quota: remove SLAB_MEM_SPREAD flag usage

The SLAB_MEM_SPREAD flag is already a no-op after removal of SLAB
allocator and in [1] it was fully deprecated. Remove its usage so we can
delete it from slab. No functional change.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-1-02f1753e8303@suse.cz/
Message-Id: <20240224135118.830073-1-chengming.zhou@linux.dev>

quota: Properly annotate i_dquot arrays with __rcu

Dquots pointed to from i_dquot arrays in inodes are protected by
dquot_srcu. Annotate them as such and change .get_dquots callback to
return properly annotated pointer to make sparse happy.

Fixes: b9ba6f94b238 ("quota: remove dqptr_sem")
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix rcu annotations of inode dquot pointers

Dquot pointers in i_dquot array in the inode are protected by
dquot_srcu. Annotate the array pointers with __rcu, perform the locked
dereferences with srcu_dereference_check() instead of plain reads, and
set the array elements with rcu_assign_pointer().

Fixes: b9ba6f94b238 ("quota: remove dqptr_sem")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402061900.rTuYDlo6-lkp@intel.com/
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix potential NULL pointer dereference

Below race may cause NULL pointer dereference

P1 P2
dquot_free_inode quota_off
drop_dquot_ref
remove_dquot_ref
dquots = i_dquot(inode)
dquots = i_dquot(inode)
srcu_read_lock
dquots[cnt]) != NULL (1)
dquots[type] = NULL (2)
spin_lock(&dquots[cnt]->dq_dqb_lock) (3)
....

If dquot_free_inode(or other routines) checks inode's quota pointers (1)
before quota_off sets it to NULL(2) and use it (3) after that, NULL pointer
dereference will be triggered.

So let's fix it by using a temporary pointer to avoid this issue.

Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240202081852.2514092-1-wangjianjian3@huawei.com>

quota: Remove BUG_ON from dqget()

dqget() checks whether dquot->dq_sb is set when returning it using
BUG_ON. Firstly this doesn't work as an invalidation check for quite
some time (we release dquot with dq_sb set these days), secondly using
BUG_ON is quite harsh. Use WARN_ON_ONCE and check whether dquot is still
hashed instead.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Remove BUG_ON in dquot_load_quota_sb()

The case when someone passes DQUOT_SUSPENDED flag to
dquot_load_quota_sb() is easy to handle. So just WARN_ON_ONCE and bail
with error if that happens instead of calling BUG_ON which is likely to
lockup the machine.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Replace BUG_ON in dqput()

The BUG_ON in dqput() will likely take the whole machine down when it
hits. Replace it with WARN_ON_ONCE() instead and stop hiding that behind
CONFIG_QUOTA_DEBUG.

Signed-off-by: Jan Kara <jack@suse.cz>

mm, slab: remove last vestiges of SLAB_MEM_SPREAD

Yes, yes, I know the slab people were planning on going slow and letting
every subsystem fight this thing on their own. But let's just rip off
the band-aid and get it over and done with. I don't want to see a
number of unnecessary pull requests just to get rid of a flag that no
longer has any meaning.

This was mainly done with a couple of 'sed' scripts and then some manual
cleanup of the end result.

Link: https://lore.kernel.org/all/CAHk-=wji0u+OOtmAOD-5JV3SXcRJF___k_+8XNKmak0yd5vW1Q@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs: Remove the now superfluous sentinel elements from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel elements ctl_table struct. Special attention was placed in
making sure that an empty directory for fs/verity was created when
CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not defined. In this case we use the
register sysctl call that expects a size.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

quota: convert dquot_claim_space_nodirty() to return void

dquot_claim_space_nodirty() always return zero, let's convert it
to return void, then, its caller can get rid of handling failure
case.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20231210025028.3262900-1-chao@kernel.org>

quota: dynamically allocate the dquota-cache shrinker

Use new APIs to dynamically allocate the dquota-cache shrinker.

Link: https://lkml.kernel.org/r/20230911094444.68966-14-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

quota: explicitly forbid quota files from being encrypted

Since commit d7e7b9af104c ("fscrypt: stop using keyrings subsystem for
fscrypt_master_key"), xfstest generic/270 causes a WARNING when run on
f2fs with test_dummy_encryption in the mount options:

$ kvm-xfstests -c f2fs/encrypt generic/270
[...]
WARNING: CPU: 1 PID: 2453 at fs/crypto/keyring.c:240 fscrypt_destroy_keyring+0x1f5/0x260

The cause of the WARNING is that not all encrypted inodes have been
evicted before fscrypt_destroy_keyring() is called, which violates an
assumption. This happens because the test uses an external quota file,
which gets automatically encrypted due to test_dummy_encryption.

Encryption of quota files has never really been supported. On ext4,
ext4_quota_read() does not decrypt the data, so encrypted quota files
are always considered invalid on ext4. On f2fs, f2fs_quota_read() uses
the pagecache, so trying to use an encrypted quota file gets farther,
resulting in the issue described above being possible. But this was
never intended to be possible, and there is no use case for it.

Therefore, make the quota support layer explicitly reject using
IS_ENCRYPTED inodes when quotaon is attempted.

Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230905003227.326998-1-ebiggers@kernel.org>

quota: Fix slow quotaoff

Eric has reported that commit dabc8b207566 ("quota: fix dqput() to
follow the guarantees dquot_srcu should provide") heavily increases
runtime of generic/270 xfstest for ext4 in nojournal mode. The reason
for this is that ext4 in nojournal mode leaves dquots dirty until the last
dqput() and thus the cleanup done in quota_release_workfn() has to write
them all. Due to the way quota_release_workfn() is written this results
in synchronize_srcu() call for each dirty dquot which makes the dquot
cleanup when turning quotas off extremely slow.

To be able to avoid synchronize_srcu() for each dirty dquot we need to
rework how we track dquots to be cleaned up. Instead of keeping the last
dquot reference while it is on releasing_dquots list, we drop it right
away and mark the dquot with new DQ_RELEASING_B bit instead. This way we
can we can remove dquot from releasing_dquots list when new reference to
it is acquired and thus there's no need to call synchronize_srcu() each
time we drop dq_list_lock.

References: https://lore.kernel.org/all/ZRytn6CxFK2oECUt@debian-BULLSEYE-live-builder-AMD64
Reported-by: Eric Whitney <enwlinux@gmail.com>
Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>

quota: use lockdep_assert_held_write in dquot_load_quota_sb

Use lockdep_assert_held_write to assert and self-document the locking
state in dquot_load_quota_sb instead of hand-crafting it with a trylock.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230802115439.2145212-2-hch@lst.de>

quota: simplify drop_dquot_ref()

As Honza said, remove_inode_dquot_ref() currently does not release the
last dquot reference but instead adds the dquot to tofree_head list. This
is because dqput() can sleep while dropping of the last dquot reference
(writing back the dquot and calling ->release_dquot()) and that must not
happen under dq_list_lock. Now that dqput() queues the final dquot cleanup
into a workqueue, remove_inode_dquot_ref() can call dqput() unconditionally
and we can significantly simplify it.

Here we open code the simplified code of remove_inode_dquot_ref() into
remove_dquot_ref() and remove the function put_dquot_list() which is no
longer used.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-6-libaokun1@huawei.com>

quota: fix dqput() to follow the guarantees dquot_srcu should provide

The dquot_mark_dquot_dirty() using dquot references from the inode
should be protected by dquot_srcu. quota_off code takes care to call
synchronize_srcu(&dquot_srcu) to not drop dquot references while they
are used by other users. But dquot_transfer() breaks this assumption.
We call dquot_transfer() to drop the last reference of dquot and add
it to free_dquots, but there may still be other users using the dquot
at this time, as shown in the function graph below:

cpu1 cpu2
_________________|_________________
wb_do_writeback CHOWN(1)
...
ext4_da_update_reserve_space
dquot_claim_block
...
dquot_mark_dquot_dirty // try to dirty old quota
test_bit(DQ_ACTIVE_B, &dquot->dq_flags) // still ACTIVE
if (test_bit(DQ_MOD_B, &dquot->dq_flags))
// test no dirty, wait dq_list_lock
...
dquot_transfer
__dquot_transfer
dqput_all(transfer_from) // rls old dquot
dqput // last dqput
dquot_release
clear_bit(DQ_ACTIVE_B, &dquot->dq_flags)
atomic_dec(&dquot->dq_count)
put_dquot_last(dquot)
list_add_tail(&dquot->dq_free, &free_dquots)
// add the dquot to free_dquots
if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
add dqi_dirty_list // add released dquot to dirty_list

This can cause various issues, such as dquot being destroyed by
dqcache_shrink_scan() after being added to free_dquots, which can trigger
a UAF in dquot_mark_dquot_dirty(); or after dquot is added to free_dquots
and then to dirty_list, it is added to free_dquots again after
dquot_writeback_dquots() is executed, which causes the free_dquots list to
be corrupted and triggers a UAF when dqcache_shrink_scan() is called for
freeing dquot twice.

As Honza said, we need to fix dquot_transfer() to follow the guarantees
dquot_srcu should provide. But calling synchronize_srcu() directly from
dquot_transfer() is too expensive (and mostly unnecessary). So we add
dquot whose last reference should be dropped to the new global dquot
list releasing_dquots, and then queue work item which would call
synchronize_srcu() and after that perform the final cleanup of all the
dquots on releasing_dquots.

Fixes: 4580b30ea887 ("quota: Do not dirty bad dquots")
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-5-libaokun1@huawei.com>

quota: add new helper dquot_active()

Add new helper function dquot_active() to make the code more concise.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-4-libaokun1@huawei.com>

quota: rename dquot_active() to inode_quota_active()

Now we have a helper function dquot_dirty() to determine if dquot has
DQ_MOD_B bit. dquot_active() can easily be misunderstood as a helper
function to determine if dquot has DQ_ACTIVE_B bit. So we avoid this by
renaming it to inode_quota_active() and later on we will add the helper
function dquot_active() to determine if dquot has DQ_ACTIVE_B bit.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-3-libaokun1@huawei.com>

quota: factor out dquot_write_dquot()

Refactor out dquot_write_dquot() to reduce duplicate code.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-2-libaokun1@huawei.com>

quota: Check presence of quota operation structures instead of ->quota_read and ->quota_write callbacks

Currently we check whether superblock has ->quota_read and ->quota_write
operations to check whether filesystem supports quotas. However for
example for shmfs we will not read or write dquots so check whether
quota operations are set in the superblock instead.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Message-Id: <20230725144510.253763-4-cem@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

quota: fix warning in dqgrab()

