1 files changed, 42 insertions, 75 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 9b6da9d55f9a..1ac3ca98c429 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -493,6 +493,7 @@ static struct btrfs_path *alloc_path_for_send(void)
 		return NULL;
 	path->search_commit_root = 1;
 	path->skip_locking = 1;
+	path->need_commit_sem = 1;
 	return path;
 }
 
@@ -771,29 +772,22 @@ out:
 /*
  * Helper function to retrieve some fields from an inode item.
  */
-static int get_inode_info(struct btrfs_root *root,
-			  u64 ino, u64 *size, u64 *gen,
-			  u64 *mode, u64 *uid, u64 *gid,
-			  u64 *rdev)
+static int __get_inode_info(struct btrfs_root *root, struct btrfs_path *path,
+			  u64 ino, u64 *size, u64 *gen, u64 *mode, u64 *uid,
+			  u64 *gid, u64 *rdev)
 {
 	int ret;
 	struct btrfs_inode_item *ii;
 	struct btrfs_key key;
-	struct btrfs_path *path;
-
-	path = alloc_path_for_send();
-	if (!path)
-		return -ENOMEM;
 
 	key.objectid = ino;
 	key.type = BTRFS_INODE_ITEM_KEY;
 	key.offset = 0;
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-	if (ret < 0)
-		goto out;
 	if (ret) {
-		ret = -ENOENT;
-		goto out;
+		if (ret > 0)
+			ret = -ENOENT;
+		return ret;
 	}
 
 	ii = btrfs_item_ptr(path->nodes[0], path->slots[0],
@@ -811,7 +805,22 @@ static int get_inode_info(struct btrfs_root *root,
 	if (rdev)
 		*rdev = btrfs_inode_rdev(path->nodes[0], ii);
 
-out:
+	return ret;
+}
+
+static int get_inode_info(struct btrfs_root *root,
+			  u64 ino, u64 *size, u64 *gen,
+			  u64 *mode, u64 *uid, u64 *gid,
+			  u64 *rdev)
+{
+	struct btrfs_path *path;
+	int ret;
+
+	path = alloc_path_for_send();
+	if (!path)
+		return -ENOMEM;
+	ret = __get_inode_info(root, path, ino, size, gen, mode, uid, gid,
+			       rdev);
 	btrfs_free_path(path);
 	return ret;
 }
@@ -1085,6 +1094,7 @@ out:
 struct backref_ctx {
 	struct send_ctx *sctx;
 
+	struct btrfs_path *path;
 	/* number of total found references */
 	u64 found;
 
@@ -1155,8 +1165,9 @@ static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_)
 	 * There are inodes that have extents that lie behind its i_size. Don't
 	 * accept clones from these extents.
 	 */
-	ret = get_inode_info(found->root, ino, &i_size, NULL, NULL, NULL, NULL,
-			NULL);
+	ret = __get_inode_info(found->root, bctx->path, ino, &i_size, NULL, NULL,
+			       NULL, NULL, NULL);
+	btrfs_release_path(bctx->path);
 	if (ret < 0)
 		return ret;
 
@@ -1235,12 +1246,17 @@ static int find_extent_clone(struct send_ctx *sctx,
 	if (!tmp_path)
 		return -ENOMEM;
 
+	/* We only use this path under the commit sem */
+	tmp_path->need_commit_sem = 0;
+
 	backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_NOFS);
 	if (!backref_ctx) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
+	backref_ctx->path = tmp_path;
+
 	if (data_offset >= ino_size) {
 		/*
 		 * There may be extents that lie behind the file's size.
@@ -1268,8 +1284,10 @@ static int find_extent_clone(struct send_ctx *sctx,
 	}
 	logical = disk_byte + btrfs_file_extent_offset(eb, fi);
 
