1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2000,2005 Silicon Graphics, Inc. 4 * All Rights Reserved. 5 */ 6 #ifndef __XFS_EXTFREE_ITEM_H__ 7 #define __XFS_EXTFREE_ITEM_H__ 8 9 /* kernel only EFI/EFD definitions */ 10 11 struct xfs_mount; 12 struct kmem_zone; 13 14 /* 15 * Max number of extents in fast allocation path. 16 */ 17 #define XFS_EFI_MAX_FAST_EXTENTS 16 18 19 /* 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 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. 47 */ 48 struct xfs_efi_log_item { 49 struct xfs_log_item efi_item; 50 atomic_t efi_refcount; 51 atomic_t efi_next_extent; 52 xfs_efi_log_format_t efi_format; 53 }; 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 */ 60 struct xfs_efd_log_item { 61 struct xfs_log_item efd_item; 62 struct xfs_efi_log_item *efd_efip; 63 uint efd_next_extent; 64 xfs_efd_log_format_t efd_format; 65 }; 66 67 /* 68 * Max number of extents in fast allocation path. 69 */ 70 #define XFS_EFD_MAX_FAST_EXTENTS 16 71 72 extern struct kmem_zone *xfs_efi_zone; 73 extern struct kmem_zone *xfs_efd_zone; 74 75 #endif /* __XFS_EXTFREE_ITEM_H__ */ 76
