xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/dmu_impl.h (revision b49b27dcb66b2c7f4a23f7bc158e2dde5cd79030)
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  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
25  */
26 
27 #ifndef _SYS_DMU_IMPL_H
28 #define	_SYS_DMU_IMPL_H
29 
30 #include <sys/txg_impl.h>
31 #include <sys/zio.h>
32 #include <sys/dnode.h>
33 #include <sys/zfs_context.h>
34 #include <sys/zfs_ioctl.h>
35 
36 #ifdef	__cplusplus
37 extern "C" {
38 #endif
39 
40 /*
41  * This is the locking strategy for the DMU.  Numbers in parenthesis are
42  * cases that use that lock order, referenced below:
43  *
44  * ARC is self-contained
45  * bplist is self-contained
46  * refcount is self-contained
47  * txg is self-contained (hopefully!)
48  * zst_lock
49  * zf_rwlock
50  *
51  * XXX try to improve evicting path?
52  *
53  * dp_config_rwlock > os_obj_lock > dn_struct_rwlock >
54  * 	dn_dbufs_mtx > hash_mutexes > db_mtx > dd_lock > leafs
55  *
56  * dp_config_rwlock
57  *    must be held before: everything
58  *    protects dd namespace changes
59  *    protects property changes globally
60  *    held from:
61  *    	dsl_dir_open/r:
62  *    	dsl_dir_create_sync/w:
63  *    	dsl_dir_sync_destroy/w:
64  *    	dsl_dir_rename_sync/w:
65  *    	dsl_prop_changed_notify/r:
66  *
67  * os_obj_lock
68  *   must be held before:
69  *   	everything except dp_config_rwlock
70  *   protects os_obj_next
71  *   held from:
72  *   	dmu_object_alloc: dn_dbufs_mtx, db_mtx, hash_mutexes, dn_struct_rwlock
73  *
74  * dn_struct_rwlock
75  *   must be held before:
76  *   	everything except dp_config_rwlock and os_obj_lock
77  *   protects structure of dnode (eg. nlevels)
78  *   	db_blkptr can change when syncing out change to nlevels
79  *   	dn_maxblkid
80  *   	dn_nlevels
81  *   	dn_*blksz*
82  *   	phys nlevels, maxblkid, physical blkptr_t's (?)
83  *   held from:
84  *   	callers of dbuf_read_impl, dbuf_hold[_impl], dbuf_prefetch
85  *   	dmu_object_info_from_dnode: dn_dirty_mtx (dn_datablksz)
86  *   	dmu_tx_count_free:
87  *   	dbuf_read_impl: db_mtx, dmu_zfetch()
88  *   	dmu_zfetch: zf_rwlock/r, zst_lock, dbuf_prefetch()
89  *   	dbuf_new_size: db_mtx
90  *   	dbuf_dirty: db_mtx
91  *	dbuf_findbp: (callers, phys? - the real need)
92  *	dbuf_create: dn_dbufs_mtx, hash_mutexes, db_mtx (phys?)
