reiserfs: Protect reiserfs_quota_write() with write lock

commit 361d94a338a3fd0cee6a4ea32bbc427ba228e628 upstream.

Calls into reiserfs journalling code and reiserfs_get_block() need to
be protected with write lock. We remove write lock around calls to high
level quota code in the next patch so these paths would suddently become
unprotected.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index 72a0636..8169be9 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -2303,7 +2303,9 @@
 		tocopy = sb->s_blocksize - offset < towrite ?
 		    sb->s_blocksize - offset : towrite;
 		tmp_bh.b_state = 0;
+		reiserfs_write_lock(sb);
 		err = reiserfs_get_block(inode, blk, &tmp_bh, GET_BLOCK_CREATE);
+		reiserfs_write_unlock(sb);
 		if (err)
 			goto out;
 		if (offset || tocopy != sb->s_blocksize)
@@ -2319,10 +2321,12 @@
 		flush_dcache_page(bh->b_page);
 		set_buffer_uptodate(bh);
 		unlock_buffer(bh);
+		reiserfs_write_lock(sb);
 		reiserfs_prepare_for_journal(sb, bh, 1);
 		journal_mark_dirty(current->journal_info, sb, bh);
 		if (!journal_quota)
 			reiserfs_add_ordered_list(inode, bh);
+		reiserfs_write_unlock(sb);
 		brelse(bh);
 		offset = 0;
 		towrite -= tocopy;