On Sun, Jun 25, 2017 at 11:04:46PM -0700, Darrick J. Wong wrote:
> Add a new dqget flag that grabs the dquot without taking the ilock.
> This will be used by the scrubber (which will have already grabbed
> the ilock) to perform basic sanity checking of the quota data.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
It might be good to add an assert somewhere after where we expect the
lock to be held one way or another. Otherwise looks Ok to me:
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> fs/xfs/libxfs/xfs_quota_defs.h | 2 ++
> fs/xfs/xfs_dquot.c | 11 +++++++----
> 2 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_quota_defs.h b/fs/xfs/libxfs/xfs_quota_defs.h
> index d69c772..2834574 100644
> --- a/fs/xfs/libxfs/xfs_quota_defs.h
> +++ b/fs/xfs/libxfs/xfs_quota_defs.h
> @@ -136,6 +136,8 @@ typedef uint16_t xfs_qwarncnt_t;
> */
> #define XFS_QMOPT_INHERIT 0x1000000
>
> +#define XFS_QMOPT_NOLOCK 0x2000000 /* don't ilock during dqget */
> +
> /*
> * flags to xfs_trans_mod_dquot.
> */
> diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
> index e57c6cc..3519efc 100644
> --- a/fs/xfs/xfs_dquot.c
> +++ b/fs/xfs/xfs_dquot.c
> @@ -472,18 +472,20 @@ xfs_qm_dqtobp(
> struct xfs_mount *mp = dqp->q_mount;
> xfs_dqid_t id = be32_to_cpu(dqp->q_core.d_id);
> struct xfs_trans *tp = (tpp ? *tpp : NULL);
> - uint lock_mode;
> + uint lock_mode = 0;
>
> quotip = xfs_quota_inode(dqp->q_mount, dqp->dq_flags);
> dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;
>
> - lock_mode = xfs_ilock_data_map_shared(quotip);
> + if (!(flags & XFS_QMOPT_NOLOCK))
> + lock_mode = xfs_ilock_data_map_shared(quotip);
> if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
> /*
> * Return if this type of quotas is turned off while we
> * didn't have the quota inode lock.
> */
> - xfs_iunlock(quotip, lock_mode);
> + if (lock_mode)
> + xfs_iunlock(quotip, lock_mode);
> return -ESRCH;
> }
>
> @@ -493,7 +495,8 @@ xfs_qm_dqtobp(
> error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
> XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);
>
> - xfs_iunlock(quotip, lock_mode);
> + if (lock_mode)
> + xfs_iunlock(quotip, lock_mode);
> if (error)
> return error;
>
> --
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