]> Git Repo - qemu.git/blobdiff - block.c
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[qemu.git] / block.c
diff --git a/block.c b/block.c
index a45b9b5c29b12a297e239f846ad4235cda68c752..fa1d06d84676f0f40c9119af8068f10d47d777f1 100644 (file)
--- a/block.c
+++ b/block.c
@@ -163,11 +163,16 @@ void path_combine(char *dest, int dest_size,
     if (path_is_absolute(filename)) {
         pstrcpy(dest, dest_size, filename);
     } else {
-        p = strchr(base_path, ':');
-        if (p)
-            p++;
-        else
-            p = base_path;
+        const char *protocol_stripped = NULL;
+
+        if (path_has_protocol(base_path)) {
+            protocol_stripped = strchr(base_path, ':');
+            if (protocol_stripped) {
+                protocol_stripped++;
+            }
+        }
+        p = protocol_stripped ?: base_path;
+
         p1 = strrchr(base_path, '/');
 #ifdef _WIN32
         {
@@ -192,11 +197,55 @@ void path_combine(char *dest, int dest_size,
     }
 }
 
+/*
+ * Helper function for bdrv_parse_filename() implementations to remove optional
+ * protocol prefixes (especially "file:") from a filename and for putting the
+ * stripped filename into the options QDict if there is such a prefix.
+ */
+void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix,
+                                      QDict *options)
+{
+    if (strstart(filename, prefix, &filename)) {
+        /* Stripping the explicit protocol prefix may result in a protocol
+         * prefix being (wrongly) detected (if the filename contains a colon) */
+        if (path_has_protocol(filename)) {
+            QString *fat_filename;
+
+            /* This means there is some colon before the first slash; therefore,
+             * this cannot be an absolute path */
+            assert(!path_is_absolute(filename));
+
+            /* And we can thus fix the protocol detection issue by prefixing it
+             * by "./" */
+            fat_filename = qstring_from_str("./");
+            qstring_append(fat_filename, filename);
+
+            assert(!path_has_protocol(qstring_get_str(fat_filename)));
+
+            qdict_put(options, "filename", fat_filename);
+        } else {
+            /* If no protocol prefix was detected, we can use the shortened
+             * filename as-is */
+            qdict_put_str(options, "filename", filename);
+        }
+    }
+}
+
+
+/* Returns whether the image file is opened as read-only. Note that this can
+ * return false and writing to the image file is still not possible because the
+ * image is inactivated. */
 bool bdrv_is_read_only(BlockDriverState *bs)
 {
     return bs->read_only;
 }
 
+/* Returns whether the image file can be written to right now */
+bool bdrv_is_writable(BlockDriverState *bs)
+{
+    return !bdrv_is_read_only(bs) && !(bs->open_flags & BDRV_O_INACTIVE);
+}
+
 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
 {
     /* Do not set read_only if copy_on_read is enabled */
@@ -762,6 +811,13 @@ static void bdrv_child_cb_drained_end(BdrvChild *child)
     bdrv_drained_end(bs);
 }
 
+static int bdrv_child_cb_inactivate(BdrvChild *child)
+{
+    BlockDriverState *bs = child->opaque;
+    assert(bs->open_flags & BDRV_O_INACTIVE);
+    return 0;
+}
+
 /*
  * Returns the options and flags that a temporary snapshot should get, based on
  * the originally requested flags (the originally requested image will have
@@ -800,6 +856,7 @@ static void bdrv_inherited_options(int *child_flags, QDict *child_options,
      * the parent. */
     qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
     qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
+    qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
 
     /* Inherit the read-only option from the parent if it's not set */
     qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
@@ -821,6 +878,7 @@ const BdrvChildRole child_file = {
     .inherit_options = bdrv_inherited_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_end     = bdrv_child_cb_drained_end,
+    .inactivate      = bdrv_child_cb_inactivate,
 };
 
