linux.git/include/linux/reiserfs_fs_sb.h, branch master

kill reiserfs_fs_{i,sb}.h

2012-03-21T01:29:43+00:00

Signed-off-by: Al Viro

reiserfs: Properly display mount options in /proc/mounts

2012-01-07T04:20:13+00:00

Make reiserfs properly display mount options in /proc/mounts.

CC: reiserfs-devel@vger.kernel.org
Signed-off-by: Jan Kara 
Signed-off-by: Al Viro

kill-the-bkl/reiserfs: move the concurrent tree accesses checks per superblock

2009-09-14T05:18:25+00:00

When do_balance() balances the tree, a trick is performed to
provide the ability for other tree writers/readers to check whether
do_balance() is executing concurrently (requires CONFIG_REISERFS_CHECK).

This is done to protect concurrent accesses to the tree. The trick
is the following:

When do_balance is called, a unique global variable called cur_tb
takes a pointer to the current tree to be rebalanced.
Once do_balance finishes its work, cur_tb takes the NULL value.

Then, concurrent tree readers/writers just have to check the value
of cur_tb to ensure do_balance isn't executing concurrently.
If it is, then it proves that schedule() occured on do_balance(),
which then relaxed the bkl that protected the tree.

Now that the bkl has be turned into a mutex, this check is still
fine even though do_balance() becomes preemptible: the write lock
will not be automatically released on schedule(), so the tree is
still protected.

But this is only fine if we have a single reiserfs mountpoint.
Indeed, because the bkl is a global lock, it didn't allowed
concurrent executions between a tree reader/writer in a mount point
and a do_balance() on another tree from another mountpoint.

So assuming all these readers/writers weren't supposed to be
reentrant, the current check now sometimes detect false positives with
the current per-superblock mutex which allows this reentrancy.

This patch keeps the concurrent tree accesses check but moves it
per superblock, so that only trees from a same mount point are
checked to be not accessed concurrently.

[ Impact: fix spurious panic while running several reiserfs mount-points ]

Cc: Jeff Mahoney 
Cc: Chris Mason 
Cc: Ingo Molnar 
Cc: Alexander Beregalov 
Signed-off-by: Frederic Weisbecker

reiserfs: kill-the-BKL

2009-09-14T05:17:59+00:00

This patch is an attempt to remove the Bkl based locking scheme from
reiserfs and is intended.

It is a bit inspired from an old attempt by Peter Zijlstra:

   http://lkml.indiana.edu/hypermail/linux/kernel/0704.2/2174.html

The bkl is heavily used in this filesystem to prevent from
concurrent write accesses on the filesystem.

Reiserfs makes a deep use of the specific properties of the Bkl:

- It can be acqquired recursively by a same task
- It is released on the schedule() calls and reacquired when schedule() returns

The two properties above are a roadmap for the reiserfs write locking so it's
very hard to simply replace it with a common mutex.

- We need a recursive-able locking unless we want to restructure several blocks
  of the code.
- We need to identify the sites where the bkl was implictly relaxed
  (schedule, wait, sync, etc...) so that we can in turn release and
  reacquire our new lock explicitly.
  Such implicit releases of the lock are often required to let other
  resources producer/consumer do their job or we can suffer unexpected
  starvations or deadlocks.

So the new lock that replaces the bkl here is a per superblock mutex with a
specific property: it can be acquired recursively by a same task, like the
bkl.

For such purpose, we integrate a lock owner and a lock depth field on the
superblock information structure.

The first axis on this patch is to turn reiserfs_write_(un)lock() function
into a wrapper to manage this mutex. Also some explicit calls to
lock_kernel() have been converted to reiserfs_write_lock() helpers.

The second axis is to find the important blocking sites (schedule...(),
wait_on_buffer(), sync_dirty_buffer(), etc...) and then apply an explicit
release of the write lock on these locations before blocking. Then we can
safely wait for those who can give us resources or those who need some.
Typically this is a fight between the current writer, the reiserfs workqueue
(aka the async commiter) and the pdflush threads.

The third axis is a consequence of the second. The write lock is usually
on top of a lock dependency chain which can include the journal lock, the
flush lock or the commit lock. So it's dangerous to release and trying to
reacquire the write lock while we still hold other locks.

