block: Make bdrv_{pread,pwrite}() return 0 on success
They currently return the value of their 'bytes' parameter on success.
Make them return 0 instead, for consistency with other I/O functions and
in preparation to implement them using generated_co_wrapper. This also
makes it clear that short reads/writes are not possible.
The few callers that rely on the previous behavior are adjusted
accordingly by hand.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220609152744.3891847-4-afaria@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
diff --git a/block/cloop.c b/block/cloop.c
index 9a23344..40b146e 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -222,7 +222,7 @@
ret = bdrv_pread(bs->file, s->offsets[block_num], bytes,
s->compressed_block, 0);
- if (ret != bytes) {
+ if (ret < 0) {
return -1;
}
diff --git a/block/crypto.c b/block/crypto.c
index deec7fa..e7f5c4e 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -70,7 +70,7 @@
error_setg_errno(errp, -ret, "Could not read encryption header");
return ret;
}
- return ret;
+ return buflen;
}
static ssize_t block_crypto_write_func(QCryptoBlock *block,
@@ -88,7 +88,7 @@
error_setg_errno(errp, -ret, "Could not write encryption header");
return ret;
}
- return ret;
+ return buflen;
}
diff --git a/block/dmg.c b/block/dmg.c
index 5a460c3..98db18d 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -390,7 +390,7 @@
buffer = g_malloc(info_length + 1);
buffer[info_length] = '\0';
ret = bdrv_pread(bs->file, info_begin, info_length, buffer, 0);
- if (ret != info_length) {
+ if (ret < 0) {
ret = -EINVAL;
goto fail;
}
@@ -611,7 +611,7 @@
* inflated. */
ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
s->compressed_chunk, 0);
- if (ret != s->lengths[chunk]) {
+ if (ret < 0) {
return -1;
}
@@ -637,7 +637,7 @@
* inflated. */
ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
s->compressed_chunk, 0);
- if (ret != s->lengths[chunk]) {
+ if (ret < 0) {
return -1;
}
@@ -658,7 +658,7 @@
* inflated. */
ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
s->compressed_chunk, 0);
- if (ret != s->lengths[chunk]) {
+ if (ret < 0) {
return -1;
}
@@ -674,7 +674,7 @@
case UDRW: /* copy */
ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
s->uncompressed_chunk, 0);
- if (ret != s->lengths[chunk]) {
+ if (ret < 0) {
return -1;
}
break;
diff --git a/block/io.c b/block/io.c
index d4a39b5..86b5e8b 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1100,7 +1100,6 @@
int bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf,
BdrvRequestFlags flags)
{
- int ret;
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
IO_CODE();
@@ -1108,9 +1107,7 @@
return -EINVAL;
}
- ret = bdrv_preadv(child, offset, bytes, &qiov, flags);
-
- return ret < 0 ? ret : bytes;
+ return bdrv_preadv(child, offset, bytes, &qiov, flags);
}
/* Return no. of bytes on success or < 0 on error. Important errors are:
@@ -1122,7 +1119,6 @@
int bdrv_pwrite(BdrvChild *child, int64_t offset, int64_t bytes,
const void *buf, BdrvRequestFlags flags)
{
- int ret;
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
IO_CODE();
@@ -1130,9 +1126,7 @@
return -EINVAL;
}
- ret = bdrv_pwritev(child, offset, bytes, &qiov, flags);
-
- return ret < 0 ? ret : bytes;
+ return bdrv_pwritev(child, offset, bytes, &qiov, flags);
}
/*
diff --git a/block/qcow.c b/block/qcow.c
index c94524b..c646d6b 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -597,7 +597,7 @@
csize &= (s->cluster_size - 1);
BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
ret = bdrv_pread(bs->file, coffset, csize, s->cluster_data, 0);
- if (ret != csize)
+ if (ret < 0)
return -1;
if (decompress_buffer(s->cluster_cache, s->cluster_size,
s->cluster_data, csize) < 0) {
diff --git a/block/qcow2.c b/block/qcow2.c
index 5493e6b..d5a1e8b 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -113,7 +113,7 @@
error_setg_errno(errp, -ret, "Could not read encryption header");
return -1;
}
- return ret;
+ return buflen;
}
@@ -174,7 +174,7 @@
error_setg_errno(errp, -ret, "Could not read encryption header");
return -1;
}
- return ret;
+ return buflen;
}
static QDict*
diff --git a/block/qed.c b/block/qed.c
index ba93e99..55da91e 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -87,14 +87,9 @@
int qed_write_header_sync(BDRVQEDState *s)
{
QEDHeader le;
- int ret;
qed_header_cpu_to_le(&s->header, &le);
- ret = bdrv_pwrite(s->bs->file, 0, sizeof(le), &le, 0);
- if (ret != sizeof(le)) {
- return ret;
- }
- return 0;
+ return bdrv_pwrite(s->bs->file, 0, sizeof(le), &le, 0);
}
/**
diff --git a/block/vdi.c b/block/vdi.c
index 9ef55a1..a0be2a2 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -730,7 +730,7 @@
n_sectors * SECTOR_SIZE, base, 0);
}
- return ret < 0 ? ret : 0;
+ return ret;
}
static int coroutine_fn vdi_co_do_create(BlockdevCreateOptions *create_options,
diff --git a/block/vmdk.c b/block/vmdk.c
index aacea10..332565c 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -473,7 +473,6 @@
if (ret < 0) {
goto out;
}
- ret = 0;
p_name = strstr(desc, "parentFileNameHint");
if (p_name != NULL) {
@@ -905,7 +904,7 @@
g_free(buf);
return NULL;
}
- buf[ret] = 0;
+ buf[size] = 0;
return buf;
}
@@ -1630,7 +1629,7 @@
l2_size_bytes,
l2_table,
0
- ) != l2_size_bytes) {
+ ) < 0) {
return VMDK_ERROR;
}
diff --git a/tests/unit/test-block-iothread.c b/tests/unit/test-block-iothread.c
index 49fb1ef..a5c163a 100644
--- a/tests/unit/test-block-iothread.c
+++ b/tests/unit/test-block-iothread.c
@@ -89,7 +89,7 @@
/* Success */
ret = bdrv_pread(c, 0, sizeof(buf), buf, 0);
- g_assert_cmpint(ret, ==, 512);
+ g_assert_cmpint(ret, ==, 0);
/* Early error: Negative offset */
ret = bdrv_pread(c, -2, sizeof(buf), buf, 0);
@@ -103,7 +103,7 @@
/* Success */
ret = bdrv_pwrite(c, 0, sizeof(buf), buf, 0);
- g_assert_cmpint(ret, ==, 512);
+ g_assert_cmpint(ret, ==, 0);
/* Early error: Negative offset */
ret = bdrv_pwrite(c, -2, sizeof(buf), buf, 0);
