[Qemu-block] [PATCH v3 for-2.10 4/4] block: Add .bdrv_truncate() error messages

[Max Reitz]

Add missing error messages for the block driver implementations of
.bdrv_truncate(); drop the generic one from block.c's bdrv_truncate().

Since one of these changes touches a mis-indented block in
block/file-posix.c, this patch fixes that coding style issue along the
way.

Signed-off-by: Max Reitz <address@hidden>
---
 block.c            |  2 --
 block/file-posix.c | 17 ++++++++++++-----
 block/gluster.c    |  4 +++-
 block/iscsi.c      |  2 ++
 block/nfs.c        | 10 +++++++++-
 block/qcow2.c      |  2 ++
 block/qed.c        |  4 +++-
 block/raw-format.c |  2 ++
 block/rbd.c        |  1 +
 9 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/block.c b/block.c
index 7b9841f99a..80e16e33d3 100644
--- a/block.c
+++ b/block.c
@@ -3249,8 +3249,6 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, Error 
**errp)
         bdrv_dirty_bitmap_truncate(bs);
         bdrv_parent_cb_resize(bs);
         ++bs->write_gen;
-    } else if (errp && !*errp) {
-        error_setg_errno(errp, -ret, "Failed to resize image");
     }
     return ret;
 }
diff --git a/block/file-posix.c b/block/file-posix.c
index d23464013f..c08d031c78 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1413,20 +1413,27 @@ 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) {
-            return -errno;
+            ret = -errno;
+            error_setg_errno(errp, -ret, "Failed to resize the file");
+            return ret;
         }
     } else if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
-       if (offset > raw_getlength(bs)) {
-           return -EINVAL;
-       }
+        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/gluster.c b/block/gluster.c
index 00b8240562..65350b575b 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -1092,7 +1092,9 @@ static int qemu_gluster_truncate(BlockDriverState *bs, 
int64_t offset,
 
     ret = glfs_ftruncate(s->fd, offset);
     if (ret < 0) {
-        return -errno;
+        ret = -errno;
+        error_setg_errno(errp, -ret, "Failed to truncate file");
+        return ret;
     }
 
     return 0;
diff --git a/block/iscsi.c b/block/iscsi.c
index ab559a6f71..036f5b6930 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -2066,6 +2066,7 @@ static int iscsi_truncate(BlockDriverState *bs, int64_t 
offset, Error **errp)
     Error *local_err = NULL;
 
     if (iscsilun->type != TYPE_DISK) {
+        error_setg(errp, "Cannot resize non-disk iSCSI devices");
         return -ENOTSUP;
     }
 
@@ -2076,6 +2077,7 @@ static int iscsi_truncate(BlockDriverState *bs, int64_t 
offset, Error **errp)
     }
 
     if (offset > iscsi_getlength(bs)) {
+        error_setg(errp, "Cannot grow iSCSI devices");
         return -EINVAL;
     }
 
diff --git a/block/nfs.c b/block/nfs.c
index 57d12efc51..6eccf18d75 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -760,7 +760,15 @@ static int64_t 
nfs_get_allocated_file_size(BlockDriverState *bs)
 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset, Error 
**errp)
 {
     NFSClient *client = bs->opaque;
-    return nfs_ftruncate(client->context, client->fh, offset);
+    int ret;
+
+    ret = nfs_ftruncate(client->context, client->fh, offset);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to truncate file");
+        return ret;
+    }
+
+    return 0;
 }
 
 /* Note that this will not re-establish a connection with the NFS server
diff --git a/block/qcow2.c b/block/qcow2.c
index 6c347989e3..4ca4cf04b0 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2551,6 +2551,7 @@ 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_errno(errp, -ret, "Failed to grow the L1 table");
         return ret;
     }
 
@@ -2559,6 +2560,7 @@ 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_errno(errp, -ret, "Failed to update the image size");
         return ret;
     }
 
diff --git a/block/qed.c b/block/qed.c
index fa2aeee471..fd76817cbb 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_errno(errp, -ret, "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;
     }
 
diff --git a/block/rbd.c b/block/rbd.c
index 30bb0b7798..1ea29f7a97 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -886,6 +886,7 @@ static int qemu_rbd_truncate(BlockDriverState *bs, int64_t 
offset, Error **errp)
 
     r = rbd_resize(s->image, offset);
     if (r < 0) {
+        error_setg_errno(errp, -r, "Failed to resize file");
         return r;
     }
 
-- 
2.12.1