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260 lines
6 KiB
C
260 lines
6 KiB
C
![]() |
/*
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FUSE: Filesystem in Userspace
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Copyright (C) 2001-2018 Miklos Szeredi <miklos@szeredi.hu>
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This program can be distributed under the terms of the GNU GPL.
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See the file COPYING.
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*/
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#include "fuse_i.h"
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#include <linux/posix_acl.h>
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static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx)
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{
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struct fuse_conn *fc = get_fuse_conn(dir);
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struct fuse_inode *fi = get_fuse_inode(dir);
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if (!fc->do_readdirplus)
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return false;
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if (!fc->readdirplus_auto)
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return true;
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if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state))
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return true;
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if (ctx->pos == 0)
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return true;
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return false;
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}
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static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
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struct dir_context *ctx)
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{
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while (nbytes >= FUSE_NAME_OFFSET) {
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struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
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size_t reclen = FUSE_DIRENT_SIZE(dirent);
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if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
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return -EIO;
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if (reclen > nbytes)
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break;
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if (memchr(dirent->name, '/', dirent->namelen) != NULL)
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return -EIO;
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if (!dir_emit(ctx, dirent->name, dirent->namelen,
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dirent->ino, dirent->type))
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break;
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buf += reclen;
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nbytes -= reclen;
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ctx->pos = dirent->off;
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}
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return 0;
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}
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static int fuse_direntplus_link(struct file *file,
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struct fuse_direntplus *direntplus,
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u64 attr_version)
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{
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struct fuse_entry_out *o = &direntplus->entry_out;
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struct fuse_dirent *dirent = &direntplus->dirent;
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struct dentry *parent = file->f_path.dentry;
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struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);
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struct dentry *dentry;
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struct dentry *alias;
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struct inode *dir = d_inode(parent);
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struct fuse_conn *fc;
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struct inode *inode;
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DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
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if (!o->nodeid) {
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/*
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* Unlike in the case of fuse_lookup, zero nodeid does not mean
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* ENOENT. Instead, it only means the userspace filesystem did
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* not want to return attributes/handle for this entry.
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*
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* So do nothing.
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*/
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return 0;
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}
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if (name.name[0] == '.') {
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/*
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* We could potentially refresh the attributes of the directory
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* and its parent?
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*/
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if (name.len == 1)
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return 0;
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if (name.name[1] == '.' && name.len == 2)
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return 0;
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}
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if (invalid_nodeid(o->nodeid))
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return -EIO;
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if (!fuse_valid_type(o->attr.mode))
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return -EIO;
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fc = get_fuse_conn(dir);
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name.hash = full_name_hash(parent, name.name, name.len);
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dentry = d_lookup(parent, &name);
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if (!dentry) {
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retry:
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dentry = d_alloc_parallel(parent, &name, &wq);
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if (IS_ERR(dentry))
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return PTR_ERR(dentry);
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}
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if (!d_in_lookup(dentry)) {
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struct fuse_inode *fi;
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inode = d_inode(dentry);
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if (!inode ||
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get_node_id(inode) != o->nodeid ||
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((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
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d_invalidate(dentry);
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dput(dentry);
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goto retry;
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}
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if (is_bad_inode(inode)) {
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dput(dentry);
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return -EIO;
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}
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fi = get_fuse_inode(inode);
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spin_lock(&fc->lock);
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fi->nlookup++;
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spin_unlock(&fc->lock);
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forget_all_cached_acls(inode);
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fuse_change_attributes(inode, &o->attr,
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entry_attr_timeout(o),
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attr_version);
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/*
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* The other branch comes via fuse_iget()
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* which bumps nlookup inside
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*/
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} else {
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inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
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&o->attr, entry_attr_timeout(o),
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attr_version);
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if (!inode)
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inode = ERR_PTR(-ENOMEM);
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alias = d_splice_alias(inode, dentry);
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d_lookup_done(dentry);
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if (alias) {
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dput(dentry);
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dentry = alias;
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}
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if (IS_ERR(dentry))
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return PTR_ERR(dentry);
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}
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if (fc->readdirplus_auto)
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set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
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fuse_change_entry_timeout(dentry, o);
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dput(dentry);
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return 0;
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}
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static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
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struct dir_context *ctx, u64 attr_version)
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{
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struct fuse_direntplus *direntplus;
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struct fuse_dirent *dirent;
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size_t reclen;
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int over = 0;
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int ret;
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while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
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direntplus = (struct fuse_direntplus *) buf;
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dirent = &direntplus->dirent;
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reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
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if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
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return -EIO;
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if (reclen > nbytes)
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break;
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if (memchr(dirent->name, '/', dirent->namelen) != NULL)
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return -EIO;
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if (!over) {
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/* We fill entries into dstbuf only as much as
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it can hold. But we still continue iterating
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over remaining entries to link them. If not,
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we need to send a FORGET for each of those
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which we did not link.
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*/
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over = !dir_emit(ctx, dirent->name, dirent->namelen,
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dirent->ino, dirent->type);
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if (!over)
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ctx->pos = dirent->off;
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}
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buf += reclen;
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nbytes -= reclen;
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ret = fuse_direntplus_link(file, direntplus, attr_version);
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if (ret)
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fuse_force_forget(file, direntplus->entry_out.nodeid);
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}
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return 0;
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}
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int fuse_readdir(struct file *file, struct dir_context *ctx)
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{
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int plus, err;
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size_t nbytes;
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struct page *page;
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struct inode *inode = file_inode(file);
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struct fuse_conn *fc = get_fuse_conn(inode);
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struct fuse_req *req;
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u64 attr_version = 0;
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bool locked;
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if (is_bad_inode(inode))
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return -EIO;
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req = fuse_get_req(fc, 1);
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if (IS_ERR(req))
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return PTR_ERR(req);
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page = alloc_page(GFP_KERNEL);
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if (!page) {
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fuse_put_request(fc, req);
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return -ENOMEM;
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}
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plus = fuse_use_readdirplus(inode, ctx);
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req->out.argpages = 1;
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req->num_pages = 1;
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req->pages[0] = page;
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req->page_descs[0].length = PAGE_SIZE;
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if (plus) {
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attr_version = fuse_get_attr_version(fc);
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fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
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FUSE_READDIRPLUS);
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} else {
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fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
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FUSE_READDIR);
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}
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locked = fuse_lock_inode(inode);
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fuse_request_send(fc, req);
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fuse_unlock_inode(inode, locked);
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nbytes = req->out.args[0].size;
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err = req->out.h.error;
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fuse_put_request(fc, req);
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if (!err) {
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if (plus) {
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err = parse_dirplusfile(page_address(page), nbytes,
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file, ctx, attr_version);
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} else {
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err = parse_dirfile(page_address(page), nbytes, file,
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ctx);
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}
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}
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__free_page(page);
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fuse_invalidate_atime(inode);
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return err;
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}
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