The interface to the operating system file i/o primitives. More...

#include "os0file.h"
#include "fil0fil.h"
#include "ha_prototypes.h"
#include "log0write.h"
#include "my_dbug.h"
#include "my_io.h"
#include "sql_const.h"
#include "srv0srv.h"
#include "srv0start.h"
#include "os0event.h"
#include "os0thread.h"
#include <errno.h>
#include <lz4.h>
#include "my_aes.h"
#include "my_rnd.h"
#include "mysql/service_mysql_keyring.h"
#include "mysqld.h"
#include <sys/types.h>
#include <zlib.h>
#include <ctime>
#include <functional>
#include <new>
#include <ostream>
#include <vector>

Classes
struct	Slot
	The asynchronous I/O context. More...

class	AIO
	The asynchronous i/o array structure. More...

class	AIOHandler
	Generic AIO Handler methods. More...

class	SyncFileIO
	Helper class for doing synchronous file IO. More...

class	SimulatedAIOHandler
	Simulated AIO handler for reaping IO requests. More...

Macros
#define	BUFFER_BLOCK_SIZE ((ulint)(UNIV_PAGE_SIZE * 1.3))
	Block buffer size. More...

#define	USE_FILE_LOCK

Typedefs
using	Blocks = std::vector< file::Block >
	For storing the allocated blocks. More...

Functions
bool	os_is_o_direct_supported ()
	Determine if O_DIRECT is supported. More...

bool	buf_flush_page_cleaner_is_active ()
	Checks if the page_cleaner is in active state. More...

std::ostream &	operator<< (std::ostream &out, const Slot &obj) noexcept

static bool	os_aio_validate ()
	Validates the consistency of the aio system. More...

static bool	os_file_handle_error (const char name, const char operation)
	Does error handling when a file operation fails. More...

dberr_t	os_file_punch_hole (os_file_t fh, os_offset_t off, os_offset_t len)
	Free storage space associated with a section of the file. More...

static bool	os_file_handle_error_no_exit (const char name, const char operation, bool on_error_silent)
	Does error handling when a file operation fails. More...

static dberr_t	os_file_io_complete (const IORequest &type, os_file_t fh, byte *buf, ulint src_len, os_offset_t offset, ulint len)
	Decompress after a read and punch a hole in the file if it was a write. More...

static dberr_t	os_aio_simulated_handler (ulint global_segment, fil_node_t m1, void m2, IORequest *type)
	Does simulated AIO. More...

static bool	os_file_can_delete (const char *name)
	Check the file type and determine if it can be deleted. More...

byte *	os_block_get_frame (const file::Block *block) noexcept
	Get the sector aligned frame pointer. More...

file::Block *	os_alloc_block () noexcept
	Allocate a page for sync IO. More...

void	os_free_block (file::Block *block) noexcept
	Free a page after sync IO. More...

ulint	os_file_compressed_page_size (const byte *buf)
	If it is a compressed page return the compressed page data + footer size. More...

ulint	os_file_original_page_size (const byte *buf)
	If it is a compressed page return the original page data + footer size. More...

byte *	os_file_compress_page (Compression compression, ulint block_size, byte src, ulint src_len, byte dst, ulint *dst_len)
	Compress a data page. More...

static bool	os_aio_validate_skip ()
	Validates the consistency the aio system some of the time. More...

static int	os_file_lock (int fd, const char *name)
	Obtain an exclusive lock on a file. More...

FILE *	os_file_create_tmpfile ()
	Create a temporary file. More...

void	os_file_read_string (FILE file, char str, ulint size)
	Rewind file to its start, read at most size - 1 bytes from it to str, and NUL-terminate str. More...

static bool	os_file_is_root (const char path, const char last_slash)
	Check if the path refers to the root of a drive using a pointer to the last directory separator that the caller has fixed. More...

static char *	os_file_get_parent_dir (const char *path)
	Return the parent directory component of a null-terminated path. More...

dberr_t	os_file_create_subdirs_if_needed (const char *path)
	Creates all missing subdirectories along the given path. More...

file::Block *	os_file_compress_page (IORequest &type, void &buf, ulint n)
	Allocate the buffer for IO on a transparently compressed table. More...

file::Block *	os_file_encrypt_page (const IORequest &type, void *&buf, ulint n)
	Encrypt a page content when write it to disk. More...

static file::Block *	os_file_encrypt_log (const IORequest &type, void &buf, byte &scratch, ulint n)
	Encrypt log blocks provided in first n bytes of buf. More...

static dberr_t	os_file_punch_hole_posix (os_file_t fh, os_offset_t off, os_offset_t len)
	Free storage space associated with a section of the file. More...

static ulint	os_file_get_last_error_low (bool report_all_errors, bool on_error_silent)
	Retrieves the last error number if an error occurs in a file io function. More...

static int	os_file_fsync_posix (os_file_t file)
	Wrapper to fsync(2)/fdatasync(2) that retries the call on some errors. More...

static void	os_parent_dir_fsync_posix (const char *path)
	fsync the parent directory of a path. More...

static bool	os_file_status_posix (const char path, bool exists, os_file_type_t *type)
	Check the existence and type of the given file. More...

static bool	os_file_exists_posix (const char *path)
	Check the existence and usefulness of a given path. More...

bool	os_file_flush_func (os_file_t file)
	NOTE! Use the corresponding macro os_file_flush(), not directly this function! Flushes the write buffers of a given file to the disk. More...

bool	os_file_create_directory (const char *pathname, bool fail_if_exists)
	This function attempts to create a directory named pathname. More...

bool	os_file_scan_directory (const char *path, os_dir_cbk_t scan_cbk, bool is_drop)
	This function scans the contents of a directory and invokes the callback for each entry. More...

pfs_os_file_t	os_file_create_func (const char name, ulint create_mode, ulint purpose, ulint type, bool read_only, bool success)
	NOTE! Use the corresponding macro os_file_create(), not directly this function! Opens an existing file or creates a new. More...

pfs_os_file_t	os_file_create_simple_no_error_handling_func (const char name, ulint create_mode, ulint access_type, bool read_only, mode_t umask, bool success)
	NOTE! Use the corresponding macro os_file_create_simple_no_error_handling(), not directly this function! A simple function to open or create a file. More...

bool	os_file_delete_if_exists_func (const char name, bool exist)
	Deletes a file if it exists. More...

bool	os_file_delete_func (const char *name)
	Deletes a file. More...

bool	os_file_rename_func (const char oldpath, const char newpath)
	NOTE! Use the corresponding macro os_file_rename(), not directly this function! Renames a file (can also move it to another directory). More...

bool	os_file_close_func (os_file_t file)
	NOTE! Use the corresponding macro os_file_close(), not directly this function! Closes a file handle. More...

os_offset_t	os_file_get_size (pfs_os_file_t file)
	Gets a file size. More...

os_file_size_t	os_file_get_size (const char *filename)
	Gets a file size. More...

static dberr_t	os_get_free_space_posix (const char *path, uint64_t &free_space)
	Get available free space on disk. More...

static dberr_t	os_file_get_status_posix (const char path, os_file_stat_t stat_info, struct stat *statinfo, bool check_rw_perm, bool read_only)
	This function returns information about the specified file. More...

