xref: /qemu/block/stream.c (revision 188a7bbf)
14f1043b4SStefan Hajnoczi /*
24f1043b4SStefan Hajnoczi  * Image streaming
34f1043b4SStefan Hajnoczi  *
44f1043b4SStefan Hajnoczi  * Copyright IBM, Corp. 2011
54f1043b4SStefan Hajnoczi  *
64f1043b4SStefan Hajnoczi  * Authors:
74f1043b4SStefan Hajnoczi  *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
84f1043b4SStefan Hajnoczi  *
94f1043b4SStefan Hajnoczi  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
104f1043b4SStefan Hajnoczi  * See the COPYING.LIB file in the top-level directory.
114f1043b4SStefan Hajnoczi  *
124f1043b4SStefan Hajnoczi  */
134f1043b4SStefan Hajnoczi 
144f1043b4SStefan Hajnoczi #include "trace.h"
154f1043b4SStefan Hajnoczi #include "block_int.h"
164f1043b4SStefan Hajnoczi 
174f1043b4SStefan Hajnoczi enum {
184f1043b4SStefan Hajnoczi     /*
194f1043b4SStefan Hajnoczi      * Size of data buffer for populating the image file.  This should be large
204f1043b4SStefan Hajnoczi      * enough to process multiple clusters in a single call, so that populating
214f1043b4SStefan Hajnoczi      * contiguous regions of the image is efficient.
224f1043b4SStefan Hajnoczi      */
234f1043b4SStefan Hajnoczi     STREAM_BUFFER_SIZE = 512 * 1024, /* in bytes */
244f1043b4SStefan Hajnoczi };
254f1043b4SStefan Hajnoczi 
265094a6c0SStefan Hajnoczi #define SLICE_TIME 100000000ULL /* ns */
275094a6c0SStefan Hajnoczi 
285094a6c0SStefan Hajnoczi typedef struct {
295094a6c0SStefan Hajnoczi     int64_t next_slice_time;
305094a6c0SStefan Hajnoczi     uint64_t slice_quota;
315094a6c0SStefan Hajnoczi     uint64_t dispatched;
325094a6c0SStefan Hajnoczi } RateLimit;
335094a6c0SStefan Hajnoczi 
345094a6c0SStefan Hajnoczi static int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n)
355094a6c0SStefan Hajnoczi {
365094a6c0SStefan Hajnoczi     int64_t now = qemu_get_clock_ns(rt_clock);
375094a6c0SStefan Hajnoczi 
385094a6c0SStefan Hajnoczi     if (limit->next_slice_time < now) {
395094a6c0SStefan Hajnoczi         limit->next_slice_time = now + SLICE_TIME;
405094a6c0SStefan Hajnoczi         limit->dispatched = 0;
415094a6c0SStefan Hajnoczi     }
42b21d677eSPaolo Bonzini     if (limit->dispatched == 0 || limit->dispatched + n <= limit->slice_quota) {
435094a6c0SStefan Hajnoczi         limit->dispatched += n;
44b21d677eSPaolo Bonzini         return 0;
45b21d677eSPaolo Bonzini     } else {
46b21d677eSPaolo Bonzini         limit->dispatched = n;
47b21d677eSPaolo Bonzini         return limit->next_slice_time - now;
485094a6c0SStefan Hajnoczi     }
495094a6c0SStefan Hajnoczi }
505094a6c0SStefan Hajnoczi 
515094a6c0SStefan Hajnoczi static void ratelimit_set_speed(RateLimit *limit, uint64_t speed)
525094a6c0SStefan Hajnoczi {
535094a6c0SStefan Hajnoczi     limit->slice_quota = speed / (1000000000ULL / SLICE_TIME);
545094a6c0SStefan Hajnoczi }
555094a6c0SStefan Hajnoczi 
564f1043b4SStefan Hajnoczi typedef struct StreamBlockJob {
574f1043b4SStefan Hajnoczi     BlockJob common;
585094a6c0SStefan Hajnoczi     RateLimit limit;
594f1043b4SStefan Hajnoczi     BlockDriverState *base;
60c8c3080fSMarcelo Tosatti     char backing_file_id[1024];
614f1043b4SStefan Hajnoczi } StreamBlockJob;
624f1043b4SStefan Hajnoczi 
634f1043b4SStefan Hajnoczi static int coroutine_fn stream_populate(BlockDriverState *bs,
