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|
/*
* 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 (c) 2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*/
/*
* Copyright 2007 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* ZFS volume emulation driver.
*
* Makes a DMU object look like a volume of arbitrary size, up to 2^64 bytes.
* Volumes are accessed through the symbolic links named:
*
* /dev/zvol/dsk/<pool_name>/<dataset_name>
* /dev/zvol/rdsk/<pool_name>/<dataset_name>
*
* These links are created by the ZFS-specific devfsadm link generator.
* Volumes are persistent through reboot. No user command needs to be
* run before opening and using a device.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/uio.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/kmem.h>
#include <sys/conf.h>
#include <sys/cmn_err.h>
#include <sys/stat.h>
#include <sys/zap.h>
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/dsl_prop.h>
#include <sys/dkio.h>
#include <sys/byteorder.h>
#include <sys/sunddi.h>
#include <sys/dirent.h>
#include <sys/policy.h>
#include <sys/fs/zfs.h>
#include <sys/zfs_ioctl.h>
#include <sys/zil.h>
#include <sys/refcount.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_rlock.h>
#include <geom/geom.h>
#include "zfs_namecheck.h"
struct g_class zfs_zvol_class = {
.name = "ZFS::ZVOL",
.version = G_VERSION,
};
DECLARE_GEOM_CLASS(zfs_zvol_class, zfs_zvol);
#define ZVOL_OBJ 1ULL
#define ZVOL_ZAP_OBJ 2ULL
static uint32_t zvol_minors;
/*
* The in-core state of each volume.
*/
typedef struct zvol_state {
char zv_name[MAXPATHLEN]; /* pool/dd name */
uint64_t zv_volsize; /* amount of space we advertise */
uint64_t zv_volblocksize; /* volume block size */
struct g_provider *zv_provider; /* GEOM provider */
uint8_t zv_min_bs; /* minimum addressable block shift */
uint8_t zv_readonly; /* hard readonly; like write-protect */
objset_t *zv_objset; /* objset handle */
uint32_t zv_mode; /* DS_MODE_* flags at open time */
uint32_t zv_total_opens; /* total open count */
zilog_t *zv_zilog; /* ZIL handle */
uint64_t zv_txg_assign; /* txg to assign during ZIL replay */
znode_t zv_znode; /* for range locking */
int zv_state;
struct bio_queue_head zv_queue;
struct mtx zv_queue_mtx; /* zv_queue mutex */
} zvol_state_t;
/*
* zvol maximum transfer in one DMU tx.
*/
int zvol_maxphys = DMU_MAX_ACCESS/2;
static int zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio);
int
zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
{
if (volsize == 0)
return (EINVAL);
if (volsize % blocksize != 0)
return (EINVAL);
#ifdef _ILP32
if (volsize - 1 > SPEC_MAXOFFSET_T)
return (EOVERFLOW);
#endif
return (0);
}
int
zvol_check_volblocksize(uint64_t volblocksize)
{
if (volblocksize < SPA_MINBLOCKSIZE ||
volblocksize > SPA_MAXBLOCKSIZE ||
!ISP2(volblocksize))
return (EDOM);
return (0);
}
static void
zvol_readonly_changed_cb(void *arg, uint64_t newval)
{
zvol_state_t *zv = arg;
zv->zv_readonly = (uint8_t)newval;
}
int
zvol_get_stats(objset_t *os, nvlist_t *nv)
{
int error;
dmu_object_info_t doi;
uint64_t val;
error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &val);
if (error)
return (error);
dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val);
error = dmu_object_info(os, ZVOL_OBJ, &doi);
if (error == 0) {
dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLBLOCKSIZE,
doi.doi_data_block_size);
}
return (error);
}
static zvol_state_t *
zvol_minor_lookup(const char *name)
{
struct g_provider *pp;
struct g_geom *gp;
g_topology_assert();
LIST_FOREACH(gp, &zfs_zvol_class.geom, geom) {
LIST_FOREACH(pp, &gp->provider, provider) {
if (strcmp(pp->name + sizeof(ZVOL_DEV_DIR), name) == 0)
return (pp->private);
}
}
return (NULL);
}
static int
zvol_access(struct g_provider *pp, int acr, int acw, int ace)
{
zvol_state_t *zv;
g_topology_assert();
zv = pp->private;
if (zv == NULL) {
if (acr <= 0 && acw <= 0 && ace <= 0)
return (0);
return (pp->error);
}
ASSERT(zv->zv_objset != NULL);
if (acw > 0 && (zv->zv_readonly || (zv->zv_mode & DS_MODE_READONLY)))
return (EROFS);
zv->zv_total_opens += acr + acw + ace;
return (0);
}
/*
* zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
*
* We store data in the log buffers if it's small enough.