+	down_read(&sctx->send_root->fs_info->commit_root_sem);
 	ret = extent_from_logical(sctx->send_root->fs_info, disk_byte, tmp_path,
 				  &found_key, &flags);
+	up_read(&sctx->send_root->fs_info->commit_root_sem);
 	btrfs_release_path(tmp_path);
 
 	if (ret < 0)
@@ -4418,6 +4436,9 @@ static int send_hole(struct send_ctx *sctx, u64 end)
 	p = fs_path_alloc();
 	if (!p)
 		return -ENOMEM;
+	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+	if (ret < 0)
+		goto tlv_put_failure;
 	memset(sctx->read_buf, 0, BTRFS_SEND_READ_SIZE);
 	while (offset < end) {
 		len = min_t(u64, end - offset, BTRFS_SEND_READ_SIZE);
@@ -4425,9 +4446,6 @@ static int send_hole(struct send_ctx *sctx, u64 end)
 		ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
 		if (ret < 0)
 			break;
-		ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
-		if (ret < 0)
-			break;
 		TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
 		TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
 		TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len);
@@ -4968,7 +4986,9 @@ static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
 
 	if (S_ISREG(sctx->cur_inode_mode)) {
 		if (need_send_hole(sctx)) {
-			if (sctx->cur_inode_last_extent == (u64)-1) {
+			if (sctx->cur_inode_last_extent == (u64)-1 ||
+			    sctx->cur_inode_last_extent <
+			    sctx->cur_inode_size) {
 				ret = get_last_extent(sctx, (u64)-1);
 				if (ret)
 					goto out;
@@ -5367,57 +5387,21 @@ out:
 static int full_send_tree(struct send_ctx *sctx)
 {
 	int ret;
-	struct btrfs_trans_handle *trans = NULL;
 	struct btrfs_root *send_root = sctx->send_root;
 	struct btrfs_key key;
 	struct btrfs_key found_key;
 	struct btrfs_path *path;
 	struct extent_buffer *eb;
 	int slot;
-	u64 start_ctransid;
-	u64 ctransid;
 
 	path = alloc_path_for_send();
 	if (!path)
 		return -ENOMEM;
 
-	spin_lock(&send_root->root_item_lock);
-	start_ctransid = btrfs_root_ctransid(&send_root->root_item);
-	spin_unlock(&send_root->root_item_lock);
-
 	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 	key.type = BTRFS_INODE_ITEM_KEY;
 	key.offset = 0;
 
-join_trans:
-	/*
-	 * We need to make sure the transaction does not get committed
-	 * while we do anything on commit roots. Join a transaction to prevent
-	 * this.
-	 */
-	trans = btrfs_join_transaction(send_root);
-	if (IS_ERR(trans)) {
-		ret = PTR_ERR(trans);
-		trans = NULL;
-		goto out;
-	}
-
-	/*
-	 * Make sure the tree has not changed after re-joining. We detect this
-	 * by comparing start_ctransid and ctransid. They should always match.
-	 */
-	spin_lock(&send_root->root_item_lock);
-	ctransid = btrfs_root_ctransid(&send_root->root_item);
-	spin_unlock(&send_root->root_item_lock);
-
-	if (ctransid != start_ctransid) {
-		WARN(1, KERN_WARNING "BTRFS: the root that you're trying to "
-				     "send was modified in between. This is "
-				     "probably a bug.\n");
-		ret = -EIO;
-		goto out;
-	}
-
 	ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
 	if (ret < 0)
 		goto out;
@@ -5425,19 +5409,6 @@ join_trans:
 		goto out_finish;
 
 	while (1) {
-		/*
-		 * When someone want to commit while we iterate, end the
-		 * joined transaction and rejoin.
-		 */
-		if (btrfs_should_end_transaction(trans, send_root)) {
-			ret = btrfs_end_transaction(trans, send_root);
-			trans = NULL;
-			if (ret < 0)
-				goto out;
-			btrfs_release_path(path);
-			goto join_trans;
-		}
-
 		eb = path->nodes[0];
 		slot = path->slots[0];
 		btrfs_item_key_to_cpu(eb, &found_key, slot);
@@ -5465,12 +5436,6 @@ out_finish:
 
 out:
 	btrfs_free_path(path);
-	if (trans) {
-		if (!ret)
-			ret = btrfs_end_transaction(trans, send_root);
-		else
-			btrfs_end_transaction(trans, send_root);
-	}
 	return ret;
 }
 
@@ -5718,7 +5683,9 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
 			NULL);
 	sort_clone_roots = 1;
 
+	current->journal_info = (void *)BTRFS_SEND_TRANS_STUB;
 	ret = send_subvol(sctx);
+	current->journal_info = NULL;
 	if (ret < 0)
 		goto out;