/* SPDX-License-Identifier: GPL-2.0 */ /* * bitmap.h: Copyright (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003 * * additions: Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc. */ #ifndef BITMAP_H #define BITMAP_H 1 #define BITMAP_MAJOR_LO 3 /* version 4 insists the bitmap is in little-endian order * with version 3, it is host-endian which is non-portable * Version 5 is currently set only for clustered devices */ #define BITMAP_MAJOR_HI 4 #define BITMAP_MAJOR_CLUSTERED 5 #define BITMAP_MAJOR_HOSTENDIAN 3 /* * in-memory bitmap: * * Use 16 bit block counters to track pending writes to each "chunk". * The 2 high order bits are special-purpose, the first is a flag indicating * whether a resync is needed. The second is a flag indicating whether a * resync is active. * This means that the counter is actually 14 bits: * * +--------+--------+------------------------------------------------+ * | resync | resync | counter | * | needed | active | | * | (0-1) | (0-1) | (0-16383) | * +--------+--------+------------------------------------------------+ * * The "resync needed" bit is set when: * a '1' bit is read from storage at startup. * a write request fails on some drives * a resync is aborted on a chunk with 'resync active' set * It is cleared (and resync-active set) when a resync starts across all drives * of the chunk. * * * The "resync active" bit is set when: * a resync is started on all drives, and resync_needed is set. * resync_needed will be cleared (as long as resync_active wasn't already set). * It is cleared when a resync completes. * * The counter counts pending write requests, plus the on-disk bit. * When the counter is '1' and the resync bits are clear, the on-disk * bit can be cleared as well, thus setting the counter to 0. * When we set a bit, or in the counter (to start a write), if the fields is * 0, we first set the disk bit and set the counter to 1. * * If the counter is 0, the on-disk bit is clear and the stripe is clean * Anything that dirties the stripe pushes the counter to 2 (at least) * and sets the on-disk bit (lazily). * If a periodic sweep find the counter at 2, it is decremented to 1. * If the sweep find the counter at 1, the on-disk bit is cleared and the * counter goes to zero. * * Also, we'll hijack the "map" pointer itself and use it as two 16 bit block * counters as a fallback when "page" memory cannot be allocated: * * Normal case (page memory allocated): * * page pointer (32-bit) * * [ ] ------+ * | * +-------> [ ][ ]..[ ] (4096 byte page == 2048 counters) * c1 c2 c2048 * * Hijacked case (page memory allocation failed): * * hijacked page pointer (32-bit) * * [ ][ ] (no page memory allocated) * counter #1 (16-bit) counter #2 (16-bit) * */ #ifdef __KERNEL__ #define PAGE_BITS (PAGE_SIZE << 3) #define PAGE_BIT_SHIFT (PAGE_SHIFT + 3) typedef __u16 bitmap_counter_t; #define COUNTER_BITS 16 #define COUNTER_BIT_SHIFT 4 #define COUNTER_BYTE_SHIFT (COUNTER_BIT_SHIFT - 3) #define NEEDED_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 1))) #define RESYNC_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 2))) #define COUNTER_MAX ((bitmap_counter_t) RESYNC_MASK - 1) #define NEEDED(x) (((bitmap_counter_t) x) & NEEDED_MASK) #define RESYNC(x) (((bitmap_counter_t) x) & RESYNC_MASK) #define COUNTER(x) (((bitmap_counter_t) x) & COUNTER_MAX) /* how many counters per page? */ #define PAGE_COUNTER_RATIO (PAGE_BITS / COUNTER_BITS) /* same, except a shift value for more efficient bitops */ #define PAGE_COUNTER_SHIFT (PAGE_BIT_SHIFT - COUNTER_BIT_SHIFT) /* same, except a mask value for more efficient bitops */ #define PAGE_COUNTER_MASK (PAGE_COUNTER_RATIO - 1) #define BITMAP_BLOCK_SHIFT 9 #endif /* * bitmap structures: */ #define BITMAP_MAGIC 0x6d746962 /* use these for bitmap->flags and bitmap->sb->state bit-fields */ enum bitmap_state { BITMAP_STALE = 1, /* the bitmap file is out of date or had -EIO */ BITMAP_WRITE_ERROR = 2, /* A write error has occurred */ BITMAP_HOSTENDIAN =15, }; /* the superblock at the front of the bitmap file -- little endian */ typedef struct bitmap_super_s { __le32 magic; /* 0 BITMAP_MAGIC */ __le32 version; /* 4 the bitmap major for now, could change... */ __u8 uuid[16]; /* 8 128 bit uuid - must match md device uuid */ __le64 events; /* 24 event counter for the bitmap (1)*/ __le64 events_cleared;/*32 event counter when last bit cleared (2) */ __le64 sync_size; /* 40 the size of the md device's sync range(3) */ __le32 state; /* 48 bitmap state information */ __le32 chunksize; /* 52 the bitmap chunk size in bytes */ __le32 daemon_sleep; /* 56 seconds between disk flushes */ __le32 write_behind; /* 60 number of outstanding write-behind writes */ __le32 sectors_reserved; /* 64 number of 512-byte sectors that are * reserved for the bitmap. */ __le32 nodes; /* 68 the maximum number of nodes in cluster. */ __u8 