Directory entry. More...

Collaboration diagram for Directory Entry:

Typedefs
typedef void	dump_refstat_receiver_t(int depth, const dentry_t dentry, bool mountroot, void data)

Enumerations
enum	LastSegmentResolveFlag { RESOLVE_EXPECT_FILE = 1 << 0 , RESOLVE_EXPECT_DIR = 1 << 1 , RESOLVE_EXPECT_ANY_TYPE = RESOLVE_EXPECT_FILE \| RESOLVE_EXPECT_DIR , RESOLVE_SYMLINK_NOFOLLOW = 1 << 2 , RESOLVE_EXPECT_EXIST = 1 << 3 , RESOLVE_EXPECT_NONEXIST = 1 << 4 , RESOLVE_EXPECT_ANY_EXIST = RESOLVE_EXPECT_EXIST \| RESOLVE_EXPECT_NONEXIST }

Functions
	MOS_ENUM_FLAGS (LastSegmentResolveFlag, LastSegmentResolveFlags)
should_inline bool	path_is_absolute (mos::string_view path)
	Check if a path is absolute.
should_inline dentry_t *	dentry_parent (const dentry_t &dentry)
void	dentry_check_refstat (const dentry_t *dentry)
	Check the reference count of a dentry.
void	dentry_dump_refstat (const dentry_t dentry, dump_refstat_receiver_t receiver, void data)
dentry_t *	dentry_ref (dentry_t *dentry)
	Increment the reference count of a dentry.
dentry_t *	dentry_ref_up_to (dentry_t dentry, dentry_t root)
	Increment the reference count of a dentry up to a given dentry.
void	dentry_unref (dentry_t *dentry)
	Decrement the reference count of a dentry.
__nodiscard bool	dentry_unref_one_norelease (dentry_t *dentry)
	Decrease the refcount of ONE SINGLE dentry, including (if it's a mountpoint) the mountpoint dentry.
void	dentry_try_release (dentry_t *dentry)
void	dentry_attach (dentry_t d, inode_t inode)
	Attach an inode to a dentry.
void	dentry_detach (dentry_t *dentry)
	Detach the inode from a dentry.
PtrResult< dentry_t >	dentry_from_fd (fd_t fd)
	Get the dentry from a file descriptor.
PtrResult< dentry_t >	dentry_lookup_child (dentry_t *parent, mos::string_view name)
	Get a child dentry from a parent dentry.
PtrResult< dentry_t >	dentry_resolve (dentry_t starting_dir, dentry_t root_dir, mos::string_view path, LastSegmentResolveFlags flags)
	Lookup a path in the filesystem.
__nodiscard bool	dentry_mount (dentry_t mountpoint, dentry_t root, filesystem_t *fs)
	Mount a filesystem at a mountpoint.
__nodiscard dentry_t *	dentry_unmount (dentry_t *root)
	Unmount a filesystem at the mountpoint.
void	vfs_populate_listdir_buf (dentry_t dir, vfs_listdir_state_t state)
	List the contents of a directory.
std::optional< mos::string >	dentry_path (const dentry_t dentry, dentry_t root)
	Get the path of a dentry.

Detailed Description

Directory entry.

A dentry is a directory entry, it is a reference to an inode.

dentry cache policy: The function who references the dentry should be responsible for unrefing it.

All existing files' dentries have a reference count of 0 at the start. When a file is opened, the dentry will be referenced, and the reference count will be incremented by 1.

For all directories, the initial reference count is also 0, but when a directory is opened, the reference count will be incremented by 1.

When mounting a filesystem, the root dentry of the filesystem is inserted into the dentry cache, and will have a reference count of 1. The mountpoint itself will have its reference count incremented by 1.

For the root dentry ("/"), the reference count is 2, one for the mountpoint, and one for the dentry cache.

Typedef Documentation

◆ dump_refstat_receiver_t

typedef void dump_refstat_receiver_t(int depth, const dentry_t *dentry, bool mountroot, void *data)

Definition at line 78 of file dentry.hpp.

Enumeration Type Documentation

◆ LastSegmentResolveFlag

enum LastSegmentResolveFlag

Enumerator
RESOLVE_EXPECT_FILE
RESOLVE_EXPECT_DIR
RESOLVE_EXPECT_ANY_TYPE
RESOLVE_SYMLINK_NOFOLLOW
RESOLVE_EXPECT_EXIST
RESOLVE_EXPECT_NONEXIST
RESOLVE_EXPECT_ANY_EXIST

Definition at line 37 of file dentry.hpp.

Function Documentation

◆ MOS_ENUM_FLAGS()

MOS_ENUM_FLAGS	(	LastSegmentResolveFlag	,
		LastSegmentResolveFlags	)

◆ path_is_absolute()

should_inline bool path_is_absolute ( mos::string_view path )

Check if a path is absolute.

