--- /dev/null
+/*
+ * 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) 2008-2010 Lawrence Livermore National Security, LLC.
+ * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ * Rewritten for Linux by Brian Behlendorf <behlendorf1@llnl.gov>.
+ * LLNL-CODE-403049.
+ *
+ * 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/<pool_name>/<dataset_name>
+ *
+ * Volumes are persistent through reboot and module load. No user command
+ * needs to be run before opening and using a device.
+ *
+ * Copyright (c) 2016 Actifio, Inc. All rights reserved.
+ */
+
+#include <sys/dbuf.h>
+#include <sys/dmu_traverse.h>
+#include <sys/dsl_dataset.h>
+#include <sys/dsl_prop.h>
+#include <sys/dsl_dir.h>
+#include <sys/zap.h>
+#include <sys/zfeature.h>
+#include <sys/zil_impl.h>
+#include <sys/dmu_tx.h>
+#include <sys/zio.h>
+#include <sys/zfs_rlock.h>
+#include <sys/zfs_znode.h>
+#include <sys/spa_impl.h>
+#include <sys/zvol.h>
+#include <linux/blkdev_compat.h>
+
+unsigned int zvol_inhibit_dev = 0;
+unsigned int zvol_major = ZVOL_MAJOR;
+unsigned int zvol_prefetch_bytes = (128 * 1024);
+unsigned long zvol_max_discard_blocks = 16384;
+
+static kmutex_t zvol_state_lock;
+static list_t zvol_state_list;
+static char *zvol_tag = "zvol_tag";
+
+/*
+ * The in-core state of each volume.
+ */
+typedef struct zvol_state {
+ char zv_name[MAXNAMELEN]; /* name */
+ uint64_t zv_volsize; /* advertised space */
+ uint64_t zv_volblocksize; /* volume block size */
+ objset_t *zv_objset; /* objset handle */
+ uint32_t zv_flags; /* ZVOL_* flags */
+ uint32_t zv_open_count; /* open counts */
+ uint32_t zv_changed; /* disk changed */
+ zilog_t *zv_zilog; /* ZIL handle */
+ zfs_rlock_t zv_range_lock; /* range lock */
+ dmu_buf_t *zv_dbuf; /* bonus handle */
+ dev_t zv_dev; /* device id */
+ struct gendisk *zv_disk; /* generic disk */
+ struct request_queue *zv_queue; /* request queue */
+ spinlock_t zv_lock; /* request queue lock */
+ list_node_t zv_next; /* next zvol_state_t linkage */
+} zvol_state_t;
+
+typedef enum {
+ ZVOL_ASYNC_CREATE_MINORS,
+ ZVOL_ASYNC_REMOVE_MINORS,
+ ZVOL_ASYNC_RENAME_MINORS,
+ ZVOL_ASYNC_SET_SNAPDEV,
+ ZVOL_ASYNC_MAX
+} zvol_async_op_t;
+
+typedef struct {
+ zvol_async_op_t op;
+ char pool[MAXNAMELEN];
+ char name1[MAXNAMELEN];
+ char name2[MAXNAMELEN];
+ zprop_source_t source;
+ uint64_t snapdev;
+} zvol_task_t;
+
+#define ZVOL_RDONLY 0x1
+
+/*
+ * Find the next available range of ZVOL_MINORS minor numbers. The
+ * zvol_state_list is kept in ascending minor order so we simply need
+ * to scan the list for the first gap in the sequence. This allows us
+ * to recycle minor number as devices are created and removed.
+ */
+static int
+zvol_find_minor(unsigned *minor)
+{
+ zvol_state_t *zv;
+
+ *minor = 0;
+ ASSERT(MUTEX_HELD(&zvol_state_lock));
+ for (zv = list_head(&zvol_state_list); zv != NULL;
+ zv = list_next(&zvol_state_list, zv), *minor += ZVOL_MINORS) {
+ if (MINOR(zv->zv_dev) != MINOR(*minor))
+ break;
+ }
+
+ /* All minors are in use */
+ if (*minor >= (1 << MINORBITS))
+ return (SET_ERROR(ENXIO));
+
+ return (0);
+}
+
+/*
+ * Find a zvol_state_t given the full major+minor dev_t.
+ */
+static zvol_state_t *
+zvol_find_by_dev(dev_t dev)
+{
+ zvol_state_t *zv;
+
+ ASSERT(MUTEX_HELD(&zvol_state_lock));
+ for (zv = list_head(&zvol_state_list); zv != NULL;
+ zv = list_next(&zvol_state_list, zv)) {
+ if (zv->zv_dev == dev)
+ return (zv);
+ }
+
+ return (NULL);
+}
+
+/*
+ * Find a zvol_state_t given the name provided at zvol_alloc() time.
+ */
+static zvol_state_t *
+zvol_find_by_name(const char *name)
+{
+ zvol_state_t *zv;
+
+ ASSERT(MUTEX_HELD(&zvol_state_lock));
+ for (zv = list_head(&zvol_state_list); zv != NULL;
+ zv = list_next(&zvol_state_list, zv)) {
+ if (strncmp(zv->zv_name, name, MAXNAMELEN) == 0)
+ return (zv);
+ }
+
+ return (NULL);
+}
+
+
+/*
+ * Given a path, return TRUE if path is a ZVOL.
+ */
+boolean_t
+zvol_is_zvol(const char *device)
+{
+ struct block_device *bdev;
+ unsigned int major;
+
+ bdev = vdev_lookup_bdev(device);
+ if (IS_ERR(bdev))
+ return (B_FALSE);
+
+ major = MAJOR(bdev->bd_dev);
+ bdput(bdev);
+
+ if (major == zvol_major)
+ return (B_TRUE);
+
+ return (B_FALSE);
+}
+
+/*
+ * ZFS_IOC_CREATE callback handles dmu zvol and zap object creation.
+ */
+void
+zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx)
+{
+ zfs_creat_t *zct = arg;
+ nvlist_t *nvprops = zct->zct_props;
+ int error;
+ uint64_t volblocksize, volsize;
+
+ VERIFY(nvlist_lookup_uint64(nvprops,
+ zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0);
+ if (nvlist_lookup_uint64(nvprops,
+ zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0)
+ volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE);
+
+ /*
+ * These properties must be removed from the list so the generic
+ * property setting step won't apply to them.
+ */
+ VERIFY(nvlist_remove_all(nvprops,
+ zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0);
+ (void) nvlist_remove_all(nvprops,
+ 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);
+}
+
+/*
+ * ZFS_IOC_OBJSET_STATS entry point.
+ */
+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 (SET_ERROR(error));
+
+ dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val);
+ doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
+ 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);
+ }
+
+ kmem_free(doi, sizeof (dmu_object_info_t));
+
+ return (SET_ERROR(error));
+}
+
+static void
+zvol_size_changed(zvol_state_t *zv, uint64_t volsize)
+{
+ struct block_device *bdev;
+
+ bdev = bdget_disk(zv->zv_disk, 0);
+ if (bdev == NULL)
+ return;
+/*
+ * 2.6.28 API change
+ * Added check_disk_size_change() helper function.
+ */
+#ifdef HAVE_CHECK_DISK_SIZE_CHANGE
+ set_capacity(zv->zv_disk, volsize >> 9);
+ zv->zv_volsize = volsize;
+ check_disk_size_change(zv->zv_disk, bdev);
+#else
+ zv->zv_volsize = volsize;
+ zv->zv_changed = 1;
+ (void) check_disk_change(bdev);
+#endif /* HAVE_CHECK_DISK_SIZE_CHANGE */
+
+ bdput(bdev);
+}
+
+/*
+ * Sanity check volume size.
