2 * Copyright (c) 2010-2011 IBM
5 * Chunqiang Tang <ctang@us.ibm.com>
7 * This work is licensed under the terms of the GNU GPL, version 2.
8 * See the COPYING file in the top-level directory.
11 /*=============================================================================
12 * A short description: this is the header of the FVD block device driver.
13 *============================================================================*/
19 #include <sys/ioctl.h>
20 #include "qemu-common.h"
21 #include "block/block_int.h"
22 #include "qemu/option.h"
23 #include "qemu/osdep.h"
24 #include "qemu/queue.h"
25 #include "qemu/timer.h"
26 #include "block/block.h"
27 #include "block/blksim.h"
28 #include "block/fvd-ext.h"
30 #define FVD_MAGIC (('Q' << 24) | ('C' << 16) | (0xF5 << 8) | 0xA9)
33 extern bool in_qemu_tool
;
35 /* Profile-directed prefetch. (to be implemented). */
36 typedef struct __attribute__ ((__packed__
)) PrefetchProfileEntry
{
37 int64_t offset
; /* in bytes */
39 /* In the unit of FvdHeader.prefetch_profile_entry_len_unit, i.e.,
40 * len_in_bytes = len * FvdHeader.unit_of_PrefetchProfileEntry_len. */
42 } PrefetchProfileEntry
;
45 * The FVD format consists of:
46 * + Header fields of FvdHeader.
47 * + Bitmap, starting on a 4KB page boundary at a location specified by
48 * FvdHeader.bitmap_offset.
49 * + Table, starting on a 4KB page boundary at a location specified by
50 * FvdHeader.table_offset.
51 * + Journal, starting on a 4KB page boundary at a location specified by
52 * FvdHeader.journal_offset.
53 * + Prefetch profile entries, starting on a 4KB page boundary at a location
54 * specified by FvdHeader.prefetch_profile_offset. (to be implemented)
55 * + Virtual disk data, starting on a 4KB page boundary. Optionally, disk
56 * data can be stored in a separate data file specified by
57 * FvdHeader.data_file.
59 typedef struct __attribute__ ((__packed__
)) FvdHeader
{
63 /* This field is set to TRUE after whole-image prefetching finishes. */
64 int32_t all_data_in_fvd_img
;
66 int64_t virtual_disk_size
; /* in bytes. Disk size perceived by the VM. */
67 int64_t metadata_size
; /* in bytes. */
69 char base_img_fmt
[16];
70 int64_t base_img_size
; /* in bytes. */
71 int64_t bitmap_offset
; /* in bytes. Aligned on DEF_PAGE_SIZE. */
72 int64_t bitmap_size
; /* in bytes. Rounded up to DEF_PAGE_SIZE */
73 int32_t block_size
; /* in bytes. */
74 int32_t copy_on_read
; /* TRUE or FALSE */
75 int64_t max_outstanding_copy_on_read_data
; /* in bytes. */
77 /* If (data_file[0]==0), the FVD metadata and data are stored in one file.*/
79 char data_file_fmt
[16];
81 /******** Begin: for prefetching. *******************************/
82 /* in seconds. -1 means disable whole image prefetching. */
83 int32_t prefetch_start_delay
;
85 /* in bytes. Aligned on DEF_PAGE_SIZE. (to be implemented) */
86 int64_t prefetch_profile_offset
;
88 /* Number of PrefetchProfileEntry. (to be implemented) */
89 int64_t prefetch_profile_entries
;
91 int32_t num_prefetch_slots
; /* Max number of outstanding prefetch writes. */
92 int32_t bytes_per_prefetch
; /* For whole image prefetching. */
93 int32_t prefetch_read_throughput_measure_time
; /* in milliseconds. */
94 int32_t prefetch_write_throughput_measure_time
; /* in milliseconds. */
96 /* Controls the calculation of the moving average of throughput. Must be a
97 * value between [0,100].
