Use dax_is_supported() to validate whether the architecture has virtually aliased data caches at mount time. Mount fails 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.desnoy...@efficios.com> Cc: "Theodore Ts'o" <ty...@mit.edu> Cc: Andreas Dilger <adilger.ker...@dilger.ca> Cc: linux-e...@vger.kernel.org Cc: Andrew Morton <a...@linux-foundation.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: linux...@kvack.org Cc: linux-a...@vger.kernel.org Cc: Dan Williams <dan.j.willi...@intel.com> Cc: Vishal Verma <vishal.l.ve...@intel.com> Cc: Dave Jiang <dave.ji...@intel.com> Cc: Matthew Wilcox <wi...@infradead.org> Cc: Arnd Bergmann <a...@arndb.de> Cc: Russell King <li...@armlinux.org.uk> Cc: nvd...@lists.linux.dev Cc: linux-...@vger.kernel.org Cc: linux-fsde...@vger.kernel.org --- fs/ext4/super.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index c5fcf377ab1f..f2c11ae3ec29 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4743,7 +4743,10 @@ static int ext4_check_feature_compatibility(struct super_block *sb, } if (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) { - if (ext4_has_feature_inline_data(sb)) { + if (!dax_is_supported()) { + ext4_msg(sb, KERN_ERR, "DAX unsupported by architecture."); + return -EINVAL; + } else if (ext4_has_feature_inline_data(sb)) { ext4_msg(sb, KERN_ERR, "Cannot use DAX on a filesystem" " that may contain inline data"); return -EINVAL; -- 2.39.2