1 files changed, 160 insertions, 95 deletions

diff --git a/cmds-send.c b/cmds-send.c
index 74d01287..cec11e6b 100644
--- a/cmds-send.c
+++ b/cmds-send.c
@@ -44,6 +44,8 @@
 #include "send.h"
 #include "send-utils.h"
 
+#define SEND_BUFFER_SIZE	(64 * 1024)
+
 /*
  * Default is 1 for historical reasons, changing may break scripts that expect
  * the 'At subvol' message.
@@ -62,64 +64,72 @@ struct btrfs_send {
 	struct subvol_uuid_search sus;
 };
 
-static int get_root_id(struct btrfs_send *s, const char *path, u64 *root_id)
+static int get_root_id(struct btrfs_send *sctx, const char *path, u64 *root_id)
 {
 	struct subvol_info *si;
 
-	si = subvol_uuid_search(&s->sus, 0, NULL, 0, path,
+	si = subvol_uuid_search(&sctx->sus, 0, NULL, 0, path,
 			subvol_search_by_path);
-	if (!si)
-		return -ENOENT;
+	if (IS_ERR_OR_NULL(si)) {
+		if (!si)
+			return -ENOENT;
+		else
+			return PTR_ERR(si);
+	}
 	*root_id = si->root_id;
 	free(si->path);
 	free(si);
 	return 0;
 }
 
-static struct subvol_info *get_parent(struct btrfs_send *s, u64 root_id)
+static struct subvol_info *get_parent(struct btrfs_send *sctx, u64 root_id)
 {
 	struct subvol_info *si_tmp;
 	struct subvol_info *si;
 
-	si_tmp = subvol_uuid_search(&s->sus, root_id, NULL, 0, NULL,
+	si_tmp = subvol_uuid_search(&sctx->sus, root_id, NULL, 0, NULL,
 			subvol_search_by_root_id);
-	if (!si_tmp)
-		return NULL;
+	if (IS_ERR_OR_NULL(si_tmp))
+		return si_tmp;
 
-	si = subvol_uuid_search(&s->sus, 0, si_tmp->parent_uuid, 0, NULL,
+	si = subvol_uuid_search(&sctx->sus, 0, si_tmp->parent_uuid, 0, NULL,
 			subvol_search_by_uuid);
 	free(si_tmp->path);
 	free(si_tmp);
 	return si;
 }
 
-static int find_good_parent(struct btrfs_send *s, u64 root_id, u64 *found)
+static int find_good_parent(struct btrfs_send *sctx, u64 root_id, u64 *found)
 {
 	int ret;
 	struct subvol_info *parent = NULL;
 	struct subvol_info *parent2 = NULL;
 	struct subvol_info *best_parent = NULL;
-	__s64 tmp;
 	u64 best_diff = (u64)-1;
 	int i;
 
-	parent = get_parent(s, root_id);
-	if (!parent) {
-		ret = -ENOENT;
+	parent = get_parent(sctx, root_id);
+	if (IS_ERR_OR_NULL(parent)) {
+		if (!parent)
+			ret = -ENOENT;
+		else
+			ret = PTR_ERR(parent);
 		goto out;
 	}
 
-	for (i = 0; i < s->clone_sources_count; i++) {
-		if (s->clone_sources[i] == parent->root_id) {
+	for (i = 0; i < sctx->clone_sources_count; i++) {
+		if (sctx->clone_sources[i] == parent->root_id) {
 			best_parent = parent;
 			parent = NULL;
 			goto out_found;
 		}
 	}
 
-	for (i = 0; i < s->clone_sources_count; i++) {
-		parent2 = get_parent(s, s->clone_sources[i]);
-		if (!parent2)
+	for (i = 0; i < sctx->clone_sources_count; i++) {
+		s64 tmp;
+
+		parent2 = get_parent(sctx, sctx->clone_sources[i]);
+		if (IS_ERR_OR_NULL(parent2))
 			continue;
 		if (parent2->root_id != parent->root_id) {
 			free(parent2->path);
@@ -130,16 +140,19 @@ static int find_good_parent(struct btrfs_send *s, u64 root_id, u64 *found)
 
