On Tue, Nov 19, 2024 at 02:30:52AM +0000, Catherine Hoang wrote:
> > On Nov 18, 2024, at 4:01 PM, Darrick J. Wong <djwong@xxxxxxxxxx> wrote:
> >
> > On Mon, Nov 18, 2024 at 03:52:55PM -0800, Catherine Hoang wrote:
> >> Add support for the new atomic_write_unit_min, atomic_write_unit_max, and
> >> atomic_write_segments_max fields in statx for xfs_io. In order to support builds
> >> against old kernel headers, define our own internal statx structs. If the
> >> system's struct statx does not have the required atomic write fields, override
> >> the struct definitions with the internal definitions in statx.h.
> >>
> >> Signed-off-by: Catherine Hoang <catherine.hoang@xxxxxxxxxx>
> >> ---
> >> configure.ac | 1 +
> >> include/builddefs.in | 4 ++++
> >> io/stat.c | 7 +++++++
> >> io/statx.h | 23 ++++++++++++++++++++++-
> >> m4/package_libcdev.m4 | 20 ++++++++++++++++++++
> >> 5 files changed, 54 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/configure.ac b/configure.ac
> >> index 33b01399..0b1ef3c3 100644
> >> --- a/configure.ac
> >> +++ b/configure.ac
> >> @@ -146,6 +146,7 @@ AC_HAVE_COPY_FILE_RANGE
> >> AC_NEED_INTERNAL_FSXATTR
> >> AC_NEED_INTERNAL_FSCRYPT_ADD_KEY_ARG
> >> AC_NEED_INTERNAL_FSCRYPT_POLICY_V2
> >> +AC_NEED_INTERNAL_STATX
> >> AC_HAVE_GETFSMAP
> >> AC_HAVE_MAP_SYNC
> >> AC_HAVE_DEVMAPPER
> >> diff --git a/include/builddefs.in b/include/builddefs.in
> >> index 1647d2cd..cbc9ab0c 100644
> >> --- a/include/builddefs.in
> >> +++ b/include/builddefs.in
> >> @@ -96,6 +96,7 @@ HAVE_COPY_FILE_RANGE = @have_copy_file_range@
> >> NEED_INTERNAL_FSXATTR = @need_internal_fsxattr@
> >> NEED_INTERNAL_FSCRYPT_ADD_KEY_ARG = @need_internal_fscrypt_add_key_arg@
> >> NEED_INTERNAL_FSCRYPT_POLICY_V2 = @need_internal_fscrypt_policy_v2@
> >> +NEED_INTERNAL_STATX = @need_internal_statx@
> >> HAVE_GETFSMAP = @have_getfsmap@
> >> HAVE_MAP_SYNC = @have_map_sync@
> >> HAVE_DEVMAPPER = @have_devmapper@
> >> @@ -130,6 +131,9 @@ endif
> >> ifeq ($(NEED_INTERNAL_FSCRYPT_POLICY_V2),yes)
> >> PCFLAGS+= -DOVERRIDE_SYSTEM_FSCRYPT_POLICY_V2
> >> endif
> >> +ifeq ($(NEED_INTERNAL_STATX),yes)
> >> +PCFLAGS+= -DOVERRIDE_SYSTEM_STATX
> >> +endif
> >> ifeq ($(HAVE_GETFSMAP),yes)
> >> PCFLAGS+= -DHAVE_GETFSMAP
> >> endif
> >> diff --git a/io/stat.c b/io/stat.c
> >> index 0f5618f6..7d1c1c93 100644
> >> --- a/io/stat.c
> >> +++ b/io/stat.c
> >> @@ -6,6 +6,10 @@
> >> * Portions of statx support written by David Howells (dhowells@xxxxxxxxxx)
> >> */
> >>
> >> +#ifdef OVERRIDE_SYSTEM_STATX
> >> +#define statx sys_statx
> >> +#endif
> >> +
> >> #include "command.h"
> >> #include "input.h"
> >> #include "init.h"
> >> @@ -347,6 +351,9 @@ dump_raw_statx(struct statx *stx)
> >> printf("stat.rdev_minor = %u\n", stx->stx_rdev_minor);
> >> printf("stat.dev_major = %u\n", stx->stx_dev_major);
> >> printf("stat.dev_minor = %u\n", stx->stx_dev_minor);
> >> + printf("stat.atomic_write_unit_min = %lld\n", (long long)stx->stx_atomic_write_unit_min);
> >> + printf("stat.atomic_write_unit_max = %lld\n", (long long)stx->stx_atomic_write_unit_max);
> >> + printf("stat.atomic_write_segments_max = %lld\n", (long long)stx->stx_atomic_write_segments_max);
> >> return 0;
> >> }
> >>
> >> diff --git a/io/statx.h b/io/statx.h
> >> index c6625ac4..d151f732 100644
> >> --- a/io/statx.h
> >> +++ b/io/statx.h
> >> @@ -61,6 +61,7 @@ struct statx_timestamp {
> >> __s32 tv_nsec;
> >> __s32 __reserved;
> >> };
> >> +#endif
> >>
> >> /*
> >> * Structures for the extended file attribute retrieval system call
> >> @@ -99,6 +100,8 @@ struct statx_timestamp {
> >> * will have values installed for compatibility purposes so that stat() and
> >> * co. can be emulated in userspace.