98 * actual_normalized_alpha = * prefetch_perf_calc_alpha / 100.0 */
99 int32_t prefetch_perf_calc_alpha
;
101 int32_t prefetch_min_read_throughput
; /* in KB/second. */
102 int32_t prefetch_min_write_throughput
; /* in KB/second. */
103 int32_t prefetch_max_read_throughput
; /* in KB/second. */
104 int32_t prefetch_max_write_throughput
; /* in KB/second. */
106 /* in milliseconds. When prefetch read/write throughput is low, prefetch
107 * pauses for a random time uniformly distributed in
108 * [0, prefetch_throttle_time]. */
109 int32_t prefetch_throttle_time
;
110 /******** End: for prefetching. *******************************/
112 /******** Begin: for compact image. *****************************/
113 int32_t compact_image
; /* TRUE or FALSE */
114 int64_t table_offset
; /* in bytes. */
115 int64_t chunk_size
; /* in bytes. */
116 int64_t storage_grow_unit
; /* in bytes. */
117 char add_storage_cmd
[2048];
118 /******** End: for compact image. *******************************/
120 /******** Begin: for journal. ***********************************/
121 int64_t journal_offset
; /* in bytes. */
122 int64_t journal_size
; /* in bytes. */
123 int32_t clean_shutdown
; /* TRUE if VM's last shutdown was graceful. */
124 /******** End: for journal. *************************************/
127 * This field is TRUE if the image mandates that the storage layer
128 * (BDRVFvdState.fvd_data) must return TRUE for bdrv_has_zero_init().
129 * This is the case if the optimization described in Section 3.3.3 of the
130 * FVD-cow paper is enabled (see function search_holes()). If 'qemu-img
131 * create' sets need_zero_init to TRUE, 'qemu-img update' can be used to
132 * manually reset it to FALSE, if the user always manually pre-fills the
133 * storage (e.g., a raw partition) with zeros. If the image is stored on a
134 * file system, it already supports zero_init, and hence there is no need
135 * to manually manipulate this field.
137 int32_t need_zero_init
;
139 /* If TRUE, FVD dumps a prefetch profile after the VM shuts down.
140 * (to be implemented) */
141 int32_t generate_prefetch_profile
;
143 /* See the comment on PrefetchProfileEntry.len. (to be implemented) */
144 int32_t unit_of_PrefetchProfileEntry_len
;
146 /* in seconds. -1 means disable profile-directed prefetching.
147 * (to be implemented) */
148 int32_t profile_directed_prefetch_start_delay
;
150 /* Possible values are "no", "writethrough", "writeback", or
151 * "writenocache". (to be implemented) */
152 char write_updates_base_img
[16];
155 typedef struct BDRVFvdState
{
156 BlockDriverState
*fvd_metadata
;
157 BlockDriverState
*fvd_data
;
158 int64_t virtual_disk_size
; /*in bytes. */
159 int64_t bitmap_offset
; /* in sectors */
160 int64_t bitmap_size
; /* in bytes. */
161 int64_t data_offset
; /* in sectors. Begin of real data. */
162 int64_t nb_sectors_in_base_img
;
163 int32_t block_size
; /* in sectors. */
164 int copy_on_read
; /* TRUE or FALSE */
165 int64_t max_outstanding_copy_on_read_data
; /* in bytes. */
166 int64_t outstanding_copy_on_read_data
; /* in bytes. */
167 int data_region_prepared
; /* TRUE or FALSE */
168 QLIST_HEAD(WriteLocks
, FvdAIOCB
) write_locks
; /* All writes. */
169 QLIST_HEAD(CopyLocks
, FvdAIOCB
) copy_locks
; /* copy-on-read and CoW. */
171 /* Keep two copies of bitmap to reduce the overhead of updating the
172 * on-disk bitmap, i.e., copy-on-read and prefetching do not update the
173 * on-disk bitmap. See Section 3.3.4 of the FVD-cow paper. */
174 uint8_t *fresh_bitmap
;
175 uint8_t *stale_bitmap
;