* Otherwise we will later flush the data out via dmu_sync().
*/
ssize_t zvol_immediate_write_sz = 32768;
static void
zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, offset_t off, ssize_t len)
{
uint32_t blocksize = zv->zv_volblocksize;
lr_write_t *lr;
while (len) {
ssize_t nbytes = MIN(len, blocksize - P2PHASE(off, blocksize));
itx_t *itx = zil_itx_create(TX_WRITE, sizeof (*lr));
itx->itx_wr_state =
len > zvol_immediate_write_sz ? WR_INDIRECT : WR_NEED_COPY;
itx->itx_private = zv;
lr = (lr_write_t *)&itx->itx_lr;
lr->lr_foid = ZVOL_OBJ;
lr->lr_offset = off;
lr->lr_length = nbytes;
lr->lr_blkoff = off - P2ALIGN_TYPED(off, blocksize, uint64_t);
BP_ZERO(&lr->lr_blkptr);
(void) zil_itx_assign(zv->zv_zilog, itx, tx);
len -= nbytes;
off += nbytes;
}
}
static void
zvol_start(struct bio *bp)
{
zvol_state_t *zv;
switch (bp->bio_cmd) {
case BIO_READ:
case BIO_WRITE:
case BIO_FLUSH:
zv = bp->bio_to->private;
ASSERT(zv != NULL);
mtx_lock(&zv->zv_queue_mtx);
bioq_insert_tail(&zv->zv_queue, bp);
wakeup_one(&zv->zv_queue);
mtx_unlock(&zv->zv_queue_mtx);
break;
case BIO_DELETE:
case BIO_GETATTR:
default:
g_io_deliver(bp, EOPNOTSUPP);
break;
}
}
static void
zvol_serve_one(zvol_state_t *zv, struct bio *bp)
{
uint64_t off, volsize;
size_t size, resid;
char *addr;
objset_t *os;
rl_t *rl;
int error = 0;
boolean_t reading;
off = bp->bio_offset;
volsize = zv->zv_volsize;
os = zv->zv_objset;
ASSERT(os != NULL);
addr = bp->bio_data;
resid = bp->bio_length;
error = 0;
/*
* There must be no buffer changes when doing a dmu_sync() because
* we can't change the data whilst calculating the checksum.
* A better approach than a per zvol rwlock would be to lock ranges.
*/
reading = (bp->bio_cmd == BIO_READ);
rl = zfs_range_lock(&zv->zv_znode, off, resid,
reading ? RL_READER : RL_WRITER);
while (resid != 0 && off < volsize) {
size = MIN(resid, zvol_maxphys); /* zvol_maxphys per tx */
if (size > volsize - off) /* don't write past the end */
size = volsize - off;
if (reading) {
error = dmu_read(os, ZVOL_OBJ, off, size, addr);
} else {
dmu_tx_t *tx = dmu_tx_create(os);
dmu_tx_hold_write(tx, ZVOL_OBJ, off, size);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
} else {
dmu_write(os, ZVOL_OBJ, off, size, addr, tx);
zvol_log_write(zv, tx, off, size);
dmu_tx_commit(tx);
}
}
if (error)
break;
off += size;
addr += size;
resid -= size;
}
zfs_range_unlock(rl);
bp->bio_completed = bp->bio_length - resid;
if (bp->bio_completed < bp->bio_length)
bp->bio_error = (off > volsize ? EINVAL : error);
}
static void
zvol_worker(void *arg)
{
zvol_state_t *zv;
struct bio *bp;
zv = arg;
for (;;) {
mtx_lock(&zv->zv_queue_mtx);
bp = bioq_takefirst(&zv->zv_queue);
if (bp == NULL) {
if (zv->zv_state == 1) {
zv->zv_state = 2;
wakeup(&zv->zv_state);
mtx_unlock(&zv->zv_queue_mtx);
kproc_exit(0);
}
msleep(&zv->zv_queue, &zv->zv_queue_mtx, PRIBIO | PDROP,
"zvol:io", 0);
continue;
}
mtx_unlock(&zv->zv_queue_mtx);
switch (bp->bio_cmd) {
case BIO_FLUSH:
break;
case BIO_READ:
case BIO_WRITE:
zvol_serve_one(zv, bp);
break;
}
if (bp->bio_cmd != BIO_READ && !zil_disable)
zil_commit(zv->zv_zilog, UINT64_MAX, ZVOL_OBJ);
g_io_deliver(bp, bp->bio_error);
}
}
void
zvol_create_cb(objset_t *os, void *arg, dmu_tx_t *tx)
{
zfs_create_data_t *zc = arg;
int error;
uint64_t volblocksize, volsize;
VERIFY(nvlist_lookup_uint64(zc->zc_props,
zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0);
if (nvlist_lookup_uint64(zc->zc_props,
zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0)
volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE);
/*
* These properites must be removed from the list so the generic
* property setting step won't apply to them.