 		free(parent2->path);
 		free(parent2);
-		parent2 = subvol_uuid_search(&s->sus, s->clone_sources[i], NULL,
-				0, NULL, subvol_search_by_root_id);
-
-		if (!parent2) {
-			ret = -ENOENT;
+		parent2 = subvol_uuid_search(&sctx->sus,
+				sctx->clone_sources[i], NULL, 0, NULL,
+				subvol_search_by_root_id);
+		if (IS_ERR_OR_NULL(parent2)) {
+			if (!parent2)
+				ret = -ENOENT;
+			else
+				ret = PTR_ERR(parent2);
 			goto out;
 		}
 		tmp = parent2->ctransid - parent->ctransid;
 		if (tmp < 0)
-			tmp *= -1;
+			tmp = -tmp;
 		if (tmp < best_diff) {
 			if (best_parent) {
 				free(best_parent->path);
@@ -176,41 +189,44 @@ out:
 	return ret;
 }
 
-static int add_clone_source(struct btrfs_send *s, u64 root_id)
+static int add_clone_source(struct btrfs_send *sctx, u64 root_id)
 {
 	void *tmp;
 
-	tmp = s->clone_sources;
-	s->clone_sources = realloc(s->clone_sources,
-		sizeof(*s->clone_sources) * (s->clone_sources_count + 1));
+	tmp = sctx->clone_sources;
+	sctx->clone_sources = realloc(sctx->clone_sources,
+		sizeof(*sctx->clone_sources) * (sctx->clone_sources_count + 1));
 
-	if (!s->clone_sources) {
+	if (!sctx->clone_sources) {
 		free(tmp);
 		return -ENOMEM;
 	}
-	s->clone_sources[s->clone_sources_count++] = root_id;
+	sctx->clone_sources[sctx->clone_sources_count++] = root_id;
 
 	return 0;
 }
 
-static int write_buf(int fd, const void *buf, int size)
+#if 0
+static int write_buf(int fd, const char *buf, size_t size)
 {
 	int ret;
-	int pos = 0;
+	size_t pos = 0;
 
 	while (pos < size) {
-		ret = write(fd, (char*)buf + pos, size - pos);
-		if (ret < 0) {
+		ssize_t wbytes;
+
+		wbytes = write(fd, buf + pos, size - pos);
+		if (wbytes < 0) {
 			ret = -errno;
 			error("failed to dump stream: %s", strerror(-ret));
 			goto out;
 		}
-		if (!ret) {
+		if (!wbytes) {
 			ret = -EIO;
 			error("failed to dump stream: %s", strerror(-ret));
 			goto out;
 		}
-		pos += ret;
+		pos += wbytes;
 	}
 	ret = 0;
 
@@ -218,40 +234,71 @@ out:
 	return ret;
 }
 
-static void *dump_thread(void *arg_)
+static void* read_sent_data_copy(void *arg)
 {
 	int ret;
-	struct btrfs_send *s = (struct btrfs_send*)arg_;
-	char buf[4096];
-	int readed;
+	struct btrfs_send *sctx = (struct btrfs_send*)arg;
+	char buf[SEND_BUFFER_SIZE];
 
 	while (1) {
-		readed = read(s->send_fd, buf, sizeof(buf));
-		if (readed < 0) {
+		ssize_t rbytes;
+
+		rbytes = read(sctx->send_fd, buf, sizeof(buf));
+		if (rbytes < 0) {
 			ret = -errno;
-			error("failed to read stream from kernel: %s\n",
+			error("failed to read stream from kernel: %s",
 				strerror(-ret));
 			goto out;
 		}
-		if (!readed) {
+		if (!rbytes) {
 			ret = 0;
 			goto out;
 		}
-		ret = write_buf(s->dump_fd, buf, readed);
+		ret = write_buf(sctx->dump_fd, buf, rbytes);
 		if (ret < 0)
 			goto out;
 	}
 
 out:
-	if (ret < 0) {
+	if (ret < 0)
 		exit(-ret);
+
+	return ERR_PTR(ret);
+}
+#endif
+
+static void *read_sent_data(void *arg)
+{
+	int ret;
+	struct btrfs_send *sctx = (struct btrfs_send*)arg;
+
+	while (1) {
+		ssize_t sbytes;
+
+		/* Source is a pipe, output is either file or stdout */
+		sbytes = splice(sctx->send_fd, NULL, sctx->dump_fd,
+				NULL, SEND_BUFFER_SIZE, SPLICE_F_MORE);
+		if (sbytes < 0) {
+			ret = -errno;
+			error("failed to read stream from kernel: %s",
+				strerror(-ret));
+			goto out;
+		}
+		if (!sbytes) {
+			ret = 0;
+			goto out;
+		}
 	}
 