177 /******** Begin: for prefetching. ***********************************/
178 struct FvdAIOCB
**prefetch_acb
;
179 int prefetch_state
; /* PREFETCH_STATE_RUNNING, FINISHED, or DISABLED. */
180 int prefetch_error
; /* TRUE or FALSE */
181 int num_prefetch_slots
;
182 int num_filled_prefetch_slots
;
183 int next_prefetch_read_slot
;
184 int prefetch_read_active
; /* TRUE or FALSE */
185 int pause_prefetch_requested
; /* TRUE or FALSE */
186 int prefetch_start_delay
; /* in seconds */
187 int64_t unclaimed_prefetch_region_start
;
188 int64_t prefetch_read_time
; /* in milliseconds. */
189 int64_t prefetch_write_time
; /* in milliseconds. */
190 int64_t prefetch_data_read
; /* in bytes. */
191 int64_t prefetch_data_written
; /* in bytes. */
192 double prefetch_read_throughput
; /* in bytes/millisecond. */
193 double prefetch_write_throughput
; /* in bytes/millisecond. */
194 double prefetch_min_read_throughput
; /* in bytes/millisecond. */
195 double prefetch_min_write_throughput
; /* in bytes/millisecond. */
196 int64_t prefetch_read_throughput_measure_time
; /* in millisecond. */
197 int64_t prefetch_write_throughput_measure_time
; /* in millisecond.*/
198 int prefetch_throttle_time
; /* in millisecond. */
199 int sectors_per_prefetch
;
200 QEMUTimer
*prefetch_timer
;
201 /* prefetch_perf_calc_alpha = FvdHeader.prefetch_perf_calc_alpha/100.0 */
202 double prefetch_perf_calc_alpha
;
203 /******** End: for prefetching. ***********************************/
205 /******** Begin: for compact image. *************************************/
206 uint32_t *table
; /* Mapping table stored in memory in little endian. */
207 int64_t data_storage
; /* in sectors. */
208 int64_t used_storage
; /* in sectors. */
209 int64_t chunk_size
; /* in sectors. */
210 int64_t storage_grow_unit
; /* in sectors. */
211 int64_t table_offset
; /* in sectors. */
212 char *add_storage_cmd
;
213 /******** Begin: for compact image. *************************************/
215 /******** Begin: for journal. *******************************************/
216 int64_t journal_offset
; /* in sectors. */
217 int64_t journal_size
; /* in sectors. */
218 int64_t next_journal_sector
; /* in sector. */
219 int ongoing_journal_updates
; /* Number of ongoing journal updates. */
220 int dirty_image
; /* TRUE or FALSE. */
222 /* Requests waiting for metadata flush and journal recycle to finish. */
223 QLIST_HEAD(JournalFlush
, FvdAIOCB
) wait_for_journal
;
224 /******** End: for journal. ********************************************/
227 int64_t total_copy_on_read_data
; /* in bytes. */
228 int64_t total_prefetch_data
; /* in bytes. */
232 /* Begin of data type definitions. */
235 typedef struct JournalCB
{
236 BlockDriverAIOCB
*hd_acb
;
239 QLIST_ENTRY(FvdAIOCB
) next_wait_for_journal
;
242 /* CopyLock is used by AIOWriteCB and AIOCopyCB. */
243 typedef struct CopyLock
{
244 QLIST_ENTRY(FvdAIOCB
) next
;
247 QLIST_HEAD(DependentWritesHead
, FvdAIOCB
) dependent_writes
;
250 typedef struct ChildAIOReadCB
{
251 BlockDriverAIOCB
*hd_acb
;
259 typedef struct AIOReadCB
{
262 ChildAIOReadCB read_backing
;
263 ChildAIOReadCB read_fvd
;
266 /* For copy-on-read and prefetching. */
267 typedef struct AIOCopyCB
{
268 BlockDriverAIOCB
*hd_acb
;
272 int64_t buffered_sector_begin
;
273 int64_t buffered_sector_end
;
274 int64_t last_prefetch_op_start_time
; /* For prefetch only. */
277 typedef struct AIOWriteCB
{
278 BlockDriverAIOCB
*hd_acb
;
281 QEMUIOVector
*cow_qiov
;
282 int64_t cow_start_sector
;
283 int update_table
; /* TRUE or FALSE. */
285 QLIST_ENTRY(FvdAIOCB
