This is a followup patch to the one implemeting rdesc representation in debugfs
rather than being dependent on compile-time CONFIG_HID_DEBUG setting.

The API of the appropriate formatting functions is slightly modified -- if
they are passed seq_file pointer, the one-shot output for 'rdesc' file mode
is used, and therefore the message is formatted into the corresponding seq_file
immediately.

Otherwise the called function allocated a new buffer, formats the text into the
buffer and returns the pointer to it, so that it can be queued into the ring-buffer
of the processess blocked waiting on input on 'events' file in debugfs.

'debug' parameter to the 'hid' module is now used solely for the prupose of inetrnal
driver state debugging (parser, transport, etc).
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

It is a little bit inconvenient for people who have some non-standard
HID hardware (usually violating the HID specification) to have to
recompile kernel with CONFIG_HID_DEBUG to be able to see kernel's perspective
of the HID report descriptor and observe the parsed events. Plus the messages
are then mixed up inconveniently with the rest of the dmesg stuff.

This patch implements /sys/kernel/debug/hid/<device>/rdesc file, which
represents the kernel's view of report descriptor (both the raw report
descriptor data and parsed contents).

With all the device-specific debug data being available through debugfs, there
is no need for keeping CONFIG_HID_DEBUG, as the 'debug' parameter to the
hid module will now only output only driver-specific debugging options, which has
absolutely minimal memory footprint, just a few error messages and one global
flag (hid_debug).

We use the current set of output formatting functions. The ones that need to be
used both for one-shot rdesc seq_file and also for continuous flow of data
(individual reports, as being sent by the device) distinguish according to the
passed seq_file parameter, and if it is NULL, it still output to kernel ringbuffer,
otherwise the corresponding seq_file is used for output.

The format of the output is preserved.
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

fs-internal parts of qnx4_fs.h taken to fs/qnx4/qnx4.h, includes adjusted,
qnx4_fs.h doesn't need unifdef anymore.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* have directory operations use mark_buffer_dirty_inode(),
  so that sync_mapping_buffers() would get those.
* make qnx4_write_inode() honour its last argument.
* get rid of insane copies of very ancient "walk the indirect blocks"
  in qnx4/fsync - they never matched the actual fs layout and, fortunately,
  never'd been called.  Again, all this junk is not needed; ->fsync()
  should just do sync_mapping_buffers + sync_inode (and if we implement
  block allocation for qnx4, we'll need to use mark_buffer_dirty_inode()
  for extent blocks)
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

writes associated buffers, then does sync_inode() to write
the inode itself (and to make it clean).  Depends on
->write_inode() honouring the second argument.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NMike Frysinger <vapier@gentoo.org>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The only user of the i_cindex element in the inode structure is used
is by the firewire drivers.  As part of an attempt to slim down the
inode structure to save memory --- since a typical Linux system will
have hundreds of thousands if not millions of inodes cached, a
reduction in the size inode has high leverage.

The firewire driver does not need i_cindex in any fast path, so it's
simple enough to calculate when it is needed, instead of wasting space
in the inode structure.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: krh@redhat.com
Cc: stefanr@s5r6.in-berlin.de
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

do_remount_sb() is fs/internal.h fodder, fsync_no_super() is long gone.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

d_unlinked() will be used in middle-term to ban checkpointing when opened
but unlinked file is detected, and in long term, to detect such situation
and special case on it.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Introduce this function which just writes all the quota structures but
avoids all the syncing and cache pruning work to expose quota structures
to userspace. Use this function from __sync_filesystem when wait == 0.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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>

Rename the function so that it better describe what it really does. Also
remove the unnecessary include of buffer_head.h.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Move sync_filesystems(), __fsync_super(), fsync_super() from
super.c to sync.c where it fits better.

[build fixes folded]
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It is unnecessarily fragile to have two places (fsync_super() and do_sync())
doing data integrity sync of the filesystem. Alter __fsync_super() to
accommodate needs of both callers and use it. So after this patch
__fsync_super() is the only place where we gather all the calls needed to
properly send all data on a filesystem to disk.

