Well I don't get the same warning locally as the kbuild
robot, but I guess this should fix the problem, anyway.
Here is the warning:

head:   2d9e7230
commit: ee2411a8 [19/20] GFS2: Clean up quota slot allocation
config: make ARCH=powerpc allmodconfig

All error/warnings:

   fs/gfs2/quota.c: In function 'gfs2_quota_init':
>> fs/gfs2/quota.c:1246:3: error: implicit declaration of function '__vmalloc' [-Werror=implicit-function-declaration]
      sdp->sd_quota_bitmap = __vmalloc(bm_size, GFP_NOFS, PAGE_KERNEL);
      ^
>> fs/gfs2/quota.c:1246:24: warning: assignment makes pointer from integer without a cast [enabled by default]
      sdp->sd_quota_bitmap = __vmalloc(bm_size, GFP_NOFS, PAGE_KERNEL);
                           ^
   fs/gfs2/quota.c: In function 'gfs2_quota_cleanup':
>> fs/gfs2/quota.c:1361:4: error: implicit declaration of function 'vfree' [-Werror=implicit-function-declaration]
       vfree(sdp->sd_quota_bitmap);
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Gradually, the global qd_lock is being used for less and less.
After this patch it will only be used for the per super block
list whose purpose is to allow syncing of changes back to the
master quota file from the local quota changes file. Fixing
up that process to make it more efficient will be the subject
of a later patch, however this patch removes another barrier
to doing that.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>

Quota slot allocation has historically used a vector of pages
and a set of homegrown find/test/set/clear bit functions. Since
the size of the bitmap is likely to be based on the default
qc file size, thats a couple of pages at most. So we ought
to be able to allocate that as a single chunk, with a vmalloc
fallback, just in case of memory fragmentation.

We are then able to use the kernel's own find/test/set/clear
bit functions, rather than rolling our own.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>

While investigating a rather strange bit of code in the quota
clean up function, I spotted that the reason for its existence
was that when remounting read only, we were not stopping the
quotad thread, and thus it was possible for it to still have
a reference to some of the quotas in that case.

This patch moves the logd and quota thread start and stop into
the make_fs_rw/ro functions, so that we now stop those threads
when mounted read only.

This means that quotad will always be stopped before we call
the quota clean up function, and we can thus dispose of the
(rather hackish) code that waits for it to give up its
reference on the quotas.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>

Prior to this patch, GFS2 kept all the quotas for each
super block in a single linked list. This is rather slow
when there are large numbers of quotas.

This patch introduces a hlist_bl based hash table, similar
to the one used for glocks. The initial look up of the quota
is now lockless in the case where it is already cached,
although we still have to take the per quota spinlock in
order to bump the ref count. Either way though, this is a
big improvement on what was there before.

The qd_lock and the per super block list is preserved, for
the time being. However it is intended that since this is no
longer used for its original role, it should be possible to
shrink the number of items on that list in due course and
remove the requirement to take qd_lock in qd_get.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

We recently fixed the writeback of pages prior to performing
direct i/o, however the initial fix was perhaps a bit heavy
handed. There is no need to invalidate pages if the direct i/o
is only a read, since they will be identical to what has been
flushed to disk anyway.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Spotted by Andy Price. This should fix the odd messages from
lockdep caused by 70d4ee94Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Price <anprice@redhat.com>

This patch adds four new fields to directory leaf blocks.
The intent is not to use them in the kernel itself, although
perhaps we may be able to use them as hints at some later date,
but instead to provide more information for debug/fsck use.

One new field adds a pointer to the inode to which the leaf
belongs. This can be useful if the pointer to the leaf block
has become corrupt, as it will allow us to know which inode
this block should be associated with. This field is set when
the leaf is created and never changed over its lifetime.

The second field is a "distance from the hash table" field.
The meaning is as follows:
 0  = An old leaf in which this value has not been set
 1  = This leaf is pointed to directly from the hash table
 2+ = This leaf is part of a chain, pointed to by another leaf
      block, the value gives the position in the chain.