This is fine with the bkl:

      T1                       T2

lock_kernel()
    mutex_lock(A)
    unlock_kernel()
    // do something
                            lock_kernel()
                                mutex_lock(A) -> already locked by T1
                                schedule() (and then unlock_kernel())
    lock_kernel()
    mutex_unlock(A)
    ....

This is not fine with a mutex:

      T1                       T2

mutex_lock(write)
    mutex_lock(A)
    mutex_unlock(write)
    // do something
                           mutex_lock(write)
                              mutex_lock(A) -> already locked by T1
                              schedule()

    mutex_lock(write) -> already locked by T2
    deadlock

The solution in this patch is to provide a helper which releases the write
lock and sleep a bit if we can't lock a mutex that depend on it. It's another
simulation of the bkl behaviour.

The last axis is to locate the fs callbacks that are called with the bkl held,
according to Documentation/filesystem/Locking.

Those are:

- reiserfs_remount
- reiserfs_fill_super
- reiserfs_put_super

Reiserfs didn't need to explicitly lock because of the context of these callbacks.
But now we must take care of that with the new locking.

After this patch, reiserfs suffers from a slight performance regression (for now).
On UP, a high volume write with dd reports an average of 27 MB/s instead
of 30 MB/s without the patch applied.

Signed-off-by: Frederic Weisbecker 
Reviewed-by: Ingo Molnar 
Cc: Jeff Mahoney 
Cc: Peter Zijlstra 
Cc: Bron Gondwana 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Alexander Viro 
LKML-Reference: <1239070789-13354-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar

reiserfs: allow exposing privroot w/ xattrs enabled

2009-06-12T01:35:58+00:00

This patch adds an -oexpose_privroot option to allow access to the privroot.

Signed-off-by: Jeff Mahoney 
Signed-off-by: Al Viro

reiserfs: remove privroot hiding in lookup

2009-05-09T14:49:39+00:00

 With Al Viro's patch to move privroot lookup to fs mount, there's no need
 to have special code to hide the privroot in reiserfs_lookup.

 I've also cleaned up the privroot hiding in reiserfs_readdir_dentry and
 removed the last user of reiserfs_xattrs().

Signed-off-by: Jeff Mahoney 
Signed-off-by: Al Viro

reiserfs: fixup xattr_root caching

2009-05-09T14:49:39+00:00

 The xattr_root caching was broken from my previous patch set. It wouldn't
 cause corruption, but could cause decreased performance due to allocating
 a larger chunk of the journal (~ 27 blocks) than it would actually use.

 This patch loads the xattr root dentry at xattr initialization and creates
 it on-demand. Since we're using the cached dentry, there's no point
 in keeping lookup_or_create_dir around, so that's removed.

Signed-off-by: Jeff Mahoney 
Signed-off-by: Al Viro

reiserfs: fix j_last_flush_trans_id type

2009-04-21T03:29:41+00:00

Conversion in commit 600ed41675d8c384519d8f0b3c76afed39ef2f4b had missed
that one, but converted format from %lu to %u.  As the result,
/proc/..../journal got buggered on 64bit boxen.

Signed-off-by: Al Viro

reiserfs: strip trailing whitespace

2009-03-30T19:16:39+00:00

This patch strips trailing whitespace from the reiserfs code.

Signed-off-by: Jeff Mahoney 
Signed-off-by: Linus Torvalds

reiserfs: use generic xattr handlers

2009-03-30T19:16:38+00:00

Christoph Hellwig had asked me quite some time ago to port the reiserfs
xattrs to the generic xattr interface.

This patch replaces the reiserfs-specific xattr handling code with the
generic struct xattr_handler.

However, since reiserfs doesn't split the prefix and name when accessing
xattrs, it can't leverage generic_{set,get,list,remove}xattr without
needlessly reconstructing the name on the back end.

Update 7/26/07: Added missing dput() to deletion path.
Update 8/30/07: Added missing mark_inode_dirty when i_mode is used to
                represent an ACL and no previous ACL existed.

Signed-off-by: Jeff Mahoney 
Signed-off-by: Linus Torvalds