With the current code, XFS never re-submit a failed buffer for IO,
because the failed item in the buffer is kept in the flush locked state
forever.
To be able to resubmit an log item for IO, we need a way to mark an item
as failed, if, for any reason the buffer which the item belonged to
failed during writeback.
Add a new log item callback to be used after an IO completion failure
and make the needed clean ups.
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
---
V2:
- Update commit log to include a better description of why this
patch is needed and fix spelling mistakes
- Move xfs_buf_do_callbacks_fail() call into
xfs_buf_iodone_callback_error, so the callbacks can be executed
before the buffer is released, and only after it has been
retried once
V3:
- fix some loops according to hch suggestion
- whitespace cleanup
V4:
- Invoke failure callbacks before reset the I/O error
- Remove bflags field from iop_error callback
- move spin_lock/unlock xa_lock up in the stack, handling all
log items in the same buffer into a single lock
V5:
- Reorganize variable declarations
in fxs_buf_do_callbacks_fail
V6:
- Add a comment to xfs_buf_do_callbacks_fail
fs/xfs/xfs_buf_item.c | 32 +++++++++++++++++++++++++++++++-
fs/xfs/xfs_trans.h | 7 +++++--
2 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index f6a8422..7573a1f 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -29,6 +29,7 @@
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_log.h"
+#include "xfs_inode.h"
kmem_zone_t *xfs_buf_item_zone;
@@ -1054,6 +1055,31 @@ xfs_buf_do_callbacks(
}
}
+/*
+ * Invoke the error state callback for each log item affected by the failed I/O.
+ *
+ * If a metadata buffer write fails with a non-permanent error, the buffer is
+ * eventually resubmitted and so the completion callbacks are not run. The error
+ * state may need to be propagated to the log items attached to the buffer,
+ * however, so the next AIL push of the item knows hot to handle it correctly.
+ */
+STATIC void
+xfs_buf_do_callbacks_fail(
+ struct xfs_buf *bp)
+{
+ struct xfs_log_item *next;
+ struct xfs_log_item *lip = bp->b_fspriv;
+ struct xfs_ail *ailp = lip->li_ailp;
+
+ spin_lock(&ailp->xa_lock);
+ for (; lip; lip = next) {
+ next = lip->li_bio_list;
+ if (lip->li_ops->iop_error)
+ lip->li_ops->iop_error(lip, bp);
+ }
+ spin_unlock(&ailp->xa_lock);
+}
+
static bool
xfs_buf_iodone_callback_error(
struct xfs_buf *bp)
@@ -1123,7 +1149,11 @@ xfs_buf_iodone_callback_error(
if ((mp->m_flags & XFS_MOUNT_UNMOUNTING) && mp->m_fail_unmount)
goto permanent_error;
- /* still a transient error, higher layers will retry */
+ /*
+ * Still a transient error, run IO completion failure callbacks and let
+ * the higher layers retry the buffer.
+ */
+ xfs_buf_do_callbacks_fail(bp);
xfs_buf_ioerror(bp, 0);
xfs_buf_relse(bp);
return true;
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 6bdad6f..442d679 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -64,11 +64,13 @@ typedef struct xfs_log_item {
} xfs_log_item_t;
#define XFS_LI_IN_AIL 0x1
-#define XFS_LI_ABORTED 0x2
+#define XFS_LI_ABORTED 0x2
+#define XFS_LI_FAILED 0x4
#define XFS_LI_FLAGS \
{ XFS_LI_IN_AIL, "IN_AIL" }, \
- { XFS_LI_ABORTED, "ABORTED" }
+ { XFS_LI_ABORTED, "ABORTED" }, \
+ { XFS_LI_FAILED, "FAILED" }
struct xfs_item_ops {
void (*iop_size)(xfs_log_item_t *, int *, int *);
@@ -79,6 +81,7 @@ struct xfs_item_ops {
void (*iop_unlock)(xfs_log_item_t *);
xfs_lsn_t (*iop_committed)(xfs_log_item_t *, xfs_lsn_t);
void (*iop_committing)(xfs_log_item_t *, xfs_lsn_t);
+ void (*iop_error)(xfs_log_item_t *, xfs_buf_t *);
};
void xfs_log_item_init(struct xfs_mount *mp, struct xfs_log_item *item,
--
2.9.4
--
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