mirror of
https://github.com/containers/fuse-overlayfs.git
synced 2025-09-09 07:16:11 -04:00
fuse-overlayfs: rename uses a .wh. style whiteout
during a rename, use a .wh. style whiteout for the destination, so that if the rename fails we don't make visible files from the lower layers. Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
This commit is contained in:
Giuseppe Scrivano
parent
e908a68156
commit
cc18f5ce18
173
main.c
173
main.c
@ -294,13 +294,13 @@ has_prefix (const char *str, const char *pref)
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}
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static int
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create_whiteout (struct ovl_data *lo, struct ovl_node *parent, const char *name)
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create_whiteout (struct ovl_data *lo, struct ovl_node *parent, const char *name, bool skip_mknod)
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{
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char whiteout_path[PATH_MAX + 10];
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int fd = -1;
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static bool can_mknod = true;
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if (can_mknod)
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if (!skip_mknod && can_mknod)
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{
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int ret;
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@ -338,23 +338,25 @@ delete_whiteout (struct ovl_data *lo, int dirfd, struct ovl_node *parent, const
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&& major (st.st_rdev) == 0
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&& minor (st.st_rdev) == 0)
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{
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return unlinkat (dirfd, name, 0);
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if (unlinkat (dirfd, name, 0) < 0)
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return -1;
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}
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}
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else
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{
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sprintf (whiteout_path, "%s/.wh.%s", parent->path, name);
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sprintf (whiteout_path, "%s/%s", parent->path, name);
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if (TEMP_FAILURE_RETRY (fstatat (get_upper_layer (lo)->fd, whiteout_path, &st, AT_SYMLINK_NOFOLLOW)) == 0
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&& (st.st_mode & S_IFMT) == S_IFCHR
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&& major (st.st_rdev) == 0
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&& minor (st.st_rdev) == 0)
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{
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return unlinkat (get_upper_layer (lo)->fd, whiteout_path, 0);
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if (unlinkat (get_upper_layer (lo)->fd, whiteout_path, 0) < 0)
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return -1;
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}
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}
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/* If the whiteout was not found, try the .wh. alternative used when running as non-root. */
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/* Look for the .wh. alternative as well. */
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if (dirfd >= 0)
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{
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@ -389,27 +391,9 @@ hide_node (struct ovl_data *lo, struct ovl_node *node, bool unlink_src)
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/* Might be leftover from a previous run. */
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unlinkat (lo->workdir_fd, newpath, 0);
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unlinkat (lo->workdir_fd, newpath, AT_REMOVEDIR);
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if (! unlink_src)
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{
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if (node_dirp (node))
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{
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if (renameat (node_dirfd (node), node->path, lo->workdir_fd, newpath) < 0)
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{
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free (newpath);
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return -1;
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}
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}
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else
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{
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if (linkat (node_dirfd (node), node->path, lo->workdir_fd, newpath, 0) < 0)
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{
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free (newpath);
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return -1;
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}
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}
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}
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else
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if (unlink_src)
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{
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/* If the atomic rename+mknod failed, then fallback into doing it in two steps. */
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if (syscall (SYS_renameat2, node_dirfd (node), node->path, lo->workdir_fd,
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@ -422,11 +406,30 @@ hide_node (struct ovl_data *lo, struct ovl_node *node, bool unlink_src)
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}
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if (node->parent)
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{
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if (create_whiteout (lo, node->parent, node->name) < 0)
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if (create_whiteout (lo, node->parent, node->name, false) < 0)
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return -1;
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}
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}
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}
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else
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{
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if (node_dirp (node))
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{
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if (mkdirat (lo->workdir_fd, newpath, 0700) < 0)
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{
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free (newpath);
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return -1;
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}
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}
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else
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{
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if (linkat (node_dirfd (node), node->path, lo->workdir_fd, newpath, 0) < 0)
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{
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free (newpath);
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return -1;
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}
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}
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}
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node->hidden_dirfd = lo->workdir_fd;
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free (node->path);
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node->path = newpath;
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@ -761,7 +764,7 @@ load_dir (struct ovl_data *lo, struct ovl_node *n, struct ovl_layer *layer, char
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DIR *dp;
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struct dirent *dent;
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struct stat st;
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struct ovl_layer *it;
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struct ovl_layer *it, *upper_layer = get_upper_layer (lo);
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if (!n)
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{
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@ -804,9 +807,19 @@ load_dir (struct ovl_data *lo, struct ovl_node *n, struct ovl_layer *layer, char
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child = hash_lookup (n->children, &key);
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if (child)
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{
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if (it->low)
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child->present_lowerdir = 1;
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continue;
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if (child->whiteout && it == upper_layer)
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{
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hash_delete (n->children, child);
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node_free (child);
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child = NULL;
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}
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else
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{
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if (it->low)
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child->present_lowerdir = 1;
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child->ino = st.st_ino;
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continue;
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}
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}
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sprintf (node_path, "%s/%s", n->path, dent->d_name);
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@ -940,6 +953,7 @@ do_lookup_file (struct ovl_data *lo, fuse_ino_t parent, const char *name)
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char path[PATH_MAX];
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struct ovl_layer *it;
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struct stat st;
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struct ovl_layer *upper_layer = get_upper_layer (lo);
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for (it = lo->layers; it; it = it->next)
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{
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@ -964,10 +978,19 @@ do_lookup_file (struct ovl_data *lo, fuse_ino_t parent, const char *name)
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/* If we already know the node, simply update the ino. */
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if (node)
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{
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node->ino = st.st_ino;
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if (it->low)
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node->present_lowerdir = 1;
