HAMMER 41B/Many: Cleanup.
[dragonfly.git] / sys / vfs / hammer / hammer_recover.c
1 /*
2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
3  * 
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  * 
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  * 
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  * 
34  * $DragonFly: src/sys/vfs/hammer/hammer_recover.c,v 1.16 2008/05/06 00:21:08 dillon Exp $
35  */
36
37 #include "hammer.h"
38
39 static int hammer_check_tail_signature(hammer_fifo_tail_t tail,
40                         hammer_off_t end_off);
41 static void hammer_recover_copy_undo(hammer_off_t undo_offset,
42                         char *src, char *dst, int bytes);
43 #if 0
44 static void hammer_recover_debug_dump(int w, char *buf, int bytes);
45 #endif
46 static int hammer_recover_undo(hammer_mount_t hmp, hammer_fifo_undo_t undo,
47                         int bytes);
48
49 /*
50  * Recover a filesystem on mount
51  *
52  * NOTE: No information from the root volume has been cached in the
53  * hammer_mount structure yet, so we need to access the root volume's
54  * buffer directly.
55  */
56 int
57 hammer_recover(hammer_mount_t hmp, hammer_volume_t root_volume)
58 {
59         hammer_blockmap_t rootmap;
60         hammer_buffer_t buffer;
61         hammer_off_t scan_offset;
62         hammer_off_t bytes;
63         hammer_fifo_tail_t tail;
64         hammer_fifo_undo_t undo;
65         int error;
66
67         /*
68          * Examine the UNDO FIFO.  If it is empty the filesystem is clean
69          * and no action need be taken.
70          *
71          * NOTE: hmp->blockmap has not been initialized yet so use the
72          * root volume's ondisk buffer directly.
73          */
74         rootmap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_UNDO_INDEX];
75         hmp->flusher_undo_start = rootmap->next_offset;
76
77         if (rootmap->first_offset == rootmap->next_offset)
78                 return(0);
79
80         if (rootmap->next_offset >= rootmap->first_offset) {
81                 bytes = rootmap->next_offset - rootmap->first_offset;
82         } else {
83                 bytes = rootmap->alloc_offset - rootmap->first_offset +
84                         (rootmap->next_offset & HAMMER_OFF_LONG_MASK);
85         }
86         kprintf("HAMMER(%s) Start Recovery (%lld bytes of UNDO)\n",
87                 root_volume->ondisk->vol_name, bytes);
88         if (bytes > (rootmap->alloc_offset & HAMMER_OFF_LONG_MASK)) {
89                 kprintf("Undo size is absurd, unable to mount\n");
90                 return(EIO);
91         }
92
93         /*
94          * Scan the UNDOs backwards.
95          */
96         scan_offset = rootmap->next_offset;
97         buffer = NULL;
98         if (scan_offset > rootmap->alloc_offset) {
99                 kprintf("HAMMER(%s) UNDO record at %016llx FIFO overflow\n",
100                         root_volume->ondisk->vol_name,
101                         scan_offset);
102                 error = EIO;
103                 goto done;
104         }
105
106         while ((int64_t)bytes > 0) {
107                 if (hammer_debug_general & 0x0080)
108                         kprintf("scan_offset %016llx\n", scan_offset);
109                 if (scan_offset == HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0)) {
110                         scan_offset = rootmap->alloc_offset;
111                         continue;
112                 }
113                 if (scan_offset - sizeof(*tail) <
114                     HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0)) {
115                         kprintf("HAMMER(%s) UNDO record at %016llx FIFO "
116                                 "underflow\n",
117                                 root_volume->ondisk->vol_name,
118                                 scan_offset);
119                         error = EIO;
120                         break;
121                 }
122                 tail = hammer_bread(hmp, scan_offset - sizeof(*tail),
123                                     &error, &buffer);
124                 if (error) {
125                         kprintf("HAMMER(%s) Unable to read UNDO TAIL "
126                                 "at %016llx\n",
127                                 root_volume->ondisk->vol_name,
128                                 scan_offset - sizeof(*tail));
129                         break;
130                 }
131
132                 if (hammer_check_tail_signature(tail, scan_offset) != 0) {
133                         kprintf("HAMMER(%s) Illegal UNDO TAIL signature "
134                                 "at %016llx\n",
135                                 root_volume->ondisk->vol_name,
136                                 scan_offset - sizeof(*tail));
137                         error = EIO;
138                         break;
139                 }
140                 undo = (void *)((char *)tail + sizeof(*tail) - tail->tail_size);
141
142                 error = hammer_recover_undo(hmp, undo,
143                                 HAMMER_BUFSIZE -
144                                 (int)((char *)undo - (char *)buffer->ondisk));
145                 if (error) {
146                         kprintf("HAMMER(%s) UNDO record at %016llx failed\n",
147                                 root_volume->ondisk->vol_name,
148                                 scan_offset - tail->tail_size);
149                         break;
150                 }
151                 scan_offset -= tail->tail_size;
152                 bytes -= tail->tail_size;
153         }
154 done:
155         /*
156          * Reload flusher_undo_start to kick off the UNDO sequencing.
