On 2010-02-22, at 22:43, Theodore Ts'o wrote:
E2fsprogs 1.41.10 introduced a regression (in commit b71e018) where
e2fsck -fD can corrupt non-indexed directories when are exists one or
more file names which alphabetically sort before ".". This can happen
with ext2 filesystems or for small directories (take less than a
block) which contain filenames that begin with a space or some other
punctuation mark.
Fix this by making sure we never reorder the '.' or '..' entry in the
directory, since they must be first.
Ted, thanks for getting this out so fast. We were just building our
release based on 1.41.10 and are able to add this in.
Do you have a regression test for this case? e2fsck itself will
detect the corruption ("." and ".." not at the start of the directory)
after the fact, but I guess it means that there are no existing tests
where there is a directory entry that sorts before "." or it would
have been noticed earlier.
Looking at the ASCII characters before "." it seems that CVS "old
version" files with a leading ".#", "(", and "%gconf.xml" would
probably be the most likely cause of problems.
In any case, I can reproduce this easily on my filesystem with my mp3
collection (on a backup, fortunately). Unfortunately, it seems that
re-running e2fsck after such a corruption causes all (thousands) of
the entries that were sorted to the beginning of the directory to be
deleted, and moved into /lost+found.
Have you pulled this release from Sourceforge and any downstream
releases already (Debian, FC, etc)? It seems like a pretty serious
problem, even though "-fD" is likely not run very often.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
---
e2fsck/rehash.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/e2fsck/rehash.c b/e2fsck/rehash.c
index 780742e..ceb8543 100644
--- a/e2fsck/rehash.c
+++ b/e2fsck/rehash.c
@@ -763,7 +763,12 @@ retry_nohash:
/* Sort the list */
resort:
- qsort(fd.harray, fd.num_array, sizeof(struct hash_entry), hash_cmp);
+ if (fd.compress)
+ qsort(fd.harray+2, fd.num_array-2, sizeof(struct hash_entry),
+ hash_cmp);
+ else
+ qsort(fd.harray, fd.num_array, sizeof(struct hash_entry),
+ hash_cmp);
/*
* Look for duplicates
--
1.6.6.1.1.g974db.dirty
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Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
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