There's issue as follows when do fault injection:
WARNING: CPU: 1 PID: 14870 at include/linux/quotaops.h:51 dquot_disable+0x13b7/0x18c0
Modules linked in:
CPU: 1 PID: 14870 Comm: fsconfig Not tainted 6.3.0-next-20230505-00006-g5107a9c821af-dirty #541
RIP: 0010:dquot_disable+0x13b7/0x18c0
RSP: 0018:ffffc9000acc79e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88825e41b980
RDX: 0000000000000000 RSI: ffff88825e41b980 RDI: 0000000000000002
RBP: ffff888179f68000 R08: ffffffff82087ca7 R09: 0000000000000000
R10: 0000000000000001 R11: ffffed102f3ed026 R12: ffff888179f68130
R13: ffff888179f68110 R14: dffffc0000000000 R15: ffff888179f68118
FS: 00007f450a073740(0000) GS:ffff88882fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe96f2efd8 CR3: 000000025c8ad000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
dquot_load_quota_sb+0xd53/0x1060
dquot_resume+0x172/0x230
ext4_reconfigure+0x1dc6/0x27b0
reconfigure_super+0x515/0xa90
__x64_sys_fsconfig+0xb19/0xd20
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Above issue may happens as follows:
ProcessA ProcessB ProcessC
sys_fsconfig
vfs_fsconfig_locked
reconfigure_super
ext4_remount
dquot_suspend -> suspend all type quota

sys_fsconfig
vfs_fsconfig_locked
reconfigure_super
ext4_remount
dquot_resume
ret = dquot_load_quota_sb
add_dquot_ref
do_open -> open file O_RDWR
vfs_open
do_dentry_open
get_write_access
atomic_inc_unless_negative(&inode->i_writecount)
ext4_file_open
dquot_file_open
dquot_initialize
__dquot_initialize
dqget
atomic_inc(&dquot->dq_count);

__dquot_initialize
__dquot_initialize
dqget
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
ext4_acquire_dquot
-> Return error DQ_ACTIVE_B flag isn't set
dquot_disable
invalidate_dquots
if (atomic_read(&dquot->dq_count))
dqgrab
WARN_ON_ONCE(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
-> Trigger warning

In the above scenario, 'dquot->dq_flags' has no DQ_ACTIVE_B is normal when
dqgrab().
To solve above issue just replace the dqgrab() use in invalidate_dquots() with
atomic_inc(&dquot->dq_count).

Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230605140731.2427629-3-yebin10@huawei.com>

quota: Properly disable quotas when add_dquot_ref() fails

When add_dquot_ref() fails (usually due to IO error or ENOMEM), we want
to disable quotas we are trying to enable. However dquot_disable() call
was passed just the flags we are enabling so in case flags ==
DQUOT_USAGE_ENABLED dquot_disable() call will just fail with EINVAL
instead of properly disabling quotas. Fix the problem by always passing
DQUOT_LIMITS_ENABLED | DQUOT_USAGE_ENABLED to dquot_disable() in this
case.

Reported-and-tested-by: Ye Bin <yebin10@huawei.com>
Reported-by: syzbot+e633c79ceaecbf479854@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230605140731.2427629-2-yebin10@huawei.com>

quota: Use register_sysctl_init() for registering fs_dqstats_table

register_sysctl_init() also prints information that may be useful for
further debugging when we fail to register sysctl table. Use it when
registering fs_dqstats_table.

Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: make dquot_set_dqinfo return errors from ->write_info

dquot_set_dqinfo() ignores the return code from the ->write_info
call, which means that quotacalls like Q_SETINFO never see the error.
This doesn't seem right, so fix that.

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230227120216.31306-2-frank.li@vivo.com>

quota: simplify two-level sysctl registration for fs_dqstats_table

There is no need to declare two tables to just create directories,
this can be easily be done with a prefix path with register_sysctl().

Simplify this registration.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230310231206.3952808-4-mcgrof@kernel.org>

fs: port vfs{g,u}id helpers to mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

fs: port i_{g,u}id_{needs_}update() to mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

quota: port to mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

ext4: fix bug_on in __es_tree_search caused by bad quota inode

We got a issue as fllows:
==================================================================
kernel BUG at fs/ext4/extents_status.c:202!
invalid opcode: 0000 [#1] PREEMPT SMP
CPU: 1 PID: 810 Comm: mount Not tainted 6.1.0-rc1-next-g9631525255e3 #352
RIP: 0010:__es_tree_search.isra.0+0xb8/0xe0
RSP: 0018:ffffc90001227900 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000077512a0f RCX: 0000000000000000
RDX: 0000000000000002 RSI: 0000000000002a10 RDI: ffff8881004cd0c8
RBP: ffff888177512ac8 R08: 47ffffffffffffff R09: 0000000000000001
R10: 0000000000000001 R11: 00000000000679af R12: 0000000000002a10
R13: ffff888177512d88 R14: 0000000077512a10 R15: 0000000000000000
FS: 00007f4bd76dbc40(0000)GS:ffff88842fd00000(0000)knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005653bf993cf8 CR3: 000000017bfdf000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ext4_es_cache_extent+0xe2/0x210
ext4_cache_extents+0xd2/0x110
ext4_find_extent+0x5d5/0x8c0
ext4_ext_map_blocks+0x9c/0x1d30
ext4_map_blocks+0x431/0xa50
ext4_getblk+0x82/0x340
ext4_bread+0x14/0x110
ext4_quota_read+0xf0/0x180
v2_read_header+0x24/0x90
v2_check_quota_file+0x2f/0xa0
dquot_load_quota_sb+0x26c/0x760
dquot_load_quota_inode+0xa5/0x190
ext4_enable_quotas+0x14c/0x300
__ext4_fill_super+0x31cc/0x32c0
ext4_fill_super+0x115/0x2d0
get_tree_bdev+0x1d2/0x360
ext4_get_tree+0x19/0x30
vfs_get_tree+0x26/0xe0
path_mount+0x81d/0xfc0
do_mount+0x8d/0xc0
__x64_sys_mount+0xc0/0x160
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
==================================================================

Above issue may happen as follows:
-------------------------------------
ext4_fill_super
ext4_orphan_cleanup
ext4_enable_quotas
ext4_quota_enable
ext4_iget --> get error inode <5>
ext4_ext_check_inode --> Wrong imode makes it escape inspection
make_bad_inode(inode) --> EXT4_BOOT_LOADER_INO set imode
dquot_load_quota_inode
vfs_setup_quota_inode --> check pass
dquot_load_quota_sb
v2_check_quota_file
v2_read_header
ext4_quota_read
ext4_bread
ext4_getblk
ext4_map_blocks
ext4_ext_map_blocks
ext4_find_extent
ext4_cache_extents
ext4_es_cache_extent
__es_tree_search.isra.0
ext4_es_end --> Wrong extents trigger BUG_ON

In the above issue, s_usr_quota_inum is set to 5, but inode<5> contains
incorrect imode and disordered extents. Because 5 is EXT4_BOOT_LOADER_INO,
the ext4_ext_check_inode check in the ext4_iget function can be bypassed,
finally, the extents that are not checked trigger the BUG_ON in the
__es_tree_search function. To solve this issue, check whether the inode is
bad_inode in vfs_setup_quota_inode().

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221026042310.3839669-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

mm: shrinkers: provide shrinkers with names

Currently shrinkers are anonymous objects. For debugging purposes they
can be identified by count/scan function names, but it's not always
useful: e.g. for superblock's shrinkers it's nice to have at least an
idea of to which superblock the shrinker belongs.

This commit adds names to shrinkers. register_shrinker() and
prealloc_shrinker() functions are extended to take a format and arguments
to master a name.

In some cases it's not possible to determine a good name at the time when
a shrinker is allocated. For such cases shrinker_debugfs_rename() is
provided.

The expected format is:
<subsystem>-<shrinker_type>[:<instance>]-<id>
For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair.

After this change the shrinker debugfs directory looks like:
$ cd /sys/kernel/debug/shrinker/
$ ls
dquota-cache-16 sb-devpts-28 sb-proc-47 sb-tmpfs-42
mm-shadow-18 sb-devtmpfs-5 sb-proc-48 sb-tmpfs-43
mm-zspool:zram0-34 sb-hugetlbfs-17 sb-pstore-31 sb-tmpfs-44
rcu-kfree-0 sb-hugetlbfs-33 sb-rootfs-2 sb-tmpfs-49
sb-aio-20 sb-iomem-12 sb-securityfs-6 sb-tracefs-13
sb-anon_inodefs-15 sb-mqueue-21 sb-selinuxfs-22 sb-xfs:vda1-36
sb-bdev-3 sb-nsfs-4 sb-sockfs-8 sb-zsmalloc-19
sb-bpf-32 sb-pipefs-14 sb-sysfs-26 thp-deferred_split-10
sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-1 thp-zero-9
sb-cgroup2-30 sb-proc-39 sb-tmpfs-27 xfs-buf:vda1-37
sb-configfs-23 sb-proc-41 sb-tmpfs-29 xfs-inodegc:vda1-38
sb-dax-11 sb-proc-45 sb-tmpfs-35
sb-debugfs-7 sb-proc-46 sb-tmpfs-40

[roman.gushchin@linux.dev: fix build warnings]
Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

attr: port attribute changes to new types

Now that we introduced new infrastructure to increase the type safety
for filesystems supporting idmapped mounts port the first part of the
vfs over to them.

This ports the attribute changes codepaths to rely on the new better
helpers using a dedicated type.

Before this change we used to take a shortcut and place the actual
values that would be written to inode->i_{g,u}id into struct iattr. This
had the advantage that we moved idmappings mostly out of the picture
early on but it made reasoning about changes more difficult than it
should be.

The filesystem was never explicitly told that it dealt with an idmapped
mount. The transition to the value that needed to be stored in
inode->i_{g,u}id appeared way too early and increased the probability of
bugs in various codepaths.

We know place the same value in struct iattr no matter if this is an
idmapped mount or not. The vfs will only deal with type safe
vfs{g,u}id_t. This makes it massively safer to perform permission checks
as the type will tell us what checks we need to perform and what helpers
we need to use.

Fileystems raising FS_ALLOW_IDMAP can't simply write ia_vfs{g,u}id to
inode->i_{g,u}id since they are different types. Instead they need to
use the dedicated vfs{g,u}id_to_k{g,u}id() helpers that map the
vfs{g,u}id into the filesystem.

The other nice effect is that filesystems like overlayfs don't need to
care about idmappings explicitly anymore and can simply set up struct
iattr accordingly directly.

Link: https://lore.kernel.org/lkml/CAHk-=win6+ahs1EwLkcq8apqLi_1wXFWbrPf340zYEhObpz4jA@mail.gmail.com [1]
Link: https://lore.kernel.org/r/20220621141454.2914719-9-brauner@kernel.org
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

quota: port quota helpers mount ids

Port the is_quota_modification() and dqout_transfer() helper to type
safe vfs{g,u}id_t. Since these helpers are only called by a few
filesystems don't introduce a new helper but simply extend the existing
helpers to pass down the mount's idmapping.

Note, that this is a non-functional change, i.e. nothing will have
happened here or at the end of this series to how quota are done! This
a change necessary because we will at the end of this series make
ownership changes easier to reason about by keeping the original value
in struct iattr for both non-idmapped and idmapped mounts.

For now we always pass the initial idmapping which makes the idmapping
functions these helpers call nops.

This is done because we currently always pass the actual value to be
written to i_{g,u}id via struct iattr. While this allowed us to treat
the {g,u}id values in struct iattr as values that can be directly
written to inode->i_{g,u}id it also increases the potential for
confusion for filesystems.

