Data Structures
struct	m0_dtm0_log_rec

struct	m0_be_dtm0_log

Enumerations
enum	m0_be_dtm0_log_credit_op { M0_DTML_CREATE, M0_DTML_SENT, M0_DTML_EXECUTED, M0_DTML_PERSISTENT, M0_DTML_PRUNE, M0_DTML_REDO }

Functions
M0_INTERNAL int	m0_be_dtm0_log_alloc (struct m0_be_dtm0_log **log)

M0_INTERNAL int	m0_be_dtm0_log_init (struct m0_be_dtm0_log log, struct m0_be_seg seg, struct m0_dtm0_clk_src *cs, bool is_plog)

M0_INTERNAL void	m0_be_dtm0_log_fini (struct m0_be_dtm0_log *log)

M0_INTERNAL void	m0_be_dtm0_log_free (struct m0_be_dtm0_log **log)

M0_INTERNAL void	m0_be_dtm0_log_credit (enum m0_be_dtm0_log_credit_op op, struct m0_dtm0_tx_desc txd, struct m0_buf payload, struct m0_be_seg seg, struct m0_dtm0_log_rec rec, struct m0_be_tx_credit *accum)

M0_INTERNAL int	m0_be_dtm0_log_create (struct m0_be_tx tx, struct m0_be_seg seg, struct m0_be_dtm0_log **out)

M0_INTERNAL void	m0_be_dtm0_log_destroy (struct m0_be_tx tx, struct m0_be_dtm0_log *log)

M0_INTERNAL int	m0_be_dtm0_log_update (struct m0_be_dtm0_log log, struct m0_be_tx tx, struct m0_dtm0_tx_desc txd, struct m0_buf payload)

M0_INTERNAL struct m0_dtm0_log_rec *	m0_be_dtm0_log_find (struct m0_be_dtm0_log log, const struct m0_dtm0_tid id)

M0_INTERNAL int	m0_be_dtm0_log_prune (struct m0_be_dtm0_log log, struct m0_be_tx tx, const struct m0_dtm0_tid *id)

M0_INTERNAL bool	m0_be_dtm0_plog_can_prune (struct m0_be_dtm0_log log, const struct m0_dtm0_tid id, struct m0_be_tx_credit *cred)

M0_INTERNAL int	m0_be_dtm0_plog_prune (struct m0_be_dtm0_log log, struct m0_be_tx tx, const struct m0_dtm0_tid *id)

M0_INTERNAL void	m0_be_dtm0_log_clear (struct m0_be_dtm0_log *log)

M0_INTERNAL int	m0_be_dtm0_volatile_log_insert (struct m0_be_dtm0_log log, struct m0_dtm0_log_rec rec)

M0_INTERNAL void	m0_be_dtm0_volatile_log_update (struct m0_be_dtm0_log log, struct m0_dtm0_log_rec rec)

M0_INTERNAL void	m0_be_dtm0_log_pmsg_post (struct m0_be_dtm0_log log, struct m0_fop fop)

Detailed Description

section describes the dtm0 log related enumerations and structures.

Enumeration Type Documentation

◆ m0_be_dtm0_log_credit_op

enum m0_be_dtm0_log_credit_op

m0_be_dtm0_log_credit_op enum

DTM0 persistent log is implemented on top of be modules and uses be_list for storing the log records. m0_be_dtm0_log_credit_op is an enumeration of the operation codes that can be specified to obtain credits for performing the corresponding operation related to dtm0_log.

Enumerator
M0_DTML_CREATE	m0_be_dtm0_log_create()
M0_DTML_SENT	m0_be_dtm0_log_update()
M0_DTML_EXECUTED	m0_be_dtm0_log_update()
M0_DTML_PERSISTENT	m0_be_dtm0_log_update()
M0_DTML_PRUNE	m0_be_dtm0_log_prune()
M0_DTML_REDO	m0_be_dtm0_log_update()

Definition at line 141 of file dtm0_log.h.

Function Documentation

◆ m0_be_dtm0_log_alloc()

M0_INTERNAL int m0_be_dtm0_log_alloc ( struct m0_be_dtm0_log ** out )

Typical call flow for calling DTM0 log interface routines:

** Initialisation/Finalisation for volatile fields of the log ** Create a persistent log or just allocate a volatile (in-memory) log m0_be_dtm0_log_create / m0_be_dtm0_log_alloc

m0_be_dtm0_log_init() ** Preparation phase
m0_be_dtm0_log_credit() ** Normal operation phase
m0_be_dtm0_log_update()
m0_be_dtm0_log_prune()
m0_be_dtm0_log_find() Allocate an m0_be_dtm0_log. This call will allocate a dtm0 volatile log. We need to call this routine once before we can perform any operations on .

