When the final cifsFileInfo_put() is called from cifsiod and an oplock
break work is queued, lockdep complains loudly:
=============================================
[ INFO: possible recursive locking detected ]
4.11.0+ #21 Not tainted
---------------------------------------------
kworker/0:2/78 is trying to acquire lock:
("cifsiod"){++++.+}, at: flush_work+0x215/0x350
but task is already holding lock:
("cifsiod"){++++.+}, at: process_one_work+0x255/0x8e0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock("cifsiod");
lock("cifsiod");
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by kworker/0:2/78:
#0: ("cifsiod"){++++.+}, at: process_one_work+0x255/0x8e0
#1: ((&wdata->work)){+.+...}, at: process_one_work+0x255/0x8e0
stack backtrace:
CPU: 0 PID: 78 Comm: kworker/0:2 Not tainted 4.11.0+ #21
Workqueue: cifsiod cifs_writev_complete
Call Trace:
dump_stack+0x85/0xc2
__lock_acquire+0x17dd/0x2260
? match_held_lock+0x20/0x2b0
? trace_hardirqs_off_caller+0x86/0x130
? mark_lock+0xa6/0x920
lock_acquire+0xcc/0x260
? lock_acquire+0xcc/0x260
? flush_work+0x215/0x350
flush_work+0x236/0x350
? flush_work+0x215/0x350
? destroy_worker+0x170/0x170
__cancel_work_timer+0x17d/0x210
? ___preempt_schedule+0x16/0x18
cancel_work_sync+0x10/0x20
cifsFileInfo_put+0x338/0x7f0
cifs_writedata_release+0x2a/0x40
? cifs_writedata_release+0x2a/0x40
cifs_writev_complete+0x29d/0x850
? preempt_count_sub+0x18/0xd0
process_one_work+0x304/0x8e0
worker_thread+0x9b/0x6a0
kthread+0x1b2/0x200
? process_one_work+0x8e0/0x8e0
? kthread_create_on_node+0x40/0x40
ret_from_fork+0x31/0x40
This is a real warning. Since the oplock is queued on the same
workqueue this can deadlock if there is only one worker thread active
for the workqueue (which will be the case during memory pressure when
the rescuer thread is handling it).
Furthermore, there is at least one other kind of hang possible due to
the oplock break handling if there is only worker. (This can be
reproduced without introducing memory pressure by having passing 1 for
the max_active parameter of cifsiod.) cifs_oplock_break() can wait
indefintely in the filemap_fdatawait() while the cifs_writev_complete()
work is blocked:
sysrq: SysRq : Show Blocked State
task PC stack pid father
kworker/0:1 D 0 16 2 0x00000000
Workqueue: cifsiod cifs_oplock_break
Call Trace:
__schedule+0x562/0xf40
? mark_held_locks+0x4a/0xb0
schedule+0x57/0xe0
io_schedule+0x21/0x50
wait_on_page_bit+0x143/0x190
? add_to_page_cache_lru+0x150/0x150
__filemap_fdatawait_range+0x134/0x190
? do_writepages+0x51/0x70
filemap_fdatawait_range+0x14/0x30
filemap_fdatawait+0x3b/0x40
cifs_oplock_break+0x651/0x710
? preempt_count_sub+0x18/0xd0
process_one_work+0x304/0x8e0
worker_thread+0x9b/0x6a0
kthread+0x1b2/0x200
? process_one_work+0x8e0/0x8e0
? kthread_create_on_node+0x40/0x40
ret_from_fork+0x31/0x40
dd D 0 683 171 0x00000000
Call Trace:
__schedule+0x562/0xf40
? mark_held_locks+0x29/0xb0
schedule+0x57/0xe0
io_schedule+0x21/0x50
wait_on_page_bit+0x143/0x190
? add_to_page_cache_lru+0x150/0x150
__filemap_fdatawait_range+0x134/0x190
? do_writepages+0x51/0x70
filemap_fdatawait_range+0x14/0x30
filemap_fdatawait+0x3b/0x40
filemap_write_and_wait+0x4e/0x70
cifs_flush+0x6a/0xb0
filp_close+0x52/0xa0
__close_fd+0xdc/0x150
SyS_close+0x33/0x60
entry_SYSCALL_64_fastpath+0x1f/0xbe
Showing all locks held in the system:
2 locks held by kworker/0:1/16:
#0: ("cifsiod"){.+.+.+}, at: process_one_work+0x255/0x8e0
#1: ((&cfile->oplock_break)){+.+.+.}, at: process_one_work+0x255/0x8e0
Showing busy workqueues and worker pools:
workqueue cifsiod: flags=0xc
pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1
in-flight: 16:cifs_oplock_break
delayed: cifs_writev_complete, cifs_echo_request
pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=0s workers=3 idle: 750 3
Fix these problems by creating a a new workqueue (with a rescuer) for
the oplock break work.
