76 lines
2.6 KiB
C
76 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2000,2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*/
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#ifndef __XFS_EXTFREE_ITEM_H__
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#define __XFS_EXTFREE_ITEM_H__
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/* kernel only EFI/EFD definitions */
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struct xfs_mount;
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struct kmem_cache;
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/*
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* Max number of extents in fast allocation path.
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*/
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#define XFS_EFI_MAX_FAST_EXTENTS 16
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/*
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* This is the "extent free intention" log item. It is used to log the fact
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* that some extents need to be free. It is used in conjunction with the
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* "extent free done" log item described below.
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*
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* The EFI is reference counted so that it is not freed prior to both the EFI
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* and EFD being committed and unpinned. This ensures the EFI is inserted into
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* the AIL even in the event of out of order EFI/EFD processing. In other words,
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* an EFI is born with two references:
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*
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* 1.) an EFI held reference to track EFI AIL insertion
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* 2.) an EFD held reference to track EFD commit
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*
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* On allocation, both references are the responsibility of the caller. Once the
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* EFI is added to and dirtied in a transaction, ownership of reference one
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* transfers to the transaction. The reference is dropped once the EFI is
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* inserted to the AIL or in the event of failure along the way (e.g., commit
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* failure, log I/O error, etc.). Note that the caller remains responsible for
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* the EFD reference under all circumstances to this point. The caller has no
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* means to detect failure once the transaction is committed, however.
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* Therefore, an EFD is required after this point, even in the event of
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* unrelated failure.
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*
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* Once an EFD is allocated and dirtied in a transaction, reference two
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* transfers to the transaction. The EFD reference is dropped once it reaches
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* the unpin handler. Similar to the EFI, the reference also drops in the event
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* of commit failure or log I/O errors. Note that the EFD is not inserted in the
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* AIL, so at this point both the EFI and EFD are freed.
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*/
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struct xfs_efi_log_item {
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struct xfs_log_item efi_item;
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atomic_t efi_refcount;
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atomic_t efi_next_extent;
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xfs_efi_log_format_t efi_format;
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};
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/*
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* This is the "extent free done" log item. It is used to log
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* the fact that some extents earlier mentioned in an efi item
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* have been freed.
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*/
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struct xfs_efd_log_item {
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struct xfs_log_item efd_item;
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struct xfs_efi_log_item *efd_efip;
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uint efd_next_extent;
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xfs_efd_log_format_t efd_format;
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};
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/*
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* Max number of extents in fast allocation path.
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*/
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#define XFS_EFD_MAX_FAST_EXTENTS 16
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extern struct kmem_cache *xfs_efi_cache;
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extern struct kmem_cache *xfs_efd_cache;
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#endif /* __XFS_EXTFREE_ITEM_H__ */
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