block: Unlink temporary files in raw-posix/win32

Instead of having unlink() calls in the generic block layer, where we
aren't even guarateed to have a file name, move them to those block
drivers that are actually used and that always have a filename. Gets us
rid of some #ifdefs as well.

The patch also converts bs->is_temporary to a new BDRV_O_TEMPORARY open
flag so that it is inherited in the protocol layer and the raw-posix and
raw-win32 drivers can unlink the file.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

block.c

@@ -808,7 +808,7 @@ static int bdrv_backing_flags(int flags)
     flags &= ~(BDRV_O_RDWR | BDRV_O_COPY_ON_READ);
 
     /* snapshot=on is handled on the top layer */
-    flags &= ~BDRV_O_SNAPSHOT;
+    flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
 
     return flags;
 }
@@ -831,7 +831,7 @@ static int bdrv_open_flags(BlockDriverState *bs, int flags)
     /*
      * Snapshots should be writable.
      */
-    if (bs->is_temporary) {
+    if (flags & BDRV_O_TEMPORARY) {
         open_flags |= BDRV_O_RDWR;
     }
 
@@ -990,13 +990,6 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
     bdrv_refresh_limits(bs);
     assert(bdrv_opt_mem_align(bs) != 0);
     assert((bs->request_alignment != 0) || bs->sg);
-
-#ifndef _WIN32
-    if (bs->is_temporary) {
-        assert(bs->filename[0] != '\0');
-        unlink(bs->filename);
-    }
-#endif
     return 0;
 
 free_and_fail:
@@ -1267,10 +1260,10 @@ void bdrv_append_temp_snapshot(BlockDriverState *bs, Error **errp)
               qstring_from_str(tmp_filename));
 
     bs_snapshot = bdrv_new("", &error_abort);
-    bs_snapshot->is_temporary = 1;
 
     ret = bdrv_open(&bs_snapshot, NULL, NULL, snapshot_options,
-                    bs->open_flags & ~BDRV_O_SNAPSHOT, bdrv_qcow2, &local_err);
+                    (bs->open_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY,
+                    bdrv_qcow2, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
         goto out;
@@ -1371,7 +1364,7 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
                           bdrv_inherited_flags(flags),
                           true, &local_err);
     if (ret < 0) {
-        goto unlink_and_fail;
+        goto fail;
     }
 
     /* Find the right image format driver */
@@ -1382,7 +1375,7 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
         if (!drv) {
             error_setg(errp, "Invalid driver: '%s'", drvname);
             ret = -EINVAL;
-            goto unlink_and_fail;
+            goto fail;
         }
     }
 
@@ -1392,18 +1385,18 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
         } else {
             error_setg(errp, "Must specify either driver or file");
             ret = -EINVAL;
-            goto unlink_and_fail;
+            goto fail;
         }
     }
 
     if (!drv) {
-        goto unlink_and_fail;
+        goto fail;
     }
 
     /* Open the image */
     ret = bdrv_open_common(bs, file, options, flags, drv, &local_err);
     if (ret < 0) {
-        goto unlink_and_fail;
+        goto fail;
     }
 
     if (file && (bs->file != file)) {
@@ -1465,14 +1458,10 @@ done:
     *pbs = bs;
     return 0;
 
-unlink_and_fail:
+fail:
     if (file != NULL) {
         bdrv_unref(file);
     }
-    if (bs->is_temporary) {
-        unlink(filename);
-    }
-fail:
     QDECREF(bs->options);
     QDECREF(options);
     bs->options = NULL;
@@ -1752,11 +1741,6 @@ void bdrv_close(BlockDriverState *bs)
         }
         bs->drv->bdrv_close(bs);
         g_free(bs->opaque);
-#ifdef _WIN32
-        if (bs->is_temporary) {
-            unlink(bs->filename);
-        }
-#endif
         bs->opaque = NULL;
         bs->drv = NULL;
         bs->copy_on_read = 0;

block/raw-posix.c

@@ -366,7 +366,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     BDRVRawState *s = bs->opaque;
     QemuOpts *opts;
     Error *local_err = NULL;
-    const char *filename;
+    const char *filename = NULL;
     int fd, ret;
     struct stat st;
 
@@ -446,6 +446,9 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
 
     ret = 0;
 fail:
+    if (filename && (bdrv_flags & BDRV_O_TEMPORARY)) {
+        unlink(filename);
+    }
     qemu_opts_del(opts);
     return ret;
 }

block/raw-win32.c

@@ -390,6 +390,9 @@ static void raw_close(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
     CloseHandle(s->hfile);
+    if (bs->open_flags & BDRV_O_TEMPORARY) {
+        unlink(bs->filename);
+    }
 }
 
 static int raw_truncate(BlockDriverState *bs, int64_t offset)

include/block/block.h

@@ -92,6 +92,7 @@ typedef enum {
 
 #define BDRV_O_RDWR        0x0002
 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
+#define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
 #define BDRV_O_CACHE_WB    0x0040 /* use write-back caching */
 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */

include/block/block_int.h

@@ -299,7 +299,6 @@ struct BlockDriverState {
     char backing_file[1024]; /* if non zero, the image is a diff of
                                 this file image */
     char backing_format[16]; /* if non-zero and backing_file exists */
-    int is_temporary;
 
     BlockDriverState *backing_hd;
     BlockDriverState *file;