The third and fourth fields combine to give a time stamp of
the most recent directory insertion or deletion from this
leaf block. The time stamp is not updated when a new leaf
block is chained from the current one. The code is currently
written such that the timestamp on the dir inode will match
that of the leaf block for the most recent insertion/deletion.

For backwards compatibility, any of these new fields which is
zero should be considered to be "unknown".
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

For most cases, only a single new block is needed when we reach
the point of converting from stuffed to exhash directory. The
exception being when the file name is so long that it will not
fit within the new leaf block.

So this patch adds a simple test for that situation so that we
do not need to request the full reservation size in this case.

Potentially we could calculate more accurately the value to use
in other cases too, but that is much more complicated to do and
it is doubtful that the benefit would outweigh the extra cost
in code complexity.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch calls get_write_access in function gfs2_setattr_chown,
which merely increases inode->i_writecount for the duration of the
function. That will ensure that any file closes won't delete the
inode's multi-block reservation while the function is running.
It also ensures that a multi-block reservation exists when needed
for quota change operations during the chown.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

When we look to see if there is enough space to add a dir
entry without allocation, we have then been repeating the
same search later when we do the actual insertion. This
patch caches the details of the location in the gfs2_diradd
structure, so that we do not have to repeat the search.

This will provide a performance improvement which will be
greater as the size of the directory increases.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

There are three cases where we need to calculate the number of
blocks to reserve in a transaction involving linking an inode
into a directory. The one in rename is a bit more complicated,
but the basis of it is the same as for link and create. So it
makes sense to move this calculation into a single function
rather than repeating it three times.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The intent is that this structure will hold the information
required when adding entries to a directory (linking). To
start with, it will contain only the number of blocks which
are required to link the new entry into the directory. The
current calculation returns either 0 or the maximim number of
blocks that can ever be requested by such a transaction.

The intent is that in a later patch, we can update the dir
code to calculate this value more accurately. In addition
further patches will also add further fields to the new
structure to increase its utility.

In addition this patch fixes a bug where the link used during
inode creation was adding requesting too many blocks in
some cases. This is harmless unless the fs is close to being
full.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Prior to this patch, GFS2 had one address space for each rgrp,
stored in the glock. This patch changes them to use a single
address space in the super block. This therefore saves
(sizeof(struct address_space) * nr_of_rgrps) bytes of memory
and for large filesystems, that can be significant.

It would be nice to be able to do something similar and merge
the inode metadata address space into the same global
address space. However, that is rather more complicated as the
on-disk location doesn't have a 1:1 mapping with the inodes in
general. So while it could be done, it will be a more complicated
operation as it requires changing a lot more code paths.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Each rgrp header is represented as a single extent on disk, so we
can calculate the position within the address space, since we are
using address spaces mapped 1:1 to the disk. This means that it
is possible to use the range based versions of filemap_fdatawrite/wait
and for invalidating the page cache.

Our eventual intent is to then be able to merge the address spaces
used for rgrps into a single address space, rather than to have
one for each glock, saving memory and reducing complexity.

Since during umount, the rgrp structures are disposed of before
the glocks, we need to store the extent information in the glock
so that is is available for a final invalidation. This patch uses
a field which is otherwise unused in rgrp glocks to do that, so
that we do not have to expand the size of a glock.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Since gfs2_inplace_reserve() is always called with a valid
alloc parms structure, there is no need to test for this
within the function itself - and in any case, after we've
all ready dereferenced it anyway.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

There is only one place this is used, when reading in the quota
changes at mount time. It is not really required and much
simpler to just convert the fields from the on-disk structure
as required.

There should be no functional change as a result of this patch.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

For historical reasons, we drop and retake the log lock in ->releasepage()
however, since there is no reason why we cannot hold the log lock over
the whole function, this allows some simplification. In particular,
pinning a buffer is only ever done under the log lock, so it is possible
here to remove the test for pinned buffers in the second loop, since it
is impossible for that to happen (it is also tested in the first loop).

