fmtdev(dev),
(long long)dev->d_offset);
#ifdef DISK_DEBUG
entry->count++;
#endif
return (0);
}
rc = EAGAIN;
}
return (rc);
}
static void
disk_insert(struct disk_devdesc *dev)
{
struct dentry *entry;
entry = (struct dentry *)malloc(sizeof(struct dentry));
if (entry == NULL) {
DEBUG("no memory");
return;
}
entry->d_dev = dev->d_dev;
entry->d_unit = dev->d_unit;
entry->d_slice = dev->d_slice;
entry->d_partition = dev->d_partition;
entry->od = (struct open_disk *)dev->d_opendata;
entry->od->rcnt++;
entry->d_offset = dev->d_offset;
#ifdef DISK_DEBUG
entry->count = 1;
#endif
STAILQ_INSERT_TAIL(&opened_disks, entry, entry);
DEBUG("%s cached", disk_fmtdev(dev));
}
#ifdef DISK_DEBUG
COMMAND_SET(dcachestat, "dcachestat", "get disk cache stats",
command_dcachestat);
static int
command_dcachestat(int argc, char *argv[])
{
struct disk_devdesc dev;
struct dentry *entry;
STAILQ_FOREACH(entry, &opened_disks, entry) {
dev.d_dev = (struct devsw *)entry->d_dev;
dev.d_unit = entry->d_unit;
dev.d_slice = entry->d_slice;
dev.d_partition = entry->d_partition;
printf("%s %d => %p [%d]\n", disk_fmtdev(&dev), entry->count,
entry->od, entry->od->rcnt);
}
return (CMD_OK);
}
#endif /* DISK_DEBUG */
/* Convert size to a human-readable number. */
static char *
display_size(uint64_t size, u_int sectorsize)
{
static char buf[80];
char unit;
size = size * sectorsize / 1024;
unit = 'K';
if (size >= 10485760000LL) {
size /= 1073741824;
unit = 'T';
} else if (size >= 10240000) {
size /= 1048576;
unit = 'G';
} else if (size >= 10000) {
size /= 1024;
unit = 'M';
}
sprintf(buf, "%ld%cB", (long)size, unit);
return (buf);
}
int
ptblread(void *d, void *buf, size_t blocks, off_t offset)
{
struct disk_devdesc *dev;
struct open_disk *od;
dev = (struct disk_devdesc *)d;
od = (struct open_disk *)dev->d_opendata;
return (dev->d_dev->dv_strategy(dev, F_READ, offset, 0,
blocks * od->sectorsize, (char *)buf, NULL));
}
#define PWIDTH 35
static void
ptable_print(void *arg, const char *pname, const struct ptable_entry *part)
{
struct print_args *pa, bsd;
struct open_disk *od;
struct ptable *table;
char line[80];
pa = (struct print_args *)arg;
od = (struct open_disk *)pa->dev->d_opendata;
sprintf(line, " %s%s: %s", pa->prefix, pname,
parttype2str(part->type));
if (pa->verbose)
sprintf(line, "%-*s%s", PWIDTH, line,
display_size(part->end - part->start + 1,
od->sectorsize));
strcat(line, "\n");
pager_output(line);
if (part->type == PART_FREEBSD) {
/* Open slice with BSD label */
pa->dev->d_offset = part->start;
table = ptable_open(pa->dev, part->end - part->start + 1,
od->sectorsize, ptblread);
if (table == NULL)
return;
sprintf(line, " %s%s", pa->prefix, pname);
bsd.dev = pa->dev;
bsd.prefix = line;
bsd.verbose = pa->verbose;
ptable_iterate(table, &bsd, ptable_print);
ptable_close(table);
}
}
#undef PWIDTH
void
disk_print(struct disk_devdesc *dev, char *prefix, int verbose)
{
struct open_disk *od;
struct print_args pa;
/* Disk should be opened */
od = (struct open_disk *)dev->d_opendata;
pa.dev = dev;
pa.prefix = prefix;
pa.verbose = verbose;
ptable_iterate(od->table, &pa, ptable_print);
}
int
disk_read(struct disk_devdesc *dev, void *buf, off_t offset, u_int blocks)
{
struct open_disk *od;
int ret;
od = (struct open_disk *)dev->d_opendata;
