File Class Reference

File object to represent a file in the autotier filesystem. More...

#include <file.hpp>

Collaboration diagram for File:

Public Member Functions
	File (void)
	Construct a new empty File object. More...
	File (fs::path full_path, std::shared_ptr< rocksdb::DB > db, Tier *tptr)
	Construct a new File object. More...
	File (const File &other)
	Copy construct a new File object. More...
	~File ()
	Destroy the File object Calls metadata.update(relative_path_.c_str(), db_) to store newly updated metadata in database after tiering. More...
void	update_db (void)
	Call Metadata::update() More...
void	calc_popularity (double period_seconds)
	Calculate new popularity value of file. y[n] = MULTIPLIER * x / DAMPING + (1.0 - 1.0 / DAMPING) * y[n-1] where x is file usage frequency. More...
fs::path	full_path (void) const
	Return full backend path to file via tier. More...
fs::path	relative_path (void) const
	Return path to file relative to the tier path and the filesystem mountpoint. More...
Tier *	tier_ptr (void) const
	Get the pointer to the tier currently holding this file. More...
double	popularity (void) const
	Get popularity in accesses per hour. More...
struct timeval	atime (void) const
	Get last access time of file. More...
ffd::Bytes	size (void) const
	Get size of file on disk in bytes. More...
void	pin (void)
	Set metadata_.pinned_. Keeps file in current tier.
bool	is_pinned (void) const
	Get metadata_.pinned_. Check if file is pinned. More...
void	transfer_to_tier (Tier *tptr)
	Update tier_ptr_ and metadata_.tier_path_ then call metadata_.update(). More...
void	overwrite_times (void) const
	Call utimes() on file path with the saved atime and mtime so they stay the same as before tiering. More...
void	change_path (const fs::path &new_path)
	Update database with new path. More...

Private Attributes
ffd::Bytes	size_
	Size of file on disk.
Tier *	tier_ptr_
	Pointer to Tier object representing the tier containing this file.
struct timeval	times_ [2]
	atime and mtime of the file. Used to overwrite changes from copying file.
time_t	atime_
	Just the atime of the file.
time_t	ctime_
	Just the ctime of the file.
fs::path	relative_path_
	Location of file relative to the tier and the filesystem mountpoint.
std::shared_ptr< rocksdb::DB >	db_
	Database storing metadata.
Metadata	metadata_
	Metadata of object retrieved from database.

Detailed Description

File object to represent a file in the autotier filesystem.

Constructor & Destructor Documentation

File() [1/3]

File::File

(

void

)

Construct a new empty File object.

File() [2/3]

File::File	(	fs::path	full_path,
		std::shared_ptr< rocksdb::DB >	db,
		Tier *	tptr
	)

Construct a new File object.

Parameters

full_path	Full backend path to file
db	Rocksdb database pointer
tptr	Pointer to tier in which file was found

File() [3/3]

File::File

(

const File &

other

)

Copy construct a new File object.

Parameters

other

~File()

File::~File

(

)

Destroy the File object Calls metadata.update(relative_path_.c_str(), db_) to store newly updated metadata in database after tiering.

Member Function Documentation

atime()

struct timeval File::atime

(

void

)

const

Get last access time of file.

Returns

struct timeval

calc_popularity()

void File::calc_popularity

(

double

period_seconds

)

Calculate new popularity value of file. y[n] = MULTIPLIER * x / DAMPING + (1.0 - 1.0 / DAMPING) * y[n-1] where x is file usage frequency.

Parameters

period_seconds

Period over which to calculate

change_path()

void File::change_path

(

const fs::path &

new_path

)

Update database with new path.

Parameters

new_path

full_path()

fs::path File::full_path

(

void

)

const

Return full backend path to file via tier.

Returns

fs::path Full backend path

is_pinned()

bool File::is_pinned

(

void

)

const

Get metadata_.pinned_. Check if file is pinned.

Returns

true File is pinned

false File is not pinned

overwrite_times()

void File::overwrite_times

(

void

)

const

Call utimes() on file path with the saved atime and mtime so they stay the same as before tiering.

popularity()

double File::popularity

(

void

)

const

Get popularity in accesses per hour.

Returns

double EMA of accesses per hour.

relative_path()

fs::path File::relative_path

(

void

)

const

Return path to file relative to the tier path and the filesystem mountpoint.

Returns

fs::path Relative path

size()

ffd::Bytes File::size

(

void

)

const

Get size of file on disk in bytes.

Returns

ffd::Bytes Size of file

tier_ptr()

Tier * File::tier_ptr

(

void

)

const

Get the pointer to the tier currently holding this file.

Returns

Tier* Tier holding this file

transfer_to_tier()

void File::transfer_to_tier

(

Tier *

tptr

)

Update tier_ptr_ and metadata_.tier_path_ then call metadata_.update().

Subtracts file size from old tier, updates tptr_ to new tier, adds file size to new tier, updates metadata.tier_path, then calls metadata.update() to update the db.

Parameters

tptr

New tier.

update_db()

void File::update_db

(

void

)

Call Metadata::update()

---

The documentation for this class was generated from the following files:

• src/incl/file.hpp
• src/impl/autotierfs/file.cpp