157          */
158         hmp->flusher_undo_start = rootmap->next_offset;
159         if (buffer)
160                 hammer_rel_buffer(buffer, 0);
161         return (error);
162 }
163
164 static int
165 hammer_check_tail_signature(hammer_fifo_tail_t tail, hammer_off_t end_off)
166 {
167         int max_bytes;
168
169         max_bytes = ((end_off - sizeof(*tail)) & HAMMER_BUFMASK);
170         max_bytes += sizeof(*tail);
171
172         /*
173          * tail overlaps buffer boundary
174          */
175         if (((end_off - sizeof(*tail)) ^ (end_off - 1)) & ~HAMMER_BUFMASK64) {
176                 return(1);
177         }
178
179         /*
180          * signature check, the tail signature is allowed to be the head
181          * signature only for 8-byte PADs.
182          */
183         switch(tail->tail_signature) {
184         case HAMMER_TAIL_SIGNATURE:
185                 break;
186         case HAMMER_HEAD_SIGNATURE:
187                 if (tail->tail_type != HAMMER_HEAD_TYPE_PAD ||
188                     tail->tail_size != sizeof(*tail)) {
189                         return(2);
190                 }
191                 break;
192         }
193
194         /*
195          * The undo structure must not overlap a buffer boundary.
196          */
197         if (tail->tail_size < 0 || tail->tail_size > max_bytes) {
198                 return(3);
199         }
200         return(0);
201 }
202
203 static int
204 hammer_recover_undo(hammer_mount_t hmp, hammer_fifo_undo_t undo, int bytes)
205 {
206         hammer_fifo_tail_t tail;
207         hammer_volume_t volume;
208         hammer_buffer_t buffer;
209         int zone;
210         int error;
211         int vol_no;
212         int max_bytes;
213         u_int32_t offset;
214
215         /*
216          * Basic sanity checks
217          */
218         if (bytes < HAMMER_HEAD_ALIGN) {
219                 kprintf("HAMMER: Undo alignment error (%d)\n", bytes);
220                 return(EIO);
221         }
222         if (undo->head.hdr_signature != HAMMER_HEAD_SIGNATURE) {
223                 kprintf("HAMMER: Bad head signature %04x\n", 
224                         undo->head.hdr_signature);
225                 return(EIO);
226         }
227         if (undo->head.hdr_size < HAMMER_HEAD_ALIGN ||
228             undo->head.hdr_size > bytes) {
229                 kprintf("HAMMER: Bad size %d\n", bytes);
230                 return(EIO);
231         }
232
233         /*
234          * Skip PAD records.  Note that PAD records also do not require
235          * a tail.
236          */
237         if (undo->head.hdr_type == HAMMER_HEAD_TYPE_PAD)
238                 return(0);
239
240         /*
241          * Check the tail
242          */
243         bytes = undo->head.hdr_size;
244         tail = (void *)((char *)undo + bytes - sizeof(*tail));
245         if (tail->tail_size != undo->head.hdr_size) {
246                 kprintf("HAMMER: Bad tail size %d\n", tail->tail_size);
247                 return(EIO);
248         }
249         if (tail->tail_type != undo->head.hdr_type) {
250                 kprintf("HAMMER: Bad tail type %d\n", tail->tail_type);
251                 return(EIO);
252         }
253
254         /*
255          * Only process UNDO records
256          */
257         if (undo->head.hdr_type != HAMMER_HEAD_TYPE_UNDO)
258                 return(0);
259
260         /*
261          * Validate the UNDO record.
