The event returned from fsnotify_add_notify_event() cannot ever be used
safely as the event may be freed by the time the function returns (after
dropping notification_mutex). So change the prototype to just return
whether the event was added or merged into some existing event.
Reported-and-tested-by: NJiri Kosina <jkosina@suse.cz>
Reported-and-tested-by: NDave Jones <davej@fedoraproject.org>
Signed-off-by: NJan Kara <jack@suse.cz>

After removing event structure creation from the generic layer there is
no reason for separate .should_send_event and .handle_event callbacks.
So just remove the first one.
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently fsnotify framework creates one event structure for each
notification event and links this event into all interested notification
groups.  This is done so that we save memory when several notification
groups are interested in the event.  However the need for event
structure shared between inotify & fanotify bloats the event structure
so the result is often higher memory consumption.

Another problem is that fsnotify framework keeps path references with
outstanding events so that fanotify can return open file descriptors
with its events.  This has the undesirable effect that filesystem cannot
be unmounted while there are outstanding events - a regression for
inotify compared to a situation before it was converted to fsnotify
framework.  For fanotify this problem is hard to avoid and users of
fanotify should kind of expect this behavior when they ask for file
descriptors from notified files.

This patch changes fsnotify and its users to create separate event
structure for each group.  This allows for much simpler code (~400 lines
removed by this patch) and also smaller event structures.  For example
on 64-bit system original struct fsnotify_event consumes 120 bytes, plus
additional space for file name, additional 24 bytes for second and each
subsequent group linking the event, and additional 32 bytes for each
inotify group for private data.  After the conversion inotify event
consumes 48 bytes plus space for file name which is considerably less
memory unless file names are long and there are several groups
interested in the events (both of which are uncommon).  Fanotify event
fits in 56 bytes after the conversion (fanotify doesn't care about file
names so its events don't have to have it allocated).  A win unless
there are four or more fanotify groups interested in the event.

The conversion also solves the problem with unmount when only inotify is
used as we don't have to grab path references for inotify events.

[hughd@google.com: fanotify: fix corruption preventing startup]
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: John McCutchan <john@johnmccutchan.com>
Cc: Robert Love <rlove@rlove.org>
Cc: Eric Paris <eparis@parisplace.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In fsnotify_destroy_mark() dont get the group from the passed mark anymore,
but pass the group itself as an additional parameter to the function.
Signed-off-by: NLino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: NEric Paris <eparis@redhat.com>

Get a group ref for each mark that is added to the groups list and release that
ref when the mark is freed in fsnotify_put_mark().
We also use get a group reference for duplicated marks and for private event
data.
Now we dont free a group any more when the number of marks becomes 0 but when
the groups ref count does. Since this will only happen when all marks are removed
from a groups mark list, we dont have to set the groups number of marks to 1 at
group creation.

Beside clearing all marks in fsnotify_destroy_group() we do also flush the
groups event queue. This is since events may hold references to groups (due to
private event data) and we have to put those references first before we get a
chance to put the final ref, which will result in a call to
fsnotify_final_destroy_group().
Signed-off-by: NLino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: NEric Paris <eparis@redhat.com>

On an error path in inotify_init1 a normal user can trigger a double
free of struct user.  This is a regression introduced by a2ae4cc9
("inotify: stop kernel memory leak on file creation failure").

We fix this by making sure that if a group exists the user reference is
dropped when the group is cleaned up.  We should not explictly drop the
reference on error and also drop the reference when the group is cleaned
up.

The new lifetime rules are that an inotify group lives from
inotify_new_group to the last fsnotify_put_group.  Since the struct user
and inotify_devs are directly tied to this lifetime they are only
changed/updated in those two locations.  We get rid of all special
casing of struct user or user->inotify_devs.
Signed-off-by: NEric Paris <eparis@redhat.com>
Cc: stable@kernel.org (2.6.37 and up)
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

This reverts commit 3bcf3860 (and the
accompanying commit c1e5c954 "vfs/fsnotify: fsnotify_close can delay
the final work in fput" that was a horribly ugly hack to make it work at
all).

The 'struct file' approach not only causes that disgusting hack, it
somehow breaks pulseaudio, probably due to some other subtlety with
f_count handling.

