writeback: fix occasional slow sync(1)

In case when system contains no dirty pages, wakeup_flusher_threads() will
submit WB_SYNC_NONE writeback for 0 pages so wb_writeback() exits
immediately without doing anything, even though there are dirty inodes in
the system.  Thus sync(1) will write all the dirty inodes from a
WB_SYNC_ALL writeback pass which is slow.

Fix the problem by using get_nr_dirty_pages() in wakeup_flusher_threads()
instead of calculating number of dirty pages manually.  That function also
takes number of dirty inodes into account.

Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Paul Taysom <taysom@chromium.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ext4: fix memory leak in xattr

If we take the 2nd retry path in ext4_expand_extra_isize_ea, we
potentionally return from the function without having freed these
allocations.  If we don't do the return, we over-write the previous
allocation pointers, so we leak either way.

Spotted with Coverity.

[ Fixed by tytso to set is and bs to NULL after freeing these
  pointers, in case in the retry loop we later end up triggering an
  error causing a jump to cleanup, at which point we could have a double
  free bug. -- Ted ]

Change-Id: I49b8ca41a6c6d44b563eb23306870258a3affd3b
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Cc: stable@vger.kernel.org
Git-commit: 6e4ea8e33b2057b85d75175dd89b93f5e26de3bc
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>
jfs: fix a couple races

commit 73aaa22d5ffb2630456bac2f9a4ed9b81d0d7271 upstream.

This patch fixes races uncovered by xfstests testcase 068.

One race is the result of jfs_sync() trying to write a sync point to the
journal after it has been frozen (or possibly in the process). Since
freezing sync's the journal, there is no need to write a sync point so
we simply want to return.

The second involves jfs_write_inode() being called on a deleted inode.
It calls jfs_flush_journal which is held up by the jfs_commit thread
doing the final iput on the same deleted inode, which itself is
waiting for the I_SYNC flag to be cleared. jfs_write_inode need not
do anything when i_nlink is zero, which is the easy fix.

Reported-by: Michael L. Semon <mlsemon35@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4: avoid bh leak in retry path of ext4_expand_extra_isize_ea()

commit dcb9917ba041866686fe152850364826c4622a36 upstream.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
jbd2: don't BUG but return ENOSPC if a handle runs out of space

commit f6c07cad081ba222d63623d913aafba5586c1d2c upstream.

If a handle runs out of space, we currently stop the kernel with a BUG
in jbd2_journal_dirty_metadata().  This makes it hard to figure out
what might be going on.  So return an error of ENOSPC, so we can let
the file system layer figure out what is going on, to make it more
likely we can get useful debugging information).  This should make it
easier to debug problems such as the one which was reported by:

    https://bugzilla.kernel.org/show_bug.cgi?id=44731

The only two callers of this function are ext4_handle_dirty_metadata()
and ocfs2_journal_dirty().  The ocfs2 function will trigger a
BUG_ON(), which means there will be no change in behavior.  The ext4
function will call ext4_error_inode() which will print the useful
debugging information and then handle the situation using ext4's error
handling mechanisms (i.e., which might mean halting the kernel or
remounting the file system read-only).

Also, since both file systems already call WARN_ON(), drop the WARN_ON
from jbd2_journal_dirty_metadata() to avoid two stack traces from
being displayed.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: ocfs2-devel@oss.oracle.com
Acked-by: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
jf: update 8064/jf board from MKG