quotactl_cmd_write() is only ever invoked when BLOCK is configured. When
!CONFIG_BLOCK, the build warning below is displayed. Let's fix that.

fs/quota/quota.c:311:12: warning: ‘quotactl_cmd_write’ defined but not used [-Wunused-function]

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NJan Kara <jack@suse.cz>

getname() is intended to copy pathname strings from userspace into a
kernel buffer. The result is just a string in kernel space. It would
however be quite helpful to be able to attach some ancillary info to
the string.

For instance, we could attach some audit-related info to reduce the
amount of audit-related processing needed. When auditing is enabled,
we could also call getname() on the string more than once and not
need to recopy it from userspace.

This patchset converts the getname()/putname() interfaces to return
a struct instead of a string. For now, the struct just tracks the
string in kernel space and the original userland pointer for it.

Later, we'll add other information to the struct as it becomes
convenient.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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: N"Eric W. Biederman" <ebiederm@xmission.com>

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: NSteven Whitehouse <swhiteho@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

checkpatch.pl warns:

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

Below patch fixes it.
Signed-off-by: NJie Liu <jeff.liu@oracle.com>
Signed-off-by: NJan Kara <jack@suse.cz>

Now that XFS takes quota reservations into account there is no need to flush
anything before reporting quotas - in addition to beeing fully transactional
all quota information is also 100% coherent with the rest of the filesystem
now.
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

This script causes a kernel deadlock:
set -e
DEVICE=/dev/vg1/linear
lvchange -ay $DEVICE
mkfs.ext3 $DEVICE
mount -t ext3 -o usrquota,grpquota $DEVICE /mnt/test
quotacheck -gu /mnt/test
umount /mnt/test
mount -t ext3 -o usrquota,grpquota $DEVICE /mnt/test
quotaon /mnt/test
dmsetup suspend $DEVICE
setquota -u root 1 2 3 4 /mnt/test &
sleep 1
dmsetup resume $DEVICE

setquota acquired semaphore s_umount for read and then tried to perform a
transaction (and waits because the device is suspended).  dmsetup resume tries
to acquire s_umount for write before resuming the device (and waits for
setquota).

Fix the deadlock by grabbing a thawed superblock for quota commands which need
it.
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

One error exit from quotactl forgot to do path_put(). Fix that.
Reported-by: NValerie Aurora <val@vaaconsulting.com>
Signed-off-by: NJan Kara <jack@suse.cz>

This creates a new 'reason' field in a wb_writeback_work
structure, which unambiguously identifies who initiates
writeback activity.  A 'wb_reason' enumeration has been
added to writeback.h, to enumerate the possible reasons.

The 'writeback_work_class' and tracepoint event class and
'writeback_queue_io' tracepoints are updated to include the
symbolic 'reason' in all trace events.

And the 'writeback_inodes_sbXXX' family of routines has had
a wb_stats parameter added to them, so callers can specify
why writeback is being started.
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NCurt Wohlgemuth <curtw@google.com>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>

The concensus seems to be that system calls such as stat() etc should
not trigger an automount.  Neither should the l* versions.

This patch therefore adds a LOOKUP_AUTOMOUNT flag to tag those lookups
that _should_ trigger an automount on the last path element.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
[ Edited to leave out the cases that are already covered by LOOKUP_OPEN,
  LOOKUP_DIRECTORY and LOOKUP_CREATE - all of which also fundamentally
  force automounting for their own reasons   - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NJan Kara <jack@suse.cz>

Remount handling has fully moved into the filesystem, so all this is
superflous now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

... and switch the simple "loop over superblocks and do something"
loops to it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

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

We used to remove from s_list and s_instances at the same
time.  So let's *not* do the former and skip superblocks
that have empty s_instances in the loops over s_list.