+ */
+int
+zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
+{
+ if (volsize == 0)
+ return (SET_ERROR(EINVAL));
+
+ if (volsize % blocksize != 0)
+ return (SET_ERROR(EINVAL));
+
+#ifdef _ILP32
+ if (volsize - 1 > MAXOFFSET_T)
+ return (SET_ERROR(EOVERFLOW));
+#endif
+ return (0);
+}
+
+/*
+ * Ensure the zap is flushed then inform the VFS of the capacity change.
+ */
+static int
+zvol_update_volsize(uint64_t volsize, objset_t *os)
+{
+ dmu_tx_t *tx;
+ int error;
+
+ ASSERT(MUTEX_HELD(&zvol_state_lock));
+
+ tx = dmu_tx_create(os);
+ dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
+ error = dmu_tx_assign(tx, TXG_WAIT);
+ if (error) {
+ dmu_tx_abort(tx);
+ return (SET_ERROR(error));
+ }
+
+ error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1,
+ &volsize, tx);
+ dmu_tx_commit(tx);
+
+ if (error == 0)
+ error = dmu_free_long_range(os,
+ ZVOL_OBJ, volsize, DMU_OBJECT_END);
+
+ return (error);
+}
+
+static int
+zvol_update_live_volsize(zvol_state_t *zv, uint64_t volsize)
+{
+ zvol_size_changed(zv, volsize);
+
+ /*
+ * We should post a event here describing the expansion. However,
+ * the zfs_ereport_post() interface doesn't nicely support posting
+ * events for zvols, it assumes events relate to vdevs or zios.
+ */
+
+ return (0);
+}
+
+/*
+ * Set ZFS_PROP_VOLSIZE set entry point.
+ */
+int
+zvol_set_volsize(const char *name, uint64_t volsize)
+{
+ zvol_state_t *zv = NULL;
+ objset_t *os = NULL;
+ int error;
+ dmu_object_info_t *doi;
+ uint64_t readonly;
+ boolean_t owned = B_FALSE;
+
+ error = dsl_prop_get_integer(name,
+ zfs_prop_to_name(ZFS_PROP_READONLY), &readonly, NULL);
+ if (error != 0)
+ return (SET_ERROR(error));
+ if (readonly)
+ return (SET_ERROR(EROFS));
+
+ mutex_enter(&zvol_state_lock);
+ zv = zvol_find_by_name(name);
+
+ if (zv == NULL || zv->zv_objset == NULL) {
+ if ((error = dmu_objset_own(name, DMU_OST_ZVOL, B_FALSE,
+ FTAG, &os)) != 0) {
+ mutex_exit(&zvol_state_lock);
+ return (SET_ERROR(error));
+ }
+ owned = B_TRUE;
+ if (zv != NULL)
+ zv->zv_objset = os;
+ } else {
+ os = zv->zv_objset;
+ }
+
+ doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
+
+ if ((error = dmu_object_info(os, ZVOL_OBJ, doi)) ||
+ (error = zvol_check_volsize(volsize, doi->doi_data_block_size)))
+ goto out;
+
+ error = zvol_update_volsize(volsize, os);
+ kmem_free(doi, sizeof (dmu_object_info_t));
+
+ if (error == 0 && zv != NULL)
+ error = zvol_update_live_volsize(zv, volsize);
+out:
+ if (owned) {
+ dmu_objset_disown(os, FTAG);
+ if (zv != NULL)
+ zv->zv_objset = NULL;
+ }
+ mutex_exit(&zvol_state_lock);
+ return (error);
+}
+
+/*
+ * Sanity check volume block size.
+ */
+int
+zvol_check_volblocksize(const char *name, uint64_t volblocksize)
+{
+ /* Record sizes above 128k need the feature to be enabled */
+ if (volblocksize > SPA_OLD_MAXBLOCKSIZE) {
+ spa_t *spa;
+ int error;
+
+ if ((error = spa_open(name, &spa, FTAG)) != 0)
+ return (error);
+
+ if (!spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS)) {
+ spa_close(spa, FTAG);
+ return (SET_ERROR(ENOTSUP));
+ }
+
+ /*
+ * We don't allow setting the property above 1MB,
+ * unless the tunable has been changed.
+ */
+ if (volblocksize > zfs_max_recordsize)
+ return (SET_ERROR(EDOM));
+
+ spa_close(spa, FTAG);
+ }
+
+ if (volblocksize < SPA_MINBLOCKSIZE ||
+ volblocksize > SPA_MAXBLOCKSIZE ||
+ !ISP2(volblocksize))
+ return (SET_ERROR(EDOM));
+
+ return (0);
+}
+
+/*
+ * Set ZFS_PROP_VOLBLOCKSIZE set entry point.
+ */
+int
+zvol_set_volblocksize(const char *name, uint64_t volblocksize)
+{
+ zvol_state_t *zv;
+ dmu_tx_t *tx;
+ int error;
+
+ mutex_enter(&zvol_state_lock);
+
+ zv = zvol_find_by_name(name);
+ if (zv == NULL) {
+ error = SET_ERROR(ENXIO);
+ goto out;
+ }
+
+ if (zv->zv_flags & ZVOL_RDONLY) {
+ error = SET_ERROR(EROFS);
+ goto out;
+ }
+
+ 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 = SET_ERROR(EBUSY);
+ dmu_tx_commit(tx);
+ if (error == 0)
+ zv->zv_volblocksize = volblocksize;
+ }
+out:
+ mutex_exit(&zvol_state_lock);
+
+ return (SET_ERROR(error));
+}
+
+/*
+ * 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, TXG_WAIT);
+ if (error) {
+ dmu_tx_abort(tx);
+ } else {
+ dmu_write(os, ZVOL_OBJ, off, len, data, tx);
+ dmu_tx_commit(tx);
+ }
+
+ return (SET_ERROR(error));
+}
+
+static int
+zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap)
+{
+ return (SET_ERROR(ENOTSUP));
+}
+
+/*
+ * Callback vectors for replaying records.
+ * Only TX_WRITE is needed for zvol.
+ */
+zil_replay_func_t zvol_replay_vector[TX_MAX_TYPE] = {
+ (zil_replay_func_t)zvol_replay_err, /* no such transaction type */
+ (zil_replay_func_t)zvol_replay_err, /* TX_CREATE */
+ (zil_replay_func_t)zvol_replay_err, /* TX_MKDIR */
+ (zil_replay_func_t)zvol_replay_err, /* TX_MKXATTR */
+ (zil_replay_func_t)zvol_replay_err, /* TX_SYMLINK */
+ (zil_replay_func_t)zvol_replay_err, /* TX_REMOVE */
+ (zil_replay_func_t)zvol_replay_err, /* TX_RMDIR */
+ (zil_replay_func_t)zvol_replay_err, /* TX_LINK */
+ (zil_replay_func_t)zvol_replay_err, /* TX_RENAME */
+ (zil_replay_func_t)zvol_replay_write, /* TX_WRITE */
+ (zil_replay_func_t)zvol_replay_err, /* TX_TRUNCATE */
+ (zil_replay_func_t)zvol_replay_err, /* TX_SETATTR */
+ (zil_replay_func_t)zvol_replay_err, /* TX_ACL */
+};
+
+/*
+ * 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, uint64_t offset,
+ uint64_t size, int sync)
+{
+ uint32_t blocksize = zv->zv_volblocksize;
+ zilog_t *zilog = zv->zv_zilog;
+ boolean_t slogging;
+ ssize_t immediate_write_sz;
+
+ if (zil_replaying(zilog, tx))
+ return;
+
+ immediate_write_sz = (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
+ ? 0 : zvol_immediate_write_sz;
+ slogging = spa_has_slogs(zilog->zl_spa) &&
+ (zilog->zl_logbias == ZFS_LOGBIAS_LATENCY);
+
+ while (size) {
+ itx_t *itx;
+ lr_write_t *lr;
+ ssize_t len;
+ itx_wr_state_t write_state;
+
+ /*
+ * Unlike zfs_log_write() we can be called with
+ * up to DMU_MAX_ACCESS/2 (5MB) writes.
