[libvirt] [PATCH RFC] storage: Remove 'cow' disk format

[Peter Krempa]

There's no tests for this format and nothing seems to specifically care
about this format. QEMU does not even recognize it. Remove it completely.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 docs/schemas/storagecommon.rng |  1 -
 src/util/virstoragefile.c      | 31 +------------------------------
 src/util/virstoragefile.h      |  3 +--
 3 files changed, 2 insertions(+), 33 deletions(-)

diff --git a/docs/schemas/storagecommon.rng b/docs/schemas/storagecommon.rng
index edee1b0845..310ed758ff 100644
--- a/docs/schemas/storagecommon.rng
+++ b/docs/schemas/storagecommon.rng
@@ -78,7 +78,6 @@
        we know how to follow backing chains, and all others -->
   <define name='storageFormatBacking'>
     <choice>
-      <value>cow</value>
       <value>qcow</value>
       <value>qcow2</value>
       <value>qed</value>
diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index 67b9ec71ac..dd07f09d2c 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -67,7 +67,7 @@ VIR_ENUM_IMPL(virStorageFileFormat,
               /* Not direct file formats, but used for various drivers */
               "fat", "vhd", "ploop",
               /* Formats with backing file below here */
-              "cow", "qcow", "qcow2", "qed", "vmdk")
+              "qcow", "qcow2", "qed", "vmdk")

 VIR_ENUM_IMPL(virStorageFileFeature,
               VIR_STORAGE_FILE_FEATURE_LAST,
@@ -170,8 +170,6 @@ struct FileTypeInfo {
 };


-static int cowGetBackingStore(char **, int *,
-                              const char *, size_t);
 static int qcow1GetBackingStore(char **, int *,
                                 const char *, size_t);
 static int qcow2GetBackingStore(char **, int *,
@@ -348,11 +346,6 @@ static struct FileTypeInfo const fileTypeInfo[] = {
                                  PLOOP_SIZE_MULTIPLIER, NULL, NULL, NULL },

     /* All formats with a backing store probe below here */
-    [VIR_STORAGE_FILE_COW] = {
-        0, "OOOM", NULL,
-        LV_BIG_ENDIAN, 4, 4, {2},
-        4+4+1024+4, 8, 1, NULL, cowGetBackingStore, NULL
-    },
     [VIR_STORAGE_FILE_QCOW] = {
         0, "QFI", NULL,
         LV_BIG_ENDIAN, 4, 4, {1},
@@ -397,28 +390,6 @@ static const int qcow2CompatibleFeatureArray[] = {
 verify(ARRAY_CARDINALITY(qcow2CompatibleFeatureArray) ==
        QCOW2_COMPATIBLE_FEATURE_LAST);

-static int
-cowGetBackingStore(char **res,
-                   int *format,
-                   const char *buf,
-                   size_t buf_size)
-{
-#define COW_FILENAME_MAXLEN 1024
-    *res = NULL;
-    *format = VIR_STORAGE_FILE_AUTO;
-
-    if (buf_size < 4+4+ COW_FILENAME_MAXLEN)
-        return BACKING_STORE_INVALID;
-    if (buf[4+4] == '\0') { /* cow_header_v2.backing_file[0] */
-        *format = VIR_STORAGE_FILE_NONE;
-        return BACKING_STORE_OK;
-    }
-
-    if (VIR_STRNDUP(*res, (const char*)buf + 4 + 4, COW_FILENAME_MAXLEN) < 0)
-        return BACKING_STORE_ERROR;
-    return BACKING_STORE_OK;
-}
-

 static int
 qcow2GetBackingStoreFormat(int *format,
diff --git a/src/util/virstoragefile.h b/src/util/virstoragefile.h
index 596746ccb7..c84e013f46 100644
--- a/src/util/virstoragefile.h
+++ b/src/util/virstoragefile.h
@@ -82,8 +82,7 @@ typedef enum {
      * libvirt support for following a backing chain */
     VIR_STORAGE_FILE_BACKING,

-    VIR_STORAGE_FILE_COW = VIR_STORAGE_FILE_BACKING,
-    VIR_STORAGE_FILE_QCOW,
+    VIR_STORAGE_FILE_QCOW = VIR_STORAGE_FILE_BACKING,
     VIR_STORAGE_FILE_QCOW2,
     VIR_STORAGE_FILE_QED,
     VIR_STORAGE_FILE_VMDK,
-- 
2.16.2