*/
VERIFY(nvlist_remove_all(zc->zc_props,
zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0);
(void) nvlist_remove_all(zc->zc_props,
zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE));
error = dmu_object_claim(os, ZVOL_OBJ, DMU_OT_ZVOL, volblocksize,
DMU_OT_NONE, 0, tx);
ASSERT(error == 0);
error = zap_create_claim(os, ZVOL_ZAP_OBJ, DMU_OT_ZVOL_PROP,
DMU_OT_NONE, 0, tx);
ASSERT(error == 0);
error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx);
ASSERT(error == 0);
}
/*
* Replay a TX_WRITE ZIL transaction that didn't get committed
* after a system failure
*/
static int
zvol_replay_write(zvol_state_t *zv, lr_write_t *lr, boolean_t byteswap)
{
objset_t *os = zv->zv_objset;
char *data = (char *)(lr + 1); /* data follows lr_write_t */
uint64_t off = lr->lr_offset;
uint64_t len = lr->lr_length;
dmu_tx_t *tx;
int error;
if (byteswap)
byteswap_uint64_array(lr, sizeof (*lr));
tx = dmu_tx_create(os);
dmu_tx_hold_write(tx, ZVOL_OBJ, off, len);
error = dmu_tx_assign(tx, zv->zv_txg_assign);
if (error) {
dmu_tx_abort(tx);
} else {
dmu_write(os, ZVOL_OBJ, off, len, data, tx);
dmu_tx_commit(tx);
}
return (error);
}
/* ARGSUSED */
static int
zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap)
{
return (ENOTSUP);
}
/*
* Callback vectors for replaying records.
* Only TX_WRITE is needed for zvol.
*/
zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = {
zvol_replay_err, /* 0 no such transaction type */
zvol_replay_err, /* TX_CREATE */
zvol_replay_err, /* TX_MKDIR */
zvol_replay_err, /* TX_MKXATTR */
zvol_replay_err, /* TX_SYMLINK */
zvol_replay_err, /* TX_REMOVE */
zvol_replay_err, /* TX_RMDIR */
zvol_replay_err, /* TX_LINK */
zvol_replay_err, /* TX_RENAME */
zvol_replay_write, /* TX_WRITE */
zvol_replay_err, /* TX_TRUNCATE */
zvol_replay_err, /* TX_SETATTR */
zvol_replay_err, /* TX_ACL */
};
/*
* Create a minor node for the specified volume.
