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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21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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34 * $DragonFly: src/sys/vfs/hammer/hammer_undo.c,v 1.8 2008/05/02 01:00:42 dillon Exp $
38 * HAMMER undo - undo buffer/FIFO management.
44 * Convert a zone-3 undo offset into a zone-2 buffer offset.
47 hammer_undo_lookup(hammer_mount_t hmp, hammer_off_t zone3_off, int *errorp)
49 hammer_volume_t root_volume;
50 hammer_blockmap_t undomap;
51 struct hammer_blockmap_layer2 *layer2;
52 hammer_off_t result_offset;
55 KKASSERT((zone3_off & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_UNDO);
56 root_volume = hammer_get_root_volume(hmp, errorp);
59 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
60 KKASSERT(HAMMER_ZONE_DECODE(undomap->alloc_offset) == HAMMER_ZONE_UNDO_INDEX);
61 KKASSERT (zone3_off < undomap->alloc_offset);
63 i = (zone3_off & HAMMER_OFF_SHORT_MASK) / HAMMER_LARGEBLOCK_SIZE;
64 layer2 = &root_volume->ondisk->vol0_undo_array[i];
65 result_offset = layer2->u.phys_offset +
66 (zone3_off & HAMMER_LARGEBLOCK_MASK64);
68 hammer_rel_volume(root_volume, 0);
69 return(result_offset);
73 * Generate an UNDO record for the block of data at the specified zone1
77 hammer_generate_undo(hammer_transaction_t trans, hammer_io_t io,
78 hammer_off_t zone_off, void *base, int len)
80 hammer_volume_t root_volume;
81 hammer_volume_ondisk_t ondisk;
82 hammer_blockmap_t undomap;
83 hammer_buffer_t buffer = NULL;
84 struct hammer_blockmap_layer2 *layer2;
85 hammer_fifo_undo_t undo;
86 hammer_fifo_tail_t tail;
87 hammer_off_t next_offset;
88 hammer_off_t result_offset;
93 root_volume = trans->rootvol;
94 ondisk = root_volume->ondisk;
95 undomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
97 /* no undo recursion */
98 hammer_modify_volume(NULL, root_volume, NULL, 0);
104 * Allocate space in the FIFO
106 bytes = ((len + HAMMER_HEAD_ALIGN_MASK) & ~HAMMER_HEAD_ALIGN_MASK) +
107 sizeof(struct hammer_fifo_undo) +
108 sizeof(struct hammer_fifo_tail);
109 if (hammer_undo_space(trans->hmp) < bytes + HAMMER_BUFSIZE*2)
110 panic("hammer: insufficient undo FIFO space!");
112 next_offset = undomap->next_offset;
117 if (undomap->next_offset == undomap->alloc_offset) {
118 next_offset = HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0);
119 undomap->next_offset = next_offset;
120 kprintf("undo zone's next_offset wrapped\n");
123 i = (next_offset & HAMMER_OFF_SHORT_MASK) / HAMMER_LARGEBLOCK_SIZE;
124 layer2 = &root_volume->ondisk->vol0_undo_array[i];
125 result_offset = layer2->u.phys_offset +
126 (next_offset & HAMMER_LARGEBLOCK_MASK64);
128 undo = hammer_bread(trans->hmp, result_offset, &error, &buffer);
131 * We raced another thread, try again.
133 if (undomap->next_offset != next_offset)
136 hammer_modify_buffer(NULL, buffer, NULL, 0);
139 * The FIFO entry would cross a buffer boundary, PAD to the end
140 * of the buffer and try again. Due to our data alignment, the
141 * worst case (smallest) PAD record is 8 bytes. PAD records only
142 * populate the first 8 bytes of hammer_fifo_head and the tail may
143 * be at the same offset as the head.
145 if ((result_offset ^ (result_offset + bytes)) & ~HAMMER_BUFMASK64) {
146 bytes = HAMMER_BUFSIZE - ((int)next_offset & HAMMER_BUFMASK);
147 tail = (void *)((char *)undo + bytes - sizeof(*tail));
148 if ((void *)undo != (void *)tail) {
149 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
150 tail->tail_type = HAMMER_HEAD_TYPE_PAD;
151 tail->tail_size = bytes;
153 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
154 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD;
155 undo->head.hdr_size = bytes;
156 undomap->next_offset += bytes;
157 hammer_modify_buffer_done(buffer);
160 if (hammer_debug_general & 0x0080)
161 kprintf("undo %016llx %d %d\n", result_offset, bytes, len);
164 * We're good, create the entry.
166 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
167 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO;
168 undo->head.hdr_size = bytes;
169 undo->head.reserved01 = 0;
170 undo->head.hdr_crc = 0;
171 undo->undo_offset = zone_off;
172 undo->undo_data_bytes = len;
173 bcopy(base, undo + 1, len);
175 tail = (void *)((char *)undo + bytes - sizeof(*tail));
176 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
177 tail->tail_type = HAMMER_HEAD_TYPE_UNDO;
178 tail->tail_size = bytes;
180 undo->head.hdr_crc = crc32(undo, bytes);
181 hammer_modify_buffer_done(buffer);
184 * Update the undo offset space in the IO XXX
187 undomap->next_offset += bytes;
188 hammer_modify_volume_done(root_volume);
191 hammer_rel_buffer(buffer, 0);
196 hammer_undo_space(hammer_mount_t hmp)
198 hammer_blockmap_t rootmap;
202 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
204 if (rootmap->first_offset <= rootmap->next_offset) {
205 bytes = (int)(rootmap->next_offset - rootmap->first_offset);
207 bytes = (int)(rootmap->alloc_offset - rootmap->first_offset +
208 rootmap->next_offset);
210 max_bytes = (int)(rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK);
211 return(max_bytes - bytes);
215 hammer_undo_max(hammer_mount_t hmp)
217 hammer_blockmap_t rootmap;
220 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
221 max_bytes = (int)(rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK);