block: Add "file" output parameter to block status query functions

The added parameter can be used to return the BDS pointer which the
valid offset is referring to. Its value should be ignored unless
BDRV_BLOCK_OFFSET_VALID in ret is set.

Until block drivers fill in the right value, let's clear it explicitly
right before calling .bdrv_get_block_status.

The "bs->file" condition in bdrv_co_get_block_status is kept now to keep iotest
case 102 passing, and will be fixed once all drivers return the right file
pointer.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1453780743-16806-2-git-send-email-famz@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 28 insertions, 12 deletions

diff --git a/block/io.c b/block/io.c
index 5bb353a8ca..ea040bef22 100644
--- a/block/io.c
+++ b/block/io.c
@@ -664,6 +664,7 @@ int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num,
 int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
 {
     int64_t target_sectors, ret, nb_sectors, sector_num = 0;
+    BlockDriverState *file;
     int n;
 
     target_sectors = bdrv_nb_sectors(bs);
@@ -676,7 +677,7 @@ int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
         if (nb_sectors <= 0) {
             return 0;
         }
-        ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
+        ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n, &file);
         if (ret < 0) {
             error_report("error getting block status at sector %" PRId64 ": %s",
                          sector_num, strerror(-ret));
@@ -1466,6 +1467,7 @@ int bdrv_flush_all(void)
 typedef struct BdrvCoGetBlockStatusData {
     BlockDriverState *bs;
     BlockDriverState *base;
+    BlockDriverState **file;
     int64_t sector_num;
     int nb_sectors;
     int *pnum;
@@ -1487,10 +1489,14 @@ typedef struct BdrvCoGetBlockStatusData {
  *
  * 'nb_sectors' is the max value 'pnum' should be set to.  If nb_sectors goes
  * beyond the end of the disk image it will be clamped.
+ *
+ * If returned value is positive and BDRV_BLOCK_OFFSET_VALID bit is set, 'file'
+ * points to the BDS which the sector range is allocated in.
  */
 static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
                                                      int64_t sector_num,
-                                                     int nb_sectors, int *pnum)
+                                                     int nb_sectors, int *pnum,
+                                                     BlockDriverState **file)
 {
     int64_t total_sectors;
     int64_t n;
@@ -1520,7 +1526,9 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
         return ret;
     }
 
-    ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);
+    *file = NULL;
+    ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum,
+                                            file);
     if (ret < 0) {
         *pnum = 0;
         return ret;
@@ -1529,7 +1537,7 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
     if (ret & BDRV_BLOCK_RAW) {
         assert(ret & BDRV_BLOCK_OFFSET_VALID);
         return bdrv_get_block_status(bs->file->bs, ret >> BDRV_SECTOR_BITS,
-                                     *pnum, pnum);
+                                     *pnum, pnum, file);
     }
 
     if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) {
@@ -1549,10 +1557,11 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
     if (bs->file &&
         (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
         (ret & BDRV_BLOCK_OFFSET_VALID)) {
+        BlockDriverState *file2;
         int file_pnum;
 
         ret2 = bdrv_co_get_block_status(bs->file->bs, ret >> BDRV_SECTOR_BITS,
-                                        *pnum, &file_pnum);
+                                        *pnum, &file_pnum, &file2);
         if (ret2 >= 0) {
             /* Ignore errors.  This is just providing extra information, it
              * is useful but not necessary.
@@ -1577,14 +1586,15 @@ static int64_t coroutine_fn bdrv_co_get_block_status_above(BlockDriverState *bs,
         BlockDriverState *base,
         int64_t sector_num,
         int nb_sectors,
-        int *pnum)
+        int *pnum,
+        BlockDriverState **file)
 {
     BlockDriverState *p;
     int64_t ret = 0;
 
     assert(bs != base);
     for (p = bs; p != base; p = backing_bs(p)) {
-        ret = bdrv_co_get_block_status(p, sector_num, nb_sectors, pnum);
+        ret = bdrv_co_get_block_status(p, sector_num, nb_sectors, pnum, file);
         if (ret < 0 || ret & BDRV_BLOCK_ALLOCATED) {
             break;
         }
@@ -1603,7 +1613,8 @@ static void coroutine_fn bdrv_get_block_status_above_co_entry(void *opaque)
     data->ret = bdrv_co_get_block_status_above(data->bs, data->base,
                                                data->sector_num,
                                                data->nb_sectors,
-                                               data->pnum);
+                                               data->pnum,
+                                               data->file);
     data->done = true;
 }
 
@@ -1615,12 +1626,14 @@ static void coroutine_fn bdrv_get_block_status_above_co_entry(void *opaque)
 int64_t bdrv_get_block_status_above(BlockDriverState *bs,
                                     BlockDriverState *base,
                                     int64_t sector_num,
-                                    int nb_sectors, int *pnum)
+                                    int nb_sectors, int *pnum,
+                                    BlockDriverState **file)
 {
     Coroutine *co;
     BdrvCoGetBlockStatusData data = {
         .bs = bs,
         .base = base,
+        .file = file,
         .sector_num = sector_num,
         .nb_sectors = nb_sectors,
         .pnum = pnum,
@@ -1644,16 +1657,19 @@ int64_t bdrv_get_block_status_above(BlockDriverState *bs,
 
 int64_t bdrv_get_block_status(BlockDriverState *bs,
                               int64_t sector_num,
-                              int nb_sectors, int *pnum)
+                              int nb_sectors, int *pnum,
+                              BlockDriverState **file)
 {
     return bdrv_get_block_status_above(bs, backing_bs(bs),
-                                       sector_num, nb_sectors, pnum);
+                                       sector_num, nb_sectors, pnum, file);
 }
 
 int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,
                                    int nb_sectors, int *pnum)
 {
-    int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum);
+    BlockDriverState *file;
+    int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum,
+                                        &file);
     if (ret < 0) {
         return ret;
     }