Nice bonus is that we get a complete livelock avoidance and write_supers()
is now only used for periodic writeback of superblocks.

sync_blockdevs() introduced a couple of patches ago is gone now.

[build fixes folded]
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

__fsync_super() does the same thing as fsync_super(). So change the only
caller to use fsync_super() and make __fsync_super() static. This removes
unnecessarily duplicated call to sync_blockdev() and prepares ground
for the changes to __fsync_super() in the following patches.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Remove the unused s_async_list in the superblock, a leftover of the
broken async inode deletion code that leaked into mainline.  Having this
in the middle of the sync/unmount path is not helpful for the following
cleanups.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch speeds up lmbench lat_mmap test by about another 2% after the
first patch.

Before:
 avg = 462.286
 std = 5.46106

After:
 avg = 453.12
 std = 9.58257

(50 runs of each, stddev gives a reasonable confidence)

It does this by introducing mnt_clone_write, which avoids some heavyweight
operations of mnt_want_write if called on a vfsmount which we know already
has a write count; and mnt_want_write_file, which can call mnt_clone_write
if the file is open for write.

After these two patches, mnt_want_write and mnt_drop_write go from 7% on
the profile down to 1.3% (including mnt_clone_write).

[AV: mnt_want_write_file() should take file alone and derive mnt from it;
not only all callers have that form, but that's the only mnt about which
we know that it's already held for write if file is opened for write]

Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch speeds up lmbench lat_mmap test by about 8%. lat_mmap is set up
basically to mmap a 64MB file on tmpfs, fault in its pages, then unmap it.
A microbenchmark yes, but it exercises some important paths in the mm.

Before:
 avg = 501.9
 std = 14.7773

After:
 avg = 462.286
 std = 5.46106

(50 runs of each, stddev gives a reasonable confidence, but there is quite
a bit of variation there still)

It does this by removing the complex per-cpu locking and counter-cache and
replaces it with a percpu counter in struct vfsmount. This makes the code
much simpler, and avoids spinlocks (although the msync is still pretty
costly, unfortunately). It results in about 900 bytes smaller code too. It
does increase the size of a vfsmount, however.

It should also give a speedup on large systems if CPUs are frequently operating
on different mounts (because the existing scheme has to operate on an atomic in
the struct vfsmount when switching between mounts). But I'm most interested in
the single threaded path performance for the moment.

[AV: minor cleanup]

Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NNick Piggin <npiggin@suse.de>
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>

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>

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

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

New field: nd->root.  When pathname resolution wants to know the root,
check if nd->root.mnt is non-NULL; use nd->root if it is, otherwise
copy current->fs->root there.  After path_walk() is finished, we check
if we'd got a cached value in nd->root and drop it.  Before calling
path_walk() we should either set nd->root.mnt to NULL *or* copy (and
pin down) some path to nd->root.  In the latter case we won't be
looking at current->fs->root at all.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch adds an -oexpose_privroot option to allow access to the privroot.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fsnotify tells its listeners explicitly when an event happened on the given
inode verses on the child of the given inode.  (see __fsnotify_parent)
However, the semantics of fsnotify_move() are such that we deliver events
directly to the two parent directories in question (old_dir and new_dir)
directly without using the __fsnotify_parent() call.  fsnotify should be
adding FS_EVENT_ON_CHILD for the notifications to these parents.
Signed-off-by: NEric Paris <eparis@redhat.com>

Reimplement inotify_user using fsnotify.  This should be feature for feature
exactly the same as the original inotify_user.  This does not make any changes
to the in kernel inotify feature used by audit.  Those patches (and the eventual
removal of in kernel inotify) will come after the new inotify_user proves to be
working correctly.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

When an fs is unmounted with an fsnotify mark entry attached to one of its
inodes we need to destroy that mark entry and we also (like inotify) send
an unmount event.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

inotify needs per group information attached to events.  This patch allows
groups to attach private information and implements a callback so that
information can be freed when an event is being destroyed.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