static bool	os_file_truncate_posix (const char *pathname, pfs_os_file_t file, os_offset_t size)
	Truncates a file to a specified size in bytes. More...

bool	os_file_set_eof (FILE *file)
	Truncates a file at its current position. More...

void	os_aio_simulated_put_read_threads_to_sleep ()
	This function can be called if one wants to post a batch of reads and prefers an i/o-handler thread to handle them all at once later. More...

static ssize_t	os_file_io (const IORequest &in_type, os_file_t file, void buf, ulint n, os_offset_t offset, dberr_t err, const file::Block *e_block)
	Does a synchronous read or write depending upon the type specified In case of partial reads/writes the function tries NUM_RETRIES_ON_PARTIAL_IO times to read/write the complete data. More...

static ssize_t	os_file_pwrite (IORequest &type, os_file_t file, const byte buf, ulint n, os_offset_t offset, dberr_t err, const file::Block *e_block)
	Does a synchronous write operation in Posix. More...

static dberr_t	os_file_write_page (IORequest &type, const char name, os_file_t file, const byte buf, os_offset_t offset, ulint n, const file::Block *e_block)
	Requests a synchronous write operation. More...

static ssize_t	os_file_pread (IORequest &type, os_file_t file, void buf, ulint n, os_offset_t offset, dberr_t err)
	Does a synchronous read operation in Posix. More...

static dberr_t	os_file_read_page (IORequest &type, const char file_name, os_file_t file, void buf, os_offset_t offset, ulint n, ulint *o, bool exit_on_err)
	Requests a synchronous positioned read operation. More...

ulint	os_file_get_last_error (bool report_all_errors)
	Retrieves the last error number if an error occurs in a file io function. More...

static bool	os_file_handle_error_cond_exit (const char name, const char operation, bool should_exit, bool on_error_silent)
	Does error handling when a file operation fails. More...

void	os_file_set_nocache (int fd, const char file_name, const char operation_name)
	Tries to disable OS caching on an opened file descriptor. More...

bool	os_file_set_size_fast (const char *name, pfs_os_file_t pfs_file, os_offset_t offset, os_offset_t size, bool flush)
	Allocate a block to file using fallocate from the given offset if fallocate is supported. More...

bool	os_file_set_size (const char *name, pfs_os_file_t file, os_offset_t offset, os_offset_t size, bool flush)
	Write the specified number of zeros to a file from specific offset. More...

bool	os_file_truncate (const char *pathname, pfs_os_file_t file, os_offset_t size)
	Truncates a file to a specified size in bytes. More...

bool	os_file_seek (const char *pathname, os_file_t file, os_offset_t offset)
	Set read/write position of a file handle to specific offset. More...

dberr_t	os_file_read_func (IORequest &type, const char file_name, os_file_t file, void buf, os_offset_t offset, ulint n)
	NOTE! Use the corresponding macro os_file_read_first_page(), not directly this function! Requests a synchronous read operation of page 0 of IBD file. More...

dberr_t	os_file_read_first_page_func (IORequest &type, const char file_name, os_file_t file, void buf, ulint n)
	NOTE! Use the corresponding macro os_file_read_first_page(), not directly this function! Requests a synchronous read operation of page 0 of IBD file. More...

static dberr_t	os_file_copy_read_write (os_file_t src_file, os_offset_t src_offset, os_file_t dest_file, os_offset_t dest_offset, uint size)
	copy data from one file to another file using read, write. More...

dberr_t	os_file_copy_func (os_file_t src_file, os_offset_t src_offset, os_file_t dest_file, os_offset_t dest_offset, uint size)
	Copy data from one file to another file. More...

dberr_t	os_file_read_no_error_handling_func (IORequest &type, const char file_name, os_file_t file, void buf, os_offset_t offset, ulint n, ulint *o)
	NOTE! Use the corresponding macro os_file_read_no_error_handling(), not directly this function! Requests a synchronous positioned read operation. More...

dberr_t	os_file_write_func (IORequest &type, const char name, os_file_t file, const void buf, os_offset_t offset, ulint n)
	NOTE! Use the corresponding macro os_file_write(), not directly this function! Requests a synchronous write operation. More...

bool	os_file_status (const char path, bool exists, os_file_type_t *type)
	Check the existence and type of a given path. More...

bool	os_file_exists (const char *path)
	Check the existence and usefulness of a given path. More...

bool	os_is_sparse_file_supported (pfs_os_file_t fh)
	Check if the file system supports sparse files. More...

dberr_t	os_get_free_space (const char *path, uint64_t &free_space)
	Get available free space on disk. More...

dberr_t	os_file_get_status (const char path, os_file_stat_t stat_info, bool check_rw_perm, bool read_only)
	This function returns information about the specified file. More...

dberr_t	os_file_write_zeros (pfs_os_file_t file, const char *name, ulint page_size, os_offset_t start, ulint len)
	Fill the pages with NULs. More...

bool	os_file_check_mode (const char *name, bool read_only)
	Check if a file can be opened in read-write mode. More...

dberr_t	os_aio_handler (ulint segment, fil_node_t m1, void m2, IORequest *request)
	Waits for an AIO operation to complete. More...

static void	io_handler_thread (ulint segment)
	I/o-handler thread function. More...

void	os_create_block_cache ()
	Creates and initializes block_cache. More...

bool	os_aio_init (ulint n_readers, ulint n_writers)
	Initializes the asynchronous io system. More...

void	os_aio_start_threads ()
	Starts one thread for each segment created in os_aio_init. More...

void	os_aio_free ()
	Frees the asynchronous io system. More...

void	os_aio_wake_all_threads_at_shutdown ()
	Wakes up all async i/o threads so that they know to exit themselves in shutdown. More...

void	os_aio_wait_until_no_pending_writes ()
	Waits until there are no pending writes in AIO::s_writes. More...

void	os_aio_simulated_wake_handler_threads ()
	Wakes up simulated aio i/o-handler threads if they have something to do. More...

dberr_t	os_aio_func (IORequest &type, AIO_mode aio_mode, const char name, pfs_os_file_t file, void buf, os_offset_t offset, ulint n, bool read_only, fil_node_t m1, void m2)
	NOTE! Use the corresponding macro os_aio(), not directly this function! Requests an asynchronous i/o operation. More...

void	os_aio_print (FILE *file)
	Prints info of the aio arrays. More...

void	os_aio_refresh_stats ()
	Refreshes the statistics used to print per-second averages. More...

bool	os_aio_all_slots_free ()
	Checks that all slots in the system have been freed, that is, there are no pending io operations. More...

void	os_aio_print_pending_io (FILE *file)
	Prints all pending IO. More...

void	os_file_set_umask (mode_t umask)
	Set the global file create umask. More...

dberr_t	os_file_write_retry (IORequest &type, const char name, pfs_os_file_t file, const void buf, os_offset_t offset, ulint n)
	This is a wrapper function for the os_file_write() function call. More...

