[PULL 02/20] block: refactor bdrv_check_request: add errp

[Eric Blake <eblake@redhat.com>]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

It's better to pass &error_abort than just assert that result is 0: on
crash, we'll immediately see the reason in the backtrace.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201211183934.169161-2-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: fix iotest 206 fallout]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 include/block/block_int.h    |  2 +-
 block/io.c                   | 29 ++++++++++++++++++++++-------
 block/file-posix.c           |  2 +-
 tests/test-write-threshold.c |  5 +++--
 tests/qemu-iotests/206.out   |  2 +-
 5 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index d01fc2372028..5bbbf9ee0af9 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -93,7 +93,7 @@ typedef struct BdrvTrackedRequest {
     struct BdrvTrackedRequest *waiting_for;
 } BdrvTrackedRequest;

-int bdrv_check_request(int64_t offset, int64_t bytes);
+int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp);

 struct BlockDriver {
     const char *format_name;
diff --git a/block/io.c b/block/io.c
index d203435a73d6..23abdae79468 100644
--- a/block/io.c
+++ b/block/io.c
@@ -920,17 +920,34 @@ bool coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req,
     return waited;
 }

-int bdrv_check_request(int64_t offset, int64_t bytes)
+int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp)
 {
-    if (offset < 0 || bytes < 0) {
+    if (offset < 0) {
+        error_setg(errp, "offset is negative: %" PRIi64, offset);
+        return -EIO;
+    }
+
+    if (bytes < 0) {
+        error_setg(errp, "bytes is negative: %" PRIi64, bytes);
         return -EIO;
     }

     if (bytes > BDRV_MAX_LENGTH) {
+        error_setg(errp, "bytes(%" PRIi64 ") exceeds maximum(%" PRIi64 ")",
+                   bytes, BDRV_MAX_LENGTH);
+        return -EIO;
+    }
+
+    if (offset > BDRV_MAX_LENGTH) {
+        error_setg(errp, "offset(%" PRIi64 ") exceeds maximum(%" PRIi64 ")",
+                   offset, BDRV_MAX_LENGTH);
         return -EIO;
     }

     if (offset > BDRV_MAX_LENGTH - bytes) {
+        error_setg(errp, "sum of offset(%" PRIi64 ") and bytes(%" PRIi64 ") "
+                   "exceeds maximum(%" PRIi64 ")", offset, bytes,
+                   BDRV_MAX_LENGTH);
         return -EIO;
     }

@@ -939,7 +956,7 @@ int bdrv_check_request(int64_t offset, int64_t bytes)

 static int bdrv_check_request32(int64_t offset, int64_t bytes)
 {
-    int ret = bdrv_check_request(offset, bytes);
+    int ret = bdrv_check_request(offset, bytes, NULL);
     if (ret < 0) {
         return ret;
     }
@@ -2847,7 +2864,7 @@ int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset,
         return -EPERM;
     }

-    ret = bdrv_check_request(offset, bytes);
+    ret = bdrv_check_request(offset, bytes, NULL);
     if (ret < 0) {
         return ret;
     }
@@ -3249,10 +3266,8 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
         return -EINVAL;
     }

-    ret = bdrv_check_request(offset, 0);
+    ret = bdrv_check_request(offset, 0, errp);
     if (ret < 0) {
-        error_setg(errp, "Required too big image size, it must be not greater "
-                   "than %" PRId64, BDRV_MAX_LENGTH);
         return ret;
     }

diff --git a/block/file-posix.c b/block/file-posix.c
index 11aafa9d82b2..05079b40caee 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2969,7 +2969,7 @@ raw_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes,

         req->bytes = BDRV_MAX_LENGTH - req->offset;

-        assert(bdrv_check_request(req->offset, req->bytes) == 0);
+        bdrv_check_request(req->offset, req->bytes, &error_abort);

         bdrv_make_request_serialising(req, bs->bl.request_alignment);
     }
diff --git a/tests/test-write-threshold.c b/tests/test-write-threshold.c
index 4cf032652dfd..fc1c45a2eb95 100644
--- a/tests/test-write-threshold.c
+++ b/tests/test-write-threshold.c
@@ -7,6 +7,7 @@
  */

 #include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "block/block_int.h"
 #include "block/write-threshold.h"

@@ -64,7 +65,7 @@ static void test_threshold_not_trigger(void)
     req.offset = 1024;
     req.bytes = 1024;

-    assert(bdrv_check_request(req.offset, req.bytes) == 0);
+    bdrv_check_request(req.offset, req.bytes, &error_abort);

     bdrv_write_threshold_set(&bs, threshold);
     amount = bdrv_write_threshold_exceeded(&bs, &req);
@@ -84,7 +85,7 @@ static void test_threshold_trigger(void)
     req.offset = (4 * 1024 * 1024) - 1024;
     req.bytes = 2 * 1024;

-    assert(bdrv_check_request(req.offset, req.bytes) == 0);
+    bdrv_check_request(req.offset, req.bytes, &error_abort);

     bdrv_write_threshold_set(&bs, threshold);
     amount = bdrv_write_threshold_exceeded(&bs, &req);
diff --git a/tests/qemu-iotests/206.out b/tests/qemu-iotests/206.out
index e8a36de00bda..5dd589d14e47 100644
--- a/tests/qemu-iotests/206.out
+++ b/tests/qemu-iotests/206.out
@@ -180,7 +180,7 @@ Job failed: Could not resize image: Image size cannot be negative

 {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "qcow2", "file": "node0", "size": 9223372036854775296}}}
 {"return": {}}
-Job failed: Could not resize image: Required too big image size, it must be not greater than 9223372035781033984
+Job failed: Could not resize image: offset(9223372036854775296) exceeds maximum(9223372035781033984)
 {"execute": "job-dismiss", "arguments": {"id": "job0"}}
 {"return": {}}

-- 
2.30.0