diff mbox

ext2, ext4: warn when mounting with dax enabled

Message ID 20150929194806.5276.863.stgit@dwillia2-desk3.jf.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dan Williams Sept. 29, 2015, 7:48 p.m. UTC 
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@suse.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: linux-ext4@vger.kernel.org
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
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(-)


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Comments

Jan Kara Oct. 2, 2015, 2:16 p.m. UTC | #1 
On Tue 29-09-15 15:48:11, Dan Williams wrote:
> 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@suse.com>
> Cc: "Theodore Ts'o" <tytso@mit.edu>
> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
> Cc: Matthew Wilcox <willy@linux.intel.com>
> Cc: linux-ext4@vger.kernel.org
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Reported-by: Dave Chinner <david@fromorbit.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Agreed. You can add:
Acked-by: Jan Kara <jack@suse.com>

								Honza

> ---
> 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
> 
>
diff mbox

Patch

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