Now that we are have dedicated types to prevent this confusion we will
ultimately only map the value from the idmapped mount into a filesystem
value that can be written to inode->i_{g,u}id when the filesystem
actually updates the inode. So pass down the initial idmapping until we
finished that conversion at which point we pass down the mount's
idmapping.

Since struct iattr uses an anonymous union with overlapping types as
supported by the C standard, filesystems that haven't converted to
ia_vfs{g,u}id won't see any difference and things will continue to work
as before. In other words, no functional changes intended with this
change.

Link: https://lore.kernel.org/r/20220621141454.2914719-7-brauner@kernel.org
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

fs: port to iattr ownership update helpers

Earlier we introduced new helpers to abstract ownership update and
remove code duplication. This converts all filesystems supporting
idmapped mounts to make use of these new helpers.

For now we always pass the initial idmapping which makes the idmapping
functions these helpers call nops.

This is done because we currently always pass the actual value to be
written to i_{g,u}id via struct iattr. While this allowed us to treat
the {g,u}id values in struct iattr as values that can be directly
written to inode->i_{g,u}id it also increases the potential for
confusion for filesystems.

Now that we are have dedicated types to prevent this confusion we will
ultimately only map the value from the idmapped mount into a filesystem
value that can be written to inode->i_{g,u}id when the filesystem
actually updates the inode. So pass down the initial idmapping until we
finished that conversion at which point we pass down the mount's
idmapping.

No functional changes intended.

Link: https://lore.kernel.org/r/20220621141454.2914719-6-brauner@kernel.org
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

quota: Prevent memory allocation recursion while holding dq_lock

As described in commit 02117b8ae9c0 ("f2fs: Set GF_NOFS in
read_cache_page_gfp while doing f2fs_quota_read"), we must not enter
filesystem reclaim while holding the dq_lock. Prevent this more generally
by using memalloc_nofs_save() while holding the lock.

Link: https://lore.kernel.org/r/20220605143815.2330891-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: make dquot_quota_sync return errors from ->sync_fs

Strangely, dquot_quota_sync ignores the return code from the ->sync_fs
call, which means that quotacalls like Q_SYNC never see the error. This
doesn't seem right, so fix that.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>

quota: Use 'hlist_for_each_entry' to simplify code

Use 'hlist_for_each_entry' instead of hand writing it.
This saves a few lines of code.

Link: https://lore.kernel.org/r/f82d3e33964dcbd2aac19866735e0a8381c8a735.1619599407.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jan Kara <jack@suse.cz>

fs: quota: fix array-index-out-of-bounds bug by passing correct argument to vfs_cleanup_quota_inode()

When dquot_resume() was last updated, the argument that got passed
to vfs_cleanup_quota_inode was incorrectly set.

If type = -1 and dquot_load_quota_sb() returns a negative value,
then vfs_cleanup_quota_inode() gets called with -1 passed as an
argument, and this leads to an array-index-out-of-bounds bug.

Fix this issue by correctly passing the arguments.

Fixes: ae45f07d47cc ("quota: Simplify dquot_resume()")
Link: https://lore.kernel.org/r/20201208194338.7064-1-anant.thazhemadam@gmail.com
Reported-by: syzbot+2643e825238d7aabb37f@syzkaller.appspotmail.com
Tested-by: syzbot+2643e825238d7aabb37f@syzkaller.appspotmail.com
CC: stable@vger.kernel.org
Signed-off-by: Anant Thazhemadam <anant.thazhemadam@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

block: move block-related definitions out of fs.h

Move most of the block related definition out of fs.h into more suitable
headers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

sysctl: pass kernel pointers to ->proc_handler

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from userspace in common code. This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs: avoid softlockups in s_inodes iterators

Anything that walks all inodes on sb->s_inodes list without rescheduling
risks softlockups.

Previous efforts were made in 2 functions, see:

c27d82f fs/drop_caches.c: avoid softlockups in drop_pagecache_sb()
ac05fbb inode: don't softlockup when evicting inodes

but there hasn't been an audit of all walkers, so do that now. This
also consistently moves the cond_resched() calls to the bottom of each
loop in cases where it already exists.

One loop remains: remove_dquot_ref(), because I'm not quite sure how
to deal with that one w/o taking the i_lock.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

new helper: lookup_positive_unlocked()

Most of the callers of lookup_one_len_unlocked() treat negatives are
ERR_PTR(-ENOENT). Provide a helper that would do just that. Note
that a pinned positive dentry remains positive - it's ->d_inode is
stable, etc.; a pinned _negative_ dentry can become positive at any
point as long as you are not holding its parent at least shared.
So using lookup_one_len_unlocked() needs to be careful;
lookup_positive_unlocked() is safer and that's what the callers
end up open-coding anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/quota: handle overflows of sysctl fs.quota.* and report as unsigned long

Quota statistics counted as 64-bit per-cpu counter. Reading sums per-cpu
fractions as signed 64-bit int, filters negative values and then reports
lower half as signed 32-bit int.

Result may looks like:

fs.quota.allocated_dquots = 22327
fs.quota.cache_hits = -489852115
fs.quota.drops = -487288718
fs.quota.free_dquots = 22083
fs.quota.lookups = -486883485
fs.quota.reads = 22327
fs.quota.syncs = 335064
fs.quota.writes = 3088689

Values bigger than 2^31-1 reported as negative.

All counters except "allocated_dquots" and "free_dquots" are monotonic,
thus they should be reported as is without filtering negative values.

Kernel doesn't have generic helper for 64-bit sysctl yet,
let's use at least unsigned long.

Link: https://lore.kernel.org/r/157337934693.2078.9842146413181153727.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Handle quotas without quota inodes in dquot_get_state()

Make dquot_get_state() gracefully handle a situation when there are no
quota files present even though quotas are enabled.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Make dquot_disable() work without quota inodes

Quota on and quota off are protected by s_umount semaphore held in
exclusive mode since commit 7d6cd73d33b6 "quota: Hold s_umount in
exclusive mode when enabling / disabling quotas". This makes it
impossible for dquot_disable() to race with other enabling or disabling
of quotas. Simplify the cleanup done by dquot_disable() based on this
fact and also remove some stale comments. As a bonus this cleanup makes
dquot_disable() properly handle a case when there are no quota inodes.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Drop dquot_enable()

Now dquot_enable() has only two internal callers and both of them just
need to update quota flags and don't need most of checks. Just drop
dquot_enable() and fold necessary functionality into the two calling
places.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Rename vfs_load_quota_inode() to dquot_load_quota_inode()

Rename vfs_load_quota_inode() to dquot_load_quota_inode() to be
consistent with naming of other functions used for enabling quota
accounting from filesystems. Also export the function and add some
sanity checks to assure filesystems are calling the function properly.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Simplify dquot_resume()

We already have quota inode loaded when resuming quotas. Use
vfs_load_quota() to avoid some pointless churn with the quota inode.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Factor out setup of quota inode

Factor out setting up of quota inode and eventual error cleanup from
vfs_load_quota_inode(). This will simplify situation for filesystems
that don't have any quota inodes.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Check that quota is not dirty before release

There is a race window where quota was redirted once we drop dq_list_lock inside dqput(),
but before we grab dquot->dq_lock inside dquot_release()

TASK1 TASK2 (chowner)
->dqput()
we_slept:
spin_lock(&dq_list_lock)
if (dquot_dirty(dquot)) {
spin_unlock(&dq_list_lock);
dquot->dq_sb->dq_op->write_dquot(dquot);
goto we_slept
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
spin_unlock(&dq_list_lock);
dquot->dq_sb->dq_op->release_dquot(dquot);
dqget()
mark_dquot_dirty()
dqput()
goto we_slept;
}
So dquot dirty quota will be released by TASK1, but on next we_sleept loop
we detect this and call ->write_dquot() for it.
XFSTEST: https://github.com/dmonakhov/xfstests/commit/440a80d4cbb39e9234df4d7240aee1d551c36107

Link: https://lore.kernel.org/r/20191031103920.3919-2-dmonakhov@openvz.org
CC: stable@vger.kernel.org
Signed-off-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: fix livelock in dquot_writeback_dquots

Write only quotas which are dirty at entry.

XFSTEST: https://github.com/dmonakhov/xfstests/commit/b10ad23566a5bf75832a6f500e1236084083cddc

Link: https://lore.kernel.org/r/20191031103920.3919-1-dmonakhov@openvz.org
CC: stable@vger.kernel.org
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: code cleanup for hash bits calculation

Code cleanup for hash bits calculation by
calling ilog2().

Link: https://lore.kernel.org/r/20190923135223.27674-1-cgxu519@zoho.com.cn
Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: avoid increasing DQST_LOOKUPS when iterating over dirty/inuse list

It is meaningless to increase DQST_LOOKUPS number while iterating
over dirty/inuse list, so just avoid it.

Link: https://lore.kernel.org/r/20190926083408.4269-1-cgxu519@zoho.com.cn
Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: fix condition for resetting time limit in do_set_dqblk()

We reset time limit when current usage is smaller
or equal to soft limit in other place, so follow
this rule in do_set_dqblk().

Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Link: https://lore.kernel.org/r/20190724053216.19392-1-cgxu519@zoho.com.cn
Signed-off-by: Jan Kara <jack@suse.cz>

quota: fix a problem about transfer quota

Run below script as root, dquot_add_space will return -EDQUOT since
__dquot_transfer call dquot_add_space with flags=0, and dquot_add_space
think it's a preallocation. Fix it by set flags as DQUOT_SPACE_WARN.

mkfs.ext4 -O quota,project /dev/vdb
mount -o prjquota /dev/vdb /mnt
setquota -P 23 1 1 0 0 /dev/vdb
dd if=/dev/zero of=/mnt/test-file bs=4K count=1
chattr -p 23 test-file

Fixes: 7b9ca4c61bc2 ("quota: Reduce contention on dq_data_lock")
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: add dqi_dirty_list description to comment of Dquot List Management

Actually there are four lists for dquot management, so add
the description of dqui_dirty_list to comment.

Signed-off-by: Chengguang Xu <cgxu519@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: check time limit when back out space/inode change

When we fail from allocating inode/space, we back out
the change we already did. In a special case which has
exceeded soft limit by the change, we should also check
time limit and reset it properly.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/quota: erase unused but set variable warning

Local variable *reserved* of remove_dquot_ref() is only used if
define CONFIG_QUOTA_DEBUG, but not ebraced in CONFIG_QUOTA_DEBUG
macro, which leads to unused-but-set-variable warning when compiling.

This patch ebrace it into CONFIG_QUOTA_DEBUG macro like what is done
in add_dquot_ref().

Signed-off-by: Jiang Biao <benbjiang@tencent.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: fix wrong indentation

We need to check return code only when calling ->read_dqblk(),
so fix it properly.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: remove trailing whitespaces

This removes all trailing whitespaces in fs/quota/.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: code cleanup for __dquot_alloc_space()

Replace (flags & DQUOT_SPACE_RESERVE) with
variable reserve.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Cleanup list iteration in dqcache_shrink_scan()

Use list_first_entry() and list_empty() instead of opencoded variants.

Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: reclaim least recently used dquots

The dquots in the free_dquots list are not reclaimed in LRU way.
put_dquot_last() puts entries to the tail and dqcache_shrink_scan()
frees from the tail. Free unreferenced dquots in LRU order because it
seems more reasonable than freeing most recently used.

Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs: quota: Replace GFP_ATOMIC with GFP_KERNEL in dquot_init

dquot_init() is never called in atomic context.
This function is only set as a parameter of fs_initcall().

Despite never getting called from atomic context,
dquot_init() calls __get_free_pages() with GFP_ATOMIC,
which waits busily for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
to avoid busy waiting and improve the possibility of sucessful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Check for register_shrinker() failure.

register_shrinker() might return -ENOMEM error since Linux 3.12.
Call panic() as with other failure checks in this function if
register_shrinker() failed.

Fixes: 1d3d4437eae1 ("vmscan: per-node deferred work")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Jan Kara <jack@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Reviewed-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: propagate error from __dquot_initialize

In commit 6184fc0b8dd7 ("quota: Propagate error from ->acquire_dquot()"),
we have propagated error from __dquot_initialize to caller, but we forgot
to handle such error in add_dquot_ref(), so, currently, during quota
accounting information initialization flow, if we failed for some of
inodes, we just ignore such error, and do account for others, which is
not a good implementation.

In this patch, we choose to let user be aware of such error, so after
turning on quota successfully, we can make sure all inodes disk usage
can be accounted, which will be more reasonable.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: be aware of error from dquot_initialize

Commit 6184fc0b8dd7 ("quota: Propagate error from ->acquire_dquot()")
missed to handle error from dquot_initialize in dquot_file_open, fix it.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

quota: fix potential infinite loop

In dquot_writeback_dquots(), we write back dquot from dirty dquots
list. There is a potential infinite loop if ->write_dquot() failure
and forget remove dquot from the list. This patch clear dirty bit
anyway to avoid it.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Generate warnings for DQUOT_SPACE_NOFAIL allocations

Eryu has reported that since commit 7b9ca4c61bc2 "quota: Reduce
contention on dq_data_lock" test generic/233 occasionally fails. This is
caused by the fact that since that commit we don't generate warning and
set grace time for quota allocations that have DQUOT_SPACE_NOFAIL set
(these are for example some metadata allocations in ext4). We need these
allocations to behave regularly wrt warning generation and grace time
setting so fix the code to return to the original behavior.

Reported-and-tested-by: Eryu Guan <eguan@redhat.com>
CC: stable@vger.kernel.org
Fixes: 7b9ca4c61bc278b771fb57d6290a31ab1fc7fdac
Signed-off-by: Jan Kara <jack@suse.cz>

quota: add missing lock into __dquot_transfer()

Lock dq_dqb_lock around dquot_decr_inodes()

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: 7b9ca4c61bc2 ("quota: Reduce contention on dq_data_lock")
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Reduce contention on dq_data_lock

dq_data_lock is currently used to protect all modifications of quota
accounting information, consistency of quota accounting on the inode,
and dquot pointers from inode. As a result contention on the lock can be
pretty heavy.

Reduce the contention on the lock by protecting quota accounting
information by a new dquot->dq_dqb_lock and consistency of quota
accounting with inode usage by inode->i_lock.

This change reduces time to create 500000 files on ext4 on ramdisk by 50
different processes in separate directories by 6% when user quota is
turned on. When those 50 processes belong to 50 different users, the
improvement is about 9%.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Inline dquot_[re]claim_reserved_space() into callsite

dquot_claim_reserved_space() and dquot_reclaim_reserved_space() have
only a single callsite. Inline them there.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Inline inode_{incr,decr}_space() into callsites

inode_incr_space() and inode_decr_space() have only two callsites.
Inline them there as that will make locking changes simpler.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Inline functions into their callsites

inode_add_rsv_space() and inode_sub_rsv_space() had only one callsite.
Inline them there directly. inode_claim_rsv_space() and
inode_reclaim_rsv_space() had two callsites so inline them there as
well. This will simplify further locking changes.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Allow disabling tracking of dirty dquots in a list

Filesystems that are journalling quotas generally don't need tracking of
dirty dquots in a list since forcing a transaction commit flushes all
quotas anyway. Allow filesystem to say it doesn't want dquots to be
tracked as it reduces contention on the dq_list_lock.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Remove dq_wait_unused from dquot

Currently every dquot carries a wait_queue_head_t used only when we are
turning quotas off to wait for last users to drop dquot references.
Since such rare case is not performance sensitive in any means, just use
a global waitqueue for this and save space in struct dquot. Also convert
the logic to use wait_event() instead of open-coding it.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Move locking into clear_dquot_dirty()

Move locking of dq_list_lock into clear_dquot_dirty(). It makes the
function more self-contained and will simplify our life later.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Do not dirty bad dquots

Currently we mark dirty even dquots that are not active (i.e.,
initialization or reading failed for them). Thus later we have to check
whether dirty dquot is really active and just clear the dirty bit if
not. Avoid this complication by just never marking non-active dquot as
dirty.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix possible corruption of dqi_flags

dqi_flags modifications are protected by dq_data_lock. However the
modifications in vfs_load_quota_inode() and in mark_info_dirty() were
not which could lead to corruption of dqi_flags. Since modifications to
dqi_flags are rare, this is hard to observe in practice but in theory it
could happen. Fix the problem by always using dq_data_lock for
protection.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Push dqio_sem down to ->read_file_info()

Push down acquisition of dqio_sem into ->read_file_info() callback. This
is for consistency with other operations and it also allows us to get
rid of an ugliness in OCFS2.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Push dqio_sem down to ->write_file_info()

Push down acquisition of dqio_sem into ->write_file_info() callback.
Mostly for consistency with other operations.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Push dqio_sem down to ->get_next_id()

Push down acquisition of dqio_sem into ->get_next_id() callback. Mostly
for consistency with other operations.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Push dqio_sem down to ->release_dqblk()

Push down acquisition of dqio_sem into ->release_dqblk() callback. It
will allow quota formats to decide whether they need it or not.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Push dqio_sem down to ->write_dqblk()

Push down acquisition of dqio_sem into ->write_dqblk() callback. It will
allow quota formats to decide whether they need it or not.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Push dqio_sem down to ->read_dqblk()

Push down acquisition of dqio_sem into ->read_dqblk() callback. It will
allow quota formats to decide whether they need it or not.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Protect dquot writeout with dq_lock

Currently dquot writeout is only protected by dqio_sem held for writing.
As we transition to a finer grained locking we will use dquot->dq_lock
instead. So acquire it in dquot_commit() and move dqio_sem just around
->commit_dqblk() call as it is still needed to serialize quota file
changes.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Acquire dqio_sem for reading in vfs_load_quota_inode()

vfs_load_quota_inode() needs dqio_sem only for reading. In fact dqio_sem
is not needed there at all since the function can be called only during
quota on when quota file cannot be modified but let's leave the
protection there since it is logical and the path is in no way
performance critical.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Acquire dqio_sem for reading in dquot_get_next_id()

dquot_get_next_id() needs dqio_sem only for reading to protect against
racing with modification of quota file structure.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Do more fine-grained locking in dquot_acquire()

We need dqio_sem held just for reading when calling ->read_dqblk() in
dquot_acquire(). Also dqio_sem is not needed when setting DQ_READ_B and
DQ_ACTIVE_B as concurrent reads and dquot activations are serialized by
dq_lock. So acquire and release dqio_sem closer to the place where it is
needed. This reduces lock hold time and will make locking changes
easier.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Convert dqio_mutex to rwsem

Convert dqio_mutex to rwsem and call it dqio_sem. No functional changes
yet.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: correct space limit check

Currently we compare total space (curspace + rsvspace)
with space limit in quota-tools when setting grace time
and also in check_bdq(), but we missing rsvspace in
somewhere else, correct them. This patch also fix incorrect
zero dqb_btime and grace time updating failure when we use
rsvspace(e.g. ext4 dalloc feature).

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: add get_inode_usage callback to transfer multi-inode charges

Ext4 ea_inode feature allows storing xattr values in external inodes to
be able to store values that are bigger than a block in size. Ext4 also
has deduplication support for these type of inodes. With deduplication,
the actual storage waste is eliminated but the users of such inodes are
still charged full quota for the inodes as if there was no sharing
happening in the background.

This design requires ext4 to manually charge the users because the
inodes are shared.

An implication of this is that, if someone calls chown on a file that
has such references we need to transfer the quota for the file and xattr
inodes. Current dquot_transfer() function implicitly transfers one inode
charge. With ea_inode feature, we would like to transfer multiple inode
charges.

Add get_inode_usage callback which can interrogate the total number of
inodes that were charged for a given inode.

[ Applied fix from Colin King to make sure the 'ret' variable is
initialized on the successful return path. Detected by
CoverityScan, CID#1446616 ("Uninitialized scalar variable") --tytso]

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Jan Kara <jack@suse.cz>

ext4: fix quota charging for shared xattr blocks

ext4_xattr_block_set() calls dquot_alloc_block() to charge for an xattr
block when new references are made. However if dquot_initialize() hasn't
been called on an inode, request for charging is effectively ignored
because ext4_inode_info->i_dquot is not initialized yet.

Add dquot_initialize() to call paths that lead to ext4_xattr_block_set().

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

quota: Remove dquot_quotactl_ops

Nobody uses them anymore.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Stop setting IMMUTABLE and NOATIME flags on quota files

Currently we set IMMUTABLE and NOATIME flags on quota files to stop
userspace from messing with them. Now that all filesystems set these
flags in their quota_on handlers, we can stop setting the flags in
generic quota code. This will allow filesystems to stop copying i_flags
to their on-disk flags on various occasions.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>

sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>

Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

quota: Fix bogus warning in dquot_disable()

dquot_disable() was warning when sb_has_quota_loaded() was true when
invalidating page cache for quota files. The thinking behind this
warning was that we must have raced with somebody else turning quotas on
and this should not happen because all places modifying quota state must
hold s_umount exclusively now. However sb_has_quota_loaded() can be also
true at this point when we are just suspending quotas on remount
read-only. Just restore the behavior to situation before commit
c3b004460d77 ("quota: Remove dqonoff_mutex") which introduced the
warning.

The code in dquot_disable() can be further simplified with the new
locking of quota state changes however let's leave that to a separate
commit that can get more testing exposure.

Fixes: c3b004460d77bf3f980d877be539016f2df4df12
Signed-off-by: Jan Kara <jack@suse.cz>

quota: constify struct path in quota_on

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

quota: Remove dqonoff_mutex

The only places that were grabbing dqonoff_mutex are functions turning
quotas on and off and these are properly serialized using s_umount
semaphore. Remove dqonoff_mutex.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Remove dqonoff_mutex from dquot_scan_active()

All callers of dquot_scan_active() now hold s_umount so we can rely on
that lock to protect us against quota state changes.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Use s_umount protection for quota operations

Writeback quota is protected by s_umount semaphore held for reading
because every writeback must be protected by that lock (grabbed either
by the generic writeback code or by quotactl handler). Getting next
available ID in quota file, querying quota state, setting quota
information, getting quota format are all quotactl operations protected
by s_umount semaphore held for reading grabbed in quotactl handler.

