cifs_tcp_ses_lock is a rwlock with protects the cifs_tcp_ses_list,
server->smb_ses_list and the ses->tcon_list. It also protects a few
ref counters in server, ses and tcon. In most cases the critical section
doesn't seem to be large, in a few cases where it is slightly large, there
seem to be really no benefit from concurrent access. I briefly considered RCU
mechanism but it appears to me that there is no real need.
Replace it with a spinlock and get rid of the last rwlock in the cifs code.
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Start calculation auth response within a session. Move/Add pertinet
data structures like session key, server challenge and ntlmv2_hash in
a session structure. We should do the calculations within a session
before copying session key and response over to server data
structures because a session setup can fail.
Only after a very first smb session succeeds, it copies/makes its
session key, session key of smb connection. This key stays with
the smb connection throughout its life.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Create a workqueue job that cleans out unused tlinks. For now, it uses
a hardcoded expire time of 10 minutes. When it's done, the work rearms
itself. On umount, the work is cancelled before tearing down the tlink
tree.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This allows someone to declare a mount as a multiuser mount.
Multiuser mounts also imply "noperm" since we want to allow the server
to handle permission checking. It also (for now) requires Kerberos
authentication. Eventually, we could expand this to other authtypes, but
that requires a scheme to allow per-user credential stashing in some
form.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This patch is rather large, but it's a bit difficult to do piecemeal...
For non-multiuser mounts, everything will basically work as it does
today. A call to cifs_sb_tlink will return the "master" tcon link.
Turn the tcon pointer in the cifs_sb into a radix tree that uses the
fsuid of the process as a key. The value is a new "tcon_link" struct
that contains info about a tcon that's under construction.
When a new process needs a tcon, it'll call cifs_sb_tcon. That will
then look up the tcon_link in the radix tree. If it exists and is
valid, it's returned.
If it doesn't exist, then we stuff a new tcon_link into the tree and
mark it as pending and then go and try to build the session/tcon.
If that works, the tcon pointer in the tcon_link is updated and the
pending flag is cleared.
If the construction fails, then we set the tcon pointer to an ERR_PTR
and clear the pending flag.
If the radix tree is searched and the tcon_link is marked pending
then we go to sleep and wait for the pending flag to be cleared.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
At mount time, we'll always need to create a tcon that will serve as a
template for others that are associated with the mount. This tcon is
known as the "master" tcon.
In some cases, we'll need to use that tcon regardless of who's accessing
the mount. Add an accessor function for the master tcon and go ahead and
switch the appropriate places to use it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
When we convert cifs to do multiple sessions per mount, we'll need more
than one tcon per superblock. At that point "cifs_sb->tcon" will make
no sense. Add a new accessor function that gets a tcon given a cifs_sb.
For now, it just returns cifs_sb->tcon. Later it'll do more.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
If registering fs cache failed, we weren't cleaning up proc.
Acked-by: Jeff Layton <jlayton@redhat.com>
CC: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
With commit 7332f2a621, cifsd will no
longer exit when the socket abends and the tcpStatus is CifsNew. With
that change, there's no reason to avoid matching an existing session in
this state.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
When using multi-homed machines, it's nice to be able to specify
the local IP to use for outbound connections. This patch gives
cifs the ability to bind to a particular IP address.
Usage: mount -t cifs -o srcaddr=192.168.1.50,user=foo, ...
Usage: mount -t cifs -o srcaddr=2002:💯1,user=foo, ...
Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Dr. David Holder <david.holder@erion.co.uk>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Attribue Value (AV) pairs or Target Info (TI) pairs are part of
ntlmv2 authentication.
Structure ntlmv2_resp had only definition for two av pairs.
So removed it, and now allocation of av pairs is dynamic.
For servers like Windows 7/2008, av pairs sent by server in
challege packet (type 2 in the ntlmssp exchange/negotiation) can
vary.
Server sends them during ntlmssp negotiation. So when ntlmssp is used
as an authentication mechanism, type 2 challenge packet from server
has this information. Pluck it and use the entire blob for
authenticaiton purpose. If user has not specified, extract
(netbios) domain name from the av pairs which is used to calculate
ntlmv2 hash. Servers like Windows 7 are particular about the AV pair
blob.
