From 6aae7985eb8ecb6faecb20376500f1026960a801 Mon Sep 17 00:00:00 2001

From: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>

Date: Mon, 4 Mar 2024 12:20:19 -0500

Subject: [PATCH] fall back to user ioctl for ino path lookup

---

 cmds/receive.c        |  2 +-

 cmds/subvolume-list.c | 48 +++++++++++++++++++++++++++++++++++++++++++

 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/cmds/receive.c b/cmds/receive.c

index e4430b07..051eca6a 100644

--- a/cmds/receive.c

+++ b/cmds/receive.c

@@ -1285,7 +1285,7 @@ static int process_encoded_write(const char *path, const void *data, u64 offset,

 		if (ret >= 0)

 			return 0;

 		/* Fall back for these errors, fail hard for anything else. */

-		if (errno != ENOSPC && errno != ENOTTY && errno != EINVAL) {

+		if (errno != ENOSPC && errno != ENOTTY && errno != EINVAL && errno != EPERM) {

 			ret = -errno;

 			error("encoded_write: writing to %s failed: %m", path);

 			return ret;

diff --git a/cmds/subvolume-list.c b/cmds/subvolume-list.c

index 5a91f41d..c3bc7b70 100644

--- a/cmds/subvolume-list.c

+++ b/cmds/subvolume-list.c

@@ -759,6 +759,49 @@ static int resolve_root(struct rb_root *rl, struct root_info *ri,

 	return 0;

 }

+/*

+ * as user, for a single root_info, ask the kernel to give us a path name

+ * inside it's ref_root for the dir_id where it lives.

+ *

+ * This fills in root_info->path with the path to the directory and and

+ * appends this root's name.

+ */

+static int lookup_ino_path_user(int fd, struct root_info *ri)

+{

+	struct btrfs_ioctl_ino_lookup_user_args args;

+	int ret;

+

+	if (ri->path)

+		return 0;

+

+	if (!ri->ref_tree)

+		return -ENOENT;

+

+	memset(&args, 0, sizeof(args));

+	args.treeid = ri->ref_tree;

+	args.dirid = ri->dir_id;

+

+	ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP_USER, &args);

+	if (ret < 0) {

+		if (errno == ENOENT) {

+			ri->ref_tree = 0;

+			return -ENOENT;

+		}

+		error("failed to lookup path for root %llu: %m", ri->ref_tree);

+		return ret;

+	}

+

+	ri->path = malloc(strlen(args.name) + strlen(args.path) + 1);

+	if (!ri->path) {

+		error_msg(ERROR_MSG_MEMORY, NULL);

+		exit(1);

+	}

+

+	strcpy(ri->path, args.path);

+	strcat(ri->path, args.name);

+	return 0;

+}

+

 /*

  * for a single root_info, ask the kernel to give us a path name

  * inside it's ref_root for the dir_id where it lives.

@@ -783,6 +826,11 @@ static int lookup_ino_path(int fd, struct root_info *ri)

 	ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);

 	if (ret < 0) {

+		if (errno == EPERM) {

+			/* Let's try again with the user ioctl */

+			return lookup_ino_path_user(fd, ri);

+		}

+

 		if (errno == ENOENT) {

 			ri->ref_tree = 0;

 			return -ENOENT;

-- 

2.44.0