diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 9bbdbd63d7..0c1eee1778 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -119,14 +119,14 @@ BlockBackend *blk_by_dev(void *dev);
 BlockBackend *blk_by_qdev_id(const char *id, Error **errp);
 void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque);
 int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
-                               unsigned int bytes, QEMUIOVector *qiov,
+                               int64_t bytes, QEMUIOVector *qiov,
                                BdrvRequestFlags flags);
 int coroutine_fn blk_co_pwritev_part(BlockBackend *blk, int64_t offset,
-                                     unsigned int bytes,
+                                     int64_t bytes,
                                      QEMUIOVector *qiov, size_t qiov_offset,
                                      BdrvRequestFlags flags);
 int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
-                               unsigned int bytes, QEMUIOVector *qiov,
+                               int64_t bytes, QEMUIOVector *qiov,
                                BdrvRequestFlags flags);
 
 static inline int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset,
@@ -148,13 +148,13 @@ static inline int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset,
 }
 
 int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
-                      int bytes, BdrvRequestFlags flags);
+                      int64_t bytes, BdrvRequestFlags flags);
 BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
-                                  int bytes, BdrvRequestFlags flags,
+                                  int64_t bytes, BdrvRequestFlags flags,
                                   BlockCompletionFunc *cb, void *opaque);
 int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags);
-int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int bytes);
-int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int bytes,
+int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int64_t bytes);
+int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int64_t bytes,
                BdrvRequestFlags flags);
 int64_t blk_getlength(BlockBackend *blk);
 void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr);
@@ -167,14 +167,14 @@ BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
                             BlockCompletionFunc *cb, void *opaque);
 BlockAIOCB *blk_aio_flush(BlockBackend *blk,
                           BlockCompletionFunc *cb, void *opaque);
-BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int bytes,
+BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes,
                              BlockCompletionFunc *cb, void *opaque);
 void blk_aio_cancel(BlockAIOCB *acb);
 void blk_aio_cancel_async(BlockAIOCB *acb);
 int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
 BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
                           BlockCompletionFunc *cb, void *opaque);
-int blk_co_pdiscard(BlockBackend *blk, int64_t offset, int bytes);
+int blk_co_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes);
 int blk_co_flush(BlockBackend *blk);
 int blk_flush(BlockBackend *blk);
 int blk_commit_all(void);
@@ -233,12 +233,12 @@ int blk_get_open_flags_from_root_state(BlockBackend *blk);
 void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
                   BlockCompletionFunc *cb, void *opaque);
 int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
-                                      int bytes, BdrvRequestFlags flags);
+                                      int64_t bytes, BdrvRequestFlags flags);
 int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
-                          int bytes);
+                          int64_t bytes);
 int blk_truncate(BlockBackend *blk, int64_t offset, bool exact,
                  PreallocMode prealloc, Error **errp);
-int blk_pdiscard(BlockBackend *blk, int64_t offset, int bytes);
+int blk_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes);
 int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
                      int64_t pos, int size);
 int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size);
@@ -259,7 +259,7 @@ void blk_unregister_buf(BlockBackend *blk, void *host);
 
 int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
                                    BlockBackend *blk_out, int64_t off_out,
-                                   int bytes, BdrvRequestFlags read_flags,
+                                   int64_t bytes, BdrvRequestFlags read_flags,
                                    BdrvRequestFlags write_flags);
 
 const BdrvChild *blk_root(BlockBackend *blk);
diff --git a/block/block-backend.c b/block/block-backend.c
index 38ae413826..b3f6edfc70 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1110,11 +1110,11 @@ void blk_set_disable_request_queuing(BlockBackend *blk, bool disable)
 }
 
 static int blk_check_byte_request(BlockBackend *blk, int64_t offset,
-                                  size_t size)
+                                  int64_t bytes)
 {
     int64_t len;
 
-    if (size > INT_MAX) {
+    if (bytes > INT_MAX) {
         return -EIO;
     }
 
@@ -1122,7 +1122,7 @@ static int blk_check_byte_request(BlockBackend *blk, int64_t offset,
         return -ENOMEDIUM;
     }
 
-    if (offset < 0) {
+    if (offset < 0 || bytes < 0) {
         return -EIO;
     }
 
@@ -1132,7 +1132,7 @@ static int blk_check_byte_request(BlockBackend *blk, int64_t offset,
             return len;
         }
 
-        if (offset > len || len - offset < size) {
+        if (offset > len || len - offset < bytes) {
             return -EIO;
         }
     }
@@ -1154,7 +1154,7 @@ static void coroutine_fn blk_wait_while_drained(BlockBackend *blk)
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
 static int coroutine_fn
-blk_do_preadv(BlockBackend *blk, int64_t offset, unsigned int bytes,
+blk_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
               QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     int ret;
@@ -1185,7 +1185,7 @@ blk_do_preadv(BlockBackend *blk, int64_t offset, unsigned int bytes,
 }
 
 int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
-                               unsigned int bytes, QEMUIOVector *qiov,
+                               int64_t bytes, QEMUIOVector *qiov,
                                BdrvRequestFlags flags)
 {
     int ret;
@@ -1199,7 +1199,7 @@ int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
 static int coroutine_fn
-blk_do_pwritev_part(BlockBackend *blk, int64_t offset, unsigned int bytes,
+blk_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes,
                     QEMUIOVector *qiov, size_t qiov_offset,
                     BdrvRequestFlags flags)
 {
@@ -1235,7 +1235,7 @@ blk_do_pwritev_part(BlockBackend *blk, int64_t offset, unsigned int bytes,
 }
 
