mirrors/ladybird
0
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2025-05-02 01:08:48 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

Kernel: Deemphasize inode identifiers

Browse source 
These APIs were clearly modeled after Ext2FS internals, and make perfect sense
in Ext2FS context. The new APIs are more generic, and map better to the
semantics exported to the userspace, where inode identifiers only appear in
stat() and readdir() output, but never in any input.

This will also hopefully reduce the potential for races (see commit c44b4d61f3).

Lastly, this makes it way more viable to implement a filesystem that only
synthesizes its inodes lazily when queried, and destroys them when they are no
longer in use. With inode identifiers being used to reference inodes, the only
choice for such a filesystem is to persist any inode it has given out the
identifier for, because it might be queried at any later time. With direct
references to inodes, the filesystem will know when the last reference is
dropped and the inode can be safely destroyed.
This commit is contained in:
Sergey Bugaev 2020-06-24 23:35:56 +03:00 • committed by Andreas Kling
parent c689be0dbc
commit df66c28479
Notes: sideshowbarker 2024-07-19 05:23:53 +09:00
12 changed files with 133 additions and 160 deletions
Download patch file Download diff file Expand all files Collapse all files

24
Kernel/FileSystem/VirtualFileSystem.cpp
View file

@ -137,15 +137,14 @@ bool VFS::mount_root(FS& file_system)
Mount mount { file_system, nullptr, root_mount_flags };
auto root_inode_id = mount.guest().fs()->root_inode();
auto root_inode = mount.guest().fs()->get_inode(root_inode_id);
auto root_inode = file_system.root_inode();
if (!root_inode->is_directory()) {
klog() << "VFS: root inode (" << String::format("%02u", root_inode_id.fsid()) << ":" << String::format("%08u", root_inode_id.index()) << ") for / is not a directory :(";
klog() << "VFS: root inode (" << String::format("%02u", file_system.fsid()) << ":" << String::format("%08u", root_inode->index()) << ") for / is not a directory :(";
return false;
}
m_root_inode = move(root_inode);
klog() << "VFS: mounted root from " << m_root_inode->fs().class_name() << " (" << static_cast<FileBackedFS&>(m_root_inode->fs()).file_description().absolute_path() << ")";
klog() << "VFS: mounted root from " << file_system.class_name() << " (" << static_cast<FileBackedFS&>(file_system).file_description().absolute_path() << ")";
m_mounts.append(move(mount));
return true;
@ -184,7 +183,8 @@ void VFS::traverse_directory_inode(Inode& dir_inode, Function<bool(const FS::Dir
resolved_inode = entry.inode;
// FIXME: This is now broken considering chroot and bind mounts.
if (dir_inode.identifier().is_root_inode() && !is_vfs_root(dir_inode.identifier()) && !strcmp(entry.name, "..")) {
bool is_root_inode = dir_inode.identifier() == dir_inode.fs().root_inode()->identifier();
if (is_root_inode && !is_vfs_root(dir_inode.identifier()) && !strcmp(entry.name, "..")) {
auto mount = find_mount_for_guest(entry.inode);
ASSERT(mount);
resolved_inode = mount->host();
@ -321,7 +321,7 @@ KResult VFS::mknod(StringView path, mode_t mode, dev_t dev, Custody& base)
LexicalPath p(path);
dbg() << "VFS::mknod: '" << p.basename() << "' mode=" << mode << " dev=" << dev << " in " << parent_inode.identifier();
return parent_inode.fs().create_inode(parent_inode.identifier(), p.basename(), mode, 0, dev, Process::current->uid(), Process::current->gid()).result();
return parent_inode.create_child(p.basename(), mode, dev, Process::current->uid(), Process::current->gid()).result();
}
KResultOr<NonnullRefPtr<FileDescription>> VFS::create(StringView path, int options, mode_t mode, Custody& parent_custody, Optional<UidAndGid> owner)
@ -347,7 +347,7 @@ KResultOr<NonnullRefPtr<FileDescription>> VFS::create(StringView path, int optio
#endif
uid_t uid = owner.has_value() ? owner.value().uid : Process::current->uid();
gid_t gid = owner.has_value() ? owner.value().gid : Process::current->gid();
auto inode_or_error = parent_inode.fs().create_inode(parent_inode.identifier(), p.basename(), mode, 0, 0, uid, gid);
auto inode_or_error = parent_inode.create_child(p.basename(), mode, 0, uid, gid);
if (inode_or_error.is_error())
return inode_or_error.error();
@ -386,7 +386,7 @@ KResult VFS::mkdir(StringView path, mode_t mode, Custody& base)
#ifdef VFS_DEBUG
dbg() << "VFS::mkdir: '" << p.basename() << "' in " << parent_inode.identifier();
#endif
return parent_inode.fs().create_directory(parent_inode.identifier(), p.basename(), mode, Process::current->uid(), Process::current->gid());
return parent_inode.create_child(p.basename(), S_IFDIR | mode, 0, Process::current->uid(), Process::current->gid()).result();
}
KResult VFS::access(StringView path, int mode, Custody& base)
@ -506,7 +506,7 @@ KResult VFS::rename(StringView old_path, StringView new_path, Custody& base)
return result;
}
auto result = new_parent_inode.add_child(old_inode.identifier(), new_basename, old_inode.mode());
auto result = new_parent_inode.add_child(old_inode, new_basename, old_inode.mode());
if (result.is_error())
return result;
@ -593,7 +593,7 @@ KResult VFS::link(StringView old_path, StringView new_path, Custody& base)
if (parent_custody->is_readonly())
return KResult(-EROFS);
return parent_inode.add_child(old_inode.identifier(), LexicalPath(new_path).basename(), old_inode.mode());
return parent_inode.add_child(old_inode, LexicalPath(new_path).basename(), old_inode.mode());
}
KResult VFS::unlink(StringView path, Custody& base)
@ -650,7 +650,7 @@ KResult VFS::symlink(StringView target, StringView linkpath, Custody& base)
LexicalPath p(linkpath);
dbg() << "VFS::symlink: '" << p.basename() << "' (-> '" << target << "') in " << parent_inode.identifier();
auto inode_or_error = parent_inode.fs().create_inode(parent_inode.identifier(), p.basename(), 0120644, 0, 0, Process::current->uid(), Process::current->gid());
auto inode_or_error = parent_inode.create_child(p.basename(), S_IFLNK | 0644, 0, Process::current->uid(), Process::current->gid());
if (inode_or_error.is_error())
return inode_or_error.error();
auto& inode = inode_or_error.value();
@ -709,7 +709,7 @@ RefPtr<Inode> VFS::get_inode(InodeIdentifier inode_id)
}
VFS::Mount::Mount(FS& guest_fs, Custody* host_custody, int flags)
: m_guest(guest_fs.root_inode())
: m_guest(guest_fs.root_inode()->identifier())
, m_guest_fs(guest_fs)
, m_host_custody(host_custody)
, m_flags(flags)