From 029085b8949f5d269ae2bbd14915407dd0c7f902 Mon Sep 17 00:00:00 2001 From: Chengen Du Date: Fri, 30 Dec 2022 11:04:32 +0800 Subject: [PATCH] NFS: Judge the file access cache's timestamp in rcu path If the user's login time is newer than the cache's timestamp, we expect the cache may be stale and need to clear. The stale cache will remain in the list's tail if no other users operate on that inode. Once the user accesses the inode, the stale cache will be returned in rcu path. Signed-off-by: Chengen Du Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index ea1ceffa1d3a..d490d64a9ebd 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -3023,6 +3023,7 @@ static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cre * but do it without locking. */ struct nfs_inode *nfsi = NFS_I(inode); + u64 login_time = nfs_access_login_time(current, cred); struct nfs_access_entry *cache; int err = -ECHILD; struct list_head *lh; @@ -3037,6 +3038,8 @@ static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cre cache = NULL; if (cache == NULL) goto out; + if ((s64)(login_time - cache->timestamp) > 0) + goto out; if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) goto out; *mask = cache->mask;