Re: [PATCH 5/9] xfs: wire up new v5 bulkstat ioctls

Darrick J. Wong
2019-06-07T16:11:00Z

On Thu, Jun 06, 2019 at 03:37:40PM -0700, Allison Collins wrote:
> On 6/6/19 2:10 PM, Darrick J. Wong wrote:
> > On Wed, Jun 05, 2019 at 03:30:21PM -0700, Allison Collins wrote:
> > > On 5/29/19 3:28 PM, Darrick J. Wong wrote:
> > > > From: Darrick J. Wong <darrick.wong@oracle.com>
> > > >
> > > > Wire up the new v5 BULKSTAT ioctl and rename the old one to V1.
> > > >
> > > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > > > ---
> > > > fs/xfs/libxfs/xfs_fs.h | 24 +++++++++++
> > > > fs/xfs/xfs_ioctl.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++
> > > > fs/xfs/xfs_ioctl32.c | 1
> > > > fs/xfs/xfs_ondisk.h | 1
> > > > 4 files changed, 129 insertions(+), 1 deletion(-)
> > > >
> > > >
> > > > diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
> > > > index 8b8fe78511fb..960f3542e207 100644
> > > > --- a/fs/xfs/libxfs/xfs_fs.h
> > > > +++ b/fs/xfs/libxfs/xfs_fs.h
> > > > @@ -435,7 +435,6 @@ struct xfs_fsop_bulkreq {
> > > > __s32 __user *ocount; /* output count pointer */
> > > > };
> > > > -
> > > > /*
> > > > * Structures returned from xfs_inumbers routine (XFS_IOC_FSINUMBERS).
> > > > */
> > > > @@ -457,6 +456,28 @@ struct xfs_inumbers {
> > > > #define XFS_INUMBERS_VERSION_V1 (1)
> > > > #define XFS_INUMBERS_VERSION_V5 (5)
> > > > +/* Header for bulk inode requests. */
> > > > +struct xfs_bulk_ireq {
> > > > + uint64_t ino; /* I/O: start with this inode */
> > > > + uint32_t flags; /* I/O: operation flags */
> > > > + uint32_t icount; /* I: count of entries in buffer */
> > > > + uint32_t ocount; /* O: count of entries filled out */
> > > > + uint32_t reserved32; /* must be zero */
> > > > + uint64_t reserved[5]; /* must be zero */
> > > > +};
> > > > +
> > > > +#define XFS_BULK_IREQ_FLAGS_ALL (0)
> > > > +
> > > > +/*
> > > > + * ioctl structures for v5 bulkstat and inumbers requests
> > > > + */
> > > > +struct xfs_bulkstat_req {
> > > > + struct xfs_bulk_ireq hdr;
> > > > + struct xfs_bulkstat bulkstat[];
> > > > +};
> > > > +#define XFS_BULKSTAT_REQ_SIZE(nr) (sizeof(struct xfs_bulkstat_req) + \
> > > > + (nr) * sizeof(struct xfs_bulkstat))
> > > > +
> > > > /*
> > > > * Error injection.
> > > > */
> > > > @@ -758,6 +779,7 @@ struct xfs_scrub_metadata {
> > > > #define XFS_IOC_FSGEOMETRY_V4 _IOR ('X', 124, struct xfs_fsop_geom_v4)
> > > > #define XFS_IOC_GOINGDOWN _IOR ('X', 125, uint32_t)
> > > > #define XFS_IOC_FSGEOMETRY _IOR ('X', 126, struct xfs_fsop_geom)
> > > > +#define XFS_IOC_BULKSTAT _IOR ('X', 127, struct xfs_bulkstat_req)
> > > > /* XFS_IOC_GETFSUUID ---------- deprecated 140 */
> > > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> > > > index e43ad688e683..f6724c75ba97 100644
> > > > --- a/fs/xfs/xfs_ioctl.c
> > > > +++ b/fs/xfs/xfs_ioctl.c
> > > > @@ -822,6 +822,107 @@ xfs_ioc_fsbulkstat(
> > > > return 0;
> > > > }
> > > > +/* Return 0 on success or positive error */
> > > > +static int
> > > > +xfs_bulkstat_fmt(
> > > > + struct xfs_ibulk *breq,
> > > > + const struct xfs_bulkstat *bstat)
> > > > +{
> > > > + if (copy_to_user(breq->ubuffer, bstat, sizeof(struct xfs_bulkstat)))
> > > > + return -EFAULT;
> > > > + return xfs_ibulk_advance(breq, sizeof(struct xfs_bulkstat));
> > > > +}
> > > > +
> > > > +/*
> > > > + * Check the incoming bulk request @hdr from userspace and initialize the