Variables
unsigned long long	os_fsync_threshold = 0

static const ulint	IO_IBUF_SEGMENT = 0
	Insert buffer segment id. More...

static const ulint	NUM_RETRIES_ON_PARTIAL_IO = 10
	Number of retries for partial I/O's. More...

static Blocks *	block_cache
	Block collection. More...

static const size_t	MAX_BLOCKS = 128
	Number of blocks to allocate for sync read/writes. More...

static ulint	os_io_ptr_align = UNIV_SECTOR_SIZE
	Disk sector size of aligning write buffer for DIRECT_IO. More...

static mode_t	os_innodb_umask = S_IRUSR \| S_IWUSR \| S_IRGRP \| S_IWGRP
	This specifies the file permissions InnoDB uses when it creates files in Unix; the value of os_innodb_umask is initialized in ha_innodb.cc to my_umask. More...

static const ulint	OS_AIO_MERGE_N_CONSECUTIVE = 64
	In simulated aio, merge at most this many consecutive i/os. More...

static os_event_t *	os_aio_segment_wait_events = nullptr
	Array of events used in simulated AIO. More...

static ulint	os_aio_n_segments = ULINT_UNDEFINED
	Number of asynchronous I/O segments. More...

static bool	os_aio_recommend_sleep_for_read_threads = false
	If the following is true, read i/o handler threads try to wait until a batch of new read requests have been posted. More...

ulint	os_n_file_reads = 0

static ulint	os_bytes_read_since_printout = 0

ulint	os_n_file_writes = 0

ulint	os_n_fsyncs = 0

static ulint	os_n_file_reads_old = 0

static ulint	os_n_file_writes_old = 0

static ulint	os_n_fsyncs_old = 0

std::atomic< ulint >	os_n_pending_writes {0}
	Number of pending write operations. More...

std::atomic< ulint >	os_n_pending_reads {0}
	Number of pending read operations. More...

static std::chrono::steady_clock::time_point	os_last_printout

bool	os_has_said_disk_full = false

uint	page_zip_level
	Default Zip compression level. More...

Detailed Description

The interface to the operating system file i/o primitives.

Created 10/21/1995 Heikki Tuuri

Macro Definition Documentation

◆ BUFFER_BLOCK_SIZE

#define BUFFER_BLOCK_SIZE ((ulint)(UNIV_PAGE_SIZE * 1.3))

Block buffer size.

◆ USE_FILE_LOCK

#define USE_FILE_LOCK

Typedef Documentation

◆ Blocks

using Blocks = std::vector<file::Block>

For storing the allocated blocks.

Function Documentation

◆ buf_flush_page_cleaner_is_active()

bool buf_flush_page_cleaner_is_active ( )

Checks if the page_cleaner is in active state.

◆ io_handler_thread()

static void io_handler_thread ( ulint segment )

static

I/o-handler thread function.

Parameters

[in] segment The AIO segment the thread will work on

◆ operator<<()

std::ostream & operator<<	(	std::ostream &	out,
		const Slot &	obj
	)

inlinenoexcept

◆ os_aio_all_slots_free()

bool os_aio_all_slots_free ( )

Checks that all slots in the system have been freed, that is, there are no pending io operations.

Returns: true if all free

◆ os_aio_free()

void os_aio_free ( )

Frees the asynchronous io system.

◆ os_aio_func()

dberr_t os_aio_func	(	IORequest &	type,
		AIO_mode	aio_mode,
		const char *	name,
		pfs_os_file_t	file,
		void *	buf,
		os_offset_t	offset,
		ulint	n,
		bool	read_only,
		fil_node_t *	m1,
		void *	m2
	)

NOTE! Use the corresponding macro os_aio(), not directly this function! Requests an asynchronous i/o operation.

Parameters

[in]	type	IO request context
[in]	aio_mode	IO mode
[in]	name	Name of the file or path as NUL terminated string
[in]	file	Open file handle
[out]	buf	buffer where to read
[in]	offset	file offset where to read
[in]	n	how many bytes to read or write; this must not cross a file boundary; in AIO this must be a block size multiple
[in]	read_only	if true read only mode checks are enforced
[in,out]	m1	Message for the AIO handler, (can be used to identify a completed AIO operation); ignored if mode is OS_AIO_SYNC
[in,out]	m2	message for the AIO handler (can be used to identify a completed AIO operation); ignored if mode is OS_AIO_SYNC

Returns: DB_SUCCESS or error code

◆ os_aio_handler()

dberr_t os_aio_handler	(	ulint	segment,
		fil_node_t **	m1,
		void **	m2,
		IORequest *	request
	)

Waits for an AIO operation to complete.

This function is used to wait the for completed requests. The AIO array of pending requests is divided into segments. The thread specifies which segment or slot it wants to wait for. NOTE: this function will also take care of freeing the AIO slot, therefore no other thread is allowed to do the freeing!

Parameters

[in]	segment	The number of the segment in the AIO arrays to wait for; segment 0 is the ibuf I/O thread, then follow the non-ibuf read threads, and as the last are the non-ibuf write threads
[out]	m1	the messages passed with the AIO request; note that also in the case where the AIO operation failed, these output parameters are valid and can be used to restart the operation, for example
[out]	m2	callback message
[out]	request	OS_FILE_WRITE or ..._READ

Returns: DB_SUCCESS or error code

◆ os_aio_init()

bool os_aio_init	(	ulint	n_readers,
		ulint	n_writers
	)

Initializes the asynchronous io system.

Creates an array for ibuf i/o (if not in read-only mode). Also creates one array each for read and write where each array is divided logically into n_readers and n_writers respectively. The caller must create an i/o handler thread for each segment in these arrays by calling os_aio_start_threads().

Parameters

[in]	n_readers	number of reader threads
[in]	n_writers	number of writer threads

◆ os_aio_print()

void os_aio_print ( FILE * file )

Prints info of the aio arrays.

Parameters

[in,out] file file where to print

◆ os_aio_print_pending_io()

void os_aio_print_pending_io ( FILE * file )

Prints all pending IO.

Parameters

[in] file File where to print

◆ os_aio_refresh_stats()

void os_aio_refresh_stats ( )

Refreshes the statistics used to print per-second averages.

◆ os_aio_simulated_handler()

static dberr_t os_aio_simulated_handler	(	ulint	global_segment,
		fil_node_t **	m1,
		void **	m2,
		IORequest *	type
	)

static

Does simulated AIO.

This function should be called by an i/o-handler thread.

Parameters

[in]	global_segment	The number of the segment in the aio arrays to await for; segment 0 is the ibuf i/o thread, then follow the non-ibuf read threads, and as the last are the non-ibuf write threads
[out]	m1	the messages passed with the AIO request; note that also in the case where the AIO operation failed, these output parameters are valid and can be used to restart the operation, for example
[out]	m2	Callback argument
[in]	type	IO context

Returns: DB_SUCCESS or error code

Found a slot that has already completed its IO

◆ os_aio_simulated_put_read_threads_to_sleep()

void os_aio_simulated_put_read_threads_to_sleep ( )

This function can be called if one wants to post a batch of reads and prefers an i/o-handler thread to handle them all at once later.

You must call os_aio_simulated_wake_handler_threads later to ensure the threads are not left sleeping!

◆ os_aio_simulated_wake_handler_threads()

void os_aio_simulated_wake_handler_threads ( )

Wakes up simulated aio i/o-handler threads if they have something to do.

◆ os_aio_start_threads()

void os_aio_start_threads ( )

Starts one thread for each segment created in os_aio_init.

◆ os_aio_validate()

static bool os_aio_validate ( )

static

Validates the consistency of the aio system.

Validates the consistency the aio system.