ret = dev->d_dev->dv_strategy(dev, F_READ, dev->d_offset + offset, 0,
blocks * od->sectorsize, buf, NULL);
return (ret);
}
int
disk_write(struct disk_devdesc *dev, void *buf, off_t offset, u_int blocks)
{
struct open_disk *od;
int ret;
od = (struct open_disk *)dev->d_opendata;
ret = dev->d_dev->dv_strategy(dev, F_WRITE, dev->d_offset + offset, 0,
blocks * od->sectorsize, buf, NULL);
return (ret);
}
int
disk_ioctl(struct disk_devdesc *dev, u_long cmd, void *buf)
{
if (dev->d_dev->dv_ioctl)
return ((*dev->d_dev->dv_ioctl)(dev->d_opendata, cmd, buf));
return (ENXIO);
}
int
disk_open(struct disk_devdesc *dev, off_t mediasize, u_int sectorsize,
u_int flags)
{
struct open_disk *od;
struct ptable *table;
struct ptable_entry part;
int rc, slice, partition;
rc = 0;
if ((flags & DISK_F_NOCACHE) == 0) {
rc = disk_lookup(dev);
if (rc == 0)
return (0);
}
/*
* While we are reading disk metadata, make sure we do it relative
* to the start of the disk
*/
dev->d_offset = 0;
table = NULL;
slice = dev->d_slice;
partition = dev->d_partition;
if (rc == EAGAIN) {
/*
* This entire disk was already opened and there is no
* need to allocate new open_disk structure and open the
* main partition table.
*/
od = (struct open_disk *)dev->d_opendata;
DEBUG("%s unit %d, slice %d, partition %d => %p (cached)",
disk_fmtdev(dev), dev->d_unit, dev->d_slice,
dev->d_partition, od);
goto opened;
} else {
od = (struct open_disk *)malloc(sizeof(struct open_disk));
if (od == NULL) {
DEBUG("no memory");
return (ENOMEM);
}
dev->d_opendata = od;
od->rcnt = 0;
}
od->mediasize = mediasize;
od->sectorsize = sectorsize;
od->flags = flags;
DEBUG("%s unit %d, slice %d, partition %d => %p",
disk_fmtdev(dev), dev->d_unit, dev->d_slice, dev->d_partition, od);
/* Determine disk layout. */
od->table = ptable_open(dev, mediasize / sectorsize, sectorsize,
ptblread);
if (od->table == NULL) {
DEBUG("Can't read partition table");
rc = ENXIO;
goto out;
}
opened:
rc = 0;
if (ptable_gettype(od->table) == PTABLE_BSD &&
partition >= 0) {
/* It doesn't matter what value has d_slice */
rc = ptable_getpart(od->table, &part, partition);
if (rc == 0)
dev->d_offset = part.start;
} else if (slice >= 0) {
/* Try to get information about partition */
if (slice == 0)
rc = ptable_getbestpart(od->table, &part);
else
rc = ptable_getpart(od->table, &part, slice);
if (rc != 0) /* Partition doesn't exist */
goto out;
dev->d_offset = part.start;
slice = part.index;
if (ptable_gettype(od->table) == PTABLE_GPT) {
partition = 255;
goto out; /* Nothing more to do */
} else if (partition == 255) {
/*
* When we try to open GPT partition, but partition
* table isn't GPT, reset d_partition value to -1
* and try to autodetect appropriate value.
*/
partition = -1;
}
/*
* If d_partition < 0 and we are looking at a BSD slice,
* then try to read BSD label, otherwise return the
* whole MBR slice.
*/
if (partition == -1 &&
part.type != PART_FREEBSD)
goto out;
/* Try to read BSD label */
table = ptable_open(dev, part.end - part.start + 1,
od->sectorsize, ptblread);
if (table == NULL) {
DEBUG("Can't read BSD label");
rc = ENXIO;
goto out;
}
/*
* If slice contains BSD label and d_partition < 0, then
* assume the 'a' partition. Otherwise just return the
* whole MBR slice, because it can contain ZFS.