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continue;
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if (node->whiteout && it == upper_layer)
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{
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hash_delete (pnode->children, node);
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node_free (node);
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node = NULL;
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}
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else
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{
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node->ino = st.st_ino;
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if (it->low)
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node->present_lowerdir = 1;
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continue;
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}
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}
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wh_name = get_whiteout_name (name, &st);
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@ -1185,7 +1208,7 @@ create_missing_whiteouts (struct ovl_data *lo, struct ovl_node *node, const char
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continue;
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}
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if (create_whiteout (lo, node, dent->d_name) < 0)
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if (create_whiteout (lo, node, dent->d_name, false) < 0)
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{
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closedir (dp);
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return -1;
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@ -1573,11 +1596,6 @@ copyup (struct ovl_data *lo, struct ovl_node *node)
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ret = create_node_directory (lo, node->parent);
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if (ret < 0)
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return ret;
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char whpath[PATH_MAX + 10];
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sprintf (whpath, "%s/.wh.%s", node->parent->path, node->name);
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if (unlinkat (get_upper_layer (lo)->fd, whpath, 0) < 0 && errno != ENOENT)
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goto exit;
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}
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if ((st.st_mode & S_IFMT) == S_IFDIR)
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@ -1654,6 +1672,14 @@ copyup (struct ovl_data *lo, struct ovl_node *node)
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if (ret < 0)
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goto exit;
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if (node->parent)
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{
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char whpath[PATH_MAX + 10];
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sprintf (whpath, "%s/.wh.%s", node->parent->path, node->name);
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if (unlinkat (get_upper_layer (lo)->fd, whpath, 0) < 0 && errno != ENOENT)
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goto exit;
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}
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success:
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ret = 0;
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@ -2705,7 +2731,7 @@ ovl_rename_direct (fuse_req_t req, fuse_ino_t parent, const char *name,
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struct ovl_node key;
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node = do_lookup_file (lo, parent, name);
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if (node == NULL)
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if (node == NULL || node->whiteout)
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{
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fuse_reply_err (req, ENOENT);
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return;
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@ -2762,41 +2788,31 @@ ovl_rename_direct (fuse_req_t req, fuse_ino_t parent, const char *name,
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goto error;
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}
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if (destnode != NULL && !destnode->whiteout && node_dirp (destnode))
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{
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size_t whiteouts = 0;
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destnode = load_dir (lo, destnode, destnode->layer, destnode->path, destnode->name);
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if (destnode == NULL)
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goto error;
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if (count_dir_entries (destnode, &whiteouts) > 0)
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{
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errno = ENOTEMPTY;
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goto error;
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}
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if (whiteouts && empty_dir (lo, destnode) < 0)
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goto error;
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if (create_missing_whiteouts (lo, node, destnode->path) < 0)
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{
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fuse_reply_err (req, errno);
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return;
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}
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}
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if (destnode)
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{
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size_t destnode_whiteouts = 0;
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if (!destnode->whiteout && destnode->ino == node->ino)
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goto error;
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if (node_dirp (node) && destnode->present_lowerdir)
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if (!destnode->whiteout && node_dirp (destnode))
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{
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if (create_missing_whiteouts (lo, node, destnode->path) < 0)
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destnode = load_dir (lo, destnode, destnode->layer, destnode->path, destnode->name);
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if (destnode == NULL)
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goto error;
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if (count_dir_entries (destnode, &destnode_whiteouts) > 0)
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{
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errno = ENOTEMPTY;
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goto error;
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}
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if (destnode_whiteouts && empty_dir (lo, destnode) < 0)
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goto error;
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}
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if (node_dirp (node) && create_missing_whiteouts (lo, node, destnode->path) < 0)
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goto error;
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if (destnode->lookups > 0)
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node_free (destnode);
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else
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@ -2822,7 +2838,16 @@ ovl_rename_direct (fuse_req_t req, fuse_ino_t parent, const char *name,
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}
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}
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unlinkat (destfd, newname, 0);
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/* If the node is a directory we must ensure there is no whiteout at the
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destination, otherwise the renameat2 will fail. Create a .wh.$NAME style
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whiteout file until the renameat2 is completed. */
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if (node_dirp (node))
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{
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ret = create_whiteout (lo, destpnode, newname, true);
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if (ret < 0)
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goto error;
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unlinkat (destfd, newname, 0);
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}
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/* Try to create the whiteout atomically, if it fails do the
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rename+mknod separately. */
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@ -2834,11 +2859,14 @@ ovl_rename_direct (fuse_req_t req, fuse_ino_t parent, const char *name,
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if (ret < 0)
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goto error;
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ret = create_whiteout (lo, pnode, name);
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ret = create_whiteout (lo, pnode, name, false);
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if (ret < 0)
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goto error;
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}
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if (delete_whiteout (lo, destfd, NULL, newname) < 0)
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goto error;
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hash_delete (pnode->children, node);
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free (node->name);
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@ -2855,9 +2883,6 @@ ovl_rename_direct (fuse_req_t req, fuse_ino_t parent, const char *name,
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if (update_paths (node) < 0)
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goto error;
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if (delete_whiteout (lo, destfd, NULL, newname) < 0)
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goto error;
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ret = 0;
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goto cleanup;
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@ -2964,7 +2989,7 @@ hide_all (struct ovl_data *lo, struct ovl_node *node)
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int ret;
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it = nodes[i];
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ret = create_whiteout (lo, node, it->name);
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ret = create_whiteout (lo, node, it->name, false);
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node_free (it);
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if (ret < 0)
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