When a directory hierarchy is corrupted (e. g. due to a bit flip on the media),
it can happen that it contains loops of directories. That creates possibilities
for deadlock when locking directories.
Fix the problem by checking in d_splice_alias() that when we splice a
directory, it does not have any other connected alias.
Reported-by: Sami Liedes <sami.liedes@xxxxxx>
CC: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/dcache.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
Sorry guys, I'm resending this again because I messed up list address
previously.
diff --git a/fs/dcache.c b/fs/dcache.c
index 4046904..afe81fe 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1658,6 +1658,11 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
d_move(new, dentry);
iput(inode);
} else {
+ if (unlikely(!list_empty(&inode->i_dentry))) {
+ spin_unlock(&inode->i_lock);
+ iput(inode);
+ return ERR_PTR(-EIO);
+ }
/* already taking inode->i_lock, so d_add() by hand */
__d_instantiate(dentry, inode);
spin_unlock(&inode->i_lock);
--
1.7.1
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