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>
Honza
> ---
> fs/Kconfig | 1 +
> fs/dax.c | 2 --
> fs/ext2/Kconfig | 1 -
> 3 files changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 8e9e5f41..18024bf 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -38,6 +38,7 @@ config FS_DAX
> bool "Direct Access (DAX) support"
> depends on MMU
> depends on !(ARM || MIPS || SPARC)
> + select FS_IOMAP
> help
> Direct Access (DAX) can be used on memory-backed block devices.
> If the block device supports DAX and the filesystem supports DAX,
> diff --git a/fs/dax.c b/fs/dax.c
> index be39633..d8fe3eb 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -968,7 +968,6 @@ int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
> }
> EXPORT_SYMBOL_GPL(__dax_zero_page_range);
>
> -#ifdef CONFIG_FS_IOMAP
> static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos)
> {
> return iomap->blkno + (((pos & PAGE_MASK) - iomap->offset) >> 9);
> @@ -1405,4 +1404,3 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
> }
> EXPORT_SYMBOL_GPL(dax_iomap_pmd_fault);
> #endif /* CONFIG_FS_DAX_PMD */
> -#endif /* CONFIG_FS_IOMAP */
> diff --git a/fs/ext2/Kconfig b/fs/ext2/Kconfig
> index 36bea5a..c634874e 100644
> --- a/fs/ext2/Kconfig
> +++ b/fs/ext2/Kconfig
> @@ -1,6 +1,5 @@
> config EXT2_FS
> tristate "Second extended fs support"
> - select FS_IOMAP if FS_DAX
> help
> Ext2 is a standard Linux file system for hard disks.
>
> --
> 2.7.4
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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