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

Allison Collins
2019-06-06T22:37:45Z

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.

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 */
>>>