93  *	dbuf_prefetch: dn_dirty_mtx, hash_mutexes, db_mtx, dn_dbufs_mtx
94  *	dbuf_hold_impl: hash_mutexes, db_mtx, dn_dbufs_mtx, dbuf_findbp()
95  *	dnode_sync/w (increase_indirection): db_mtx (phys)
96  *	dnode_set_blksz/w: dn_dbufs_mtx (dn_*blksz*)
97  *	dnode_new_blkid/w: (dn_maxblkid)
98  *	dnode_free_range/w: dn_dirty_mtx (dn_maxblkid)
99  *	dnode_next_offset: (phys)
100  *
101  * dn_dbufs_mtx
102  *    must be held before:
103  *    	db_mtx, hash_mutexes
104  *    protects:
105  *    	dn_dbufs
106  *    	dn_evicted
107  *    held from:
108  *    	dmu_evict_user: db_mtx (dn_dbufs)
109  *    	dbuf_free_range: db_mtx (dn_dbufs)
110  *    	dbuf_remove_ref: db_mtx, callees:
111  *    		dbuf_hash_remove: hash_mutexes, db_mtx
112  *    	dbuf_create: hash_mutexes, db_mtx (dn_dbufs)
113  *    	dnode_set_blksz: (dn_dbufs)
114  *
115  * hash_mutexes (global)
116  *   must be held before:
117  *   	db_mtx
118  *   protects dbuf_hash_table (global) and db_hash_next
119  *   held from:
120  *   	dbuf_find: db_mtx
121  *   	dbuf_hash_insert: db_mtx
122  *   	dbuf_hash_remove: db_mtx
123  *
124  * db_mtx (meta-leaf)
125  *   must be held before:
126  *   	dn_mtx, dn_dirty_mtx, dd_lock (leaf mutexes)
127  *   protects:
128  *   	db_state
129  * 	db_holds
130  * 	db_buf
131  * 	db_changed
132  * 	db_data_pending
133  * 	db_dirtied
134  * 	db_link
135  * 	db_dirty_node (??)
136  * 	db_dirtycnt
137  * 	db_d.*
138  * 	db.*
139  *   held from:
140  * 	dbuf_dirty: dn_mtx, dn_dirty_mtx
141  * 	dbuf_dirty->dsl_dir_willuse_space: dd_lock
142  * 	dbuf_dirty->dbuf_new_block->dsl_dataset_block_freeable: dd_lock
143  * 	dbuf_undirty: dn_dirty_mtx (db_d)
144  * 	dbuf_write_done: dn_dirty_mtx (db_state)
145  * 	dbuf_*
146  * 	dmu_buf_update_user: none (db_d)
147  * 	dmu_evict_user: none (db_d) (maybe can eliminate)
148  *   	dbuf_find: none (db_holds)
149  *   	dbuf_hash_insert: none (db_holds)
150  *   	dmu_buf_read_array_impl: none (db_state, db_changed)
151  *   	dmu_sync: none (db_dirty_node, db_d)
152  *   	dnode_reallocate: none (db)
153  *
154  * dn_mtx (leaf)
155  *   protects:
156  *   	dn_dirty_dbufs
157  *   	dn_ranges
158  *   	phys accounting
159  * 	dn_allocated_txg
160  * 	dn_free_txg
161  * 	dn_assigned_txg
162  * 	dd_assigned_tx
163  * 	dn_notxholds
164  * 	dn_dirtyctx
165  * 	dn_dirtyctx_firstset
166  * 	(dn_phys copy fields?)
167  * 	(dn_phys contents?)
168  *   held from:
169  *   	dnode_*
170  *   	dbuf_dirty: none
171  *   	dbuf_sync: none (phys accounting)
172  *   	dbuf_undirty: none (dn_ranges, dn_dirty_dbufs)
173  *   	dbuf_write_done: none (phys accounting)
174  *   	dmu_object_info_from_dnode: none (accounting)
175  *   	dmu_tx_commit: none
176  *   	dmu_tx_hold_object_impl: none
177  *   	dmu_tx_try_assign: dn_notxholds(cv)
178  *   	dmu_tx_unassign: none
179  *
180  * dd_lock
181  *    must be held before:
182  *      ds_lock
183  *      ancestors' dd_lock
184  *    protects:
185  *    	dd_prop_cbs
186  *    	dd_sync_*
187  *    	dd_used_bytes
188  *    	dd_tempreserved
189  *    	dd_space_towrite
190  *    	dd_myname
191  *    	dd_phys accounting?