Returns: true if ok

◆ os_aio_validate_skip()

static bool os_aio_validate_skip ( )

static

Validates the consistency the aio system some of the time.

Returns: true if ok or the check was skipped

Try os_aio_validate() every this many times

The os_aio_validate() call skip counter. Use a signed type because of the race condition below.

◆ os_aio_wait_until_no_pending_writes()

void os_aio_wait_until_no_pending_writes ( )

Waits until there are no pending writes in AIO::s_writes.

Waits until there are no pending writes in os_aio_write_array.

There can be other, synchronous, pending writes.

◆ os_aio_wake_all_threads_at_shutdown()

void os_aio_wake_all_threads_at_shutdown ( )

Wakes up all async i/o threads so that they know to exit themselves in shutdown.

◆ os_alloc_block()

file::Block * os_alloc_block ( )

noexcept

Allocate a page for sync IO.

Returns: pointer to page

◆ os_block_get_frame()

byte * os_block_get_frame ( const file::Block * block )

noexcept

Get the sector aligned frame pointer.

Parameters

[in] block the memory block containing the page frame.

Returns: the sector aligned frame pointer.

◆ os_create_block_cache()

void os_create_block_cache ( )

Creates and initializes block_cache.

Creates array of MAX_BLOCKS and allocates the memory in each block to hold BUFFER_BLOCK_SIZE of data.

This function is called by InnoDB during srv_start(). It is also called by MEB while applying the redo logs on TDE tablespaces, the "Blocks" allocated in this block_cache are used to hold the decrypted page data.

◆ os_file_can_delete()

static bool os_file_can_delete ( const char * name )

static

Check the file type and determine if it can be deleted.

Parameters

[in] name Filename/Path to check

Returns: true if it's a file or a symlink and can be deleted

◆ os_file_check_mode()

bool os_file_check_mode	(	const char *	name,
		bool	read_only
	)

Check if a file can be opened in read-write mode.

Parameters

[in]	name	filename to check
[in]	read_only	true if check for read-only mode only

Return values

true	if file can be opened in the specified mode (rw or ro); or file does not exist
false	if file exists and can't be opened in the specified mode

◆ os_file_close_func()

bool os_file_close_func ( os_file_t file )

NOTE! Use the corresponding macro os_file_close(), not directly this function! Closes a file handle.

In case of error, error number can be retrieved with os_file_get_last_error.

Parameters

[in] file Handle to a file

Returns: true if success

◆ os_file_compress_page() [1/2]

byte * os_file_compress_page	(	Compression	compression,
		ulint	block_size,
		byte *	src,
		ulint	src_len,
		byte *	dst,
		ulint *	dst_len
	)

Compress a data page.

Parameters

[in]	compression	Compression algorithm
[in]	block_size	File system block size
[in]	src	Source contents to compress
[in]	src_len	Length in bytes of the source
[out]	dst	Compressed page contents
[out]	dst_len	Length in bytes of dst contents

Returns: buffer data, dst_len will have the length of the data

◆ os_file_compress_page() [2/2]

file::Block * os_file_compress_page	(	IORequest &	type,
		void *&	buf,
		ulint *	n
	)

Allocate the buffer for IO on a transparently compressed table.

Parameters

[in]	type	IO flags
[out]	buf	buffer to read or write
[in,out]	n	number of bytes to read/write, starting from offset

Returns: pointer to allocated page, compressed data is written to the offset that is aligned on the disk sector size

◆ os_file_compressed_page_size()

ulint os_file_compressed_page_size ( const byte * buf )

If it is a compressed page return the compressed page data + footer size.

Parameters

[in] buf Buffer to check, must include header + 10 bytes

Returns: ULINT_UNDEFINED if the page is not a compressed page or length of the compressed data (including footer) if it is a compressed page

◆ os_file_copy_func()

dberr_t os_file_copy_func	(	os_file_t	src_file,
		os_offset_t	src_offset,
		os_file_t	dest_file,
		os_offset_t	dest_offset,
		uint	size
	)

Copy data from one file to another file.

Data is read/written at current file offset.

Parameters

[in]	src_file	file handle to copy from
[in]	src_offset	offset to copy from
[in]	dest_file	file handle to copy to
[in]	dest_offset	offset to copy to
[in]	size	number of bytes to copy

Returns: DB_SUCCESS if successful

◆ os_file_copy_read_write()

static dberr_t os_file_copy_read_write	(	os_file_t	src_file,
		os_offset_t	src_offset,
		os_file_t	dest_file,
		os_offset_t	dest_offset,
		uint	size
	)

static

copy data from one file to another file using read, write.

Parameters

[in]	src_file	file handle to copy from
[in]	src_offset	offset to copy from
[in]	dest_file	file handle to copy to
[in]	dest_offset	offset to copy to
[in]	size	number of bytes to copy

Returns: DB_SUCCESS if successful

◆ os_file_create_directory()

bool os_file_create_directory	(	const char *	pathname,
		bool	fail_if_exists
	)

This function attempts to create a directory named pathname.

The new directory gets default permissions. On Unix the permissions are (0770 & ~umask). If the directory exists already, nothing is done and the call succeeds, unless the fail_if_exists arguments is true. If another error occurs, such as a permission error, this does not crash, but reports the error and returns false.

Parameters

[in]	pathname	directory name as null-terminated string
[in]	fail_if_exists	if true, pre-existing directory is treated as an error.

Returns: true if call succeeds, false on error

◆ os_file_create_func()

pfs_os_file_t os_file_create_func	(	const char *	name,
		ulint	create_mode,
		ulint	purpose,
		ulint	type,
		bool	read_only,
		bool *	success
	)

NOTE! Use the corresponding macro os_file_create(), not directly this function! Opens an existing file or creates a new.

Parameters

[in]	name	name of the file or path as a null-terminated string
[in]	create_mode	create mode
[in]	purpose	OS_FILE_AIO, if asynchronous, non-buffered I/O is desired, OS_FILE_NORMAL, if any normal file; NOTE that it also depends on type, os_aio_.. and srv_.. variables whether we really use async I/O or unbuffered I/O: look in the function source code for the exact rules
[in]	type	OS_DATA_FILE, OS_LOG_FILE etc.
[in]	read_only	if true read only mode checks are enforced
[in]	success	true if succeeded

Returns: own: handle to the file, not defined if error, error number can be retrieved with os_file_get_last_error

◆ os_file_create_simple_no_error_handling_func()

pfs_os_file_t os_file_create_simple_no_error_handling_func	(	const char *	name,
		ulint	create_mode,
		ulint	access_type,
		bool	read_only,
		mode_t	umask,
		bool *	success
	)

NOTE! Use the corresponding macro os_file_create_simple_no_error_handling(), not directly this function! A simple function to open or create a file.

Parameters

[in]	name	name of the file or path as a null-terminated string
[in]	create_mode	create mode
[in]	access_type	OS_FILE_READ_ONLY, OS_FILE_READ_WRITE, or OS_FILE_READ_ALLOW_DELETE; the last option is used by a backup program reading the file
[in]	read_only	if true read only mode checks are enforced
[in]	umask	UNIX access permission to be set when creating a file. Use os_umask_default to use global default umask.
[out]	success	true if succeeded

Returns: own: handle to the file, not defined if error, error number can be retrieved with os_file_get_last_error

◆ os_file_create_subdirs_if_needed()

dberr_t os_file_create_subdirs_if_needed ( const char * path )

Creates all missing subdirectories along the given path.

