On Tue 30-01-24 11:52:50, Mathieu Desnoyers wrote:
> Use dax_is_supported() to validate whether the architecture has
> virtually aliased data caches at mount time. Print an error and disable
> DAX if dax=always is requested as a mount option on an architecture
> which does not support DAX.
>
> This is relevant for architectures which require a dynamic check
> to validate whether they have virtually aliased data caches.
>
> Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxxx>
> Cc: linux-ext4@xxxxxxxxxxxxxxx
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-arch@xxxxxxxxxxxxxxx
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxx>
> Cc: nvdimm@xxxxxxxxxxxxxxx
> Cc: linux-cxl@xxxxxxxxxxxxxxx
> Cc: linux-fsdevel@xxxxxxxxxxxxxxx
OK, yeah, this is better than v1. Feel free to add:
Acked-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/ext2/super.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> index 01f9addc8b1f..30ff57d47ed4 100644
> --- a/fs/ext2/super.c
> +++ b/fs/ext2/super.c
> @@ -955,7 +955,11 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
> blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
>
> if (test_opt(sb, DAX)) {
> - if (!sbi->s_daxdev) {
> + if (!dax_is_supported()) {
> + ext2_msg(sb, KERN_ERR,
> + "DAX unsupported by architecture. Turning off DAX.");
> + clear_opt(sbi->s_mount_opt, DAX);
> + } else if (!sbi->s_daxdev) {
> ext2_msg(sb, KERN_ERR,
> "DAX unsupported by block device. Turning off DAX.");
> clear_opt(sbi->s_mount_opt, DAX);
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
