On 9/8/14 9:25 AM, Brian Foster wrote:
On Mon, Sep 08, 2014 at 09:45:25AM -0400, Brian Foster wrote:
On Sun, Sep 07, 2014 at 11:41:03AM -0500, Eric Sandeen wrote:
In phase 6's longform_dir2_entry_check, if we never
find a '.' entry we never add a reference to that entry;
if we subsequently rebuild it, '.' gets added, but
no ref to it is ever made. This leads to Phase 7 doing
i.e.:
Phase 7 - verify and correct link counts...
resetting inode 5184 nlinks from 2 to 1
and the next run will do:
Phase 7 - verify and correct link counts...
resetting inode 5184 nlinks from 1 to 2
So if '.' was never found, but the directory got
rebuilt, manually add the ref for it.
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
repair/phase6.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/repair/phase6.c b/repair/phase6.c
index f13069f..cc36a9c 100644
--- a/repair/phase6.c
+++ b/repair/phase6.c
@@ -2288,6 +2288,12 @@ out_fix:
if (bplist[i])
libxfs_putbuf(bplist[i]);
longform_dir2_rebuild(mp, ino, ip, irec, ino_offset, hashtab);
+ /*
+ * If we didn't find a dot, we never added a ref for it;
+ * it's there now after the rebuild, so mark it as reached.
+ */
+ if (*need_dot)
+ add_inode_ref(irec, ino_offset);
So if I follow this correctly, we iterate through the dir, add each name
to the hashtable and handle the inode reference count in the first
longform_dir2_entry_check() loop. If something is wrong, we call
longform_dir2_rebuild() to rebuild the dir from the hashtable of
names/inodes. We may or may not have added a reference for dot at that
point, and need_dot is set appropriately.
This seems Ok, but where is the dot entry actually added? Hmm, I see
that we handle dot in the longform_dir2_rebuild() loop by just skipping
over it...
It looks like this happens in process_dir_inode() after this whole
check/rebuild sequence, directory format permitting. There's also an
add_inode_ref() there. Perhaps the bug here is that we clear need_dot
when we shouldn't..?
If we do that, the first run says:
bad hash table for directory inode 5184 (no data entry): rebuilding
rebuilding directory inode 5184
creating missing "." entry in dir ino 5184
and then the 2nd run says:
multiple . entries in directory inode 5184: clearing entry
so, no. ;)
The issue is that add_inode_ref() is keeping track (in repair)
of reached paths to the inode, in counted_nlinks.
If we didn't find '.' originally, we didn't add that ref.
When we do:
longform_dir2_rebuild
xfs_dir_init() // creates shortform
<loop over names>
xfs_dir_createname
xfs_dir2_sf_to_block when it's big enough
add '.' entry
and then we've added the '.' but haven't added the reference repair needs
internally.
-Eric
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