Commit cd156549 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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[PATCH] knfsd: nfsd: oops exporting nonexistent directory

Export a directory that does not exist:
	exportfs -orw,fsid=0,insecure,no_subtree_check client:/home/NFS4

Try to mount from client with nfs4. Mount hangs (I'm not sure why -
that's another issue).

While client is hung, back on server

	mkdir /home/NFS4

The server panics in dput.  I traced the problem back to svc_export_parse()
calling path_release() even though path_lookup() failed (it happens to fill in
the nameidata structure with a negative dentry - so the test after out:

After patching, an recreating the problem, the client mount still takes some
time before finally exiting with a message "couldn't read superblock".

Here is a simple patch to resolve this issue:
Signed-off-by: default avatarFrank Filz <>
Signed-off-by: default avatarJ. Bruce Fields <>
Signed-off-by: default avatarNeil Brown <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent b5872b0d
......@@ -422,7 +422,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
goto out;
err = path_lookup(buf, 0, &nd);
if (err) goto out;
if (err) goto out_no_path;
exp.h.flags = 0;
exp.ex_client = dom;
......@@ -475,6 +475,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
if (nd.dentry)
if (dom)
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