1 files changed, 24 insertions, 15 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index b082210df9c8..32b043ef8ac9 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -539,33 +539,23 @@ static struct btrfs_path *alloc_path_for_send(void)
 static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off)
 {
 	int ret;
-	mm_segment_t old_fs;
 	u32 pos = 0;
 
-	old_fs = get_fs();
-	set_fs(KERNEL_DS);
-
 	while (pos < len) {
-		ret = vfs_write(filp, (__force const char __user *)buf + pos,
-				len - pos, off);
+		ret = kernel_write(filp, buf + pos, len - pos, off);
 		/* TODO handle that correctly */
 		/*if (ret == -ERESTARTSYS) {
 			continue;
 		}*/
 		if (ret < 0)
-			goto out;
+			return ret;
 		if (ret == 0) {
-			ret = -EIO;
-			goto out;
+			return -EIO;
 		}
 		pos += ret;
 	}
 
-	ret = 0;
-
-out:
-	set_fs(old_fs);
-	return ret;
+	return 0;
 }
 
 static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
@@ -4733,7 +4723,7 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 	/* initial readahead */
 	memset(&sctx->ra, 0, sizeof(struct file_ra_state));
 	file_ra_state_init(&sctx->ra, inode->i_mapping);
-	btrfs_force_ra(inode->i_mapping, &sctx->ra, NULL, index,
+	page_cache_sync_readahead(inode->i_mapping, &sctx->ra, NULL, index,
 		       last_index - index + 1);
 
 	while (index <= last_index) {
@@ -4992,6 +4982,25 @@ static int clone_range(struct send_ctx *sctx,
 	struct btrfs_key key;
 	int ret;
 
+	/*
+	 * Prevent cloning from a zero offset with a length matching the sector
+	 * size because in some scenarios this will make the receiver fail.
+	 *
+	 * For example, if in the source filesystem the extent at offset 0
+	 * has a length of sectorsize and it was written using direct IO, then
+	 * it can never be an inline extent (even if compression is enabled).
+	 * Then this extent can be cloned in the original filesystem to a non
+	 * zero file offset, but it may not be possible to clone in the
+	 * destination filesystem because it can be inlined due to compression
+	 * on the destination filesystem (as the receiver's write operations are
+	 * always done using buffered IO). The same happens when the original
+	 * filesystem does not have compression enabled but the destination
+	 * filesystem has.
+	 */
+	if (clone_root->offset == 0 &&
+	    len == sctx->send_root->fs_info->sectorsize)
+		return send_extent_data(sctx, offset, len);
+
 	path = alloc_path_for_send();
 	if (!path)
 		return -ENOMEM;