Servers like Windows 2003, are not very strict about the contents
of av pair blob used during ntlmv2 authentication.
So when security mechanism such as ntlmv2 is used (not ntlmv2 in ntlmssp),
there is no negotiation and so genereate a minimal blob that gets
used in ntlmv2 authentication as well as gets sent.
Fields tilen and tilbob are session specific. AV pair values are defined.
To calculate ntlmv2 response we need ti/av pair blob.
For sec mech like ntlmssp, the blob is plucked from type 2 response from
the server. From this blob, netbios name of the domain is retrieved,
if user has not already provided, to be included in the Target String
as part of ntlmv2 hash calculations.
For sec mech like ntlmv2, create a minimal, two av pair blob.
The allocated blob is freed in case of error. In case there is no error,
this blob is used in calculating ntlmv2 response (in CalcNTLMv2_response)
and is also copied on the response to the server, and then freed.
The type 3 ntlmssp response is prepared on a buffer,
5 * sizeof of struct _AUTHENTICATE_MESSAGE, an empirical value large
enough to hold _AUTHENTICATE_MESSAGE plus a blob with max possible
10 values as part of ntlmv2 response and lmv2 keys and domain, user,
workstation names etc.
Also, kerberos gets selected as a default mechanism if server supports it,
over the other security mechanisms.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
cifs_get_smb_ses must be called on a server pointer on which it holds an
active reference. It first does a search for an existing SMB session. If
it finds one, it'll put the server reference and then try to ensure that
the negprot is done, etc.
If it encounters an error at that point then it'll return an error.
There's a potential problem here though. When cifs_get_smb_ses returns
an error, the caller will also put the TCP server reference leading to a
double-put.
Fix this by having cifs_get_smb_ses only put the server reference if
it found an existing session that it could use and isn't returning an
error.
Cc: stable@kernel.org
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
cifs_demultiplex_thread sets the addr.sockAddr.sin_port without any
regard for the socket family. While it may be that the error in question
here never occurs on an IPv6 socket, it's probably best to be safe and
set the port properly if it ever does.
Break the port setting code out of cifs_fill_sockaddr and into a new
function, and call that from cifs_demultiplex_thread.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
If the tcpStatus is still CifsNew, the main cifs_demultiplex_loop can
break out prematurely in some cases. This is wrong as we will almost
always have other structures with pointers to the TCP_Server_Info. If
the main loop breaks under any other condition other than tcpStatus ==
CifsExiting, then it'll face a use-after-free situation.
I don't see any reason to treat a CifsNew tcpStatus differently than
CifsGood. I believe we'll still want to attempt to reconnect in either
case. What should happen in those situations is that the MIDs get marked
as MID_RETRY_NEEDED. This will make CIFSSMBNegotiate return -EAGAIN, and
then the caller can retry the whole thing on a newly reconnected socket.
If that fails again in the same way, the caller of cifs_get_smb_ses
should tear down the TCP_Server_Info struct.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
When cifs_demultiplex_thread exits, it does a number of cleanup tasks
including freeing the TCP_Server_Info struct. Much of the existing code
in cifs assumes that when there is a cisfSesInfo struct, that it holds a
reference to a valid TCP_Server_Info struct.
We can never allow cifsd to exit when a cifsSesInfo struct is still
holding a reference to the server. The server pointers will then point
to freed memory.
This patch eliminates a couple of questionable conditions where it does
this. The idea here is to make an -EINTR return from kernel_recvmsg
behave the same way as -ERESTARTSYS or -EAGAIN. If the task was
signalled from cifs_put_tcp_session, then tcpStatus will be CifsExiting,
and the kernel_recvmsg call will return quickly.
There's also another condition where this can occur too -- if the
tcpStatus is still in CifsNew, then it will also exit if the server
closes the socket prematurely. I think we'll probably also need to fix
that situation, but that requires a bit more consideration.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This reverts commit 9fbc590860.
The change to kernel crypto and fixes to ntlvm2 and ntlmssp
series, introduced a regression. Deferring this patch series
to 2.6.37 after Shirish fixes it.
Signed-off-by: Steve French <sfrench@us.ibm.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
CC: Shirish Pargaonkar <shirishp@us.ibm.com>
It's possible for a cifsSesInfo struct to have a NULL password, so we
need to check for that prior to running strncmp on it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Make ntlmv2 as an authentication mechanism within ntlmssp
instead of ntlmv1.