+ */
+ if (blocksize > immediate_write_sz && !slogging &&
+ size >= blocksize && offset % blocksize == 0) {
+ write_state = WR_INDIRECT; /* uses dmu_sync */
+ len = blocksize;
+ } else if (sync) {
+ write_state = WR_COPIED;
+ len = MIN(ZIL_MAX_LOG_DATA, size);
+ } else {
+ write_state = WR_NEED_COPY;
+ len = MIN(ZIL_MAX_LOG_DATA, size);
+ }
+
+ itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
+ (write_state == WR_COPIED ? len : 0));
+ lr = (lr_write_t *)&itx->itx_lr;
+ if (write_state == WR_COPIED && dmu_read(zv->zv_objset,
+ ZVOL_OBJ, offset, len, lr+1, DMU_READ_NO_PREFETCH) != 0) {
+ zil_itx_destroy(itx);
+ itx = zil_itx_create(TX_WRITE, sizeof (*lr));
+ lr = (lr_write_t *)&itx->itx_lr;
+ write_state = WR_NEED_COPY;
+ }
+
+ itx->itx_wr_state = write_state;
+ if (write_state == WR_NEED_COPY)
+ itx->itx_sod += len;
+ lr->lr_foid = ZVOL_OBJ;
+ lr->lr_offset = offset;
+ lr->lr_length = len;
+ lr->lr_blkoff = 0;
+ BP_ZERO(&lr->lr_blkptr);
+
+ itx->itx_private = zv;
+ itx->itx_sync = sync;
+
+ (void) zil_itx_assign(zilog, itx, tx);
+
+ offset += len;
+ size -= len;
+ }
+}
+
+static int
+zvol_write(struct bio *bio)
+{
+ zvol_state_t *zv = bio->bi_bdev->bd_disk->private_data;
+ uint64_t offset = BIO_BI_SECTOR(bio) << 9;
+ uint64_t size = BIO_BI_SIZE(bio);
+ int error = 0;
+ dmu_tx_t *tx;
+ rl_t *rl;
+
+ ASSERT(zv && zv->zv_open_count > 0);
+
+ if (bio_is_flush(bio))
+ zil_commit(zv->zv_zilog, ZVOL_OBJ);
+
+ /*
+ * Some requests are just for flush and nothing else.
+ */
+ if (size == 0)
+ goto out;
+
+ rl = zfs_range_lock(&zv->zv_range_lock, offset, size, RL_WRITER);
+
+ tx = dmu_tx_create(zv->zv_objset);
+ dmu_tx_hold_write(tx, ZVOL_OBJ, offset, size);
+
+ /* This will only fail for ENOSPC */
+ error = dmu_tx_assign(tx, TXG_WAIT);
+ if (error) {
+ dmu_tx_abort(tx);
+ zfs_range_unlock(rl);
+ goto out;
+ }
+
+ error = dmu_write_bio(zv->zv_objset, ZVOL_OBJ, bio, tx);
+ if (error == 0)
+ zvol_log_write(zv, tx, offset, size,
+ !!(bio_is_fua(bio)));
+
+ dmu_tx_commit(tx);
+ zfs_range_unlock(rl);
+
+ if ((bio_is_fua(bio)) ||
+ zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS)
+ zil_commit(zv->zv_zilog, ZVOL_OBJ);
+
+out:
+ return (error);
+}
+
+static int
+zvol_discard(struct bio *bio)
+{
+ zvol_state_t *zv = bio->bi_bdev->bd_disk->private_data;
+ uint64_t start = BIO_BI_SECTOR(bio) << 9;
+ uint64_t size = BIO_BI_SIZE(bio);
+ uint64_t end = start + size;
+ int error;
+ rl_t *rl;
+
+ ASSERT(zv && zv->zv_open_count > 0);
+
+ if (end > zv->zv_volsize)
+ return (SET_ERROR(EIO));
+
+ /*
+ * Align the request to volume block boundaries when a secure erase is
+ * not required. This will prevent dnode_free_range() from zeroing out
+ * the unaligned parts which is slow (read-modify-write) and useless
+ * since we are not freeing any space by doing so.
+ */
+ if (!bio_is_secure_erase(bio)) {
+ start = P2ROUNDUP(start, zv->zv_volblocksize);
+ end = P2ALIGN(end, zv->zv_volblocksize);
+ size = end - start;
+ }
+
+ if (start >= end)
+ return (0);
+
+ rl = zfs_range_lock(&zv->zv_range_lock, start, size, RL_WRITER);
+
+ error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, start, size);
+
+ /*
+ * TODO: maybe we should add the operation to the log.
