From fdfeb0ba7b45b821c23fd3bd21f386d93dea6296 Mon Sep 17 00:00:00 2001 From: Colin Walters Date: Tue, 1 Oct 2024 17:07:17 -0400 Subject: [PATCH] checkout: Add commentary around whiteout "quoting" Signed-off-by: Colin Walters --- src/libostree/ostree-repo-checkout.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/src/libostree/ostree-repo-checkout.c b/src/libostree/ostree-repo-checkout.c index 39ecc1d59b..e83713d8ce 100644 --- a/src/libostree/ostree-repo-checkout.c +++ b/src/libostree/ostree-repo-checkout.c @@ -35,7 +35,13 @@ #define WHITEOUT_PREFIX ".wh." #define OPAQUE_WHITEOUT_NAME ".wh..wh..opq" -#define OVERLAYFS_WHITEOUT_PREFIX ".ostree-wh." +// ostree doesn't have native support for devices. Whiteouts in overlayfs +// are a 0:0 character device, and in some cases people are copying docker/podman +// style overlayfs container storage directly into ostree commits. This +// adds special support for "quoting" the whiteout so it just appears as a regular +// file in the ostree commit, but can be converted back into a character device +// on checkout. +#define OSTREE_QUOTED_OVERLAYFS_WHITEOUT_PREFIX ".ostree-wh." /* Per-checkout call state/caching */ typedef struct @@ -711,7 +717,8 @@ checkout_one_file_at (OstreeRepo *repo, OstreeRepoCheckoutAtOptions *options, Ch const gboolean is_whiteout = (!is_symlink && options->process_whiteouts && g_str_has_prefix (destination_name, WHITEOUT_PREFIX)); const gboolean is_overlayfs_whiteout - = (!is_symlink && g_str_has_prefix (destination_name, OVERLAYFS_WHITEOUT_PREFIX)); + = (!is_symlink + && g_str_has_prefix (destination_name, OSTREE_QUOTED_OVERLAYFS_WHITEOUT_PREFIX)); const gboolean is_reg_zerosized = (!is_symlink && g_file_info_get_size (source_info) == 0); const gboolean override_user_unreadable = (options->mode == OSTREE_REPO_CHECKOUT_MODE_USER && is_unreadable); @@ -735,7 +742,7 @@ checkout_one_file_at (OstreeRepo *repo, OstreeRepoCheckoutAtOptions *options, Ch } else if (is_overlayfs_whiteout && options->process_passthrough_whiteouts) { - const char *name = destination_name + (sizeof (OVERLAYFS_WHITEOUT_PREFIX) - 1); + const char *name = destination_name + (sizeof (OSTREE_QUOTED_OVERLAYFS_WHITEOUT_PREFIX) - 1); if (!name[0]) return glnx_throw (error, "Invalid empty overlayfs whiteout '%s'", name);