 /*
@@ -842,6 +900,7 @@ const BdrvChildRole child_format = {
     .inherit_options = bdrv_inherited_fmt_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_end     = bdrv_child_cb_drained_end,
+    .inactivate      = bdrv_child_cb_inactivate,
 };
 
 static void bdrv_backing_attach(BdrvChild *c)
@@ -908,6 +967,7 @@ static void bdrv_backing_options(int *child_flags, QDict *child_options,
      * which is only applied on the top level (BlockBackend) */
     qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
     qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
+    qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
 
     /* backing files always opened read-only */
     qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
@@ -926,6 +986,7 @@ const BdrvChildRole child_backing = {
     .inherit_options = bdrv_backing_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_end     = bdrv_child_cb_drained_end,
+    .inactivate      = bdrv_child_cb_inactivate,
 };
 
 static int bdrv_open_flags(BlockDriverState *bs, int flags)
@@ -1150,6 +1211,11 @@ QemuOptsList bdrv_runtime_opts = {
             .type = QEMU_OPT_STRING,
             .help = "discard operation (ignore/off, unmap/on)",
         },
+        {
+            .name = BDRV_OPT_FORCE_SHARE,
+            .type = QEMU_OPT_BOOL,
+            .help = "always accept other writers (default: off)",
+        },
         { /* end of list */ }
     },
 };
@@ -1189,6 +1255,16 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
     drv = bdrv_find_format(driver_name);
     assert(drv != NULL);
 
+    bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false);
+
+    if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) {
+        error_setg(errp,
+                   BDRV_OPT_FORCE_SHARE
+                   "=on can only be used with read-only images");
+        ret = -EINVAL;
+        goto fail_opts;
+    }
+
     if (file != NULL) {
         filename = blk_bs(file)->filename;
     } else {
@@ -1448,6 +1524,22 @@ static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
 static void bdrv_child_abort_perm_update(BdrvChild *c);
 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared);
 
+static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
+                            BdrvChild *c,
+                            const BdrvChildRole *role,
+                            uint64_t parent_perm, uint64_t parent_shared,
+                            uint64_t *nperm, uint64_t *nshared)
+{
+    if (bs->drv && bs->drv->bdrv_child_perm) {
+        bs->drv->bdrv_child_perm(bs, c, role,
+                                 parent_perm, parent_shared,
+                                 nperm, nshared);
+    }
+    if (child_bs && child_bs->force_share) {
+        *nshared = BLK_PERM_ALL;
+    }
+}
+
 /*
  * Check whether permissions on this node can be changed in a way that
  * @cumulative_perms and @cumulative_shared_perms are the new cumulative
@@ -1467,7 +1559,7 @@ static int bdrv_check_perm(BlockDriverState *bs, uint64_t cumulative_perms,
 
     /* Write permissions never work with read-only images */
     if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
-        bdrv_is_read_only(bs))
+        !bdrv_is_writable(bs))
     {
         error_setg(errp, "Block node is read-only");
         return -EPERM;
@@ -1492,9 +1584,9 @@ static int bdrv_check_perm(BlockDriverState *bs, uint64_t cumulative_perms,
     /* Check all children */
     QLIST_FOREACH(c, &bs->children, next) {
         uint64_t cur_perm, cur_shared;
-        drv->bdrv_child_perm(bs, c, c->role,
-                             cumulative_perms, cumulative_shared_perms,
-                             &cur_perm, &cur_shared);
+        bdrv_child_perm(bs, c->bs, c, c->role,
+                        cumulative_perms, cumulative_shared_perms,
+                        &cur_perm, &cur_shared);
         ret = bdrv_child_check_perm(c, cur_perm, cur_shared, ignore_children,
                                     errp);
         if (ret < 0) {
@@ -1554,9 +1646,9 @@ static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
     /* Update all children */
     QLIST_FOREACH(c, &bs->children, next) {
         uint64_t cur_perm, cur_shared;
-        drv->bdrv_child_perm(bs, c, c->role,
-                             cumulative_perms, cumulative_shared_perms,
-                             &cur_perm, &cur_shared);
+        bdrv_child_perm(bs, c->bs, c, c->role,
+                        cumulative_perms, cumulative_shared_perms,
+                        &cur_perm, &cur_shared);
         bdrv_child_set_perm(c, cur_perm, cur_shared);
     }
 }
@@ -1586,7 +1678,7 @@ static char *bdrv_child_user_desc(BdrvChild *c)
     return g_strdup("another user");
 }
 
