xfs: use xfs_ilock_data_map_shared in xfs_qm_dqtobp

We might not have read in the extent list at this point, so make sure we
take the ilock exclusively if we have to do so.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index 6b1e695caf0e..7aeb4c895b32 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -469,16 +469,17 @@ 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;
 
         dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;
 
-        xfs_ilock(quotip, XFS_ILOCK_SHARED);
+        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, XFS_ILOCK_SHARED);
+                xfs_iunlock(quotip, lock_mode);
                 return ESRCH;
         }
 
@@ -488,7 +489,7 @@ xfs_qm_dqtobp(
         error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
                                XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);
 
-        xfs_iunlock(quotip, XFS_ILOCK_SHARED);
+        xfs_iunlock(quotip, lock_mode);
         if (error)
                 return error;