This also fixes lockdep splat about possible deadlock during filesystem
freezing where sync_filesystem() is called with page-faults already
blocked but sync_filesystem() calls into dquot_writeback_dquots() which
grabs dqonoff_mutex which ranks above i_mutex (vfs_load_quota_inode()
grabs i_mutex under dqonoff_mutex) which clearly ranks below page fault
freeze protection (e.g. via mmap_sem dependencies). The reported problem
is not a real deadlock possibility since during quota on we check
whether filesystem freezing is not in progress but still it is good to
have this fixed.

Reported-by: Ted Tso <tytso@mit.edu>
Reported-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Hold s_umount in exclusive mode when enabling / disabling quotas

Currently we hold s_umount semaphore only in shared mode when enabling
or disabling quotas and use dqonoff_mutex for serializing quota state
changes on a filesystem and also quota state changes with other places
depending on current quota state. Using dedicated mutex for this causes
possible deadlocks during filesystem freezing (see following commit for
details) so we transition to using s_umount semaphore for the necessary
synchronization whose lock ordering is properly handled by the
filesystem freezing code. As a start grab s_umount in exclusive mode
when enabling / disabling quotas.

Signed-off-by: Jan Kara <jack@suse.cz>

dquot: For now explicitly don't support filesystems outside of init_user_ns

Mostly supporting filesystems outside of init_user_ns is
s/&init_usre_ns/dquot->dq_sb->s_user_ns/. An actual need for
supporting quotas on filesystems outside of s_user_ns is quite a ways
away and to be done responsibily needs an audit on what can happen
with hostile quota files. Until that audit is complete don't attempt
to support quota files on filesystems outside of s_user_ns.

Cc: Jan Kara <jack@suse.cz>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

quota: Ensure qids map to the filesystem

Introduce the helper qid_has_mapping and use it to ensure that the
quota system only considers qids that map to the filesystems
s_user_ns.

In practice for quota supporting filesystems today this is the exact
same check as qid_valid. As only 0xffffffff aka (qid_t)-1 does not
map into init_user_ns.

Replace the qid_valid calls with qid_has_mapping as values come in
from userspace. This is harmless today and it prepares the quota
system to work on filesystems with quotas but mounted by unprivileged
users.

Call qid_has_mapping from dqget. This ensures the passed in qid has a
prepresentation on the underlying filesystem. Previously this was
unnecessary as filesystesm never had qids that could not map. With
the introduction of filesystems outside of s_user_ns this will not
remain true.

All of this ensures the quota code never has to deal with qids that
don't map to the underlying filesystem.

Cc: Jan Kara <jack@suse.cz>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

quota: use time64_t internally

The quota subsystem has two formats, the old v1 format using architecture
specific time_t values on the on-disk format, while the v2 format
(introduced in Linux 2.5.16 and 2.4.22) uses fixed 64-bit little-endian.

While there is no future for the v1 format beyond y2038, the v2 format
is almost there on 32-bit architectures, as both the user interface
and the on-disk format use 64-bit timestamps, just not the time_t
inbetween.

This changes the internal representation to use time64_t, which will
end up doing the right thing everywhere for v2 format.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Handle Q_GETNEXTQUOTA when quota is disabled

Currently we oopsed when Q_GETNEXTQUOTA got called when quota was
disabled. Properly check whether quota is enabled for the filesystem
before calling into quota format handler.

Reported-by: Ted Tso <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: use lookup_one_len_unlocked()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

quota: Fix possible GPF due to uninitialised pointers

When dqget() in __dquot_initialize() fails e.g. due to IO error,
__dquot_initialize() will pass an array of uninitialized pointers to
dqput_all() and thus can lead to deference of random data. Fix the
problem by properly initializing the array.

CC: stable@vger.kernel.org
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix possible races during quota loading

When loading new quota structure from disk, there is a possibility caller
of dqget() will see uninitialized data due to CPU reordering loads or
stores - loads from dquot can be reordered before test of DQ_ACTIVE_B
bit or setting of this bit could be reordered before filling of the
structure. Fix the issue by adding proper memory barriers.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Add support for ->get_nextdqblk() for VFS quota

Add infrastructure for supporting get_nextdqblk() callback for VFS
quotas. Translate the operation into a callback to appropriate
filesystem and consequently to quota format callback.

Signed-off-by: Jan Kara <jack@suse.cz>

wrappers for ->i_mutex access

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs: make quota/dquot.c explicitly non-modular

The Kconfig currently controlling compilation of this code is:

config QUOTA
bool "Quota support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the couple traces of modularity so that when reading the
driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering gets bumped to one level earlier when we
use the more appropriate fs_initcall here. However we've made similar
changes before without any fallout and none is expected here either.

We don't delete module.h because the code in turn tries to load other
modules as appropriate and so it still needs that header.

Cc: Jan Kara <jack@suse.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Jan Kara <jack@suse.cz>

inode: convert inode_sb_list_lock to per-sb

The process of reducing contention on per-superblock inode lists
starts with moving the locking to match the per-superblock inode
list. This takes the global lock out of the picture and reduces the
contention problems to within a single filesystem. This doesn't get
rid of contention as the locks still have global CPU scope, but it
does isolate operations on different superblocks form each other.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dave Chinner <dchinner@redhat.com>

quota: Propagate error from ->acquire_dquot()

Currently when some error happened in ->acquire_dquot(), dqget() just
returned NULL. That was indistinguishable from a case when e.g. someone
run quotaoff and so was generally silently ignored. However
->acquire_dquot() can fail because of ENOSPC or EIO in which case user
should better know. So propagate error up from ->acquire_dquot properly.

Signed-off-by: Jan Kara <jack@suse.cz>

VFS: fs library helpers: d_inode() annotations

library helpers called by filesystem drivers on their own inodes

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

vfs: Add general support to enforce project quota limits

This patch adds support for a new quota type PRJQUOTA for project quota
enforcement. Also a new method get_projid() is added into dquot_operations
structure.

Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: optimize i_dquot access

Remove redundant calls of i_dquot(), keep pointer in local variable.

add/remove: 0/0 grow/shrink: 3/7 up/down: 40/-278 (-238)
function old new delta
__dquot_free_space 734 750 +16
__dquot_alloc_space 484 500 +16
dquot_free_inode 324 332 +8
dquot_drop 82 69 -13
vfs_load_quota_inode 1357 1341 -16
dquot_reclaim_space_nodirty 348 316 -32
dquot_disable 1980 1944 -36
dquot_claim_space_nodirty 354 314 -40
__dquot_drop 125 83 -42
__dquot_initialize 522 423 -99

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Make ->set_info use structure with neccesary info to VFS and XFS

Change ->set_info to take new qc_info structure which contains all the
necessary information both for XFS and VFS. Convert Q_SETINFO handler
to use this structure.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Make VFS quotas use new interface for getting quota info

Create new internal interface for getting information about quota which
contains everything needed for both VFS quotas and XFS quotas. Make VFS
use this and hook it up to Q_GETINFO.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Store maximum space limit in bytes

Currently maximum space limit quota format supports is in blocks however
since we store space limits in bytes, this is somewhat confusing. So
store the maximum limit in bytes as well. Also rename the field to match
the new unit and related inode field to match the new naming scheme.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Add ->quota_{enable,disable} callbacks for VFS quotas

Add functions which translate ->quota_enable / ->quota_disable calls
into appropriate changes in VFS quota. This will enable filesystems
supporting VFS quota files in system inodes to be controlled via
Q_XQUOTA[ON|OFF] quotactls for better userspace compatibility.

Also provide a vector for quotactl using these functions which can be
used by filesystems with quota files stored in hidden system files.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Switch ->get_dqblk() and ->set_dqblk() to use bytes as space units

Currently ->get_dqblk() and ->set_dqblk() use struct fs_disk_quota which
tracks space limits and usage in 512-byte blocks. However VFS quotas
track usage in bytes (as some filesystems require that) and we need to
somehow pass this information. Upto now it wasn't a problem because we
didn't do any unit conversion (thus VFS quota routines happily stuck
number of bytes into d_bcount field of struct fd_disk_quota). Only if
you tried to use Q_XGETQUOTA or Q_XSETQLIM for VFS quotas (or Q_GETQUOTA
/ Q_SETQUOTA for XFS quotas), you got bogus results. Hardly anyone
tried this but reportedly some Samba users hit the problem in practice.
So when we want interfaces compatible we need to fix this.

We bite the bullet and define another quota structure used for passing
information from/to ->get_dqblk()/->set_dqblk. It's somewhat sad we have
to have more conversion routines in fs/quota/quota.c and another copying
of quota structure slows down getting of quota information by about 2%
but it seems cleaner than overloading e.g. units of d_bcount to bytes.

CC: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Verify flags passed to Q_SETINFO

Currently flags passed via Q_SETINFO were just stored. This makes it
hard to add new flags since in theory userspace could be just setting /
clearing random flags. Since currently there is only one userspace
settable flag and that is somewhat obscure flags only for ancient v1
quota format, I'm reasonably sure noone operates these flags and
hopefully we are fine just adding the check that passed flags are sane.
If we indeed find some userspace program that gets broken by the strict
check, we can always remove it again.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Cleanup flags definitions

Currently all quota flags were defined just in kernel-private headers.
Export flags readable / writeable from userspace to userspace via
include/uapi/linux/quota.h.

Signed-off-by: Jan Kara <jack@suse.cz>

vfs: Remove i_dquot field from inode

All filesystems using VFS quotas are now converted to use their private
i_dquot fields. Remove the i_dquot field from generic inode structure.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Use function to provide i_dquot pointers

i_dquot array is used by relatively few filesystems (ext?, ocfs2, jfs,
reiserfs) so it is beneficial to move this array to fs-private part of
the inode. We cannot just pass quota pointers from filesystems to quota
functions because during quotaon and quotaoff we have to traverse list
of all inodes and manipulate i_dquot pointers for each inode. So we
provide a function which generic quota code can use to get pointer to
the i_dquot array from the filesystem.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Remove const from function declarations

We don't use const through VFS too much so just remove it from quota
function declarations.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Add log level to printk

JK: Added VFS: prefix to the message when changing it to make it more
standard.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Properly return errors from dquot_writeback_dquots()

Due to a switched left and right side of an assignment,
dquot_writeback_dquots() never returned error. This could result in
errors during quota writeback to not be reported to userspace properly.
Fix it.

CC: stable@vger.kernel.org
Coverity-id: 1226884
Signed-off-by: Jan Kara <jack@suse.cz>

percpu_counter: add @gfp to percpu_counter_init()

Percpu allocator now supports allocation mask. Add @gfp to
percpu_counter_init() so that !GFP_KERNEL allocation masks can be used
with percpu_counters too.

We could have left percpu_counter_init() alone and added
percpu_counter_init_gfp(); however, the number of users isn't that
high and introducing _gfp variants to all percpu data structures would
be quite ugly, so let's just do the conversion. This is the one with
the most users. Other percpu data structures are a lot easier to
convert.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: x86@kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>

quota: remove dqptr_sem

Remove dqptr_sem to make quota code scalable: Remove the dqptr_sem,
accessing inode->i_dquot now protected by dquot_srcu, and changing
inode->i_dquot is now serialized by dq_data_lock.