Precondition: log != NULL.

Postcondition: *log is allocated and ready to be initialized.

Parameters

log	Pointer to variable in which to return the allocate memory address.

Returns: 0 on success. Anything else is a failure.

Allocate memory for a dtm0 volatile log structure.

Definition at line 70 of file dtm0_log.c.

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◆ m0_be_dtm0_log_clear()

M0_INTERNAL void m0_be_dtm0_log_clear ( struct m0_be_dtm0_log * log )

Given a pointer to a dtm0 volatile log clear the log and finalize it.

Precondition: log is not a persistent log; m0_dtm0_tx_desc_state_eq == M0_DTPS_PERSISTENT for all records in the log.

Postcondition: None

Parameters

log	Pointer to the volatile log that we want to clear.

Returns: None.

TODO: rename this to indicate that it's used for volatile usecase only. TODO: remove later. Removes all records from the volatile log.

Definition at line 520 of file dtm0_log.c.

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◆ m0_be_dtm0_log_create()

M0_INTERNAL int m0_be_dtm0_log_create	(	struct m0_be_tx *	tx,
		struct m0_be_seg *	seg,
		struct m0_be_dtm0_log **	out
	)

This routine is used to create a dtm0 persistent log.

Precondition: tx != NULL; seg != NULL

Postcondition: None

Parameters

tx	handle to an already opened transaction.
seg	be segment on which to create the log.
out	variable in which to store the pointer to the newly created log.

Returns: 0 on success, anything else is a failure.

Definition at line 237 of file dtm0_log.c.

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◆ m0_be_dtm0_log_credit()

M0_INTERNAL void m0_be_dtm0_log_credit	(	enum m0_be_dtm0_log_credit_op	op,
		struct m0_dtm0_tx_desc *	txd,
		struct m0_buf *	payload,
		struct m0_be_seg *	seg,
		struct m0_dtm0_log_rec *	rec,
		struct m0_be_tx_credit *	accum
	)

For performing an operation on a persistent log, we need to take the appropriate number of be transaction credit.

Precondition: op in enum m0_be_dtm0_log_credit_op seg != NULL accum != NULL

Postcondition: None

Parameters

op	Operation code for the type of dtm0 log operation that we want to perform.

See also: m0_be_dtm0_log_credit_op.

Parameters

txd	A valid dtm0 tx descriptor that we want to store in the log record.
payload	The payload is an opaque structure for dtm0 log to store in the log record.
seg	The be segment on which the log resides.
A	pointer to a valid m0_dtm0_log_rec.
accum	This contains the number of credits required for performing the operation.

Returns: None

Definition at line 202 of file dtm0_log.c.

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◆ m0_be_dtm0_log_destroy()

M0_INTERNAL void m0_be_dtm0_log_destroy	(	struct m0_be_tx *	tx,
		struct m0_be_dtm0_log **	log
	)

This routine is used to destroy a previously created persistent dtm0 log

Precondition: tx != NULL; *log != NULL

Postcondition: None

Parameters

tx	handle to an already opened transaction.
log	Pointer to the dtm0 log which we wish to destroy

Returns: None

Definition at line 260 of file dtm0_log.c.

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◆ m0_be_dtm0_log_find()

M0_INTERNAL struct m0_dtm0_log_rec* m0_be_dtm0_log_find	(	struct m0_be_dtm0_log *	log,
		const struct m0_dtm0_tid *	id
	)

Given a pointer to a dtm0 transaction id, this routine searches the log for the log record matching this tx id and returns it.

Precondition: m0_be_dtm0_log__invariant(log); m0_dtm0_tid__invariant(id)); m0_mutex_is_locked(&log->dl_lock)

Postcondition: None

Parameters

log	Pointer to the dtm0 log in which we wish to search.
tid	Pointer to a dtm0 transaction id corresponding to the record that we wish to fetch from the log.

Returns: m0_dtm0_log_rec corresponding to the input tid or NULL if no such record is found.

Definition at line 270 of file dtm0_log.c.