Parameters

path	The path to check

Returns: true if the path is absolute (starts with a '/'), false otherwise

Definition at line 62 of file dentry.hpp.

Referenced by dentry_resolve_to_parent(), vfs_chdirat(), vfs_fchmodat(), vfs_fstatat(), vfs_mkdir(), vfs_mount(), vfs_openat(), vfs_readlinkat(), vfs_rmdir(), vfs_symlink(), and vfs_unlinkat().

◆ dentry_parent()

should_inline dentry_t * dentry_parent ( const dentry_t & dentry )

Definition at line 67 of file dentry.hpp.

Referenced by cpio_i_iterate_dir(), dentry_mount(), dentry_path(), dentry_ref_up_to(), dentry_resolve_follow_symlink(), dentry_resolve_lastseg(), dentry_resolve_to_parent(), dentry_root_get_mountpoint(), dentry_unref(), sysfs_fops_release(), vfs_do_open(), vfs_generic_iterate_dir(), vfs_mkdir(), vfs_rmdir(), vfs_symlink(), and vfs_unlinkat().

◆ dentry_check_refstat()

void dentry_check_refstat ( const dentry_t * dentry )

Check the reference count of a dentry.

Parameters

dentry The dentry to check

Definition at line 110 of file dentry_utils.cpp.

Referenced by dentry_unref(), and vfs_unmount().

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◆ dentry_dump_refstat()

void dentry_dump_refstat	(	const dentry_t *	dentry,
		dump_refstat_receiver_t	receiver,
		void *	data )

◆ dentry_ref()

dentry_t * dentry_ref ( dentry_t * dentry )

Increment the reference count of a dentry.

Parameters

dentry The dentry to increment the reference count of

Returns: the dentry itself

Definition at line 16 of file dentry_utils.cpp.

Referenced by dentry_lookup_child(), dentry_mount(), dentry_ref_up_to(), dentry_resolve_lastseg(), dentry_resolve_to_parent(), memfd_create(), and memfd_init().

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◆ dentry_ref_up_to()

dentry_t * dentry_ref_up_to	(	dentry_t *	dentry,
		dentry_t *	root )

Increment the reference count of a dentry up to a given dentry.

Parameters

dentry	The dentry to increment the reference count of
root	The dentry to stop at

Returns: dentry_t* The dentry itself

Definition at line 26 of file dentry_utils.cpp.

Referenced by dentry_resolve_to_parent(), process_do_fork(), and process_new().

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◆ dentry_unref()

void dentry_unref ( dentry_t * dentry )

Decrement the reference count of a dentry.

Parameters

dentry The dentry to decrement the reference count of

Definition at line 159 of file dentry_utils.cpp.

Referenced by dentry_resolve(), dentry_resolve_follow_symlink(), dentry_resolve_lastseg(), dentry_resolve_to_parent(), dentry_unref(), ipc_server_close(), FsDir::on_closed(), FsFile::on_closed(), process_exit(), vfs_chdirat(), vfs_do_open(), vfs_fchmodat(), vfs_fstatat(), vfs_mkdir(), vfs_mount(), vfs_readlinkat(), vfs_rmdir(), vfs_symlink(), vfs_unlinkat(), and vfs_unmount().

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◆ dentry_unref_one_norelease()

__nodiscard bool dentry_unref_one_norelease ( dentry_t * dentry )

Decrease the refcount of ONE SINGLE dentry, including (if it's a mountpoint) the mountpoint dentry.

Parameters

dentry The dentry to decrease the refcount of

Returns: true if the refcount was decreased, false if the refcount was already 0

Definition at line 51 of file dentry_utils.cpp.

Referenced by dentry_resolve_lastseg(), dentry_resolve_to_parent(), dentry_unref(), and vfs_unmount().

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◆ dentry_try_release()

void dentry_try_release ( dentry_t * dentry )

Definition at line 147 of file dentry_utils.cpp.

Referenced by dentry_resolve_lastseg(), dentry_resolve_to_parent(), dentry_unref(), ipc_server_close(), and vfs_unlinkat().

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◆ dentry_attach()

void dentry_attach	(	dentry_t *	d,
		inode_t *	inode )

Attach an inode to a dentry.

Parameters

d	The dentry to attach the inode to
inode	The inode to attach

Definition at line 279 of file dentry.cpp.

Referenced by cpio_i_lookup(), cpio_mount(), ipc_server_close(), ipc_sysfs_create_server(), ipc_sysfs_lookup_ipc(), MOS_INIT(), sysfs_do_register(), sysfs_register_file(), tmpfs_fsop_mount(), tmpfs_i_hardlink(), tmpfs_i_rename(), tmpfs_mknod_impl(), userfs_fsop_mount(), userfs_iop_lookup(), userfs_iop_mkdir(), and userfs_iop_newfile().

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◆ dentry_detach()

void dentry_detach ( dentry_t * dentry )

Detach the inode from a dentry.

