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authorAnand V. Avati <avati@redhat.com>2012-08-19 08:53:23 -0400
committerMiklos Szeredi <mszeredi@suse.cz>2013-01-24 16:21:25 +0100
commit0b05b18381eea98c9c9ada95629bf659a88c9374 (patch)
treea6389eaffda03a2e28cb05be242e03ef839fcb91 /fs/fuse/dir.c
parentff7532ca2c631e7e96dcd305a967b610259dc0ea (diff)
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>
Diffstat (limited to 'fs/fuse/dir.c')
-rw-r--r--fs/fuse/dir.c160
1 files changed, 156 insertions, 4 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index b7c09f9eb40c..dcc1e522c7d4 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1155,6 +1155,143 @@ static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
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 @@ static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
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 @@ static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
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 */