This flag currently only affects whether we allow "zero-copy" writes
with signing enabled. Typically we map pages in the pagecache directly
into the write request. If signing is enabled however and the contents
of the page change after the signature is calculated but before the
write is sent then the signature will be wrong. Servers typically
respond to this by closing down the socket.
Still, this can provide a performance benefit so the "Experimental" flag
was overloaded to allow this. That's really not a good place for this
option however since it's not clear what that flag does.
Move that flag instead to a new module parameter that better describes
its purpose. That's also better since it can be set at module insertion
time by configuring modprobe.d.
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Use for switching on strict cache mode. In this mode the
client reads from the cache all the time it has Oplock Level II,
otherwise - read from the server. As for write - the client stores
a data in the cache in Exclusive Oplock case, otherwise - write
directly to the server.
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Currently, the attribute cache timeout for CIFS is hardcoded to 1 second. This
means that the client might have to issue a QPATHINFO/QFILEINFO call every 1
second to verify if something has changes, which seems too expensive. On the
other hand, if the timeout is hardcoded to a higher value, workloads that
expect strict cache coherency might see unexpected results.
Making attribute cache timeout as a tunable will allow us to make a tradeoff
between performance and cache metadata correctness depending on the
application/workload needs.
Add 'actimeo' tunable that can be used to tune the attribute cache timeout.
The default timeout is set to 1 second. Also, display actimeo option value in
/proc/mounts.
It appears to me that 'actimeo' and the proposed (but not yet merged)
'strictcache' option cannot coexist, so care must be taken that we reset the
other option if one of them is set.
Changes since last post:
- fix option parsing and handle possible values correcly
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Update the README file to reflect that now DebugData shows all
the features enabled.
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Cc: Jeff Layton <jlayton@redhat.com>
--
fs/cifs/README | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
Signed-off-by: Steve French <sfrench@us.ibm.com>
On mount, "sec=ntlmssp" can now be specified to allow
"rawntlmssp" security to be enabled during
CIFS session establishment/authentication (ntlmssp used to
require specifying krb5 which was counterintuitive).
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>
Some applications/subsystems require mandatory byte range locks
(as is used for Windows/DOS/OS2 etc). Sending advisory (posix style)
byte range lock requests (instead of mandatory byte range locks) can
lead to problems for these applications (which expect that other
clients be prevented from writing to portions of the file which
they have locked and are updating). This mount option allows
mounting cifs with the new mount option "forcemand" (or
"forcemandatorylock") in order to have the cifs client use mandatory
byte range locks (ie SMB/CIFS/Windows/NTFS style locks) rather than
posix byte range lock requests, even if the server would support
posix byte range lock requests. This has no effect if the server
does not support the CIFS Unix Extensions (since posix style locks
require support for the CIFS Unix Extensions), but for mounts
to Samba servers this can be helpful for Wine and applications
that require mandatory byte range locks.
Acked-by: Jeff Layton <jlayton@redhat.com>
CC: Alexander Bokovoy <ab@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
fcntl(F_SETLEASE) currently is not exported by cifs (nor by local file
systems) so cifs grants leases based on how other local processes have
opened the file not by whether the file is cacheable (oplocked). This
adds the check to make sure that the file is cacheable on the client
before checking whether we can grant the lease locally
(generic_setlease). It also adds a mount option for cifs (locallease)
if the user wants to override this and try to grant leases even
if the server did not grant oplock.
Signed-off-by: Steve French <sfrench@us.ibm.com>
Older samba server (eg. 3.0.24 from Debian etch) don't work correctly,
if DFS paths are used. Such server claim that they support DFS, but fail
to process some requests with DFS paths. Starting with Linux 2.6.26,
the cifs clients starts sending DFS paths in such situations, rendering
it unuseable with older samba servers.
The nodfs mount options forces a share to be used with non DFS paths,
even if the server claims, that it supports it.
Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Igor Mammedov <niallain@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Samba now supports transport encryption on particular exports
(mounted tree ids can be encrypted for servers which support the
unix extensions). This adds parsing support to cifs mount
option parsing for this.
Signed-off-by: Steve French <sfrench@us.ibm.com>
Fix RedHat bug 329431
The idea here is separate "conscious" from "unconscious" flushes.
Conscious flushes are those due to a fsync() or close(). Unconscious
ones are flushes that occur as a side effect of some other operation or
due to memory pressure.
Currently, when an error occurs during an unconscious flush (ENOSPC or
EIO), we toss out the page and don't preserve that error to report to
the user when a conscious flush occurs. If after the unconscious flush,
there are no more dirty pages for the inode, the conscious flush will
simply return success even though there were previous errors when writing
out pages. This can lead to data corruption.