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: simplify remove_inode_dquot_ref()

Simplify the remove_inode_dquot_ref() to make it more obvious
that now we keep one reference for each dquot from inodes.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: avoid unnecessary dqget()/dqput() calls

Avoid unnecessary dqget()/dqput() calls in __dquot_initialize(),
that will introduce global lock contention otherwise.

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: missing lock in dqcache_shrink_scan()

Commit 1ab6c4997e04 (fs: convert fs shrinkers to new scan/count API)
accidentally removed locking from quota shrinker. Fix it -
dqcache_shrink_scan() should use dq_list_lock to protect the
scan on free_dquots list.

CC: stable@vger.kernel.org
Fixes: 1ab6c4997e04a00c50c6d786c2f046adc0d1f5de
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: provide function to grab quota structure reference

Provide dqgrab() function to get quota structure reference when we are
sure it already has at least one active reference. Make use of this
function inside quota code.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

quota: Fix race between dqput() and dquot_scan_active()

Currently last dqput() can race with dquot_scan_active() causing it to
call callback for an already deactivated dquot. The race is as follows:

CPU1 CPU2
dqput()
spin_lock(&dq_list_lock);
if (atomic_read(&dquot->dq_count) > 1) {
- not taken
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
spin_unlock(&dq_list_lock);
->release_dquot(dquot);
if (atomic_read(&dquot->dq_count) > 1)
- not taken
dquot_scan_active()
spin_lock(&dq_list_lock);
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
- not taken
atomic_inc(&dquot->dq_count);
spin_unlock(&dq_list_lock);
- proceeds to release dquot
ret = fn(dquot, priv);
- called for inactive dquot

Fix the problem by making sure possible ->release_dquot() is finished by
the time we call the callback and new calls to it will notice reference
dquot_scan_active() has taken and bail out.

CC: stable@vger.kernel.org # >= 2.6.29
Signed-off-by: Jan Kara <jack@suse.cz>

fs: convert fs shrinkers to new scan/count API

Convert the filesystem shrinkers to use the new API, and standardise some
of the behaviours of the shrinkers at the same time. For example,
nr_to_scan means the number of objects to scan, not the number of objects
to free.

I refactored the CIFS idmap shrinker a little - it really needs to be
broken up into a shrinker per tree and keep an item count with the tree
root so that we don't need to walk the tree every time the shrinker needs
to count the number of objects in the tree (i.e. all the time under
memory pressure).

[glommer@openvz.org: fixes for ext4, ubifs, nfs, cifs and glock. Fixes are needed mainly due to new code merged in the tree]
[assorted fixes folded in]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Glauber Costa <glommer@openvz.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

super: fix calculation of shrinkable objects for small numbers

The sysctl knob sysctl_vfs_cache_pressure is used to determine which
percentage of the shrinkable objects in our cache we should actively try
to shrink.

It works great in situations in which we have many objects (at least more
than 100), because the aproximation errors will be negligible. But if
this is not the case, specially when total_objects < 100, we may end up
concluding that we have no objects at all (total / 100 = 0, if total <
100).

This is certainly not the biggest killer in the world, but may matter in
very low kernel memory situations.

Signed-off-by: Glauber Costa <glommer@openvz.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

quota: provide interface for readding allocated space into reserved space

ext4 needs to convert allocated (metadata) blocks back into blocks
reserved for delayed allocation. Add functions into quota code for
supporting such operation.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

quota: Convert use of typedef ctl_table to struct ctl_table

This typedef is unnecessary and should just be removed.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: add missing use of dq_data_lock in __dquot_initialize

The bulk of __dquot_initialize runs under the dqptr_sem which
protects the inode->i_dquot pointers. It doesn't protect the
dereferenced contents, though. Those are protected by the
dq_data_lock, which is missing around the dquot_resv_space call.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Silence warning about PRJQUOTA not being handled in need_print_warning()

PRJQUOTA value of quota type should never reach need_print_warning() since XFS
(which is the only fs which uses that type) doesn't use generic functions
calling this function. Anyway, add PRJQUOTA case to the switch to make gcc
happy.

Signed-off-by: Jan Kara <jack@suse.cz>

userns: Convert quota

Now that the type changes are done, here is the final set of
changes to make the quota code work when user namespaces are enabled.

Small cleanups and fixes to make the code build when user namespaces
are enabled.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

userns: Convert struct dquot_warn

Convert w_dq_id to be a struct kquid and remove the now unncessary
w_dq_type.

This is a simple conversion and enough other places have already
been converted that this actually reduces the code complexity
by a little bit, when removing now unnecessary type conversions.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

userns: Convert struct dquot dq_id to be a struct kqid

Change struct dquot dq_id to a struct kqid and remove the now
unecessary dq_type.

Make minimal changes to dquot, quota_tree, quota_v1, quota_v2, ext3,
ext4, and ocfs2 to deal with the change in quota structures and
signatures. The ocfs2 changes are larger than most because of the
extensive tracing throughout the ocfs2 quota code that prints out
dq_id.

quota_tree.c:get_index is modified to take a struct kqid instead of a
qid_t because all of it's callers pass in dquot->dq_id and it allows
me to introduce only a single conversion.

The rest of the changes are either just replacing dq_type with dq_id.type,
adding conversions to deal with the change in type and occassionally
adding qid_eq to allow quota id comparisons in a user namespace safe way.

Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Theodore Tso <tytso@mit.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

userns: Modify dqget to take struct kqid

Modify dqget to take struct kqid instead of a type and an identifier
pair.

Modify the callers of dqget in ocfs2 and dquot to take generate
a struct kqid so they can continue to call dqget. The conversion
to create struct kqid should all be the final conversions that
are needed in those code paths.

Cc: Jan Kara <jack@suse.cz>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

userns: Convert quota netlink aka quota_send_warning

Modify quota_send_warning to take struct kqid instead a type and
identifier pair.

When sending netlink broadcasts always convert uids and quota
identifiers into the intial user namespace. There is as yet no way to
send a netlink broadcast message with different contents to receivers
in different namespaces, so for the time being just map all of the
identifiers into the initial user namespace which preserves the
current behavior.

Change the callers of quota_send_warning in gfs2, xfs and dquot
to generate a struct kqid to pass to quota send warning. When
all of the user namespaces convesions are complete a struct kqid
values will be availbe without need for conversion, but a conversion
is needed now to avoid needing to convert everything at once.

Cc: Ben Myers <bpm@sgi.com>
Cc: Alex Elder <elder@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

userns: Convert qutoactl

Update the quotactl user space interface to successfull compile with
user namespaces support enabled and to hand off quota identifiers to
lower layers of the kernel in struct kqid instead of type and qid
pairs.

The quota on function is not converted because while it takes a quota
type and an id. The id is the on disk quota format to use, which
is something completely different.

The signature of two struct quotactl_ops methods were changed to take
struct kqid argumetns get_dqblk and set_dqblk.

The dquot, xfs, and ocfs2 implementations of get_dqblk and set_dqblk
are minimally changed so that the code continues to work with
the change in parameter type.

This is the first in a series of changes to always store quota
identifiers in the kernel in struct kqid and only use raw type and qid
values when interacting with on disk structures or userspace. Always
using struct kqid internally makes it hard to miss places that need
conversion to or from the kernel internal values.

Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: Alex Elder <elder@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

quota: Move down dqptr_sem read after initializing default warn[] type at __dquot_alloc_space().

sb->s_dqopt->dqptr_sem is used to serialize ops using pointers from inode to
dquots. But for __dquot_alloc_space(), it could be safely moved down after the
default warn[] array got initialized.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Split dquot_quota_sync() to writeback and cache flushing part

Split off part of dquot_quota_sync() which writes dquots into a quota file
to a separate function. In the next patch we will use the function from
filesystems and we do not want to abuse ->quota_sync quotactl callback more
than necessary.

Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

quota: fix checkpatch.pl warning by replacing <asm/uaccess.h> with <linux/uaccess.h>

checkpatch.pl warns:

"WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>"

Below patch fixes it.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Get rid of nested I_MUTEX_QUOTA locking subclass

So far i_mutex was ranking above dqonoff_mutex and i_mutex on quota files
was special and ranking below dqonoff_mutex (and several other locks).
However there's no real need for i_mutex on quota files to be special.
IO on quota files is serialized by dqio_mutex anyway so we don't need to
take i_mutex when writing to quota files. Other places where we take i_mutex
on quota file can accomodate standard i_mutex lock ranking, we only need
to change the lock ranking to be dqonoff_mutex > i_mutex which is a matter
of changing documentation because there's no place which would enforce
ordering in the other direction.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Use precomputed value of sb_dqopt in dquot_quota_sync

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix double lock in add_dquot_ref() with CONFIG_QUOTA_DEBUG

When CONFIG_QUOTA_DEBUG is enabled we call inode_get_rsv_space() from
add_dquot_ref() while holding i_lock. But inode_get_rsv_space() is trying
to get i_lock as well resulting in double lock.

Fix the problem by moving inode_get_rsv_space() call out of i_lock.

Reported-and-analyzed-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Make quota code not call tty layer with dqptr_sem held

dqptr_sem can be called from slab reclaim. tty layer uses GFP_KERNEL mask for
allocation so it can end up calling slab reclaim. Given quota code can call
into tty layer to print warning this creates possibility for lock inversion
between tty->atomic_write_lock and dqptr_sem.

Using direct printing of warnings from quota layer is obsolete but since it's
easy enough to change quota code to not hold any locks when printing warnings,
let's just do it. It seems like a good thing to do even when we use netlink
layer to transmit warnings to userspace.

Reported-by: Markus <M4rkusXXL@web.de>
Signed-off-by: Jan Kara <jack@suse.cz>

security: trim security.h

Trim security.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>

quota: Pass information that quota is stored in system file to userspace

Quota tools need to know whether quota is stored in a system file or in
classical aquota.{user|group} files. So pass this information as a flag
in GETINFO quotactl.

Signed-off-by: Jan Kara <jack@suse.cz>

vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs: move code out of buffer.c

Move invalidate_bdev, block_sync_page into fs/block_dev.c. Export
kill_bdev as well, so brd doesn't have to open code it. Reduce
buffer_head.h requirement accordingly.

Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving. The small comment replacing it says enough.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

vmscan: change shrinker API by passing shrink_control struct

Change each shrinker's API by consolidating the existing parameters into
shrink_control struct. This will simplify any further features added w/o
touching each file of shrinker.

[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: fix warning]
[kosaki.motohiro@jp.fujitsu.com: fix up new shrinker API]
[akpm@linux-foundation.org: fix xfs warning]
[akpm@linux-foundation.org: update gfs2]
Signed-off-by: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

quota: Don't write quota info in dquot_commit()

There's no reason to write quota info in dquot_commit(). The writing is a
relict from the old days when we didn't have dquot_acquire() and
dquot_release() and thus dquot_commit() could have created / removed quota
structures from the file. These days dquot_commit() only updates usage counters
/ limits in quota structure and thus there's no need to write quota info.

This also fixes an issue with journaling filesystem which didn't reserve
enough space in the transaction for write of quota info (it could have been
dirty at the time of dquot_commit() because of a race with other operation
changing it).