+out:
+	if (ret < 0)
+		exit(-ret);
+
 	return ERR_PTR(ret);
 }
 
 static int do_send(struct btrfs_send *send, u64 parent_root_id,
-		   int is_first_subvol, int is_last_subvol, char *subvol,
+		   int is_first_subvol, int is_last_subvol, const char *subvol,
 		   u64 flags)
 {
 	int ret;
@@ -280,8 +327,7 @@ static int do_send(struct btrfs_send *send, u64 parent_root_id,
 	send->send_fd = pipefd[0];
 
 	if (!ret)
-		ret = pthread_create(&t_read, NULL, dump_thread,
-					send);
+		ret = pthread_create(&t_read, NULL, read_sent_data, send);
 	if (ret) {
 		ret = -ret;
 		error("thread setup failed: %s", strerror(-ret));
@@ -339,14 +385,14 @@ out:
 	return ret;
 }
 
-static int init_root_path(struct btrfs_send *s, const char *subvol)
+static int init_root_path(struct btrfs_send *sctx, const char *subvol)
 {
 	int ret = 0;
 
-	if (s->root_path)
+	if (sctx->root_path)
 		goto out;
 
-	ret = find_mount_root(subvol, &s->root_path);
+	ret = find_mount_root(subvol, &sctx->root_path);
 	if (ret < 0) {
 		error("failed to determine mount point for %s: %s",
 			subvol, strerror(-ret));
@@ -359,14 +405,14 @@ static int init_root_path(struct btrfs_send *s, const char *subvol)
 		goto out;
 	}
 
-	s->mnt_fd = open(s->root_path, O_RDONLY | O_NOATIME);
-	if (s->mnt_fd < 0) {
+	sctx->mnt_fd = open(sctx->root_path, O_RDONLY | O_NOATIME);
+	if (sctx->mnt_fd < 0) {
 		ret = -errno;
-		error("cannot open '%s': %s", s->root_path, strerror(-ret));
+		error("cannot open '%s': %s", sctx->root_path, strerror(-ret));
 		goto out;
 	}
 
-	ret = subvol_uuid_search_init(s->mnt_fd, &s->sus);
+	ret = subvol_uuid_search_init(sctx->mnt_fd, &sctx->sus);
 	if (ret < 0) {
 		error("failed to initialize subvol search: %s",
 			strerror(-ret));
@@ -378,13 +424,13 @@ out:
 
 }
 
-static int is_subvol_ro(struct btrfs_send *s, char *subvol)
+static int is_subvol_ro(struct btrfs_send *sctx, const char *subvol)
 {
 	int ret;
 	u64 flags;
 	int fd = -1;
 
-	fd = openat(s->mnt_fd, subvol, O_RDONLY | O_NOATIME);
+	fd = openat(sctx->mnt_fd, subvol, O_RDONLY | O_NOATIME);
 	if (fd < 0) {
 		ret = -errno;
 		error("cannot open %s: %s", subvol, strerror(-ret));
@@ -411,6 +457,37 @@ out:
 	return ret;
 }
 
+static int set_root_info(struct btrfs_send *sctx, const char *subvol,
+		u64 *root_id)
+{
+	int ret;
+
+	ret = init_root_path(sctx, subvol);
+	if (ret < 0)
+		goto out;
+
+	ret = get_root_id(sctx, subvol_strip_mountpoint(sctx->root_path, subvol),
+		root_id);
+	if (ret < 0) {
+		error("cannot resolve rootid for %s", subvol);
+		goto out;
+	}
+
+out:
+	return ret;
+}
+
+static void free_send_info(struct btrfs_send *sctx)
+{
+	if (sctx->mnt_fd >= 0) {
+		close(sctx->mnt_fd);
+		sctx->mnt_fd = -1;
+	}
+	free(sctx->root_path);
+	sctx->root_path = NULL;
+	subvol_uuid_search_finit(&sctx->sus);
+}
+
 int cmd_send(int argc, char **argv)
 {
 	char *subvol = NULL;
@@ -460,18 +537,10 @@ int cmd_send(int argc, char **argv)
 				goto out;
 			}
 
