linux.git/fs/exofs, branch v4.6

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08+00:00

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 -  << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ;

 -  >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov 
Acked-by: Michal Hocko 
Signed-off-by: Linus Torvalds

wrappers for ->i_mutex access

2016-01-22T23:04:28+00:00

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro

kmemcg: account certain kmem allocations to memcg

2016-01-15T00:00:49+00:00

Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Vladimir Davydov 
Acked-by: Johannes Weiner 
Acked-by: Michal Hocko 
Cc: Tejun Heo 
Cc: Greg Thelen 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'work.symlinks' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-01-11T21:13:23+00:00

Pull vfs RCU symlink updates from Al Viro:
 "Replacement of ->follow_link/->put_link, allowing to stay in RCU mode
  even if the symlink is not an embedded one.

  No changes since the mailbomb on Jan 1"

* 'work.symlinks' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  switch ->get_link() to delayed_call, kill ->put_link()
  kill free_page_put_link()
  teach nfs_get_link() to work in RCU mode
  teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode
  teach shmem_get_link() to work in RCU mode
  teach page_get_link() to work in RCU mode
  replace ->follow_link() with new method that could stay in RCU mode
  don't put symlink bodies in pagecache into highmem
  namei: page_getlink() and page_follow_link_light() are the same thing
  ufs: get rid of ->setattr() for symlinks
  udf: don't duplicate page_symlink_inode_operations
  logfs: don't duplicate page_symlink_inode_operations
  switch befs long symlinks to page_symlink_operations

osd fs: __r4w_get_page rely on PageUptodate for uptodate

2015-12-12T18:15:34+00:00

Commit 42cb14b110a5 ("mm: migrate dirty page without
clear_page_dirty_for_io etc") simplified the migration of a PageDirty
pagecache page: one stat needs moving from zone to zone and that's about
all.

It's convenient and safest for it to shift the PageDirty bit from old
page to new, just before updating the zone stats: before copying data
and marking the new PageUptodate.  This is all done while both pages are
isolated and locked, just as before; and just as before, there's a
moment when the new page is visible in the radix_tree, but not yet
PageUptodate.  What's new is that it may now be briefly visible as
PageDirty before it is PageUptodate.

When I scoured the tree to see if this could cause a problem anywhere,
the only places I found were in two similar functions __r4w_get_page():
which look up a page with find_get_page() (not using page lock), then
claim it's uptodate if it's PageDirty or PageWriteback or PageUptodate.

I'm not sure whether that was right before, but now it might be wrong
(on rare occasions): only claim the page is uptodate if PageUptodate.
Or perhaps the page in question could never be migratable anyway?

Signed-off-by: Hugh Dickins 
Tested-by: Boaz Harrosh 
Cc: Benny Halevy 
Cc: Trond Myklebust 
Cc: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

don't put symlink bodies in pagecache into highmem

2015-12-09T03:41:36+00:00

kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.

new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases.  page_follow_link_light()
instrumented to yell about anything missed.

Signed-off-by: Al Viro

fs/exofs/namei.c: remove unnecessary new_valid_dev() check

2015-11-09T23:11:24+00:00

new_valid_dev() always returns 1, so the !new_valid_dev() check is not
needed.  Remove it.

Signed-off-by: Yaowei Bai 
Cc: Alexander Viro 
Acked-by: Boaz Harrosh 
Cc: Benny Halevy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pagemap.h: move dir_pages() over there

2015-06-23T22:02:00+00:00

That function was declared in a lot of filesystems to calculate
directory pages.

Signed-off-by: Fabian Frederick 
Signed-off-by: Al Viro

exofs: switch to {simple,page}_symlink_inode_operations

2015-05-11T02:18:27+00:00

ACK-by: Boaz Harrosh 
Signed-off-by: Al Viro

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