As part of the standard inotify events it includes a correlation cookie
between two dentry move operations.  This patch includes the same behaviour
in fsnotify events.  It is needed so that inotify userspace can be
implemented on top of fsnotify.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

When inotify wants to send events to a directory about a child it includes
the name of the original file.  This patch collects that filename and makes
it available for notification.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

inotify needs to do asyc notification in which event information is stored
on a queue until the listener is ready to receive it.  This patch
implements a generic notification queue for inotify (and later fanotify) to
store events to be sent at a later time.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

Reimplement dnotify using fsnotify.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

inotify and dnotify both use a similar parent notification mechanism.  We
add a generic parent notification mechanism to fsnotify for both of these
to use.  This new machanism also adds the dentry flag optimization which
exists for inotify to dnotify.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

This patch creates a way for fsnotify groups to attach marks to inodes.
These marks have little meaning to the generic fsnotify infrastructure
and thus their meaning should be interpreted by the group that attached
them to the inode's list.

dnotify and inotify  will make use of these markings to indicate which
inodes are of interest to their respective groups.  But this implementation
has the useful property that in the future other listeners could actually
use the marks for the exact opposite reason, aka to indicate which inodes
it had NO interest in.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

fsnotify is a backend for filesystem notification.  fsnotify does
not provide any userspace interface but does provide the basis
needed for other notification schemes such as dnotify.  fsnotify
can be extended to be the backend for inotify or the upcoming
fanotify.  fsnotify provides a mechanism for "groups" to register for
some set of filesystem events and to then deliver those events to
those groups for processing.

fsnotify has a number of benefits, the first being actually shrinking the size
of an inode.  Before fsnotify to support both dnotify and inotify an inode had

        unsigned long           i_dnotify_mask; /* Directory notify events */
        struct dnotify_struct   *i_dnotify; /* for directory notifications */
        struct list_head        inotify_watches; /* watches on this inode */
        struct mutex            inotify_mutex;  /* protects the watches list

But with fsnotify this same functionallity (and more) is done with just

        __u32                   i_fsnotify_mask; /* all events for this inode */
        struct hlist_head       i_fsnotify_mark_entries; /* marks on this inode */

That's right, inotify, dnotify, and fanotify all in 64 bits.  We used that
much space just in inotify_watches alone, before this patch set.

fsnotify object lifetime and locking is MUCH better than what we have today.
inotify locking is incredibly complex.  See 8f7b0ba1 as an example of
what's been busted since inception.  inotify needs to know internal semantics
of superblock destruction and unmounting to function.  The inode pinning and
vfs contortions are horrible.

no fsnotify implementers do allocation under locks.  This means things like
f04b30de which (due to an overabundance of caution) changes GFP_KERNEL to
GFP_NOFS can be reverted.  There are no longer any allocation rules when using
or implementing your own fsnotify listener.

fsnotify paves the way for fanotify.  In brief fanotify is a notification
mechanism that delivers the lisener both an 'event' and an open file descriptor
to the object in question.  This means that fanotify is pathname agnostic.
Some on lkml may not care for the original companies or users that pushed for
TALPA, but fanotify was designed with flexibility and input for other users in
mind.  The readahead group expressed interest in fanotify as it could be used
to profile disk access on boot without breaking the audit system.  The desktop
search groups have also expressed interest in fanotify as it solves a number
of the race conditions and problems present with managing inotify when more
than a limited number of specific files are of interest.  fanotify can provide
for a userspace access control system which makes it a clean interface for AV
vendors to hook without trying to do binary patching on the syscall table,
LSM, and everywhere else they do their things today.  With this patch series
fanotify can be implemented in less than 1200 lines of easy to review code.
Almost all of which is the socket based user interface.

This patch series builds fsnotify to the point that it can implement
dnotify and inotify_user.  Patches exist and will be sent soon after
acceptance to finish the in kernel inotify conversion (audit) and implement
fanotify.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

Now that we set up the slab allocator earlier, we can get rid of some
alloc_bootmem_cpumask_var() calls in boot code.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>