btrfs-progs: minor patches to get "btrfs receive" working

pkgs/tools/filesystems/btrfsprogs/btrfs-progs-Fix-the-receive-code-pathing.patch

@@ -0,0 +1,146 @@
+diff --git a/cmds-receive.c b/cmds-receive.c
+index a8be6fa..6b7cf12 100644
+--- a/cmds-receive.c
++++ b/cmds-receive.c
+@@ -52,11 +52,13 @@ static int g_verbose = 0;
+ struct btrfs_receive
+ {
+ 	int mnt_fd;
++	int dest_dir_fd;
+
+ 	int write_fd;
+ 	char *write_path;
+
+ 	char *root_path;
++	char *dest_dir_path; /* relative to root_path */
+ 	char *full_subvol_path;
+
+ 	struct subvol_info *cur_subvol;
+@@ -150,8 +152,11 @@ static int process_subvol(const char *path, const u8 *uuid, u64 ctransid,
+ 	r->cur_subvol = calloc(1, sizeof(*r->cur_subvol));
+ 	r->parent_subvol = NULL;
+
+-	r->cur_subvol->path = strdup(path);
+-	r->full_subvol_path = path_cat(r->root_path, path);
++	if (strlen(r->dest_dir_path) == 0)
++		r->cur_subvol->path = strdup(path);
++	else
++		r->cur_subvol->path = path_cat(r->dest_dir_path, path);
++	r->full_subvol_path = path_cat3(r->root_path, r->dest_dir_path, path);
+
+ 	fprintf(stderr, "At subvol %s\n", path);
+
+@@ -167,7 +172,7 @@ static int process_subvol(const char *path, const u8 *uuid, u64 ctransid,
+
+ 	memset(&args_v1, 0, sizeof(args_v1));
+ 	strcpy(args_v1.name, path);
+-	ret = ioctl(r->mnt_fd, BTRFS_IOC_SUBVOL_CREATE, &args_v1);
++	ret = ioctl(r->dest_dir_fd, BTRFS_IOC_SUBVOL_CREATE, &args_v1);
+ 	if (ret < 0) {
+ 		ret = -errno;
+ 		fprintf(stderr, "ERROR: creating subvolume %s failed. "
+@@ -195,8 +200,11 @@ static int process_snapshot(const char *path, const u8 *uuid, u64 ctransid,
+ 	r->cur_subvol = calloc(1, sizeof(*r->cur_subvol));
+ 	r->parent_subvol = NULL;
+
+-	r->cur_subvol->path = strdup(path);
+-	r->full_subvol_path = path_cat(r->root_path, path);
++	if (strlen(r->dest_dir_path) == 0)
++		r->cur_subvol->path = strdup(path);
++	else
++		r->cur_subvol->path = path_cat(r->dest_dir_path, path);
++	r->full_subvol_path = path_cat3(r->root_path, r->dest_dir_path, path);
+
+ 	fprintf(stderr, "At snapshot %s\n", path);
+
+@@ -243,7 +251,7 @@ static int process_snapshot(const char *path, const u8 *uuid, u64 ctransid,
+ 		goto out;
+ 	}
+
+-	ret = ioctl(r->mnt_fd, BTRFS_IOC_SNAP_CREATE_V2, &args_v2);
++	ret = ioctl(r->dest_dir_fd, BTRFS_IOC_SNAP_CREATE_V2, &args_v2);
+ 	close(args_v2.fd);
+ 	if (ret < 0) {
+ 		ret = -errno;
+@@ -790,17 +798,48 @@ struct btrfs_send_ops send_ops = {
+ int do_receive(struct btrfs_receive *r, const char *tomnt, int r_fd)
+ {
+ 	int ret;
++	char *dest_dir_full_path;
+ 	int end = 0;
+
+-	r->root_path = strdup(tomnt);
+-	r->mnt_fd = open(tomnt, O_RDONLY | O_NOATIME);
++	dest_dir_full_path = realpath(tomnt, NULL);
++	if (!dest_dir_full_path) {
++		ret = -errno;
++		fprintf(stderr, "ERROR: realpath(%s) failed. %s\n", tomnt,
++				strerror(-ret));
++		goto out;
++	}
++	r->dest_dir_fd = open(dest_dir_full_path, O_RDONLY | O_NOATIME);
++	if (r->dest_dir_fd < 0) {
++		ret = -errno;
++		fprintf(stderr, "ERROR: failed to open destination directory %s. %s\n",
++			    dest_dir_full_path, strerror(-ret));
++		goto out;
++	}
++
++	ret = find_mount_root(dest_dir_full_path, &r->root_path);
++	if (ret < 0) {
++		ret = -EINVAL;
++		fprintf(stderr, "ERROR: failed to determine mount point "
++				"for %s\n", dest_dir_full_path);
++		goto out;
++	}
++	r->mnt_fd = open(r->root_path, O_RDONLY | O_NOATIME);
+ 	if (r->mnt_fd < 0) {
+ 		ret = -errno;
+-		fprintf(stderr, "ERROR: failed to open %s. %s\n", tomnt,
++		fprintf(stderr, "ERROR: failed to open %s. %s\n", r->root_path,
+ 				strerror(-ret));
+ 		goto out;
+ 	}
+
++	/*
++	 * find_mount_root returns a root_path that is a subpath of
++	 * dest_dir_full_path. Now get the other part of root_path,
++	 * which is the destination dir relative to root_path.
++	 */
++	r->dest_dir_path = dest_dir_full_path + strlen(r->root_path);
++	if (r->dest_dir_path[0] == '/')
++		r->dest_dir_path++;
++
+ 	ret = subvol_uuid_search_init(r->mnt_fd, &r->sus);
+ 	if (ret < 0)
+ 		return ret;
+diff --git a/cmds-send.c b/cmds-send.c
+index 9b47e70..c408bc7 100644
+--- a/cmds-send.c
++++ b/cmds-send.c
+@@ -81,6 +81,14 @@ int find_mount_root(const char *path, char **mount_root)
+ 		}
+ 	}
+
++	if (!longest_match) {
++		fprintf(stderr, "ERROR: Failed to find mount root for path %s.\n",
++			    path);
++		fprintf(stderr, "Please make sure that you have a valid \
++			/etc/mtab file.\n");
++		return -ENOENT;
++	}
++
+ 	*mount_root = realpath(longest_match, NULL);
+ 	free(longest_match);
+
+diff --git a/send-utils.h b/send-utils.h
+index da407eb..a3e038b 100644
+--- a/send-utils.h
++++ b/send-utils.h
+@@ -65,5 +65,6 @@ void subvol_uuid_search_add(struct subvol_uuid_search *s,
+ char *path_cat(const char *p1, const char *p2);
+ char *path_cat3(const char *p1, const char *p2, const char *p3);
+
++int find_mount_root(const char *path, char **mount_root);
+
+ #endif /* SEND_UTILS_H_ */

