Re: [PATCH 02/10] xfs: allocate m_errortag early

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Jan 27, 2026 at 05:05:42PM +0100, Christoph Hellwig wrote:
> Ensure the mount structure always has a valid m_errortag for debug
> builds.  This removes the NULL checking from the runtime code, and
> prepares for allowing to set errortags from mount.

Hrmm.  Are you /sure/ you want to allow errortag mount options?
Saying that only because I really hate mount options.

> Signed-off-by: Christoph Hellwig <hch@lst.de>

Pre-failing the errortag array creation doesn't bother me that much
though, so
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_error.c | 26 +-------------------------
>  fs/xfs/xfs_super.c | 12 ++++++++++++
>  2 files changed, 13 insertions(+), 25 deletions(-)
> 
> diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
> index 873f2d1a134c..dfa4abf9fd1a 100644
> --- a/fs/xfs/xfs_error.c
> +++ b/fs/xfs/xfs_error.c
> @@ -114,18 +114,8 @@ int
>  xfs_errortag_init(
>  	struct xfs_mount	*mp)
>  {
> -	int ret;
> -
> -	mp->m_errortag = kzalloc(sizeof(unsigned int) * XFS_ERRTAG_MAX,
> -				GFP_KERNEL | __GFP_RETRY_MAYFAIL);
> -	if (!mp->m_errortag)
> -		return -ENOMEM;
> -
> -	ret = xfs_sysfs_init(&mp->m_errortag_kobj, &xfs_errortag_ktype,
> +	return xfs_sysfs_init(&mp->m_errortag_kobj, &xfs_errortag_ktype,
>  				&mp->m_kobj, "errortag");
> -	if (ret)
> -		kfree(mp->m_errortag);
> -	return ret;
>  }
>  
>  void
> @@ -133,7 +123,6 @@ xfs_errortag_del(
>  	struct xfs_mount	*mp)
>  {
>  	xfs_sysfs_del(&mp->m_errortag_kobj);
> -	kfree(mp->m_errortag);
>  }
>  
>  static bool
> @@ -154,8 +143,6 @@ xfs_errortag_enabled(
>  	struct xfs_mount	*mp,
>  	unsigned int		tag)
>  {
> -	if (!mp->m_errortag)
> -		return false;
>  	if (!xfs_errortag_valid(tag))
>  		return false;
>  
> @@ -171,17 +158,6 @@ xfs_errortag_test(
>  {
>  	unsigned int		randfactor;
>  
> -	/*
> -	 * To be able to use error injection anywhere, we need to ensure error
> -	 * injection mechanism is already initialized.
> -	 *
> -	 * Code paths like I/O completion can be called before the
> -	 * initialization is complete, but be able to inject errors in such
> -	 * places is still useful.
> -	 */
> -	if (!mp->m_errortag)
> -		return false;
> -
>  	if (!xfs_errortag_valid(error_tag))
>  		return false;
>  
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index e05bf62a5413..ee335dbe5811 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -40,6 +40,7 @@
>  #include "xfs_defer.h"
>  #include "xfs_attr_item.h"
>  #include "xfs_xattr.h"
> +#include "xfs_errortag.h"
>  #include "xfs_iunlink_item.h"
>  #include "xfs_dahash_test.h"
>  #include "xfs_rtbitmap.h"
> @@ -822,6 +823,9 @@ xfs_mount_free(
>  	debugfs_remove(mp->m_debugfs);
>  	kfree(mp->m_rtname);
>  	kfree(mp->m_logname);
> +#ifdef DEBUG
> +	kfree(mp->m_errortag);
> +#endif
>  	kfree(mp);
>  }
>  
> @@ -2254,6 +2258,14 @@ xfs_init_fs_context(
>  	mp = kzalloc(sizeof(struct xfs_mount), GFP_KERNEL);
>  	if (!mp)
>  		return -ENOMEM;
> +#ifdef DEBUG
> +	mp->m_errortag = kcalloc(XFS_ERRTAG_MAX, sizeof(*mp->m_errortag),
> +			GFP_KERNEL);
> +	if (!mp->m_errortag) {
> +		kfree(mp);
> +		return -ENOMEM;
> +	}
> +#endif
>  
>  	spin_lock_init(&mp->m_sb_lock);
>  	for (i = 0; i < XG_TYPE_MAX; i++)
> -- 
> 2.47.3
> 
>