[PATCH 3.12 012/142] Btrfs: fix compressed write corruption on enospc

[Jiri Slaby]

From: Liu Bo <bo.li.liu@xxxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit ce62003f690dff38d3164a632ec69efa15c32cbf upstream.

When failing to allocate space for the whole compressed extent, we'll
fallback to uncompressed IO, but we've forgotten to redirty the pages
which belong to this compressed extent, and these 'clean' pages will
simply skip 'submit' part and go to endio directly, at last we got data
corruption as we write nothing.

Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
Tested-By: Martin Steigerwald <martin@xxxxxxxxxxxx>
Signed-off-by: Chris Mason <clm@xxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 fs/btrfs/inode.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index fa8010c1b628..7e6758d075ad 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -683,6 +683,18 @@ retry:
 				unlock_extent(io_tree, async_extent->start,
 					      async_extent->start +
 					      async_extent->ram_size - 1);
+
+				/*
+				 * we need to redirty the pages if we decide to
+				 * fallback to uncompressed IO, otherwise we
+				 * will not submit these pages down to lower
+				 * layers.
+				 */
+				extent_range_redirty_for_io(inode,
+						async_extent->start,
+						async_extent->start +
+						async_extent->ram_size - 1);
+
 				goto retry;
 			}
 			goto out_free;
-- 
2.1.0

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