[v4,12/16] block/io: support int64_t bytes in bdrv_co_do_copy_on_readv()

Commit Message

Vladimir Sementsov-Ogievskiy Dec. 11, 2020, 6:39 p.m. UTC

We are generally moving to int64_t for both offset and bytes parameters
on all io paths.

Main motivation is realization of 64-bit write_zeroes operation for
fast zeroing large disk chunks, up to the whole disk.

We chose signed type, to be consistent with off_t (which is signed) and
with possibility for signed return type (where negative value means
error).

So, prepare bdrv_co_do_copy_on_readv() now.

'bytes' type widening, so callers are safe. Look at the function
itself:

bytes, skip_bytes and progress become int64_t.

bdrv_round_to_clusters() is OK, cluster_bytes now may be large.
trace_bdrv_co_do_copy_on_readv() is OK

looping through cluster_bytes is still OK.

pnum is still capped to max_transfer, and to MAX_BOUNCE_BUFFER when we
are going to do COR operation. Therefor calculations in
qemu_iovec_from_buf() and bdrv_driver_preadv() should not change.

Signed-off-by: Vladimir Sementsov-Ogievskiy <[e-mail]>
---
 block/io.c         | 8 +++++---
 block/trace-events | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

Comments

Eric Blake Jan. 22, 2021, 4:34 p.m. UTC | #1

On 12/11/20 12:39 PM, Vladimir Sementsov-Ogievskiy wrote:
> We are generally moving to int64_t for both offset and bytes parameters
> on all io paths.
> 
> Main motivation is realization of 64-bit write_zeroes operation for
> fast zeroing large disk chunks, up to the whole disk.
> 
> We chose signed type, to be consistent with off_t (which is signed) and
> with possibility for signed return type (where negative value means
> error).
> 
> So, prepare bdrv_co_do_copy_on_readv() now.
> 
> 'bytes' type widening, so callers are safe. Look at the function
> itself:
> 
> bytes, skip_bytes and progress become int64_t.
> 
> bdrv_round_to_clusters() is OK, cluster_bytes now may be large.
> trace_bdrv_co_do_copy_on_readv() is OK
> 
> looping through cluster_bytes is still OK.
> 
> pnum is still capped to max_transfer, and to MAX_BOUNCE_BUFFER when we
> are going to do COR operation. Therefor calculations in
> qemu_iovec_from_buf() and bdrv_driver_preadv() should not change.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <[e-mail]>
> ---
>  block/io.c         | 8 +++++---
>  block/trace-events | 2 +-
>  2 files changed, 6 insertions(+), 4 deletions(-)
> 

Reviewed-by: Eric Blake <[e-mail]>

Patch

diff --git a/block/io.c b/block/io.c
index b499998f54..d8c07fac56 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1289,7 +1289,7 @@  bdrv_driver_pwritev_compressed(BlockDriverState *bs, int64_t offset,
 }
 
 static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
-        int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+        int64_t offset, int64_t bytes, QEMUIOVector *qiov,
         size_t qiov_offset, int flags)
 {
     BlockDriverState *bs = child->bs;
@@ -1304,13 +1304,15 @@  static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
     BlockDriver *drv = bs->drv;
     int64_t cluster_offset;
     int64_t cluster_bytes;
-    size_t skip_bytes;
+    int64_t skip_bytes;
     int ret;
     int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer,
                                     BDRV_REQUEST_MAX_BYTES);
-    unsigned int progress = 0;
+    int64_t progress = 0;
     bool skip_write;
 
+    bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
+
     if (!drv) {
         return -ENOMEDIUM;
     }
diff --git a/block/trace-events b/block/trace-events
index 8368f4acb0..a5f6ffb7da 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -14,7 +14,7 @@  blk_root_detach(void *child, void *blk, void *bs) "child %p blk %p bs %p"
 bdrv_co_preadv(void *bs, int64_t offset, int64_t nbytes, unsigned int flags) "bs %p offset %"PRId64" nbytes %"PRId64" flags 0x%x"
 bdrv_co_pwritev(void *bs, int64_t offset, int64_t nbytes, unsigned int flags) "bs %p offset %"PRId64" nbytes %"PRId64" flags 0x%x"
 bdrv_co_pwrite_zeroes(void *bs, int64_t offset, int count, int flags) "bs %p offset %"PRId64" count %d flags 0x%x"
-bdrv_co_do_copy_on_readv(void *bs, int64_t offset, unsigned int bytes, int64_t cluster_offset, int64_t cluster_bytes) "bs %p offset %"PRId64" bytes %u cluster_offset %"PRId64" cluster_bytes %"PRId64
+bdrv_co_do_copy_on_readv(void *bs, int64_t offset, int64_t bytes, int64_t cluster_offset, int64_t cluster_bytes) "bs %p offset %" PRId64 " bytes %" PRId64 " cluster_offset %" PRId64 " cluster_bytes %" PRId64
 bdrv_co_copy_range_from(void *src, uint64_t src_offset, void *dst, uint64_t dst_offset, uint64_t bytes, int read_flags, int write_flags) "src %p offset %"PRIu64" dst %p offset %"PRIu64" bytes %"PRIu64" rw flags 0x%x 0x%x"
 bdrv_co_copy_range_to(void *src, uint64_t src_offset, void *dst, uint64_t dst_offset, uint64_t bytes, int read_flags, int write_flags) "src %p offset %"PRIu64" dst %p offset %"PRIu64" bytes %"PRIu64" rw flags 0x%x 0x%x"