*/
int
zvol_create_minor(const char *name, dev_t dev)
{
struct g_provider *pp;
struct g_geom *gp;
zvol_state_t *zv;
objset_t *os;
dmu_object_info_t doi;
uint64_t volsize;
int ds_mode = DS_MODE_PRIMARY;
int error;
DROP_GIANT();
g_topology_lock();
if ((zv = zvol_minor_lookup(name)) != NULL) {
error = EEXIST;
goto end;
}
if (strchr(name, '@') != 0)
ds_mode |= DS_MODE_READONLY;
error = dmu_objset_open(name, DMU_OST_ZVOL, ds_mode, &os);
if (error)
goto end;
g_topology_unlock();
PICKUP_GIANT();
error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
DROP_GIANT();
g_topology_lock();
if (error) {
dmu_objset_close(os);
goto end;
}
gp = g_new_geomf(&zfs_zvol_class, "zfs::zvol::%s", name);
gp->start = zvol_start;
gp->access = zvol_access;
pp = g_new_providerf(gp, "%s/%s", ZVOL_DEV_DIR, name);
pp->mediasize = volsize;
pp->sectorsize = DEV_BSIZE;
zv = kmem_zalloc(sizeof(*zv), KM_SLEEP);
(void) strcpy(zv->zv_name, name);
zv->zv_min_bs = DEV_BSHIFT;
zv->zv_provider = pp;
zv->zv_volsize = pp->mediasize;
zv->zv_objset = os;
zv->zv_mode = ds_mode;
zv->zv_zilog = zil_open(os, zvol_get_data);
mutex_init(&zv->zv_znode.z_range_lock, NULL, MUTEX_DEFAULT, NULL);
avl_create(&zv->zv_znode.z_range_avl, zfs_range_compare,
sizeof (rl_t), offsetof(rl_t, r_node));
/* get and cache the blocksize */
error = dmu_object_info(os, ZVOL_OBJ, &doi);
ASSERT(error == 0);
zv->zv_volblocksize = doi.doi_data_block_size;
zil_replay(os, zv, &zv->zv_txg_assign, zvol_replay_vector);
/* XXX this should handle the possible i/o error */
VERIFY(dsl_prop_register(dmu_objset_ds(zv->zv_objset),
"readonly", zvol_readonly_changed_cb, zv) == 0);
pp->private = zv;
g_error_provider(pp, 0);
bioq_init(&zv->zv_queue);
mtx_init(&zv->zv_queue_mtx, "zvol", NULL, MTX_DEF);
zv->zv_state = 0;
kproc_create(zvol_worker, zv, NULL, 0, 0, "zvol:worker %s", pp->name);
zvol_minors++;
end:
g_topology_unlock();
PICKUP_GIANT();
return (error);
}
/*
* Remove minor node for the specified volume.
*/
int
zvol_remove_minor(const char *name)
{
struct g_provider *pp;
zvol_state_t *zv;
int error = 0;
DROP_GIANT();
g_topology_lock();
if ((zv = zvol_minor_lookup(name)) == NULL) {
error = ENXIO;
goto end;
}
if (zv->zv_total_opens != 0) {
error = EBUSY;
goto end;
}
VERIFY(dsl_prop_unregister(dmu_objset_ds(zv->zv_objset),
"readonly", zvol_readonly_changed_cb, zv) == 0);
mtx_lock(&zv->zv_queue_mtx);
zv->zv_state = 1;
wakeup_one(&zv->zv_queue);
while (zv->zv_state != 2)
msleep(&zv->zv_state, &zv->zv_queue_mtx, 0, "zvol:w", 0);
mtx_unlock(&zv->zv_queue_mtx);
mtx_destroy(&zv->zv_queue_mtx);
pp = zv->zv_provider;
pp->private = NULL;
g_wither_geom(pp->geom, ENXIO);
zil_close(zv->zv_zilog);
zv->zv_zilog = NULL;
dmu_objset_close(zv->zv_objset);
zv->zv_objset = NULL;
avl_destroy(&zv->zv_znode.z_range_avl);
mutex_destroy(&zv->zv_znode.z_range_lock);
kmem_free(zv, sizeof(*zv));
zvol_minors--;
end:
g_topology_unlock();
PICKUP_GIANT();
return (error);
}
int
zvol_set_volsize(const char *name, dev_t dev, uint64_t volsize)
{
zvol_state_t *zv;
dmu_tx_t *tx;
int error;
dmu_object_info_t doi;
DROP_GIANT();
g_topology_lock();
if ((zv = zvol_minor_lookup(name)) == NULL) {
error = ENXIO;
goto end;
}
if ((error = dmu_object_info(zv->zv_objset, ZVOL_OBJ, &doi)) != 0 ||
(error = zvol_check_volsize(volsize,
doi.doi_data_block_size)) != 0) {
goto end;
}
if (zv->zv_readonly || (zv->zv_mode & DS_MODE_READONLY)) {
error = EROFS;
goto end;
}
tx = dmu_tx_create(zv->zv_objset);
dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