+ */
+ zfs_range_unlock(rl);
+
+ return (error);
+}
+
+static int
+zvol_read(struct bio *bio)
+{
+ zvol_state_t *zv = bio->bi_bdev->bd_disk->private_data;
+ uint64_t offset = BIO_BI_SECTOR(bio) << 9;
+ uint64_t len = BIO_BI_SIZE(bio);
+ int error;
+ rl_t *rl;
+
+ ASSERT(zv && zv->zv_open_count > 0);
+
+ if (len == 0)
+ return (0);
+
+ rl = zfs_range_lock(&zv->zv_range_lock, offset, len, RL_READER);
+
+ error = dmu_read_bio(zv->zv_objset, ZVOL_OBJ, bio);
+
+ zfs_range_unlock(rl);
+
+ /* convert checksum errors into IO errors */
+ if (error == ECKSUM)
+ error = SET_ERROR(EIO);
+
+ return (error);
+}
+
+static MAKE_REQUEST_FN_RET
+zvol_request(struct request_queue *q, struct bio *bio)
+{
+ zvol_state_t *zv = q->queuedata;
+ fstrans_cookie_t cookie = spl_fstrans_mark();
+ uint64_t offset = BIO_BI_SECTOR(bio);
+ unsigned int sectors = bio_sectors(bio);
+ int rw = bio_data_dir(bio);
+#ifdef HAVE_GENERIC_IO_ACCT
+ unsigned long start = jiffies;
+#endif
+ int error = 0;
+
+ if (bio_has_data(bio) && offset + sectors >
+ get_capacity(zv->zv_disk)) {
+ printk(KERN_INFO
+ "%s: bad access: block=%llu, count=%lu\n",
+ zv->zv_disk->disk_name,
+ (long long unsigned)offset,
+ (long unsigned)sectors);
+ error = SET_ERROR(EIO);
+ goto out1;
+ }
+
+ generic_start_io_acct(rw, sectors, &zv->zv_disk->part0);
+
+ if (rw == WRITE) {
+ if (unlikely(zv->zv_flags & ZVOL_RDONLY)) {
+ error = SET_ERROR(EROFS);
+ goto out2;
+ }
+
+ if (bio_is_discard(bio) || bio_is_secure_erase(bio)) {
+ error = zvol_discard(bio);
+ goto out2;
+ }
+
+ error = zvol_write(bio);
+ } else
+ error = zvol_read(bio);
+
+out2:
+ generic_end_io_acct(rw, &zv->zv_disk->part0, start);
+out1:
+ BIO_END_IO(bio, -error);
+ spl_fstrans_unmark(cookie);
+#ifdef HAVE_MAKE_REQUEST_FN_RET_INT
+ return (0);
+#elif defined(HAVE_MAKE_REQUEST_FN_RET_QC)
+ return (BLK_QC_T_NONE);
+#endif
+}
+
+static void
+zvol_get_done(zgd_t *zgd, int error)
+{
+ if (zgd->zgd_db)
+ dmu_buf_rele(zgd->zgd_db, zgd);
+
+ zfs_range_unlock(zgd->zgd_rl);
+
+ if (error == 0 && zgd->zgd_bp)
+ zil_add_block(zgd->zgd_zilog, 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;
+ uint64_t object = ZVOL_OBJ;
+ uint64_t offset = lr->lr_offset;
+ uint64_t size = lr->lr_length;
+ blkptr_t *bp = &lr->lr_blkptr;
+ dmu_buf_t *db;
+ zgd_t *zgd;
+ int error;
+
+ ASSERT(zio != NULL);
+ ASSERT(size != 0);
+
+ zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
+ zgd->zgd_zilog = zv->zv_zilog;
+ zgd->zgd_rl = zfs_range_lock(&zv->zv_range_lock, offset, size,
+ RL_READER);
+
+ /*
+ * 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 */
+ error = dmu_read(os, object, offset, size, buf,
+ DMU_READ_NO_PREFETCH);
+ } else {
+ size = zv->zv_volblocksize;
+ offset = P2ALIGN_TYPED(offset, size, uint64_t);
+ error = dmu_buf_hold(os, object, offset, zgd, &db,
+ DMU_READ_NO_PREFETCH);
+ if (error == 0) {
+ blkptr_t *obp = dmu_buf_get_blkptr(db);
+ if (obp) {
+ ASSERT(BP_IS_HOLE(bp));
+ *bp = *obp;
+ }
+
+ zgd->zgd_db = db;
+ zgd->zgd_bp = &lr->lr_blkptr;
+
+ ASSERT(db != NULL);
+ ASSERT(db->db_offset == offset);
+ ASSERT(db->db_size == size);
+
+ error = dmu_sync(zio, lr->lr_common.lrc_txg,
+ zvol_get_done, zgd);
+
+ if (error == 0)
+ return (0);
+ }
+ }
+
+ zvol_get_done(zgd, error);
+
+ return (SET_ERROR(error));
+}
+
+/*
+ * The zvol_state_t's are inserted in increasing MINOR(dev_t) order.
+ */
+static void
+zvol_insert(zvol_state_t *zv_insert)
+{
+ zvol_state_t *zv = NULL;
+
+ ASSERT(MUTEX_HELD(&zvol_state_lock));
+ ASSERT3U(MINOR(zv_insert->zv_dev) & ZVOL_MINOR_MASK, ==, 0);
+ for (zv = list_head(&zvol_state_list); zv != NULL;
+ zv = list_next(&zvol_state_list, zv)) {
+ if (MINOR(zv->zv_dev) > MINOR(zv_insert->zv_dev))
+ break;
+ }
+
+ list_insert_before(&zvol_state_list, zv, zv_insert);
+}
+
+/*
+ * Simply remove the zvol from to list of zvols.
+ */
+static void
+zvol_remove(zvol_state_t *zv_remove)
+{
+ ASSERT(MUTEX_HELD(&zvol_state_lock));
+ list_remove(&zvol_state_list, zv_remove);
+}
+
+static int
+zvol_first_open(zvol_state_t *zv)
+{
+ objset_t *os;
+ uint64_t volsize;
+ int error;
+ uint64_t ro;
+
+ /* lie and say we're read-only */
+ error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, 1, zvol_tag, &os);
+ if (error)
+ return (SET_ERROR(-error));
+
+ zv->zv_objset = os;
+
+ error = dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL);
+ if (error)
+ goto out_owned;
+
+ error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
+ if (error)
+ goto out_owned;
+
+ error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf);
+ if (error)
+ goto out_owned;
+
+ set_capacity(zv->zv_disk, volsize >> 9);
+ zv->zv_volsize = volsize;
+ zv->zv_zilog = zil_open(os, zvol_get_data);
+
+ if (ro || dmu_objset_is_snapshot(os) ||
+ !spa_writeable(dmu_objset_spa(os))) {
+ set_disk_ro(zv->zv_disk, 1);
+ zv->zv_flags |= ZVOL_RDONLY;
+ } else {
+ set_disk_ro(zv->zv_disk, 0);
+ zv->zv_flags &= ~ZVOL_RDONLY;
+ }
+
+out_owned:
+ if (error) {
+ dmu_objset_disown(os, zvol_tag);
+ zv->zv_objset = NULL;
+ }
+
+ return (SET_ERROR(-error));
+}
+
+static void
+zvol_last_close(zvol_state_t *zv)
+{
+ zil_close(zv->zv_zilog);
+ zv->zv_zilog = NULL;
+
+ dmu_buf_rele(zv->zv_dbuf, zvol_tag);
+ zv->zv_dbuf = NULL;
+
+ /*
+ * Evict cached data
+ */
+ if (dsl_dataset_is_dirty(dmu_objset_ds(zv->zv_objset)) &&
+ !(zv->zv_flags & ZVOL_RDONLY))
+ txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
+ (void) dmu_objset_evict_dbufs(zv->zv_objset);
+
+ dmu_objset_disown(zv->zv_objset, zvol_tag);
+ zv->zv_objset = NULL;
+}
+
+static int
+zvol_open(struct block_device *bdev, fmode_t flag)
+{
+ zvol_state_t *zv;
+ int error = 0, drop_mutex = 0;
+
+ /*
+ * If the caller is already holding the mutex do not take it
+ * again, this will happen as part of zvol_create_minor_impl().
+ * Once add_disk() is called the device is live and the kernel
+ * will attempt to open it to read the partition information.
+ */
+ if (!mutex_owned(&zvol_state_lock)) {
+ mutex_enter(&zvol_state_lock);
+ drop_mutex = 1;
+ }
+
+ /*
+ * Obtain a copy of private_data under the lock to make sure
+ * that either the result of zvol_freeg() setting
+ * bdev->bd_disk->private_data to NULL is observed, or zvol_free()
+ * is not called on this zv because of the positive zv_open_count.
