GLOCK_BUG_ON() might call this function without RCU read lock. Make sure that
RCU read lock is held when using task_struct returned from pid_task().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
We need to wait for any outstanding DIO to complete in a couple
of situations. Firstly, in case we are changing out of deferred
mode (in inode_go_sync) where GLF_DIRTY will not be set. That
call could be prefixed with a test for gl_state == LM_ST_DEFERRED
but it doesn't seem worth it bearing in mind that the test for
outstanding DIO is very quick anyway, in the usual case that there
is none.
The second case is in inode_go_lock which will catch the cases
where we have a cached EX lock, but where we grant deferred locks
against it so that there is no glock state transistion. We only
need to wait if the state is not deferred, since DIO is valid
anyway in that state.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
In patch 209806aba9 we allowed
local deferred locks to be granted against a cached exclusive
lock. That opened up a corner case which this patch now
fixes.
The solution to the problem is to check whether we have cached
pages each time we do direct I/O and if so to unmap, flush
and invalidate those pages. Since the glock state machine
normally does that for us, mostly the code will be a no-op.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch fixes a slab memory leak that sometimes can occur
for files with a very short lifespan. The problem occurs when
a dinode is deleted before it has gotten to the journal properly.
In the leak scenario, the bd object is pinned for journal
committment (queued to the metadata buffers queue: sd_log_le_buf)
but is subsequently unpinned and dequeued before it finds its way
to the ail or the revoke queue. In this rare circumstance, the bd
object needs to be freed from slab memory, or it is forgotten.
We have to be very careful how we do it, though, because
multiple processes can call gfs2_remove_from_journal. In order to
avoid double-frees, only the process that does the unpinning is
allowed to free the bd.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Function gfs2_remove_from_ail drops the reference on the bh via
brelse. This patch fixes a race condition whereby bh is deferenced
after the brelse when setting bd->bd_blkno = bh->b_blocknr;
Under certain rare circumstances, bh might be gone or reused,
and bd->bd_blkno is set to whatever that memory happens to be,
which is often 0. Later, in gfs2_trans_add_unrevoke, that bd fails
the test "bd->bd_blkno >= blkno" which causes it to never be freed.
The end result is that the bd is never freed from the bufdata cache,
which results in this error:
slab error in kmem_cache_destroy(): cache `gfs2_bufdata': Can't free all objects
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is a GFS2 version of Tejun's patch:
4f331f01b9
vfs: don't hold s_umount over close_bdev_exclusive() call
In this case its blkdev_put itself that is the issue and this
patch uses the same solution of dropping and retaking s_umount.
Reported-by: Tejun Heo <tj@kernel.org>
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
In the case that atomic_open calls finish_no_open() with
the dentry that was supplied to gfs2_atomic_open() an
extra reference count is required. This patch fixes that
issue preventing a bug trap triggering at umount time.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Commit [e66cf1610: GFS2: Use lockref for glocks] replaced call:
atomic_read(&gi->gl->gl_ref) == 0
with:
__lockref_is_dead(&gl->gl_lockref)
therefore changing how gl is accessed, from gi->gl to plan gl.
However, gl can be a NULL pointer, and so gi->gl needs to be
used instead (which is guaranteed not to be NULL because fo
the while loop checking that condition).
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Pull vfs updates from Al Viro:
"All kinds of stuff this time around; some more notable parts:
- RCU'd vfsmounts handling
- new primitives for coredump handling
- files_lock is gone
- Bruce's delegations handling series
- exportfs fixes
plus misc stuff all over the place"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits)
ecryptfs: ->f_op is never NULL
locks: break delegations on any attribute modification
locks: break delegations on link
locks: break delegations on rename
locks: helper functions for delegation breaking
locks: break delegations on unlink
namei: minor vfs_unlink cleanup
locks: implement delegations
locks: introduce new FL_DELEG lock flag
vfs: take i_mutex on renamed file
vfs: rename I_MUTEX_QUOTA now that it's not used for quotas
vfs: don't use PARENT/CHILD lock classes for non-directories
vfs: pull ext4's double-i_mutex-locking into common code
exportfs: fix quadratic behavior in filehandle lookup
exportfs: better variable name
exportfs: move most of reconnect_path to helper function
exportfs: eliminate unused "noprogress" counter
exportfs: stop retrying once we race with rename/remove
exportfs: clear DISCONNECTED on all parents sooner
exportfs: more detailed comment for path_reconnect
...
Pull gfs2 updates from Steven Whitehouse:
"The main feature of interest this time is quota updates. There are
some clean ups and some patches to use the new generic lru list code.
There is still plenty of scope for some further changes in due course -
faster lookups of quota structures is very much on the todo list.
Also, a start has been made towards the more tricky issue of using the
generic lru code with glocks, but that will have to be completed in a
subsequent merge window.