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◆ m0_be_dtm0_log_fini()

M0_INTERNAL void m0_be_dtm0_log_fini ( struct m0_be_dtm0_log * log )

Finalize a dtm0 log. We need to call this routine once after we have finished performing all operations on it.

Precondition: m0_be_dtm0_log__invariant needs to be satisfied.

Postcondition: All fields of *log are finalized. For volatile log the memory allocated by m0_be_dtm0_log_alloc is freed.

Parameters

log	Pointer to a valid log.

Returns: None

Definition at line 111 of file dtm0_log.c.

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◆ m0_be_dtm0_log_free()

M0_INTERNAL void m0_be_dtm0_log_free ( struct m0_be_dtm0_log ** log )

Free the memory allocated by m0_be_dtm0_log_alloc

Precondition: m0_be_dtm0_log->dl_is_persistent needs to be false.

Postcondition: *log is set to NULL.

Parameters

log	Pointer to a log structure that has been previously allocated.

Returns: None

Definition at line 119 of file dtm0_log.c.

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◆ m0_be_dtm0_log_init()

M0_INTERNAL int m0_be_dtm0_log_init	(	struct m0_be_dtm0_log *	log,
		struct m0_be_seg *	seg,
		struct m0_dtm0_clk_src *	cs,
		bool	is_plog
	)

Initialize a dtm0 log. We need to call this routine once before we can perform any operations on it.

Precondition: log != NULL;; cs != NULL;

Postcondition: *log is initialized and ready to be used

Parameters

log	Pointer to a m0_be_dtm0_log that has to be initialized.
cs	Pointer to a clock source. This will be used for comparisons involving log record timestamps.
is_plog	A flag to indicate whether the dtm0 log that we are trying to init is a volatile of persistent store.

Returns: 0 on success. Anything else is a failure.

Definition at line 94 of file dtm0_log.c.

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◆ m0_be_dtm0_log_pmsg_post()

M0_INTERNAL void m0_be_dtm0_log_pmsg_post	(	struct m0_be_dtm0_log *	log,
		struct m0_fop *	fop
	)

Deliver a persistent message to the log.

Precondition: log is a volatile log; fop->f_type ==

Postcondition: None

Parameters

log	Pointer to the dtm0 log which we wish to destroy
fop	This is a fop for the request carrying a PERSISTENT notice

Returns: None

TODO: Only volatile log is supported so far.

Definition at line 637 of file dtm0_log.c.

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◆ m0_be_dtm0_log_prune()

M0_INTERNAL int m0_be_dtm0_log_prune	(	struct m0_be_dtm0_log *	log,
		struct m0_be_tx *	tx,
		const struct m0_dtm0_tid *	id
	)

Given a pointer to a dtm0 transaction id, this routine searches the log for the log record matching this tx id and removes all the records having id lower or equal to the specified id.

Precondition: *log->dl_is_persistent == false (This is a volatile log); m0_be_dtm0_log__invariant(log); m0_dtm0_tid__invariant(id); m0_mutex_is_locked(&log->dl_lock)

Postcondition: None

Parameters

log	Pointer to the log from which we want to delete the record.
tx	Pointer to an open be transaction.
id	Pointer to a dtm0 transaction id corresponding to the record that we wish to delete from the log.

Returns: -ENOENT if no record exists for this id, 0 if the record is found and successfully deleted, Anything else is considered a failure.

Definition at line 477 of file dtm0_log.c.

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◆ m0_be_dtm0_log_update()

M0_INTERNAL int m0_be_dtm0_log_update	(	struct m0_be_dtm0_log *	log,
		struct m0_be_tx *	tx,
		struct m0_dtm0_tx_desc *	txd,
		struct m0_buf *	payload
	)

This routine is used to update a record in the dtm0 log. If the record does not exist it will be inserted.

Precondition: payload != NULL; m0_be_dtm0_log__invariant(log); m0_dtm0_tx_desc__invariant(txd); m0_mutex_is_locked(&log->dl_lock)

Postcondition: None

Parameters

log	Pointer to the dtm0 log which we wish to update.
tx	handle to an already opened transaction.
txd	A valid dtm0 tx descriptor that we want to store in the log record.
payload	The payload is an opaque structure for dtm0 log to store in the log record.

Returns: 0 on success, anything else is a failure.

Definition at line 460 of file dtm0_log.c.