> >> */
> >> +#if !defined STATX_TYPE || defined OVERRIDE_SYSTEM_STATX
> >
> > Is there any place where STATX_TYPE is not defined but
> > OVERRIDE_SYSTEM_STATX will *also* not be defined?
>
> I don’t think so. So I guess this could just be
>
> #ifdef OVERRIDE_SYSTEM_STATX
>
> Does that seem right?
It seems ok to me.
--D
> >
> > I think the m4 macro you added sets need_internal_statx=yes for old
> > systems where there's no STATX_TYPE, because there won't be a struct
> > statx, let alone atomic_write_* fields in it, right?
> >
> > --D
> >
> >> +#undef statx
> >> struct statx {
> >> /* 0x00 */
> >> __u32 stx_mask; /* What results were written [uncond] */
> >> @@ -126,10 +129,23 @@ struct statx {
> >> __u32 stx_dev_major; /* ID of device containing file [uncond] */
> >> __u32 stx_dev_minor;
> >> /* 0x90 */
> >> - __u64 __spare2[14]; /* Spare space for future expansion */
> >> + __u64 stx_mnt_id;
> >> + __u32 stx_dio_mem_align; /* Memory buffer alignment for direct I/O */
> >> + __u32 stx_dio_offset_align; /* File offset alignment for direct I/O */
> >> + /* 0xa0 */
> >> + __u64 stx_subvol; /* Subvolume identifier */
> >> + __u32 stx_atomic_write_unit_min; /* Min atomic write unit in bytes */
> >> + __u32 stx_atomic_write_unit_max; /* Max atomic write unit in bytes */
> >> + /* 0xb0 */
> >> + __u32 stx_atomic_write_segments_max; /* Max atomic write segment count */
> >> + __u32 __spare1[1];
> >> + /* 0xb8 */
> >> + __u64 __spare3[9]; /* Spare space for future expansion */
> >> /* 0x100 */
> >> };
> >> +#endif
> >>
> >> +#ifndef STATX_TYPE
> >> /*
> >> * Flags to be stx_mask
> >> *
> >> @@ -174,4 +190,9 @@ struct statx {
> >> #define STATX_ATTR_AUTOMOUNT 0x00001000 /* Dir: Automount trigger */
> >>
> >> #endif /* STATX_TYPE */
> >> +
> >> +#ifndef STATX_WRITE_ATOMIC
> >> +#define STATX_WRITE_ATOMIC 0x00010000U /* Want/got atomic_write_* fields */
> >> +#endif
> >> +
> >> #endif /* XFS_IO_STATX_H */
> >> diff --git a/m4/package_libcdev.m4 b/m4/package_libcdev.m4
> >> index 6de8b33e..bc8a49a9 100644
> >> --- a/m4/package_libcdev.m4
> >> +++ b/m4/package_libcdev.m4
> >> @@ -98,6 +98,26 @@ AC_DEFUN([AC_NEED_INTERNAL_FSCRYPT_POLICY_V2],
> >> AC_SUBST(need_internal_fscrypt_policy_v2)
> >> ])
> >>
> >> +#
> >> +# Check if we need to override the system struct statx with
> >> +# the internal definition. This /only/ happens if the system
> >> +# actually defines struct statx /and/ the system definition
> >> +# is missing certain fields.
> >> +#
> >> +AC_DEFUN([AC_NEED_INTERNAL_STATX],
> >> + [ AC_CHECK_TYPE(struct statx,
> >> + [
> >> + AC_CHECK_MEMBER(struct statx.stx_atomic_write_unit_min,
> >> + ,
> >> + need_internal_statx=yes,
> >> + [#include <linux/stat.h>]
> >> + )
> >> + ],,
> >> + [#include <linux/stat.h>]
> >> + )
> >> + AC_SUBST(need_internal_statx)
> >> + ])
> >> +
> >> #
> >> # Check if we have a FS_IOC_GETFSMAP ioctl (Linux)
> >> #
> >> --
> >> 2.34.1
> >>
> >>
>