) next_write_lock
; /* See BDRVFvdState.write_locks */
287 /* See FvdAIOCB.write.dependent_writes. */
288 QLIST_ENTRY(FvdAIOCB
) next_dependent_write
;
291 /* For AIOStoreCompactCB and AIOLoadCompactCB. */
292 typedef struct CompactChildCB
{
293 struct FvdAIOCB
*acb
;
294 BlockDriverAIOCB
*hd_acb
;
297 /* For storing data to a compact image. */
298 typedef struct AIOStoreCompactCB
{
299 CompactChildCB one_child
;
300 CompactChildCB
*children
;
303 int finished_children
;
304 struct FvdAIOCB
*parent_acb
;
306 int soft_write
; /*TRUE if the store is caused by copy-on-read or prefetch.*/
307 QEMUIOVector
*orig_qiov
;
310 /* For loading data from a compact image. */
311 typedef struct AIOLoadCompactCB
{
312 CompactChildCB
*children
;
313 CompactChildCB one_child
;
315 int finished_children
;
316 struct FvdAIOCB
*parent_acb
;
318 QEMUIOVector
*orig_qiov
;
321 typedef struct AIOFlushCB
{
322 BlockDriverAIOCB
*data_acb
;
323 BlockDriverAIOCB
*metadata_acb
;
328 typedef struct AIOWrapperCB
{
332 typedef enum { OP_READ
= 1, OP_WRITE
, OP_COPY
, OP_STORE_COMPACT
,
333 OP_LOAD_COMPACT
, OP_WRAPPER
, OP_FLUSH
} op_type
;
336 /* For debugging memory leadk. */
337 typedef struct alloc_tracer_t
{
340 const char *alloc_file
;
346 typedef struct FvdAIOCB
{
347 BlockDriverAIOCB common
;
351 JournalCB jcb
; /* For AIOWriteCB and AIOStoreCompactCB. */
352 CopyLock copy_lock
; /* For AIOWriteCB and AIOCopyCB. */
354 /* Use a union so that all requests can efficiently share one big AIOCBInfo.*/
356 AIOWrapperCB wrapper
;
360 AIOLoadCompactCB load
;
361 AIOStoreCompactCB store
;
367 alloc_tracer_t tracer
;
369 /* Uniquely identifies a request across all processing activities. */
370 unsigned long long int uuid
;
374 static AIOCBInfo fvd_aio_pool
;
375 static BlockDriver bdrv_fvd
;
376 static QemuOptsList fvd_create_opts
;
378 /* Function prototypes. */
379 static int do_aio_write(struct FvdAIOCB
*acb
);
380 static void finish_write_data(void *opaque
, int ret
);
381 static void restart_dependent_writes(struct FvdAIOCB
*acb
);
382 static void finish_prefetch_read(void *opaque
, int ret
);
383 static int read_fvd_header(BDRVFvdState
* s
, FvdHeader
* header
);
384 static int update_fvd_header(BDRVFvdState
* s
, FvdHeader
* header
);
386 static void fvd_aio_cancel(BlockDriverAIOCB
* blockacb
);
388 static BlockDriverAIOCB
*store_data_in_compact_image(struct FvdAIOCB
*acb
,
389 int soft_write
, struct FvdAIOCB
*parent_acb
, BlockDriverState
* bs
,
390 int64_t sector_num
, QEMUIOVector
* qiov
, int nb_sectors
,
391 BlockDriverCompletionFunc
* cb
, void *opaque
);
392 static BlockDriverAIOCB
*load_data_from_compact_image(struct FvdAIOCB
*acb
,
393 struct FvdAIOCB
*parent_acb
, BlockDriverState
* bs
,
394 int64_t sector_num
, QEMUIOVector
* qiov
, int nb_sectors
,
395 BlockDriverCompletionFunc
* cb
, void *opaque
);
396 static void free_write_resource(struct FvdAIOCB
*acb
);
397 static void write_metadata_to_journal(struct FvdAIOCB
*acb
);
398 static void flush_metadata_to_disk(BlockDriverState
* bs
);
399 static void free_journal_sectors(BDRVFvdState
* s
);
400 static int fvd_create(const char *filename
, QemuOpts
*options
,
402 static int fvd_probe(const uint8_t * buf
, int buf_size
, const char *filename
);
403 static int64_t coroutine_fn
fvd_get_block_status(BlockDriverState
*bs
,
405 int nb_sectors
, int *pnum
);
406 static int fvd_flush(BlockDriverState
* bs
);
407 static BlockDriverAIOCB
*fvd_aio_readv(BlockDriverState
* bs
,
408 int64_t sector_num
, QEMUIOVector
* qiov
, int nb_sectors
,
