diff options
authorChris Mason <>2012-02-22 12:36:24 -0500
committerChris Mason <>2012-02-23 10:43:45 -0500
commit506531905296d6aee84480c879b25ea98c3f9db6 (patch)
parent16780cabb877dbd0c8c5e9ff9bdebd6c5bdd1a7b (diff)
Btrfs: clear the extent uptodate bits during parent transid failures
If btrfs reads a block and finds a parent transid mismatch, it clears the uptodate flags on the extent buffer, and the pages inside it. But we only clear the uptodate bits in the state tree if the block straddles more than one page. This is from an old optimization from to reduce contention on the extent state tree. But it is buggy because the code that retries a read from a different copy of the block is going to find the uptodate state bits set and skip the IO. The end result of the bug is that we'll never actually read the good copy (if there is one). The fix here is to always clear the uptodate state bits, which is safe because this code is only called when the parent transid fails. Signed-off-by: Chris Mason <>
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 45ca8f9b0d6..a55fbe6252d 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3871,10 +3871,9 @@ int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
num_pages = num_extent_pages(eb->start, eb->len);
clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
- if (eb_straddles_pages(eb)) {
- clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
- cached_state, GFP_NOFS);
- }
+ clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
+ cached_state, GFP_NOFS);
for (i = 0; i < num_pages; i++) {
page = extent_buffer_page(eb, i);
if (page)