Messages in this thread Patch in this message | | | From | NeilBrown <> | Date | Wed, 02 Aug 2017 13:06:18 +1000 | Subject | [PATCH 6/6] staging: lustre: llite: fix incorrect DCACHE_DISCONNECTED test |
| |
It is almost always wrong to test DCACHE_DISCONNECTED, except in "exportfs" code. The flag tells us that this dentry *might* not be connected to the root through a chain of d_parent links. Following the d_parent to an IS_ROOT() dentry *might* find one that is on the s_anon list rather than s_root.
The code here needs to know if it is safe to call __d_drop(), and the correct test is "!IS_ROOT(dentry)". If an dentry IS_ROOT(), then it might be the filesystem root, or it might be the root of a DCACHE_DISCONNECTED tree, and so be on the s_anon list. In these two cases it should not be __d_drop()ed. If !IS_ROOT(), then the dentry is attached to its parent through d_subdir, and can safely be unhashed.
Signed-off-by: NeilBrown <neilb@suse.com> --- .../staging/lustre/lustre/llite/llite_internal.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h index cd3311abf999..4854985bf4d3 100644 --- a/drivers/staging/lustre/lustre/llite/llite_internal.h +++ b/drivers/staging/lustre/lustre/llite/llite_internal.h @@ -1299,7 +1299,7 @@ static inline void d_lustre_invalidate(struct dentry *dentry, int nested) * If we unhashed such a dentry, unmount would not be able to find * it and busy inodes would be reported. */ - if (d_count(dentry) == 0 && !(dentry->d_flags & DCACHE_DISCONNECTED)) + if (d_count(dentry) == 0 && !IS_ROOT(dentry)) __d_drop(dentry); spin_unlock(&dentry->d_lock); }
| |