diff options
Diffstat (limited to 'fs/xfs/xfs_extfree_item.h')
| -rw-r--r-- | fs/xfs/xfs_extfree_item.h | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/fs/xfs/xfs_extfree_item.h b/fs/xfs/xfs_extfree_item.h index 0ffbce32d569..8fa8651705e1 100644 --- a/fs/xfs/xfs_extfree_item.h +++ b/fs/xfs/xfs_extfree_item.h @@ -39,9 +39,28 @@ struct kmem_zone; * "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 that when the last - * reference goes away the EFI will always be in the AIL as it has been - * unpinned, regardless of whether the EFD is processed before or after 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. */ typedef struct xfs_efi_log_item { xfs_log_item_t efi_item; @@ -77,5 +96,6 @@ xfs_efd_log_item_t *xfs_efd_init(struct xfs_mount *, xfs_efi_log_item_t *, int xfs_efi_copy_format(xfs_log_iovec_t *buf, xfs_efi_log_format_t *dst_efi_fmt); void xfs_efi_item_free(xfs_efi_log_item_t *); +void xfs_efi_release(struct xfs_efi_log_item *); #endif /* __XFS_EXTFREE_ITEM_H__ */ |