From d123d8e1833c5d854b56f2a7da17cafd0a901df8 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 28 Sep 2018 16:43:23 +0200 Subject: fuse: split out readdir.c Directory reading code is about to grow larger, so split it out from dir.c into a new source file. Signed-off-by: Miklos Szeredi --- fs/fuse/readdir.c | 259 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 259 insertions(+) create mode 100644 fs/fuse/readdir.c (limited to 'fs/fuse/readdir.c') diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c new file mode 100644 index 000000000000..3e100e00e21e --- /dev/null +++ b/fs/fuse/readdir.c @@ -0,0 +1,259 @@ +/* + FUSE: Filesystem in Userspace + Copyright (C) 2001-2018 Miklos Szeredi + + This program can be distributed under the terms of the GNU GPL. + See the file COPYING. +*/ + + +#include "fuse_i.h" +#include + +static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx) +{ + struct fuse_conn *fc = get_fuse_conn(dir); + struct fuse_inode *fi = get_fuse_inode(dir); + + if (!fc->do_readdirplus) + return false; + if (!fc->readdirplus_auto) + return true; + if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state)) + return true; + if (ctx->pos == 0) + return true; + return false; +} + +static int parse_dirfile(char *buf, size_t nbytes, struct file *file, + struct dir_context *ctx) +{ + while (nbytes >= FUSE_NAME_OFFSET) { + struct fuse_dirent *dirent = (struct fuse_dirent *) buf; + size_t reclen = FUSE_DIRENT_SIZE(dirent); + if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX) + return -EIO; + if (reclen > nbytes) + break; + if (memchr(dirent->name, '/', dirent->namelen) != NULL) + return -EIO; + + if (!dir_emit(ctx, dirent->name, dirent->namelen, + dirent->ino, dirent->type)) + break; + + buf += reclen; + nbytes -= reclen; + ctx->pos = dirent->off; + } + + return 0; +} + +static int fuse_direntplus_link(struct file *file, + struct fuse_direntplus *direntplus, + u64 attr_version) +{ + 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 = d_inode(parent); + struct fuse_conn *fc; + struct inode *inode; + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + + 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; + } + + if (invalid_nodeid(o->nodeid)) + return -EIO; + if (!fuse_valid_type(o->attr.mode)) + return -EIO; + + fc = get_fuse_conn(dir); + + name.hash = full_name_hash(parent, name.name, name.len); + dentry = d_lookup(parent, &name); + if (!dentry) { +retry: + dentry = d_alloc_parallel(parent, &name, &wq); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + } + if (!d_in_lookup(dentry)) { + struct fuse_inode *fi; + inode = d_inode(dentry); + if (!inode || + get_node_id(inode) != o->nodeid || + ((o->attr.mode ^ inode->i_mode) & S_IFMT)) { + d_invalidate(dentry); + dput(dentry); + goto retry; + } + if (is_bad_inode(inode)) { + dput(dentry); + return -EIO; + } + + fi = get_fuse_inode(inode); + spin_lock(&fc->lock); + fi->nlookup++; + spin_unlock(&fc->lock); + + forget_all_cached_acls(inode); + fuse_change_attributes(inode, &o->attr, + entry_attr_timeout(o), + attr_version); + /* + * The other branch comes via fuse_iget() + * which bumps nlookup inside + */ + } else { + inode = fuse_iget(dir->i_sb, o->nodeid, o->generation, + &o->attr, entry_attr_timeout(o), + attr_version); + if (!inode) + inode = ERR_PTR(-ENOMEM); + + alias = d_splice_alias(inode, dentry); + d_lookup_done(dentry); + if (alias) { + dput(dentry); + dentry = alias; + } + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + } + if (fc->readdirplus_auto) + set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state); + fuse_change_entry_timeout(dentry, o); + + dput(dentry); + return 0; +} + +static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file, + struct dir_context *ctx, 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 (memchr(dirent->name, '/', dirent->namelen) != NULL) + return -EIO; + + 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 = !dir_emit(ctx, dirent->name, dirent->namelen, + dirent->ino, dirent->type); + if (!over) + ctx->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; +} + +int fuse_readdir(struct file *file, struct dir_context *ctx) +{ + int plus, err; + size_t nbytes; + struct page *page; + struct inode *inode = file_inode(file); + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req; + u64 attr_version = 0; + bool locked; + + if (is_bad_inode(inode)) + return -EIO; + + req = fuse_get_req(fc, 1); + if (IS_ERR(req)) + return PTR_ERR(req); + + page = alloc_page(GFP_KERNEL); + if (!page) { + fuse_put_request(fc, req); + return -ENOMEM; + } + + plus = fuse_use_readdirplus(inode, ctx); + req->out.argpages = 1; + req->num_pages = 1; + req->pages[0] = page; + req->page_descs[0].length = PAGE_SIZE; + if (plus) { + attr_version = fuse_get_attr_version(fc); + fuse_read_fill(req, file, ctx->pos, PAGE_SIZE, + FUSE_READDIRPLUS); + } else { + fuse_read_fill(req, file, ctx->pos, PAGE_SIZE, + FUSE_READDIR); + } + locked = fuse_lock_inode(inode); + fuse_request_send(fc, req); + fuse_unlock_inode(inode, locked); + nbytes = req->out.args[0].size; + err = req->out.h.error; + fuse_put_request(fc, req); + if (!err) { + if (plus) { + err = parse_dirplusfile(page_address(page), nbytes, + file, ctx, attr_version); + } else { + err = parse_dirfile(page_address(page), nbytes, file, + ctx); + } + } + + __free_page(page); + fuse_invalidate_atime(inode); + return err; +} -- cgit v1.2.3