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Quellcodebibliothek Statistik Leitseite products/Sources/formale Sprachen/Cobol/Test-Suite/COBOL/SM/   (Linux Kernel Version 6.17.9©)  Datei vom 4.1.2008 mit Größe 56 kB image not shown  

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dm-exception-store.h


products/Sources/formale Sprachen/C/Linux/drivers/md/dm-exception-store.h

/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2001-2002 Sistina Software (UK) Limited. * Copyright (C) 2008 Red Hat, Inc. All rights reserved. * * Device-mapper snapshot exception store. * * This file is released under the GPL. */ #ifndef _LINUX_DM_EXCEPTION_STORE #define _LINUX_DM_EXCEPTION_STORE #include #include #include /* * The snapshot code deals with largish chunks of the disk at a * time. Typically 32k - 512k. */ typedef sector_t chunk_t; /* * An exception is used where an old chunk of data has been * replaced by a new one. * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number * of chunks that follow contiguously. Remaining bits hold the number of the * chunk within the device. */ struct dm_exception { struct hlist_bl_node hash_list; chunk_t old_chunk; chunk_t new_chunk; }; /* * Abstraction to handle the meta/layout of exception stores (the * COW device). */ struct dm_exception_store; struct dm_exception_store_type { const char *name; struct module *module; int (*ctr)(struct dm_exception_store *store, char *options); /* * Destroys this object when you've finished with it. */ void (*dtr)(struct dm_exception_store *store); /* * The target shouldn't read the COW device until this is * called. As exceptions are read from the COW, they are * reported back via the callback. */ int (*read_metadata)(struct dm_exception_store *store, int (*callback)(void *callback_context, chunk_t old, chunk_t new), void *callback_context); /* * Find somewhere to store the next exception. */ int (*prepare_exception)(struct dm_exception_store *store, struct dm_exception *e); /* * Update the metadata with this exception. */ void (*commit_exception)(struct dm_exception_store *store, struct dm_exception *e, int valid, void (*callback)(void *, int success), void *callback_context); /* * Returns 0 if the exception store is empty. * * If there are exceptions still to be merged, sets * *last_old_chunk and *last_new_chunk to the most recent * still-to-be-merged chunk and returns the number of * consecutive previous ones. */ int (*prepare_merge)(struct dm_exception_store *store, chunk_t *last_old_chunk, chunk_t *last_new_chunk); /* * Clear the last n exceptions. * nr_merged must be <= the value returned by prepare_merge. */ int (*commit_merge)(struct dm_exception_store *store, int nr_merged); /* * The snapshot is invalid, note this in the metadata. */ void (*drop_snapshot)(struct dm_exception_store *store); unsigned int (*status)(struct dm_exception_store *store, status_type_t status, char *result, unsigned int maxlen); /* * Return how full the snapshot is. */ void (*usage)(struct dm_exception_store *store, sector_t *total_sectors, sector_t *sectors_allocated, sector_t *metadata_sectors); /* For internal device-mapper use only. */ struct list_head list; }; struct dm_snapshot; struct dm_exception_store { struct dm_exception_store_type *type; struct dm_snapshot *snap; /* Size of data blocks saved - must be a power of 2 */ unsigned int chunk_size; unsigned int chunk_mask; unsigned int chunk_shift; void *context; bool userspace_supports_overflow; }; /* * Obtain the origin or cow device used by a given snapshot. */ struct dm_dev *dm_snap_origin(struct dm_snapshot *snap); struct dm_dev *dm_snap_cow(struct dm_snapshot *snap); /* * Funtions to manipulate consecutive chunks */ #define DM_CHUNK_CONSECUTIVE_BITS 8 #define DM_CHUNK_NUMBER_BITS 56 static inline chunk_t dm_chunk_number(chunk_t chunk) { return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL); } static inline unsigned int dm_consecutive_chunk_count(struct dm_exception *e) { return e->new_chunk >> DM_CHUNK_NUMBER_BITS; } static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e) { e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS); BUG_ON(!dm_consecutive_chunk_count(e)); } static inline void dm_consecutive_chunk_count_dec(struct dm_exception *e) { BUG_ON(!dm_consecutive_chunk_count(e)); e->new_chunk -= (1ULL << DM_CHUNK_NUMBER_BITS); } /* * Return the number of sectors in the device. */ static inline sector_t get_dev_size(struct block_device *bdev) { return bdev_nr_sectors(bdev); } static inline chunk_t sector_to_chunk(struct dm_exception_store *store, sector_t sector) { return sector >> store->chunk_shift; } int dm_exception_store_type_register(struct dm_exception_store_type *type); int dm_exception_store_type_unregister(struct dm_exception_store_type *type); int dm_exception_store_set_chunk_size(struct dm_exception_store *store, unsigned int chunk_size, char **error); int dm_exception_store_create(struct dm_target *ti, int argc, char **argv, struct dm_snapshot *snap, unsigned int *args_used, struct dm_exception_store **store); void dm_exception_store_destroy(struct dm_exception_store *store); int dm_exception_store_init(void); void dm_exception_store_exit(void); /* * Two exception store implementations. */ int dm_persistent_snapshot_init(void); void dm_persistent_snapshot_exit(void); int dm_transient_snapshot_init(void); void dm_transient_snapshot_exit(void); #endif /* _LINUX_DM_EXCEPTION_STORE */

                                                                                                                                                                                                                                                                                                                                                                                                     

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