644f1043b4SStefan Hajnoczi                                         int64_t sector_num, int nb_sectors,
654f1043b4SStefan Hajnoczi                                         void *buf)
664f1043b4SStefan Hajnoczi {
674f1043b4SStefan Hajnoczi     struct iovec iov = {
684f1043b4SStefan Hajnoczi         .iov_base = buf,
694f1043b4SStefan Hajnoczi         .iov_len  = nb_sectors * BDRV_SECTOR_SIZE,
704f1043b4SStefan Hajnoczi     };
714f1043b4SStefan Hajnoczi     QEMUIOVector qiov;
724f1043b4SStefan Hajnoczi 
734f1043b4SStefan Hajnoczi     qemu_iovec_init_external(&qiov, &iov, 1);
744f1043b4SStefan Hajnoczi 
754f1043b4SStefan Hajnoczi     /* Copy-on-read the unallocated clusters */
764f1043b4SStefan Hajnoczi     return bdrv_co_copy_on_readv(bs, sector_num, nb_sectors, &qiov);
774f1043b4SStefan Hajnoczi }
784f1043b4SStefan Hajnoczi 
795a67a104SMarcelo Tosatti static void close_unused_images(BlockDriverState *top, BlockDriverState *base,
805a67a104SMarcelo Tosatti                                 const char *base_id)
815a67a104SMarcelo Tosatti {
825a67a104SMarcelo Tosatti     BlockDriverState *intermediate;
835a67a104SMarcelo Tosatti     intermediate = top->backing_hd;
845a67a104SMarcelo Tosatti 
855a67a104SMarcelo Tosatti     while (intermediate) {
865a67a104SMarcelo Tosatti         BlockDriverState *unused;
875a67a104SMarcelo Tosatti 
885a67a104SMarcelo Tosatti         /* reached base */
895a67a104SMarcelo Tosatti         if (intermediate == base) {
905a67a104SMarcelo Tosatti             break;
915a67a104SMarcelo Tosatti         }
925a67a104SMarcelo Tosatti 
935a67a104SMarcelo Tosatti         unused = intermediate;
945a67a104SMarcelo Tosatti         intermediate = intermediate->backing_hd;
955a67a104SMarcelo Tosatti         unused->backing_hd = NULL;
965a67a104SMarcelo Tosatti         bdrv_delete(unused);
975a67a104SMarcelo Tosatti     }
985a67a104SMarcelo Tosatti     top->backing_hd = base;
995a67a104SMarcelo Tosatti }
1005a67a104SMarcelo Tosatti 
1014f1043b4SStefan Hajnoczi static void coroutine_fn stream_run(void *opaque)
1024f1043b4SStefan Hajnoczi {
1034f1043b4SStefan Hajnoczi     StreamBlockJob *s = opaque;
1044f1043b4SStefan Hajnoczi     BlockDriverState *bs = s->common.bs;
105c8c3080fSMarcelo Tosatti     BlockDriverState *base = s->base;
1064f1043b4SStefan Hajnoczi     int64_t sector_num, end;
1074f1043b4SStefan Hajnoczi     int ret = 0;
10804120e3bSAnthony Liguori     int n = 0;
1094f1043b4SStefan Hajnoczi     void *buf;
1104f1043b4SStefan Hajnoczi 
1114f1043b4SStefan Hajnoczi     s->common.len = bdrv_getlength(bs);
1124f1043b4SStefan Hajnoczi     if (s->common.len < 0) {
1134f1043b4SStefan Hajnoczi         block_job_complete(&s->common, s->common.len);
1144f1043b4SStefan Hajnoczi         return;
1154f1043b4SStefan Hajnoczi     }
1164f1043b4SStefan Hajnoczi 
1174f1043b4SStefan Hajnoczi     end = s->common.len >> BDRV_SECTOR_BITS;
1184f1043b4SStefan Hajnoczi     buf = qemu_blockalign(bs, STREAM_BUFFER_SIZE);
1194f1043b4SStefan Hajnoczi 
1204f1043b4SStefan Hajnoczi     /* Turn on copy-on-read for the whole block device so that guest read
1214f1043b4SStefan Hajnoczi      * requests help us make progress.  Only do this when copying the entire
1224f1043b4SStefan Hajnoczi      * backing chain since the copy-on-read operation does not take base into
1234f1043b4SStefan Hajnoczi      * account.
