fuse: implement NFS-like readdirplus support
This patch implements readdirplus support in FUSE, similar to NFS.
The payload returned in the readdirplus call contains
'fuse_entry_out' structure thereby providing all the necessary inputs
for 'faking' a lookup() operation on the spot.
If the dentry and inode already existed (for e.g. in a re-run of ls -l)
then just the inode attributes timeout and dentry timeout are refreshed.
With a simple client->network->server implementation of a FUSE based
filesystem, the following performance observations were made:
Test: Performing a filesystem crawl over 20,000 files with
sh# time ls -lR /mnt
Without readdirplus:
Run 1: 18.1s
Run 2: 16.0s
Run 3: 16.2s
With readdirplus:
Run 1: 4.1s
Run 2: 3.8s
Run 3: 3.8s
The performance improvement is significant as it avoided 20,000 upcalls
calls (lookup). Cache consistency is no worse than what already is.
Signed-off-by: Anand V. Avati <avati@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index e83351a..05c3eec2 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -491,6 +491,25 @@
fuse_request_send_nowait_locked(fc, req);
}
+void fuse_force_forget(struct file *file, u64 nodeid)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_req *req;
+ struct fuse_forget_in inarg;
+
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.nlookup = 1;
+ req = fuse_get_req_nofail(fc, file);
+ req->in.h.opcode = FUSE_FORGET;
+ req->in.h.nodeid = nodeid;
+ req->in.numargs = 1;
+ req->in.args[0].size = sizeof(inarg);
+ req->in.args[0].value = &inarg;
+ req->isreply = 0;
+ fuse_request_send_nowait(fc, req);
+}
+
/*
* Lock the request. Up to the next unlock_request() there mustn't be
* anything that could cause a page-fault. If the request was already
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index b7c09f9..dcc1e52 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1155,6 +1155,143 @@
return 0;
}
+static int fuse_direntplus_link(struct file *file,
+ struct fuse_direntplus *direntplus,
+ u64 attr_version)
+{
+ int err;
+ struct fuse_entry_out *o = &direntplus->entry_out;
+ struct fuse_dirent *dirent = &direntplus->dirent;
+ struct dentry *parent = file->f_path.dentry;
+ struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);
+ struct dentry *dentry;
+ struct dentry *alias;
+ struct inode *dir = parent->d_inode;
+ struct fuse_conn *fc;
+ struct inode *inode;
+
+ if (!o->nodeid) {
+ /*
+ * Unlike in the case of fuse_lookup, zero nodeid does not mean
+ * ENOENT. Instead, it only means the userspace filesystem did
+ * not want to return attributes/handle for this entry.
+ *
+ * So do nothing.
+ */
+ return 0;
+ }
+
+ if (name.name[0] == '.') {
+ /*
+ * We could potentially refresh the attributes of the directory
+ * and its parent?
+ */
+ if (name.len == 1)
+ return 0;
+ if (name.name[1] == '.' && name.len == 2)
+ return 0;
+ }
+ fc = get_fuse_conn(dir);
+
+ name.hash = full_name_hash(name.name, name.len);
+ dentry = d_lookup(parent, &name);
+ if (dentry && dentry->d_inode) {
+ inode = dentry->d_inode;
+ if (get_node_id(inode) == o->nodeid) {
+ struct fuse_inode *fi;
+ fi = get_fuse_inode(inode);
+ spin_lock(&fc->lock);
+ fi->nlookup++;
+ spin_unlock(&fc->lock);
+
+ /*
+ * The other branch to 'found' comes via fuse_iget()
+ * which bumps nlookup inside
+ */
+ goto found;
+ }
+ err = d_invalidate(dentry);
+ if (err)
+ goto out;
+ dput(dentry);
+ dentry = NULL;
+ }
+
+ dentry = d_alloc(parent, &name);
+ err = -ENOMEM;
+ if (!dentry)
+ goto out;
+
+ inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
+ &o->attr, entry_attr_timeout(o), attr_version);
+ if (!inode)
+ goto out;
+
+ alias = d_materialise_unique(dentry, inode);
+ err = PTR_ERR(alias);
+ if (IS_ERR(alias))
+ goto out;
+ if (alias) {
+ dput(dentry);
+ dentry = alias;
+ }
+
+found:
+ fuse_change_attributes(inode, &o->attr, entry_attr_timeout(o),
+ attr_version);
+
+ fuse_change_entry_timeout(dentry, o);
+
+ err = 0;
+out:
+ if (dentry)
+ dput(dentry);
+ return err;
+}
+
+static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
+ void *dstbuf, filldir_t filldir, u64 attr_version)
+{
+ struct fuse_direntplus *direntplus;
+ struct fuse_dirent *dirent;
+ size_t reclen;
+ int over = 0;
+ int ret;
+
+ while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
+ direntplus = (struct fuse_direntplus *) buf;
+ dirent = &direntplus->dirent;
+ reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
+
+ if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
+ return -EIO;
+ if (reclen > nbytes)
+ break;
+
+ if (!over) {
+ /* We fill entries into dstbuf only as much as
+ it can hold. But we still continue iterating
+ over remaining entries to link them. If not,
+ we need to send a FORGET for each of those
+ which we did not link.
