Commit Graph

234 Commits

Author SHA1 Message Date
Steve French
96daf2b091 [CIFS] Rename three structures to avoid camel case
secMode to sec_mode
and
cifsTconInfo to cifs_tcon
and
cifsSesInfo to cifs_ses

Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-27 04:34:02 +00:00
Pavel Shilovsky
d4ffff1fa9 CIFS: Add rwpidforward mount option
Add rwpidforward mount option that switches on a mode when we forward
pid of a process who opened a file to any read and write operation.

This can prevent applications like WINE from failing on read or write
operation on a previously locked file region from the same netfd from
another process if we use mandatory brlock style.

It is actual for WINE because during a run of WINE program two processes
work on the same netfd - share the same file struct between several VFS
fds:
1) WINE-server does open and lock;
2) WINE-application does read and write.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-27 03:57:16 +00:00
Pavel Shilovsky
25c7f41e92 CIFS: Migrate to shared superblock model
Add cifs_match_super to use in sget to share superblock between mounts
that have the same //server/sharename, credentials and mount options.
It helps us to improve performance on work with future SMB2.1 leases.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-27 03:53:23 +00:00
Steve French
f87d39d951 [CIFS] Migrate from prefixpath logic
Now we point superblock to a server share root and set a root dentry
appropriately. This let us share superblock between mounts like
//server/sharename/foo/bar and //server/sharename/foo further.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>

Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-27 03:50:55 +00:00
Pavel Shilovsky
641a58d66d CIFS: Fix memory leak in cifs_do_mount
and simplify error handling code.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-27 03:45:37 +00:00
Pavel Shilovsky
b2e5cd33b5 CIFS: Fix undefined behavior when mount fails
Fix double kfree() calls on the same pointers and cleanup mount code.

Reviewed-and-Tested-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-25 20:02:31 +00:00
Pavel Shilovsky
724d9f1cfb CIFS: Simplify mount code for further shared sb capability
Reorganize code to get mount option at first and when get a superblock.
This lets us use shared superblock model further for equal mounts.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-24 03:07:42 +00:00
Steve French
156ecb2d8b [CIFS] Fix to problem with getattr caused by invalidate simplification patch
Fix to earlier "Simplify invalidate part (try #6)" patch
That patch caused problems with connectathon test 5.

Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-20 17:00:01 +00:00
Shirish Pargaonkar
c4aca0c09f cifs: Change key name to cifs.idmap, misc. clean-up
Change idmap key name from cifs.cifs_idmap to cifs.idmap.
Removed unused structure wksidarr and function match_sid().
Handle errors correctly in function init_cifs().

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:56 +00:00
Sean Finney
f14bcf71d1 cifs: Unconditionally copy mount options to superblock info
Previously mount options were copied and updated in the cifs_sb_info
struct only when CONFIG_CIFS_DFS_UPCALL was enabled.  Making this
information generally available allows us to remove a number of ifdefs,
extra function params, and temporary variables.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Sean Finney <seanius@seanius.net>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:55 +00:00
Sean Finney
5167f11ec9 cifs: Use kstrndup for cifs_sb->mountdata
A relatively minor nit, but also clarified the "consensus" from the
preceding comments that it is in fact better to try for the kstrdup
early and cleanup while cleaning up is still a simple thing to do.

Reviewed-By: Steve French <smfrench@gmail.com>
Signed-off-by: Sean Finney <seanius@seanius.net>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:55 +00:00
Pavel Shilovsky
6feb9891da CIFS: Simplify invalidate part (try #5)
Simplify many places when we call cifs_revalidate/invalidate to make
it do what it exactly needs.

Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:52 +00:00
Pavel Shilovsky
0b81c1c405 CIFS: directio read/write cleanups
Recently introduced strictcache mode brought a new code that can be
efficiently used by directio part. That's let us add vectored operations
and break unnecessary cifs_user_read and cifs_user_write.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:51 +00:00
Shirish Pargaonkar
4d79dba0e0 cifs: Add idmap key and related data structures and functions (try #17 repost)
Define (global) data structures to store ids, uids and gids, to which a
SID maps.  There are two separate trees, one for SID/uid and another one
for SID/gid.

A new type of key, cifs_idmap_key_type, is used.

Keys are instantiated and searched using credential of the root by
overriding and restoring the credentials of the caller requesting the key.

Id mapping functions are invoked under config option of cifs acl.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:51 +00:00
Shirish Pargaonkar
257208736a cifs: cleanup: Rename and remove config flags
Remove config flag CIFS_EXPERIMENTAL.
Do export operations under new config flag CIFS_NFSD_EXPORT

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:49 +00:00
Steve French
0eff0e2677 Remove unused CIFSSMBNotify worker function
The CIFSSMBNotify worker is unused, pending changes to allow it to be called
via inotify, so move it into its own experimental config option so it does
not get built in, until the necessary VFS support is fixed.  It used to
be used in dnotify, but according to Jeff, inotify needs minor changes
before we can reenable this.