Parameters

dentry The dentry to detach the inode from

Definition at line 292 of file dentry.cpp.

Referenced by ipc_server_close(), memfd_file_release(), tmpfs_i_rename(), tmpfs_i_rmdir(), vfs_ipc_file_release(), and vfs_unlinkat().

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◆ dentry_from_fd()

PtrResult< dentry_t > dentry_from_fd ( fd_t fd )

Get the dentry from a file descriptor.

Parameters

fd	The file descriptor, there's a special case for AT_FDCWD, which corresponds to the process's current working directory

Returns: The dentry associated with the file descriptor, or NULL if the file descriptor is invalid

Definition at line 304 of file dentry.cpp.

Referenced by vfs_chdirat(), vfs_fchmodat(), vfs_fstatat(), vfs_getcwd(), vfs_mkdir(), vfs_mount(), vfs_openat(), vfs_readlinkat(), vfs_rmdir(), vfs_symlink(), and vfs_unlinkat().

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◆ dentry_lookup_child()

PtrResult< dentry_t > dentry_lookup_child	(	dentry_t *	parent,
		mos::string_view	name )

Get a child dentry from a parent dentry.

Parameters

parent	The parent dentry
name	The name of the child dentry

Returns: The child dentry, always non-NULL, even if the child dentry does not exist in the filesystem

Note: The returned dentry will have its reference count incremented, even if it does not exist.

Definition at line 328 of file dentry.cpp.

Referenced by dentry_resolve_lastseg(), and dentry_resolve_to_parent().

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◆ dentry_resolve()

PtrResult< dentry_t > dentry_resolve	(	dentry_t *	starting_dir,
		dentry_t *	root_dir,
		mos::string_view	path,
		LastSegmentResolveFlags	flags )

Lookup a path in the filesystem.

If the path is absolute, the base is ignored and the path starts from the root_dir If the path is relative, the base is used as the starting points

Parameters

starting_dir	The starting directory when resolving a [relative] path
root_dir	the root directory when resolving the path, the resolved path will not go above this directory
path	The path to resolve, can be absolute or relative
flags	Flags to control the behavior of the path resolution, see lastseg_resolve_flags_t

Returns: The parent directory (if such a parent exists) containing (or to contain) the last segment of the path, or NULL if any intermediate directory in the path does not exist.

Definition at line 371 of file dentry.cpp.

Referenced by vfs_chdirat(), vfs_do_open(), vfs_fchmodat(), vfs_fstatat(), vfs_mkdir(), vfs_mount(), vfs_readlinkat(), vfs_rmdir(), vfs_symlink(), vfs_unlinkat(), and vfs_unmount().

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◆ dentry_mount()

__nodiscard bool dentry_mount	(	dentry_t *	mountpoint,
		dentry_t *	root,
		filesystem_t *	fs )

Mount a filesystem at a mountpoint.

Parameters

mountpoint	The mountpoint
root	The root directory of the filesystem
fs	The filesystem to mount

Returns: true if the filesystem was mounted successfully, false otherwise

Definition at line 70 of file mount.cpp.

Referenced by vfs_mount().

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◆ dentry_unmount()

__nodiscard dentry_t * dentry_unmount ( dentry_t * root )

Unmount a filesystem at the mountpoint.

Returns: __nodiscard

Definition at line 100 of file mount.cpp.

Referenced by vfs_unmount().

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◆ vfs_populate_listdir_buf()

void vfs_populate_listdir_buf	(	dentry_t *	dir,
		vfs_listdir_state_t *	state )

List the contents of a directory.

Parameters

dir	The directory to list
state	The state of the directory iterator

Definition at line 416 of file dentry.cpp.

Referenced by vfs_list_dir().

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◆ dentry_path()

std::optional< mos::string > dentry_path	(	const dentry_t *	dentry,
		dentry_t *	root )

Get the path of a dentry.

Parameters

dentry	The dentry to get the path of
root	The root directory, the path will not go above this directory

Returns: mos::string String representation of the path

Definition at line 171 of file dentry_utils.cpp.

Referenced by cpio_i_lookup(), FsBaseFile::name(), vfs_getcwd(), and vfs_sysfs_mountpoints().

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Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

◆ dump_refstat_receiver_t

Enumeration Type Documentation

◆ LastSegmentResolveFlag

Function Documentation

◆ MOS_ENUM_FLAGS()

◆ path_is_absolute()

◆ dentry_parent()

◆ dentry_check_refstat()

◆ dentry_dump_refstat()

◆ dentry_ref()

◆ dentry_ref_up_to()

◆ dentry_unref()

◆ dentry_unref_one_norelease()

◆ dentry_try_release()

◆ dentry_attach()

◆ dentry_detach()

◆ dentry_from_fd()

◆ dentry_lookup_child()

◆ dentry_resolve()

◆ dentry_mount()

◆ dentry_unmount()

◆ vfs_populate_listdir_buf()

◆ dentry_path()