From 95fdacda55af950b4a1f5683bc7e0245dc7281aa Mon Sep 17 00:00:00 2001 From: Pavel Shilovsky Date: Thu, 26 Sep 2019 12:31:20 -0700 Subject: [PATCH] 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: Signed-off-by: Pavel Shilovsky Signed-off-by: Steve French Reviewed-by: Ronnie Sahlberg Signed-off-by: Greg Kroah-Hartman --- fs/cifs/smb2ops.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 58a502e622aa..951c444d83e7 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -1975,6 +1975,11 @@ 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");