The easiest way to reproduce this is to mount up a CIFS share that's
very close to being full or where the user is very close to quota. mv
a file to the share that's slightly larger than the quota allows. The
writes will all succeed (since they go to pagecache). The mv will do a
setattr to set the new file's attributes. This calls
filemap_write_and_wait,
which will return an error since all of the pages can't be written out.
Then later, when the flush and release ops occur, there are no more
dirty pages in pagecache for the file and those operations return 0. mv
then assumes that the file was written out correctly and deletes the
original.
CIFS already has a write_behind_rc variable where it stores the results
from earlier flushes, but that value is only reported in cifs_close.
Since the VFS ignores the return value from the release operation, this
isn't helpful. We should be reporting this error during the flush
operation.
This patch does the following:
1) changes cifs_fsync to use filemap_write_and_wait and cifs_flush and also
sync to check its return code. If it returns successful, they then check
the value of write_behind_rc to see if an earlier flush had reported any
errors. If so, they return that error and clear write_behind_rc.
2) sets write_behind_rc in a few other places where pages are written
out as a side effect of other operations and the code waits on them.
3) changes cifs_setattr to only call filemap_write_and_wait for
ATTR_SIZE changes.
4) makes cifs_writepages accurately distinguish between EIO and ENOSPC
errors when writing out pages.
Some simple testing indicates that the patch works as expected and that
it fixes the reproduceable known problem.
Acked-by: Dave Kleikamp <shaggy@austin.rr.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Caused by unneeded reopen during reconnect while spinlock held.
Fixes kernel bugzilla bug #7903
Thanks to Lin Feng Shen for testing this, and Amit Arora for
some nice problem determination to narrow this down.
Acked-by: Dave Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
nfsd is passing null nameidata (probably the only one doing that)
on call to create - cifs was missing one check for this.
Note that running nfsd over a cifs mount requires specifying fsid on
the nfs exports entry and requires mounting cifs with serverino mount
option.
Signed-off-by: Steve French <sfrench@us.ibm.com>
We had a customer report that attempting to make CIFS mount with a null
username (i.e. doing an anonymous mount) doesn't work. Looking through the
code, it looks like CIFS expects a NULL username from userspace in order
to trigger an anonymous mount. The mount.cifs code doesn't seem to ever
pass a null username to the kernel, however.
It looks also like the kernel can take a sec=none option, but it only seems
to look at it if the username is already NULL. This seems redundant and
effectively makes sec=none useless.
The following patch makes sec=none force an anonymous mount.
Signed-off-by: Steve French <sfrench@us.ibm.com>
When CIFS Unix Extensions are negotiated we get the Unix uid and gid
owners of the file from the server (on the Unix Query Path Info
levels), but if the server's uids don't match the client uid's users
were having to disable the Unix Extensions (which turned off features
they still wanted). The changeset patch allows users to override uid
and/or gid for file/directory owner with a default uid and/or gid
specified at mount (as is often done when mounting from Linux cifs
client to Windows server). This changeset also displays the uid
and gid used by default in /proc/mounts (if applicable).
Also cleans up code by adding some of the missing spaces after
"if" keywords per-kernel style guidelines (as suggested by Randy Dunlap
when he reviewed the patch).
Signed-off-by: Steve French <sfrench@us.ibm.com>
in directory
Also includes first part of fix to compensate for servers which forget
to return . and .. as well as updates to changelog and cifs readme.
Signed-off-by: Steve French <sfrench@us.ibm.com>
disabled. Also set mode, uid, gid better on mkdir and create for the
case when Unix Extensions is not enabled and setuids is enabled. This is
necessary to fix the hole in which chown could be allowed for non-root
users in some cases if root mounted, and also to display the mode and uid
properly in some cases.
Signed-off-by: Steve French <sfrench@us.ibm.com>
New cifs_writepages routine was not updated bytes written in cifs stats.
Also added ability to clear /proc/fs/cifs/Stats by writing (0 or 1) to it.
Signed-off-by: Steve French <sfrench@us.ibm.com>
over the wire (to help the case when applications break with cifs mandatory
lock behavior. Add part one of mount option for requesting case
insensitive path name matching.
Signed-off-by: Steve French (sfrench@us.ibm.com)
There's no longer a reason to document the obsolete BK usage.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
.. since it can be due to pending kill.
Update readme information to better describe cifs umount
Signed-off-by: Steve French (sfrench@us.ibm.com)
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
For handling seven special characters that shells use for filenames.
This first parts implements conversions from Unicode.
Signed-off-by: Steve French
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Jeff Layton