Create all missing subdirectories along the given path.

Parameters

[in] path Path name

Returns: DB_SUCCESS if OK, otherwise error code.

◆ os_file_create_tmpfile()

FILE * os_file_create_tmpfile ( )

Create a temporary file.

This function is like tmpfile(3). It will create the file in the MySQL server configuration parameter (–tmpdir).

Returns: temporary file handle, or NULL on error

◆ os_file_delete_func()

bool os_file_delete_func ( const char * name )

Deletes a file.

The file has to be closed before calling this.

Parameters

[in] name file path as a null-terminated string

Returns: true if success

◆ os_file_delete_if_exists_func()

bool os_file_delete_if_exists_func	(	const char *	name,
		bool *	exist
	)

Deletes a file if it exists.

The file has to be closed before calling this.

Parameters

[in]	name	file path as a null-terminated string
[out]	exist	indicate if file pre-exist

Returns: true if success

◆ os_file_encrypt_log()

static file::Block * os_file_encrypt_log	(	const IORequest &	type,
		void *&	buf,
		byte *&	scratch,
		ulint	n
	)

static

Encrypt log blocks provided in first n bytes of buf.

If encryption is successful then buf will be repointed to the encrypted redo log of length n. If encryption fails then buf is not modified. The encrypted redo log will be stored in a newly allocated block returned from the function or in a newly allocated memory pointed by scratch. The caller takes ownership of the returned block and memory pointed by scratch, and when the buf is no longer needed, it should free the block using os_free_block(block) and scratch memory by using ut::aligned_free(scratch).

Parameters

[in]	type	IO flags
[in,out]	buf	before the call should contain unencrypted data, after the call will point to encrypted data, or to the original unencrypted data on failure
[in,out]	scratch	if not null contains the buf, and should be freed using ut::aligned_free
[in]	n	number of bytes in buf (encryption does not change the length)

Returns: if not null, then it's the block which contain the buf, and should be freed using os_free_block(block).

◆ os_file_encrypt_page()

file::Block * os_file_encrypt_page	(	const IORequest &	type,
		void *&	buf,
		ulint	n
	)

Encrypt a page content when write it to disk.

Parameters

[in]	type	IO flags
[out]	buf	buffer to read or write
[in]	n	number of bytes to read/write, starting from offset

Returns: pointer to the encrypted page

◆ os_file_exists()

bool os_file_exists ( const char * path )

Check the existence and usefulness of a given path.

Parameters

[in] path path name

Return values

true	if the path exists and can be used
false	if the path does not exist or if the path is unusable to get to a possibly existing file or directory.

◆ os_file_exists_posix()

static bool os_file_exists_posix ( const char * path )

static

Check the existence and usefulness of a given path.

Parameters

[in] path path name

Return values

true	if the path exists and can be used
false	if the path does not exist or if the path is unusable to get to a possibly existing file or directory.

◆ os_file_flush_func()

bool os_file_flush_func ( os_file_t file )

NOTE! Use the corresponding macro os_file_flush(), not directly this function! Flushes the write buffers of a given file to the disk.

Parameters

[in] file handle to a file

Returns: true if success

◆ os_file_fsync_posix()

static int os_file_fsync_posix ( os_file_t file )

static

Wrapper to fsync(2)/fdatasync(2) that retries the call on some errors.

Returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. srv_use_fdatasync determines whether fsync or fdatasync will be used. (true -> fdatasync)

Parameters

[in] file open file handle

Returns: 0 if success, -1 otherwise

◆ os_file_get_last_error()

ulint os_file_get_last_error ( bool report_all_errors )

Retrieves the last error number if an error occurs in a file io function.

The number should be retrieved before any other OS calls (because they may overwrite the error number). If the number is not known to this program, the OS error number + 100 is returned.

Parameters

[in] report_all_errors true if we want an error message printed for all errors

Returns: error number, or OS error number + 100

◆ os_file_get_last_error_low()

static ulint os_file_get_last_error_low	(	bool	report_all_errors,
		bool	on_error_silent
	)

static

Retrieves the last error number if an error occurs in a file io function.

The number should be retrieved before any other OS calls (because they may overwrite the error number). If the number is not known to this program, the OS error number + 100 is returned.

Parameters

[in]	report_all_errors	true if we want an error message printed of all errors
[in]	on_error_silent	true then don't print any diagnostic to the log

Returns: error number, or OS error number + 100

◆ os_file_get_parent_dir()

static char * os_file_get_parent_dir ( const char * path )

static

Return the parent directory component of a null-terminated path.

Return a new buffer containing the string up to, but not including, the final component of the path. The path returned will not contain a trailing separator. Do not return a root path, return NULL instead. The final component trimmed off may be a filename or a directory name. If the final component is the only component of the path, return NULL. It is the caller's responsibility to free the returned string after it is no longer needed.

Parameters

[in] path Path name

Returns: own: parent directory of the path

◆ os_file_get_size() [1/2]

os_file_size_t os_file_get_size ( const char * filename )

Gets a file size.

Parameters

[in] filename Full path to the filename to check

Returns: file size if OK, else set m_total_size to ~0 and m_alloc_size to errno.

◆ os_file_get_size() [2/2]

os_offset_t os_file_get_size ( pfs_os_file_t file )

Gets a file size.

Parameters

[in] file Handle to a file

Returns: file size, or (os_offset_t) -1 on failure

◆ os_file_get_status()

dberr_t os_file_get_status	(	const char *	path,
		os_file_stat_t *	stat_info,
		bool	check_rw_perm,
		bool	read_only
	)

This function returns information about the specified file.

Parameters

[in]	path	pathname of the file
[out]	stat_info	information of a file in a directory
[in]	check_rw_perm	for testing whether the file can be opened in RW mode
[in]	read_only	true if file is opened in read-only mode

Returns: DB_SUCCESS if all OK

◆ os_file_get_status_posix()

static dberr_t os_file_get_status_posix	(	const char *	path,
		os_file_stat_t *	stat_info,
		struct stat *	statinfo,
		bool	check_rw_perm,
		bool	read_only
	)

static

This function returns information about the specified file.

Parameters

[in]	path	pathname of the file
[out]	stat_info	information of a file in a directory
[in,out]	statinfo	information of a file in a directory
[in]	check_rw_perm	for testing whether the file can be opened in RW mode
[in]	read_only	if true read only mode checks are enforced

Returns: DB_SUCCESS if all OK

◆ os_file_handle_error()

static bool os_file_handle_error	(	const char *	name,
		const char *	operation
	)

static

Does error handling when a file operation fails.

Parameters

[in]	name	File name or NULL
[in]	operation	Name of operation e.g., "read", "write"

Returns: true if we should retry the operation

◆ os_file_handle_error_cond_exit()

static bool os_file_handle_error_cond_exit	(	const char *	name,
		const char *	operation,
		bool	should_exit,
		bool	on_error_silent
	)

static

Does error handling when a file operation fails.

Conditionally exits (calling srv_fatal_error()) based on should_exit value and the error type, if should_exit is true then on_error_silent is ignored.

