Similar to XFS warn when mounting DAX while it is still considered under development. Also, aspects of the DAX implementation, for example synchronization against multiple faults and faults causing block allocation, depend on the correct implementation in the filesystem. The maturity of a given DAX implementation is filesystem specific. Cc: Jan Kara <jack@xxxxxxxx> Cc: "Theodore Ts'o" <tytso@xxxxxxx> Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxxxx> Cc: linux-ext4@xxxxxxxxxxxxxxx Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reported-by: Dave Chinner <david@xxxxxxxxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> --- Given the pending investigations [1], and rather than marking FS_DAX broken, warn about DAX usage until we've landed fixes for the issues that Dave has identified. [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002266.html fs/ext2/super.c | 2 ++ fs/ext4/super.c | 6 +++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 900e19cf9ef6..2597b0663bf2 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -566,6 +566,8 @@ static int parse_options(char *options, struct super_block *sb) /* Fall through */ case Opt_dax: #ifdef CONFIG_FS_DAX + ext2_msg(sb, KERN_WARNING, + "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); set_opt(sbi->s_mount_opt, DAX); #else ext2_msg(sb, KERN_INFO, "dax option not supported"); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index a63c7b0a10cf..4db6eb0b6979 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1656,8 +1656,12 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, } sbi->s_jquota_fmt = m->mount_opt; #endif -#ifndef CONFIG_FS_DAX } else if (token == Opt_dax) { +#ifdef CONFIG_FS_DAX + ext4_msg(sb, KERN_WARNING, + "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); + sbi->s_mount_opt |= m->mount_opt; +#else ext4_msg(sb, KERN_INFO, "dax option not supported"); return -1; #endif -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