CC: stable@kernel.org
Reported-and-tested-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

fs: move i_sb_list out from under inode_lock

Protect the per-sb inode list with a new global lock
inode_sb_list_lock and use it to protect the list manipulations and
traversals. This lock replaces the inode_lock as the inodes on the
list can be validity checked while holding the inode->i_lock and
hence the inode_lock is no longer needed to protect the list.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs: protect inode->i_state with inode->i_lock

Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.

This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.

Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

quota: Fix deadlock during path resolution

As Al Viro pointed out path resolution during Q_QUOTAON calls to quotactl
is prone to deadlocks. We hold s_umount semaphore for reading during the
path resolution and resolution itself may need to acquire the semaphore
for writing when e. g. autofs mountpoint is passed.

Solve the problem by performing the resolution before we get hold of the
superblock (and thus s_umount semaphore). The whole thing is complicated
by the fact that some filesystems (OCFS2) ignore the path argument. So to
distinguish between filesystem which want the path and which do not we
introduce new .quota_on_meta callback which does not get the path. OCFS2
then uses this callback instead of old .quota_on.

CC: Al Viro <viro@ZenIV.linux.org.uk>
CC: Christoph Hellwig <hch@lst.de>
CC: Ted Ts'o <tytso@mit.edu>
CC: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Use %pV and __attribute__((format (printf in __quota_error and fix fallout

Use %pV in __quota_error so a single printk can not be
interleaved with other logging messages.
Add __attribute__((format (printf, 3, 4))) so format
and arguments can be verified by compiler.
Make sure printk formats and arguments match.

Block # needed a pointer dereference.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix possible oops in __dquot_initialize()

When quotaon(8) races with __dquot_initialize() or dqget() fails because
of EIO, ENOSPC, or similar error, we could possibly dereference NULL pointer
in inode->i_dquot[cnt]. Add proper checking.

Reported-by: Dmitry Monakhov <dmonakhov@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix issuing of warnings from dquot_transfer

__dquot_transfer accidentally called flush_warnings for a wrong set of
dquots which could result in quota warnings being issued with a wrong
identification. Also when operation fails because of EDQUOT, there's no
need check for issuing information message about user getting below limits
(no transfer has actually happened).

Signed-off-by: Jan Kara <jack@suse.cz>

quota: fix dquot_disable vs dquot_transfer race v2

I've got following lockup:
dquot_disable dquot_transfer
->dqget()
sb_has_quota_active
dqopt->flags &= ~dquot_state_flag(f, cnt) atomic_inc(dq->dq_count)
->drop_dquot_ref(sb, cnt);
down_write(dqptr_sem)
inode->i_dquot[cnt] = NULL ->__dquot_transfer
invalidate_dquots(sb, cnt); down_write(&dqptr_sem)
->wait for dq_wait_unused inode->i_dquot = new_dquot
/* wait forever */ ^^^^New quota user^^^^^^

We cannot allow new references to dquots from inodes after drop_dquot_ref()
has removed them. We have to recheck quota state under dqptr_sem and before
assignment, as we do it in dquot_initialize().

Signed-off-by: Dmitry Monakhov <dmonakhov@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

simplify checks for I_CLEAR/I_FREEING

add I_CLEAR instead of replacing I_FREEING with it. I_CLEAR is
equivalent to I_FREEING for almost all code looking at either;
it's there to keep track of having called clear_inode() exactly
once per inode lifetime, at some point after having set I_FREEING.
I_CLEAR and I_FREEING never get set at the same time with the
current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR
instead of I_CLEAR without loss of information. As the result of
such change, checks become simpler and the amount of code that needs
to know about I_CLEAR shrinks a lot.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

quota: Use mark_inode_dirty_sync instead of mark_inode_dirty

Quota code never touches file data. It just modifies i_blocks + i_bytes
of inodes and inode flags of quota files. So use mark_inode_dirty_sync
instead of mark_inode_dirty.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Change quota error message to print out disk and function name

The current quota error message doesn't always print the disk name, so
it is hard to identify the "bad" disk when quota error happens.

This patch changes the standardized quota error message to print out disk name
and function name. It also uses a combination of cpp macro and inline function
to provide better type checking and to lower the text size of the message.

[Jan Kara: Export __quota_error]

Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: clean up quota active checks

The various quota operations check for any quota beeing active on
a superblock, and the inode not having the noquota flag.

Merge these two checks into a dquot_active check and move that
into dquot.c as that's the only place where it's needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Clean up the namespace in dqblk_xfs.h

Almost all identifiers use the FS_* namespace, so rename the missing few
XFS_* ones to FS_* as well. Without this some people might get upset
about having too many XFS names in generic code.

Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: check quota reservation on remove_dquot_ref

Reserved space must being claimed before remove_dquot_ref() for a
given inode. Filesystem is responsible for performing force blocks
allocation in case of dealloc in ->quota_off. Let's add sanity check
for that case. Do it similar to add_dquot_ref().

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

mm: add context argument to shrinker callback

The current shrinker implementation requires the registered callback
to have global state to work from. This makes it difficult to shrink
caches that are not global (e.g. per-filesystem caches). Pass the shrinker
structure to the callback so that users can embed the shrinker structure
in the context the shrinker needs to operate on and get back to it in the
callback via container_of().

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

quota: Convert quota statistics to generic percpu_counter

Generic per-cpu counter has some memory overhead but it is negligible for
modern systems and embedded systems compile without quota support. And code
reuse is a good thing. This patch should fix complain from preemptive kernels
which was introduced by dde9588853b1bde.

[Jan Kara: Fixed patch to work on 32-bit archs as well]

Reported-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fixup dquot_transfer

Commit bc8e5f07392f05c47c8bdeff4f7098db440d065c had a typo which caused
quota miscomputation when changing owner group of a file. Linus will hate
me.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: rename default quotactl methods to dquot_

Follow the dquot_* style used elsewhere in dquot.c.

[Jan Kara: Fixed up missing conversion of ext2]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: explicitly set ->dq_op and ->s_qcop

Only set the quota operation vectors if the filesystem actually supports
quota instead of doing it for all filesystems in alloc_super().

[Jan Kara: Export dquot_operations and vfs_quotactl_ops]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: drop remount argument to ->quota_on and ->quota_off

Remount handling has fully moved into the filesystem, so all this is
superflous now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: kill the vfs_dq_off and vfs_dq_quota_on_remount wrappers

Instead of having wrappers in the VFS namespace export the dquot_suspend
and dquot_resume helpers directly. Also rename vfs_quota_disable to
dquot_disable while we're at it.

[Jan Kara: Moved dquot_suspend to quotaops.h and made it inline]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Refactor dquot_transfer code so that OCFS2 can pass in its references

Currently, __dquot_transfer() acquires its own references of dquot structures
that will be put into inode. But for OCFS2, this creates a lock inversion
between dq_lock (waited on in dqget) and transaction start (started in
ocfs2_setattr). Currently, deadlock is impossible because dq_lock is acquired
only during dquot_acquire and dquot_release and we already hold a reference to
dquot structures in ocfs2_setattr so neither of these functions can be called
while we call dquot_transfer. But this is rather subtle and it is hard to teach
lockdep about it. So provide __dquot_transfer function that can be passed dquot
references directly. OCFS2 can then pass acquired dquot references directly to
__dquot_transfer with proper locking.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: unify quota init condition in setattr

Quota must being initialized if size or uid/git changes requested.
But initialization performed in two different places:
in case of i_size file system is responsible for dquot init
, but in case of uid/gid init will be called internally in
dquot_transfer().
This ambiguity makes code harder to understand.
Let's move this logic to one common helper function.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: unify ->set_dqblk

Pass the larger struct fs_disk_quota to the ->set_dqblk operation so
that the Q_SETQUOTA and Q_XSETQUOTA operations can be implemented
with a single filesystem operation and we can retire the ->set_xquota
operation. The additional information (RT-subvolume accounting and
warn counts) are left zero for the VFS quota implementation.

Add new fieldmask values for setting the numer of blocks and inodes
values which is required for the VFS quota, but wasn't for XFS.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: unify ->get_dqblk

Pass the larger struct fs_disk_quota to the ->get_dqblk operation so
that the Q_GETQUOTA and Q_XGETQUOTA operations can be implemented
with a single filesystem operation and we can retire the ->get_xquota
operation. The additional information (RT-subvolume accounting and
warn counts) are left zero for the VFS quota implementation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Make quota stat accounting lockless.

Quota stats is mostly writable data structure. Let's alloc percpu
bucket for each value.

NOTE: dqstats_read() function is racy against dqstats_{inc,dec}
and may return inconsistent value. But this is ok since absolute
accuracy is not required.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

suppress warning: "quotatypes" defined but not used

Suppress compilation warning: "quotatypes" defined but not used.
quotatypes is used only when CONFIG_QUOTA_DEBUG or CONFIG_PRINT_QUOTA_WARNING
is/are defined.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: optimize mark_dirty logic

- Skip locking if quota is dirty already.
- Return old quota state to help fs-specciffic implementation to optimize
case where quota was dirty already.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: add the option to not fail with EDQUOT in block

To simplify metadata tracking for delalloc writes, ext4
will simply claim metadata blocks at allocation time, without
first speculatively reserving the worst case and then freeing
what was not used.

To do this, we need a mechanism to track allocations in
the quota subsystem, but potentially allow that allocation
to actually go over quota.

This patch adds a DQUOT_SPACE_NOFAIL flag and function
variants for this purpose.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

quota: use flags interface for dquot alloc/free space

Switch __dquot_alloc_space and __dquot_free_space to take flags
to indicate whether to warn and/or to reserve (or free reserve).

This is slightly more readable at the callpoints, and makes it
cleaner to add a "nofail" option in the next patch.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

quota: Convert __DQUOT_PARANOIA symbol to standard config option

Make __DQUOT_PARANOIA define from the old days a standard config option
and turn it off by default.

This gets rid of a quota warning about writes before quota is turned on
for systems with ext4 root filesystem. Currently there's no way to legally
solve this because /etc/mtab has to be written before quota is turned on
on most systems.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix possible dq_flags corruption

dq_flags are modified non-atomically in do_set_dqblk via __set_bit calls and
atomically for example in mark_dquot_dirty or clear_dquot_dirty. Hence a
change done by an atomic operation can be overwritten by a change done by a
non-atomic one. Fix the problem by using atomic bitops even in do_set_dqblk.

Signed-off-by: Andrew Perepechko <andrew.perepechko@sun.com>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Hide warnings about writes to the filesystem before quota was turned on

For a root filesystem write to the filesystem before quota is turned on happens
regularly and there's no way around it because of writes to syslog, /etc/mtab,
and similar. So the warning is rather pointless for ordinary users. It's
still useful during development so we just hide the warning behind
__DQUOT_PARANOIA config option.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: stop using QUOTA_OK / NO_QUOTA

Just use 0 / -EDQUOT directly - that's what it translates to anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

dquot: cleanup dquot initialize routine

Get rid of the initialize dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_initialize helper to __dquot_initialize
and vfs_dq_init to dquot_initialize to have a consistent namespace.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

dquot: move dquot initialization responsibility into the filesystem

Currently various places in the VFS call vfs_dq_init directly. This means
we tie the quota code into the VFS. Get rid of that and make the
filesystem responsible for the initialization. For most metadata operations
this is a straight forward move into the methods, but for truncate and
open it's a bit more complicated.

