xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/dmu_impl.h (revision 4870e0a7381ec2ec57437062574e6ddc3dd48d7f)
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) 2013, 2015 by Delphix. All rights reserved.
28  */
29 
30 #ifndef _SYS_DMU_IMPL_H
31 #define	_SYS_DMU_IMPL_H
32 
33 #include <sys/txg_impl.h>
34 #include <sys/zio.h>
35 #include <sys/dnode.h>
36 #include <sys/zfs_context.h>
37 #include <sys/zfs_ioctl.h>
38 
39 #ifdef	__cplusplus
40 extern "C" {
41 #endif
42 
43 /*
44  * This is the locking strategy for the DMU.  Numbers in parenthesis are
45  * cases that use that lock order, referenced below:
46  *
47  * ARC is self-contained
48  * bplist is self-contained
49  * refcount is self-contained
50  * txg is self-contained (hopefully!)
51  * zst_lock
52  * zf_rwlock
53  *
54  * XXX try to improve evicting path?
55  *
56  * dp_config_rwlock > os_obj_lock > dn_struct_rwlock >
57  * 	dn_dbufs_mtx > hash_mutexes > db_mtx > dd_lock > leafs
58  *
59  * dp_config_rwlock
60  *    must be held before: everything
61  *    protects dd namespace changes
62  *    protects property changes globally
63  *    held from:
64  *    	dsl_dir_open/r:
65  *    	dsl_dir_create_sync/w:
66  *    	dsl_dir_sync_destroy/w:
67  *    	dsl_dir_rename_sync/w:
68  *    	dsl_prop_changed_notify/r:
69  *
70  * os_obj_lock
71  *   must be held before:
72  *   	everything except dp_config_rwlock
73  *   protects os_obj_next
74  *   held from:
75  *   	dmu_object_alloc: dn_dbufs_mtx, db_mtx, hash_mutexes, dn_struct_rwlock
76  *
77  * dn_struct_rwlock
78  *   must be held before:
79  *   	everything except dp_config_rwlock and os_obj_lock
80  *   protects structure of dnode (eg. nlevels)
81  *   	db_blkptr can change when syncing out change to nlevels
82  *   	dn_maxblkid
83  *   	dn_nlevels
84  *   	dn_*blksz*
85  *   	phys nlevels, maxblkid, physical blkptr_t's (?)
86  *   held from:
87  *   	callers of dbuf_read_impl, dbuf_hold[_impl], dbuf_prefetch
88  *   	dmu_object_info_from_dnode: dn_dirty_mtx (dn_datablksz)
89  *   	dmu_tx_count_free:
90  *   	dbuf_read_impl: db_mtx, dmu_zfetch()
91  *   	dmu_zfetch: zf_rwlock/r, zst_lock, dbuf_prefetch()
92  *   	dbuf_new_size: db_mtx
93  *   	dbuf_dirty: db_mtx
94  *	dbuf_findbp: (callers, phys? - the real need)
95  *	dbuf_create: dn_dbufs_mtx, hash_mutexes, db_mtx (phys?)
96  *	dbuf_prefetch: dn_dirty_mtx, hash_mutexes, db_mtx, dn_dbufs_mtx
97  *	dbuf_hold_impl: hash_mutexes, db_mtx, dn_dbufs_mtx, dbuf_findbp()
98  *	dnode_sync/w (increase_indirection): db_mtx (phys)
99  *	dnode_set_blksz/w: dn_dbufs_mtx (dn_*blksz*)
100  *	dnode_new_blkid/w: (dn_maxblkid)
101  *	dnode_free_range/w: dn_dirty_mtx (dn_maxblkid)
102  *	dnode_next_offset: (phys)
103  *
104  * dn_dbufs_mtx
105  *    must be held before:
106  *    	db_mtx, hash_mutexes
107  *    protects:
108  *    	dn_dbufs
109  *    	dn_evicted
110  *    held from:
111  *    	dmu_evict_user: db_mtx (dn_dbufs)
112  *    	dbuf_free_range: db_mtx (dn_dbufs)
113  *    	dbuf_remove_ref: db_mtx, callees:
114  *    		dbuf_hash_remove: hash_mutexes, db_mtx
115  *    	dbuf_create: hash_mutexes, db_mtx (dn_dbufs)
116  *    	dnode_set_blksz: (dn_dbufs)
117  *
118  * hash_mutexes (global)
119  *   must be held before:
120  *   	db_mtx
121  *   protects dbuf_hash_table (global) and db_hash_next
122  *   held from:
123  *   	dbuf_find: db_mtx
124  *   	dbuf_hash_insert: db_mtx
125  *   	dbuf_hash_remove: db_mtx
126  *
127  * db_mtx (meta-leaf)
128  *   must be held before:
129  *   	dn_mtx, dn_dirty_mtx, dd_lock (leaf mutexes)
130  *   protects:
131  *   	db_state
132  * 	db_holds
133  * 	db_buf
134  * 	db_changed
135  * 	db_data_pending
136  * 	db_dirtied
137  * 	db_link
138  * 	db_dirty_node (??)
