kernel.git/fs/cifs/misc.c, branch linux-3.14.y

cifs: Wait for writebacks to complete before attempting write.

2014-05-31T20:20:29Z

commit c11f1df5003d534fd067f0168bfad7befffb3b5c upstream. Problem reported in Red Hat bz 1040329 for strict writes where we cache only when we hold oplock and write direct to the server when we don't. When we receive an oplock break, we first change the oplock value for the inode in cifsInodeInfo->oplock to indicate that we no longer hold the oplock before we enqueue a task to flush changes to the backing device. Once we have completed flushing the changes, we return the oplock to the server. There are 2 ways here where we can have data corruption 1) While we flush changes to the backing device as part of the oplock break, we can have processes write to the file. These writes check for the oplock, find none and attempt to write directly to the server. These direct writes made while we are flushing from cache could be overwritten by data being flushed from the cache causing data corruption. 2) While a thread runs in cifs_strict_writev, the machine could receive and process an oplock break after the thread has checked the oplock and found that it allows us to cache and before we have made changes to the cache. In that case, we end up with a dirty page in cache when we shouldn't have any. This will be flushed later and will overwrite all subsequent writes to the part of the file represented by this page. Before making any writes to the server, we need to confirm that we are not in the process of flushing data to the server and if we are, we should wait until the process is complete before we attempt the write. We should also wait for existing writes to complete before we process an oplock break request which changes oplock values. We add a version specific downgrade_oplock() operation to allow for differences in the oplock values set for the different smb versions. Signed-off-by: Sachin Prabhu Reviewed-by: Jeff Layton Reviewed-by: Pavel Shilovsky Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

cifs: Make big endian multiplex ID sequences monotonic on the wire

2013-11-02T17:51:53Z

The multiplex identifier (MID) in the SMB header is only ever used by the client, in conjunction with PID, to match responses from the server. As such, the endianess of the MID is not important. However, When tracing packet sequences on the wire, protocol analyzers such as wireshark display MID as little endian. It is much more informative for the on-the-wire MID sequences to match debug information emitted by the CIFS driver. Therefore, one should write and read MID in the SMB header assuming it is always little endian. Observed from wireshark during the protocol negotiation and session setup: Multiplex ID: 256 Multiplex ID: 256 Multiplex ID: 512 Multiplex ID: 512 Multiplex ID: 768 Multiplex ID: 768 After this patch on-the-wire MID values begin at 1 and increase monotonically. Introduce get_next_mid64() for the internal consumers that use the full 64 bit multiplex identifier. Introduce the helpers get_mid() and compare_mid() to make the endian translation clear. Reviewed-by: Jeff Layton Signed-off-by: Tim Gardner Signed-off-by: Steve French

cifs: Remove redundant multiplex identifier check from check_smb_hdr()

2013-10-28T14:31:36Z

The only call site for check_smb_header() assigns 'mid' from the SMB packet, which is then checked again in check_smb_header(). This seems like redundant redundancy. Reviewed-by: Jeff Layton Signed-off-by: Tim Gardner Signed-off-by: Steve French

CIFS: Replace clientCanCache* bools with an integer

2013-09-08T22:49:17Z

that prepare the code to handle different types of SMB2 leases. Signed-off-by: Pavel Shilovsky Signed-off-by: Steve French

cifs: Process post session setup code in respective dialect functions.

2013-09-08T19:47:47Z

Move the post (successful) session setup code to respective dialect routines. For smb1, session key is per smb connection. For smb2/smb3, session key is per smb session. If client and server do not require signing, free session key for smb1/2/3. If client and server require signing smb1 - Copy (kmemdup) session key for the first session to connection. Free session key of that and subsequent sessions on this connection. smb2 - For every session, keep the session key and free it when the session is being shutdown. smb3 - For every session, generate the smb3 signing key using the session key and then free the session key. There are two unrelated line formatting changes as well. Reviewed-by: Jeff Layton Signed-off-by: Shirish Pargaonkar Signed-off-by: Steve French

cifs: track the enablement of signing in the TCP_Server_Info

2013-06-24T06:56:43Z

Currently, we determine this according to flags in the sec_mode, flags in the global_secflags and via other methods. That makes the semantics very hard to follow and there are corner cases where we don't handle this correctly. Add a new bool to the TCP_Server_Info that acts as a simple flag to tell us whether signing is enabled on this connection or not, and fix up the places that need to determine this to use that flag. This is a bit weird for the SMB2 case, where signing is per-session. SMB2 needs work in this area already though. The existing SMB2 code has similar logic to what we're using here, so there should be no real change in behavior. These changes should make it easier to implement per-session signing in the future though. Signed-off-by: Jeff Layton Reviewed-by: Pavel Shilovsky Signed-off-by: Steve French

[CIFS] cifs: Rename cERROR and cFYI to cifs_dbg

2013-05-05T03:17:23Z

It's not obvious from reading the macro names that these macros are for debugging. Convert the names to a single more typical kernel style cifs_dbg macro. cERROR(1, ...) -> cifs_dbg(VFS, ...) cFYI(1, ...) -> cifs_dbg(FYI, ...) cFYI(DBG2, ...) -> cifs_dbg(NOISY, ...) Move the terminating format newline from the macro to the call site. Add CONFIG_CIFS_DEBUG function cifs_vfs_err to emit the "CIFS VFS: " prefix for VFS messages. Size is reduced ~ 1% when CONFIG_CIFS_DEBUG is set (default y) $ size fs/cifs/cifs.ko* text data bss dec hex filename 265245 2525 132 267902 4167e fs/cifs/cifs.ko.new 268359 2525 132 271016 422a8 fs/cifs/cifs.ko.old Other miscellaneous changes around these conversions: o Miscellaneous typo fixes o Add terminating \n's to almost all formats and remove them from the macros to be more kernel style like. A few formats previously had defective \n's o Remove unnecessary OOM messages as kmalloc() calls dump_stack o Coalesce formats to make grep easier, added missing spaces when coalescing formats o Use %s, __func__ instead of embedded function name o Removed unnecessary "cifs: " prefixes o Convert kzalloc with multiply to kcalloc o Remove unused cifswarn macro Signed-off-by: Joe Perches Signed-off-by: Jeff Layton Signed-off-by: Steve French

cifs: Convert struct cifs_sb_info to use kuids and kgids

2013-02-13T15:28:54Z

Cc: Steve French Signed-off-by: "Eric W. Biederman"

CIFS: Fix fast lease break after open problem

2012-09-25T02:46:33Z

Now we walk though cifsFileInfo's list for every incoming lease break and look for an equivalent there. That approach misses lease breaks that come just after an open response - we don't have time to populate new cifsFileInfo structure to the list. Fix this by adding new list of pending opens and look for a lease there if we didn't find it in the list of cifsFileInfo structures. Signed-off-by: Pavel Shilovsky Signed-off-by: Steve French

CIFS: Replace netfid with cifs_fid struct in cifsFileInfo

2012-09-25T02:46:26Z

This is help us to extend the code for future protocols that can use another fid mechanism (as SMB2 that has it divided into two parts: persistent and violatile). Also rename variables and refactor the code around the changes. Reviewed-by: Jeff Layton Signed-off-by: Pavel Shilovsky Signed-off-by: Steve French