[PATCH 2/5] xfs: use xfs_ilock_map_shared in xfs_qm_dqtobp

Christoph Hellwig
2013-12-05T15:59:53Z

[-- Attachment #1: xfs-quota-locking --]
[-- Type: text/plain, Size: 1417 bytes --]

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>

Index: xfs/fs/xfs/xfs_dquot.c
===================================================================
--- xfs.orig/fs/xfs/xfs_dquot.c 2013-11-18 14:39:01.955589999 +0100
+++ xfs/fs/xfs/xfs_dquot.c 2013-12-05 11:42:34.759679600 +0100
@@ -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_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_map_shared(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_map_shared(quotip, lock_mode);
if (error)
return error;