I ran into a randconfig link error on next-20180228 that appears to have been caused by an older patch: fs/ext2/inode.o: In function `ext2_setattr': inode.c:(.text+0x19eb): undefined reference to `iomap_zero_range' This adds a compile-time conditional around the code path so the compiler can optimize out the reference in configurations that don't need it anyway. Fixes: 00697eed386d ("ext2: use iomap_zero_range() for zeroing truncated page in DAX path") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> --- fs/ext2/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 5d5e9f7b98d6..6e6db0ab3bd6 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -1296,7 +1296,7 @@ static int ext2_setsize(struct inode *inode, loff_t newsize) inode_dio_wait(inode); - if (IS_DAX(inode)) { + if (IS_ENABLED(CONFIG_FS_DAX) && IS_DAX(inode)) { error = iomap_zero_range(inode, newsize, PAGE_ALIGN(newsize) - newsize, NULL, &ext2_iomap_ops); -- 2.9.0