1 /*
2  * Copyright (c) 2020 iXsystems, Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include <sys/types.h>
32 #include <sys/param.h>
33 #include <sys/dmu.h>
34 #include <sys/dmu_impl.h>
35 #include <sys/dmu_tx.h>
36 #include <sys/dbuf.h>
37 #include <sys/dnode.h>
38 #include <sys/zfs_context.h>
39 #include <sys/dmu_objset.h>
40 #include <sys/dmu_traverse.h>
41 #include <sys/dsl_dataset.h>
42 #include <sys/dsl_dir.h>
43 #include <sys/dsl_pool.h>
44 #include <sys/dsl_synctask.h>
45 #include <sys/dsl_prop.h>
46 #include <sys/dmu_zfetch.h>
47 #include <sys/zfs_ioctl.h>
48 #include <sys/zap.h>
49 #include <sys/zio_checksum.h>
50 #include <sys/zio_compress.h>
51 #include <sys/sa.h>
52 #include <sys/zfeature.h>
53 #include <sys/abd.h>
54 #include <sys/zfs_rlock.h>
55 #include <sys/racct.h>
56 #include <sys/vm.h>
57 #include <sys/zfs_znode.h>
58 #include <sys/zfs_vnops.h>
59 
60 #include <sys/ccompat.h>
61 
62 #ifndef IDX_TO_OFF
63 #define	IDX_TO_OFF(idx) (((vm_ooffset_t)(idx)) << PAGE_SHIFT)
64 #endif
65 
66 #if  __FreeBSD_version < 1300051
67 #define	VM_ALLOC_BUSY_FLAGS VM_ALLOC_NOBUSY
68 #else
69 #define	VM_ALLOC_BUSY_FLAGS  VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY
70 #endif
71 
72 
73 #if __FreeBSD_version < 1300072
74 #define	dmu_page_lock(m)	vm_page_lock(m)
75 #define	dmu_page_unlock(m)	vm_page_unlock(m)
76 #else
77 #define	dmu_page_lock(m)
78 #define	dmu_page_unlock(m)
79 #endif
80 
81 static int
82 dmu_buf_hold_array(objset_t *os, uint64_t object, uint64_t offset,
83     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
84 {
85 	dnode_t *dn;
86 	int err;
87 
88 	err = dnode_hold(os, object, FTAG, &dn);
89 	if (err)
90 		return (err);
91 
92 	err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
93 	    numbufsp, dbpp, DMU_READ_PREFETCH);
94 
95 	dnode_rele(dn, FTAG);
96 
97 	return (err);
98 }
99 
100 int
101 dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
102     vm_page_t *ma, dmu_tx_t *tx)
103 {
104 	dmu_buf_t **dbp;
105 	struct sf_buf *sf;
106 	int numbufs, i;
107 	int err;
108 
109 	if (size == 0)
110 		return (0);
111 
112 	err = dmu_buf_hold_array(os, object, offset, size,
113 	    FALSE, FTAG, &numbufs, &dbp);
114 	if (err)
115 		return (err);
116 
117 	for (i = 0; i < numbufs; i++) {
118 		int tocpy, copied, thiscpy;
119 		int bufoff;
120 		dmu_buf_t *db = dbp[i];
121 		caddr_t va;
122 
123 		ASSERT(size > 0);
124 		ASSERT3U(db->db_size, >=, PAGESIZE);
125 
126 		bufoff = offset - db->db_offset;
127 		tocpy = (int)MIN(db->db_size - bufoff, size);
128 
129 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
130 
131 		if (tocpy == db->db_size)
132 			dmu_buf_will_fill(db, tx);
133 		else
134 			dmu_buf_will_dirty(db, tx);
135 
136 		for (copied = 0; copied < tocpy; copied += PAGESIZE) {
137 			ASSERT3U(ptoa((*ma)->pindex), ==,
138 			    db->db_offset + bufoff);
139 			thiscpy = MIN(PAGESIZE, tocpy - copied);
140 			va = zfs_map_page(*ma, &sf);
141 			bcopy(va, (char *)db->db_data + bufoff, thiscpy);
