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authorJ. Bruce Fields <bfields@redhat.com>2013-10-15 17:03:16 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2013-10-28 19:19:19 -0400
commita3f432bfd06a4ec3b812e32d3266e0d1ad75d008 (patch)
tree0e360753066b9dc61df85b2c5234f544ff418527 /fs/nfs
parent9d3a2260f0f4bd6379b0a0f131c743fff25b0029 (diff)
downloadop-kernel-dev-a3f432bfd06a4ec3b812e32d3266e0d1ad75d008.zip
op-kernel-dev-a3f432bfd06a4ec3b812e32d3266e0d1ad75d008.tar.gz
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 <bfields@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/dir.c8
1 files changed, 7 insertions, 1 deletions
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 ! */
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