1 files changed, 38 insertions, 6 deletions

diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
index ab80896315be..762881b777b3 100644
--- a/fs/btrfs/reflink.c
+++ b/fs/btrfs/reflink.c
@@ -81,7 +81,10 @@ static int copy_inline_to_page(struct btrfs_inode *inode,
 		goto out_unlock;
 	}
 
-	set_page_extent_mapped(page);
+	ret = set_page_extent_mapped(page);
+	if (ret < 0)
+		goto out_unlock;
+
 	clear_extent_bit(&inode->io_tree, file_offset, range_end,
 			 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
 			 0, 0, NULL);
@@ -89,13 +92,22 @@ static int copy_inline_to_page(struct btrfs_inode *inode,
 	if (ret)
 		goto out_unlock;
 
-	if (comp_type == BTRFS_COMPRESS_NONE) {
-		char *map;
+	/*
+	 * After dirtying the page our caller will need to start a transaction,
+	 * and if we are low on metadata free space, that can cause flushing of
+	 * delalloc for all inodes in order to get metadata space released.
+	 * However we are holding the range locked for the whole duration of
+	 * the clone/dedupe operation, so we may deadlock if that happens and no
+	 * other task releases enough space. So mark this inode as not being
+	 * possible to flush to avoid such deadlock. We will clear that flag
+	 * when we finish cloning all extents, since a transaction is started
+	 * after finding each extent to clone.
+	 */
+	set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);
 
-		map = kmap(page);
-		memcpy(map, data_start, datal);
+	if (comp_type == BTRFS_COMPRESS_NONE) {
+		memcpy_to_page(page, 0, data_start, datal);
 		flush_dcache_page(page);
-		kunmap(page);
 	} else {
 		ret = btrfs_decompress(comp_type, data_start, page, 0,
 				       inline_size, datal);
@@ -537,6 +549,24 @@ process_slot:
 		 */
 		btrfs_release_path(path);
 
+		/*
+		 * When using NO_HOLES and we are cloning a range that covers
+		 * only a hole (no extents) into a range beyond the current
+		 * i_size, punching a hole in the target range will not create
+		 * an extent map defining a hole, because the range starts at or
+		 * beyond current i_size. If the file previously had an i_size
+		 * greater than the new i_size set by this clone operation, we
+		 * need to make sure the next fsync is a full fsync, so that it
+		 * detects and logs a hole covering a range from the current
+		 * i_size to the new i_size. If the clone range covers extents,
+		 * besides a hole, then we know the full sync flag was already
+		 * set by previous calls to btrfs_replace_file_extents() that
+		 * replaced file extent items.
+		 */
+		if (last_dest_end >= i_size_read(inode))
+			set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
+				&BTRFS_I(inode)->runtime_flags);
+
 		ret = btrfs_replace_file_extents(inode, path, last_dest_end,
 				destoff + len - 1, NULL, &trans);
 		if (ret)
@@ -549,6 +579,8 @@ process_slot:
 out:
 	btrfs_free_path(path);
 	kvfree(buf);
+	clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags);
+
 	return ret;
 }