2 * Copyright (c) 2008 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
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8 * modification, are permitted provided that the following conditions
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34 * $DragonFly: src/sys/vfs/hammer/hammer_undo.c,v 1.12 2008/05/04 19:57:42 dillon Exp $
38 * HAMMER undo - undo buffer/FIFO management.
43 static int hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2);
45 RB_GENERATE2(hammer_und_rb_tree, hammer_undo, rb_node,
46 hammer_und_rb_compare, hammer_off_t, offset);
49 * Convert a zone-3 undo offset into a zone-2 buffer offset.
52 hammer_undo_lookup(hammer_mount_t hmp, hammer_off_t zone3_off, int *errorp)
54 hammer_volume_t root_volume;
55 hammer_blockmap_t undomap;
56 struct hammer_blockmap_layer2 *layer2;
57 hammer_off_t result_offset;
60 KKASSERT((zone3_off & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_UNDO);
61 root_volume = hammer_get_root_volume(hmp, errorp);
64 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
65 KKASSERT(HAMMER_ZONE_DECODE(undomap->alloc_offset) == HAMMER_ZONE_UNDO_INDEX);
66 KKASSERT (zone3_off < undomap->alloc_offset);
68 i = (zone3_off & HAMMER_OFF_SHORT_MASK) / HAMMER_LARGEBLOCK_SIZE;
69 layer2 = &root_volume->ondisk->vol0_undo_array[i];
70 result_offset = layer2->u.phys_offset +
71 (zone3_off & HAMMER_LARGEBLOCK_MASK64);
73 hammer_rel_volume(root_volume, 0);
74 return(result_offset);
78 * Generate an UNDO record for the block of data at the specified zone1
81 * The recovery code will execute UNDOs in reverse order, allowing overlaps.
82 * All the UNDOs are executed together so if we already laid one down we
83 * do not have to lay another one down for the same range.
86 hammer_generate_undo(hammer_transaction_t trans, hammer_io_t io,
87 hammer_off_t zone_off, void *base, int len)
89 hammer_volume_t root_volume;
90 hammer_volume_ondisk_t ondisk;
91 hammer_blockmap_t undomap;
92 hammer_buffer_t buffer = NULL;
93 hammer_fifo_undo_t undo;
94 hammer_fifo_tail_t tail;
95 hammer_off_t next_offset;
100 * Enter the offset into our undo history. If there is an existing
101 * undo we do not have to generate a new one.
103 if (hammer_enter_undo_history(trans->hmp, zone_off, len) == EALREADY)
106 root_volume = trans->rootvol;
107 ondisk = root_volume->ondisk;
108 undomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
110 /* no undo recursion */
111 hammer_modify_volume(NULL, root_volume, NULL, 0);
115 * Allocate space in the FIFO
117 bytes = ((len + HAMMER_HEAD_ALIGN_MASK) & ~HAMMER_HEAD_ALIGN_MASK) +
118 sizeof(struct hammer_fifo_undo) +
119 sizeof(struct hammer_fifo_tail);
120 if (hammer_undo_space(trans->hmp) < bytes + HAMMER_BUFSIZE*2)
121 panic("hammer: insufficient undo FIFO space!");
123 next_offset = undomap->next_offset;
128 if (undomap->next_offset == undomap->alloc_offset) {
129 next_offset = HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0);
130 undomap->next_offset = next_offset;
131 kprintf("undo zone's next_offset wrapped\n");
134 undo = hammer_bread(trans->hmp, next_offset, &error, &buffer);
135 hammer_modify_buffer(NULL, buffer, NULL, 0);
138 * We raced another thread, try again.
140 if (undomap->next_offset != next_offset) {
141 hammer_modify_buffer_done(buffer);
146 * The FIFO entry would cross a buffer boundary, PAD to the end
147 * of the buffer and try again. Due to our data alignment, the
148 * worst case (smallest) PAD record is 8 bytes. PAD records only
149 * populate the first 8 bytes of hammer_fifo_head and the tail may
150 * be at the same offset as the head.
152 if ((next_offset ^ (next_offset + bytes)) & ~HAMMER_BUFMASK64) {
153 bytes = HAMMER_BUFSIZE - ((int)next_offset & HAMMER_BUFMASK);
154 tail = (void *)((char *)undo + bytes - sizeof(*tail));
155 if ((void *)undo != (void *)tail) {
156 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
157 tail->tail_type = HAMMER_HEAD_TYPE_PAD;
158 tail->tail_size = bytes;
160 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
161 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD;
162 undo->head.hdr_size = bytes;
163 undomap->next_offset += bytes;
164 hammer_modify_buffer_done(buffer);
167 if (hammer_debug_general & 0x0080)
168 kprintf("undo %016llx %d %d\n", next_offset, bytes, len);
171 * We're good, create the entry.
173 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
174 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO;
175 undo->head.hdr_size = bytes;
176 undo->head.reserved01 = 0;
177 undo->head.hdr_crc = 0;
178 undo->undo_offset = zone_off;
179 undo->undo_data_bytes = len;
180 bcopy(base, undo + 1, len);
182 tail = (void *)((char *)undo + bytes - sizeof(*tail));
183 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
184 tail->tail_type = HAMMER_HEAD_TYPE_UNDO;
185 tail->tail_size = bytes;
187 undo->head.hdr_crc = crc32(undo, bytes);
188 undomap->next_offset += bytes;
190 hammer_modify_buffer_done(buffer);
191 hammer_modify_volume_done(root_volume);
194 hammer_rel_buffer(buffer, 0);
201 * It is not necessary to layout an undo record for the same address space
202 * multiple times. Maintain a cache of recent undo's.
206 * Enter an undo into the history. Return EALREADY if the request completely
207 * covers a previous request.
210 hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset, int bytes)
215 node = RB_LOOKUP(hammer_und_rb_tree, &hmp->rb_undo_root, offset);
217 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry);
218 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry);
219 if (bytes <= node->bytes)
224 if (hmp->undo_alloc != HAMMER_MAX_UNDOS) {
225 node = &hmp->undos[hmp->undo_alloc++];
227 node = TAILQ_FIRST(&hmp->undo_lru_list);
228 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry);
229 RB_REMOVE(hammer_und_rb_tree, &hmp->rb_undo_root, node);
231 node->offset = offset;
233 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry);
234 onode = RB_INSERT(hammer_und_rb_tree, &hmp->rb_undo_root, node);
235 KKASSERT(onode == NULL);
240 hammer_clear_undo_history(hammer_mount_t hmp)
242 RB_INIT(&hmp->rb_undo_root);
243 TAILQ_INIT(&hmp->undo_lru_list);
248 * Misc helper routines. Return available space and total space.
251 hammer_undo_used(hammer_mount_t hmp)
253 hammer_blockmap_t rootmap;
257 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
259 if (rootmap->first_offset <= rootmap->next_offset) {
260 bytes = rootmap->next_offset - rootmap->first_offset;
262 bytes = rootmap->alloc_offset - rootmap->first_offset +
263 (rootmap->next_offset & HAMMER_OFF_LONG_MASK);
265 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK;
266 KKASSERT(bytes <= max_bytes);
271 hammer_undo_space(hammer_mount_t hmp)
273 hammer_blockmap_t rootmap;
276 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
277 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK;
278 return(max_bytes - hammer_undo_used(hmp));
282 hammer_undo_max(hammer_mount_t hmp)
284 hammer_blockmap_t rootmap;
287 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
288 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK;
294 hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2)
296 if (node1->offset < node2->offset)
298 if (node1->offset > node2->offset)