xref: /netbsd-src/external/cddl/osnet/dist/uts/common/fs/zfs/sys/dmu_impl.h (revision 3227e6cf668bd374971740bd6660f43cee4417ac)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 /*
26  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
27  * Copyright (c) 2012, Martin Matuska <mm@FreeBSD.org>. All rights reserved.
28  * Copyright (c) 2013, 2015 by Delphix. All rights reserved.
29  */
30 
31 #ifndef _SYS_DMU_IMPL_H
32 #define	_SYS_DMU_IMPL_H
33 
34 #include <sys/txg_impl.h>
35 #include <sys/zio.h>
36 #include <sys/dnode.h>
37 #include <sys/kstat.h>
38 #include <sys/zfs_context.h>
39 #include <sys/zfs_ioctl.h>
40 
41 #ifdef	__cplusplus
42 extern "C" {
43 #endif
44 
45 /*
46  * This is the locking strategy for the DMU.  Numbers in parenthesis are
47  * cases that use that lock order, referenced below:
48  *
49  * ARC is self-contained
50  * bplist is self-contained
51  * refcount is self-contained
52  * txg is self-contained (hopefully!)
53  * zst_lock
54  * zf_rwlock
55  *
56  * XXX try to improve evicting path?
57  *
58  * dp_config_rwlock > os_obj_lock > dn_struct_rwlock >
59  * 	dn_dbufs_mtx > hash_mutexes > db_mtx > dd_lock > leafs
60  *
61  * dp_config_rwlock
62  *    must be held before: everything
63  *    protects dd namespace changes
64  *    protects property changes globally
65  *    held from:
66  *    	dsl_dir_open/r:
67  *    	dsl_dir_create_sync/w:
68  *    	dsl_dir_sync_destroy/w:
69  *    	dsl_dir_rename_sync/w:
70  *    	dsl_prop_changed_notify/r:
71  *
72  * os_obj_lock
73  *   must be held before:
74  *   	everything except dp_config_rwlock
75  *   protects os_obj_next
76  *   held from:
77  *   	dmu_object_alloc: dn_dbufs_mtx, db_mtx, hash_mutexes, dn_struct_rwlock
78  *
79  * dn_struct_rwlock
80  *   must be held before:
81  *   	everything except dp_config_rwlock and os_obj_lock
82  *   protects structure of dnode (eg. nlevels)
83  *   	db_blkptr can change when syncing out change to nlevels
84  *   	dn_maxblkid
85  *   	dn_nlevels
86  *   	dn_*blksz*
87  *   	phys nlevels, maxblkid, physical blkptr_t's (?)
88  *   held from:
89  *   	callers of dbuf_read_impl, dbuf_hold[_impl], dbuf_prefetch
90  *   	dmu_object_info_from_dnode: dn_dirty_mtx (dn_datablksz)
91  *   	dmu_tx_count_free:
92  *   	dbuf_read_impl: db_mtx, dmu_zfetch()
93  *   	dmu_zfetch: zf_rwlock/r, zst_lock, dbuf_prefetch()
94  *   	dbuf_new_size: db_mtx
95  *   	dbuf_dirty: db_mtx
96  *	dbuf_findbp: (callers, phys? - the real need)
97  *	dbuf_create: dn_dbufs_mtx, hash_mutexes, db_mtx (phys?)
