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authorMiklos Szeredi <mszeredi@redhat.com>2018-09-28 16:43:23 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2018-09-28 16:43:23 +0200
commitd123d8e1833c5d854b56f2a7da17cafd0a901df8 (patch)
treeb90ca45d76440931fd8853013246f8a7916d0ce8 /fs/fuse/readdir.c
parentbe2ff42c5d6ebc8552c82a7d1697afae30510ed9 (diff)
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 <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse/readdir.c')
-rw-r--r--fs/fuse/readdir.c259
1 files changed, 259 insertions, 0 deletions
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 <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU GPL.
+ See the file COPYING.
+*/
+
+
+#include "fuse_i.h"
+#include <linux/posix_acl.h>
+
+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;
+}