dmu_tx_hold_free(tx, ZVOL_OBJ, volsize, DMU_OBJECT_END);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
goto end;
}
error = zap_update(zv->zv_objset, ZVOL_ZAP_OBJ, "size", 8, 1,
&volsize, tx);
if (error == 0) {
error = dmu_free_range(zv->zv_objset, ZVOL_OBJ, volsize,
DMU_OBJECT_END, tx);
}
dmu_tx_commit(tx);
if (error == 0) {
zv->zv_volsize = volsize;
zv->zv_provider->mediasize = volsize; /* XXX: Not supported. */
}
end:
g_topology_unlock();
PICKUP_GIANT();
return (error);
}
int
zvol_set_volblocksize(const char *name, uint64_t volblocksize)
{
zvol_state_t *zv;
dmu_tx_t *tx;
int error;
DROP_GIANT();
g_topology_lock();
if ((zv = zvol_minor_lookup(name)) == NULL) {
error = ENXIO;
goto end;
}
if (zv->zv_readonly || (zv->zv_mode & DS_MODE_READONLY)) {
error = EROFS;
goto end;
}
tx = dmu_tx_create(zv->zv_objset);
dmu_tx_hold_bonus(tx, ZVOL_OBJ);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
} else {
error = dmu_object_set_blocksize(zv->zv_objset, ZVOL_OBJ,
volblocksize, 0, tx);
if (error == ENOTSUP)
error = EBUSY;
dmu_tx_commit(tx);
/* XXX: Not supported. */
#if 0
if (error == 0)
zv->zv_provider->sectorsize = zc->zc_volblocksize;
#endif
}
end:
g_topology_unlock();
PICKUP_GIANT();
return (error);
}
void
zvol_get_done(dmu_buf_t *db, void *vzgd)
{
zgd_t *zgd = (zgd_t *)vzgd;
rl_t *rl = zgd->zgd_rl;
dmu_buf_rele(db, vzgd);
zfs_range_unlock(rl);
zil_add_vdev(zgd->zgd_zilog, DVA_GET_VDEV(BP_IDENTITY(zgd->zgd_bp)));
kmem_free(zgd, sizeof (zgd_t));
}
/*
* Get data to generate a TX_WRITE intent log record.
*/
static int
zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
{
zvol_state_t *zv = arg;
objset_t *os = zv->zv_objset;
dmu_buf_t *db;
rl_t *rl;
zgd_t *zgd;
uint64_t boff; /* block starting offset */
int dlen = lr->lr_length; /* length of user data */
int error;
ASSERT(zio);
ASSERT(dlen != 0);
/*
* Write records come in two flavors: immediate and indirect.
* For small writes it's cheaper to store the data with the
* log record (immediate); for large writes it's cheaper to
* sync the data and get a pointer to it (indirect) so that
* we don't have to write the data twice.
*/
if (buf != NULL) /* immediate write */
return (dmu_read(os, ZVOL_OBJ, lr->lr_offset, dlen, buf));
zgd = (zgd_t *)kmem_alloc(sizeof (zgd_t), KM_SLEEP);
zgd->zgd_zilog = zv->zv_zilog;
zgd->zgd_bp = &lr->lr_blkptr;
/*
* Lock the range of the block to ensure that when the data is
* written out and it's checksum is being calculated that no other
* thread can change the block.
*/
boff = P2ALIGN_TYPED(lr->lr_offset, zv->zv_volblocksize, uint64_t);
rl = zfs_range_lock(&zv->zv_znode, boff, zv->zv_volblocksize,
RL_READER);
zgd->zgd_rl = rl;
VERIFY(0 == dmu_buf_hold(os, ZVOL_OBJ, lr->lr_offset, zgd, &db));
error = dmu_sync(zio, db, &lr->lr_blkptr,
lr->lr_common.lrc_txg, zvol_get_done, zgd);
if (error == 0)
zil_add_vdev(zv->zv_zilog,
DVA_GET_VDEV(BP_IDENTITY(&lr->lr_blkptr)));
/*
* If we get EINPROGRESS, then we need to wait for a
* write IO initiated by dmu_sync() to complete before
* we can release this dbuf. We will finish everything
* up in the zvol_get_done() callback.
*/
if (error == EINPROGRESS)
return (0);
dmu_buf_rele(db, zgd);
zfs_range_unlock(rl);
kmem_free(zgd, sizeof (zgd_t));
return (error);
}
int
zvol_busy(void)
{
return (zvol_minors != 0);
}
void
zvol_init(void)
{
ZFS_LOG(1, "ZVOL Initialized.");
}
void
zvol_fini(void)
{
ZFS_LOG(1, "ZVOL Deinitialized.");
}
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