As a result, two tests made later in the second loop become constants
and can also be reduced to the only possible branch. So the net result
is to remove various bits of unreachable code and make this more
readable.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

With the preceding patch, we started accepting block reservations
smaller than the ideal size, which requires a lot more parsing of the
bitmaps. To reduce the amount of bitmap searching, this patch
implements a scheme whereby each rgrp keeps track of the point
at this multi-block reservations will fail.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This is just basically a resend of a patch I posted earlier.
It didn't change from its original, except in diff offsets, etc:

This patch fixes a bug in the GFS2 block allocation code. The problem
starts if a process already has a multi-block reservation, but for
some reason, another process disqualifies it from further allocations.
For example, the other process might set on the GFS2_RDF_ERROR bit.
The process holding the reservation jumps to label skip_rgrp, but
that label comes after the code that removes the reservation from the
tree. Therefore, the no longer usable reservation is not removed from
the rgrp's reservations tree; it's lost. Eventually, the lost reservation
causes the count of reserved blocks to get off, and eventually that
causes a BUG_ON(rs->rs_rbm.rgd->rd_reserved < rs->rs_free) to trigger.
This patch moves the call to after label skip_rgrp so that the
disqualified reservation is properly removed from the tree, thus keeping
the rgrp rd_reserved count sane.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Here is a second try at a patch I posted earlier, which also implements
suggestions Steve made:

Before this patch, GFS2 would keep searching through all the rgrps
until it found one that had a chunk of free blocks big enough to
satisfy the size hint, which is based on the file write size,
regardless of whether the chunk was big enough to perform the write.
However, when doing big writes there may not be a large enough
chunk of free blocks in any rgrp, due to file system fragmentation.
The largest chunk may be big enough to satisfy the write request,
but it may not meet the ideal reservation size from the "size hint".
The writes would slow to a crawl because every write would search
every rgrp, then finally give up and default to a single-block write.
In my case, performance would drop from 425MB/s to 18KB/s, or 24000
times slower.

This patch basically makes it so that if we can't find a contiguous
chunk of blocks big enough to satisfy the sizehint, we'll use the
largest chunk of blocks we found that will still contain the write.
It does so by keeping track of the largest run of blocks within the
rgrp.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The EPOLL_CTL_DEL path of epoll contains a classic, ab-ba deadlock.
That is, epoll_ctl(a, EPOLL_CTL_DEL, b, x), will deadlock with
epoll_ctl(b, EPOLL_CTL_DEL, a, x).  The deadlock was introduced with
commmit 67347fe4 ("epoll: do not take global 'epmutex' for simple
topologies").

The acquistion of the ep->mtx for the destination 'ep' was added such
that a concurrent EPOLL_CTL_ADD operation would see the correct state of
the ep (Specifically, the check for '!list_empty(&f.file->f_ep_links')

However, by simply not acquiring the lock, we do not serialize behind
the ep->mtx from the add path, and thus may perform a full path check
when if we had waited a little longer it may not have been necessary.
However, this is a transient state, and performing the full loop
checking in this case is not harmful.

The important point is that we wouldn't miss doing the full loop
checking when required, since EPOLL_CTL_ADD always locks any 'ep's that
its operating upon.  The reason we don't need to do lock ordering in the
add path, is that we are already are holding the global 'epmutex'
whenever we do the double lock.  Further, the original posting of this
patch, which was tested for the intended performance gains, did not
perform this additional locking.
Signed-off-by: NJason Baron <jbaron@akamai.com>
Cc: Nathan Zimmer <nzimmer@sgi.com>
Cc: Eric Wong <normalperson@yhbt.net>
Cc: Nelson Elhage <nelhage@nelhage.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Set FILE_CREATED on O_CREAT|O_EXCL.

cifs code didn't change during commit 116cc022

Kernel bugzilla 66251
Signed-off-by: NShirish Pargaonkar <spargaonkar@suse.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
CC: Stable <stable@kernel.org>
Signed-off-by: NSteve French <smfrench@gmail.com>

When we obtain tcon from cifs_sb, we use cifs_sb_tlink() to first obtain
tlink which also grabs a reference to it. We do not drop this reference
to tlink once we are done with the call.

