linux-toradex.git/fs, branch v3.12.18

ext4: Speedup WB_SYNC_ALL pass called from sync(2)

2014-04-18T08:54:12+00:00

commit 10542c229a4e8e25b40357beea66abe9dacda2c0 upstream.

When doing filesystem wide sync, there's no need to force transaction
commit (or synchronously write inode buffer) separately for each inode
because ext4_sync_fs() takes care of forcing commit at the end (VFS
takes care of flushing buffer cache, respectively). Most of the time
this slowness doesn't manifest because previous WB_SYNC_NONE writeback
doesn't leave much to write but when there are processes aggressively
creating new files and several filesystems to sync, the sync slowness
can be noticeable. In the following test script sync(1) takes around 6
minutes when there are two ext4 filesystems mounted on a standard SATA
drive. After this patch sync takes a couple of seconds so we have about
two orders of magnitude improvement.

      function run_writers
      {
        for (( i = 0; i < 10; i++ )); do
          mkdir $1/dir$i
          for (( j = 0; j < 40000; j++ )); do
            dd if=/dev/zero of=$1/dir$i/$j bs=4k count=4 &>/dev/null
          done &
        done
      }

      for dir in "$@"; do
        run_writers $dir
      done

      sleep 40
      time sync

Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Jiri Slaby

NFSv3: Fix return value of nfs3_proc_setacls

2014-04-18T08:47:21+00:00

commit 8f493b9cfcd8941c6b27d6ce8e3b4a78c094b3c1 upstream.

nfs3_proc_setacls is used internally by the NFSv3 create operations
to set the acl after the file has been created. If the operation
fails because the server doesn't support acls, then it must return '0',
not -EOPNOTSUPP.

Reported-by: Russell King 
Link: http://lkml.kernel.org/r/20140201010328.GI15937@n2100.arm.linux.org.uk
Cc: Christoph Hellwig 
Tested-by: Takashi Iwai 
Signed-off-by: Trond Myklebust 
Acked-by: NeilBrown 
Signed-off-by: Jiri Slaby

nfs: initialize the ACL support bits to zero.

2014-04-18T08:46:14+00:00

commit a1800acaf7d1c2bf6d68b9a8f4ab8560cc66555a upstream.

Avoid returning incorrect acl mask attributes when the server doesn't
support ACLs.

Signed-off-by: Malahal Naineni 
Signed-off-by: Trond Myklebust 
Signed-off-by: Jiri Slaby

mm: close PageTail race

2014-04-03T08:32:30+00:00

commit 668f9abbd4334e6c29fa8acd71635c4f9101caa7 upstream.

Commit bf6bddf1924e ("mm: introduce compaction and migration for
ballooned pages") introduces page_count(page) into memory compaction
which dereferences page->first_page if PageTail(page).

This results in a very rare NULL pointer dereference on the
aforementioned page_count(page).  Indeed, anything that does
compound_head(), including page_count() is susceptible to racing with
prep_compound_page() and seeing a NULL or dangling page->first_page
pointer.

This patch uses Andrea's implementation of compound_trans_head() that
deals with such a race and makes it the default compound_head()
implementation.  This includes a read memory barrier that ensures that
if PageTail(head) is true that we return a head page that is neither
NULL nor dangling.  The patch then adds a store memory barrier to
prep_compound_page() to ensure page->first_page is set.

This is the safest way to ensure we see the head page that we are
expecting, PageTail(page) is already in the unlikely() path and the
memory barriers are unfortunately required.

Hugetlbfs is the exception, we don't enforce a store memory barrier
during init since no race is possible.

Signed-off-by: David Rientjes 
Cc: Holger Kiehl 
Cc: Christoph Lameter 
Cc: Rafael Aquini 
Cc: Vlastimil Babka 
Cc: Michal Hocko 
Cc: Mel Gorman 
Cc: Andrea Arcangeli 
Cc: Rik van Riel 
Cc: "Kirill A. Shutemov" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Jiri Slaby

make prepend_name() work correctly when called with negative *buflen

2014-04-03T08:32:29+00:00

commit e825196d48d2b89a6ec3a8eff280098d2a78207e upstream.

In all callchains leading to prepend_name(), the value left in *buflen
is eventually discarded unused if prepend_name() has returned a negative.
So we are free to do what prepend() does, and subtract from *buflen
*before* checking for underflow (which turns into checking the sign
of subtraction result, of course).

Signed-off-by: Al Viro 
Signed-off-by: Jiri Slaby

ext4: atomically set inode->i_flags in ext4_set_inode_flags()

2014-04-03T08:32:22+00:00

commit 00a1a053ebe5febcfc2ec498bd894f035ad2aa06 upstream.

Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time.

Reported-by: John Sullivan 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Linus Torvalds 
Signed-off-by: Jiri Slaby

FS-Cache: Handle removal of unadded object to the fscache_object_list rb tree

2014-04-03T08:32:20+00:00

commit 7026f1929e18921fd67bf478f475a8fdfdff16ae upstream.

When FS-Cache allocates an object, the following sequence of events can
occur:

 -->fscache_alloc_object()
    -->cachefiles_alloc_object() [via cache->ops->alloc_object]
    <--[returns new object]
    -->fscache_attach_object()
    <--[failed]
    -->cachefiles_put_object() [via cache->ops->put_object]
       -->fscache_object_destroy()
          -->fscache_objlist_remove()
             -->rb_erase() to remove the object from fscache_object_list.

resulting in a crash in the rbtree code.

The problem is that the object is only added to fscache_object_list on
the success path of fscache_attach_object() where it calls
fscache_objlist_add().

So if fscache_attach_object() fails, the object won't have been added to
the objlist rbtree.  We do, however, unconditionally try to remove the
object from the tree.

Thanks to NeilBrown for finding this and suggesting this solution.

Reported-by: NeilBrown 
Signed-off-by: David Howells 
Tested-by: (a customer of) NeilBrown 
Signed-off-by: Linus Torvalds 
Signed-off-by: Jiri Slaby

dlm: set zero linger time on sctp socket

2014-04-03T08:32:19+00:00

commit ece35848c1847cdf3dd07954578d3e99238ebbae upstream.

The recovery time for a failed node was taking a long
time because the failed node could not perform the full
shutdown process.  Removing the linger time speeds this
up.  The dlm does not care what happens to messages to
or from the failed node.

Signed-off-by: Dongmao Zhang 
Signed-off-by: David Teigland 
Signed-off-by: Jiri Slaby

NFSv4.1 free slot before resending I/O to MDS

2014-04-03T08:32:19+00:00

commit f9c96fcc501a43dbc292b17fc0ded4b54e63b79d upstream.

Fix a dynamic session slot leak where a slot is preallocated and I/O is
resent through the MDS.

Signed-off-by: Andy Adamson 
Signed-off-by: Trond Myklebust 
Signed-off-by: Jiri Slaby

nfs: add memory barriers around NFS_INO_INVALID_DATA and NFS_INO_INVALIDATING

2014-04-03T08:32:18+00:00

commit 4db72b40fdbc706f8957e9773ae73b1574b8c694 upstream.

If the setting of NFS_INO_INVALIDATING gets reordered to before the
clearing of NFS_INO_INVALID_DATA, then another task may hit a race
window where both appear to be clear, even though the inode's pages are
still in need of invalidation. Fix this by adding the appropriate memory
barriers.

Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust 
Signed-off-by: Jiri Slaby