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◆ m0_be_dtm0_plog_can_prune()

M0_INTERNAL bool m0_be_dtm0_plog_can_prune	(	struct m0_be_dtm0_log *	log,
		const struct m0_dtm0_tid *	id,
		struct m0_be_tx_credit *	accum
	)

Given a pointer to a dtm0 persistent log and a transaction id, this routine searches the log for the log record matching this tx id and checks whether all log records with id lower or equal to the specified id are persistent and if they can be pruned.

Precondition: m0_be_dtm0_log__invariant(log); m0_dtm0_tid__invariant(id); m0_mutex_is_locked(&log->dl_lock)

Postcondition: None

Parameters

log	Pointer to the log from which we want to delete the record.
tx	Pointer to an open be transaction.
id	Pointer to a dtm0 transaction id corresponding to the record that we wish to delete from the log.

Returns: -ENOENT if no record exists for this tid, 0 if the record is found and all previous records in the log including this record can be successfully deleted, -EPROTO if the record is found but NOT all previous records in the log can be deleted, Anything else is considered a failure.

To prune a record from the log, it needs to be persistent in the log and all the records in the log with id lower than this must be persistent as well. And, when we delete this record we will need to delete all such records. This function is used to determine whether the record with the given id can be pruned from the log and if yes, it also returns a count of the number of be tx credits that would be requried to delete these many records.

Definition at line 573 of file dtm0_log.c.

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◆ m0_be_dtm0_plog_prune()

M0_INTERNAL int m0_be_dtm0_plog_prune	(	struct m0_be_dtm0_log *	log,
		struct m0_be_tx *	tx,
		const struct m0_dtm0_tid *	id
	)

Given a pointer to a dtm0 persistent log and a transaction id, this routine searches the log for the log record matching this tx id and removes all the log records with id lower or equal to the specified id that are persistent.

Precondition: *log->dl_is_persistent == true; m0_be_dtm0_log__invariant(log); m0_dtm0_tid__invariant(id); m0_mutex_is_locked(&log->dl_lock)

Postcondition: None

Parameters

log	Pointer to the log from which we want to delete the record.
tx	Pointer to an open be transaction.
id	Pointer to a dtm0 transaction id corresponding to the record that we wish to delete from the log.

Returns: -ENOENT if no record exists for this id, 0 if the record is found and successfully deleted, Anything else is considered a failure.

Definition at line 609 of file dtm0_log.c.

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◆ m0_be_dtm0_volatile_log_insert()

M0_INTERNAL int m0_be_dtm0_volatile_log_insert	(	struct m0_be_dtm0_log *	log,
		struct m0_dtm0_log_rec *	rec
	)

Given a pointer to a dtm0 volatile log and a log record, insert the record in the log.

Precondition: log is a volatile log; rec is initialized and valid

Postcondition: None

Parameters

log	Pointer to the volatile log into which that we want to insert the record.

Returns: None.

Definition at line 540 of file dtm0_log.c.

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◆ m0_be_dtm0_volatile_log_update()

M0_INTERNAL void m0_be_dtm0_volatile_log_update	(	struct m0_be_dtm0_log *	log,
		struct m0_dtm0_log_rec *	rec
	)

This routine is used to update a record in a dtm0 volatile log.

Precondition: log is a volatile log; rec is initialized and valid

Postcondition: None

Parameters

log	Pointer to the dtm0 log which we wish to destroy
rec	Pointer to a valid dtm0 log record that we want to update.

Returns: None

Definition at line 555 of file dtm0_log.c.

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Data Structures

Enumerations

Functions

Detailed Description

section describes the dtm0 log related enumerations and structures.

Enumeration Type Documentation

◆ m0_be_dtm0_log_credit_op

Function Documentation

◆ m0_be_dtm0_log_alloc()

◆ m0_be_dtm0_log_clear()

◆ m0_be_dtm0_log_create()

◆ m0_be_dtm0_log_credit()

◆ m0_be_dtm0_log_destroy()

◆ m0_be_dtm0_log_find()

◆ m0_be_dtm0_log_fini()

◆ m0_be_dtm0_log_free()

◆ m0_be_dtm0_log_init()

◆ m0_be_dtm0_log_pmsg_post()

◆ m0_be_dtm0_log_prune()

◆ m0_be_dtm0_log_update()

◆ m0_be_dtm0_plog_can_prune()

◆ m0_be_dtm0_plog_prune()

◆ m0_be_dtm0_volatile_log_insert()

◆ m0_be_dtm0_volatile_log_update()