[people/ms/linux.git] / fs / xfs / xfs_extfree_item.h

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#ifndef	__XFS_EXTFREE_ITEM_H__
#define	__XFS_EXTFREE_ITEM_H__

/* kernel only EFI/EFD definitions */

struct xfs_mount;
struct kmem_cache;

/*
 * Max number of extents in fast allocation path.
 */
#define	XFS_EFI_MAX_FAST_EXTENTS	16

/*
 * This is the "extent free intention" log item.  It is used to log the fact
 * that some extents need to be free.  It is used in conjunction with the
 * "extent free done" log item described below.
 *
 * The EFI is reference counted so that it is not freed prior to both the EFI
 * and EFD being committed and unpinned. This ensures the EFI is inserted into
 * the AIL even in the event of out of order EFI/EFD processing. In other words,
 * an EFI is born with two references:
 *
 * 	1.) an EFI held reference to track EFI AIL insertion
 * 	2.) an EFD held reference to track EFD commit
 *
 * On allocation, both references are the responsibility of the caller. Once the
 * EFI is added to and dirtied in a transaction, ownership of reference one
 * transfers to the transaction. The reference is dropped once the EFI is
 * inserted to the AIL or in the event of failure along the way (e.g., commit
 * failure, log I/O error, etc.). Note that the caller remains responsible for
 * the EFD reference under all circumstances to this point. The caller has no
 * means to detect failure once the transaction is committed, however.
 * Therefore, an EFD is required after this point, even in the event of
 * unrelated failure.
 *
 * Once an EFD is allocated and dirtied in a transaction, reference two
 * transfers to the transaction. The EFD reference is dropped once it reaches
 * the unpin handler. Similar to the EFI, the reference also drops in the event
 * of commit failure or log I/O errors. Note that the EFD is not inserted in the
 * AIL, so at this point both the EFI and EFD are freed.
 */
struct xfs_efi_log_item {
	struct xfs_log_item	efi_item;
	atomic_t		efi_refcount;
	atomic_t		efi_next_extent;
	xfs_efi_log_format_t	efi_format;
};

/*
 * This is the "extent free done" log item.  It is used to log
 * the fact that some extents earlier mentioned in an efi item
 * have been freed.
 */
struct xfs_efd_log_item {
	struct xfs_log_item	efd_item;
	struct xfs_efi_log_item *efd_efip;
	uint			efd_next_extent;
	xfs_efd_log_format_t	efd_format;
};

/*
 * Max number of extents in fast allocation path.
 */
#define	XFS_EFD_MAX_FAST_EXTENTS	16

extern struct kmem_cache	*xfs_efi_cache;
extern struct kmem_cache	*xfs_efd_cache;

#endif	/* __XFS_EXTFREE_ITEM_H__ */
Commit	Line	Data
0b61f8a4	1	// SPDX-License-Identifier: GPL-2.0
1da177e4	2	/*
7b718769 NS	3	* Copyright (c) 2000,2005 Silicon Graphics, Inc.
7b718769 NS	4	* All Rights Reserved.
1da177e4 LT	5	*/
	6	#ifndef __XFS_EXTFREE_ITEM_H__
	7	#define __XFS_EXTFREE_ITEM_H__
	8
9fbe24d9 DC	9	/* kernel only EFI/EFD definitions */
9fbe24d9 DC	10
1da177e4	11	struct xfs_mount;
e7720afa	12	struct kmem_cache;
1da177e4	13
1da177e4 LT	14	/*
	15	* Max number of extents in fast allocation path.
	16	*/
	17	#define XFS_EFI_MAX_FAST_EXTENTS 16
	18
1da177e4	19	/*
666d644c DC	20	* This is the "extent free intention" log item. It is used to log the fact
	21	* that some extents need to be free. It is used in conjunction with the
	22	* "extent free done" log item described below.
	23	*
	24	* The EFI is reference counted so that it is not freed prior to both the EFI
8d99fe92 BF	25	* and EFD being committed and unpinned. This ensures the EFI is inserted into
	26	* the AIL even in the event of out of order EFI/EFD processing. In other words,
	27	* an EFI is born with two references:
	28	*
	29	* 1.) an EFI held reference to track EFI AIL insertion
	30	* 2.) an EFD held reference to track EFD commit
	31	*
	32	* On allocation, both references are the responsibility of the caller. Once the
	33	* EFI is added to and dirtied in a transaction, ownership of reference one
	34	* transfers to the transaction. The reference is dropped once the EFI is
	35	* inserted to the AIL or in the event of failure along the way (e.g., commit
	36	* failure, log I/O error, etc.). Note that the caller remains responsible for
	37	* the EFD reference under all circumstances to this point. The caller has no
	38	* means to detect failure once the transaction is committed, however.
	39	* Therefore, an EFD is required after this point, even in the event of
	40	* unrelated failure.
	41	*
	42	* Once an EFD is allocated and dirtied in a transaction, reference two
	43	* transfers to the transaction. The EFD reference is dropped once it reaches
	44	* the unpin handler. Similar to the EFI, the reference also drops in the event
	45	* of commit failure or log I/O errors. Note that the EFD is not inserted in the
	46	* AIL, so at this point both the EFI and EFD are freed.
1da177e4	47	*/
82ff450b	48	struct xfs_efi_log_item {
efe2330f	49	struct xfs_log_item efi_item;
666d644c	50	atomic_t efi_refcount;
b199c8a4	51	atomic_t efi_next_extent;
1da177e4	52	xfs_efi_log_format_t efi_format;
82ff450b	53	};
1da177e4 LT	54
	55	/*
	56	* This is the "extent free done" log item. It is used to log
	57	* the fact that some extents earlier mentioned in an efi item
	58	* have been freed.
	59	*/
c84e8190	60	struct xfs_efd_log_item {
efe2330f	61	struct xfs_log_item efd_item;
82ff450b	62	struct xfs_efi_log_item *efd_efip;
1da177e4 LT	63	uint efd_next_extent;
1da177e4 LT	64	xfs_efd_log_format_t efd_format;
c84e8190	65	};
1da177e4 LT	66
	67	/*
	68	* Max number of extents in fast allocation path.
	69	*/
	70	#define XFS_EFD_MAX_FAST_EXTENTS 16
	71
182696fb DW	72	extern struct kmem_cache *xfs_efi_cache;
182696fb DW	73	extern struct kmem_cache *xfs_efd_cache;
1da177e4	74
1da177e4	75	#endif /* __XFS_EXTFREE_ITEM_H__ */