Race-free addition and removal of a mark to a groups mark list would be easier
if we could lock the mark list of group before we lock the specific mark.
This patch changes the order used to add/remove marks to/from mark lists from
1. mark->lock
2. group->mark_lock
3. inode->i_lock
to
1. group->mark_lock
2. mark->lock
3. inode->i_lock
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric 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: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
Removing the parent of a watched file results in "kernel BUG at
fs/notify/mark.c:139".
To reproduce
add "-w /tmp/audit/dir/watched_file" to audit.rules
rm -rf /tmp/audit/dir
This is caused by fsnotify_destroy_mark() being called without an
extra reference taken by the caller.
Reported by Francesco Cosoleto here:
https://bugzilla.novell.com/show_bug.cgi?id=689860
Fix by removing the BUG_ON and adding a comment about not accessing mark after
the iput.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>
Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All that remains of the inode_lock is protecting the inode hash list
manipulation and traversals. Rename the inode_lock to
inode_hash_lock to reflect it's actual function.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The global fsnotify groups lists were invented as a way to increase the
performance of fsnotify by shortcutting events which were not interesting.
With the changes to walk the object lists rather than global groups lists
these shortcuts are not useful.
Signed-off-by: Eric Paris <eparis@redhat.com>
Instead of moving list elements from destroy_list to &private_destroy_list,
exchange the list heads.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
Currently reading the inode->i_fsnotify_marks or
vfsmount->mnt_fsnotify_marks lists are protected by a spinlock on both the
read and the write side. This patch protects the read side of those lists
with a new single srcu.
Signed-off-by: Eric Paris <eparis@redhat.com>
Currently fsnotify check is mark->group is NULL to decide if
fsnotify_destroy_mark() has already been called or not. With the upcoming
rcu work it is a heck of a lot easier to use an explicit flag than worry
about group being set to NULL.
Signed-off-by: Eric Paris <eparis@redhat.com>
fsnotify takes an igrab on an inode when it adds a mark. The code was
supposed to drop the reference when the mark was removed but didn't.
This caused problems when an fs was unmounted because those inodes would
clearly not be gone. Thus resulting in the most devistating of messages:
VFS: Busy inodes after unmount of loop0. Self-destruct in 5 seconds.
>>> Have a nice day...
Jiri Slaby bisected the problem to a patch in the fsnotify tree. The
code snippets below show my stupidity quite clearly.
void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
{
...
mark->inode = NULL;
...
}
void fsnotify_destroy_mark(struct fsnotify_mark *mark)
{
struct inode *inode = NULL;
...
if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) {
fsnotify_destroy_inode_mark(mark);
inode = mark->i.inode;
}
...
if (inode)
iput(inode);
...
}
Obviously the intent was to capture the inode before it was set to NULL in
fsnotify_destory_inode_mark() so we wouldn't be leaking inodes forever.
Instead we leaked them (and exploded on umount)
Reported-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
fanotify listeners may want to clear all marks. They may want to do this
to destroy all of their inode marks which have nothing but ignores.
Realistically this is useful for av vendors who update policy and want to
clear all of their cached allows.
Signed-off-by: Eric Paris <eparis@redhat.com>
The ignored_mask is a new mask which is part of fsnotify marks. A group's
should_send_event() function can use the ignored mask to determine that
certain events are not of interest. In particular if a group registers a
mask including FS_OPEN on a vfsmount they could add FS_OPEN to the
ignored_mask for individual inodes and not send open events for those
inodes.
Signed-off-by: Eric Paris <eparis@redhat.com>
inotify marks must pin inodes in core. dnotify doesn't technically need to
since they are closed when the directory is closed. fanotify also need to
pin inodes in core as it works today. But the next step is to introduce
the concept of 'ignored masks' which is actually a mask of events for an
inode of no interest. I claim that these should be liberally sent to the
kernel and should not pin the inode in core. If the inode is brought back
in the listener will get an event it may have thought excluded, but this is
not a serious situation and one any listener should deal with.
This patch lays the ground work for non-pinning inode marks by using lazy
inode pinning. We do not pin a mark until it has a non-zero mask entry. If a
listener new sets a mask we never pin the inode.
Signed-off-by: Eric Paris <eparis@redhat.com>
Much like inode-mark.c has all of the code dealing with marks on inodes
this patch adds a vfsmount-mark.c which has similar code but is intended
for marks on vfsmounts.
Signed-off-by: Eric Paris <eparis@redhat.com>
Currently fsnotify_init_mark sets some fields to 0/NULL. Some users
already used some sorts of zalloc, some didn't. This patch uses memset to
explicitly zero everything in the fsnotify_mark when it is initialized so we
don't have to be careful if fields are later added to marks.
Signed-off-by: Eric Paris <eparis@redhat.com>
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: Eric Paris <eparis@redhat.com>