Parse type 2 response in ntlmssp negotiation to pluck
AV pairs and use them to calculate ntlmv2 response token.
Also, assign domain name from the sever response in type 2
packet of ntlmssp and use that (netbios) domain name in
calculation of response.
Enable cifs/smb signing using rc4 and md5.
Changed name of the structure mac_key to session_key to reflect
the type of key it holds.
Use kernel crypto_shash_* APIs instead of the equivalent cifs functions.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steve French <sfrench@us.ibm.com>
cifs_find_smb_ses assumes that the vol->password field is a valid
pointer, but that's only the case if a password was passed in via
the options string. It's possible that one won't be if there is
no mount helper on the box.
Reported-by: diabel <gacek-2004@wp.pl>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Make cifs_convert_address() take a const src pointer and a length so that all
the strlen() calls in their can be cut out and to make it unnecessary to modify
the src string.
Also return the data length from dns_resolve_server_name_to_ip() so that a
strlen() can be cut out of cifs_compose_mount_options() too.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
I'm not sure why this was merged with this flag hardcoded on, but it
seems quite dangerous. Turn it off.
Also, mount.cifs hands unrecognized options off to the kernel so there
should be no need for changes there in order to support this.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
These are all handled by the userspace mount programs, but older versions
of mount.cifs also handed them off to the kernel. Ignore them.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Doh, fix a use after free bug.
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Reviewed-and-Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Right now, there's no clear separation between the uid that owns the
credentials used to do the mount and the overriding owner of the files
on that mount.
Add a separate cred_uid field that is set to the real uid
of the mount user. Unlike the linux_uid, the uid= option does not
override this parameter. The parm is sent to cifs.upcall, which can then
preferentially use the creduid= parm instead of the uid= parm for
finding credentials.
This is not the only way to solve this. We could try to do all of this
in kernel instead by having a module parameter that affects what gets
passed in the uid= field of the upcall. That said, we have a lot more
flexibility to change things in userspace so I think it probably makes
sense to do it this way.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Add a mount option 'fsc' to enable local caching on CIFS.
I considered adding a separate debug bit for caching, but it appears that
debugging would be relatively easier with the normal CIFS_INFO level.
As the cifs-utils (userspace) changes are not done yet, this patch enables
'fsc' by default to enable testing.
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Define superblock-level cache index objects (managed by cifsTconInfo structs).
Each superblock object is created in a server-level index object and in itself
an index into which inode-level objects are inserted.
The superblock object is keyed by sharename. The UniqueId/IndexNumber is used to
validate that the exported share is the same since we accessed it last time.
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This patch replaces the earlier patch by the same name. The only
difference is that MAX_PASSWORD_SIZE has been increased to attempt to
match the limits that windows enforces.
Do a better job of matching sessions by authtype. Matching by username
for a Kerberos session is incorrect, and anonymous sessions need special
handling.
Also, in the case where we do match by username, we also need to match
by password. That ensures that someone else doesn't "borrow" an existing
session without needing to know the password.
Finally, passwords can be longer than 16 bytes. Bump MAX_PASSWORD_SIZE
to 512 to match the size that the userspace mount helper allows.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
The secType is a per-tcp session entity, but the current routine doesn't
verify that it is acceptible when attempting to match an existing TCP
session.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Move the address comparator out of cifs_find_tcp_session and into a
separate function for cleanliness. Also change the argument to
that function to a "struct sockaddr" pointer. Passing pointers to
sockaddr_storage is a little odd since that struct is generally for
declaring static storage.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This patch should replace the patch I sent a couple of weeks ago to
set the port in cifs_convert_address.
Currently we set this in cifs_find_tcp_session, but that's more of a
side effect than anything. Add a new function called cifs_fill_sockaddr.
Have it call cifs_convert_address and then set the port.
This also allows us to skip passing in the port as a separate parm to
cifs_find_tcp_session.
Also, change cifs_convert_address take a struct sockaddr * rather than
void * to make it clearer how this function should be called.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Define server-level cache index objects (as managed by TCP_ServerInfo structs)
and register then with FS-Cache. Each server object is created in the CIFS
top-level index object and is itself an index into which superblock-level
objects are inserted.
