Hi Tao,
Thanks for reporting the problem and submitting a test case. I've
kept the regression test case (although I ended up renaming it).
However, I think a better fix is to change e2fsck, since it wasn't
making a check that it shouldn't have been making in the first place.
The commit description describes the fix which I think is better....
- Ted
commit 9c40d14841f04811097a123d6e8555e78ce56811
Author: Theodore Ts'o <tytso@xxxxxxx>
Date: Mon Jun 11 00:25:45 2012 -0400
e2fsck: only check for zero-length leaf extents
The on-disk format for interior nodes in the extent tree does not
encode the length of each entry in the interior node; instead, it is
synthesized/simulated by the extent library code in libext2fs.
Unfortunately, this simulation is not perfect; in particular it does
not work for the last extent in the extent tree if there are
uninitialized blocks allocated using fallocate with
FALLOC_FL_KEEP_SIZE, and it leads to e2fsck incorrectly complaining
about an invalid zero-length extent.
We only need to worry about the extent length for the leaves of the
tree, since it is there were we are checking an on-disk value, as
opposed to a software-generated simulation. So restrict the check of
extent length to leaf nodes in the extent tree.
Reported-by: Tao Ma <tm@xxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index c6aae6e..72dcd97 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -1779,7 +1779,7 @@ static void scan_extent_node(e2fsck_t ctx, struct problem_context *pctx,
problem = PR_1_EXTENT_BAD_START_BLK;
else if (extent.e_lblk < start_block)
problem = PR_1_OUT_OF_ORDER_EXTENTS;
- else if (extent.e_len == 0)
+ else if (is_leaf && extent.e_len == 0)
problem = PR_1_EXTENT_LENGTH_ZERO;
else if (is_leaf &&
(extent.e_pblk + extent.e_len) >
--
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