-			ret = init_root_path(&send, subvol);
+			ret = set_root_info(&send, subvol, &root_id);
 			if (ret < 0)
 				goto out;
 
-			ret = get_root_id(&send,
-				subvol_strip_mountpoint(send.root_path, subvol),
-				&root_id);
-			if (ret < 0) {
-				error("cannot resolve rootid for %s", subvol);
-				goto out;
-			}
-
 			ret = is_subvol_ro(&send, subvol);
 			if (ret < 0)
 				goto out;
@@ -486,15 +555,9 @@ int cmd_send(int argc, char **argv)
 				error("cannot add clone source: %s", strerror(-ret));
 				goto out;
 			}
-			subvol_uuid_search_finit(&send.sus);
 			free(subvol);
 			subvol = NULL;
-			if (send.mnt_fd >= 0) {
-				close(send.mnt_fd);
-				send.mnt_fd = -1;
-			}
-			free(send.root_path);
-			send.root_path = NULL;
+			free_send_info(&send);
 			full_send = 0;
 			break;
 		case 'f':
@@ -548,7 +611,20 @@ int cmd_send(int argc, char **argv)
 		usage(cmd_send_usage);
 
 	if (outname[0]) {
-		send.dump_fd = creat(outname, 0600);
+		int tmpfd;
+
+		/*
+		 * Try to use an existing file first. Even if send runs as
+		 * root, it might not have permissions to create file (eg. on a
+		 * NFS) but it should still be able to use a pre-created file.
+		 */
+		tmpfd = open(outname, O_WRONLY | O_TRUNC);
+		if (tmpfd < 0) {
+			if (errno == ENOENT)
+				tmpfd = open(outname,
+					O_CREAT | O_WRONLY | O_TRUNC, 0600);
+		}
+		send.dump_fd = tmpfd;
 		if (send.dump_fd == -1) {
 			ret = -errno;
 			error("cannot create '%s': %s", outname, strerror(-ret));
@@ -564,8 +640,6 @@ int cmd_send(int argc, char **argv)
 	}
 
 	/* use first send subvol to determine mount_root */
-	subvol = argv[optind];
-
 	subvol = realpath(argv[optind], NULL);
 	if (!subvol) {
 		ret = -errno;
@@ -652,7 +726,11 @@ int cmd_send(int argc, char **argv)
 			goto out;
 		}
 
-		if (!full_send && !parent_root_id) {
+		if (!full_send && !snapshot_parent) {
+			ret = set_root_info(&send, subvol, &root_id);
+			if (ret < 0)
+				goto out;
+
 			ret = find_good_parent(&send, root_id, &parent_root_id);
 			if (ret < 0) {
 				error("parent determination failed for %lld",
@@ -661,15 +739,6 @@ int cmd_send(int argc, char **argv)
 			}
 		}
 
-		ret = is_subvol_ro(&send, subvol);
-		if (ret < 0)
-			goto out;
-		if (!ret) {
-			ret = -EINVAL;
-			error("subvolume %s is not read-only", subvol);
-			goto out;
-		}
-
 		if (new_end_cmd_semantic) {
 			/* require new kernel */
 			is_first_subvol = (i == optind);
@@ -684,16 +753,15 @@ int cmd_send(int argc, char **argv)
 		if (ret < 0)
 			goto out;
 
-		if (!full_send) {
+		if (!full_send && !snapshot_parent) {
 			/* done with this subvol, so add it to the clone sources */
 			ret = add_clone_source(&send, root_id);
 			if (ret < 0) {
 				error("cannot add clone source: %s", strerror(-ret));
 				goto out;
 			}
+			free_send_info(&send);
 		}
-
-		parent_root_id = 0;
 	}
 
 	ret = 0;
@@ -702,10 +770,7 @@ out:
 	free(subvol);
 	free(snapshot_parent);
 	free(send.clone_sources);
-	if (send.mnt_fd >= 0)
-		close(send.mnt_fd);
-	free(send.root_path);
-	subvol_uuid_search_finit(&send.sus);
+	free_send_info(&send);
 	return !!ret;
 }