From 9f6d44d418b1f47298a92cd2dc42b8dba8b04816 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 10 May 2018 10:34:21 -0400 Subject: [PATCH] NFS: Optimise away lookups for rename targets We can optimise away any lookup for a rename target, unless we're being asked to revalidate a dentry that might be in use. Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 9dde883..b315f53 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1051,13 +1051,15 @@ out_force: * * If LOOKUP_RCU prevents us from performing a full check, return 1 * suggesting a reval is needed. + * + * Note that when creating a new file, or looking up a rename target, + * then it shouldn't be necessary to revalidate a negative dentry. */ static inline int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, unsigned int flags) { - /* Don't revalidate a negative dentry if we're creating a new file */ - if (flags & LOOKUP_CREATE) + if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) return 0; if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) return 1; @@ -1347,7 +1349,7 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in * If we're doing an exclusive create, optimize away the lookup * but don't hash the dentry. */ - if (nfs_is_exclusive_create(dir, flags)) + if (nfs_is_exclusive_create(dir, flags) || flags & LOOKUP_RENAME_TARGET) return NULL; res = ERR_PTR(-ENOMEM); -- 2.7.4