Fix up various conflicts due to later fsnotify work.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fanotify currently, when given a vfsmount_mark will look up (if it exists)
the corresponding inode mark.  This patch drops that lookup and uses the
mark provided.
Signed-off-by: NEric Paris <eparis@redhat.com>

should_send_event() and handle_event() will both need to look up the inode
event if they get a vfsmount event.  Lets just pass both at the same time
since we have them both after walking the lists in lockstep.
Signed-off-by: NEric Paris <eparis@redhat.com>

The change to use srcu and walk the object list rather than the global
fsnotify_group list means that should_send_event is no longer needed for a
number of groups and can be simplified for others.  Do that.
Signed-off-by: NEric Paris <eparis@redhat.com>

inotify now gets a mark in the should_send_event and handle_event
functions.  Rather than look up the mark themselves inotify should just use
the mark it was handed.
Signed-off-by: NEric Paris <eparis@redhat.com>

With the change of fsnotify to use srcu walking the marks list instead of
walking the global groups list we now know the mark in question.  The code can
send the mark to the group's handling functions and the groups won't have to
find those marks themselves.
Signed-off-by: NEric Paris <eparis@redhat.com>

Al explains that calling dentry_open() with a mnt/dentry pair is only
garunteed to be safe if they are already used in an open struct file.  To
make sure this is the case don't store and use a struct path in fsnotify,
always use a struct file.
Signed-off-by: NEric Paris <eparis@redhat.com>

Rather than the horrific void ** argument and such just to pass the
fanotify_merge event back to the caller of fsnotify_add_notify_event() have
those things return an event if it was different than the event suggusted to
be added.
Signed-off-by: NEric Paris <eparis@redhat.com>

It can be hard to debug fsnotify since there are so few printks.  Use
pr_debug to allow for dynamic debugging.
Signed-off-by: NEric Paris <eparis@redhat.com>

An inotify watch on a directory will send events for children even if those
children have been unlinked.  This patch add a new inotify flag IN_EXCL_UNLINK
which allows a watch to specificy they don't care about unlinked children.
This should fix performance problems seen by tasks which add a watch to
/tmp and then are overrun with events when other processes are reading and
writing to unlinked files they created in /tmp.

https://bugzilla.kernel.org/show_bug.cgi?id=16296Requested-by: NMatthias Clasen <mclasen@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

During the large inotify rewrite to fsnotify I completely dropped support
for IN_ONESHOT.  Reimplement that support.
Signed-off-by: NEric Paris <eparis@redhat.com>

Each group can define their own notification (and secondary_q) merge
function.  Inotify does tail drop, fanotify does matching and drop which
can actually allocate a completely new event.  But for fanotify to properly
deal with permissions events it needs to know the new event which was
ultimately added to the notification queue.  This patch just implements a
void ** argument which is passed to the merge function.  fanotify can use
this field to pass the new event back to higher layers.
Signed-off-by: NEric Paris <eparis@redhat.com>
for fanotify to properly deal with permissions events

currently all marking is done by functions in inode-mark.c.  Some of this
is pretty generic and should be instead done in a generic function and we
should only put the inode specific code in inode-mark.c
Signed-off-by: NEric Paris <eparis@redhat.com>

All callers to fsnotify_find_mark_entry() except one take and
release inode->i_lock around the call.  Take the lock inside
fsnotify_find_mark_entry() instead.
Signed-off-by: NAndreas Gruenbacher <agruen@suse.de>
Signed-off-by: NEric Paris <eparis@redhat.com>

rename anything in inotify that deals with mark_entry to just be mark.  It
makes a lot more sense.
Signed-off-by: NEric Paris <eparis@redhat.com>

the _entry portion of fsnotify functions is useless.  Drop it.
Signed-off-by: NEric Paris <eparis@redhat.com>

The name is long and it serves no real purpose.  So rename
fsnotify_mark_entry to just fsnotify_mark.
Signed-off-by: NEric Paris <eparis@redhat.com>

The addition of marks on vfs mounts will be simplified if the inode
specific parts of a mark and the vfsmnt specific parts of a mark are
actually in a union so naming can be easy.  This patch just implements the
inode struct and the union.
Signed-off-by: NEric Paris <eparis@redhat.com>