+ */
+ zv = bdev->bd_disk->private_data;
+ if (zv == NULL) {
+ error = -ENXIO;
+ goto out_mutex;
+ }
+
+ if (zv->zv_open_count == 0) {
+ error = zvol_first_open(zv);
+ if (error)
+ goto out_mutex;
+ }
+
+ if ((flag & FMODE_WRITE) && (zv->zv_flags & ZVOL_RDONLY)) {
+ error = -EROFS;
+ goto out_open_count;
+ }
+
+ zv->zv_open_count++;
+
+ check_disk_change(bdev);
+
+out_open_count:
+ if (zv->zv_open_count == 0)
+ zvol_last_close(zv);
+
+out_mutex:
+ if (drop_mutex)
+ mutex_exit(&zvol_state_lock);
+
+ return (SET_ERROR(error));
+}
+
+#ifdef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
+static void
+#else
+static int
+#endif
+zvol_release(struct gendisk *disk, fmode_t mode)
+{
+ zvol_state_t *zv = disk->private_data;
+ int drop_mutex = 0;
+
+ ASSERT(zv && zv->zv_open_count > 0);
+
+ if (!mutex_owned(&zvol_state_lock)) {
+ mutex_enter(&zvol_state_lock);
+ drop_mutex = 1;
+ }
+
+ zv->zv_open_count--;
+ if (zv->zv_open_count == 0)
+ zvol_last_close(zv);
+
+ if (drop_mutex)
+ mutex_exit(&zvol_state_lock);
+
+#ifndef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
+ return (0);
+#endif
+}
+
+static int
+zvol_ioctl(struct block_device *bdev, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ zvol_state_t *zv = bdev->bd_disk->private_data;
+ int error = 0;
+
+ ASSERT(zv && zv->zv_open_count > 0);
+
+ switch (cmd) {
+ case BLKFLSBUF:
+ zil_commit(zv->zv_zilog, ZVOL_OBJ);
+ break;
+ case BLKZNAME:
+ error = copy_to_user((void *)arg, zv->zv_name, MAXNAMELEN);
+ break;
+
+ default:
+ error = -ENOTTY;
+ break;
+
+ }
+
+ return (SET_ERROR(error));
+}
+
+#ifdef CONFIG_COMPAT
+static int
+zvol_compat_ioctl(struct block_device *bdev, fmode_t mode,
+ unsigned cmd, unsigned long arg)
+{
+ return (zvol_ioctl(bdev, mode, cmd, arg));
+}
+#else
+#define zvol_compat_ioctl NULL
+#endif
+
+static int zvol_media_changed(struct gendisk *disk)
+{
+ zvol_state_t *zv = disk->private_data;
+
+ ASSERT(zv && zv->zv_open_count > 0);
+
+ return (zv->zv_changed);
+}
+
+static int zvol_revalidate_disk(struct gendisk *disk)
+{
+ zvol_state_t *zv = disk->private_data;
+
+ ASSERT(zv && zv->zv_open_count > 0);
+
+ zv->zv_changed = 0;
+ set_capacity(zv->zv_disk, zv->zv_volsize >> 9);
+
+ return (0);
+}
+
+/*
+ * Provide a simple virtual geometry for legacy compatibility. For devices
+ * smaller than 1 MiB a small head and sector count is used to allow very
+ * tiny devices. For devices over 1 Mib a standard head and sector count
+ * is used to keep the cylinders count reasonable.
+ */
+static int
+zvol_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+ zvol_state_t *zv = bdev->bd_disk->private_data;
+ sector_t sectors;
+
+ ASSERT(zv && zv->zv_open_count > 0);
+
+ sectors = get_capacity(zv->zv_disk);
+
+ if (sectors > 2048) {
+ geo->heads = 16;
+ geo->sectors = 63;
+ } else {
+ geo->heads = 2;
+ geo->sectors = 4;
+ }
+
+ geo->start = 0;
+ geo->cylinders = sectors / (geo->heads * geo->sectors);
+
+ return (0);
+}
+
+static struct kobject *
+zvol_probe(dev_t dev, int *part, void *arg)
+{
+ zvol_state_t *zv;
+ struct kobject *kobj;
+
+ mutex_enter(&zvol_state_lock);
+ zv = zvol_find_by_dev(dev);
+ kobj = zv ? get_disk(zv->zv_disk) : NULL;
+ mutex_exit(&zvol_state_lock);
+
+ return (kobj);
+}
+
+#ifdef HAVE_BDEV_BLOCK_DEVICE_OPERATIONS
+static struct block_device_operations zvol_ops = {
+ .open = zvol_open,
+ .release = zvol_release,
+ .ioctl = zvol_ioctl,
+ .compat_ioctl = zvol_compat_ioctl,
+ .media_changed = zvol_media_changed,
+ .revalidate_disk = zvol_revalidate_disk,
+ .getgeo = zvol_getgeo,
+ .owner = THIS_MODULE,
+};
+
+#else /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
+
+static int
+zvol_open_by_inode(struct inode *inode, struct file *file)
+{
+ return (zvol_open(inode->i_bdev, file->f_mode));
+}
+
+static int
+zvol_release_by_inode(struct inode *inode, struct file *file)
+{
+ return (zvol_release(inode->i_bdev->bd_disk, file->f_mode));
+}
+
+static int
+zvol_ioctl_by_inode(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ if (file == NULL || inode == NULL)
+ return (SET_ERROR(-EINVAL));
+
+ return (zvol_ioctl(inode->i_bdev, file->f_mode, cmd, arg));
+}
+
+#ifdef CONFIG_COMPAT
+static long
+zvol_compat_ioctl_by_inode(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ if (file == NULL)
+ return (SET_ERROR(-EINVAL));
+
+ return (zvol_compat_ioctl(file->f_dentry->d_inode->i_bdev,
+ file->f_mode, cmd, arg));
+}
+#else
+#define zvol_compat_ioctl_by_inode NULL
+#endif
+
+static struct block_device_operations zvol_ops = {
+ .open = zvol_open_by_inode,
+ .release = zvol_release_by_inode,
+ .ioctl = zvol_ioctl_by_inode,
+ .compat_ioctl = zvol_compat_ioctl_by_inode,
+ .media_changed = zvol_media_changed,
+ .revalidate_disk = zvol_revalidate_disk,
+ .getgeo = zvol_getgeo,
+ .owner = THIS_MODULE,
+};
+#endif /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
+
+/*
+ * Allocate memory for a new zvol_state_t and setup the required
+ * request queue and generic disk structures for the block device.
+ */
+static zvol_state_t *
+zvol_alloc(dev_t dev, const char *name)
+{
+ zvol_state_t *zv;
+
+ zv = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP);
+
+ spin_lock_init(&zv->zv_lock);
+ list_link_init(&zv->zv_next);
+
+ zv->zv_queue = blk_alloc_queue(GFP_ATOMIC);
+ if (zv->zv_queue == NULL)
+ goto out_kmem;
+
+ blk_queue_make_request(zv->zv_queue, zvol_request);
+ blk_queue_set_write_cache(zv->zv_queue, B_TRUE, B_TRUE);
+
+ zv->zv_disk = alloc_disk(ZVOL_MINORS);
+ if (zv->zv_disk == NULL)
+ goto out_queue;
+
+ zv->zv_queue->queuedata = zv;
+ zv->zv_dev = dev;
+ zv->zv_open_count = 0;
+ strlcpy(zv->zv_name, name, MAXNAMELEN);
+
+ zfs_rlock_init(&zv->zv_range_lock);
+
+ zv->zv_disk->major = zvol_major;
+ zv->zv_disk->first_minor = (dev & MINORMASK);
+ zv->zv_disk->fops = &zvol_ops;
+ zv->zv_disk->private_data = zv;
+ zv->zv_disk->queue = zv->zv_queue;
+ snprintf(zv->zv_disk->disk_name, DISK_NAME_LEN, "%s%d",
+ ZVOL_DEV_NAME, (dev & MINORMASK));
+
+ return (zv);
+
+out_queue:
+ blk_cleanup_queue(zv->zv_queue);
+out_kmem:
+ kmem_free(zv, sizeof (zvol_state_t));
+
+ return (NULL);
+}
+
+/*
+ * Cleanup then free a zvol_state_t which was created by zvol_alloc().
