[PATCH v2] nfsd: depend on CRYPTO_MD5 for legacy client tracking

[Patrick Steinhardt <ps@pks.im>]

The legacy client tracking infrastructure of nfsd makes use of MD5 to
derive a client's recovery directory name. As the nfsd module doesn't
declare any dependency on CRYPTO_MD5, though, it may fail to allocate
the hash if the kernel was compiled without it. As a result, generation
of client recovery directories will fail with the following error:

    NFSD: unable to generate recoverydir name

The explicit dependency on CRYPTO_MD5 was removed as redundant back in
6aaa67b5f3b9 (NFSD: Remove redundant "select" clauses in fs/Kconfig
2008-02-11) as it was already implicitly selected via RPCSEC_GSS_KRB5.
This broke when RPCSEC_GSS_KRB5 was made optional for NFSv4 in commit
df486a25900f (NFS: Fix the selection of security flavours in Kconfig) at
a later point.

Fix the issue by adding back an explicit dependency on CRYPTO_MD5.

Fixes: df486a25900f (NFS: Fix the selection of security flavours in Kconfig)
Signed-off-by: Patrick Steinhardt <ps@pks.im>
---

The only change compared to v1 is in the commit message. As
pointed out by Chuck, it wasn't actually commit 6aaa67b5f3b9
which broke it, but the later df486a25900f. I've reworded the
commit message and fixed the Fixes tag to account for that.

 fs/nfsd/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
index c4b1a89b8845..f2f81561ebb6 100644
--- a/fs/nfsd/Kconfig
+++ b/fs/nfsd/Kconfig
@@ -73,6 +73,7 @@ config NFSD_V4
 	select NFSD_V3
 	select FS_POSIX_ACL
 	select SUNRPC_GSS
+	select CRYPTO_MD5
 	select CRYPTO_SHA256
 	select GRACE_PERIOD
 	help
-- 
2.24.0