Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
as correctly noted at bug #12454. Someone can lookup entry with NULL
->owner, thus not pinning enything, and release it later resulting
in module refcount underflow.
We can keep ->owner and supply it at registration time like ->proc_fops
and ->data.
But this leaves ->owner as easy-manipulative field (just one C assignment)
and somebody will forget to unpin previous/pin current module when
switching ->owner. ->proc_fops is declared as "const" which should give
some thoughts.
->read_proc/->write_proc were just fixed to not require ->owner for
protection.
rmmod'ed directories will be empty and return "." and ".." -- no harm.
And directories with tricky enough readdir and lookup shouldn't be modular.
We definitely don't want such modular code.
Removing ->owner will also make PDE smaller.
So, let's nuke it.
Kudos to Jeff Layton for reminding about this, let's say, oversight.
http://bugzilla.kernel.org/show_bug.cgi?id=12454
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
simple_set_mnt() is defined as returning 'int' but always returns 0.
Callers assume simple_set_mnt() never fails and don't properly cleanup if
it were to _ever_ fail. For instance, get_sb_single() and get_sb_nodev()
should:
up_write(sb->s_unmount);
deactivate_super(sb);
if simple_set_mnt() fails.
Since simple_set_mnt() never fails, would be cleaner if it did not
return anything.
[akpm@linux-foundation.org: fix build]
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
CIFS can allocate a few bytes to little for the nativeFileSystem field
during tree connect response processing during mount. This can result
in a "Redzone overwritten" message to be logged.
Signed-off-by: Sridhar Vinay <vinaysridhar@in.ibm.com>
Acked-by: Shirish Pargaonkar <shirishp@us.ibm.com>
CC: Stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Samba server (version 3.3.1 and earlier, and 3.2.8 and earlier) incorrectly
required the O_CREAT flag on posix open (even when a file was not being
created). This disables posix open (create is still ok) after the first
attempt returns EINVAL (and logs an error, once, recommending that they
update their server).
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Discovered at Connnectathon 2009...
The buffer format byte and the pad are transposed in NT_RENAME calls
(which are used to set hardlinks). Most servers seem to ignore this
fact, but NetApp filers throw back an error due to this problem. This
patch fixes it.
CC: Stable <stable@kernel.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
There are about 60 fsctl calls which Windows claims would be able
to be sent remotely and handled by the server. This adds the #defines
for them. A few of them look immediately useful, but need to also
add the structure definitions for them so they can be sent as SMBs.
Signed-off-by: Steve French <sfrench@us.ibm.com>
Although attr == NULL can not happen, this makes cifs_set_file_info safer
in the future since it may not be obvious that the caller can not set
attr to NULL.
Signed-off-by: Steve French <sfrench@us.ibm.com>
If the network connection crashes, and we have to reopen files, preferentially
use the newer cifs posix open protocol operation if the server supports it.
Signed-off-by: Steve French <sfrench@us.ibm.com>
If this mount option is set, when an application does an
fsync call then the cifs client does not send an SMB Flush
to the server (to force the server to write all dirty data
for this file immediately to disk), although cifs still sends
all dirty (cached) file data to the server and waits for the
server to respond to the write write. Since SMB Flush can be
very slow, and some servers may be reliable enough (to risk
delaying slightly flushing the data to disk on the server),
turning on this option may be useful to improve performance for
applications that fsync too much, at a small risk of server
crash. If this mount option is not set, by default cifs will
send an SMB flush request (and wait for a response) on every
fsync call.
Signed-off-by: Steve French <sfrench@us.ibm.com>
In contrast to the now-obsolete smbfs, cifs does not send SMB_COM_FLUSH
in response to an explicit fsync(2) to guarantee that all volatile data
is written to stable storage on the server side, provided the server
honors the request (which, to my knowledge, is true for Windows and
Samba with 'strict sync' enabled).
This patch modifies the cifs_fsync implementation to restore the
fsync-behavior of smbfs by triggering SMB_COM_FLUSH after sending
outstanding data on the client side to the server.
Signed-off-by: Horst Reiterer <horst.reiterer@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
When two different users mount the same Windows 2003 Server share using CIFS,
the first session mounted can be invalidated. Some servers invalidate the first
smb session when a second similar user (e.g. two users who get mapped by server to "guest")
authenticates an smb session from the same client.
By making sure that we set the 2nd and subsequent vc numbers to nonzero values,
this ensures that we will not have this problem.
Fixes Samba bug 6004, problem description follows:
How to reproduce:
- configure an "open share" (full permissions to Guest user) on Windows 2003
Server (I couldn't reproduce the problem with Samba server or Windows older
than 2003)
- mount the share twice with different users who will be authenticated as guest.
noacl,noperm,user=john,dir_mode=0700,domain=DOMAIN,rw
noacl,noperm,user=jeff,dir_mode=0700,domain=DOMAIN,rw
Result:
- just the mount point mounted last is accessible:
Signed-off-by: Steve French <sfrench@us.ibm.com>
Samba server added support for a new posix open/create/mkdir operation
a year or so ago, and we added support to cifs for mkdir to use it,
but had not added the corresponding code to file create.
The following patch helps improve the performance of the cifs create
path (to Samba and servers which support the cifs posix protocol
extensions). Using Connectathon basic test1, with 2000 files, the
performance improved about 15%, and also helped reduce network traffic
(17% fewer SMBs sent over the wire) due to saving a network round trip
for the SetPathInfo on every file create.
It should also help the semantics (and probably the performance) of
write (e.g. when posix byte range locks are on the file) on file
handles opened with posix create, and adds support for a few flags
which would have to be ignored otherwise.
Signed-off-by: Steve French <sfrench@us.ibm.com>
Fixes kernel bug #10451http://bugzilla.kernel.org/show_bug.cgi?id=10451
Certain NAS appliances do not set the operating system or network operating system
fields in the session setup response on the wire. cifs was oopsing on the unexpected
zero length response fields (when trying to null terminate a zero length field).
This fixes the oops.
Acked-by: Jeff Layton <jlayton@redhat.com>
CC: stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
...if it does then we pass a pointer to an unintialized variable for
the inode number to cifs_new_inode. Have it pass a NULL pointer instead.
Also tweak the function prototypes to reduce the amount of casting.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Move new inode creation into a separate routine and refactor the
callers to take advantage of it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Fixes OOPs with message 'kernel BUG at fs/cifs/cifs_dfs_ref.c:274!'.
Checks if the prefixpath in an accesible while we are still in cifs_mount
and fails with reporting a error if we can't access the prefixpath
Should fix Samba bugs 6086 and 5861 and kernel bug 12192
Signed-off-by: Igor Mammedov <niallain@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Al Viro
Alexey Dobriyan
Linus Torvalds
Sukadev Bhattiprolu
Steve French
Jeff Layton
Jeff Layton
Igor Mammedov