From: J. Bruce Fields Date: Tue, 15 Oct 2013 21:03:16 +0000 (-0400) Subject: nfs: use IS_ROOT not DCACHE_DISCONNECTED X-Git-Tag: v5.15~18830^2~26 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a3f432bfd06a4ec3b812e32d3266e0d1ad75d008;p=platform%2Fkernel%2Flinux-starfive.git nfs: use IS_ROOT not DCACHE_DISCONNECTED This check was added by Al Viro with d9e80b7de91db05c1c4d2e5ebbfd70b3b3ba0e0f "nfs d_revalidate() is too trigger-happy with d_drop()", with the explanation that we don't want to remove the root of a disconnected tree, which will still be included on the s_anon list. But DCACHE_DISCONNECTED does *not* actually identify dentries that are disconnected from the dentry tree or hashed on s_anon. IS_ROOT() is the way to do that. Also add a comment from Al's commit to remind us why this check is there. Signed-off-by: J. Bruce Fields Reviewed-by: Christoph Hellwig Signed-off-by: Trond Myklebust --- diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 02b0df7..6cc51ae 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1139,7 +1139,13 @@ out_zap_parent: if (inode && S_ISDIR(inode->i_mode)) { /* Purge readdir caches. */ nfs_zap_caches(inode); - if (dentry->d_flags & DCACHE_DISCONNECTED) + /* + * We can't d_drop the root of a disconnected tree: + * its d_hash is on the s_anon list and d_drop() would hide + * it from shrink_dcache_for_unmount(), leading to busy + * inodes on unmount and further oopses. + */ + if (IS_ROOT(dentry)) goto out_valid; } /* If we have submounts, don't unhash ! */