139  * 	db_dirtycnt
140  * 	db_d.*
141  * 	db.*
142  *   held from:
143  * 	dbuf_dirty: dn_mtx, dn_dirty_mtx
144  * 	dbuf_dirty->dsl_dir_willuse_space: dd_lock
145  * 	dbuf_dirty->dbuf_new_block->dsl_dataset_block_freeable: dd_lock
146  * 	dbuf_undirty: dn_dirty_mtx (db_d)
147  * 	dbuf_write_done: dn_dirty_mtx (db_state)
148  * 	dbuf_*
149  * 	dmu_buf_update_user: none (db_d)
150  * 	dmu_evict_user: none (db_d) (maybe can eliminate)
151  *   	dbuf_find: none (db_holds)
152  *   	dbuf_hash_insert: none (db_holds)
153  *   	dmu_buf_read_array_impl: none (db_state, db_changed)
154  *   	dmu_sync: none (db_dirty_node, db_d)
155  *   	dnode_reallocate: none (db)
156  *
157  * dn_mtx (leaf)
158  *   protects:
159  *   	dn_dirty_dbufs
160  *   	dn_ranges
161  *   	phys accounting
162  * 	dn_allocated_txg
163  * 	dn_free_txg
164  * 	dn_assigned_txg
165  * 	dd_assigned_tx
166  * 	dn_notxholds
167  * 	dn_dirtyctx
168  * 	dn_dirtyctx_firstset
169  * 	(dn_phys copy fields?)
170  * 	(dn_phys contents?)
171  *   held from:
172  *   	dnode_*
173  *   	dbuf_dirty: none
174  *   	dbuf_sync: none (phys accounting)
175  *   	dbuf_undirty: none (dn_ranges, dn_dirty_dbufs)
176  *   	dbuf_write_done: none (phys accounting)
177  *   	dmu_object_info_from_dnode: none (accounting)
178  *   	dmu_tx_commit: none
179  *   	dmu_tx_hold_object_impl: none
180  *   	dmu_tx_try_assign: dn_notxholds(cv)
181  *   	dmu_tx_unassign: none
182  *
183  * dd_lock
184  *    must be held before:
185  *      ds_lock
186  *      ancestors' dd_lock
187  *    protects:
188  *    	dd_prop_cbs
189  *    	dd_sync_*
190  *    	dd_used_bytes
191  *    	dd_tempreserved
192  *    	dd_space_towrite
193  *    	dd_myname
194  *    	dd_phys accounting?