> > > > + * internal @breq bulk request appropriately. Returns 0 if the bulk request
> > > > + * should proceed; 1 if there's nothing to do; or the usual negative error
> > > > + * code.
> > > > + */
> > > > +static int
> > > > +xfs_bulk_ireq_setup(
> > > > + struct xfs_mount *mp,
> > > > + struct xfs_bulk_ireq *hdr,
> > > > + struct xfs_ibulk *breq,
> > > > + void __user *ubuffer)
> > > > +{
> > > > + if (hdr->icount == 0 ||
> > > > + (hdr->flags & ~XFS_BULK_IREQ_FLAGS_ALL) ||
> > > > + hdr->reserved32 ||
> > > > + memchr_inv(hdr->reserved, 0, sizeof(hdr->reserved)))
> > > > + return -EINVAL;
> > > > +
> > > > + if (XFS_INO_TO_AGNO(mp, hdr->ino) >= mp->m_sb.sb_agcount)
> > > > + goto no_results;
> > > > +
> > > > + breq->ubuffer = ubuffer;
> > > > + breq->icount = hdr->icount;
> > > > + breq->startino = hdr->ino;
> > > > + return 0;
> > > > +no_results:
> > > > + hdr->ocount = 0;
> > > > + return 1;
> > > > +}
> > > > +
> > > > +/*
> > > > + * Update the userspace bulk request @hdr to reflect the end state of the
> > > > + * internal bulk request @breq. If @error is negative then we return just
> > > > + * that; otherwise (@error is 0 or 1) we copy the state so that userspace
> > > > + * can discover what happened.
> > > > + */
> > > > +static int
> > > > +xfs_bulk_ireq_teardown(
> > > > + struct xfs_bulk_ireq *hdr,
> > > > + struct xfs_ibulk *breq,
> > > > + int error)
> > > > +{
> > > > + if (error < 0)
> > > > + return error;
> > > Hmm, passing in error just to bail on error seemed a little out of scope to
> > > me. Is there a reason we're doing it here? Instead of after the preceding
> > > call made in the caller? Referenced below.....
> > >
> > > > +
> > > > + hdr->ino = breq->startino;
> > > > + hdr->ocount = breq->ocount;
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* Handle the v5 bulkstat ioctl. */
> > > > +STATIC int
> > > > +xfs_ioc_bulkstat(
> > > > + struct xfs_mount *mp,
> > > > + unsigned int cmd,
> > > > + struct xfs_bulkstat_req __user *arg)
> > > > +{
> > > > + struct xfs_bulk_ireq hdr;
> > > > + struct xfs_ibulk breq = {
> > > > + .mp = mp,
> > > > + };
> > > > + int error;
> > > > +
> > > > + if (!capable(CAP_SYS_ADMIN))
> > > > + return -EPERM;
> > > > +
> > > > + if (XFS_FORCED_SHUTDOWN(mp))
> > > > + return -EIO;
> > > > +
> > > > + if (copy_from_user(&hdr, &arg->hdr, sizeof(hdr)))
> > > > + return -EFAULT;
> > > > +
> > > > + error = xfs_bulk_ireq_setup(mp, &hdr, &breq, arg->bulkstat);
> > > > + if (error < 0)
> > > > + return error;
> > > > +
> > > > + if (!error)
> > > > + error = xfs_bulkstat(&breq, xfs_bulkstat_fmt);
> > > > +
> > > Right here. How about
> > >
> > > if (error < 0)
> > > return error;
> > >
> > > It seems functionally equivalent. If error < 0, teardown will
> > > bounce it back anyway and then the error check below will toss it back up.
> > > Is that what you meant?
> >
> > Yeah, I could do that too. :)
> >
> > TBH I only threw it in as a helper function because xfs_bulk_ireq_setup
> > seemed to need a counterpart; it's such a short function that I could
> > just opencode it... Thoughts?
> >
> > --D
>
> Sure, I'd be fine with open coding it too. I think I made a similar comment
> in patch 6 since these helper functions are so small. I think if you just
> add a comment or two about updating the header that would be fine.

