f2fs: avoid RECLAIM_FS-ON-W warning

This patch should resolve the following possible bug.

RECLAIM_FS-ON-W at:
 mark_held_locks+0xb9/0x140
 lockdep_trace_alloc+0x85/0xf0
 __kmalloc+0x53/0x1d0
 read_all_xattrs+0x3d1/0x3f0 [f2fs]
 f2fs_getxattr+0x4f/0x100 [f2fs]
 f2fs_get_acl+0x4c/0x290 [f2fs]
 get_acl+0x4f/0x80
 posix_acl_create+0x72/0x180
 f2fs_init_acl+0x29/0xcc [f2fs]
 __f2fs_add_link+0x259/0x710 [f2fs]
 f2fs_create+0xad/0x1c0 [f2fs]
 vfs_create+0xed/0x150
 do_last+0xd36/0xed0
 path_openat+0xc5/0x680
 do_filp_open+0x43/0xa0
 do_sys_open+0x13c/0x230
 SyS_creat+0x1e/0x20
 system_call_fastpath+0x16/0x1b

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/acl.c

@@ -174,7 +174,7 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
 
 	retval = f2fs_getxattr(inode, name_index, "", NULL, 0);
 	if (retval > 0) {
-		value = kmalloc(retval, GFP_KERNEL);
+		value = kmalloc(retval, GFP_F2FS_ZERO);
 		if (!value)
 			return ERR_PTR(-ENOMEM);
 		retval = f2fs_getxattr(inode, name_index, "", value, retval);

fs/f2fs/xattr.c

@@ -275,7 +275,7 @@ static void *read_all_xattrs(struct inode *inode, struct page *ipage)
 
 	inline_size = inline_xattr_size(inode);
 
-	txattr_addr = kzalloc(inline_size + size, GFP_KERNEL);
+	txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
 	if (!txattr_addr)
 		return NULL;