xfs: grab dquots without taking the ilock

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@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
This commit is contained in:
Darrick J. Wong 2017-06-27 10:19:45 -07:00
parent 244e3dea58
commit 50e0bdbe9f
2 changed files with 12 additions and 4 deletions

View File

@ -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.
*/

View File

@ -472,18 +472,23 @@ 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);
ASSERT(!(flags & XFS_QMOPT_NOLOCK) ||
xfs_isilocked(quotip, XFS_ILOCK_SHARED) ||
xfs_isilocked(quotip, XFS_ILOCK_EXCL));
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 +498,8 @@ 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;