+ */
+static void
+zvol_free(zvol_state_t *zv)
+{
+ ASSERT(MUTEX_HELD(&zvol_state_lock));
+ ASSERT(zv->zv_open_count == 0);
+
+ zfs_rlock_destroy(&zv->zv_range_lock);
+
+ zv->zv_disk->private_data = NULL;
+
+ del_gendisk(zv->zv_disk);
+ blk_cleanup_queue(zv->zv_queue);
+ put_disk(zv->zv_disk);
+
+ kmem_free(zv, sizeof (zvol_state_t));
+}
+
+/*
+ * Create a block device minor node and setup the linkage between it
+ * and the specified volume. Once this function returns the block
+ * device is live and ready for use.
+ */
+static int
+zvol_create_minor_impl(const char *name)
+{
+ zvol_state_t *zv;
+ objset_t *os;
+ dmu_object_info_t *doi;
+ uint64_t volsize;
+ uint64_t len;
+ unsigned minor = 0;
+ int error = 0;
+
+ mutex_enter(&zvol_state_lock);
+
+ zv = zvol_find_by_name(name);
+ if (zv) {
+ error = SET_ERROR(EEXIST);
+ goto out;
+ }
+
+ doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
+
+ error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, zvol_tag, &os);
+ if (error)
+ goto out_doi;
+
+ error = dmu_object_info(os, ZVOL_OBJ, doi);
+ if (error)
+ goto out_dmu_objset_disown;
+
+ error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
+ if (error)
+ goto out_dmu_objset_disown;
+
+ error = zvol_find_minor(&minor);
+ if (error)
+ goto out_dmu_objset_disown;
+
+ zv = zvol_alloc(MKDEV(zvol_major, minor), name);
+ if (zv == NULL) {
+ error = SET_ERROR(EAGAIN);
+ goto out_dmu_objset_disown;
+ }
+
+ if (dmu_objset_is_snapshot(os))
+ zv->zv_flags |= ZVOL_RDONLY;
+
+ zv->zv_volblocksize = doi->doi_data_block_size;
+ zv->zv_volsize = volsize;
+ zv->zv_objset = os;
+
+ set_capacity(zv->zv_disk, zv->zv_volsize >> 9);
+
+ blk_queue_max_hw_sectors(zv->zv_queue, (DMU_MAX_ACCESS / 4) >> 9);
+ blk_queue_max_segments(zv->zv_queue, UINT16_MAX);
+ blk_queue_max_segment_size(zv->zv_queue, UINT_MAX);
+ blk_queue_physical_block_size(zv->zv_queue, zv->zv_volblocksize);
+ blk_queue_io_opt(zv->zv_queue, zv->zv_volblocksize);
+ blk_queue_max_discard_sectors(zv->zv_queue,
+ (zvol_max_discard_blocks * zv->zv_volblocksize) >> 9);
+ blk_queue_discard_granularity(zv->zv_queue, zv->zv_volblocksize);
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zv->zv_queue);
+#ifdef QUEUE_FLAG_NONROT
+ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zv->zv_queue);
+#endif
+#ifdef QUEUE_FLAG_ADD_RANDOM
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, zv->zv_queue);
+#endif
+
+ if (spa_writeable(dmu_objset_spa(os))) {
+ if (zil_replay_disable)
+ zil_destroy(dmu_objset_zil(os), B_FALSE);
+ else
+ zil_replay(os, zv, zvol_replay_vector);
+ }
+
+ /*
+ * When udev detects the addition of the device it will immediately
+ * invoke blkid(8) to determine the type of content on the device.
+ * Prefetching the blocks commonly scanned by blkid(8) will speed
+ * up this process.
+ */
+ len = MIN(MAX(zvol_prefetch_bytes, 0), SPA_MAXBLOCKSIZE);
+ if (len > 0) {
+ dmu_prefetch(os, ZVOL_OBJ, 0, len);
+ dmu_prefetch(os, ZVOL_OBJ, volsize - len, len);
+ }
+
+ zv->zv_objset = NULL;
+out_dmu_objset_disown:
+ dmu_objset_disown(os, zvol_tag);
+out_doi:
+ kmem_free(doi, sizeof (dmu_object_info_t));
+out:
+
+ if (error == 0) {
+ zvol_insert(zv);
+ /*
+ * Drop the lock to prevent deadlock with sys_open() ->
+ * zvol_open(), which first takes bd_disk->bd_mutex and then
+ * takes zvol_state_lock, whereas this code path first takes
+ * zvol_state_lock, and then takes bd_disk->bd_mutex.
+ */
+ mutex_exit(&zvol_state_lock);
+ add_disk(zv->zv_disk);
+ } else {
+ mutex_exit(&zvol_state_lock);
+ }
+
+ return (SET_ERROR(error));
+}
+
+/*
+ * Rename a block device minor mode for the specified volume.
+ */
+static void
+zvol_rename_minor(zvol_state_t *zv, const char *newname)
+{
+ int readonly = get_disk_ro(zv->zv_disk);
+
+ ASSERT(MUTEX_HELD(&zvol_state_lock));
+
+ strlcpy(zv->zv_name, newname, sizeof (zv->zv_name));
+
+ /*
+ * The block device's read-only state is briefly changed causing
+ * a KOBJ_CHANGE uevent to be issued. This ensures udev detects
+ * the name change and fixes the symlinks. This does not change
+ * ZVOL_RDONLY in zv->zv_flags so the actual read-only state never
+ * changes. This would normally be done using kobject_uevent() but
+ * that is a GPL-only symbol which is why we need this workaround.
+ */
+ set_disk_ro(zv->zv_disk, !readonly);
+ set_disk_ro(zv->zv_disk, readonly);
+}
+
+
+/*
+ * Mask errors to continue dmu_objset_find() traversal
+ */
+static int
+zvol_create_snap_minor_cb(const char *dsname, void *arg)
+{
+ const char *name = (const char *)arg;
+
+ ASSERT0(MUTEX_HELD(&spa_namespace_lock));
+
+ /* skip the designated dataset */
+ if (name && strcmp(dsname, name) == 0)
+ return (0);
+
+ /* at this point, the dsname should name a snapshot */
+ if (strchr(dsname, '@') == 0) {
+ dprintf("zvol_create_snap_minor_cb(): "
+ "%s is not a shapshot name\n", dsname);
+ } else {
+ (void) zvol_create_minor_impl(dsname);
+ }
+
+ return (0);
+}
+
+/*
+ * Mask errors to continue dmu_objset_find() traversal
+ */
+static int
+zvol_create_minors_cb(const char *dsname, void *arg)
+{
+ uint64_t snapdev;
+ int error;
+
+ ASSERT0(MUTEX_HELD(&spa_namespace_lock));
+
+ error = dsl_prop_get_integer(dsname, "snapdev", &snapdev, NULL);
+ if (error)
+ return (0);
+
+ /*
+ * Given the name and the 'snapdev' property, create device minor nodes
+ * with the linkages to zvols/snapshots as needed.
+ * If the name represents a zvol, create a minor node for the zvol, then
+ * check if its snapshots are 'visible', and if so, iterate over the
+ * snapshots and create device minor nodes for those.
