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- // 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;
- };
- static inline size_t
- xfs_efi_log_item_sizeof(
- unsigned int nr)
- {
- return offsetof(struct xfs_efi_log_item, efi_format) +
- xfs_efi_log_format_sizeof(nr);
- }
- /*
- * 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;
- };
- static inline size_t
- xfs_efd_log_item_sizeof(
- unsigned int nr)
- {
- return offsetof(struct xfs_efd_log_item, efd_format) +
- xfs_efd_log_format_sizeof(nr);
- }
- /*
- * 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__ */
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