The server objects are now keyed by {IPaddress,family,port} tuple.
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
So that we can reasonably set up the secType based on both the
NegotiateProtocol response and the parsed mount options.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
We can use the is_first_ses_reconnect() function to determine this.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This is a typo, if pvolume_info were NULL it would oops.
This function is used in clean up and error handling. The current code
never passes a NULL pvolume_info, but it could pass a NULL *pvolume_info
if the kmalloc() failed.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
...since that more accurately describes what that variable holds.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
...it's mostly part of cifs_mount. Break it out into a separate
function.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Add a local_nls field to the smb_vol struct and keep a pointer to the
local_nls in it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Neaten cERROR and cFYI macros, reduce text space
~2.5K
Convert '__FILE__ ": " fmt' to '"%s: " fmt', __FILE__' to save text space
Surround macros with do {} while
Add parentheses to macros
Make statement expression macro from macro with assign
Remove now unnecessary parentheses from cFYI and cERROR uses
defconfig with CIFS support old
$ size fs/cifs/built-in.o
text data bss dec hex filename
156012 1760 148 157920 268e0 fs/cifs/built-in.o
defconfig with CIFS support old
$ size fs/cifs/built-in.o
text data bss dec hex filename
153508 1760 148 155416 25f18 fs/cifs/built-in.o
allyesconfig old:
$ size fs/cifs/built-in.o
text data bss dec hex filename
309138 3864 74824 387826 5eaf2 fs/cifs/built-in.o
allyesconfig new
$ size fs/cifs/built-in.o
text data bss dec hex filename
305655 3864 74824 384343 5dd57 fs/cifs/built-in.o
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
convert it to a real mutex.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
mount option sockopt=TCP_NODELAY helpful for faster networks
boosting performance. Kernel bugzilla bug number 14032.
Signed-off-by: Steve French <sfrench@us.ibm.com>
The scenario is this:
The kernel gets EREMOTE and starts chasing a DFS referral at mount time.
The tcon reference is put, which puts the session reference too, but
neither pointer is zeroed out.
The mount gets retried (goto try_mount_again) with new mount info.
Session setup fails fails and rc ends up being non-zero. The code then
falls through to the end and tries to put the previously freed tcon
pointer again. Oops at: cifs_put_smb_ses+0x14/0xd0
Fix this by moving the initialization of the rc variable and the tcon,
pSesInfo and srvTcp pointers below the try_mount_again label. Also, add
a FreeXid() before the goto to prevent xid "leaks".
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Gustavo Carvalho Homem <gustavo@angulosolido.pt>
CC: stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Because it's lighter weight, CIFS tries to use CIFSGetSrvInodeNumber to
verify the accessibility of the root inode and then falls back to doing a
full QPathInfo if that fails with -EOPNOTSUPP. I have at least a report
of a server that returns NT_STATUS_INTERNAL_ERROR rather than something
that translates to EOPNOTSUPP.
Rather than trying to be clever with that call, just have
is_path_accessible do a normal QPathInfo. That call is widely
supported and it shouldn't increase the overhead significantly.
Cc: Stable <stable@kernel.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This is the fourth respin of the patch to convert oplock breaks to
use the slow_work facility.
A customer of ours was testing a backport of one of the earlier
patchsets, and hit a "Busy inodes after umount..." problem. An oplock
break job had raced with a umount, and the superblock got torn down and
its memory reused. When the oplock break job tried to dereference the
inode->i_sb, the kernel oopsed.
This patchset has the oplock break job hold an inode and vfsmount
reference until the oplock break completes. With this, there should be
no need to take a tcon reference (the vfsmount implicitly holds one
already).
Currently, when an oplock break comes in there's a chance that the
oplock break job won't occur if the allocation of the oplock_q_entry
fails. There are also some rather nasty races in the allocation and
handling these structs.
Rather than allocating oplock queue entries when an oplock break comes
in, add a few extra fields to the cifsFileInfo struct. Get rid of the
dedicated cifs_oplock_thread as well and queue the oplock break job to
the slow_work thread pool.
This approach also has the advantage that the oplock break jobs can
potentially run in parallel rather than be serialized like they are
today.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