Parameters

[in]	name	name of a file or NULL
[in]	operation	operation
[in]	should_exit	call srv_fatal_error() on an unknown error, if this parameter is true
[in]	on_error_silent	if true then don't print any message to the log iff it is an unknown non-fatal error

Returns: true if we should retry the operation

◆ os_file_handle_error_no_exit()

static bool os_file_handle_error_no_exit	(	const char *	name,
		const char *	operation,
		bool	on_error_silent
	)

static

Does error handling when a file operation fails.

Parameters

[in]	name	File name or NULL
[in]	operation	Name of operation e.g., "read", "write"
[in]	on_error_silent	if true then don't print any message to the log.

Returns: true if we should retry the operation

◆ os_file_io()

static ssize_t os_file_io	(	const IORequest &	in_type,
		os_file_t	file,
		void *	buf,
		ulint	n,
		os_offset_t	offset,
		dberr_t *	err,
		const file::Block *	e_block
	)

static

Does a synchronous read or write depending upon the type specified In case of partial reads/writes the function tries NUM_RETRIES_ON_PARTIAL_IO times to read/write the complete data.

Parameters

[in]	in_type	IO flags
[in]	file	handle to an open file
[out]	buf	buffer where to read
[in]	offset	file offset from the start where to read
[in]	n	number of bytes to read, starting from offset
[out]	err	DB_SUCCESS or error code
[in]	e_block	encrypted block or nullptr.

Returns: number of bytes read/written, -1 if error

◆ os_file_io_complete()

static dberr_t os_file_io_complete	(	const IORequest &	type,
		os_file_t	fh,
		byte *	buf,
		ulint	src_len,
		os_offset_t	offset,
		ulint	len
	)

static

Decompress after a read and punch a hole in the file if it was a write.

Parameters

[in]	type	IO context
[in]	fh	Open file handle
[in,out]	buf	Buffer to transform
[in]	src_len	Length of the buffer before compression
[in]	offset	file offset from the start where to read
[in]	len	Compressed buffer length for write and size of buf len for read

Returns: DB_SUCCESS or error code

◆ os_file_is_root()

static bool os_file_is_root	(	const char *	path,
		const char *	last_slash
	)

inlinestatic

Check if the path refers to the root of a drive using a pointer to the last directory separator that the caller has fixed.

Parameters

[in]	path	path name
[in]	last_slash	last directory separator in the path

Returns: true if this path is a drive root, false if not

◆ os_file_lock()

static int os_file_lock	(	int	fd,
		const char *	name
	)

static

Obtain an exclusive lock on a file.

Parameters

[in]	fd	file descriptor
[in]	name	file name

Returns: 0 on success

◆ os_file_original_page_size()

ulint os_file_original_page_size ( const byte * buf )

If it is a compressed page return the original page data + footer size.

Parameters

[in] buf Buffer to check, must include header + 10 bytes

Returns: ULINT_UNDEFINED if the page is not a compressed page or length of the original data + footer if it is a compressed page

◆ os_file_pread()

static ssize_t os_file_pread	(	IORequest &	type,
		os_file_t	file,
		void *	buf,
		ulint	n,
		os_offset_t	offset,
		dberr_t *	err
	)

static

Does a synchronous read operation in Posix.

Parameters

[in]	type	IO flags
[in]	file	handle to an open file
[out]	buf	buffer where to read
[in]	offset	file offset from the start where to read
[in]	n	number of bytes to read, starting from offset
[out]	err	DB_SUCCESS or error code

Returns: number of bytes read, -1 if error

◆ os_file_punch_hole()

dberr_t os_file_punch_hole	(	os_file_t	fh,
		os_offset_t	off,
		os_offset_t	len
	)

Free storage space associated with a section of the file.

Parameters

[in]	fh	Open file handle
[in]	off	Starting offset (SEEK_SET)
[in]	len	Size of the hole

Returns: DB_SUCCESS or error code

◆ os_file_punch_hole_posix()

static dberr_t os_file_punch_hole_posix	(	os_file_t	fh,
		os_offset_t	off,
		os_offset_t	len
	)

static

Free storage space associated with a section of the file.

Parameters

[in]	fh	Open file handle
[in]	off	Starting offset (SEEK_SET)
[in]	len	Size of the hole

Returns: DB_SUCCESS or error code

◆ os_file_pwrite()

static ssize_t os_file_pwrite	(	IORequest &	type,
		os_file_t	file,
		const byte *	buf,
		ulint	n,
		os_offset_t	offset,
		dberr_t *	err,
		const file::Block *	e_block
	)

static

Does a synchronous write operation in Posix.

Parameters

[in]	type	IO context
[in]	file	handle to an open file
[out]	buf	buffer from which to write
[in]	n	number of bytes to read, starting from offset
[in]	offset	file offset from the start where to read
[out]	err	DB_SUCCESS or error code
[in]	e_block	encrypted block or nullptr.

Returns: number of bytes written, -1 if error

◆ os_file_read_first_page_func()

dberr_t os_file_read_first_page_func	(	IORequest &	type,
		const char *	file_name,
		os_file_t	file,
		void *	buf,
		ulint	n
	)

NOTE! Use the corresponding macro os_file_read_first_page(), not directly this function! Requests a synchronous read operation of page 0 of IBD file.

Parameters

[in]	type	IO request context
[in]	file_name	file name
[in]	file	Open file handle
[out]	buf	buffer where to read
[in]	n	number of bytes to read

Returns: DB_SUCCESS if request was successful, DB_IO_ERROR on failure

◆ os_file_read_func()

dberr_t os_file_read_func	(	IORequest &	type,
		const char *	file_name,
		os_file_t	file,
		void *	buf,
		os_offset_t	offset,
		ulint	n
	)

NOTE! Use the corresponding macro os_file_read_first_page(), not directly this function! Requests a synchronous read operation of page 0 of IBD file.

Parameters

[in]	type	IO request context
[in]	file_name	file name
[in]	file	Open file handle
[out]	buf	buffer where to read
[in]	offset	file offset where to read
[in]	n	number of bytes to read

Returns: DB_SUCCESS if request was successful, DB_IO_ERROR on failure

◆ os_file_read_no_error_handling_func()

dberr_t os_file_read_no_error_handling_func	(	IORequest &	type,
		const char *	file_name,
		os_file_t	file,
		void *	buf,
		os_offset_t	offset,
		ulint	n,
		ulint *	o
	)

NOTE! Use the corresponding macro os_file_read_no_error_handling(), not directly this function! Requests a synchronous positioned read operation.

This function does not do any error handling. In case of error it returns false.

Parameters

[in]	type	IO request context
[in]	file_name	file name
[in]	file	Open file handle
[out]	buf	buffer where to read
[in]	offset	file offset where to read
[in]	n	number of bytes to read
[out]	o	number of bytes actually read

Returns: DB_SUCCESS or error code

◆ os_file_read_page()

static dberr_t os_file_read_page	(	IORequest &	type,
		const char *	file_name,
		os_file_t	file,
		void *	buf,
		os_offset_t	offset,
		ulint	n,
		ulint *	o,
		bool	exit_on_err
	)

static

Requests a synchronous positioned read operation.

