@@ -17,6 +17,7 @@
#include "xfs_trans_priv.h"
#include "xfs_qm.h"
#include "xfs_log.h"
+#include "xfs_log_priv.h"
static inline struct xfs_dq_logitem *DQUOT_ITEM(struct xfs_log_item *lip)
{
@@ -298,6 +299,13 @@ xfs_qm_qoff_logitem_push(
struct xfs_log_item *lip,
struct list_head *buffer_list)
{
+ struct xfs_log_item *mlip = xfs_ail_min(lip->li_ailp);
+
+ if (test_bit(XFS_LI_RELOG, &lip->li_flags) &&
+ !test_bit(XFS_LI_RELOG_QUEUED, &lip->li_flags) &&
+ !XFS_LSN_CMP(lip->li_lsn, mlip->li_lsn))
+ return XFS_ITEM_RELOG;
+
return XFS_ITEM_LOCKED;
}
@@ -329,6 +337,23 @@ xfs_qm_qoff_logitem_release(
}
}
+STATIC void
+xfs_qm_qoff_logitem_relog(
+ struct xfs_log_item *lip,
+ struct xfs_trans *tp)
+{
+ int res;
+
+ res = xfs_relog_calc_res(lip);
+
+ xfs_trans_add_item(tp, lip);
+ tp->t_ticket->t_curr_res += res;
+ tp->t_ticket->t_unit_res += res;
+ tp->t_log_res += res;
+ tp->t_flags |= XFS_TRANS_DIRTY;
+ set_bit(XFS_LI_DIRTY, &lip->li_flags);
+}
+
static const struct xfs_item_ops xfs_qm_qoffend_logitem_ops = {
.iop_size = xfs_qm_qoff_logitem_size,
.iop_format = xfs_qm_qoff_logitem_format,
@@ -342,6 +367,7 @@ static const struct xfs_item_ops xfs_qm_qoff_logitem_ops = {
.iop_format = xfs_qm_qoff_logitem_format,
.iop_push = xfs_qm_qoff_logitem_push,
.iop_release = xfs_qm_qoff_logitem_release,
+ .iop_relog = xfs_qm_qoff_logitem_relog,
};
/*
@@ -18,6 +18,7 @@
#include "xfs_quota.h"
#include "xfs_qm.h"
#include "xfs_icache.h"
+#include "xfs_trans_priv.h"
STATIC int
xfs_qm_log_quotaoff(
@@ -29,12 +30,14 @@ xfs_qm_log_quotaoff(
int error;
struct xfs_qoff_logitem *qoffi;
- error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_quotaoff, 0, 0, 0, &tp);
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_quotaoff, 0, 0,
+ XFS_TRANS_RELOG, &tp);
if (error)
goto out;
qoffi = xfs_trans_get_qoff_item(tp, NULL, flags & XFS_ALL_QUOTA_ACCT);
xfs_trans_log_quotaoff_item(tp, qoffi);
+ xfs_trans_relog_item(tp, &qoffi->qql_item);
spin_lock(&mp->m_sb_lock);
mp->m_sb.sb_qflags = (mp->m_qflags & ~(flags)) & XFS_MOUNT_QUOTA_ALL;
@@ -71,6 +74,13 @@ xfs_qm_log_quotaoff_end(
if (error)
return error;
+ /*
+ * startqoff must be in the AIL and not the CIL when the end intent
+ * commits to ensure it is not readded to the AIL out of order. Wait on
+ * relog activity to drain to isolate startqoff to the AIL.
+ */
+ xfs_trans_relog_item_cancel(tp, &(*startqoff)->qql_item, true);
+
qoffi = xfs_trans_get_qoff_item(tp, *startqoff,
flags & XFS_ALL_QUOTA_ACCT);
xfs_trans_log_quotaoff_item(tp, qoffi);
The quotaoff operation has a rare but longstanding deadlock vector in terms of how the operation is logged. A quotaoff start intent is logged (synchronously) at the onset to ensure recovery can handle the operation if interrupted before in-core changes are made. This quotaoff intent pins the log tail while the quotaoff sequence scans and purges dquots from all in-core inodes. While this operation generally doesn't generate much log traffic on its own, it can be time consuming. If unrelated, concurrent filesystem activity consumes remaining log space before quotaoff is able to acquire log reservation for the quotaoff end intent, the filesystem locks up indefinitely. quotaoff cannot allocate the end intent before the scan because the latter can result in transaction allocation itself in certain indirect cases (releasing an inode, for example). Further, rolling the original transaction is difficult because the scanning work occurs multiple layers down where caller context is lost and not much information is available to determine how often to roll the transaction. To address this problem, enable automatic relogging of the quotaoff start intent. This automatically relogs the intent whenever AIL pushing finds the item at the tail of the log. When quotaoff completes, wait for relogging to complete as the end intent expects to be able to permanently remove the start intent from the log subsystem. This ensures that the log tail is kept moving during a particularly long quotaoff operation and avoids the log reservation deadlock. Note that the quotaoff reservation calculation does not need to be updated for relog as it already (incorrectly) accounts for two quotaoff intents. Signed-off-by: Brian Foster <bfoster@redhat.com> --- fs/xfs/xfs_dquot_item.c | 26 ++++++++++++++++++++++++++ fs/xfs/xfs_qm_syscalls.c | 12 +++++++++++- 2 files changed, 37 insertions(+), 1 deletion(-)