192  *    held from:
193  *    	dsl_dir_*
194  *    	dsl_prop_changed_notify: none (dd_prop_cbs)
195  *    	dsl_prop_register: none (dd_prop_cbs)
196  *    	dsl_prop_unregister: none (dd_prop_cbs)
197  *    	dsl_dataset_block_freeable: none (dd_sync_*)
198  *
199  * os_lock (leaf)
200  *   protects:
201  *   	os_dirty_dnodes
202  *   	os_free_dnodes
203  *   	os_dnodes
204  *   	os_downgraded_dbufs
205  *   	dn_dirtyblksz
206  *   	dn_dirty_link
207  *   held from:
208  *   	dnode_create: none (os_dnodes)
209  *   	dnode_destroy: none (os_dnodes)
210  *   	dnode_setdirty: none (dn_dirtyblksz, os_*_dnodes)
211  *   	dnode_free: none (dn_dirtyblksz, os_*_dnodes)
212  *
213  * ds_lock
214  *    protects:
215  *    	ds_objset
216  *    	ds_open_refcount
217  *    	ds_snapname
218  *    	ds_phys accounting
219  *	ds_phys userrefs zapobj
220  *	ds_reserved
221  *    held from:
222  *    	dsl_dataset_*
223  *
224  * dr_mtx (leaf)
225  *    protects:
226  *	dr_children
227  *    held from:
228  *	dbuf_dirty
229  *	dbuf_undirty
230  *	dbuf_sync_indirect
231  *	dnode_new_blkid
232  */
233 
234 struct objset;
235 struct dmu_pool;
236 
237 typedef struct dmu_xuio {
238 	int next;
239 	int cnt;
240 	struct arc_buf **bufs;
241 	iovec_t *iovp;
242 } dmu_xuio_t;
243 
244 typedef struct xuio_stats {
245 	/* loaned yet not returned arc_buf */
246 	kstat_named_t xuiostat_onloan_rbuf;
247 	kstat_named_t xuiostat_onloan_wbuf;
248 	/* whether a copy is made when loaning out a read buffer */
249 	kstat_named_t xuiostat_rbuf_copied;
250 	kstat_named_t xuiostat_rbuf_nocopy;
251 	/* whether a copy is made when assigning a write buffer */
252 	kstat_named_t xuiostat_wbuf_copied;
253 	kstat_named_t xuiostat_wbuf_nocopy;
254 } xuio_stats_t;
255 
256 static xuio_stats_t xuio_stats = {
257 	{ "onloan_read_buf",	KSTAT_DATA_UINT64 },
258 	{ "onloan_write_buf",	KSTAT_DATA_UINT64 },
259 	{ "read_buf_copied",	KSTAT_DATA_UINT64 },
260 	{ "read_buf_nocopy",	KSTAT_DATA_UINT64 },
261 	{ "write_buf_copied",	KSTAT_DATA_UINT64 },
262 	{ "write_buf_nocopy",	KSTAT_DATA_UINT64 }
263 };
264 
265 #define	XUIOSTAT_INCR(stat, val)	\
266 	atomic_add_64(&xuio_stats.stat.value.ui64, (val))
267 #define	XUIOSTAT_BUMP(stat)	XUIOSTAT_INCR(stat, 1)
268 
269 /*
270  * The list of data whose inclusion in a send stream can be pending from
271  * one call to backup_cb to another.  Multiple calls to dump_free() and
272  * dump_freeobjects() can be aggregated into a single DRR_FREE or
273  * DRR_FREEOBJECTS replay record.
274  */
275 typedef enum {
276 	PENDING_NONE,
277 	PENDING_FREE,
278 	PENDING_FREEOBJECTS
279 } dmu_pendop_t;
280 
281 typedef struct dmu_sendarg {
282 	list_node_t dsa_link;
283 	dmu_replay_record_t *dsa_drr;
284 	vnode_t *dsa_vp;
285 	int dsa_outfd;
286 	struct proc *dsa_proc;
287 	offset_t *dsa_off;
288 	objset_t *dsa_os;
289 	zio_cksum_t dsa_zc;
290 	uint64_t dsa_toguid;
291 	int dsa_err;
292 	dmu_pendop_t dsa_pending_op;
293 } dmu_sendarg_t;
294 
295 
296 #ifdef	__cplusplus
297 }
298 #endif
299 
300 #endif	/* _SYS_DMU_IMPL_H */
301