409 BlockDriverCompletionFunc
* cb
, void *opaque
);
410 static BlockDriverAIOCB
*fvd_aio_writev(BlockDriverState
* bs
,
411 int64_t sector_num
, QEMUIOVector
* qiov
, int nb_sectors
,
412 BlockDriverCompletionFunc
* cb
, void *opaque
);
413 static BlockDriverAIOCB
*fvd_aio_flush(BlockDriverState
* bs
,
414 BlockDriverCompletionFunc
* cb
, void *opaque
);
415 static int fvd_get_info(BlockDriverState
* bs
, BlockDriverInfo
* bdi
);
416 static int fvd_update(BlockDriverState
* bs
, int argc
, char **argv
);
417 static int fvd_has_zero_init(BlockDriverState
* bs
);
419 static void fvd_read_cancel(FvdAIOCB
* acb
);
420 static void fvd_write_cancel(FvdAIOCB
* acb
);
421 static void fvd_copy_cancel(FvdAIOCB
* acb
);
422 static void fvd_load_compact_cancel(FvdAIOCB
* acb
);
423 static void fvd_store_compact_cancel(FvdAIOCB
* acb
);
424 static void fvd_wrapper_cancel(FvdAIOCB
* acb
);
426 static void flush_metadata_to_disk_on_exit (BlockDriverState
*bs
);
427 static inline BlockDriverAIOCB
*load_data(FvdAIOCB
* parent_acb
,
428 BlockDriverState
* bs
, int64_t sector_num
, QEMUIOVector
* orig_qiov
,
429 int nb_sectors
, BlockDriverCompletionFunc
* cb
, void *opaque
);
430 static inline BlockDriverAIOCB
*store_data(int soft_write
,
431 FvdAIOCB
* parent_acb
, BlockDriverState
* bs
, int64_t sector_num
,
432 QEMUIOVector
* orig_qiov
, int nb_sectors
,
433 BlockDriverCompletionFunc
* cb
, void *opaque
);
435 /* Default configurations. */
436 #define DEF_PAGE_SIZE 4096 /* bytes */
437 #define BYTES_PER_PREFETCH 1048576 /* bytes */
438 #define PREFETCH_THROTTLING_TIME 30000 /* milliseconds */
439 #define NUM_PREFETCH_SLOTS 2
440 #define PREFETCH_MIN_MEASURE_READ_TIME 100 /* milliseconds */
441 #define PREFETCH_MIN_MEASURE_WRITE_TIME 100 /* milliseconds */
442 #define PREFETCH_MIN_READ_THROUGHPUT 5120 /* KB/s */
443 #define PREFETCH_MIN_WRITE_THROUGHPUT 5120 /* KB/s */
444 #define PREFETCH_MAX_READ_THROUGHPUT 1000000000L /* KB/s */
445 #define PREFETCH_MAX_WRITE_THROUGHPUT 1000000000L /* KB/s */
446 #define PREFETCH_PERF_CALC_ALPHA 80 /* in [0,100]. */
447 #define MAX_OUTSTANDING_COPY_ON_READ_DATA 2000000 /* bytes */
448 #define MODERATE_BITMAP_SIZE 4194304L /* bytes */
449 #define CHUNK_SIZE 1048576LL /* bytes */
450 #define JOURNAL_SIZE 16777216LL /* bytes */
451 #define STORAGE_GROW_UNIT 104857600LL /* bytes */
453 /* State of BDRVFvdState.prefetch_state. */
454 #define PREFETCH_STATE_RUNNING 1
455 #define PREFETCH_STATE_FINISHED 2
456 #define PREFETCH_STATE_DISABLED 3
459 #undef ROUND_UP /* override definition from osdep.h */
460 #define ROUND_UP(x, base) ((((x)+(base)-1) / (base)) * (base))
461 #define ROUND_DOWN(x, base) ((((x) / (base)) * (base)))
462 #define BOOL(x) ((x) ? "true" : "false")
463 #define EMPTY_TABLE ((uint32_t)0xFFFFFFFF)
464 #define DIRTY_TABLE ((uint32_t)0x80000000)
465 #define READ_TABLE(entry) (le32_to_cpu(entry) & ~DIRTY_TABLE)
466 # define FVDAIOCB_MAGIC ((uint64_t)0x3A8FCE89325B976DULL)
467 # define FVD_ALLOC_MAGIC ((uint64_t)0x4A7dCEF9925B976DULL)
468 #define IS_EMPTY(entry) ((entry) == EMPTY_TABLE)
469 #define IS_DIRTY(entry) (le32_to_cpu(entry) & DIRTY_TABLE)
470 #define WRITE_TABLE(entry,id) ((entry) = cpu_to_le32(id))
471 #define READ_TABLE2(entry) \
472 ((entry)==EMPTY_TABLE ? EMPTY_TABLE : (le32_to_cpu(entry) & ~DIRTY_TABLE))
474 #define CLEAN_DIRTY(entry) \
476 if (!IS_EMPTY(entry)) \
477 entry = cpu_to_le32(le32_to_cpu(entry) & ~DIRTY_TABLE); \
480 #define CLEAN_DIRTY2(entry) \
482 ASSERT(!IS_EMPTY(entry)); \
483 entry = cpu_to_le32(le32_to_cpu(entry) & ~DIRTY_TABLE); \