 int coroutine_fn blk_co_pwritev_part(BlockBackend *blk, int64_t offset,
-                                     unsigned int bytes,
+                                     int64_t bytes,
                                      QEMUIOVector *qiov, size_t qiov_offset,
                                      BdrvRequestFlags flags)
 {
@@ -1249,7 +1249,7 @@ int coroutine_fn blk_co_pwritev_part(BlockBackend *blk, int64_t offset,
 }
 
 int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
-                                unsigned int bytes, QEMUIOVector *qiov,
+                                int64_t bytes, QEMUIOVector *qiov,
                                 BdrvRequestFlags flags)
 {
     return blk_co_pwritev_part(blk, offset, bytes, qiov, 0, flags);
@@ -1311,7 +1311,7 @@ static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf,
 }
 
 int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
-                      int bytes, BdrvRequestFlags flags)
+                      int64_t bytes, BdrvRequestFlags flags)
 {
     return blk_prw(blk, offset, NULL, bytes, blk_write_entry,
                    flags | BDRV_REQ_ZERO_WRITE);
@@ -1361,7 +1361,7 @@ BlockAIOCB *blk_abort_aio_request(BlockBackend *blk,
 typedef struct BlkAioEmAIOCB {
     BlockAIOCB common;
     BlkRwCo rwco;
-    int bytes;
+    int64_t bytes;
     bool has_returned;
 } BlkAioEmAIOCB;
 
@@ -1385,7 +1385,8 @@ static void blk_aio_complete_bh(void *opaque)
     blk_aio_complete(acb);
 }
 
-static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
+static BlockAIOCB *blk_aio_prwv(BlockBackend *blk,
+                                int64_t offset, int64_t bytes,
                                 void *iobuf, CoroutineEntry co_entry,
                                 BdrvRequestFlags flags,
                                 BlockCompletionFunc *cb, void *opaque)
@@ -1442,31 +1443,31 @@ static void blk_aio_write_entry(void *opaque)
 }
 
 BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
-                                  int count, BdrvRequestFlags flags,
+                                  int64_t bytes, BdrvRequestFlags flags,
                                   BlockCompletionFunc *cb, void *opaque)
 {
-    return blk_aio_prwv(blk, offset, count, NULL, blk_aio_write_entry,
+    return blk_aio_prwv(blk, offset, bytes, NULL, blk_aio_write_entry,
                         flags | BDRV_REQ_ZERO_WRITE, cb, opaque);
 }
 
-int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int count)
+int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int64_t bytes)
 {
-    int ret = blk_prw(blk, offset, buf, count, blk_read_entry, 0);
+    int ret = blk_prw(blk, offset, buf, bytes, blk_read_entry, 0);
     if (ret < 0) {
         return ret;
     }
-    return count;
+    return bytes;
 }
 
-int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int count,
-               BdrvRequestFlags flags)
+int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf,
+               int64_t bytes, BdrvRequestFlags flags)
 {
-    int ret = blk_prw(blk, offset, (void *) buf, count, blk_write_entry,
+    int ret = blk_prw(blk, offset, (void *) buf, bytes, blk_write_entry,
                       flags);
     if (ret < 0) {
         return ret;
     }
-    return count;
+    return bytes;
 }
 
 int64_t blk_getlength(BlockBackend *blk)
@@ -1567,7 +1568,7 @@ BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
 static int coroutine_fn
-blk_do_pdiscard(BlockBackend *blk, int64_t offset, int bytes)
+blk_do_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes)
 {
     int ret;
 
@@ -1591,14 +1592,15 @@ static void blk_aio_pdiscard_entry(void *opaque)
 }
 
 BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk,
-                             int64_t offset, int bytes,
+                             int64_t offset, int64_t bytes,
                              BlockCompletionFunc *cb, void *opaque)
 {
     return blk_aio_prwv(blk, offset, bytes, NULL, blk_aio_pdiscard_entry, 0,
                         cb, opaque);
 }
 
-int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset, int bytes)
+int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset,
+                                 int64_t bytes)
 {
     int ret;
 
@@ -1618,7 +1620,7 @@ static void blk_pdiscard_entry(void *opaque)
     aio_wait_kick();
 }
 
-int blk_pdiscard(BlockBackend *blk, int64_t offset, int bytes)
+int blk_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes)
 {
     return blk_prw(blk, offset, NULL, bytes, blk_pdiscard_entry, 0);
 }
@@ -2123,16 +2125,16 @@ void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
 }
 
 int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
-                                      int bytes, BdrvRequestFlags flags)
+                                      int64_t bytes, BdrvRequestFlags flags)
 {
     return blk_co_pwritev(blk, offset, bytes, NULL,
                           flags | BDRV_REQ_ZERO_WRITE);
 }
 
 int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
-                          int count)
+                          int64_t bytes)
 {
-    return blk_prw(blk, offset, (void *) buf, count, blk_write_entry,
+    return blk_prw(blk, offset, (void *) buf, bytes, blk_write_entry,
                    BDRV_REQ_WRITE_COMPRESSED);
 }
 
@@ -2358,7 +2360,7 @@ void blk_unregister_buf(BlockBackend *blk, void *host)
 
 int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
                                    BlockBackend *blk_out, int64_t off_out,
-                                   int bytes, BdrvRequestFlags read_flags,
+                                   int64_t bytes, BdrvRequestFlags read_flags,
                                    BdrvRequestFlags write_flags)
 {
     int r;