195  *    held from:
196  *    	dsl_dir_*
197  *    	dsl_prop_changed_notify: none (dd_prop_cbs)
198  *    	dsl_prop_register: none (dd_prop_cbs)
199  *    	dsl_prop_unregister: none (dd_prop_cbs)
200  *    	dsl_dataset_block_freeable: none (dd_sync_*)
201  *
202  * os_lock (leaf)
203  *   protects:
204  *   	os_dirty_dnodes
205  *   	os_free_dnodes
206  *   	os_dnodes
207  *   	os_downgraded_dbufs
208  *   	dn_dirtyblksz
209  *   	dn_dirty_link
210  *   held from:
211  *   	dnode_create: none (os_dnodes)
212  *   	dnode_destroy: none (os_dnodes)
213  *   	dnode_setdirty: none (dn_dirtyblksz, os_*_dnodes)
214  *   	dnode_free: none (dn_dirtyblksz, os_*_dnodes)
215  *
216  * ds_lock
217  *    protects:
218  *    	ds_objset
219  *    	ds_open_refcount
220  *    	ds_snapname
221  *    	ds_phys accounting
222  *	ds_phys userrefs zapobj
223  *	ds_reserved
224  *    held from:
225  *    	dsl_dataset_*
226  *
227  * dr_mtx (leaf)
228  *    protects:
229  *	dr_children
230  *    held from:
231  *	dbuf_dirty
232  *	dbuf_undirty
233  *	dbuf_sync_indirect
234  *	dnode_new_blkid
235  */
236 
237 struct objset;
238 struct dmu_pool;
239 
240 typedef struct dmu_xuio {
241 	int next;
242 	int cnt;
243 	struct arc_buf **bufs;
244 	iovec_t *iovp;
245 } dmu_xuio_t;
246 
247 typedef struct xuio_stats {
248 	/* loaned yet not returned arc_buf */
249 	kstat_named_t xuiostat_onloan_rbuf;
250 	kstat_named_t xuiostat_onloan_wbuf;
251 	/* whether a copy is made when loaning out a read buffer */
252 	kstat_named_t xuiostat_rbuf_copied;
253 	kstat_named_t xuiostat_rbuf_nocopy;
254 	/* whether a copy is made when assigning a write buffer */
255 	kstat_named_t xuiostat_wbuf_copied;
256 	kstat_named_t xuiostat_wbuf_nocopy;
257 } xuio_stats_t;
258 
259 static xuio_stats_t xuio_stats = {
260 	{ "onloan_read_buf",	KSTAT_DATA_UINT64 },
261 	{ "onloan_write_buf",	KSTAT_DATA_UINT64 },
262 	{ "read_buf_copied",	KSTAT_DATA_UINT64 },
263 	{ "read_buf_nocopy",	KSTAT_DATA_UINT64 },
264 	{ "write_buf_copied",	KSTAT_DATA_UINT64 },
265 	{ "write_buf_nocopy",	KSTAT_DATA_UINT64 }
266 };
267 
268 #define	XUIOSTAT_INCR(stat, val)	\
269 	atomic_add_64(&xuio_stats.stat.value.ui64, (val))
270 #define	XUIOSTAT_BUMP(stat)	XUIOSTAT_INCR(stat, 1)
271 
272 /*
273  * The list of data whose inclusion in a send stream can be pending from
274  * one call to backup_cb to another.  Multiple calls to dump_free() and
275  * dump_freeobjects() can be aggregated into a single DRR_FREE or
276  * DRR_FREEOBJECTS replay record.
277  */
278 typedef enum {
279 	PENDING_NONE,
280 	PENDING_FREE,
281 	PENDING_FREEOBJECTS
282 } dmu_pendop_t;
283 
284 typedef struct dmu_sendarg {
285 	list_node_t dsa_link;
286 	dmu_replay_record_t *dsa_drr;
287 	vnode_t *dsa_vp;
288 	int dsa_outfd;
289 	struct proc *dsa_proc;
290 	offset_t *dsa_off;
291 	objset_t *dsa_os;
292 	zio_cksum_t dsa_zc;
293 	uint64_t dsa_toguid;
294 	int dsa_err;
295 	dmu_pendop_t dsa_pending_op;
296 	uint64_t dsa_featureflags;
297 	uint64_t dsa_last_data_object;
298 	uint64_t dsa_last_data_offset;
299 	uint64_t dsa_resume_object;
300 	uint64_t dsa_resume_offset;
301 } dmu_sendarg_t;
302 
303 void dmu_object_zapify(objset_t *, uint64_t, dmu_object_type_t, dmu_tx_t *);
304 void dmu_object_free_zapified(objset_t *, uint64_t, dmu_tx_t *);
305 int dmu_buf_hold_noread(objset_t *, uint64_t, uint64_t,
306     void *, dmu_buf_t **);
307 
308 #ifdef	__cplusplus
309 }
310 #endif
311 
312 #endif	/* _SYS_DMU_IMPL_H */
313