Re: [PATCH v22 14/16] xfs: Add delattr mount option

Allison Henderson
2021-07-28T09:03:00Z

On 7/27/21 5:47 PM, Darrick J. Wong wrote:
> On Mon, Jul 26, 2021 at 11:20:51PM -0700, Allison Henderson wrote:
>> This patch adds a mount option to enable delayed attributes. Eventually
>> this can be removed when delayed attrs becomes permanent.
>>
>> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>> ---
>> fs/xfs/libxfs/xfs_attr.h | 2 +-
>> fs/xfs/xfs_mount.h | 1 +
>> fs/xfs/xfs_super.c | 11 ++++++++++-
>> fs/xfs/xfs_xattr.c | 2 ++
>> 4 files changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
>> index c0c92bd3..d4e7521 100644
>> --- a/fs/xfs/libxfs/xfs_attr.h
>> +++ b/fs/xfs/libxfs/xfs_attr.h
>> @@ -30,7 +30,7 @@ struct xfs_attr_list_context;
>>
>> static inline bool xfs_hasdelattr(struct xfs_mount *mp)
>> {
>> - return false;
>> + return mp->m_flags & XFS_MOUNT_DELATTR;
>> }
>>
>> /*
>> diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
>> index 66a47f5..2945868 100644
>> --- a/fs/xfs/xfs_mount.h
>> +++ b/fs/xfs/xfs_mount.h
>> @@ -257,6 +257,7 @@ typedef struct xfs_mount {
>> #define XFS_MOUNT_NOATTR2 (1ULL << 25) /* disable use of attr2 format */
>> #define XFS_MOUNT_DAX_ALWAYS (1ULL << 26)
>> #define XFS_MOUNT_DAX_NEVER (1ULL << 27)
>> +#define XFS_MOUNT_DELATTR (1ULL << 28) /* enable delayed attributes */
>
> So uh while we're renaming things away from "delattr", maybe this ...
>
> LOGGED ATTRIBUTE RE PLAY
>
> ... really should become the "larp" debug-only mount option.
>
> XFS_MOUNT_LARP
>
> Yeah. Do it!!!

Sure, though it sounds like Dave would prefer to see a debug option
instead of a mount option. Will name it larp though :-)

>
>> /*
>> * Max and min values for mount-option defined I/O
>> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
>> index 2c9e26a..39d6645 100644
>> --- a/fs/xfs/xfs_super.c
>> +++ b/fs/xfs/xfs_super.c
>> @@ -94,7 +94,7 @@ enum {
>> Opt_filestreams, Opt_quota, Opt_noquota, Opt_usrquota, Opt_grpquota,
>> Opt_prjquota, Opt_uquota, Opt_gquota, Opt_pquota,
>> Opt_uqnoenforce, Opt_gqnoenforce, Opt_pqnoenforce, Opt_qnoenforce,
>> - Opt_discard, Opt_nodiscard, Opt_dax, Opt_dax_enum,
>> + Opt_discard, Opt_nodiscard, Opt_dax, Opt_dax_enum, Opt_delattr
>> };
>>
>> static const struct fs_parameter_spec xfs_fs_parameters[] = {
>> @@ -139,6 +139,7 @@ static const struct fs_parameter_spec xfs_fs_parameters[] = {
>> fsparam_flag("nodiscard", Opt_nodiscard),
>> fsparam_flag("dax", Opt_dax),
>> fsparam_enum("dax", Opt_dax_enum, dax_param_enums),
>> + fsparam_flag("delattr", Opt_delattr),
>
> I think you need this line to be guarded by #ifdefs so that the mount
> options parsing code will reject -o larp on non-debug kernels.

Sure, though this may go away if we turn it into a debug option.

>
> --D
>
>> {}
>> };
>>
>> @@ -1273,6 +1274,14 @@ xfs_fs_parse_param(
>> xfs_mount_set_dax_mode(parsing_mp, result.uint_32);
>> return 0;
>> #endif
>> +#ifdef CONFIG_XFS_DEBUG
>> + case Opt_delattr:
>> + xfs_warn(parsing_mp,
>> + "EXPERIMENTAL logged xattrs feature in use. "
>> + "Use at your own risk");
>> + parsing_mp->m_flags |= XFS_MOUNT_DELATTR;
>> + return 0;
>> +#endif
>> /* Following mount options will be removed in September 2025 */
>> case Opt_ikeep:
>> xfs_fs_warn_deprecated(fc, param, XFS_MOUNT_IKEEP, true);
>> diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
>> index 0d050f8..a4f97e7 100644
>> --- a/fs/xfs/xfs_xattr.c
>> +++ b/fs/xfs/xfs_xattr.c
>> @@ -8,6 +8,8 @@
>> #include "xfs_shared.h"
>> #include "xfs_format.h"
>> #include "xfs_log_format.h"
>> +#include "xfs_trans_resv.h"
>> +#include "xfs_mount.h"
>> #include "xfs_da_format.h"
>> #include "xfs_trans_resv.h"
>> #include "xfs_mount.h"
>> --
>> 2.7.4
>>