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-rw-r--r--block/io.c124
1 files changed, 81 insertions, 43 deletions
diff --git a/block/io.c b/block/io.c
index 890d3c073b..1c4dc4b1a1 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1813,80 +1813,102 @@ int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs,
* BDRV_BLOCK_ZERO where possible; otherwise, the result may omit those
* bits particularly if it allows for a larger value in 'pnum'.
*
- * If 'sector_num' is beyond the end of the disk image the return value is
+ * If 'offset' is beyond the end of the disk image the return value is
* BDRV_BLOCK_EOF and 'pnum' is set to 0.
*
- * 'pnum' is set to the number of sectors (including and immediately following
- * the specified sector) that are known to be in the same
- * allocated/unallocated state.
- *
- * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes
+ * 'bytes' is the max value 'pnum' should be set to. If bytes goes
* beyond the end of the disk image it will be clamped; if 'pnum' is set to
* the end of the image, then the returned value will include BDRV_BLOCK_EOF.
*
- * If returned value is positive, BDRV_BLOCK_OFFSET_VALID bit is set, and
- * 'file' is non-NULL, then '*file' points to the BDS which the sector range
- * is allocated in.
+ * 'pnum' is set to the number of bytes (including and immediately
+ * following the specified offset) that are easily known to be in the
+ * same allocated/unallocated state. Note that a second call starting
+ * at the original offset plus returned pnum may have the same status.
+ * The returned value is non-zero on success except at end-of-file.
+ *
+ * Returns negative errno on failure. Otherwise, if the
+ * BDRV_BLOCK_OFFSET_VALID bit is set, 'map' and 'file' (if non-NULL) are
+ * set to the host mapping and BDS corresponding to the guest offset.
*/
-static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
- bool want_zero,
- int64_t sector_num,
- int nb_sectors, int *pnum,
- BlockDriverState **file)
-{
- int64_t total_sectors;
- int64_t n;
- int64_t ret, ret2;
+static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs,
+ bool want_zero,
+ int64_t offset, int64_t bytes,
+ int64_t *pnum, int64_t *map,
+ BlockDriverState **file)
+{
+ int64_t total_size;
+ int64_t n; /* bytes */
+ int64_t ret;
+ int64_t local_map = 0;
BlockDriverState *local_file = NULL;
+ int count; /* sectors */
assert(pnum);
*pnum = 0;
- total_sectors = bdrv_nb_sectors(bs);
- if (total_sectors < 0) {
- ret = total_sectors;
+ total_size = bdrv_getlength(bs);
+ if (total_size < 0) {
+ ret = total_size;
goto early_out;
}
- if (sector_num >= total_sectors) {
+ if (offset >= total_size) {
ret = BDRV_BLOCK_EOF;
goto early_out;
}
- if (!nb_sectors) {
+ if (!bytes) {
ret = 0;
goto early_out;
}
- n = total_sectors - sector_num;
- if (n < nb_sectors) {
- nb_sectors = n;
+ n = total_size - offset;
+ if (n < bytes) {
+ bytes = n;
}
if (!bs->drv->bdrv_co_get_block_status) {
- *pnum = nb_sectors;
+ *pnum = bytes;
ret = BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED;
- if (sector_num + nb_sectors == total_sectors) {
+ if (offset + bytes == total_size) {
ret |= BDRV_BLOCK_EOF;
}
if (bs->drv->protocol_name) {
- ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE);
+ ret |= BDRV_BLOCK_OFFSET_VALID;
+ local_map = offset;
local_file = bs;
}
goto early_out;
}
bdrv_inc_in_flight(bs);
- ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum,
+ /*
+ * TODO: Rather than require aligned offsets, we could instead
+ * round to the driver's request_alignment here, then touch up
+ * count afterwards back to the caller's expectations.
+ */
+ assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
+ /*
+ * The contract allows us to return pnum smaller than bytes, even
+ * if the next query would see the same status; we truncate the
+ * request to avoid overflowing the driver's 32-bit interface.
