Commit ad1e109a authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Don't ask for readdirplus unless it can help nfs_getattr() 



If attribute caching is turned off, then use of readdirplus is not going
to help stat() performance.
Readdirplus also doesn't help if a file is being written to, since we
will have to flush those writes in order to sync the mtime/ctime.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 230bc98f

fs/nfs/inode.c

+25 −20
Original line number Diff line number Diff line
@@ -780,27 +780,33 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, 
}

EXPORT_SYMBOL_GPL(nfs_setattr_update_inode);



static void nfs_readdirplus_parent_cache_miss(struct dentry *dentry)

/*

 * Don't request help from readdirplus if the file is being written to,

 * or if attribute caching is turned off

 */

static bool nfs_getattr_readdirplus_enable(const struct inode *inode)

{

	struct dentry *parent;

	return nfs_server_capable(inode, NFS_CAP_READDIRPLUS) &&

	       !nfs_have_writebacks(inode) && NFS_MAXATTRTIMEO(inode) > 5 * HZ;

}



	if (!nfs_server_capable(d_inode(dentry), NFS_CAP_READDIRPLUS))

		return;

	parent = dget_parent(dentry);

static void nfs_readdirplus_parent_cache_miss(struct dentry *dentry)

{

	if (!IS_ROOT(dentry)) {

		struct dentry *parent = dget_parent(dentry);

		nfs_readdir_record_entry_cache_miss(d_inode(parent));

		dput(parent);

	}

}



static void nfs_readdirplus_parent_cache_hit(struct dentry *dentry)

{

	struct dentry *parent;



	if (!nfs_server_capable(d_inode(dentry), NFS_CAP_READDIRPLUS))

		return;

	parent = dget_parent(dentry);

	if (!IS_ROOT(dentry)) {

		struct dentry *parent = dget_parent(dentry);

		nfs_readdir_record_entry_cache_hit(d_inode(parent));

		dput(parent);

	}

}



static u32 nfs_get_valid_attrmask(struct inode *inode)

{
@@ -835,6 +841,7 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path, 
	int err = 0;

	bool force_sync = query_flags & AT_STATX_FORCE_SYNC;

	bool do_update = false;

	bool readdirplus_enabled = nfs_getattr_readdirplus_enable(inode);



	trace_nfs_getattr_enter(inode);
@@ -843,6 +850,7 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path, 
			STATX_INO | STATX_SIZE | STATX_BLOCKS;



	if ((query_flags & AT_STATX_DONT_SYNC) && !force_sync) {

		if (readdirplus_enabled)

			nfs_readdirplus_parent_cache_hit(path->dentry);

		goto out_no_revalidate;

	}
@@ -893,15 +901,12 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path, 
		do_update |= cache_validity & NFS_INO_INVALID_BLOCKS;



	if (do_update) {

		/* Update the attribute cache */

		if (!(server->flags & NFS_MOUNT_NOAC))

		if (readdirplus_enabled)

			nfs_readdirplus_parent_cache_miss(path->dentry);

		else

			nfs_readdirplus_parent_cache_hit(path->dentry);

		err = __nfs_revalidate_inode(server, inode);

		if (err)

			goto out;

	} else

	} else if (readdirplus_enabled)

		nfs_readdirplus_parent_cache_hit(path->dentry);

out_no_revalidate:

	/* Only return attributes that were revalidated. */