Commit 2396356a authored by Luis Henriques's avatar Luis Henriques Committed by Miklos Szeredi
Browse files

fuse: add more control over cache invalidation behaviour 



Currently userspace is able to notify the kernel to invalidate the cache
for an inode.  This means that, if all the inodes in a filesystem need to
be invalidated, then userspace needs to iterate through all of them and do
this kernel notification separately.

This patch adds the concept of 'epoch': each fuse connection will have the
current epoch initialized and every new dentry will have it's d_time set to
the current epoch value.  A new operation will then allow userspace to
increment the epoch value.  Every time a dentry is d_revalidate()'ed, it's
epoch is compared with the current connection epoch and invalidated if it's
value is different.

Signed-off-by: default avatarLuis Henriques <luis@igalia.com>
Tested-by: default avatarLaura Promberger <laura.promberger@cern.ch>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent faa794dd

fs/fuse/dev.c

+16 −0
Original line number Diff line number Diff line
@@ -2021,6 +2021,19 @@ static int fuse_notify_resend(struct fuse_conn *fc) 
	return 0;

}



/*

 * Increments the fuse connection epoch.  This will result of dentries from

 * previous epochs to be invalidated.

 *

 * XXX optimization: add call to shrink_dcache_sb()?

 */

static int fuse_notify_inc_epoch(struct fuse_conn *fc)

{

	atomic_inc(&fc->epoch);



	return 0;

}



static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,

		       unsigned int size, struct fuse_copy_state *cs)

{
@@ -2049,6 +2062,9 @@ static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 
	case FUSE_NOTIFY_RESEND:

		return fuse_notify_resend(fc);



	case FUSE_NOTIFY_INC_EPOCH:

		return fuse_notify_inc_epoch(fc);



	default:

		fuse_copy_finish(cs);

		return -EINVAL;

fs/fuse/dir.c

+22 −5
Original line number Diff line number Diff line
@@ -200,9 +200,14 @@ static int fuse_dentry_revalidate(struct inode *dir, const struct qstr *name, 
{

	struct inode *inode;

	struct fuse_mount *fm;

	struct fuse_conn *fc;

	struct fuse_inode *fi;

	int ret;



	fc = get_fuse_conn_super(dir->i_sb);

	if (entry->d_time < atomic_read(&fc->epoch))

		goto invalid;



	inode = d_inode_rcu(entry);

	if (inode && fuse_is_bad(inode))

		goto invalid;
@@ -415,16 +420,20 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name 
static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,

				  unsigned int flags)

{

	int err;

	struct fuse_entry_out outarg;

	struct fuse_conn *fc;

	struct inode *inode;

	struct dentry *newent;

	int err, epoch;

	bool outarg_valid = true;

	bool locked;



	if (fuse_is_bad(dir))

		return ERR_PTR(-EIO);



	fc = get_fuse_conn_super(dir->i_sb);

	epoch = atomic_read(&fc->epoch);



	locked = fuse_lock_inode(dir);

	err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,

			       &outarg, &inode);
@@ -446,6 +455,7 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, 
		goto out_err;



	entry = newent ? newent : entry;

	entry->d_time = epoch;

	if (outarg_valid)

		fuse_change_entry_timeout(entry, &outarg);

	else
@@ -619,7 +629,6 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir, 
			    struct dentry *entry, struct file *file,

			    unsigned int flags, umode_t mode, u32 opcode)

{

	int err;

	struct inode *inode;

	struct fuse_mount *fm = get_fuse_mount(dir);

	FUSE_ARGS(args);
@@ -629,11 +638,13 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir, 
	struct fuse_entry_out outentry;

	struct fuse_inode *fi;

	struct fuse_file *ff;

	int epoch, err;

	bool trunc = flags & O_TRUNC;



	/* Userspace expects S_IFREG in create mode */

	BUG_ON((mode & S_IFMT) != S_IFREG);



	epoch = atomic_read(&fm->fc->epoch);

	forget = fuse_alloc_forget();

	err = -ENOMEM;

	if (!forget)
@@ -702,6 +713,7 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir, 
	}

	kfree(forget);

	d_instantiate(entry, inode);

	entry->d_time = epoch;

	fuse_change_entry_timeout(entry, &outentry);

	fuse_dir_changed(dir);

	err = generic_file_open(inode, file);
@@ -788,12 +800,14 @@ static struct dentry *create_new_entry(struct mnt_idmap *idmap, struct fuse_moun 
	struct fuse_entry_out outarg;

	struct inode *inode;

	struct dentry *d;

	int err;

	struct fuse_forget_link *forget;

	int epoch, err;



	if (fuse_is_bad(dir))

		return ERR_PTR(-EIO);



	epoch = atomic_read(&fm->fc->epoch);



	forget = fuse_alloc_forget();

	if (!forget)

		return ERR_PTR(-ENOMEM);
@@ -835,10 +849,13 @@ static struct dentry *create_new_entry(struct mnt_idmap *idmap, struct fuse_moun 
	if (IS_ERR(d))

		return d;



	if (d)

	if (d) {

		d->d_time = epoch;

		fuse_change_entry_timeout(d, &outarg);

	else

	} else {

		entry->d_time = epoch;

		fuse_change_entry_timeout(entry, &outarg);

	}

	fuse_dir_changed(dir);

	return d;

fs/fuse/fuse_i.h

+3 −0
Original line number Diff line number Diff line
@@ -636,6 +636,9 @@ struct fuse_conn { 
	/** Number of fuse_dev's */

	atomic_t dev_count;



	/** Current epoch for up-to-date dentries */

	atomic_t epoch;



	struct rcu_head rcu;



	/** The user id for this mount */

fs/fuse/inode.c

+1 −0
Original line number Diff line number Diff line
@@ -962,6 +962,7 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, 
	init_rwsem(&fc->killsb);

	refcount_set(&fc->count, 1);

	atomic_set(&fc->dev_count, 1);

	atomic_set(&fc->epoch, 1);

	init_waitqueue_head(&fc->blocked_waitq);

	fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);

	INIT_LIST_HEAD(&fc->bg_queue);

fs/fuse/readdir.c

+3 −0
Original line number Diff line number Diff line
@@ -161,6 +161,7 @@ static int fuse_direntplus_link(struct file *file, 
	struct fuse_conn *fc;

	struct inode *inode;

	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);

	int epoch;



	if (!o->nodeid) {

		/*
@@ -190,6 +191,7 @@ static int fuse_direntplus_link(struct file *file, 
		return -EIO;



	fc = get_fuse_conn(dir);

	epoch = atomic_read(&fc->epoch);



	name.hash = full_name_hash(parent, name.name, name.len);

	dentry = d_lookup(parent, &name);
@@ -256,6 +258,7 @@ static int fuse_direntplus_link(struct file *file, 
	}

	if (fc->readdirplus_auto)

		set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);

	dentry->d_time = epoch;

	fuse_change_entry_timeout(dentry, o);



	dput(dentry);