Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 3.12 05/40] nfs: use IS_ROOT not DCACHE_DISCONNECTED | Date | Wed, 2 Apr 2014 22:12:51 +0200 |
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From: "J. Bruce Fields" <bfields@redhat.com>
3.12-stable review patch. If anyone has any objections, please let me know.
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commit a3f432bfd06a4ec3b812e32d3266e0d1ad75d008 upstream.
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 <bfields@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- fs/nfs/dir.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index e81a1cae81b5..d0325d7db643 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 ! */ -- 1.9.1
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