From 310ac6175787380f2bdb4ab913ad5f72149b9f20 Mon Sep 17 00:00:00 2001
From: Carlos Maiolino <cmaiolino@redhat.com>
Date: Tue, 8 Aug 2017 18:21:50 -0700
Subject: [PATCH 2/2] xfs: Properly retry failed inode items in case of error
during buffer writeback
Git-commit: d3a304b6292168b83b45d624784f973fdc1ca674
Patch-mainline: v4.14-rc1
References: bsc#1070682
When a buffer has been failed during writeback, the inode items into it
are kept flush locked, and are never resubmitted due the flush lock, so,
if any buffer fails to be written, the items in AIL are never written to
disk and never unlocked.
This causes unmount operation to hang due these items flush locked in AIL,
but this also causes the items in AIL to never be written back, even when
the IO device comes back to normal.
I've been testing this patch with a DM-thin device, creating a
filesystem larger than the real device.
When writing enough data to fill the DM-thin device, XFS receives ENOSPC
errors from the device, and keep spinning on xfsaild (when 'retry
forever' configuration is set).
At this point, the filesystem can not be unmounted because of the flush locked
items in AIL, but worse, the items in AIL are never retried at all
(once xfs_inode_item_push() will skip the items that are flush locked),
even if the underlying DM-thin device is expanded to the proper size.
This patch fixes both cases, retrying any item that has been failed
previously, using the infra-structure provided by the previous patch.
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
fs/xfs/xfs_buf_item.c | 28 ++++++++++++++++++++++++++++
fs/xfs/xfs_buf_item.h | 3 +++
fs/xfs/xfs_inode_item.c | 47 +++++++++++++++++++++++++++++++++++++++++++----
fs/xfs/xfs_trans.h | 1 +
fs/xfs/xfs_trans_ail.c | 3 ++-
fs/xfs/xfs_trans_priv.h | 31 +++++++++++++++++++++++++++++++
6 files changed, 108 insertions(+), 5 deletions(-)
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 9433d277619d..c215fc4e1dc6 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -1231,3 +1231,31 @@ xfs_buf_iodone(
xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
xfs_buf_item_free(BUF_ITEM(lip));
}
+
+/*
+ * Requeue a failed buffer for writeback
+ *
+ * Return true if the buffer has been re-queued properly, false otherwise
+ */
+bool
+xfs_buf_resubmit_failed_buffers(
+ struct xfs_buf *bp,
+ struct xfs_log_item *lip,
+ struct list_head *buffer_list)
+{
+ struct xfs_log_item *next;
+
+ /*
+ * Clear XFS_LI_FAILED flag from all items before resubmit
+ *
+ * XFS_LI_FAILED set/clear is protected by xa_lock, caller this
+ * function already have it acquired
+ */
+ for (; lip; lip = next) {
+ next = lip->li_bio_list;
+ xfs_clear_li_failed(lip);
+ }
+
+ /* Add this buffer back to the delayed write list */
+ return xfs_buf_delwri_queue(bp, buffer_list);
+}
diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index f7eba99d19dd..530686e1afb9 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -70,6 +70,9 @@ void xfs_buf_attach_iodone(struct xfs_buf *,
xfs_log_item_t *);
void xfs_buf_iodone_callbacks(struct xfs_buf *);
void xfs_buf_iodone(struct xfs_buf *, struct xfs_log_item *);
+bool xfs_buf_resubmit_failed_buffers(struct xfs_buf *,
+ struct xfs_log_item *,
+ struct list_head *);
extern kmem_zone_t *xfs_buf_item_zone;
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 013cc78d7daf..6d0f74ec31e8 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -27,6 +27,7 @@
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_trans_priv.h"
+#include "xfs_buf_item.h"
#include "xfs_log.h"
@@ -475,6 +476,23 @@ xfs_inode_item_unpin(
wake_up_bit(&ip->i_flags, __XFS_IPINNED_BIT);
}
+/*
+ * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
+ * have been failed during writeback
+ *
+ * This informs the AIL that the inode is already flush locked on the next push,
+ * and acquires a hold on the buffer to ensure that it isn't reclaimed before
+ * dirty data makes it to disk.
+ */
+STATIC void
+xfs_inode_item_error(
+ struct xfs_log_item *lip,
+ struct xfs_buf *bp)
+{
+ ASSERT(xfs_isiflocked(INODE_ITEM(lip)->ili_inode));
+ xfs_set_li_failed(lip, bp);
+}
+
STATIC uint
xfs_inode_item_push(
struct xfs_log_item *lip,
@@ -484,13 +502,28 @@ xfs_inode_item_push(
{
struct xfs_inode_log_item *iip = INODE_ITEM(lip);
struct xfs_inode *ip = iip->ili_inode;
- struct xfs_buf *bp = NULL;
+ struct xfs_buf *bp = lip->li_buf;
uint rval = XFS_ITEM_SUCCESS;
int error;
if (xfs_ipincount(ip) > 0)
return XFS_ITEM_PINNED;
+ /*
+ * The buffer containing this item failed to be written back
+ * previously. Resubmit the buffer for IO.
