reiserfs: don't preallocate blocks for extended attributes

BugLink: http://bugs.launchpad.net/bugs/1754592

commit 54930dfe upstream.

Most extended attributes will fit in a single block.  More importantly,
we drop the reference to the inode while holding the transaction open
so the preallocated blocks aren't released.  As a result, the inode
may be evicted before it's removed from the transaction's prealloc list
which can cause memory corruption.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

fs/reiserfs/bitmap.c

@@ -1136,7 +1136,7 @@ static int determine_prealloc_size(reiserfs_blocknr_hint_t * hint)
 	hint->prealloc_size = 0;
 
 	if (!hint->formatted_node && hint->preallocate) {
-		if (S_ISREG(hint->inode->i_mode)
+		if (S_ISREG(hint->inode->i_mode) && !IS_PRIVATE(hint->inode)
 		    && hint->inode->i_size >=
 		    REISERFS_SB(hint->th->t_super)->s_alloc_options.
 		    preallocmin * hint->inode->i_sb->s_blocksize)