Returns: DB_SUCCESS if request was successful, false if fail

Parameters

[in]	type	IO flags
[in]	file_name	file name
[in]	file	handle to an open file
[out]	buf	buffer where to read
[in]	offset	file offset from the start where to read
[in]	n	number of bytes to read, starting from offset
[out]	o	number of bytes actually read
[in]	exit_on_err	if true then exit on error

Returns: DB_SUCCESS or error code

The read will succeed but decompress can fail for various reasons.

◆ os_file_read_string()

void os_file_read_string	(	FILE *	file,
		char *	str,
		ulint	size
	)

Rewind file to its start, read at most size - 1 bytes from it to str, and NUL-terminate str.

All errors are silently ignored. This function is mostly meant to be used with temporary files.

Parameters

[in,out]	file	File to read from
[in,out]	str	Buffer where to read
[in]	size	Size of buffer

◆ os_file_rename_func()

bool os_file_rename_func	(	const char *	oldpath,
		const char *	newpath
	)

NOTE! Use the corresponding macro os_file_rename(), not directly this function! Renames a file (can also move it to another directory).

It is safest that the file is closed before calling this function.

Parameters

[in]	oldpath	old file path as a null-terminated string
[in]	newpath	new file path

Returns: true if success

◆ os_file_scan_directory()

bool os_file_scan_directory	(	const char *	path,
		os_dir_cbk_t	scan_cbk,
		bool	is_drop
	)

This function scans the contents of a directory and invokes the callback for each entry.

Parameters

[in]	path	directory name as null-terminated string
[in]	scan_cbk	use callback to be called for each entry
[in]	is_drop	attempt to drop the directory after scan

Returns: true if call succeeds, false on error

◆ os_file_seek()

bool os_file_seek	(	const char *	pathname,
		os_file_t	file,
		os_offset_t	offset
	)

Set read/write position of a file handle to specific offset.

Parameters

[in]	pathname	file path
[in]	file	file handle
[in]	offset	read/write offset

Returns: true if success

◆ os_file_set_eof()

bool os_file_set_eof ( FILE * file )

Truncates a file at its current position.

Returns: true if success

Parameters

file	in: file to be truncated

◆ os_file_set_nocache()

void os_file_set_nocache	(	int	fd,
		const char *	file_name,
		const char *	operation_name
	)

Tries to disable OS caching on an opened file descriptor.

Parameters

[in]	fd	file descriptor to alter
[in]	file_name	file name, used in the diagnostic message
[in]	operation_name	"open" or "create"; used in the diagnostic message

◆ os_file_set_size()

bool os_file_set_size	(	const char *	name,
		pfs_os_file_t	file,
		os_offset_t	offset,
		os_offset_t	size,
		bool	flush
	)

Write the specified number of zeros to a file from specific offset.

Parameters

[in]	name	name of the file or path as a null-terminated string
[in]	file	handle to a file
[in]	offset	file offset
[in]	size	file size
[in]	flush	flush file content to disk

Returns: true if success

◆ os_file_set_size_fast()

bool os_file_set_size_fast	(	const char *	name,
		pfs_os_file_t	file,
		os_offset_t	offset,
		os_offset_t	size,
		bool	flush
	)

Allocate a block to file using fallocate from the given offset if fallocate is supported.

Falls back to the old slower method of writing zeros otherwise.

Parameters

[in]	name	name of the file
[in]	file	handle to the file
[in]	offset	file offset
[in]	size	file size
[in]	flush	flush file content to disk

Returns: true if success

◆ os_file_set_umask()

void os_file_set_umask ( mode_t umask )

Set the global file create umask.

This value is to be set once, at startup and never modified.

Parameters

[in] umask The umask to use for all InnoDB file creation.

◆ os_file_status()

bool os_file_status	(	const char *	path,
		bool *	exists,
		os_file_type_t *	type
	)

Check the existence and type of a given path.

Parameters

[in]	path	pathname of the file
[out]	exists	true if file exists
[out]	type	type of the file (if it exists)

Returns: true if call succeeded

◆ os_file_status_posix()

static bool os_file_status_posix	(	const char *	path,
		bool *	exists,
		os_file_type_t *	type
	)

static

Check the existence and type of the given file.

Parameters

[in]	path	path name of file
[out]	exists	true if the file exists
[out]	type	Type of the file, if it exists

Returns: true if call succeeded

◆ os_file_truncate()

bool os_file_truncate	(	const char *	pathname,
		pfs_os_file_t	file,
		os_offset_t	size
	)

Truncates a file to a specified size in bytes.

Do nothing if the size to preserve is greater or equal to the current size of the file.

Parameters

[in]	pathname	file path
[in]	file	file to be truncated
[in]	size	size to preserve in bytes

Returns: true if success

◆ os_file_truncate_posix()

static bool os_file_truncate_posix	(	const char *	pathname,
		pfs_os_file_t	file,
		os_offset_t	size
	)

static

Truncates a file to a specified size in bytes.

Do nothing if the size to preserve is greater or equal to the current size of the file.

Parameters

[in]	pathname	file path
[in]	file	file to be truncated
[in]	size	size to preserve in bytes

Returns: true if success

◆ os_file_write_func()

dberr_t os_file_write_func	(	IORequest &	type,
		const char *	name,
		os_file_t	file,
		const void *	buf,
		os_offset_t	offset,
		ulint	n
	)

NOTE! Use the corresponding macro os_file_write(), not directly this function! Requests a synchronous write operation.

Parameters

[in,out]	type	IO request context
[in]	name	name of the file or path as a null-terminated string
[in]	file	Open file handle
[out]	buf	buffer where to read
[in]	offset	file offset where to read
[in]	n	number of bytes to read

Returns: DB_SUCCESS if request was successful

◆ os_file_write_page()

static dberr_t os_file_write_page	(	IORequest &	type,
		const char *	name,
		os_file_t	file,
		const byte *	buf,
		os_offset_t	offset,
		ulint	n,
		const file::Block *	e_block
	)

static

Requests a synchronous write operation.

Parameters

[in]	type	IO flags
[in]	name	name of the file or path as a null-terminated string
[in]	file	handle to an open file
[out]	buf	buffer from which to write
[in]	offset	file offset from the start where to read
[in]	n	number of bytes to read, starting from offset
[in]	e_block	encrypted block or nullptr.

Returns: DB_SUCCESS if request was successful, false if fail

◆ os_file_write_retry()

dberr_t os_file_write_retry	(	IORequest &	type,
		const char *	name,
		pfs_os_file_t	file,
		const void *	buf,
		os_offset_t	offset,
		ulint	n
	)

This is a wrapper function for the os_file_write() function call.

The purpose of this wrapper function is to retry on i/o error. On I/O error (perhaps because of disk full situation) keep retrying the write operation till it succeeds.

Parameters

[in]	type	IO flags
[in]	name	name of the file or path as a null-terminated string
[in]	file	handle to an open file
[out]	buf	buffer from which to write
[in]	offset	file offset from the start where to read
[in]	n	number of bytes to read, starting from offset

Returns: DB_SUCCESS if request was successful, false if fail

◆ os_file_write_zeros()

dberr_t os_file_write_zeros	(	pfs_os_file_t	file,
		const char *	name,
		ulint	page_size,
		os_offset_t	start,
		ulint	len
	)

Fill the pages with NULs.

Parameters

[in]	file	File handle
[in]	name	File name
[in]	page_size	physical page size
[in]	start	Offset from the start of the file in bytes
[in]	len	Length in bytes

Returns: DB_SUCCESS or error code

◆ os_free_block()

void os_free_block ( file::Block * block )

noexcept

Free a page after sync IO.