I could even keep the teardown helper and just adjust the calling style:

error = xfs_bulk_ireq_setup(...);
if (error == 1)
goto teardown;
else if (error < 0)
goto out;

error = xfs_bulkstat(...);
if (error)
goto out;

teardown:
error = 0;
xfs_bulk_ireq_teardown(...);

if (copy_to_user(...)))
return -EFAULT;

out:
return error;

Yeah, maybe I'll do that, it's looks more like our normal practice.

--D

> Allison
>
> >
> > > Allison
> > >
> > > > + error = xfs_bulk_ireq_teardown(&hdr, &breq, error);
> > > > + if (error)
> > > > + return error;
> > > > +
> > > > + if (copy_to_user(&arg->hdr, &hdr, sizeof(hdr)))
> > > > + return -EFAULT;
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > STATIC int
> > > > xfs_ioc_fsgeometry(
> > > > struct xfs_mount *mp,
> > > > @@ -1986,6 +2087,9 @@ xfs_file_ioctl(
> > > > case XFS_IOC_FSINUMBERS:
> > > > return xfs_ioc_fsbulkstat(mp, cmd, arg);
> > > > + case XFS_IOC_BULKSTAT:
> > > > + return xfs_ioc_bulkstat(mp, cmd, arg);
> > > > +
> > > > case XFS_IOC_FSGEOMETRY_V1:
> > > > return xfs_ioc_fsgeometry(mp, arg, 3);
> > > > case XFS_IOC_FSGEOMETRY_V4:
> > > > diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
> > > > index bfe71747776b..84c342be4536 100644
> > > > --- a/fs/xfs/xfs_ioctl32.c
> > > > +++ b/fs/xfs/xfs_ioctl32.c
> > > > @@ -576,6 +576,7 @@ xfs_file_compat_ioctl(
> > > > case XFS_IOC_ERROR_CLEARALL:
> > > > case FS_IOC_GETFSMAP:
> > > > case XFS_IOC_SCRUB_METADATA:
> > > > + case XFS_IOC_BULKSTAT:
> > > > return xfs_file_ioctl(filp, cmd, p);
> > > > #if !defined(BROKEN_X86_ALIGNMENT) || defined(CONFIG_X86_X32)
> > > > /*
> > > > diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> > > > index d8f941b4d51c..954484c6eb96 100644
> > > > --- a/fs/xfs/xfs_ondisk.h
> > > > +++ b/fs/xfs/xfs_ondisk.h
> > > > @@ -149,6 +149,7 @@ xfs_check_ondisk_structs(void)
> > > > XFS_CHECK_STRUCT_SIZE(struct xfs_bulkstat, 192);
> > > > XFS_CHECK_STRUCT_SIZE(struct xfs_inumbers, 24);
> > > > + XFS_CHECK_STRUCT_SIZE(struct xfs_bulkstat_req, 64);
> > > > }
> > > > #endif /* __XFS_ONDISK_H */
> > > >