98  *	dbuf_prefetch: dn_dirty_mtx, hash_mutexes, db_mtx, dn_dbufs_mtx
99  *	dbuf_hold_impl: hash_mutexes, db_mtx, dn_dbufs_mtx, dbuf_findbp()
100  *	dnode_sync/w (increase_indirection): db_mtx (phys)
101  *	dnode_set_blksz/w: dn_dbufs_mtx (dn_*blksz*)
102  *	dnode_new_blkid/w: (dn_maxblkid)
103  *	dnode_free_range/w: dn_dirty_mtx (dn_maxblkid)
104  *	dnode_next_offset: (phys)
105  *
106  * dn_dbufs_mtx
107  *    must be held before:
108  *    	db_mtx, hash_mutexes
109  *    protects:
110  *    	dn_dbufs
111  *    	dn_evicted
112  *    held from:
113  *    	dmu_evict_user: db_mtx (dn_dbufs)
114  *    	dbuf_free_range: db_mtx (dn_dbufs)
115  *    	dbuf_remove_ref: db_mtx, callees:
116  *    		dbuf_hash_remove: hash_mutexes, db_mtx
117  *    	dbuf_create: hash_mutexes, db_mtx (dn_dbufs)
118  *    	dnode_set_blksz: (dn_dbufs)
119  *
120  * hash_mutexes (global)
121  *   must be held before:
122  *   	db_mtx
123  *   protects dbuf_hash_table (global) and db_hash_next
124  *   held from:
125  *   	dbuf_find: db_mtx
126  *   	dbuf_hash_insert: db_mtx
127  *   	dbuf_hash_remove: db_mtx
128  *
129  * db_mtx (meta-leaf)
130  *   must be held before:
131  *   	dn_mtx, dn_dirty_mtx, dd_lock (leaf mutexes)
132  *   protects:
133  *   	db_state
134  * 	db_holds
135  * 	db_buf
136  * 	db_changed
137  * 	db_data_pending
138  * 	db_dirtied
139  * 	db_link
140  * 	db_dirty_node (??)
141  * 	db_dirtycnt
142  * 	db_d.*
143  * 	db.*
144  *   held from:
145  * 	dbuf_dirty: dn_mtx, dn_dirty_mtx
146  * 	dbuf_dirty->dsl_dir_willuse_space: dd_lock
147  * 	dbuf_dirty->dbuf_new_block->dsl_dataset_block_freeable: dd_lock
148  * 	dbuf_undirty: dn_dirty_mtx (db_d)
149  * 	dbuf_write_done: dn_dirty_mtx (db_state)
150  * 	dbuf_*
151  * 	dmu_buf_update_user: none (db_d)
152  * 	dmu_evict_user: none (db_d) (maybe can eliminate)
153  *   	dbuf_find: none (db_holds)
154  *   	dbuf_hash_insert: none (db_holds)
155  *   	dmu_buf_read_array_impl: none (db_state, db_changed)
156  *   	dmu_sync: none (db_dirty_node, db_d)
157  *   	dnode_reallocate: none (db)
158  *
159  * dn_mtx (leaf)
160  *   protects:
161  *   	dn_dirty_dbufs
162  *   	dn_ranges
163  *   	phys accounting
164  * 	dn_allocated_txg
165  * 	dn_free_txg
166  * 	dn_assigned_txg
167  * 	dd_assigned_tx
168  * 	dn_notxholds
169  * 	dn_dirtyctx
170  * 	dn_dirtyctx_firstset
171  * 	(dn_phys copy fields?)
172  * 	(dn_phys contents?)
173  *   held from:
174  *   	dnode_*
175  *   	dbuf_dirty: none
176  *   	dbuf_sync: none (phys accounting)
177  *   	dbuf_undirty: none (dn_ranges, dn_dirty_dbufs)
178  *   	dbuf_write_done: none (phys accounting)
179  *   	dmu_object_info_from_dnode: none (accounting)
180  *   	dmu_tx_commit: none
181  *   	dmu_tx_hold_object_impl: none
182  *   	dmu_tx_try_assign: dn_notxholds(cv)
183  *   	dmu_tx_unassign: none
184  *
185  * dd_lock
186  *    must be held before:
187  *      ds_lock
188  *      ancestors' dd_lock
189  *    protects:
190  *    	dd_prop_cbs
191  *    	dd_sync_*
192  *    	dd_used_bytes
193  *    	dd_tempreserved
194  *    	dd_space_towrite
195  *    	dd_myname
196  *    	dd_phys accounting?