262          */
263         max_bytes = undo->head.hdr_size - sizeof(*undo) - sizeof(*tail);
264         if (undo->undo_data_bytes < 0 || undo->undo_data_bytes > max_bytes) {
265                 kprintf("HAMMER: Corrupt UNDO record, undo_data_bytes %d/%d\n",
266                         undo->undo_data_bytes, max_bytes);
267                 return(EIO);
268         }
269
270         /*
271          * The undo offset may only be a zone-1 or zone-2 offset.
272          *
273          * Currently we only support a zone-1 offset representing the
274          * volume header.
275          */
276         zone = HAMMER_ZONE_DECODE(undo->undo_offset);
277         offset = undo->undo_offset & HAMMER_BUFMASK;
278
279         if (offset + undo->undo_data_bytes > HAMMER_BUFSIZE) {
280                 kprintf("HAMMER: Corrupt UNDO record, bad offset\n");
281                 return (EIO);
282         }
283
284         switch(zone) {
285         case HAMMER_ZONE_RAW_VOLUME_INDEX:
286                 vol_no = HAMMER_VOL_DECODE(undo->undo_offset);
287                 volume = hammer_get_volume(hmp, vol_no, &error);
288                 if (volume == NULL) {
289                         kprintf("HAMMER: UNDO record, "
290                                 "cannot access volume %d\n", vol_no);
291                         break;
292                 }
293                 hammer_modify_volume(NULL, volume, NULL, 0);
294                 hammer_recover_copy_undo(undo->undo_offset,
295                                          (char *)(undo + 1),
296                                          (char *)volume->ondisk + offset,
297                                          undo->undo_data_bytes);
298                 hammer_modify_volume_done(volume);
299                 hammer_io_flush(&volume->io);
300                 hammer_rel_volume(volume, 0);
301                 break;
302         case HAMMER_ZONE_RAW_BUFFER_INDEX:
303                 buffer = hammer_get_buffer(hmp, undo->undo_offset, 0, &error);
304                 if (buffer == NULL) {
305                         kprintf("HAMMER: UNDO record, "
306                                 "cannot access buffer %016llx\n",
307                                 undo->undo_offset);
308                         break;
309                 }
310                 hammer_modify_buffer(NULL, buffer, NULL, 0);
311                 hammer_recover_copy_undo(undo->undo_offset,
312                                          (char *)(undo + 1),
313                                          (char *)buffer->ondisk + offset,
314                                          undo->undo_data_bytes);
315                 hammer_modify_buffer_done(buffer);
316                 hammer_io_flush(&buffer->io);
317                 hammer_rel_buffer(buffer, 0);
318                 break;
319         default:
320                 kprintf("HAMMER: Corrupt UNDO record\n");
321                 error = EIO;
322         }
323         return (error);
324 }
325
326 static void
327 hammer_recover_copy_undo(hammer_off_t undo_offset, 
328                          char *src, char *dst, int bytes)
329 {
330         hkprintf("U");
331         if (hammer_debug_general & 0x0080)
332                 kprintf("NDO %016llx: %d\n", undo_offset, bytes);
333 #if 0
334         kprintf("UNDO %016llx:", undo_offset);
335         hammer_recover_debug_dump(22, dst, bytes);
336         kprintf("%22s", "to:");
337         hammer_recover_debug_dump(22, src, bytes);
338 #endif
339         bcopy(src, dst, bytes);
340 }
341
342 #if 0
343
344 static void
345 hammer_recover_debug_dump(int w, char *buf, int bytes)
346 {
347         int i;
348
349         for (i = 0; i < bytes; ++i) {
350                 if (i && (i & 15) == 0)
351                         kprintf("\n%*.*s", w, w, "");
352                 kprintf(" %02x", (unsigned char)buf[i]);
353         }
354         kprintf("\n");
355 }
356
357 #endif