cluster_name[64]; /* 72 cluster name to which this md belongs */ __u8 pad[256 - 136]; /* set to zero */ } bitmap_super_t; /* notes: * (1) This event counter is updated before the eventcounter in the md superblock * When a bitmap is loaded, it is only accepted if this event counter is equal * to, or one greater than, the event counter in the superblock. * (2) This event counter is updated when the other one is *if*and*only*if* the * array is not degraded. As bits are not cleared when the array is degraded, * this represents the last time that any bits were cleared. * If a device is being added that has an event count with this value or * higher, it is accepted as conforming to the bitmap. * (3)This is the number of sectors represented by the bitmap, and is the range that * resync happens across. For raid1 and raid5/6 it is the size of individual * devices. For raid10 it is the size of the array. */ #ifdef __KERNEL__ /* the in-memory bitmap is represented by bitmap_pages */ struct bitmap_page { /* * map points to the actual memory page */ char *map; /* * in emergencies (when map cannot be alloced), hijack the map * pointer and use it as two counters itself */ unsigned int hijacked:1; /* * If any counter in this page is '1' or '2' - and so could be * cleared then that page is marked as 'pending' */ unsigned int pending:1; /* * count of dirty bits on the page */ unsigned int count:30; }; /* the main bitmap structure - one per mddev */ struct bitmap { struct bitmap_counts { spinlock_t lock; struct bitmap_page *bp; unsigned long pages; /* total number of pages * in the bitmap */ unsigned long missing_pages; /* number of pages * not yet allocated */ unsigned long chunkshift; /* chunksize = 2^chunkshift * (for bitops) */ unsigned long chunks; /* Total number of data * chunks for the array */ } counts; struct mddev *mddev; /* the md device that the bitmap is for */ __u64 events_cleared; int need_sync; struct bitmap_storage { struct file *file; /* backing disk file */ struct page *sb_page; /* cached copy of the bitmap * file superblock */ unsigned long sb_index; struct page **filemap; /* list of cache pages for * the file */ unsigned long *filemap_attr; /* attributes associated * w/ filemap pages */ unsigned long file_pages; /* number of pages in the file*/ unsigned long bytes; /* total bytes in the bitmap */ } storage; unsigned long flags; int allclean; atomic_t behind_writes; unsigned long behind_writes_used; /* highest actual value at runtime */ /* * the bitmap daemon - periodically wakes up and sweeps the bitmap * file, cleaning up bits and flushing out pages to disk as necessary */ unsigned long daemon_lastrun; /* jiffies of last run */ unsigned long last_end_sync; /* when we lasted called end_sync to * update bitmap with resync progress */ atomic_t pending_writes; /* pending writes to the bitmap file */ wait_queue_head_t write_wait; wait_queue_head_t overflow_wait; wait_queue_head_t behind_wait; struct kernfs_node *sysfs_can_clear; int cluster_slot; /* Slot offset for clustered env */ }; /* the bitmap API */ /* these are used only by md/bitmap */ struct bitmap *md_bitmap_create(struct mddev *mddev, int slot); int md_bitmap_load(struct mddev *mddev); void md_bitmap_flush(struct mddev *mddev); void md_bitmap_destroy(struct mddev *mddev); void md_bitmap_print_sb(struct bitmap *bitmap); void md_bitmap_update_sb(struct bitmap *bitmap); void md_bitmap_status(struct seq_file *seq, struct bitmap *bitmap); int md_bitmap_setallbits(struct bitmap *bitmap); void md_bitmap_write_all(struct bitmap *bitmap); void md_bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e); /* these are exported */ int md_bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind); void md_bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int success, int behind); int md_bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int degraded); void md_bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted); void md_bitmap_close_sync(struct bitmap *bitmap); void md_bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force); void md_bitmap_sync_with_cluster(struct mddev *mddev, sector_t old_lo, sector_t old_hi, sector_t new_lo, sector_t new_hi); void md_bitmap_unplug(struct bitmap *bitmap); void md_bitmap_unplug_async(struct bitmap *bitmap); void md_bitmap_daemon_work(struct mddev *mddev); int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks, int chunksize, int init); struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot); int md_bitmap_copy_from_slot(struct mddev *mddev, int slot, sector_t *lo, sector_t *hi, bool clear_bits); void md_bitmap_free(struct bitmap *bitmap); void md_bitmap_wait_behind_writes(struct mddev *mddev); static inline bool md_bitmap_enabled(struct bitmap *bitmap) { return bitmap && bitmap->storage.filemap && !test_bit(BITMAP_STALE, &bitmap->flags); } #endif #endif