On Mon 28-11-16 12:15:04, Ross Zwisler wrote: > On Thu, Nov 24, 2016 at 10:02:39AM +0100, Jan Kara wrote: > > On Wed 23-11-16 11:44:17, Ross Zwisler wrote: > > > With the current Kconfig setup it is possible to have the following: > > > > > > CONFIG_EXT4_FS=y > > > CONFIG_FS_DAX=y > > > CONFIG_FS_IOMAP=n # this is in fs/Kconfig & isn't user accessible > > > > > > With this config we get build failures in ext4_dax_fault() because the > > > iomap functions in fs/dax.c are missing: > > > > > > fs/built-in.o: In function `ext4_dax_fault': > > > file.c:(.text+0x7f3ac): undefined reference to `dax_iomap_fault' > > > file.c:(.text+0x7f404): undefined reference to `dax_iomap_fault' > > > fs/built-in.o: In function `ext4_file_read_iter': > > > file.c:(.text+0x7fc54): undefined reference to `dax_iomap_rw' > > > fs/built-in.o: In function `ext4_file_write_iter': > > > file.c:(.text+0x7fe9a): undefined reference to `dax_iomap_rw' > > > file.c:(.text+0x7feed): undefined reference to `dax_iomap_rw' > > > fs/built-in.o: In function `ext4_block_zero_page_range': > > > inode.c:(.text+0x85c0d): undefined reference to `iomap_zero_range' > > > > > > Now that the struct buffer_head based DAX fault paths and I/O path have > > > been removed we really depend on iomap support being present for DAX. Make > > > this explicit by selecting FS_IOMAP if we compile in DAX support. > > > > > > Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> > > > > I've sent the same patch to Ted yesterday and he will probably queue it on > > top of ext4 iomap patches. If it doesn't happen for some reason, feel free > > to add: > > > > Reviewed-by: Jan Kara <jack@xxxxxxx> > > Cool, looks like Ted has pulled in your patch. > > I think we still eventually want this patch because it cleans up our handling > of FS_IOMAP. With your patch we select it separately in both ext4 & ext2 > based on whether we include DAX, and we still have #ifdefs in fs/dax.c for > FS_IOMAP. Actually, based on Dave's request I've also sent Ted updated version which did select FS_IOMAP in CONFIG_DAX section. However Ted didn't pull that patch (yet?). Anyway, I don't care whose patch gets merged, I just wanted to notify you of possible conflict. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>