CC: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:47 +00:00
Shirish Pargaonkar
9b6763e0aa cifs: Remove unused inode number while fetching root inode
ino is unused in function cifs_root_iget().

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-05-19 14:10:47 +00:00
Jeff Layton
ca83ce3d5b cifs: don't allow mmap'ed pages to be dirtied while under writeback (try #3)
This is more or less the same patch as before, but with some merge
conflicts fixed up.

If a process has a dirty page mapped into its page tables, then it has
the ability to change it while the client is trying to write the data
out to the server. If that happens after the signature has been
calculated then that signature will then be wrong, and the server will
likely reset the TCP connection.

This patch adds a page_mkwrite handler for CIFS that simply takes the
page lock. Because the page lock is held over the life of writepage and
writepages, this prevents the page from becoming writeable until
the write call has completed.

With this, we can also remove the "sign_zero_copy" module option and
always inline the pages when writing.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-04-12 14:19:55 +00:00
Jeff Layton
2b6c26a0a6 cifs: set ra_pages in backing_dev_info
Commit 522440ed made cifs set backing_dev_info on the mapping attached
to new inodes. This change caused a fairly significant read performance
regression, as cifs started doing page-sized reads exclusively.

By virtue of the fact that they're allocated as part of cifs_sb_info by
kzalloc, the ra_pages on cifs BDIs get set to 0, which prevents any
readahead. This forces the normal read codepaths to use readpage instead
of readpages causing a four-fold increase in the number of read calls
with the default rsize.

Fix it by setting ra_pages in the BDI to the same value as that in the
default_backing_dev_info.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=31662

Cc: stable@kernel.org
Reported-and-Tested-by: Till <till2.schaefer@uni-dortmund.de>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-04-12 00:56:00 +00:00
Steve French
8727c8a85f Allow user names longer than 32 bytes
We artificially limited the user name to 32 bytes, but modern servers handle
larger.  Set the maximum length to a reasonable 256, and make the user name
string dynamically allocated rather than a fixed size in session structure.
Also clean up old checkpatch warning.

Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-04-12 00:42:06 +00:00
Jeff Layton
bdf1b03e09 cifs: replace /proc/fs/cifs/Experimental with a module parm
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>
2011-04-12 00:40:43 +00:00
Pavel Shilovsky
72432ffcf5 CIFS: Implement cifs_strict_writev (try #4)
If we don't have Exclusive oplock we write a data to the server.
Also set invalidate_mapping flag on the inode if we wrote something
to the server. Add cifs_iovec_write to let the client write iovec
buffers through CIFSSMBWrite2.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-01-25 19:30:13 +00:00
Pavel Shilovsky
a70307eeeb CIFS: Implement cifs_strict_readv (try #4)
Read from the cache if we have at least Level II oplock - otherwise
read from the server. Add cifs_user_readv to let the client read into
iovec buffers.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-01-20 21:42:29 +00:00
Pavel Shilovsky
7a6a19b17a CIFS: Implement cifs_file_strict_mmap (try #2)
Invalidate inode mapping if we don't have at least Level II oplock.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-01-20 21:42:25 +00:00
Pavel Shilovsky
8be7e6ba14 CIFS: Implement cifs_strict_fsync
Invalidate inode mapping if we don't have at least Level II oplock in
cifs_strict_fsync. Also remove filemap_write_and_wait call from cifs_fsync
because it is previously called from vfs_fsync_range. Add file operations'
structures for strict cache mode.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-01-20 21:42:21 +00:00
Steve French
fda3594362 [CIFS] cifs: reconnect unresponsive servers
If the server isn't responding to echoes, we don't want to leave tasks
hung waiting for it to reply. At that point, we'll want to reconnect
so that soft mounts can return an error to userspace quickly.

If the client hasn't received a reply after a specified number of echo
intervals, assume that the transport is down and attempt to reconnect
the socket.

