From cb44921a09221f0a90217b44044448f63190f3e5 Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Sun, 24 Oct 2010 11:01:27 -0400
Subject: [PATCH] Btrfs: don't loop forever on bad btree blocks
When btrfs discovers the generation number in a btree block is
incorrect, it can loop forever without forcing the RAID
code to try a valid mirror, and without returning EIO.
This changes things to properly kick out the EIO.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
fs/btrfs/ctree.c | 37 ++++++++++++++++++++++++++++---------
1 file changed, 28 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index c3df14ce2cc2..6921231e0efb 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1577,13 +1577,33 @@ read_block_for_search(struct btrfs_trans_handle *trans,
blocksize = btrfs_level_size(root, level - 1);
tmp = btrfs_find_tree_block(root, blocknr, blocksize);
- if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
- /*
- * we found an up to date block without sleeping, return
- * right away
- */
- *eb_ret = tmp;
- return 0;
+ if (tmp) {
+ if (btrfs_buffer_uptodate(tmp, 0)) {
+ if (btrfs_buffer_uptodate(tmp, gen)) {
+ /*
+ * we found an up to date block without
+ * sleeping, return
+ * right away
+ */
+ *eb_ret = tmp;
+ return 0;
+ }
+ /* the pages were up to date, but we failed
+ * the generation number check. Do a full
+ * read for the generation number that is correct.
+ * We must do this without dropping locks so
+ * we can trust our generation number
+ */
+ free_extent_buffer(tmp);
+ tmp = read_tree_block(root, blocknr, blocksize, gen);
+ if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
+ *eb_ret = tmp;
+ return 0;
+ }
+ free_extent_buffer(tmp);
+ btrfs_release_path(NULL, p);
+ return -EIO;
+ }
}
/*
@@ -1596,8 +1616,7 @@ read_block_for_search(struct btrfs_trans_handle *trans,
btrfs_unlock_up_safe(p, level + 1);
btrfs_set_path_blocking(p);
- if (tmp)
- free_extent_buffer(tmp);
+ free_extent_buffer(tmp);
if (p->reada)
reada_for_search(root, p, level, slot, key->objectid);
--
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