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Early versions of ZFS coordinated the creation and destruction of device minors from userspace. This was inherently racy and in late 2009 these ioctl()s were removed leaving everything up to the kernel. This significantly simplified the code. However, we never picked up these changes in ZoL since we'd already significantly adjusted this code for Linux. This patch aims to rectify that by finally removing ZFC_IOC_*_MINOR ioctl()s and moving all the functionality down in to the kernel. Since this cleanup will change the kernel/user ABI it's being done in the same tag as the previous libzfs_core ABI changes. This will minimize, but not eliminate, the disruption to end users. Once merged ZoL, Illumos, and FreeBSD will basically be back in sync in regards to handling ZVOLs in the common code. While each platform must have its own custom zvol.c implemenation the interfaces provided are consistent. NOTES: 1) This patch introduces one subtle change in behavior which could not be easily avoided. Prior to this change callers of 'zfs create -V ...' were guaranteed that upon exit the /dev/zvol/ block device link would be created or an error returned. That's no longer the case. The utilities will no longer block waiting for the symlink to be created. Callers are now responsible for blocking, this is why a 'udev_wait' call was added to the 'label' function in scripts/common.sh. 2) The read-only behavior of a ZVOL now solely depends on if the ZVOL_RDONLY bit is set in zv->zv_flags. The redundant policy setting in the gendisk structure was removed. This both simplifies the code and allows us to safely leverage set_disk_ro() to issue a KOBJ_CHANGE uevent. See the comment in the code for futher details on this. 3) Because __zvol_create_minor() and zvol_alloc() may now be called in a sync task they must use KM_PUSHPAGE. References: illumos/illumos-gate@681d9761e8 Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Tim Chase <tim@chase2k.com> Closes #1969
55 lines
1.8 KiB
C
55 lines
1.8 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
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*/
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#ifndef _SYS_ZVOL_H
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#define _SYS_ZVOL_H
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#include <sys/zfs_context.h>
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#define ZVOL_OBJ 1ULL
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#define ZVOL_ZAP_OBJ 2ULL
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#ifdef _KERNEL
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extern int zvol_check_volsize(uint64_t volsize, uint64_t blocksize);
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extern int zvol_check_volblocksize(uint64_t volblocksize);
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extern int zvol_get_stats(objset_t *os, nvlist_t *nv);
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extern boolean_t zvol_is_zvol(const char *);
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extern void zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx);
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extern int zvol_create_minor(const char *name);
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extern int zvol_create_minors(const char *name);
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extern int zvol_remove_minor(const char *name);
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extern void zvol_remove_minors(const char *name);
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extern void zvol_rename_minors(const char *oldname, const char *newname);
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extern int zvol_set_volsize(const char *, uint64_t);
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extern int zvol_set_volblocksize(const char *, uint64_t);
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extern int zvol_set_snapdev(const char *, uint64_t);
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extern int zvol_init(void);
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extern void zvol_fini(void);
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#endif /* _KERNEL */
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#endif /* _SYS_ZVOL_H */
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