The number of echo_intervals to wait before attempting to reconnect is
tunable via a module parameter. Setting it to 0, means that the client
will never attempt to reconnect. The default is 5.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
2011-01-20 18:06:34 +00:00
Al Viro
1c929cfe6d switch cifs
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-12 20:02:46 -05:00
Jeff Layton
20054bd657 cifs: use CreationTime like an i_generation field
Reduce false inode collisions by using the CreationTime like an
i_generation field. This way, even if the server ends up reusing
a uniqueid after a delete/create cycle, we can avoid matching
the inode incorrectly.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-01-09 23:43:00 +00:00
Steve French
acc6f11272 Merge branch 'master' of /pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
	fs/cifs/dir.c
2011-01-09 23:18:16 +00:00
Nick Piggin
b74c79e993 fs: provide rcu-walk aware permission i_ops
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:29 +11:00
Nick Piggin
fa0d7e3de6 fs: icache RCU free inodes
RCU free the struct inode. This will allow:

- Subsequent store-free path walking patch. The inode must be consulted for
  permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
  to take i_lock no longer need to take sb_inode_list_lock to walk the list in
  the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
  page lock to follow page->mapping.

The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.

In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.

The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:26 +11:00
Pavel Shilovsky
a9f1b85e5b CIFS: Simplify ipv*_connect functions into one (try #4)
Make connect logic more ip-protocol independent and move RFC1001 stuff into
a separate function. Also replace union addr in TCP_Server_Info structure
with sockaddr_storage.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-and-Tested-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-01-06 19:07:53 +00:00
Jeff Layton
8846399968 cifs: remove Local_System_Name
...this string is zeroed out and nothing ever changes it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-12-06 22:45:19 +00:00
Suresh Jayaraman
6d20e8406f cifs: add attribute cache timeout (actimeo) tunable
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>
2010-12-02 19:32:11 +00:00
Suresh Jayaraman
476428f8c3 cifs: display fsc in /proc/mounts
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-11-30 05:51:49 +00:00
Pavel Shilovsky
c67236281c cifs: make cifs_set_oplock_level() take a cifsInodeInfo pointer
All the callers already have a pointer to struct cifsInodeInfo. Use it.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-11-05 17:39:01 +00:00
Jeff Layton
b647c35f77 cifs: convert tlink_tree to a rbtree
Radix trees are ideal when you want to track a bunch of pointers and
can't embed a tracking structure within the target of those pointers.
The tradeoff is an increase in memory, particularly if the tree is
sparse.

In CIFS, we use the tlink_tree to track tcon_link structs. A tcon_link
can never be in more than one tlink_tree, so there's no impediment to
using a rb_tree here instead of a radix tree.

Convert the new multiuser mount code to use a rb_tree instead. This
should reduce the memory required to manage the tlink_tree.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-11-02 19:20:23 +00:00
Christoph Hellwig
51ee4b84f5 locks: let the caller free file_lock on ->setlease failure
The caller allocated it, the caller should free it.

The only issue so far is that we could change the flp pointer even on an
error return if the fl_change callback failed.  But we can simply move
the flp assignment after the fl_change invocation, as the callers don't
care about the flp return value if the setlease call failed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-31 06:35:15 -07:00
J. Bruce Fields
05fa3135fd locks: fix setlease methods to free passed-in lock
We modified setlease to require the caller to allocate the new lease in
the case of creating a new lease, but forgot to fix up the filesystem
methods.

Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-30 18:08:15 -07:00
Linus Torvalds
b4020c1b19 Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  cifs: Cleanup and thus reduce smb session structure and fields used during authentication
  NTLM auth and sign - Use appropriate server challenge
  cifs: add kfree() on error path
  NTLM auth and sign - minor error corrections and cleanup
  NTLM auth and sign - Use kernel crypto apis to calculate hashes and smb signatures
  NTLM auth and sign - Define crypto hash functions and create and send keys needed for key exchange
  cifs: cifs_convert_address() returns zero on error
  NTLM auth and sign - Allocate session key/client response dynamically
  cifs: update comments - [s/GlobalSMBSesLock/cifs_file_list_lock/g]
  cifs: eliminate cifsInodeInfo->write_behind_rc (try #6)
  [CIFS] Fix checkpatch warnings and bump cifs version number
  cifs: wait for writeback to complete in cifs_flush
  cifs: convert cifsFileInfo->count to non-atomic counter
2010-10-29 10:37:27 -07:00
Al Viro
d753ed9759 convert cifs
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29 04:16:56 -04:00
Jeff Layton
eb4b756b1e cifs: eliminate cifsInodeInfo->write_behind_rc (try #6)
write_behind_rc is redundant and just adds complexity to the code. What
we really want to do instead is to use mapping_set_error to reset the
flags on the mapping when we find a writeback error and can't report it
to userspace yet.

