OpenZFS restructuring - zvol

Refactor the zvol in to platform dependent and independent bits.

Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9295

include/sys/Makefile.am

@@ -125,7 +125,8 @@ COMMON_H = \
 KERNEL_H = \
 	$(top_srcdir)/include/sys/zfs_ioctl.h \
 	$(top_srcdir)/include/sys/zfs_onexit.h \
-	$(top_srcdir)/include/sys/zvol.h
+	$(top_srcdir)/include/sys/zvol.h \
+	$(top_srcdir)/include/sys/zvol_impl.h
 
 USER_H =
 

include/sys/dmu.h

@@ -337,7 +337,7 @@ int dsl_destroy_snapshots_nvl(struct nvlist *snaps, boolean_t defer,
     struct nvlist *errlist);
 int dmu_objset_snapshot_one(const char *fsname, const char *snapname);
 int dmu_objset_snapshot_tmp(const char *, const char *, int);
-int dmu_objset_find(char *name, int func(const char *, void *), void *arg,
+int dmu_objset_find(const char *name, int func(const char *, void *), void *arg,
     int flags);
 void dmu_objset_byteswap(void *buf, size_t size);
 int dsl_dataset_rename_snapshot(const char *fsname,

include/sys/zvol.h

@@ -41,7 +41,8 @@ extern void zvol_rename_minors(spa_t *spa, const char *oldname,
     const char *newname, boolean_t async);
 
 #ifdef _KERNEL
-typedef struct zvol_state zvol_state_t;
+struct zvol_state;
+typedef struct zvol_state zvol_state_handle_t;
 
 extern int zvol_check_volsize(uint64_t volsize, uint64_t blocksize);
 extern int zvol_check_volblocksize(const char *name, uint64_t volblocksize);
@@ -52,11 +53,13 @@ extern int zvol_set_volsize(const char *, uint64_t);
 extern int zvol_set_volblocksize(const char *, uint64_t);
 extern int zvol_set_snapdev(const char *, zprop_source_t, uint64_t);
 extern int zvol_set_volmode(const char *, zprop_source_t, uint64_t);
-extern zvol_state_t *zvol_suspend(const char *);
-extern int zvol_resume(zvol_state_t *);
-extern void *zvol_tag(zvol_state_t *);
+extern zvol_state_handle_t *zvol_suspend(const char *);
+extern int zvol_resume(zvol_state_handle_t *);
+extern void *zvol_tag(zvol_state_handle_t *);
 
 extern int zvol_init(void);
 extern void zvol_fini(void);
+extern int zvol_busy(void);
+
 #endif /* _KERNEL */
 #endif /* _SYS_ZVOL_H */

