litmus-rt.git/fs/kernfs, branch test

kernfs: Add support for always empty directories.

2015-07-21T17:10:00+00:00

commit ea015218f2f7ace2dad9cedd21ed95bdba2886d7 upstream.

Add a new function kernfs_create_empty_dir that can be used to create
directory that can not be modified.

Update the code to use make_empty_dir_inode when reporting a
permanently empty directory to the vfs.

Update the code to not allow adding to permanently empty directories.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Greg Kroah-Hartman

kernfs: do not account ino_ida allocations to memcg

2015-05-15T00:55:51+00:00

root->ino_ida is used for kernfs inode number allocations. Since IDA has
a layered structure, different IDs can reside on the same layer, which
is currently accounted to some memory cgroup. The problem is that each
kmem cache of a memory cgroup has its own directory on sysfs (under
/sys/fs/kernel//cgroup). If the inode number of such a
directory or any file in it gets allocated from a layer accounted to the
cgroup which the cache is created for, the cgroup will get pinned for
good, because one has to free all kmem allocations accounted to a cgroup
in order to release it and destroy all its kmem caches. That said we
must not account layers of ino_ida to any memory cgroup.

Since per net init operations may create new sysfs entries directly
(e.g. lo device) or indirectly (nf_conntrack creates a new kmem cache
per each namespace, which, in turn, creates new sysfs entries), an easy
way to reproduce this issue is by creating network namespace(s) from
inside a kmem-active memory cgroup.

Signed-off-by: Vladimir Davydov 
Acked-by: Tejun Heo 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Greg Thelen 
Cc: Greg Kroah-Hartman 
Cc: 	[4.0.x]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

VFS: normal filesystems (and lustre): d_inode() annotations

2015-04-15T19:06:57+00:00

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells 
Signed-off-by: Al Viro

kernfs: handle poll correctly on 'direct_read' files.

2015-03-16T20:51:20+00:00

Kernfs supports two styles of read: direct_read and seqfile_read.

The latter supports 'poll' correctly thanks to the update of
'->event' in kernfs_seq_show.
The former does not as '->event' is never updated on a read.

So add an appropriate update in kernfs_file_direct_read().

This was noticed because some 'md' sysfs attributes were
recently changed to use direct reads.

Reported-by: Prakash Punnoor 
Reported-by: Torsten Kaiser 
Fixes: 750f199ee8b578062341e6ddfe36c59ac8ff2dcb
Signed-off-by: NeilBrown 
Acked-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

kernfs: remove KERNFS_STATIC_NAME

2015-02-14T05:21:36+00:00

When a new kernfs node is created, KERNFS_STATIC_NAME is used to avoid
making a separate copy of its name.  It's currently only used for sysfs
attributes whose filenames are required to stay accessible and unchanged.
There are rare exceptions where these names are allocated and formatted
dynamically but for the vast majority of cases they're consts in the
rodata section.

Now that kernfs is converted to use kstrdup_const() and kfree_const(),
there's little point in keeping KERNFS_STATIC_NAME around.  Remove it.

Signed-off-by: Tejun Heo 
Cc: Andrzej Hajda 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernfs: convert node name allocation to kstrdup_const

2015-02-14T05:21:35+00:00

sysfs frequently performs duplication of strings located in read-only
memory section.  Replacing kstrdup by kstrdup_const allows to avoid such
operations.

Signed-off-by: Andrzej Hajda 
Cc: Marek Szyprowski 
Cc: Kyungmin Park 
Cc: Mike Turquette 
Cc: Alexander Viro 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Acked-by: Tejun Heo 
Cc: Greg KH 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs: remove mapping->backing_dev_info

2015-01-20T21:03:05+00:00

Now that we never use the backing_dev_info pointer in struct address_space
we can simply remove it and save 4 to 8 bytes in every inode.

Signed-off-by: Christoph Hellwig 
Acked-by: Ryusuke Konishi 
Reviewed-by: Tejun Heo 
Reviewed-by: Jan Kara 
Signed-off-by: Jens Axboe

fs: deduplicate noop_backing_dev_info

2015-01-20T21:02:54+00:00

hugetlbfs, kernfs and dlmfs can simply use noop_backing_dev_info instead
of creating a local duplicate.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

kernfs: Fix kernfs_name_compare

2015-01-09T23:51:08+00:00

Returning a difference from a comparison functions is usually wrong
(see acbbe6fbb240 "kcmp: fix standard comparison bug" for the long
story). Here there is the additional twist that if the void pointers
ns and kn->ns happen to differ by a multiple of 2^32,
kernfs_name_compare returns 0, falsely reporting a match to the
caller.

Technically 'hash - kn->hash' is ok since the hashes are restricted to
31 bits, but it's better to avoid that subtlety.

Signed-off-by: Rasmus Villemoes 
Acked-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

vm_area_operations: kill ->migrate()

2014-12-17T13:26:51+00:00

the only instance this method has ever grown was one in kernfs -
one that call ->migrate() of another vm_ops if it exists.

Signed-off-by: Al Viro