The next step, of course, will be to get rid of rescan logics
in those loops.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The methods already do these checks, so remove them in the quotactl
implementation to allow non-VFS quota implementations to also support
these calls.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

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

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

Instead of adding ifdefs just split it into a new file.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Instead of adding ifdefs just split it into a new file.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Checking the "VFS" quota enabled and dirty bits from generic code means
this code will never get called for other implementations, e.g. XFS and
GFS2.  Grabbing the reference on the superblock really isn't much overhead
for a global Q_SYNC call, so just drop this optimization.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

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

Currently Q_XQUOTASYNC calls into the quota_sync method, but XFS does something
entirely different in it than the rest of the filesystems.  xfs_quota which
calls Q_XQUOTASYNC expects an asynchronous data writeout to flush delayed
allocations, while the "VFS" quota support wants to flush changes to the quota
file.

So make Q_XQUOTASYNC call into the writeback code directly and make the
quota_sync method optional as XFS doesn't need in the sense expected by the
rest of the quota code.

GFS2 was using limited XFS-style quota and has a quota_sync method fitting
neither the style used by vfs_quota_sync nor xfs_fs_quota_sync.  I left it
in for now as per discussion with Steve it expects to be called from the
sync path this way.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Stop having complicated different routines for checking permissions for
XQM vs "VFS" quotas.  Instead do the checks for having sb->s_qcop and
a valid type directly in do_quotactl, and munge the *quotactl_valid functions
into a check_quotactl_permission helper that only checks for permissions.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

The Q_SYNC command can be called without the path to a device, in which case
it iterates over all superblocks.  Special case this variant directly in
sys_quotactl so that the other code always gets a superblock and doesn't
need to deal with this case.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Move the checks for sb->s_qcop->foo next to the actual calls for them, same
for sb_has_quota_active checks where applicable.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Split out a helper for each non-trivial command from do_quotactl.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

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: NSteven Whitehouse <swhiteho@redhat.com>

Currently the VFS calls vfs_dq_sync to sync out disk quotas for a given
superblock.  This is a small wrapper around sync_dquots which for the
case of a non-NULL superblock is a small wrapper around quota_sync_sb.

Just make quota_sync_sb global (rename it to sync_quota_sb) and call it
directly.  Also call it directly for those cases in quota.c that have a
superblock and leave sync_dquots purely an iterator over sync_quota_sb and
remove it's superblock argument.

To make this nicer move the check for the lack of a quota_sync method
from the callers into sync_quota_sb.

[folded build fix from Alexander Beregalov <a.beregalov@gmail.com>]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Wrap long lines, remove assignments from conditions, rewrite two
overcomplicated for loops.
Signed-off-by: NJan Kara <jack@suse.cz>

Remove inlines of large functions to decrease code size (saved 1543
bytes).
Signed-off-by: NJan Kara <jack@suse.cz>

Quota subsystem has more and more files. It's time to create a dir for it.
Signed-off-by: NJan Kara <jack@suse.cz>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

If filesystem can handle quota files as system files hidden from users, we can
skip a lot of cache invalidation, syncing, inode flags setting etc. when
turning quotas on, off and quota_sync. Allow filesystem to indicate that it is
hiding quota files from users by DQUOT_QUOTA_SYS_FILE flag.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

Split DQUOT_USR_ENABLED (and DQUOT_GRP_ENABLED) into DQUOT_USR_USAGE_ENABLED
and DQUOT_USR_LIMITS_ENABLED. This way we are able to separately enable /
disable whether we should:
1) ignore quotas completely
2) just keep uptodate information about usage
3) actually enforce quota limits

This is going to be useful when quota is treated as filesystem metadata - we
then want to keep quota information uptodate all the time and just enable /
disable limits enforcement.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJames Morris <jmorris@namei.org>

Make loop in sync_dquots() checking whether there's something to write
more readable, remove useless variable and macro info_any_dirty() which
is used only in this place.
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: "Vegard Nossum" <vegard.nossum@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, we just turn quotas off on remount of filesystem to read-only
state.  The patch below adds necessary framework so that we can turn quotas
off on remount RO but we are able to automatically reenable them again when
filesystem is remounted to RW state.  All we need to do is to keep references
to inodes of quota files when remounting RO and using these references to
reenable quotas when remounting RW.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>