From e576bf5310bc9de9686a71539e9a1b60b4fba5cc Mon Sep 17 00:00:00 2001 From: Volker Lendecke Date: Tue, 25 Sep 2012 11:37:33 -0700 Subject: [PATCH] s3: Fix opening a file under kernel oplocks With the prior code we assumed that we do not have kernel oplocks around when we open a file because we handled samba-internal oplock breaks before the open attempt. Autobuild-User(master): Volker Lendecke Autobuild-Date(master): Sat Sep 29 19:29:36 CEST 2012 on sn-devel-104 --- source3/smbd/open.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) diff --git a/source3/smbd/open.c b/source3/smbd/open.c index 0f34992454b..d4babd40f7d 100644 --- a/source3/smbd/open.c +++ b/source3/smbd/open.c @@ -1929,6 +1929,7 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn, bool def_acl = False; bool posix_open = False; bool new_file_created = False; + bool first_open_attempt = true; NTSTATUS fsp_open = NT_STATUS_ACCESS_DENIED; mode_t new_unx_mode = (mode_t)0; mode_t unx_mode = (mode_t)0; @@ -2035,6 +2036,8 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn, /* Ensure we don't reprocess this message. */ remove_deferred_open_message_smb(req->sconn, req->mid); + + first_open_attempt = false; } } @@ -2191,6 +2194,24 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn, flags2 &= ~(O_CREAT|O_TRUNC); } + if (first_open_attempt && lp_kernel_oplocks(SNUM(conn))) { + /* + * With kernel oplocks the open breaking an oplock + * blocks until the oplock holder has given up the + * oplock or closed the file. We prevent this by first + * trying to open the file with O_NONBLOCK (see "man + * fcntl" on Linux). For the second try, triggered by + * an oplock break response, we do not need this + * anymore. + * + * This is true under the assumption that only Samba + * requests kernel oplocks. Once someone else like + * NFSv4 starts to use that API, we will have to + * modify this by communicating with the NFSv4 server. + */ + flags2 |= O_NONBLOCK; + } + /* * Ensure we can't write on a read-only share or file. */ @@ -2239,6 +2260,64 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn, flags|flags2, unx_mode, access_mask, open_access_mask, &new_file_created); + if (NT_STATUS_EQUAL(fsp_open, NT_STATUS_NETWORK_BUSY)) { + struct deferred_open_record state; + + /* + * EWOULDBLOCK/EAGAIN maps to NETWORK_BUSY. + */ + if (file_existed && S_ISFIFO(fsp->fsp_name->st.st_ex_mode)) { + DEBUG(10, ("FIFO busy\n")); + return NT_STATUS_NETWORK_BUSY; + } + if (req == NULL) { + DEBUG(10, ("Internal open busy\n")); + return NT_STATUS_NETWORK_BUSY; + } + + /* + * From here on we assume this is an oplock break triggered + */ + + lck = get_existing_share_mode_lock(talloc_tos(), fsp->file_id); + if (lck == NULL) { + state.delayed_for_oplocks = false; + state.async_open = false; + state.id = fsp->file_id; + defer_open(NULL, request_time, timeval_set(0, 0), + req, &state); + DEBUG(10, ("No share mode lock found after " + "EWOULDBLOCK, retrying sync\n")); + return NT_STATUS_SHARING_VIOLATION; + } + + find_oplock_types(fsp, 0, lck, &batch_entry, &exclusive_entry, + &got_level2_oplock, &got_a_none_oplock); + + if (delay_for_batch_oplocks(fsp, req->mid, 0, batch_entry) || + delay_for_exclusive_oplocks(fsp, req->mid, 0, + exclusive_entry)) { + schedule_defer_open(lck, request_time, req); + TALLOC_FREE(lck); + DEBUG(10, ("Sent oplock break request to kernel " + "oplock holder\n")); + return NT_STATUS_SHARING_VIOLATION; + } + + /* + * No oplock from Samba around. Immediately retry with + * a blocking open. + */ + state.delayed_for_oplocks = false; + state.async_open = false; + state.id = lck->data->id; + defer_open(lck, request_time, timeval_set(0, 0), req, &state); + TALLOC_FREE(lck); + DEBUG(10, ("No Samba oplock around after EWOULDBLOCK. " + "Retrying sync\n")); + return NT_STATUS_SHARING_VIOLATION; + } + if (!NT_STATUS_IS_OK(fsp_open)) { if (NT_STATUS_EQUAL(fsp_open, NT_STATUS_RETRY)) { schedule_async_open(request_time, req); -- 2.11.4.GIT