To ensure that a group will not duplicate events when it receives it based
on the vfsmount and the inode should_send_event test we should distinguish
those two cases.  We pass a vfsmount to this function so groups can make
their own determinations.
Signed-off-by: NEric Paris <eparis@redhat.com>

inotify only wishes to merge a new event with the last event on the
notification fifo.  fanotify is willing to merge any events including by
means of bitwise OR masks of multiple events together.  This patch moves
the inotify event merging logic out of the generic fsnotify notification.c
and into the inotify code.  This allows each use of fsnotify to provide
their own merge functionality.
Signed-off-by: NEric Paris <eparis@redhat.com>

fanotify is going to need to look at file->private_data to know if an event
should be sent or not.  This passes the data (which might be a file,
dentry, inode, or none) to the should_send function calls so fanotify can
get that information when available
Signed-off-by: NEric Paris <eparis@redhat.com>

fanotify is only interested in event types which contain enough information
to open the original file in the context of the fanotify listener.  Since
fanotify may not want to send events if that data isn't present we pass
the data type to the should_send_event function call so fanotify can express
its lack of interest.
Signed-off-by: NEric Paris <eparis@redhat.com>

inotify_new_group() receives a get_uid-ed user_struct and saves the
reference on group->inotify_data.user.  The problem is that free_uid() is
never called on it.

Issue seem to be introduced by 63c882a0 (inotify: reimplement inotify
using fsnotify) after 2.6.30.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Eric Paris <eparis@parisplace.org>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NEric Paris <eparis@redhat.com>

inotify will WARN() if it finds that the idr and the fsnotify internals
somehow got out of sync.  It was only supposed to do this once but due
to this stupid bug it would warn every single time a problem was
detected.
Signed-off-by: NEric Paris <eparis@redhat.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If an inotify watch is left in the idr when an fsnotify group is destroyed
this will lead to a BUG.  This is not a dangerous situation and really
indicates a programming bug and leak of memory.  This patch changes it to
use a WARN and a printk rather than killing people's boxes.
Signed-off-by: NEric Paris <eparis@redhat.com>

inotify decides if private data it passed to get added to an event was
used by checking list_empty().  But it's possible that the event may
have been dequeued and the private event removed so it would look empty.

The fix is to use the return code from fsnotify_add_notify_event rather
than looking at the list.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

inotify_destroy_mark_entry could get called twice for the same mark since it
is called directly in inotify_rm_watch and when the mark is being destroyed for
another reason.  As an example assume that the file being watched was just
deleted so inotify_destroy_mark_entry would get called from the path
fsnotify_inoderemove() -> fsnotify_destroy_marks_by_inode() ->
fsnotify_destroy_mark_entry() -> inotify_destroy_mark_entry().  If this
happened at the same time as userspace tried to remove a watch via
inotify_rm_watch we could attempt to remove the mark from the idr twice and
could thus double dec the ref cnt and potentially could be in a use after
free/double free situation.  The fix is to have inotify_rm_watch use the
generic recursive safe fsnotify_destroy_mark_by_entry() so we are sure the
inotify_destroy_mark_entry() function can only be called one.

This patch also renames the function to inotify_ingored_remove_idr() so it is
clear what is actually going on in the function.

Hopefully this fixes:
[   20.342058] idr_remove called for id=20 which is not allocated.
[   20.348000] Pid: 1860, comm: udevd Not tainted 2.6.30-tip #1077
[   20.353933] Call Trace:
[   20.356410]  [<ffffffff811a82b7>] idr_remove+0x115/0x18f
[   20.361737]  [<ffffffff8134259d>] ? _spin_lock+0x6d/0x75
[   20.367061]  [<ffffffff8111640a>] ? inotify_destroy_mark_entry+0xa3/0xcf
[   20.373771]  [<ffffffff8111641e>] inotify_destroy_mark_entry+0xb7/0xcf
[   20.380306]  [<ffffffff81115913>] inotify_freeing_mark+0xe/0x10
[   20.386238]  [<ffffffff8111410d>] fsnotify_destroy_mark_by_entry+0x143/0x170
[   20.393293]  [<ffffffff811163a3>] inotify_destroy_mark_entry+0x3c/0xcf
[   20.399829]  [<ffffffff811164d1>] sys_inotify_rm_watch+0x9b/0xc6
[   20.405850]  [<ffffffff8100bcdb>] system_call_fastpath+0x16/0x1b
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NEric Paris <eparis@redhat.com>
Tested-by: NPeter Ziljlstra <peterz@infradead.org>

inotify and dnotify will both indicate that they want any event which came
from a child inode.  The fix is to mask off FS_EVENT_ON_CHILD when deciding
if inotify or dnotify is interested in a given event.
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>