For truncate we currently only call vfs_dq_init for the sys_truncate case
because open already takes care of it for ftruncate and open(O_TRUNC) - the
new code causes an additional vfs_dq_init for those which is harmless.

For open the initialization is moved from do_filp_open into the open method,
which means it happens slightly earlier now, and only for regular files.
The latter is fine because we don't need to initialize it for operations
on special files, and we already do it as part of the namespace operations
for directories.

Add a dquot_file_open helper that filesystems that support generic quotas
can use to fill in ->open.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

dquot: cleanup dquot drop routine

Get rid of the drop dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_drop helper to __dquot_drop
and vfs_dq_drop to dquot_drop to have a consistent namespace.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

dquot: cleanup dquot transfer routine

Get rid of the transfer dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_transfer helper to __dquot_transfer
and vfs_dq_transfer to dquot_transfer to have a consistent namespace,
and make the new dquot_transfer return a normal negative errno value
which all callers expect.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

dquot: cleanup inode allocation / freeing routines

Get rid of the alloc_inode and free_inode dquot operations - they are
always called from the filesystem and if a filesystem really needs
their own (which none currently does) it can just call into it's
own routine directly.

Also get rid of the vfs_dq_alloc/vfs_dq_free wrappers and always
call the lowlevel dquot_alloc_inode / dqout_free_inode routines
directly, which now lose the number argument which is always 1.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

dquot: cleanup space allocation / freeing routines

Get rid of the alloc_space, free_space, reserve_space, claim_space and
release_rsv dquot operations - they are always called from the filesystem
and if a filesystem really needs their own (which none currently does)
it can just call into it's own routine directly.

Move shared logic into the common __dquot_alloc_space,
dquot_claim_space_nodirty and __dquot_free_space low-level methods,
and rationalize the wrappers around it to move as much as possible
code into the common block for CONFIG_QUOTA vs not. Also rename
all these helpers to be named dquot_* instead of vfs_dq_*.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Properly invalidate caches even for filesystems with blocksize < pagesize

Sometimes invalidate_bdev() can fail to invalidate a part of block
device cache because of dirty data. If the filesystem has blocksize
smaller than page size, this can happen even for pages containing
quota files and thus kernel would operate on stale data. Fix the
issue by syncing the filesystem before invalidating the cache.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: generalize quota transfer interface

Current quota transfer interface support only uid/gid.
This patch extend interface in order to support various quotas types
The goal is accomplished without changes in most frequently used
vfs_dq_transfer() func.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: sb_quota state flags cleanup

- remove hardcoded USRQUOTA/GRPQUOTA flags
- convert int to bool for appropriate functions

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: move code from sync_quota_sb into vfs_quota_sync

Currenly sync_quota_sb does a lot of sync and truncate action that only
applies to "VFS" style quotas and is actively harmful for the sync
performance in XFS. Move it into vfs_quota_sync and add a wait parameter
to ->quota_sync to tell if we need it or not.

My audit of the GFS2 code says it's also not needed given the way GFS2
implements quotas, but I'd be happy if this can get a detailed review.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix warning when a delayed write happens before quota is enabled

If a delayed-allocation write happens before quota is enabled, the
kernel spits out a warning:
WARNING: at fs/quota/dquot.c:988 dquot_claim_space+0x77/0x112()

because the fact that user has some delayed allocation is not recorded
in quota structure.

Make dquot_initialize() update amount of reserved space for user if it sees
inode has some space reserved. Also make sure that reserved quota space does
not go negative and we warn about the filesystem bug just once.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: manage reserved space when quota is not active [v2]

Since we implemented generic reserved space management interface,
then it is possible to account reserved space even when quota
is not active (similar to i_blocks/i_bytes).

Without this patch following testcase result in massive comlain from
WARN_ON in dquot_claim_space()

TEST_CASE:
mount /dev/sdb /mnt -oquota
dd if=/dev/zero of=/mnt/test bs=1M count=1
quotaon /mnt
# fs_reserved_spave == 1Mb
# quota_reserved_space == 0, because quota was disabled
dd if=/dev/zero of=/mnt/test seek=1 bs=1M count=1
# fs_reserved_spave == 2Mb
# quota_reserved_space == 1Mb
sync # ->dquot_claim_space() -> WARN_ON

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Cleanup S_NOQUOTA handling

Cleanup handling of S_NOQUOTA inode flag and document it a bit. The flag
does not have to be set under dqptr_sem. Only functions modifying inode's
dquot pointers have to check the flag under dqptr_sem before going forward
with the modification. This way we are sure that we cannot add new dquot
pointers to the inode which is just becoming a quota file.

The good thing about this cleanup is that there are no more places in quota
code which enforce i_mutex vs. dqptr_sem lock ordering (in particular that
dqptr_sem -> i_mutex of quota file). This should silence some (false) lockdep
warnings with ext4 + quota and generally make life of some filesystems easier.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix dquot_transfer for filesystems different from ext4

Commit fd8fbfc1 modified the way we find amount of reserved space
belonging to an inode. The amount of reserved space is checked
from dquot_transfer and thus inode_reserved_space gets called
even for filesystems that don't provide get_reserved_space callback
which results in a BUG.

Fix the problem by checking get_reserved_space callback and return 0 if
the filesystem does not provide it.

CC: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Move duplicated code to separate functions

- for(..) { mark_dquot_dirty(); } -> mark_all_dquot_dirty()
- for(..) { dput(); } -> dqput_all()

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: decouple fs reserved space from quota reservation

Currently inode_reservation is managed by fs itself and this
reservation is transfered on dquot_transfer(). This means what
inode_reservation must always be in sync with
dquot->dq_dqb.dqb_rsvspace. Otherwise dquot_transfer() will result
in incorrect quota(WARN_ON in dquot_claim_reserved_space() will be
triggered)
This is not easy because of complex locking order issues
for example http://bugzilla.kernel.org/show_bug.cgi?id=14739

The patch introduce quota reservation field for each fs-inode
(fs specific inode is used in order to prevent bloating generic
vfs inode). This reservation is managed by quota code internally
similar to i_blocks/i_bytes and may not be always in sync with
internal fs reservation.

Also perform some code rearrangement:
- Unify dquot_reserve_space() and dquot_reserve_space()
- Unify dquot_release_reserved_space() and dquot_free_space()
- Also this patch add missing warning update to release_rsv()
dquot_release_reserved_space() must call flush_warnings() as
dquot_free_space() does.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix WARN_ON in lookup_one_len

We should hold i_mutex when looking up quota files for journaled quotas,
otherwise a WARN_ON in lookup_one_len triggers. The fact that we didn't
hold i_mutex previously probably could not lead to a real bug since the
filesystem is just being mounted / remounted read-write and thus the
root directory cannot change anyway but it's definitely cleaner with
i_mutex.

Reported-by: Bastien ROUCARIES <roucaries.bastien@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

VFS: Export dquot_send_warning

Sending a message to userspace in a generic format to warn
of events (e.g. quota exceeded) in the quota subsystem is
a generically useful feature. This patch makes some minor
changes to the send_message function from dquot.c renaming
it quota_send_message, moving it to quota.c and exporting it
for use by filesystems which do not use the dquot code.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

sysctl: Drop & in front of every proc_handler.

For consistency drop & in front of every proc_handler. Explicity
taking the address is unnecessary and it prevents optimizations
like stubbing the proc_handlers to NULL.

Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl fs: Remove dead binary sysctl support

Now that sys_sysctl is a generic wrapper around /proc/sys .ctl_name
and .strategy members of sysctl tables are dead code. Remove them.

Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

const: make struct super_block::s_qcop const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

const: make struct super_block::dq_op const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

quota: Silence lockdep on quota_on

Commit d01730d74d2b0155da50d44555001706294014f7 didn't completely fix
the problem since we still take dqio_mutex and i_mutex in the wrong
order. Move taking of i_mutex further down (luckily it's needed only
for updating inode flags) below where dqio_mutex is taken.

Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Jan Kara <jack@suse.cz>

quota: Fix possible deadlock during parallel quotaon and quotaoff

The following test script triggers a deadlock on ext2 filesystem:
while true; do quotaon /dev/hda >&/dev/null; usleep $RANDOM; done &
while true; do quotaoff /dev/hda >&/dev/null; usleep $RANDOM; done &

I found there is a potential deadlock between quotaon and quotaoff (or
quotasync). Basically, all of quotactl operations need to be protected by
dqonoff_mutex. vfs_quota_off and vfs_quota_sync also call sb->s_op->quota_write
that needs to grab the i_mutex of the quota file. But in vfs_quota_on_inode
(called from quotaon operation), the current code tries to grab the i_mutex of
the quota file first before getting quonoff_mutex.

Reverse the order in which we take locks in vfs_quota_on_inode().

Jan Kara: Changed changelog to be more readable, made lockdep happy with
I_MUTEX_QUOTA.

Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>

vfs: skip I_CLEAR state inodes

clear_inode() will switch inode state from I_FREEING to I_CLEAR, and do so
_outside_ of inode_lock. So any I_FREEING testing is incomplete without a
coupled testing of I_CLEAR.

So add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and
add_dquot_ref().

Masayoshi MIZUMA discovered the bug in drop_pagecache_sb() and Jan Kara
reminds fixing the other two cases.

Masayoshi MIZUMA has a nice panic flow:

=====================================================================
[process A] | [process B]
| |
| prune_icache() | drop_pagecache()
| spin_lock(&inode_lock) | drop_pagecache_sb()
| inode->i_state |= I_FREEING; | |
| spin_unlock(&inode_lock) | V
| | | spin_lock(&inode_lock)
| V | |
| dispose_list() | |
| list_del() | |
| clear_inode() | |
| inode->i_state = I_CLEAR | |
| | | V
| | | if (inode->i_state & (I_FREEING|I_WILL_FREE))
| | | continue; <==== NOT MATCH
| | |
| | | (DANGER from here on! Accessing disposing inode!)
| | |
| | | __iget()
| | | list_move() <===== PANIC on poisoned list !!
V V |
(time)
=====================================================================

Reported-by: Masayoshi MIZUMA <m.mizuma@jp.fujitsu.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

quota: Coding style fixes

Wrap long lines, remove assignments from conditions, rewrite two
overcomplicated for loops.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Remove superfluous inlines

Remove inlines of large functions to decrease code size (saved 1543
bytes).

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Remove NODQUOT macro

Remove this macro which is just a definition of NULL. Fix a few coding style
issues along the way.

Signed-off-by: Jan Kara <jack@suse.cz>

quota: Make global quota locks cacheline aligned

Andrew Morton has suggested that three global quota locks can end up in the
same cacheline which can result in bad cacheline ping-pong on SMP machines.
Make locks cacheline aligned so that we avoid this problem (thanks goes to
Andrew for the idea).

Signed-off-by: Jan Kara <jack@suse.cz>
CC: Andrew Morton <akpm@linux-foundation.org>

quota: Move quota files into separate directory

Quota subsystem has more and more files. It's time to create a dir for it.

Signed-off-by: Jan Kara <jack@suse.cz>