[Qemu-block] [PATCH for-2.10 3/3] block: Add some bdrv_truncate() error messages

[Max Reitz]

Add missing error messages for the drivers I am comfortable to do this
in.

Signed-off-by: Max Reitz <address@hidden>
---
 block/file-posix.c | 8 +++++++-
 block/qcow2.c      | 2 ++
 block/qed.c        | 4 +++-
 block/raw-format.c | 2 ++
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 9d2bea730d..553213221c 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1341,20 +1341,26 @@ static int raw_truncate(BlockDriverState *bs, int64_t 
offset, Error **errp)
 {
     BDRVRawState *s = bs->opaque;
     struct stat st;
+    int ret;
 
     if (fstat(s->fd, &st)) {
-        return -errno;
+        ret = -errno;
+        error_setg_errno(errp, -ret, "Failed to fstat() the file");
+        return ret;
     }
 
     if (S_ISREG(st.st_mode)) {
         if (ftruncate(s->fd, offset) < 0) {
+            /* The generic error message will be fine */
             return -errno;
         }
     } else if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
        if (offset > raw_getlength(bs)) {
+           error_setg(errp, "Cannot grow device files");
            return -EINVAL;
        }
     } else {
+        error_setg(errp, "Resizing this file is not supported");
         return -ENOTSUP;
     }
 
diff --git a/block/qcow2.c b/block/qcow2.c
index 17585fbb89..53b0bd61a7 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2550,6 +2550,7 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t 
offset, Error **errp)
     new_l1_size = size_to_l1(s, offset);
     ret = qcow2_grow_l1_table(bs, new_l1_size, true);
     if (ret < 0) {
+        error_setg(errp, "Failed to grow the L1 table");
         return ret;
     }
 
@@ -2558,6 +2559,7 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t 
offset, Error **errp)
     ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
                            &offset, sizeof(uint64_t));
     if (ret < 0) {
+        error_setg(errp, "Failed to update the image size");
         return ret;
     }
 
diff --git a/block/qed.c b/block/qed.c
index fa2aeee471..eb346d645b 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1526,11 +1526,12 @@ static int bdrv_qed_truncate(BlockDriverState *bs, 
int64_t offset, Error **errp)
 
     if (!qed_is_image_size_valid(offset, s->header.cluster_size,
                                  s->header.table_size)) {
+        error_setg(errp, "Invalid image size specified");
         return -EINVAL;
     }
 
-    /* Shrinking is currently not supported */
     if ((uint64_t)offset < s->header.image_size) {
+        error_setg(errp, "Shrinking images is currently not supported");
         return -ENOTSUP;
     }
 
@@ -1539,6 +1540,7 @@ static int bdrv_qed_truncate(BlockDriverState *bs, 
int64_t offset, Error **errp)
     ret = qed_write_header_sync(s);
     if (ret < 0) {
         s->header.image_size = old_image_size;
+        error_setg(errp, "Failed to update the image size");
     }
     return ret;
 }
diff --git a/block/raw-format.c b/block/raw-format.c
index 9761bdaff8..36e65036f0 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -332,10 +332,12 @@ static int raw_truncate(BlockDriverState *bs, int64_t 
offset, Error **errp)
     BDRVRawState *s = bs->opaque;
 
     if (s->has_size) {
+        error_setg(errp, "Cannot resize fixed-size raw disks");
         return -ENOTSUP;
     }
 
     if (INT64_MAX - offset < s->offset) {
+        error_setg(errp, "Disk size too large for the chosen offset");
         return -EINVAL;
     }
 
-- 
2.12.0