pkgs/tools/filesystems/btrfsprogs/btrfs-receive-help-text.patch

@@ -0,0 +1,13 @@
+diff --git a/cmds-receive.c b/cmds-receive.c
+index a8be6fa..c182175 100644
+--- a/cmds-receive.c
++++ b/cmds-receive.c
+@@ -880,7 +880,7 @@ static const char * const receive_cmd_group_usage[] = {
+ };
+
+ static const char * const cmd_receive_usage[] = {
+-	"btrfs receive [-v] [-i <infile>] <mount>",
++	"btrfs receive [-v] [-f <infile>] <mount>",
+ 	"Receive subvolumes from stdin.",
+ 	"Receives one or more subvolumes that were previously ",
+ 	"sent with btrfs send. The received subvolumes are stored",

pkgs/tools/filesystems/btrfsprogs/btrfs-receive-lchown.patch

@@ -0,0 +1,12 @@
+diff --git a/cmds-receive.c b/cmds-receive.c
+index 6b7cf12..a6a6a5b 100644
+--- a/cmds-receive.c
++++ b/cmds-receive.c
+@@ -731,7 +731,7 @@  static int process_chown(const char *path, u64 uid, u64 gid, void *user)
+ 		fprintf(stderr, "chown %s - uid=%llu, gid=%llu\n", path,
+ 				uid, gid);
+
+-	ret = chown(full_path, uid, gid);
++	ret = lchown(full_path, uid, gid);
+ 	if (ret < 0) {
+ 		ret = -errno;

pkgs/tools/filesystems/btrfsprogs/default.nix

@@ -11,7 +11,12 @@ stdenv.mkDerivation {
     sha256 = "72d4cd4fb23d876a17146d6231ad40a2151fa47c648485c54cf7478239b43764";
   };
 
-  patches = [ ./subvol-listing.patch ];
+  patches = [
+    ./subvol-listing.patch
+    ./btrfs-receive-help-text.patch
+    ./btrfs-progs-Fix-the-receive-code-pathing.patch
+    ./btrfs-receive-lchown.patch
+  ];
 
   buildInputs = [ zlib libuuid acl attr e2fsprogs ];