[PATCH] NFS: Correct timing for assigning access cache timestamp

From: Chengen Du
Date: Wed Mar 08 2023 - 03:04:03 EST


When the user's login time is newer than the cache's timestamp,
the original entry in the RB-tree will be replaced by a new entry.
Currently, the timestamp is only set if the entry is not found in
the RB-tree, which can cause the timestamp to be undefined when
the entry exists. This may result in a significant increase in
ACCESS operations if the timestamp is set to zero.

Signed-off-by: Chengen Du <chengen.du@xxxxxxxxxxxxx>
---
fs/nfs/dir.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index a41c3ee4549c..6fbcbb8d6587 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -3089,7 +3089,6 @@ static void nfs_access_add_rbtree(struct inode *inode,
else
goto found;
}
- set->timestamp = ktime_get_ns();
rb_link_node(&set->rb_node, parent, p);
rb_insert_color(&set->rb_node, root_node);
list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
@@ -3114,6 +3113,7 @@ void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set,
cache->fsgid = cred->fsgid;
cache->group_info = get_group_info(cred->group_info);
cache->mask = set->mask;
+ cache->timestamp = ktime_get_ns();

/* The above field assignments must be visible
* before this item appears on the lru. We cannot easily
--
2.37.2