The patch fixes this issue by instead passing tcon as a parameter and
avoids having to obtain a reference to the tlink. A lookup for the tcon
is already made in the calling functions and this way we avoid having to
re-run the lookup. This is also consistent with the argument list for
other similar calls for M-F symlinks.

We should also return an ENOSYS when we do not find a protocol specific
function to lookup the MF Symlink data.
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Reviewed-by: NJeff Layton <jlayton@redhat.com>
CC: Stable <stable@kernel.org>
Signed-off-by: NSteve French <smfrench@gmail.com>

Signed-off-by: NSteve French <smfrench@gmail.com>
Signed-off-by: NGregor Beck <gbeck@sernet.de>
Reviewed-by: NJeff Layton <jlayton@redhat.com>

Since commit 36bc08cc ("fs/aio: Add support to aio ring pages
migration") the aio ring setup code has used a special per-ring backing
inode for the page allocations, rather than just using random anonymous
pages.

However, rather than remembering the pages as it allocated them, it
would allocate the pages, insert them into the file mapping (dirty, so
that they couldn't be free'd), and then forget about them.  And then to
look them up again, it would mmap the mapping, and then use
"get_user_pages()" to get back an array of the pages we just created.

Now, not only is that incredibly inefficient, it also leaked all the
pages if the mmap failed (which could happen due to excessive number of
mappings, for example).

So clean it all up, making it much more straightforward.  Also remove
some left-overs of the previous (broken) mm_populate() usage that was
removed in commit d6c355c7 ("aio: fix race in ring buffer page
lookup introduced by page migration support") but left the pointless and
now misleading MAP_POPULATE flag around.
Tested-and-acked-by: NBenjamin LaHaise <bcrl@kvack.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The arbitrary restriction on page counts offered by the core
migrate_page_move_mapping() code results in rather suspicious looking
fiddling with page reference counts in the aio_migratepage() operation.
To fix this, make migrate_page_move_mapping() take an extra_count parameter
that allows aio to tell the code about its own reference count on the page
being migrated.

While cleaning up aio_migratepage(), make it validate that the old page
being passed in is actually what aio_migratepage() expects to prevent
misbehaviour in the case of races.
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>

e34ecee2 reworked the percpu reference
counting to correct a bug trinity found.  Unfortunately, the change lead
to kioctxes being leaked because there was no final reference count to
put.  Add that reference count back in to fix things.
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
Cc: stable@vger.kernel.org

Some pstore backing devices use on board flash as persistent
storage. These have limited numbers of write cycles so it
is a poor idea to use them from high frequency operations.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The missing casts can cause the high 64-bits of the physical blocks to
be lost.  Set up new macros which allows us to make sure the right
thing happen, even if at some point we end up supporting larger
logical block numbers.

Thanks to the Emese Revfy and the PaX security team for reporting this
issue.
Reported-by: NPaX Team <pageexec@freemail.hu>
Reported-by: Emese Revfy <re.emese@gmail.com>                                 
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

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: NSteven Whitehouse <swhiteho@redhat.com>

In patch 209806ab 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: NSteven Whitehouse <swhiteho@redhat.com>

Akira-san has been reporting rare deadlocks of his machine when running
xfstests test 269 on ext4 filesystem. The problem turned out to be in
ext4_da_reserve_metadata() and ext4_da_reserve_space() which called
ext4_should_retry_alloc() while holding i_data_sem. Since
ext4_should_retry_alloc() can force a transaction commit, this is a
lock ordering violation and leads to deadlocks.

Fix the problem by just removing the retry loops. These functions should
just report ENOSPC to the caller (e.g. ext4_da_write_begin()) and that
function must take care of retrying after dropping all necessary locks.
Reported-and-tested-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Reviewed-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

If we are doing aysnc writeback of metadata, we can get write errors
but have nobody to report them to. At the moment, we simply attempt
to reissue the write from io completion in the hope that it's a
transient error.