142 			zfs_unmap_page(sf);
143 			ma += 1;
144 			bufoff += PAGESIZE;
145 		}
146 
147 		if (tocpy == db->db_size)
148 			dmu_buf_fill_done(db, tx);
149 
150 		offset += tocpy;
151 		size -= tocpy;
152 	}
153 	dmu_buf_rele_array(dbp, numbufs, FTAG);
154 	return (err);
155 }
156 
157 int
158 dmu_read_pages(objset_t *os, uint64_t object, vm_page_t *ma, int count,
159     int *rbehind, int *rahead, int last_size)
160 {
161 	struct sf_buf *sf;
162 	vm_object_t vmobj;
163 	vm_page_t m;
164 	dmu_buf_t **dbp;
165 	dmu_buf_t *db;
166 	caddr_t va;
167 	int numbufs, i;
168 	int bufoff, pgoff, tocpy;
169 	int mi, di;
170 	int err;
171 
172 	ASSERT3U(ma[0]->pindex + count - 1, ==, ma[count - 1]->pindex);
173 	ASSERT(last_size <= PAGE_SIZE);
174 
175 	err = dmu_buf_hold_array(os, object, IDX_TO_OFF(ma[0]->pindex),
176 	    IDX_TO_OFF(count - 1) + last_size, TRUE, FTAG, &numbufs, &dbp);
177 	if (err != 0)
178 		return (err);
179 
180 #ifdef ZFS_DEBUG
181 	IMPLY(last_size < PAGE_SIZE, *rahead == 0);
182 	if (dbp[0]->db_offset != 0 || numbufs > 1) {
183 		for (i = 0; i < numbufs; i++) {
184 			ASSERT(ISP2(dbp[i]->db_size));
185 			ASSERT((dbp[i]->db_offset % dbp[i]->db_size) == 0);
186 			ASSERT3U(dbp[i]->db_size, ==, dbp[0]->db_size);
187 		}
188 	}
189 #endif
190 
191 	vmobj = ma[0]->object;
192 	zfs_vmobject_wlock_12(vmobj);
193 
194 	db = dbp[0];
195 	for (i = 0; i < *rbehind; i++) {
196 		m = vm_page_grab_unlocked(vmobj, ma[0]->pindex - 1 - i,
197 		    VM_ALLOC_NORMAL | VM_ALLOC_NOWAIT | VM_ALLOC_BUSY_FLAGS);
198 		if (m == NULL)
199 			break;
200 		if (!vm_page_none_valid(m)) {
201 			ASSERT3U(m->valid, ==, VM_PAGE_BITS_ALL);
202 			vm_page_do_sunbusy(m);
203 			break;
204 		}
205 		ASSERT(m->dirty == 0);
206 		ASSERT(!pmap_page_is_write_mapped(m));
207 
208 		ASSERT(db->db_size > PAGE_SIZE);
209 		bufoff = IDX_TO_OFF(m->pindex) % db->db_size;
210 		va = zfs_map_page(m, &sf);
211 		bcopy((char *)db->db_data + bufoff, va, PAGESIZE);
212 		zfs_unmap_page(sf);
213 		vm_page_valid(m);
214 		dmu_page_lock(m);
215 		if ((m->busy_lock & VPB_BIT_WAITERS) != 0)
216 			vm_page_activate(m);
217 		else
218 			vm_page_deactivate(m);
219 		dmu_page_unlock(m);
220 		vm_page_do_sunbusy(m);
221 	}
222 	*rbehind = i;
223 
224 	bufoff = IDX_TO_OFF(ma[0]->pindex) % db->db_size;
225 	pgoff = 0;
226 	for (mi = 0, di = 0; mi < count && di < numbufs; ) {
227 		if (pgoff == 0) {
228 			m = ma[mi];
229 			if (m != bogus_page) {
230 				vm_page_assert_xbusied(m);
231 				ASSERT(vm_page_none_valid(m));
232 				ASSERT(m->dirty == 0);
233 				ASSERT(!pmap_page_is_write_mapped(m));
234 				va = zfs_map_page(m, &sf);
235 			}
236 		}
237 		if (bufoff == 0)
238 			db = dbp[di];
239 
240 		if (m != bogus_page) {
241 			ASSERT3U(IDX_TO_OFF(m->pindex) + pgoff, ==,
242 			    db->db_offset + bufoff);
243 		}
244 
245 		/*
246 		 * We do not need to clamp the copy size by the file
247 		 * size as the last block is zero-filled beyond the
248 		 * end of file anyway.
