Commit 9f6d44d4 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

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: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 73dd684a

fs/nfs/dir.c

+5 −3
Original line number Diff line number Diff line
@@ -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);