*/
if (partition < 0) {
if (ptable_gettype(table) != PTABLE_BSD)
goto out;
partition = 0;
}
rc = ptable_getpart(table, &part, partition);
if (rc != 0)
goto out;
dev->d_offset += part.start;
}
out:
if (table != NULL)
ptable_close(table);
if (rc != 0) {
if (od->rcnt < 1) {
if (od->table != NULL)
ptable_close(od->table);
free(od);
}
DEBUG("%s could not open", disk_fmtdev(dev));
} else {
if ((flags & DISK_F_NOCACHE) == 0)
disk_insert(dev);
/* Save the slice and partition number to the dev */
dev->d_slice = slice;
dev->d_partition = partition;
DEBUG("%s offset %lld => %p", disk_fmtdev(dev),
(long long)dev->d_offset, od);
}
return (rc);
}
int
disk_close(struct disk_devdesc *dev)
{
struct open_disk *od;
od = (struct open_disk *)dev->d_opendata;
DEBUG("%s closed => %p [%d]", disk_fmtdev(dev), od, od->rcnt);
if (od->flags & DISK_F_NOCACHE) {
ptable_close(od->table);
free(od);
}
return (0);
}
void
disk_cleanup(const struct devsw *d_dev)
{
#ifdef DISK_DEBUG
struct disk_devdesc dev;
#endif
struct dentry *entry, *tmp;
STAILQ_FOREACH_SAFE(entry, &opened_disks, entry, tmp) {
if (entry->d_dev != d_dev)
continue;
entry->od->rcnt--;
#ifdef DISK_DEBUG
dev.d_dev = (struct devsw *)entry->d_dev;
dev.d_unit = entry->d_unit;
dev.d_slice = entry->d_slice;
dev.d_partition = entry->d_partition;
DEBUG("%s was freed => %p [%d]", disk_fmtdev(&dev),
entry->od, entry->od->rcnt);
#endif
STAILQ_REMOVE(&opened_disks, entry, dentry, entry);
if (entry->od->rcnt < 1) {
if (entry->od->table != NULL)
ptable_close(entry->od->table);
free(entry->od);
}
free(entry);
}
}
char*
disk_fmtdev(struct disk_devdesc *dev)
{
static char buf[128];
char *cp;
cp = buf + sprintf(buf, "%s%d", dev->d_dev->dv_name, dev->d_unit);
if (dev->d_slice >= 0) {
#ifdef LOADER_GPT_SUPPORT
if (dev->d_partition == 255) {
sprintf(cp, "p%d:", dev->d_slice);
return (buf);
} else
#endif
#ifdef LOADER_MBR_SUPPORT
cp += sprintf(cp, "s%d", dev->d_slice);
#endif
}
if (dev->d_partition >= 0)
cp += sprintf(cp, "%c", dev->d_partition + 'a');
strcat(cp, ":");
return (buf);
}
int
disk_parsedev(struct disk_devdesc *dev, const char *devspec, const char **path)
{
int unit, slice, partition;
const char *np;
char *cp;
np = devspec;
unit = slice = partition = -1;
if (*np != '\0' && *np != ':') {
unit = strtol(np, &cp, 10);
if (cp == np)
return (EUNIT);
#ifdef LOADER_GPT_SUPPORT
if (*cp == 'p') {
np = cp + 1;
slice = strtol(np, &cp, 10);
if (np == cp)
return (ESLICE);
/* we don't support nested partitions on GPT */
if (*cp != '\0' && *cp != ':')
return (EINVAL);
partition = 255;
} else
#endif
#ifdef LOADER_MBR_SUPPORT
if (*cp == 's') {
np = cp + 1;
slice = strtol(np, &cp, 10);
if (np == cp)
return (ESLICE);
}
#endif
if (*cp != '\0' && *cp != ':') {
partition = *cp - 'a';
if (partition < 0)
return (EPART);
cp++;
}
} else
return (EINVAL);
if (*cp != '\0' && *cp != ':')
return (EINVAL);
dev->d_unit = unit;
dev->d_slice = slice;
dev->d_partition = partition;
if (path != NULL)
*path = (*cp == '\0') ? cp: cp + 1;
return (0);
}