+ */
+ bytes = MIN(bytes, BDRV_REQUEST_MAX_BYTES);
+ ret = bs->drv->bdrv_co_get_block_status(bs, offset >> BDRV_SECTOR_BITS,
+ bytes >> BDRV_SECTOR_BITS, &count,
&local_file);
if (ret < 0) {
- *pnum = 0;
goto out;
}
+ if (ret & BDRV_BLOCK_OFFSET_VALID) {
+ local_map = ret & BDRV_BLOCK_OFFSET_MASK;
+ }
+ *pnum = count * BDRV_SECTOR_SIZE;
if (ret & BDRV_BLOCK_RAW) {
assert(ret & BDRV_BLOCK_OFFSET_VALID && local_file);
- ret = bdrv_co_get_block_status(local_file, want_zero,
- ret >> BDRV_SECTOR_BITS,
- *pnum, pnum, &local_file);
+ ret = bdrv_co_block_status(local_file, want_zero, local_map,
+ *pnum, pnum, &local_map, &local_file);
+ assert(ret < 0 ||
+ QEMU_IS_ALIGNED(*pnum | local_map, BDRV_SECTOR_SIZE));
goto out;
}
@@ -1897,9 +1919,9 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
ret |= BDRV_BLOCK_ZERO;
} else if (bs->backing) {
BlockDriverState *bs2 = bs->backing->bs;
- int64_t nb_sectors2 = bdrv_nb_sectors(bs2);
+ int64_t size2 = bdrv_getlength(bs2);
- if (nb_sectors2 >= 0 && sector_num >= nb_sectors2) {
+ if (size2 >= 0 && offset >= size2) {
ret |= BDRV_BLOCK_ZERO;
}
}
@@ -1908,11 +1930,11 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
if (want_zero && local_file && local_file != bs &&
(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
(ret & BDRV_BLOCK_OFFSET_VALID)) {
- int file_pnum;
+ int64_t file_pnum;
+ int ret2;
- ret2 = bdrv_co_get_block_status(local_file, want_zero,
- ret >> BDRV_SECTOR_BITS,
- *pnum, &file_pnum, NULL);
+ ret2 = bdrv_co_block_status(local_file, want_zero, local_map,
+ *pnum, &file_pnum, NULL, NULL);
if (ret2 >= 0) {
/* Ignore errors. This is just providing extra information, it
* is useful but not necessary.
@@ -1935,13 +1957,21 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
out:
bdrv_dec_in_flight(bs);
- if (ret >= 0 && sector_num + *pnum == total_sectors) {
+ if (ret >= 0 && offset + *pnum == total_size) {
ret |= BDRV_BLOCK_EOF;
}
early_out:
if (file) {
*file = local_file;
}
+ if (map) {
+ *map = local_map;
+ }
+ if (ret >= 0) {
+ ret &= ~BDRV_BLOCK_OFFSET_MASK;
+ } else {
+ assert(INT_MIN <= ret);
+ }
return ret;
}
@@ -1956,14 +1986,22 @@ static int64_t coroutine_fn bdrv_co_get_block_status_above(BlockDriverState *bs,
BlockDriverState *p;
int64_t ret = 0;
bool first = true;
+ int64_t map = 0;
assert(bs != base);
for (p = bs; p != base; p = backing_bs(p)) {
- ret = bdrv_co_get_block_status(p, want_zero, sector_num, nb_sectors,
- pnum, file);
+ int64_t count;
+
+ ret = bdrv_co_block_status(p, want_zero,
+ sector_num * BDRV_SECTOR_SIZE,
+ nb_sectors * BDRV_SECTOR_SIZE, &count,
+ &map, file);
if (ret < 0) {
break;
}
+ assert(QEMU_IS_ALIGNED(count | map, BDRV_SECTOR_SIZE));
+ ret |= map;
+ *pnum = count >> BDRV_SECTOR_BITS;
if (ret & BDRV_BLOCK_ZERO && ret & BDRV_BLOCK_EOF && !first) {
/*
* Reading beyond the end of the file continues to read
generated by cgit v1.2.3 (git 2.26.2) at 2025-01-05 10:18:22 +0000