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Steve French <smfrench@gmail.com>
CC: Stable <stable@vger.kernel.org>
A signal can interrupt a SendReceive call which result in incoming
responses to the call being ignored. This is a problem for calls such as
open which results in the successful response being ignored. This
results in an open file resource on the server.
The patch looks into responses which were cancelled after being sent and
in case of successful open closes the open fids.
For this patch, the check is only done in SendReceive2()
RH-bz: 1403319
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Cc: Stable <stable@vger.kernel.org>
In order to support compounding and encryption we need to separate
RFC1001 length field and SMB2 header structure because the protocol
treats them differently. This change will allow to simplify parsing
of such complex SMB2 packets further.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Remove the global file_list_lock to simplify cifs/smb3 locking and
have spinlocks that more closely match the information they are
protecting.
Add new tcon->open_file_lock and file->file_info_lock spinlocks.
Locks continue to follow a heirachy,
cifs_socket --> cifs_ses --> cifs_tcon --> cifs_file
where global tcp_ses_lock still protects socket and cifs_ses, while the
the newer locks protect the lower level structure's information
(tcon and cifs_file respectively).
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <steve.french@primarydata.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>
that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Coverity reports a warning for referencing the beginning of the
SMB2/SMB3 frame using the ProtocolId field as an array. Although
it works the same either way, this patch should quiet the warning
and might be a little clearer.
Reported by Coverity (CID 741269)
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
We have encountered failures when When testing smb2 mounts on ppc64
machines when using both Samba as well as Windows 2012.
On poking around, the problem was determined to be caused by the
high endian MessageID passed in the header for smb2. On checking the
corresponding MID for smb1 is converted to LE before being sent on the
wire.
We have tested this patch successfully on a ppc64 machine.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Replace all __constant_foo to foo() except in smb2status.h (1700 lines to
update).
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Steve French <sfrench@samba.org>
Cc: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The previous patch allowed remapping reserved characters from directory
listenings, this patch adds conversion the other direction, allowing
opening of files with any of the seven reserved characters.
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
response
Writes fail to Mac servers with SMB2.1 mounts (works with cifs though) due
to them sending an incorrect RFC1001 length for the SMB2.1 Write response.
Workaround this problem. MacOS server sends a write response with 3 bytes
of pad beyond the end of the SMB itself. The RFC1001 length is 3 bytes
more than the sum of the SMB2.1 header length + the write reponse.
Incorporate feedback from Jeff and JRA to allow servers to send
a tcp frame that is even more than three bytes too long
(ie much longer than the SMB2/SMB3 request that it contains) but
we do log it once now. In the earlier version of the patch I had
limited how far off the length field could be before we fail the request.
Signed-off-by: Steve French <smfrench@gmail.com>
Joe Perches and Hans Wennborg noticed that various places in the
kernel were printing decimal numbers with 0x prefix.
printk("0x%d") or equivalent
This fixes the instances of this in the cifs driver.
CC: Hans Wennborg <hans@hanshq.net>
CC: Joe Perches <joe@perches.com>
Signed-off-by: Steve French <smfrench@gmail.com>
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.
Cc: stable@vger.kernel.org
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>
that force a client to purge cache pages when a server requests it.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
that prepare the code to handle different types of SMB2 leases.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
If a server sends a lease break to a connection that doesn't have
opens with a lease key specified in the server response, we can't
find an open file to send an ack. Fix this by walking through
all connections we have.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
This happens when we receive a lease break from a server, then
find an appropriate lease key in opened files and schedule the
oplock_break slow work. lw pointer isn't freed in this case.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
that allows to access files through symlink created on a server.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
This worker function is needed to send SMB2 fsctl
(and ioctl) requests including:
validating negotiation info (secure negotiate)
querying the servers network interfaces
copy offload (refcopy)
Followon patches for the above three will use this.
This patch also does general validation of the response.
In the future, as David Disseldorp notes, for the copychunk ioctl
case, we will want to enhance the response processing to allow
returning the chunk request limits to the caller (even
though the server returns an error, in that case we would
return data that the caller could use - see 2.2.32.1).
See MS-SMB2 Section 2.2.31 for more details on format of fsctl.
Acked-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>
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 <joe@perches.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Some trivial endian fixes for the SMB2 code. One
warning remains which I asked Pavel to look at.
Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>
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 <pshilovsky@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
that needs for a successful mount through SMB2 protocol.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>
and add negotiate request type to let set_credits know that
we are only on negotiate stage and no need to make a decision
about disabling echos and oplocks.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>
Now we can process SMB2 messages: check message, get message id
and wakeup awaiting routines.
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <smfrench@gmail.com>