249 		 */
250 		tocpy = MIN(db->db_size - bufoff, PAGESIZE - pgoff);
251 		if (m != bogus_page)
252 			bcopy((char *)db->db_data + bufoff, va + pgoff, tocpy);
253 
254 		pgoff += tocpy;
255 		ASSERT(pgoff <= PAGESIZE);
256 		if (pgoff == PAGESIZE) {
257 			if (m != bogus_page) {
258 				zfs_unmap_page(sf);
259 				vm_page_valid(m);
260 			}
261 			ASSERT(mi < count);
262 			mi++;
263 			pgoff = 0;
264 		}
265 
266 		bufoff += tocpy;
267 		ASSERT(bufoff <= db->db_size);
268 		if (bufoff == db->db_size) {
269 			ASSERT(di < numbufs);
270 			di++;
271 			bufoff = 0;
272 		}
273 	}
274 
275 #ifdef ZFS_DEBUG
276 	/*
277 	 * Three possibilities:
278 	 * - last requested page ends at a buffer boundary and , thus,
279 	 *   all pages and buffers have been iterated;
280 	 * - all requested pages are filled, but the last buffer
281 	 *   has not been exhausted;
282 	 *   the read-ahead is possible only in this case;
283 	 * - all buffers have been read, but the last page has not been
284 	 *   fully filled;
285 	 *   this is only possible if the file has only a single buffer
286 	 *   with a size that is not a multiple of the page size.
287 	 */
288 	if (mi == count) {
289 		ASSERT(di >= numbufs - 1);
290 		IMPLY(*rahead != 0, di == numbufs - 1);
291 		IMPLY(*rahead != 0, bufoff != 0);
292 		ASSERT(pgoff == 0);
293 	}
294 	if (di == numbufs) {
295 		ASSERT(mi >= count - 1);
296 		ASSERT(*rahead == 0);
297 		IMPLY(pgoff == 0, mi == count);
298 		if (pgoff != 0) {
299 			ASSERT(mi == count - 1);
300 			ASSERT((dbp[0]->db_size & PAGE_MASK) != 0);
301 		}
302 	}
303 #endif
304 	if (pgoff != 0) {
305 		ASSERT(m != bogus_page);
306 		bzero(va + pgoff, PAGESIZE - pgoff);
307 		zfs_unmap_page(sf);
308 		vm_page_valid(m);
309 	}
310 
311 	for (i = 0; i < *rahead; i++) {
312 		m = vm_page_grab_unlocked(vmobj, ma[count - 1]->pindex + 1 + i,
313 		    VM_ALLOC_NORMAL | VM_ALLOC_NOWAIT | VM_ALLOC_BUSY_FLAGS);
314 		if (m == NULL)
315 			break;
316 		if (!vm_page_none_valid(m)) {
317 			ASSERT3U(m->valid, ==, VM_PAGE_BITS_ALL);
318 			vm_page_do_sunbusy(m);
319 			break;
320 		}
321 		ASSERT(m->dirty == 0);
322 		ASSERT(!pmap_page_is_mapped(m));
323 
324 		ASSERT(db->db_size > PAGE_SIZE);
325 		bufoff = IDX_TO_OFF(m->pindex) % db->db_size;
326 		tocpy = MIN(db->db_size - bufoff, PAGESIZE);
327 		va = zfs_map_page(m, &sf);
328 		bcopy((char *)db->db_data + bufoff, va, tocpy);
329 		if (tocpy < PAGESIZE) {
330 			ASSERT(i == *rahead - 1);
331 			ASSERT((db->db_size & PAGE_MASK) != 0);
332 			bzero(va + tocpy, PAGESIZE - tocpy);
333 		}
334 		zfs_unmap_page(sf);
335 		vm_page_valid(m);
336 		dmu_page_lock(m);
337 		if ((m->busy_lock & VPB_BIT_WAITERS) != 0)
338 			vm_page_activate(m);
339 		else
340 			vm_page_deactivate(m);
341 		dmu_page_unlock(m);
342 		vm_page_do_sunbusy(m);
343 	}
344 	*rahead = i;
345 	zfs_vmobject_wunlock_12(vmobj);
346 
347 	dmu_buf_rele_array(dbp, numbufs, FTAG);
348 	return (0);
349 }
350