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authorEric Blake <eblake@redhat.com>2017-10-11 22:47:17 -0500
committerKevin Wolf <kwolf@redhat.com>2017-10-26 14:45:57 +0200
commitefa6e2ed643c770153eeacace410c06f15360cd9 (patch)
treeb1b42cdc1e893ad6a06355c999b17066947b9456 /block/blkdebug.c
parent033d9fc203a90f567b16119906cd06f7e65a397c (diff)
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block: Align block status requests
Any device that has request_alignment greater than 512 should be unable to report status at a finer granularity; it may also be simpler for such devices to be guaranteed that the block layer has rounded things out to the granularity boundary (the way the block layer already rounds all other I/O out). Besides, getting the code correct for super-sector alignment also benefits us for the fact that our public interface now has byte granularity, even though none of our drivers have byte-level callbacks. Add an assertion in blkdebug that proves that the block layer never requests status of unaligned sections, similar to what it does on other requests (while still keeping the generic helper in place for when future patches add a throttle driver). Note that iotest 177 already covers this (it would fail if you use just the blkdebug.c hunk without the io.c changes). Meanwhile, we can drop assertions in callers that no longer have to pass in sector-aligned addresses. There is a mid-function scope added for 'count' and 'longret', for a couple of reasons: first, an upcoming patch will add an 'if' statement that checks whether a driver has an old- or new-style callback, and can conveniently use the same scope for less indentation churn at that time. Second, since we are trying to get rid of sector-based computations, wrapping things in a scope makes it easier to group and see what will be deleted in a final cleanup patch once all drivers have been converted to the new-style callback. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/blkdebug.c')
-rw-r--r--block/blkdebug.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/block/blkdebug.c b/block/blkdebug.c
index dfdf9b9..e216699 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -627,6 +627,17 @@ static int coroutine_fn blkdebug_co_pdiscard(BlockDriverState *bs,
return bdrv_co_pdiscard(bs->file->bs, offset, bytes);
}
+static int64_t coroutine_fn blkdebug_co_get_block_status(
+ BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum,
+ BlockDriverState **file)
+{
+ assert(QEMU_IS_ALIGNED(sector_num | nb_sectors,
+ DIV_ROUND_UP(bs->bl.request_alignment,
+ BDRV_SECTOR_SIZE)));
+ return bdrv_co_get_block_status_from_file(bs, sector_num, nb_sectors,
+ pnum, file);
+}
+
static void blkdebug_close(BlockDriverState *bs)
{
BDRVBlkdebugState *s = bs->opaque;
@@ -896,7 +907,7 @@ static BlockDriver bdrv_blkdebug = {
.bdrv_co_flush_to_disk = blkdebug_co_flush,
.bdrv_co_pwrite_zeroes = blkdebug_co_pwrite_zeroes,
.bdrv_co_pdiscard = blkdebug_co_pdiscard,
- .bdrv_co_get_block_status = bdrv_co_get_block_status_from_file,
+ .bdrv_co_get_block_status = blkdebug_co_get_block_status,
.bdrv_debug_event = blkdebug_debug_event,
.bdrv_debug_breakpoint = blkdebug_debug_breakpoint,