Revert "qemu-img info: show nocow info"

This reverts commit 000c4dff.

The main reason for reverting this commit before the 2.2 release is that
it adds a QAPI interface that we don't want to keep: The 'nocow' flag
doesn't generally make sense for block nodes, but only for the raw-posix
driver. It should therefore be part of ImageInfoSpecific rather than
ImageInfo.

The commit contains more problems, but unlike the API stability issue
they wouldn't justify reverting it.

Conflicts:
	block/qapi.c
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

block/qapi.c

@@ -29,13 +29,6 @@
 #include "qapi/qmp-output-visitor.h"
 #include "qapi/qmp/types.h"
 #include "sysemu/block-backend.h"
-#ifdef __linux__
-#include <linux/fs.h>
-#include <sys/ioctl.h>
-#ifndef FS_NOCOW_FL
-#define FS_NOCOW_FL                     0x00800000 /* Do not cow file */
-#endif
-#endif
 
 BlockDeviceInfo *bdrv_block_device_info(BlockDriverState *bs)
 {
@@ -180,9 +173,6 @@ void bdrv_query_image_info(BlockDriverState *bs,
     int ret;
     Error *err = NULL;
     ImageInfo *info;
-#ifdef __linux__
-    int fd, attr;
-#endif
 
     size = bdrv_getlength(bs);
     if (size < 0) {
@@ -212,18 +202,6 @@ void bdrv_query_image_info(BlockDriverState *bs,
     info->format_specific     = bdrv_get_specific_info(bs);
     info->has_format_specific = info->format_specific != NULL;
 
-#ifdef __linux__
-    /* get NOCOW info */
-    fd = qemu_open(bs->filename, O_RDONLY | O_NONBLOCK);
-    if (fd >= 0) {
-        if (ioctl(fd, FS_IOC_GETFLAGS, &attr) == 0 && (attr & FS_NOCOW_FL)) {
-            info->has_nocow = true;
-            info->nocow = true;
-        }
-        qemu_close(fd);
-    }
-#endif
-
     backing_filename = bs->backing_file;
     if (backing_filename[0] != '\0') {
         info->backing_filename = g_strdup(backing_filename);
@@ -655,8 +633,4 @@ void bdrv_image_info_dump(fprintf_function func_fprintf, void *f,
         func_fprintf(f, "Format specific information:\n");
         bdrv_image_info_specific_dump(func_fprintf, f, info->format_specific);
     }
-
-    if (info->has_nocow && info->nocow) {
-        func_fprintf(f, "NOCOW flag: set\n");
-    }
 }

qapi/block-core.json

@@ -119,8 +119,6 @@
 # @format-specific: #optional structure supplying additional format-specific
 # information (since 1.7)
 #
-# @nocow: #optional info of whether NOCOW flag is set or not. (since 2.2)
-#
 # Since: 1.3
 #
 ##
@@ -132,8 +130,7 @@
            '*backing-filename': 'str', '*full-backing-filename': 'str',
            '*backing-filename-format': 'str', '*snapshots': ['SnapshotInfo'],
            '*backing-image': 'ImageInfo',
-           '*format-specific': 'ImageInfoSpecific',
-           '*nocow': 'bool' } }
+           '*format-specific': 'ImageInfoSpecific' } }
 
 ##
 # @ImageCheck: