| From b18dafc86bb879d2f38a1743985d7ceb283c2f4d Mon Sep 17 00:00:00 2001 |
| From: Michel Lespinasse <walken@google.com> |
| Date: Mon, 26 Mar 2012 17:32:44 -0700 |
| Subject: vfs: fix d_ancestor() case in d_materialize_unique |
| |
| From: Michel Lespinasse <walken@google.com> |
| |
| commit b18dafc86bb879d2f38a1743985d7ceb283c2f4d upstream. |
| |
| In d_materialise_unique() there are 3 subcases to the 'aliased dentry' |
| case; in two subcases the inode i_lock is properly released but this |
| does not occur in the -ELOOP subcase. |
| |
| This seems to have been introduced by commit 1836750115f2 ("fix loop |
| checks in d_materialise_unique()"). |
| |
| Signed-off-by: Michel Lespinasse <walken@google.com> |
| [ Added a comment, and moved the unlock to where we generate the -ELOOP, |
| which seems to be more natural. |
| |
| You probably can't actually trigger this without a buggy network file |
| server - d_materialize_unique() is for finding aliases on non-local |
| filesystems, and the d_ancestor() case is for a hardlinked directory |
| loop. |
| |
| But we should be robust in the case of such buggy servers anyway. ] |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/dcache.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/fs/dcache.c |
| +++ b/fs/dcache.c |
| @@ -2357,6 +2357,7 @@ struct dentry *d_materialise_unique(stru |
| if (d_ancestor(alias, dentry)) { |
| /* Check for loops */ |
| actual = ERR_PTR(-ELOOP); |
| + spin_unlock(&inode->i_lock); |
| } else if (IS_ROOT(alias)) { |
| /* Is this an anonymous mountpoint that we |
| * could splice into our tree? */ |
| @@ -2366,7 +2367,7 @@ struct dentry *d_materialise_unique(stru |
| goto found; |
| } else { |
| /* Nope, but we must(!) avoid directory |
| - * aliasing */ |
| + * aliasing. This drops inode->i_lock */ |
| actual = __d_unalias(inode, dentry, alias); |
| } |
| write_sequnlock(&rename_lock); |
