Raid array setup code creates an extent buffer in an usual way. When the
PAGE_CACHE_SIZE is > super block size, the extent pages are not marked
up-to-date, which triggers a WARN_ON in the following
write_extent_buffer call. Add an explicit SetPageUptodate call to
silence the warning.
Signed-off-by: David Sterba <dste...@suse.cz>
---
fs/btrfs/volumes.c | 14 ++++++++++++++
1 files changed, 14 insertions(+), 0 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index f4b839f..732ccc6 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3699,6 +3699,20 @@ int btrfs_read_sys_array(struct btrfs_root *root)
return -ENOMEM;
btrfs_set_buffer_uptodate(sb);
btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
+ /*
+ * The sb extent buffer is artifical and just used to read the system
array.
+ * btrfs_set_buffer_uptodate() call does not properly mark all it's
+ * pages up-to-date when the page is larger: extent does not cover the
+ * whole page and consequently check_page_uptodate does not find all
+ * the page's extents up-to-date (the hole beyond sb),
+ * write_extent_buffer then triggers a WARN_ON.
+ *
+ * Regular short extents go through mark_extent_buffer_dirty/writeback
cycle,
+ * but sb spans only this function. Add an explicit SetPageUptodate call
+ * to silence the warning eg. on PowerPC 64.
+ */
+ if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
+ SetPageUptodate(extent_buffer_page(sb, 0));
write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
array_size = btrfs_super_sys_array_size(super_copy);
--
1.7.8
--
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