+ */
+ if (strchr(dsname, '@') == 0) {
+ /* create minor for the 'dsname' explicitly */
+ error = zvol_create_minor_impl(dsname);
+ if ((error == 0 || error == EEXIST) &&
+ (snapdev == ZFS_SNAPDEV_VISIBLE)) {
+ fstrans_cookie_t cookie = spl_fstrans_mark();
+ /*
+ * traverse snapshots only, do not traverse children,
+ * and skip the 'dsname'
+ */
+ error = dmu_objset_find((char *)dsname,
+ zvol_create_snap_minor_cb, (void *)dsname,
+ DS_FIND_SNAPSHOTS);
+ spl_fstrans_unmark(cookie);
+ }
+ } else {
+ dprintf("zvol_create_minors_cb(): %s is not a zvol name\n",
+ dsname);
+ }
+
+ return (0);
+}
+
+/*
+ * Create minors for the specified dataset, including children and snapshots.
+ * Pay attention to the 'snapdev' property and iterate over the snapshots
+ * only if they are 'visible'. This approach allows one to assure that the
+ * snapshot metadata is read from disk only if it is needed.
+ *
+ * The name can represent a dataset to be recursively scanned for zvols and
+ * their snapshots, or a single zvol snapshot. If the name represents a
+ * dataset, the scan is performed in two nested stages:
+ * - scan the dataset for zvols, and
+ * - for each zvol, create a minor node, then check if the zvol's snapshots
+ * are 'visible', and only then iterate over the snapshots if needed
+ *
+ * If the name represents a snapshot, a check is perfromed if the snapshot is
+ * 'visible' (which also verifies that the parent is a zvol), and if so,
+ * a minor node for that snapshot is created.
+ */
+static int
+zvol_create_minors_impl(const char *name)
+{
+ int error = 0;
+ fstrans_cookie_t cookie;
+ char *atp, *parent;
+
+ if (zvol_inhibit_dev)
+ return (0);
+
+ parent = kmem_alloc(MAXPATHLEN, KM_SLEEP);
+ (void) strlcpy(parent, name, MAXPATHLEN);
+
+ if ((atp = strrchr(parent, '@')) != NULL) {
+ uint64_t snapdev;
+
+ *atp = '\0';
+ error = dsl_prop_get_integer(parent, "snapdev",
+ &snapdev, NULL);
+
+ if (error == 0 && snapdev == ZFS_SNAPDEV_VISIBLE)
+ error = zvol_create_minor_impl(name);
+ } else {
+ cookie = spl_fstrans_mark();
+ error = dmu_objset_find(parent, zvol_create_minors_cb,
+ NULL, DS_FIND_CHILDREN);
+ spl_fstrans_unmark(cookie);
+ }
+
+ kmem_free(parent, MAXPATHLEN);
+
+ return (SET_ERROR(error));
+}
+
+/*
+ * Remove minors for specified dataset including children and snapshots.
+ */
+static void
+zvol_remove_minors_impl(const char *name)
+{
+ zvol_state_t *zv, *zv_next;
+ int namelen = ((name) ? strlen(name) : 0);
+
+ if (zvol_inhibit_dev)
+ return;
+
+ mutex_enter(&zvol_state_lock);
+
+ for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
+ zv_next = list_next(&zvol_state_list, zv);
+
+ if (name == NULL || strcmp(zv->zv_name, name) == 0 ||
+ (strncmp(zv->zv_name, name, namelen) == 0 &&
+ (zv->zv_name[namelen] == '/' ||
+ zv->zv_name[namelen] == '@'))) {
+
+ /* If in use, leave alone */
+ if (zv->zv_open_count > 0)
+ continue;
+
+ zvol_remove(zv);
+ zvol_free(zv);
+ }
+ }
+
+ mutex_exit(&zvol_state_lock);
+}
+
+/* Remove minor for this specific snapshot only */
+static void
+zvol_remove_minor_impl(const char *name)
+{
+ zvol_state_t *zv, *zv_next;
+
+ if (zvol_inhibit_dev)
+ return;
+
+ if (strchr(name, '@') == NULL)
+ return;
+
+ mutex_enter(&zvol_state_lock);
+
+ for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
+ zv_next = list_next(&zvol_state_list, zv);
+
+ if (strcmp(zv->zv_name, name) == 0) {
+ /* If in use, leave alone */
+ if (zv->zv_open_count > 0)
+ continue;
+ zvol_remove(zv);
+ zvol_free(zv);
+ break;
+ }
+ }
+
+ mutex_exit(&zvol_state_lock);
+}
+
+/*
+ * Rename minors for specified dataset including children and snapshots.
+ */
+static void
+zvol_rename_minors_impl(const char *oldname, const char *newname)
+{
+ zvol_state_t *zv, *zv_next;
+ int oldnamelen, newnamelen;
+ char *name;
+
+ if (zvol_inhibit_dev)
+ return;
+
+ oldnamelen = strlen(oldname);
+ newnamelen = strlen(newname);
+ name = kmem_alloc(MAXNAMELEN, KM_SLEEP);
+
+ mutex_enter(&zvol_state_lock);
+
+ for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
+ zv_next = list_next(&zvol_state_list, zv);
+
+ /* If in use, leave alone */
+ if (zv->zv_open_count > 0)
+ continue;
+
+ if (strcmp(zv->zv_name, oldname) == 0) {
+ zvol_rename_minor(zv, newname);
+ } else if (strncmp(zv->zv_name, oldname, oldnamelen) == 0 &&
+ (zv->zv_name[oldnamelen] == '/' ||
+ zv->zv_name[oldnamelen] == '@')) {
+ snprintf(name, MAXNAMELEN, "%s%c%s", newname,
+ zv->zv_name[oldnamelen],
+ zv->zv_name + oldnamelen + 1);
+ zvol_rename_minor(zv, name);
+ }
+ }
+
+ mutex_exit(&zvol_state_lock);
+
+ kmem_free(name, MAXNAMELEN);
+}
+
+typedef struct zvol_snapdev_cb_arg {
+ uint64_t snapdev;
+} zvol_snapdev_cb_arg_t;
+
+static int
+zvol_set_snapdev_cb(const char *dsname, void *param) {
+ zvol_snapdev_cb_arg_t *arg = param;
+
+ if (strchr(dsname, '@') == NULL)
+ return (0);
+
+ switch (arg->snapdev) {
+ case ZFS_SNAPDEV_VISIBLE:
+ (void) zvol_create_minor_impl(dsname);
+ break;
+ case ZFS_SNAPDEV_HIDDEN:
+ (void) zvol_remove_minor_impl(dsname);
+ break;
+ }
+
+ return (0);
+}
+
+static void
+zvol_set_snapdev_impl(char *name, uint64_t snapdev)
+{
+ zvol_snapdev_cb_arg_t arg = {snapdev};
+ fstrans_cookie_t cookie = spl_fstrans_mark();
+ /*
+ * The zvol_set_snapdev_sync() sets snapdev appropriately
+ * in the dataset hierarchy. Here, we only scan snapshots.