+ */
+ over = filldir(dstbuf, dirent->name, dirent->namelen,
+ file->f_pos, dirent->ino,
+ dirent->type);
+ file->f_pos = dirent->off;
+ }
+
+ buf += reclen;
+ nbytes -= reclen;
+
+ ret = fuse_direntplus_link(file, direntplus, attr_version);
+ if (ret)
+ fuse_force_forget(file, direntplus->entry_out.nodeid);
+ }
+
+ return 0;
+}
+
static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
{
int err;
@@ -1163,6 +1300,7 @@
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
+ u64 attr_version = 0;
if (is_bad_inode(inode))
return -EIO;
@@ -1179,14 +1317,28 @@
req->out.argpages = 1;
req->num_pages = 1;
req->pages[0] = page;
- fuse_read_fill(req, file, file->f_pos, PAGE_SIZE, FUSE_READDIR);
+ if (fc->do_readdirplus) {
+ attr_version = fuse_get_attr_version(fc);
+ fuse_read_fill(req, file, file->f_pos, PAGE_SIZE,
+ FUSE_READDIRPLUS);
+ } else {
+ fuse_read_fill(req, file, file->f_pos, PAGE_SIZE,
+ FUSE_READDIR);
+ }
fuse_request_send(fc, req);
nbytes = req->out.args[0].size;
err = req->out.h.error;
fuse_put_request(fc, req);
- if (!err)
- err = parse_dirfile(page_address(page), nbytes, file, dstbuf,
- filldir);
+ if (!err) {
+ if (fc->do_readdirplus) {
+ err = parse_dirplusfile(page_address(page), nbytes,
+ file, dstbuf, filldir,
+ attr_version);
+ } else {
+ err = parse_dirfile(page_address(page), nbytes, file,
+ dstbuf, filldir);
+ }
+ }
__free_page(page);
fuse_invalidate_attr(inode); /* atime changed */
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index e105a53..5c50553 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -487,6 +487,9 @@
/** Use enhanced/automatic page cache invalidation. */
unsigned auto_inval_data:1;
+ /** Does the filesystem support readdir-plus? */
+ unsigned do_readdirplus:1;
+
/** The number of requests waiting for completion */
atomic_t num_waiting;
@@ -578,6 +581,9 @@
struct fuse_forget_link *fuse_alloc_forget(void);
+/* Used by READDIRPLUS */
+void fuse_force_forget(struct file *file, u64 nodeid);
+
/**
* Initialize READ or READDIR request
*/
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 73ca6b7..6f7d574 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -863,6 +863,8 @@
fc->dont_mask = 1;
if (arg->flags & FUSE_AUTO_INVAL_DATA)
fc->auto_inval_data = 1;
+ if (arg->flags & FUSE_DO_READDIRPLUS)
+ fc->do_readdirplus = 1;
} else {
ra_pages = fc->max_read / PAGE_CACHE_SIZE;
fc->no_lock = 1;
@@ -889,7 +891,8 @@
arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
- FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA;
+ FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
+ FUSE_DO_READDIRPLUS;
req->in.h.opcode = FUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index d8c713e..5dc1fea 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -193,6 +193,7 @@
#define FUSE_FLOCK_LOCKS (1 << 10)
#define FUSE_HAS_IOCTL_DIR (1 << 11)
#define FUSE_AUTO_INVAL_DATA (1 << 12)
+#define FUSE_DO_READDIRPLUS (1 << 13)
/**
* CUSE INIT request/reply flags
@@ -299,6 +300,7 @@
FUSE_NOTIFY_REPLY = 41,
FUSE_BATCH_FORGET = 42,
FUSE_FALLOCATE = 43,
+ FUSE_READDIRPLUS = 44,
/* CUSE specific operations */
CUSE_INIT = 4096,
@@ -630,6 +632,16 @@
#define FUSE_DIRENT_SIZE(d) \
FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)
+struct fuse_direntplus {
+ struct fuse_entry_out entry_out;
+ struct fuse_dirent dirent;
+};
+
+#define FUSE_NAME_OFFSET_DIRENTPLUS \
+ offsetof(struct fuse_direntplus, dirent.name)
+#define FUSE_DIRENTPLUS_SIZE(d) \
+ FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET_DIRENTPLUS + (d)->dirent.namelen)
+
struct fuse_notify_inval_inode_out {
__u64 ino;
__s64 off;