include/sys/zvol_impl.h

@@ -0,0 +1,107 @@
+/*
+ * 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
+ */
+
+#ifndef	_SYS_ZVOL_IMPL_H
+#define	_SYS_ZVOL_IMPL_H
+
+#include <sys/zfs_context.h>
+
+#define	ZVOL_RDONLY	0x1
+/*
+ * Whether the zvol has been written to (as opposed to ZVOL_RDONLY, which
+ * specifies whether or not the zvol _can_ be written to)
+ */
+#define	ZVOL_WRITTEN_TO	0x2
+
+#define	ZVOL_DUMPIFIED	0x4
+
+#define	ZVOL_EXCL	0x8
+
+/*
+ * 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 */
+	rangelock_t		zv_rangelock;	/* for range locking */
+	dnode_t			*zv_dn;		/* dnode hold */
+	list_node_t		zv_next;	/* next zvol_state_t linkage */
+	uint64_t		zv_hash;	/* name hash */
+	struct hlist_node	zv_hlink;	/* hash link */
+	kmutex_t		zv_state_lock;	/* protects zvol_state_t */
+	atomic_t		zv_suspend_ref;	/* refcount for suspend */
+	krwlock_t		zv_suspend_lock;	/* suspend lock */
+	struct zvol_state_os	*zv_zso;	/* private platform state */
+} zvol_state_t;
+
+
+extern list_t zvol_state_list;
+extern krwlock_t zvol_state_lock;
+#define	ZVOL_HT_SIZE	1024
+extern struct hlist_head *zvol_htable;
+#define	ZVOL_HT_HEAD(hash)	(&zvol_htable[(hash) & (ZVOL_HT_SIZE-1)])
+extern zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE];
+
+extern unsigned int zvol_volmode;
+extern unsigned int zvol_inhibit_dev;
+
+/*
+ * platform independent functions exported to platform code
+ */
+zvol_state_t *zvol_find_by_name_hash(const char *name,
+    uint64_t hash, int mode);
+int zvol_first_open(zvol_state_t *zv, boolean_t readonly);
+uint64_t zvol_name_hash(const char *name);
+void zvol_remove_minors_impl(const char *name);
+void zvol_last_close(zvol_state_t *zv);
+void zvol_insert(zvol_state_t *zv);
+void zvol_log_truncate(zvol_state_t *zv, dmu_tx_t *tx, uint64_t off,
+    uint64_t len, boolean_t sync);
+void zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, uint64_t offset,
+    uint64_t size, int sync);
+int zvol_get_data(void *arg, lr_write_t *lr, char *buf, struct lwb *lwb,
+    zio_t *zio);
+int zvol_init_impl(void);
+void zvol_fini_impl(void);
+
+/*
+ * platform dependent functions exported to platform independent code
+ */
+typedef struct zvol_platform_ops {
+	void (*zv_free)(zvol_state_t *);
+	void (*zv_rename_minor)(zvol_state_t *, const char *);
+	int (*zv_create_minor)(const char *);
+	int (*zv_update_volsize)(zvol_state_t *, uint64_t);
+	boolean_t (*zv_is_zvol)(const char *);
+	void (*zv_clear_private)(zvol_state_t *);
+	void (*zv_set_disk_ro)(zvol_state_t *, int flags);
+	void (*zv_set_capacity)(zvol_state_t *, uint64_t capacity);
+} zvol_platform_ops_t;
+
+void zvol_register_ops(const zvol_platform_ops_t *ops);
+
+#endif

module/os/linux/zfs/Makefile.in

@@ -33,3 +33,4 @@ $(MODULE)-objs += ../os/linux/zfs/zpl_file.o
 $(MODULE)-objs += ../os/linux/zfs/zpl_inode.o
 $(MODULE)-objs += ../os/linux/zfs/zpl_super.o
 $(MODULE)-objs += ../os/linux/zfs/zpl_xattr.o
+$(MODULE)-objs += ../os/linux/zfs/zvol_os.o

module/zfs/dmu_objset.c

@@ -2856,7 +2856,7 @@ dmu_objset_find_impl(spa_t *spa, const char *name,
  * See comment above dmu_objset_find_impl().
  */
 int
-dmu_objset_find(char *name, int func(const char *, void *), void *arg,
+dmu_objset_find(const char *name, int func(const char *, void *), void *arg,
     int flags)
 {
 	spa_t *spa;

module/zfs/zfs_ioctl.c

@@ -4136,7 +4136,7 @@ static int
 zfs_ioc_rollback(const char *fsname, nvlist_t *innvl, nvlist_t *outnvl)
 {
 	zfsvfs_t *zfsvfs;
-	zvol_state_t *zv;
+	zvol_state_handle_t *zv;
 	char *target = NULL;
 	int error;
 
@@ -4861,7 +4861,7 @@ zfs_ioc_recv_impl(char *tofs, char *tosnap, char *origin, nvlist_t *recvprops,
 
 	if (error == 0) {
 		zfsvfs_t *zfsvfs = NULL;
-		zvol_state_t *zv = NULL;
+		zvol_state_handle_t *zv = NULL;
 
 		if (getzfsvfs(tofs, &zfsvfs) == 0) {
 			/* online recv */
@@ -7671,7 +7671,7 @@ _init(void)
 {
 	int error;
 
-	if ((error = -zvol_init()) != 0)
+	if ((error = zvol_init()) != 0)
 		return (error);
 
 	spa_init(FREAD | FWRITE);