+ */
+ dmu_objset_find(name, zvol_set_snapdev_cb, &arg, DS_FIND_SNAPSHOTS);
+ spl_fstrans_unmark(cookie);
+}
+
+static zvol_task_t *
+zvol_task_alloc(zvol_async_op_t op, const char *name1, const char *name2,
+ uint64_t snapdev)
+{
+ zvol_task_t *task;
+ char *delim;
+
+ /* Never allow tasks on hidden names. */
+ if (name1[0] == '$')
+ return (NULL);
+
+ task = kmem_zalloc(sizeof (zvol_task_t), KM_SLEEP);
+ task->op = op;
+ task->snapdev = snapdev;
+ delim = strchr(name1, '/');
+ strlcpy(task->pool, name1, delim ? (delim - name1 + 1) : MAXNAMELEN);
+
+ strlcpy(task->name1, name1, MAXNAMELEN);
+ if (name2 != NULL)
+ strlcpy(task->name2, name2, MAXNAMELEN);
+
+ return (task);
+}
+
+static void
+zvol_task_free(zvol_task_t *task)
+{
+ kmem_free(task, sizeof (zvol_task_t));
+}
+
+/*
+ * The worker thread function performed asynchronously.
+ */
+static void
+zvol_task_cb(void *param)
+{
+ zvol_task_t *task = (zvol_task_t *)param;
+
+ switch (task->op) {
+ case ZVOL_ASYNC_CREATE_MINORS:
+ (void) zvol_create_minors_impl(task->name1);
+ break;
+ case ZVOL_ASYNC_REMOVE_MINORS:
+ zvol_remove_minors_impl(task->name1);
+ break;
+ case ZVOL_ASYNC_RENAME_MINORS:
+ zvol_rename_minors_impl(task->name1, task->name2);
+ break;
+ case ZVOL_ASYNC_SET_SNAPDEV:
+ zvol_set_snapdev_impl(task->name1, task->snapdev);
+ break;
+ default:
+ VERIFY(0);
+ break;
+ }
+
+ zvol_task_free(task);
+}
+
+typedef struct zvol_set_snapdev_arg {
+ const char *zsda_name;
+ uint64_t zsda_value;
+ zprop_source_t zsda_source;
+ dmu_tx_t *zsda_tx;
+} zvol_set_snapdev_arg_t;
+
+/*
+ * Sanity check the dataset for safe use by the sync task. No additional
+ * conditions are imposed.
+ */
+static int
+zvol_set_snapdev_check(void *arg, dmu_tx_t *tx)
+{
+ zvol_set_snapdev_arg_t *zsda = arg;
+ dsl_pool_t *dp = dmu_tx_pool(tx);
+ dsl_dir_t *dd;
+ int error;
+
+ error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL);
+ if (error != 0)
+ return (error);
+
+ dsl_dir_rele(dd, FTAG);
+
+ return (error);
+}
+
+static int
+zvol_set_snapdev_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
+{
+ zvol_set_snapdev_arg_t *zsda = arg;
+ char dsname[MAXNAMELEN];
+ zvol_task_t *task;
+
+ dsl_dataset_name(ds, dsname);
+ dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_SNAPDEV),
+ zsda->zsda_source, sizeof (zsda->zsda_value), 1,
+ &zsda->zsda_value, zsda->zsda_tx);
+
+ task = zvol_task_alloc(ZVOL_ASYNC_SET_SNAPDEV, dsname,
+ NULL, zsda->zsda_value);
+ if (task == NULL)
+ return (0);
+
+ (void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb,
+ task, TQ_SLEEP);
+ return (0);
+}
+
+/*
+ * Traverse all child snapshot datasets and apply snapdev appropriately.
+ */
+static void
+zvol_set_snapdev_sync(void *arg, dmu_tx_t *tx)
+{
+ zvol_set_snapdev_arg_t *zsda = arg;
+ dsl_pool_t *dp = dmu_tx_pool(tx);
+ dsl_dir_t *dd;
+
+ VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL));
+ zsda->zsda_tx = tx;
+
+ dmu_objset_find_dp(dp, dd->dd_object, zvol_set_snapdev_sync_cb,
+ zsda, DS_FIND_CHILDREN);
+
+ dsl_dir_rele(dd, FTAG);
+}
+
+int
+zvol_set_snapdev(const char *ddname, zprop_source_t source, uint64_t snapdev)
+{
+ zvol_set_snapdev_arg_t zsda;
+
+ zsda.zsda_name = ddname;
+ zsda.zsda_source = source;
+ zsda.zsda_value = snapdev;
+
+ return (dsl_sync_task(ddname, zvol_set_snapdev_check,
+ zvol_set_snapdev_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE));
+}
+
+void
+zvol_create_minors(spa_t *spa, const char *name, boolean_t async)
+{
+ zvol_task_t *task;
+ taskqid_t id;
+
+ task = zvol_task_alloc(ZVOL_ASYNC_CREATE_MINORS, name, NULL, ~0ULL);
+ if (task == NULL)
+ return;
+
+ id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
+ if ((async == B_FALSE) && (id != 0))
+ taskq_wait_id(spa->spa_zvol_taskq, id);
+}
+
+void
+zvol_remove_minors(spa_t *spa, const char *name, boolean_t async)
+{
+ zvol_task_t *task;
+ taskqid_t id;
+
+ task = zvol_task_alloc(ZVOL_ASYNC_REMOVE_MINORS, name, NULL, ~0ULL);
+ if (task == NULL)
+ return;
+
+ id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
+ if ((async == B_FALSE) && (id != 0))
+ taskq_wait_id(spa->spa_zvol_taskq, id);
+}
+
+void
+zvol_rename_minors(spa_t *spa, const char *name1, const char *name2,
+ boolean_t async)
+{
+ zvol_task_t *task;
+ taskqid_t id;
+
+ task = zvol_task_alloc(ZVOL_ASYNC_RENAME_MINORS, name1, name2, ~0ULL);
+ if (task == NULL)
+ return;
+
+ id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
+ if ((async == B_FALSE) && (id != 0))
+ taskq_wait_id(spa->spa_zvol_taskq, id);
+}
+
+int
+zvol_init(void)
+{
+ int error;
+
+ list_create(&zvol_state_list, sizeof (zvol_state_t),
+ offsetof(zvol_state_t, zv_next));
+ mutex_init(&zvol_state_lock, NULL, MUTEX_DEFAULT, NULL);
+
+ error = register_blkdev(zvol_major, ZVOL_DRIVER);
+ if (error) {
+ printk(KERN_INFO "ZFS: register_blkdev() failed %d\n", error);
+ goto out;
+ }
+
+ blk_register_region(MKDEV(zvol_major, 0), 1UL << MINORBITS,
+ THIS_MODULE, zvol_probe, NULL, NULL);
+
+ return (0);
+
+out:
+ mutex_destroy(&zvol_state_lock);
+ list_destroy(&zvol_state_list);
+
+ return (SET_ERROR(error));
+}
+
+void
+zvol_fini(void)
+{
+ zvol_remove_minors_impl(NULL);
+
+ blk_unregister_region(MKDEV(zvol_major, 0), 1UL << MINORBITS);
+ unregister_blkdev(zvol_major, ZVOL_DRIVER);
+
+ list_destroy(&zvol_state_list);
+ mutex_destroy(&zvol_state_lock);
+}
+
+module_param(zvol_inhibit_dev, uint, 0644);
+MODULE_PARM_DESC(zvol_inhibit_dev, "Do not create zvol device nodes");
+
+module_param(zvol_major, uint, 0444);
+MODULE_PARM_DESC(zvol_major, "Major number for zvol device");
+
+module_param(zvol_max_discard_blocks, ulong, 0444);
+MODULE_PARM_DESC(zvol_max_discard_blocks, "Max number of blocks to discard");
+
+module_param(zvol_prefetch_bytes, uint, 0644);
+MODULE_PARM_DESC(zvol_prefetch_bytes, "Prefetch N bytes at zvol start+end");
projects / mirror_ubuntu-artful-kernel.git / blobdiff