-static char *bdrv_perm_names(uint64_t perm)
+char *bdrv_perm_names(uint64_t perm)
 {
     struct perm_name {
         uint64_t perm;
@@ -1752,7 +1844,7 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
         bdrv_filter_default_perms(bs, c, role, perm, shared, &perm, &shared);
 
         /* Format drivers may touch metadata even if the guest doesn't write */
-        if (!bdrv_is_read_only(bs)) {
+        if (bdrv_is_writable(bs)) {
             perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
         }
 
@@ -1778,6 +1870,10 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
                   BLK_PERM_WRITE_UNCHANGED;
     }
 
+    if (bs->open_flags & BDRV_O_INACTIVE) {
+        shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+    }
+
     *nperm = perm;
     *nshared = shared;
 }
@@ -1891,8 +1987,8 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
 
     assert(parent_bs->drv);
     assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs));
-    parent_bs->drv->bdrv_child_perm(parent_bs, NULL, child_role,
-                                    perm, shared_perm, &perm, &shared_perm);
+    bdrv_child_perm(parent_bs, child_bs, NULL, child_role,
+                    perm, shared_perm, &perm, &shared_perm);
 
     child = bdrv_root_attach_child(child_bs, child_name, child_role,
                                    perm, shared_perm, parent_bs, errp);
@@ -3916,7 +4012,8 @@ void bdrv_init_with_whitelist(void)
 
 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
 {
-    BdrvChild *child;
+    BdrvChild *child, *parent;
+    uint64_t perm, shared_perm;
     Error *local_err = NULL;
     int ret;
 
@@ -3952,6 +4049,26 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
         error_setg_errno(errp, -ret, "Could not refresh total sector count");
         return;
     }
+
+    /* Update permissions, they may differ for inactive nodes */
+    bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
+    ret = bdrv_check_perm(bs, perm, shared_perm, NULL, &local_err);
+    if (ret < 0) {
+        bs->open_flags |= BDRV_O_INACTIVE;
+        error_propagate(errp, local_err);
+        return;
+    }
+    bdrv_set_perm(bs, perm, shared_perm);
+
+    QLIST_FOREACH(parent, &bs->parents, next_parent) {
+        if (parent->role->activate) {
+            parent->role->activate(parent, &local_err);
+            if (local_err) {
+                error_propagate(errp, local_err);
+                return;
+            }
+        }
+    }
 }
 
 void bdrv_invalidate_cache_all(Error **errp)
@@ -3976,7 +4093,7 @@ void bdrv_invalidate_cache_all(Error **errp)
 static int bdrv_inactivate_recurse(BlockDriverState *bs,
                                    bool setting_flag)
 {
-    BdrvChild *child;
+    BdrvChild *child, *parent;
     int ret;
 
     if (!setting_flag && bs->drv->bdrv_inactivate) {
@@ -3986,6 +4103,27 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs,
         }
     }
 
+    if (setting_flag) {
+        uint64_t perm, shared_perm;
+
+        bs->open_flags |= BDRV_O_INACTIVE;
+
+        QLIST_FOREACH(parent, &bs->parents, next_parent) {
+            if (parent->role->inactivate) {
+                ret = parent->role->inactivate(parent);
+                if (ret < 0) {
+                    bs->open_flags &= ~BDRV_O_INACTIVE;
+                    return ret;
+                }
+            }
+        }
+
+        /* Update permissions, they may differ for inactive nodes */
+        bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
+        bdrv_check_perm(bs, perm, shared_perm, NULL, &error_abort);
+        bdrv_set_perm(bs, perm, shared_perm);
+    }
+
     QLIST_FOREACH(child, &bs->children, next) {
         ret = bdrv_inactivate_recurse(child->bs, setting_flag);
         if (ret < 0) {
@@ -3993,9 +4131,6 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs,
         }
     }
 
-    if (setting_flag) {
-        bs->open_flags |= BDRV_O_INACTIVE;
-    }
     return 0;
 }
 
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