+ */
+ if (lip->li_flags & XFS_LI_FAILED) {
+ if (!xfs_buf_trylock(bp))
+ return XFS_ITEM_LOCKED;
+
+ if (!xfs_buf_resubmit_failed_buffers(bp, lip, buffer_list))
+ rval = XFS_ITEM_FLUSHING;
+
+ xfs_buf_unlock(bp);
+ return rval;
+ }
+
if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED))
return XFS_ITEM_LOCKED;
@@ -622,7 +655,8 @@ static const struct xfs_item_ops xfs_inode_item_ops = {
.iop_unlock = xfs_inode_item_unlock,
.iop_committed = xfs_inode_item_committed,
.iop_push = xfs_inode_item_push,
- .iop_committing = xfs_inode_item_committing
+ .iop_committing = xfs_inode_item_committing,
+ .iop_error = xfs_inode_item_error
};
@@ -710,7 +744,8 @@ xfs_iflush_done(
* the AIL lock.
*/
iip = INODE_ITEM(blip);
- if (iip->ili_logged && blip->li_lsn == iip->ili_flush_lsn)
+ if ((iip->ili_logged && blip->li_lsn == iip->ili_flush_lsn) ||
+ lip->li_flags & XFS_LI_FAILED)
need_ail++;
blip = next;
@@ -718,7 +753,8 @@ xfs_iflush_done(
/* make sure we capture the state of the initial inode. */
iip = INODE_ITEM(lip);
- if (iip->ili_logged && lip->li_lsn == iip->ili_flush_lsn)
+ if ((iip->ili_logged && lip->li_lsn == iip->ili_flush_lsn) ||
+ lip->li_flags & XFS_LI_FAILED)
need_ail++;
/*
@@ -739,6 +775,9 @@ xfs_iflush_done(
if (INODE_ITEM(blip)->ili_logged &&
blip->li_lsn == INODE_ITEM(blip)->ili_flush_lsn)
mlip_changed |= xfs_ail_delete_one(ailp, blip);
+ else {
+ xfs_clear_li_failed(blip);
+ }
}
if (mlip_changed) {
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 50df53673cce..9bc15ca53ee3 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -49,6 +49,7 @@ typedef struct xfs_log_item {
struct xfs_ail *li_ailp; /* ptr to AIL */
uint li_type; /* item type */
uint li_flags; /* misc flags */
+ struct xfs_buf *li_buf; /* real buffer pointer */
struct xfs_log_item *li_bio_list; /* buffer item list */
void (*li_cb)(struct xfs_buf *,
struct xfs_log_item *);
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
index 9056c0f34a3c..70f5ab017323 100644
--- a/fs/xfs/xfs_trans_ail.c
+++ b/fs/xfs/xfs_trans_ail.c
@@ -687,12 +687,13 @@ xfs_trans_ail_update_bulk(
bool
xfs_ail_delete_one(
struct xfs_ail *ailp,
- struct xfs_log_item *lip)
+ struct xfs_log_item *lip)
{
struct xfs_log_item *mlip = xfs_ail_min(ailp);
trace_xfs_ail_delete(lip, mlip->li_lsn, lip->li_lsn);
xfs_ail_delete(ailp, lip);
+ xfs_clear_li_failed(lip);
lip->li_flags &= ~XFS_LI_IN_AIL;
lip->li_lsn = 0;
diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h
index d91706c56c63..b317a3644c00 100644
--- a/fs/xfs/xfs_trans_priv.h
+++ b/fs/xfs/xfs_trans_priv.h
@@ -164,4 +164,35 @@ xfs_trans_ail_copy_lsn(
*dst = *src;
}
#endif
+
+static inline void
+xfs_clear_li_failed(
+ struct xfs_log_item *lip)
+{
+ struct xfs_buf *bp = lip->li_buf;
+
+ ASSERT(lip->li_flags & XFS_LI_IN_AIL);
+ lockdep_assert_held(&lip->li_ailp->xa_lock);
+
+ if (lip->li_flags & XFS_LI_FAILED) {
+ lip->li_flags &= ~XFS_LI_FAILED;
+ lip->li_buf = NULL;
+ xfs_buf_rele(bp);
+ }
+}
+
+static inline void
+xfs_set_li_failed(
+ struct xfs_log_item *lip,
+ struct xfs_buf *bp)
+{
+ lockdep_assert_held(&lip->li_ailp->xa_lock);
+
+ if (!(lip->li_flags & XFS_LI_FAILED)) {
+ xfs_buf_hold(bp);
+ lip->li_flags |= XFS_LI_FAILED;
+ lip->li_buf = bp;
+ }
+}
+
#endif /* __XFS_TRANS_PRIV_H__ */
--
2.15.0