Parameters

[in,out] block The block to free/release

◆ os_get_free_space()

dberr_t os_get_free_space	(	const char *	path,
		uint64_t &	free_space
	)

Get available free space on disk.

Parameters

[in]	path	pathname of a directory or file in disk
[out]	free_space	free space available in bytes

Returns: DB_SUCCESS if all OK

◆ os_get_free_space_posix()

static dberr_t os_get_free_space_posix	(	const char *	path,
		uint64_t &	free_space
	)

static

Get available free space on disk.

Parameters

[in]	path	pathname of a directory or file in disk
[out]	free_space	free space available in bytes

Returns: DB_SUCCESS if all OK

◆ os_is_o_direct_supported()

bool os_is_o_direct_supported ( )

Determine if O_DIRECT is supported.

Return values

true	if O_DIRECT is supported.
false	if O_DIRECT is not supported.

◆ os_is_sparse_file_supported()

bool os_is_sparse_file_supported ( pfs_os_file_t fh )

Check if the file system supports sparse files.

Warning: On POSIX systems we try and punch a hole from offset 0 to the system configured page size. This should only be called on an empty file.

Note: On Windows we use the name and on Unices we use the file handle.

Parameters

[in] fh File handle for the file - if opened

Returns: true if the file system supports sparse files

◆ os_parent_dir_fsync_posix()

static void os_parent_dir_fsync_posix ( const char * path )

static

fsync the parent directory of a path.

Useful following rename, unlink, etc..

Parameters

[in] path path of file

if there is no parent dir in the path, then the real parent is either the current directory, or the root directory

Using fsync even when –innodb_use_fdatasync=ON since this operation is not very frequent, but WSL1 does not support fdatasync on directories.

Variable Documentation

◆ block_cache

Blocks* block_cache

static

Block collection.

◆ IO_IBUF_SEGMENT

const ulint IO_IBUF_SEGMENT = 0

static

Insert buffer segment id.

◆ MAX_BLOCKS

const size_t MAX_BLOCKS = 128

static

Number of blocks to allocate for sync read/writes.

◆ NUM_RETRIES_ON_PARTIAL_IO

const ulint NUM_RETRIES_ON_PARTIAL_IO = 10

static

Number of retries for partial I/O's.

◆ OS_AIO_MERGE_N_CONSECUTIVE

const ulint OS_AIO_MERGE_N_CONSECUTIVE = 64

static

In simulated aio, merge at most this many consecutive i/os.

◆ os_aio_n_segments

ulint os_aio_n_segments = ULINT_UNDEFINED

static

Number of asynchronous I/O segments.

Set by os_aio_init().

◆ os_aio_recommend_sleep_for_read_threads

bool os_aio_recommend_sleep_for_read_threads = false

static

If the following is true, read i/o handler threads try to wait until a batch of new read requests have been posted.

◆ os_aio_segment_wait_events

os_event_t* os_aio_segment_wait_events = nullptr

static

Array of events used in simulated AIO.

◆ os_bytes_read_since_printout

ulint os_bytes_read_since_printout = 0

static

◆ os_fsync_threshold

unsigned long long os_fsync_threshold = 0

◆ os_has_said_disk_full

bool os_has_said_disk_full = false

◆ os_innodb_umask

mode_t os_innodb_umask = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP

static

This specifies the file permissions InnoDB uses when it creates files in Unix; the value of os_innodb_umask is initialized in ha_innodb.cc to my_umask.

It is a global value and can't be modified once it is set.

◆ os_io_ptr_align

ulint os_io_ptr_align = UNIV_SECTOR_SIZE

static

Disk sector size of aligning write buffer for DIRECT_IO.

◆ os_last_printout

std::chrono::steady_clock::time_point os_last_printout

static

◆ os_n_file_reads

ulint os_n_file_reads = 0

◆ os_n_file_reads_old

ulint os_n_file_reads_old = 0

static

◆ os_n_file_writes

ulint os_n_file_writes = 0

◆ os_n_file_writes_old

ulint os_n_file_writes_old = 0

static

◆ os_n_fsyncs

ulint os_n_fsyncs = 0

◆ os_n_fsyncs_old

ulint os_n_fsyncs_old = 0

static

◆ os_n_pending_reads

std::atomic<ulint> os_n_pending_reads {0}

Number of pending read operations.

◆ os_n_pending_writes

std::atomic<ulint> os_n_pending_writes {0}

Number of pending write operations.

◆ page_zip_level

uint page_zip_level

extern

Default Zip compression level.

Classes

Macros

Typedefs

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ BUFFER_BLOCK_SIZE

◆ USE_FILE_LOCK

Typedef Documentation

◆ Blocks

Function Documentation

◆ buf_flush_page_cleaner_is_active()

◆ io_handler_thread()

◆ operator<<()

◆ os_aio_all_slots_free()

◆ os_aio_free()

◆ os_aio_func()

◆ os_aio_handler()

◆ os_aio_init()

◆ os_aio_print()

◆ os_aio_print_pending_io()

◆ os_aio_refresh_stats()

◆ os_aio_simulated_handler()

◆ os_aio_simulated_put_read_threads_to_sleep()

◆ os_aio_simulated_wake_handler_threads()

◆ os_aio_start_threads()

◆ os_aio_validate()

◆ os_aio_validate_skip()

◆ os_aio_wait_until_no_pending_writes()

◆ os_aio_wake_all_threads_at_shutdown()

◆ os_alloc_block()

◆ os_block_get_frame()

◆ os_create_block_cache()

◆ os_file_can_delete()

◆ os_file_check_mode()

◆ os_file_close_func()

◆ os_file_compress_page() [1/2]

◆ os_file_compress_page() [2/2]

◆ os_file_compressed_page_size()

◆ os_file_copy_func()

◆ os_file_copy_read_write()

◆ os_file_create_directory()

◆ os_file_create_func()

◆ os_file_create_simple_no_error_handling_func()

◆ os_file_create_subdirs_if_needed()

◆ os_file_create_tmpfile()

◆ os_file_delete_func()

◆ os_file_delete_if_exists_func()

◆ os_file_encrypt_log()

◆ os_file_encrypt_page()

◆ os_file_exists()

◆ os_file_exists_posix()

◆ os_file_flush_func()

◆ os_file_fsync_posix()

◆ os_file_get_last_error()

◆ os_file_get_last_error_low()

◆ os_file_get_parent_dir()

◆ os_file_get_size() [1/2]

◆ os_file_get_size() [2/2]

◆ os_file_get_status()

◆ os_file_get_status_posix()

◆ os_file_handle_error()

◆ os_file_handle_error_cond_exit()

◆ os_file_handle_error_no_exit()

◆ os_file_io()

◆ os_file_io_complete()

◆ os_file_is_root()

◆ os_file_lock()

◆ os_file_original_page_size()

◆ os_file_pread()

◆ os_file_punch_hole()

◆ os_file_punch_hole_posix()

◆ os_file_pwrite()

◆ os_file_read_first_page_func()

◆ os_file_read_func()

◆ os_file_read_no_error_handling_func()

◆ os_file_read_page()

◆ os_file_read_string()

◆ os_file_rename_func()