13241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 23241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * Copyright (C) 2011 Red Hat, Inc. 33241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * 43241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * This file is released under the GPL. 53241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 63241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 73241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber#ifndef _LINUX_DM_BLOCK_MANAGER_H 83241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber#define _LINUX_DM_BLOCK_MANAGER_H 93241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 103241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber#include <linux/types.h> 113241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber#include <linux/blkdev.h> 123241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 133241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/*----------------------------------------------------------------*/ 143241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 153241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 163241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * Block number. 173241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 183241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornbertypedef uint64_t dm_block_t; 193241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberstruct dm_block; 203241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 213241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberdm_block_t dm_block_location(struct dm_block *b); 223241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornbervoid *dm_block_data(struct dm_block *b); 233241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 243241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/*----------------------------------------------------------------*/ 253241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 263241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 273241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * @name should be a unique identifier for the block manager, no longer 283241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * than 32 chars. 293241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * 303241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * @max_held_per_thread should be the maximum number of locks, read or 313241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * write, that an individual thread holds at any one time. 323241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 333241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberstruct dm_block_manager; 343241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberstruct dm_block_manager *dm_block_manager_create( 353241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct block_device *bdev, unsigned block_size, 363241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber unsigned cache_size, unsigned max_held_per_thread); 373241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornbervoid dm_block_manager_destroy(struct dm_block_manager *bm); 383241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 393241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberunsigned dm_bm_block_size(struct dm_block_manager *bm); 403241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberdm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm); 413241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 423241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/*----------------------------------------------------------------*/ 433241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 443241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 453241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * The validator allows the caller to verify newly-read data and modify 463241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * the data just before writing, e.g. to calculate checksums. It's 473241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * important to be consistent with your use of validators. The only time 483241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * you can change validators is if you call dm_bm_write_lock_zero. 493241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 503241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberstruct dm_block_validator { 513241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber const char *name; 523241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber void (*prepare_for_write)(struct dm_block_validator *v, struct dm_block *b, size_t block_size); 533241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 543241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber /* 553241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * Return 0 if the checksum is valid or < 0 on error. 563241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 573241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber int (*check)(struct dm_block_validator *v, struct dm_block *b, size_t block_size); 583241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber}; 593241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 603241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/*----------------------------------------------------------------*/ 613241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 623241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 633241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * You can have multiple concurrent readers or a single writer holding a 643241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * block lock. 653241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 663241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 673241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 683241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * dm_bm_lock() locks a block and returns through @result a pointer to 693241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * memory that holds a copy of that block. If you have write-locked the 703241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * block then any changes you make to memory pointed to by @result will be 713241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * written back to the disk sometime after dm_bm_unlock is called. 723241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 733241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberint dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b, 743241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct dm_block_validator *v, 753241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct dm_block **result); 763241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 773241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberint dm_bm_write_lock(struct dm_block_manager *bm, dm_block_t b, 783241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct dm_block_validator *v, 793241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct dm_block **result); 803241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 813241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 823241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * The *_try_lock variants return -EWOULDBLOCK if the block isn't 833241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * available immediately. 843241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 853241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberint dm_bm_read_try_lock(struct dm_block_manager *bm, dm_block_t b, 863241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct dm_block_validator *v, 873241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct dm_block **result); 883241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 893241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 903241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * Use dm_bm_write_lock_zero() when you know you're going to 913241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * overwrite the block completely. It saves a disk read. 923241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 933241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberint dm_bm_write_lock_zero(struct dm_block_manager *bm, dm_block_t b, 943241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct dm_block_validator *v, 953241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber struct dm_block **result); 963241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 973241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberint dm_bm_unlock(struct dm_block *b); 983241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 993241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/* 1003241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * It's a common idiom to have a superblock that should be committed last. 1013241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * 1023241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * @superblock should be write-locked on entry. It will be unlocked during 1033241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * this function. All dirty blocks are guaranteed to be written and flushed 1043241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * before the superblock. 1053241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * 1063241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber * This method always blocks. 1073241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber */ 108a9d45396f5956d0b615c7ae3b936afd888351a47Joe Thornberint dm_bm_flush(struct dm_block_manager *bm); 1093241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 1109b7aaa64f96f7ca280d75326fca42f42017b89efJoe Thornber/* 1119b7aaa64f96f7ca280d75326fca42f42017b89efJoe Thornber * Request data is prefetched into the cache. 1129b7aaa64f96f7ca280d75326fca42f42017b89efJoe Thornber */ 11304f17c802f447e76d13ade5bb78fbbf34baef0f8Joe Thornbervoid dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b); 11404f17c802f447e76d13ade5bb78fbbf34baef0f8Joe Thornber 115310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber/* 116310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * Switches the bm to a read only mode. Once read-only mode 117310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * has been entered the following functions will return -EPERM. 118310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * 119310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * dm_bm_write_lock 120310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * dm_bm_write_lock_zero 121310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * dm_bm_flush_and_unlock 122310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * 123310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * Additionally you should not use dm_bm_unlock_move, however no error will 124310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber * be returned if you do. 125310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber */ 126310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornbervoid dm_bm_set_read_only(struct dm_block_manager *bm); 1279b7aaa64f96f7ca280d75326fca42f42017b89efJoe Thornbervoid dm_bm_set_read_write(struct dm_block_manager *bm); 128310975573ba40ab526b0d76d28225d8d0999d72bJoe Thornber 1293241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornberu32 dm_bm_checksum(const void *data, size_t len, u32 init_xor); 1303241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 1313241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber/*----------------------------------------------------------------*/ 1323241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber 1333241b1d3e0aaafbfcd320f4d71ade629728cc4f4Joe Thornber#endif /* _LINUX_DM_BLOCK_MANAGER_H */ 134