When it's not a transient error, the buffer is stuck forever in
this loop, and we cannot break out of it. Eventually, unmount will
hang because the AIL cannot be emptied and everything goes downhill
from them.

To solve this problem, only retry the write IO once before aborting
it. We don't throw the buffer away because some transient errors can
last minutes (e.g.  FC path failover) or even hours (thin
provisioned devices that have run out of backing space) before they
go away. Hence we really want to keep trying until we can't try any
more.

Because the buffer was not cleaned, however, it does not get removed
from the AIL and hence the next pass across the AIL will start IO on
it again. As such, we still get the "retry forever" semantics that
we currently have, but we allow other access to the buffer in the
mean time. Meanwhile the filesystem can continue to modify the
buffer and relog it, so the IO errors won't hang the log or the
filesystem.

Now when we are pushing the AIL, we can see all these "permanent IO
error" buffers and we can issue a warning about failures before we
retry the IO. We can also catch these buffers when unmounting an
issue a corruption warning, too.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

When swalloc is specified as a mount option, allocations are
supposed to be aligned to the stripe width rather than the stripe
unit of the underlying filesystem. However, it does not do this.

What the implementation does is round up the allocation size to a
stripe width, hence ensuring that all allocations span a full stripe
width. It does not, however, ensure that that allocation is aligned
to a stripe width, and hence the allocations can span multiple
underlying stripes and so still see RMW cycles for things like
direct IO on MD RAID.

So, if the swalloc mount option is set, change the allocation
alignment in xfs_bmap_btalloc() to use the stripe width rather than
the stripe unit.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBen Myers <bpm@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

The xfsbdstrat helper is a small but useless wrapper for xfs_buf_iorequest that
handles the case of a shut down filesystem.  Most of the users have private,
uncached buffers that can just be freed in this case, but the complex error
handling in xfs_bioerror_relse messes up the case when it's called without
a locked buffer.

Remove xfsbdstrat and opencode the error handling in the callers.  All but
one can simply return an error and don't need to deal with buffer state,
and the one caller that cares about the buffer state could do with a major
cleanup as well, but we'll defer that to later.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBen Myers <bpm@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

The function xfs_bmap_isaeof() is used to indicate that an
allocation is occurring at or past the end of file, and as such
should be aligned to the underlying storage geometry if possible.

Commit 27a3f8f2 ("xfs: introduce xfs_bmap_last_extent") changed the
behaviour of this function for empty files - it turned off
allocation alignment for this case accidentally. Hence large initial
allocations from direct IO are not getting correctly aligned to the
underlying geometry, and that is cause write performance to drop in
alignment sensitive configurations.

Fix it by considering allocation into empty files as requiring
aligned allocation again.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

(cherry picked from commit f9b395a8)

xfs_quota(8) will hang up if trying to turn group/project quota off
before the user quota is off, this could be 100% reproduced by:
  # mount -ouquota,gquota /dev/sda7 /xfs
  # mkdir /xfs/test
  # xfs_quota -xc 'off -g' /xfs <-- hangs up
  # echo w > /proc/sysrq-trigger
  # dmesg

