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authorPavel Shilovsky <pshilov@microsoft.com>2019-09-26 12:31:20 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-10-05 15:12:37 +0200
commit4e679ab4b95aee9eae6f6a2fc60b9072389d6fb7 (patch)
treed0bc5e2a84dc6391e7a7017b74c62a19b5c938bc
parent9ea37d18a5bbedea0c65fcfa7c97ddec13ea618b (diff)
CIFS: Fix oplock handling for SMB 2.1+ protocols
commit a016e2794fc3a245a91946038dd8f34d65e53cc3 upstream. There may be situations when a server negotiates SMB 2.1 protocol version or higher but responds to a CREATE request with an oplock rather than a lease. Currently the client doesn't handle such a case correctly: when another CREATE comes in the server sends an oplock break to the initial CREATE and the client doesn't send an ack back due to a wrong caching level being set (READ instead of RWH). Missing an oplock break ack makes the server wait until the break times out which dramatically increases the latency of the second CREATE. Fix this by properly detecting oplocks when using SMB 2.1 protocol version and higher. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/cifs/smb2ops.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 249417924735..7e8e8826c26f 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3301,6 +3301,11 @@ smb21_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
if (oplock == SMB2_OPLOCK_LEVEL_NOCHANGE)
return;
+ /* Check if the server granted an oplock rather than a lease */
+ if (oplock & SMB2_OPLOCK_LEVEL_EXCLUSIVE)
+ return smb2_set_oplock_level(cinode, oplock, epoch,
+ purge_cache);
+
if (oplock & SMB2_LEASE_READ_CACHING_HE) {
new_oplock |= CIFS_CACHE_READ_FLG;
strcat(message, "R");