1244f1043b4SStefan Hajnoczi      */
1254f1043b4SStefan Hajnoczi     if (!base) {
1264f1043b4SStefan Hajnoczi         bdrv_enable_copy_on_read(bs);
1274f1043b4SStefan Hajnoczi     }
1284f1043b4SStefan Hajnoczi 
1294f1043b4SStefan Hajnoczi     for (sector_num = 0; sector_num < end; sector_num += n) {
1304513eafeSPaolo Bonzini         uint64_t delay_ns = 0;
131f9749f28SPaolo Bonzini         bool copy;
1324513eafeSPaolo Bonzini 
1334513eafeSPaolo Bonzini wait:
1344513eafeSPaolo Bonzini         /* Note that even when no rate limit is applied we need to yield
1354513eafeSPaolo Bonzini          * with no pending I/O here so that qemu_aio_flush() returns.
1364513eafeSPaolo Bonzini          */
1374513eafeSPaolo Bonzini         block_job_sleep_ns(&s->common, rt_clock, delay_ns);
1384f1043b4SStefan Hajnoczi         if (block_job_is_cancelled(&s->common)) {
1394f1043b4SStefan Hajnoczi             break;
1404f1043b4SStefan Hajnoczi         }
1414f1043b4SStefan Hajnoczi 
142f9749f28SPaolo Bonzini         ret = bdrv_co_is_allocated(bs, sector_num,
1434f1043b4SStefan Hajnoczi                                    STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n);
144f9749f28SPaolo Bonzini         if (ret == 1) {
145f9749f28SPaolo Bonzini             /* Allocated in the top, no need to copy.  */
146f9749f28SPaolo Bonzini             copy = false;
147f9749f28SPaolo Bonzini         } else {
148f9749f28SPaolo Bonzini             /* Copy if allocated in the intermediate images.  Limit to the
149f9749f28SPaolo Bonzini              * known-unallocated area [sector_num, sector_num+n).  */
150*188a7bbfSPaolo Bonzini             ret = bdrv_co_is_allocated_above(bs->backing_hd, base,
151*188a7bbfSPaolo Bonzini                                              sector_num, n, &n);
152f9749f28SPaolo Bonzini             copy = (ret == 1);
153f9749f28SPaolo Bonzini         }
1544f1043b4SStefan Hajnoczi         trace_stream_one_iteration(s, sector_num, n, ret);
155f9749f28SPaolo Bonzini         if (ret >= 0 && copy) {
1565094a6c0SStefan Hajnoczi             if (s->common.speed) {
1574513eafeSPaolo Bonzini                 delay_ns = ratelimit_calculate_delay(&s->limit, n);
1585094a6c0SStefan Hajnoczi                 if (delay_ns > 0) {
1594513eafeSPaolo Bonzini                     goto wait;
1605094a6c0SStefan Hajnoczi                 }
1615094a6c0SStefan Hajnoczi             }
1624f1043b4SStefan Hajnoczi             ret = stream_populate(bs, sector_num, n, buf);
1634f1043b4SStefan Hajnoczi         }
1644f1043b4SStefan Hajnoczi         if (ret < 0) {
1654f1043b4SStefan Hajnoczi             break;
1664f1043b4SStefan Hajnoczi         }
167c8c3080fSMarcelo Tosatti         ret = 0;
1684f1043b4SStefan Hajnoczi 
1694f1043b4SStefan Hajnoczi         /* Publish progress */
1704f1043b4SStefan Hajnoczi         s->common.offset += n * BDRV_SECTOR_SIZE;
1714f1043b4SStefan Hajnoczi     }
1724f1043b4SStefan Hajnoczi 
1734f1043b4SStefan Hajnoczi     if (!base) {
1744f1043b4SStefan Hajnoczi         bdrv_disable_copy_on_read(bs);
1754f1043b4SStefan Hajnoczi     }
1764f1043b4SStefan Hajnoczi 