197  *    held from:
198  *    	dsl_dir_*
199  *    	dsl_prop_changed_notify: none (dd_prop_cbs)
200  *    	dsl_prop_register: none (dd_prop_cbs)
201  *    	dsl_prop_unregister: none (dd_prop_cbs)
202  *    	dsl_dataset_block_freeable: none (dd_sync_*)
203  *
204  * os_lock (leaf)
205  *   protects:
206  *   	os_dirty_dnodes
207  *   	os_free_dnodes
208  *   	os_dnodes
209  *   	os_downgraded_dbufs
210  *   	dn_dirtyblksz
211  *   	dn_dirty_link
212  *   held from:
213  *   	dnode_create: none (os_dnodes)
214  *   	dnode_destroy: none (os_dnodes)
215  *   	dnode_setdirty: none (dn_dirtyblksz, os_*_dnodes)
216  *   	dnode_free: none (dn_dirtyblksz, os_*_dnodes)
217  *
218  * ds_lock
219  *    protects:
220  *    	ds_objset
221  *    	ds_open_refcount
222  *    	ds_snapname
223  *    	ds_phys accounting
224  *	ds_phys userrefs zapobj
225  *	ds_reserved
226  *    held from:
227  *    	dsl_dataset_*
228  *
229  * dr_mtx (leaf)
230  *    protects:
231  *	dr_children
232  *    held from:
233  *	dbuf_dirty
234  *	dbuf_undirty
235  *	dbuf_sync_indirect
236  *	dnode_new_blkid
237  */
238 
239 struct objset;
240 struct dmu_pool;
241 
242 typedef struct dmu_xuio {
243 	int next;
244 	int cnt;
245 	struct arc_buf **bufs;
246 	iovec_t *iovp;
247 } dmu_xuio_t;
248 
249 typedef struct xuio_stats {
250 	/* loaned yet not returned arc_buf */
251 	kstat_named_t xuiostat_onloan_rbuf;
252 	kstat_named_t xuiostat_onloan_wbuf;
253 	/* whether a copy is made when loaning out a read buffer */
254 	kstat_named_t xuiostat_rbuf_copied;
255 	kstat_named_t xuiostat_rbuf_nocopy;
256 	/* whether a copy is made when assigning a write buffer */
257 	kstat_named_t xuiostat_wbuf_copied;
258 	kstat_named_t xuiostat_wbuf_nocopy;
259 } xuio_stats_t;
260 
261 static xuio_stats_t xuio_stats = {
262 	{ "onloan_read_buf",	KSTAT_DATA_UINT64 },
263 	{ "onloan_write_buf",	KSTAT_DATA_UINT64 },
264 	{ "read_buf_copied",	KSTAT_DATA_UINT64 },
265 	{ "read_buf_nocopy",	KSTAT_DATA_UINT64 },
266 	{ "write_buf_copied",	KSTAT_DATA_UINT64 },
267 	{ "write_buf_nocopy",	KSTAT_DATA_UINT64 }
268 };
269 
270 #define	XUIOSTAT_INCR(stat, val)	\
271 	atomic_add_64(&xuio_stats.stat.value.ui64, (val))
272 #define	XUIOSTAT_BUMP(stat)	XUIOSTAT_INCR(stat, 1)
273 
274 /*
275  * The list of data whose inclusion in a send stream can be pending from
276  * one call to backup_cb to another.  Multiple calls to dump_free() and
277  * dump_freeobjects() can be aggregated into a single DRR_FREE or
278  * DRR_FREEOBJECTS replay record.
279  */
280 typedef enum {
281 	PENDING_NONE,
282 	PENDING_FREE,
283 	PENDING_FREEOBJECTS
284 } dmu_pendop_t;
285 
286 typedef struct dmu_sendarg {
287 	list_node_t dsa_link;
288 	dmu_replay_record_t *dsa_drr;
289 	kthread_t *dsa_td;
290 	struct file *dsa_fp;
291 	int dsa_outfd;
292 	struct proc *dsa_proc;
293 	offset_t *dsa_off;
294 	objset_t *dsa_os;
295 	zio_cksum_t dsa_zc;
296 	uint64_t dsa_toguid;
297 	int dsa_err;
298 	dmu_pendop_t dsa_pending_op;
299 	uint64_t dsa_featureflags;
300 	uint64_t dsa_last_data_object;
301 	uint64_t dsa_last_data_offset;
302 	uint64_t dsa_resume_object;
303 	uint64_t dsa_resume_offset;
304 	boolean_t dsa_sent_begin;
305 	boolean_t dsa_sent_end;
306 } dmu_sendarg_t;
307 
308 void dmu_object_zapify(objset_t *, uint64_t, dmu_object_type_t, dmu_tx_t *);
309 void dmu_object_free_zapified(objset_t *, uint64_t, dmu_tx_t *);
310 int dmu_buf_hold_noread(objset_t *, uint64_t, uint64_t,
311     void *, dmu_buf_t **);
312 
313 #ifdef	__cplusplus
314 }
315 #endif
316 
317 #endif	/* _SYS_DMU_IMPL_H */
318