The other, more minor feature, is that there have been a number of
performance patches which relate to block allocation. In particular
they will improve performance when the disk is nearly full"
* tag 'gfs2-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
GFS2: Use generic list_lru for quota
GFS2: Rename quota qd_lru_lock qd_lock
GFS2: Use reflink for quota data cache
GFS2: Use lockref for glocks
GFS2: Protect quota sync generation
GFS2: Inline qd_trylock into gfs2_quota_unlock
GFS2: Make two similar quota code fragments into a function
GFS2: Remove obsolete quota tunable
GFS2: Move gfs2_icbit_munge into quota.c
GFS2: Speed up starting point selection for block allocation
GFS2: Add allocation parameters structure
GFS2: Clean up reservation removal
GFS2: fix dentry leaks
GFS2: new function gfs2_rbm_incr
GFS2: Introduce rbm field bii
GFS2: Do not reset flags on active reservations
GFS2: introduce bi_blocks for optimization
GFS2: optimize rbm_from_block wrt bi_start
GFS2: d_splice_alias() can't return error
By using the generic list_lru code, we can now separate the
per sb quota list locking from the lru locking. The lru
lock is made into the inner-most lock.
As a result of this new lock order, we may occasionally see
items on the per-sb quota list which are "dead" so that the
two places where we traverse that list are updated to take
account of that.
As a result of this patch, the gfs2 quota shrinker is now
NUMA zone aware, and we are also laying the foundations for
further improvments in due course.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Abhijith Das <adas@redhat.com>
Tested-by: Abhijith Das <adas@redhat.com>
Cc: Dave Chinner <dchinner@redhat.com>
This is a straight forward rename which is in preparation for
introducing the generic list_lru infrastructure in the
following patch.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Abhijith Das <adas@redhat.com>
Tested-by: Abhijith Das <adas@redhat.com>
This patch adds reflink support to the quota data cache. It
looks a bit strange because we still don't have a sensible
split in the lookup by id and the lru list. That is coming in
later patches though.
The intent here is just to swap the current ref count for
reflinks in all cases with as little as possible other change.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Abhijith Das <adas@redhat.com>
Tested-by: Abhijith Das <adas@redhat.com>
Currently glocks have an atomic reference count and also a spinlock
which covers various internal fields, such as the state. This intent of
this patch is to replace the spinlock and the atomic reference count
with a lockref structure. This contains a spinlock which we can continue
to use as before, and a reference counter which is used in conjuction
with the spinlock to replace the previous atomic counter.
As a result of this there are some new rules for reference counting on
glocks. We need to distinguish between reference count changes under
gl_spin (which are now just increment or decrement of the new counter,
provided the count cannot hit zero) and those which are outside of
gl_spin, but which now take gl_spin internally.
The conversion is relatively straight forward. There is probably some
further clean up which can be done, but the priority at this stage is to
make the change in as simple a manner as possible.
A consequence of this change is that the reference count is being
decoupled from the lru list processing. This should allow future
adoption of the lru_list code with glocks in due course.
The reason for using the "dead" state and not just relying on 0 being
the "invalid state" is so that in due course 0 ref counts can be
allowable. The intent is to eventually be able to remove the ref count
changes which are currently hidden away in state_change().
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Now that gfs2_quota_sync can be potentially called from multiple
threads, we should protect this bit of code, and the sync generation
number in particular in order to ensure that there are no races
when syncing quotas.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>
The function qd_trylock was not a trylock despite its name and
can be inlined into gfs2_quota_unlock in order to make the
code a bit clearer. There should be no functional change as a
result of this patch.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>
There should be no functional change bar the removal of a
test of the MS_READONLY flag which would never be reachable.
This merges the common code from qd_fish and qd_trylock into
a single function and calls it from both those places.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>
There is no need for a paramater which relates to the internals
of quota to be exposed to users. The only possible use would be
to turn it up so large that the memory allocation fails. So lets
remove it and set it to a sensible value which ensures that we
don't ask for multipage allocations.
Currently the size of struct gfs2_holder means that the caluclated
value is identical to the previous default value, so there should
be no functional change.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>
This function is only called twice, and both callers are
quota related, so lets move this function into quota.c and
make it static.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
When setting the starting point for block allocation, there were calls
to both gfs2_rbm_to_block() and gfs2_rbm_from_block() in the common case
of there being an active reservation. The gfs2_rbm_from_block() function
can be quite slow, and since the two conversions were effectively a
no-op, it makes sense to avoid them entirely in this case.
There is no functional change here, but the code should be a bit more
efficient after this patch.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch adds a structure to contain allocation parameters with
the intention of future expansion of this structure. The idea is
that we should be able to add more information about the allocation
in the future in order to allow the allocator to make a better job
of placing the requests on-disk.
There is no functional difference from applying this patch.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The reservation for an inode should be cleared when it is truncated so
that we can start again at a different offset for future allocations.
We could try and do better than that, by resetting the search based on
where the truncation started from, but this is only a first step.
In addition, there are three callers of gfs2_rs_delete() but only one
of those should really be testing the value of i_writecount. While
we get away with that in the other cases currently, I think it would
be better if we made that test specific to the one case which
requires it.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
We need to dput() the result of d_splice_alias(), unless it is passed to
finish_no_open().
Edited by Steven Whitehouse in order to make it apply to the current
GFS2 git tree, and taking account of a prerequisite patch which hasn't
been applied.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: stable@vger.kernel.org
Tetsuo Handa
Steven Whitehouse
Bob Peterson
Michal Nazarewicz
Al Viro
Linus Torvalds
Miklos Szeredi