1773e914655SPaolo Bonzini     if (!block_job_is_cancelled(&s->common) && sector_num == end && ret == 0) {
178f6133defSPaolo Bonzini         const char *base_id = NULL, *base_fmt = NULL;
179c8c3080fSMarcelo Tosatti         if (base) {
180c8c3080fSMarcelo Tosatti             base_id = s->backing_file_id;
181f6133defSPaolo Bonzini             if (base->drv) {
182f6133defSPaolo Bonzini                 base_fmt = base->drv->format_name;
183c8c3080fSMarcelo Tosatti             }
184f6133defSPaolo Bonzini         }
185f6133defSPaolo Bonzini         ret = bdrv_change_backing_file(bs, base_id, base_fmt);
1865a67a104SMarcelo Tosatti         close_unused_images(bs, base, base_id);
1874f1043b4SStefan Hajnoczi     }
1884f1043b4SStefan Hajnoczi 
1894f1043b4SStefan Hajnoczi     qemu_vfree(buf);
1904f1043b4SStefan Hajnoczi     block_job_complete(&s->common, ret);
1914f1043b4SStefan Hajnoczi }
1924f1043b4SStefan Hajnoczi 
193882ec7ceSStefan Hajnoczi static void stream_set_speed(BlockJob *job, int64_t speed, Error **errp)
1945094a6c0SStefan Hajnoczi {
1955094a6c0SStefan Hajnoczi     StreamBlockJob *s = container_of(job, StreamBlockJob, common);
1965094a6c0SStefan Hajnoczi 
197882ec7ceSStefan Hajnoczi     if (speed < 0) {
198882ec7ceSStefan Hajnoczi         error_set(errp, QERR_INVALID_PARAMETER, "speed");
1999e6636c7SStefan Hajnoczi         return;
2005094a6c0SStefan Hajnoczi     }
201882ec7ceSStefan Hajnoczi     ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE);
2025094a6c0SStefan Hajnoczi }
2035094a6c0SStefan Hajnoczi 
2044f1043b4SStefan Hajnoczi static BlockJobType stream_job_type = {
2054f1043b4SStefan Hajnoczi     .instance_size = sizeof(StreamBlockJob),
2064f1043b4SStefan Hajnoczi     .job_type      = "stream",
2075094a6c0SStefan Hajnoczi     .set_speed     = stream_set_speed,
2084f1043b4SStefan Hajnoczi };
2094f1043b4SStefan Hajnoczi 
210fd7f8c65SStefan Hajnoczi void stream_start(BlockDriverState *bs, BlockDriverState *base,
211c83c66c3SStefan Hajnoczi                   const char *base_id, int64_t speed,
212c83c66c3SStefan Hajnoczi                   BlockDriverCompletionFunc *cb,
213fd7f8c65SStefan Hajnoczi                   void *opaque, Error **errp)
2144f1043b4SStefan Hajnoczi {
2154f1043b4SStefan Hajnoczi     StreamBlockJob *s;
2164f1043b4SStefan Hajnoczi 
217c83c66c3SStefan Hajnoczi     s = block_job_create(&stream_job_type, bs, speed, cb, opaque, errp);
2184f1043b4SStefan Hajnoczi     if (!s) {
219fd7f8c65SStefan Hajnoczi         return;
2204f1043b4SStefan Hajnoczi     }
2214f1043b4SStefan Hajnoczi 
2224f1043b4SStefan Hajnoczi     s->base = base;
223c8c3080fSMarcelo Tosatti     if (base_id) {
224c8c3080fSMarcelo Tosatti         pstrcpy(s->backing_file_id, sizeof(s->backing_file_id), base_id);
225c8c3080fSMarcelo Tosatti     }
2264f1043b4SStefan Hajnoczi 
227fa4478d5SPaolo Bonzini     s->common.co = qemu_coroutine_create(stream_run);
228fa4478d5SPaolo Bonzini     trace_stream_start(bs, base, s, s->common.co, opaque);
229fa4478d5SPaolo Bonzini     qemu_coroutine_enter(s->common.co, s);
2304f1043b4SStefan Hajnoczi }
231