[PATCH 3/5] xfs: add XFS_ITEM_UNSAFE for log item push return result

Long Li
2024-08-23T11:09:37Z

After pushing log items, the log item may have been freed, making it
unsafe to access in tracepoints. This commit introduces XFS_ITEM_UNSAFE
to indicate when an item might be freed during the item push operation.

Signed-off-by: Long Li <leo.lilong@huawei.com>
---
fs/xfs/xfs_stats.h | 1 +
fs/xfs/xfs_trans.h | 1 +
fs/xfs/xfs_trans_ail.c | 7 +++++++
3 files changed, 9 insertions(+)

diff --git a/fs/xfs/xfs_stats.h b/fs/xfs/xfs_stats.h
index a61fb56ed2e6..9a7a020587cf 100644
--- a/fs/xfs/xfs_stats.h
+++ b/fs/xfs/xfs_stats.h
@@ -86,6 +86,7 @@ struct __xfsstats {
uint32_t xs_push_ail_pushbuf;
uint32_t xs_push_ail_pinned;
uint32_t xs_push_ail_locked;
+ uint32_t xs_push_ail_unsafe;
uint32_t xs_push_ail_flushing;
uint32_t xs_push_ail_restarts;
uint32_t xs_push_ail_flush;
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index f06cc0f41665..fd4f04853fe2 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -117,6 +117,7 @@ void xfs_log_item_init(struct xfs_mount *mp, struct xfs_log_item *item,
#define XFS_ITEM_PINNED 1
#define XFS_ITEM_LOCKED 2
#define XFS_ITEM_FLUSHING 3
+#define XFS_ITEM_UNSAFE 4

/*
* This is the structure maintained for every active transaction.
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
index 8ede9d099d1f..a5ab1ffb8937 100644
--- a/fs/xfs/xfs_trans_ail.c
+++ b/fs/xfs/xfs_trans_ail.c
@@ -561,6 +561,13 @@ xfsaild_push(

stuck++;
break;
+ case XFS_ITEM_UNSAFE:
+ /*
+ * The item may have been freed, so we can't access the
+ * log item here.
+ */
+ XFS_STATS_INC(mp, xs_push_ail_unsafe);
+ break;
default:
ASSERT(0);
break;
--
2.39.2