  SysRq : Show Blocked State
  task                        PC stack   pid father
  xfs_quota       D 0000000000000000     0 27574   2551 0x00000000
  [snip]
  Call Trace:
  [<ffffffff81aaa21d>] schedule+0xad/0xc0
  [<ffffffff81aa327e>] schedule_timeout+0x35e/0x3c0
  [<ffffffff8114b506>] ? mark_held_locks+0x176/0x1c0
  [<ffffffff810ad6c0>] ? call_timer_fn+0x2c0/0x2c0
  [<ffffffffa0c25380>] ? xfs_qm_shrink_count+0x30/0x30 [xfs]
  [<ffffffff81aa3306>] schedule_timeout_uninterruptible+0x26/0x30
  [<ffffffffa0c26155>] xfs_qm_dquot_walk+0x235/0x260 [xfs]
  [<ffffffffa0c059d8>] ? xfs_perag_get+0x1d8/0x2d0 [xfs]
  [<ffffffffa0c05805>] ? xfs_perag_get+0x5/0x2d0 [xfs]
  [<ffffffffa0b7707e>] ? xfs_inode_ag_iterator+0xae/0xf0 [xfs]
  [<ffffffffa0c22280>] ? xfs_trans_free_dqinfo+0x50/0x50 [xfs]
  [<ffffffffa0b7709f>] ? xfs_inode_ag_iterator+0xcf/0xf0 [xfs]
  [<ffffffffa0c261e6>] xfs_qm_dqpurge_all+0x66/0xb0 [xfs]
  [<ffffffffa0c2497a>] xfs_qm_scall_quotaoff+0x20a/0x5f0 [xfs]
  [<ffffffffa0c2b8f6>] xfs_fs_set_xstate+0x136/0x180 [xfs]
  [<ffffffff8136cf7a>] do_quotactl+0x53a/0x6b0
  [<ffffffff812fba4b>] ? iput+0x5b/0x90
  [<ffffffff8136d257>] SyS_quotactl+0x167/0x1d0
  [<ffffffff814cf2ee>] ? trace_hardirqs_on_thunk+0x3a/0x3f
  [<ffffffff81abcd19>] system_call_fastpath+0x16/0x1b

It's fine if we turn user quota off at first, then turn off other
kind of quotas if they are enabled since the group/project dquot
refcount is decreased to zero once the user quota if off. Otherwise,
those dquots refcount is non-zero due to the user dquot might refer
to them as hint(s).  Hence, above operation cause an infinite loop
at xfs_qm_dquot_walk() while trying to purge dquot cache.

This problem has been around since Linux 3.4, it was introduced by:
  [ b84a3a96 xfs: remove the per-filesystem list of dquots ]

Originally we will release the group dquot pointers because the user
dquots maybe carrying around as a hint via xfs_qm_detach_gdquots().
However, with above change, there is no such work to be done before
purging group/project dquot cache.

In order to solve this problem, this patch introduces a special routine
xfs_qm_dqpurge_hints(), and it would release the group/project dquot
pointers the user dquots maybe carrying around as a hint, and then it
will proceed to purge the user dquot cache if requested.

Cc: stable@vger.kernel.org
Signed-off-by: NJie Liu <jeff.liu@oracle.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

(cherry picked from commit df8052e7)

For CRC enabled v5 super block, change a file's ownership can simply
trigger an ASSERT failure at xfs_setattr_nonsize() if both group and
project quota are enabled, i.e,

[  305.337609] XFS: Assertion failed: !XFS_IS_PQUOTA_ON(mp), file: fs/xfs/xfs_iops.c, line: 621
[  305.339250] Kernel BUG at ffffffffa0a7fa32 [verbose debug info unavailable]
[  305.383939] Call Trace:
[  305.385536]  [<ffffffffa0a7d95a>] xfs_setattr_nonsize+0x69a/0x720 [xfs]
[  305.387142]  [<ffffffffa0a7dea9>] xfs_vn_setattr+0x29/0x70 [xfs]
[  305.388727]  [<ffffffff811ca388>] notify_change+0x1a8/0x350
[  305.390298]  [<ffffffff811ac39d>] chown_common+0xfd/0x110
[  305.391868]  [<ffffffff811ad6bf>] SyS_fchownat+0xaf/0x110
[  305.393440]  [<ffffffff811ad760>] SyS_lchown+0x20/0x30
[  305.394995]  [<ffffffff8170f7dd>] system_call_fastpath+0x1a/0x1f
[  305.399870] RIP  [<ffffffffa0a7fa32>] assfail+0x22/0x30 [xfs]

This fix adjust the assertion to check if the super block support both
quota inodes or not.
Signed-off-by: NJie Liu <jeff.liu@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

(cherry picked from commit 5a01dd54)