For cifs_flush and cifs_fsync, we shouldn't reset the flags since errors
returned there do get reported to userspace.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Reviewed-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-10-25 00:19:00 +00:00
Linus Torvalds
d2ecad9fac Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6: (56 commits)
  [CIFS] move close processing  from cifs_close to cifsFileInfo_put
  cifs: convert cifs_tcp_ses_lock from a rwlock to a spinlock
  cifs: cancel_delayed_work() + flush_scheduled_work() -> cancel_delayed_work_sync()
  Clean up two declarations of blob_len
  cifs: move cifsFileInfo_put to file.c
  cifs: convert GlobalSMBSeslock from a rwlock to regular spinlock
  [CIFS] Fix minor checkpatch warning and update cifs version
  cifs: move cifs_new_fileinfo to file.c
  cifs: eliminate pfile pointer from cifsFileInfo
  cifs: cifs_write argument change and cleanup
  cifs: clean up cifs_reopen_file
  cifs: eliminate the inode argument from cifs_new_fileinfo
  cifs: eliminate oflags option from cifs_new_fileinfo
  cifs: fix flags handling in cifs_posix_open
  cifs: eliminate cifs_posix_open_inode_helper
  cifs: handle FindFirst failure gracefully
  NTLM authentication and signing - Calculate auth response per smb session
  cifs: don't use vfsmount to pin superblock for oplock breaks
  cifs: keep dentry reference in cifsFileInfo instead of inode reference
  cifs: on multiuser mount, set ownership to current_fsuid/current_fsgid (try #7)
  ...

Fix up trivial conflict in fs/cifs/cifsfs.c due to added/removed header files
2010-10-22 17:52:29 -07:00
Suresh Jayaraman
3f9bcca782 cifs: convert cifs_tcp_ses_lock from a rwlock to a spinlock
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>
2010-10-21 13:14:27 +00:00
Jeff Layton
4477288a10 cifs: convert GlobalSMBSeslock from a rwlock to regular spinlock
Convert this lock to a regular spinlock

A rwlock_t offers little value here. It's more expensive than a regular
spinlock unless you have a fairly large section of code that runs under
the read lock and can benefit from the concurrency.

Additionally, we need to ensure that the refcounting for files isn't
racy and to do that we need to lock areas that can increment it for
write. That means that the areas that can actually use a read_lock are
very few and relatively infrequently used.

While we're at it, change the name to something easier to type, and fix
a bug in find_writable_file. cifsFileInfo_put can sleep and shouldn't be
called while holding the lock.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-10-18 01:32:01 +00:00
Jeff Layton
d7c86ff8cd cifs: don't use vfsmount to pin superblock for oplock breaks
Filesystems aren't really supposed to do anything with a vfsmount. It's
considered a layering violation since vfsmounts are entirely managed at
the VFS layer.

CIFS currently keeps an active reference to a vfsmount in order to
prevent the superblock vanishing before an oplock break has completed.
What we really want to do instead is to keep sb->s_active high until the
oplock break has completed. This patch borrows the scheme that NFS uses
for handling sillyrenames.

An atomic_t is added to the cifs_sb_info. When it transitions from 0 to
1, an extra reference to the superblock is taken (by bumping the
s_active value). When it transitions from 1 to 0, that reference is
dropped and a the superblock teardown may proceed if there are no more
references to it.

Also, the vfsmount pointer is removed from cifsFileInfo and from
cifs_new_fileinfo, and some bogus forward declarations are removed from
cifsfs.h.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-10-12 18:08:01 +00:00
Jeff Layton
0dd12c2195 cifs: initialize tlink_tree_lock and tlink_tree
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-10-08 16:34:49 +00:00
Jeff Layton
29e07c82a9 cifs: fix cifs_show_options to show "username=" or "multiuser"
...based on CIFS_MOUNT_MULTIUSER flag.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-10-06 16:13:11 +00:00
Jeff Layton
13cfb7334e cifs: have cifsFileInfo hold a reference to a tlink rather than tcon pointer
cifsFileInfo needs a pointer to a tcon, but it doesn't currently hold a
reference to it. Change it to keep a pointer to a tcon_link instead and
hold a reference to it.

That will keep the tcon from being freed until the file is closed.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-10-06 16:12:49 +00:00
Arnd Bergmann
b89f432133 fs/locks.c: prepare for BKL removal
This prepares the removal of the big kernel lock from the
file locking code. We still use the BKL as long as fs/lockd
uses it and ceph might sleep, but we can flip the definition
to a private spinlock as soon as that's done.
All users outside of fs/lockd get converted to use
lock_flocks() instead of lock_kernel() where appropriate.

Based on an earlier patch to use a spinlock from Matthew
Wilcox, who has attempted this a few times before, the
earliest patch from over 10 years ago turned it into
a semaphore, which ended up being slower than the BKL
and was subsequently reverted.

Someone should do some serious performance testing when
this becomes a spinlock, since this has caused problems
before. Using a spinlock should be at least as good
as the BKL in theory, but who knows...

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Sage Weil <sage@newdream.net>
Cc: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
2010-10-05 11:02:04 +02:00