hfs: add error checking for hfs_find_init()

hfs_find_init() may fail with ENOMEM, but there are places, where the
returned value is not checked.  The consequences can be very unpleasant,
e.g.  kfree uninitialized pointer and inappropriate mutex unlocking.

The patch adds checks for errors in hfs_find_init().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 3031dfd..0847471 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -416,9 +416,12 @@
 	struct inode *main_inode = inode;
 	struct hfs_find_data fd;
 	hfs_cat_rec rec;
+	int res;
 
 	dprint(DBG_INODE, "hfs_write_inode: %lu\n", inode->i_ino);
-	hfs_ext_write_extent(inode);
+	res = hfs_ext_write_extent(inode);
+	if (res)
+		return res;
 
 	if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 		switch (inode->i_ino) {
@@ -515,7 +518,11 @@
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 
-	hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
+	res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
+	if (res) {
+		iput(inode);
+		return ERR_PTR(res);
+	}
 	fd.search_key->cat = HFS_I(dir)->cat_key;
 	res = hfs_brec_read(&fd, &rec, sizeof(rec));
 	if (!res) {