diff mbox

[3/3] NFS: Optimise away lookups for rename targets

Message ID 20180510192858.18539-3-trond.myklebust@hammerspace.com (mailing list archive)
State New, archived
Headers show

Commit Message

Trond Myklebust May 10, 2018, 7:28 p.m. UTC 
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 <trond.myklebust@hammerspace.com>
---
 fs/nfs/dir.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 9dde88334c9c..b315f53b3aec 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1051,13 +1051,15 @@  int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags)
  *
  * 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);