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1660 lines
47 KiB
1660 lines
47 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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drbd_bitmap.c |
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This file is part of DRBD by Philipp Reisner and Lars Ellenberg. |
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Copyright (C) 2004-2008, LINBIT Information Technologies GmbH. |
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Copyright (C) 2004-2008, Philipp Reisner <[email protected]>. |
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Copyright (C) 2004-2008, Lars Ellenberg <[email protected]>. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/bitmap.h> |
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#include <linux/vmalloc.h> |
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#include <linux/string.h> |
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#include <linux/drbd.h> |
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#include <linux/slab.h> |
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#include <linux/highmem.h> |
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#include "drbd_int.h" |
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/* OPAQUE outside this file! |
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* interface defined in drbd_int.h |
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* convention: |
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* function name drbd_bm_... => used elsewhere, "public". |
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* function name bm_... => internal to implementation, "private". |
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*/ |
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/* |
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* LIMITATIONS: |
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* We want to support >= peta byte of backend storage, while for now still using |
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* a granularity of one bit per 4KiB of storage. |
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* 1 << 50 bytes backend storage (1 PiB) |
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* 1 << (50 - 12) bits needed |
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* 38 --> we need u64 to index and count bits |
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* 1 << (38 - 3) bitmap bytes needed |
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* 35 --> we still need u64 to index and count bytes |
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* (that's 32 GiB of bitmap for 1 PiB storage) |
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* 1 << (35 - 2) 32bit longs needed |
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* 33 --> we'd even need u64 to index and count 32bit long words. |
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* 1 << (35 - 3) 64bit longs needed |
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* 32 --> we could get away with a 32bit unsigned int to index and count |
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* 64bit long words, but I rather stay with unsigned long for now. |
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* We probably should neither count nor point to bytes or long words |
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* directly, but either by bitnumber, or by page index and offset. |
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* 1 << (35 - 12) |
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* 22 --> we need that much 4KiB pages of bitmap. |
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* 1 << (22 + 3) --> on a 64bit arch, |
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* we need 32 MiB to store the array of page pointers. |
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* |
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* Because I'm lazy, and because the resulting patch was too large, too ugly |
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* and still incomplete, on 32bit we still "only" support 16 TiB (minus some), |
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* (1 << 32) bits * 4k storage. |
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* |
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* bitmap storage and IO: |
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* Bitmap is stored little endian on disk, and is kept little endian in |
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* core memory. Currently we still hold the full bitmap in core as long |
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* as we are "attached" to a local disk, which at 32 GiB for 1PiB storage |
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* seems excessive. |
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* |
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* We plan to reduce the amount of in-core bitmap pages by paging them in |
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* and out against their on-disk location as necessary, but need to make |
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* sure we don't cause too much meta data IO, and must not deadlock in |
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* tight memory situations. This needs some more work. |
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*/ |
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/* |
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* NOTE |
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* Access to the *bm_pages is protected by bm_lock. |
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* It is safe to read the other members within the lock. |
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* |
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* drbd_bm_set_bits is called from bio_endio callbacks, |
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* We may be called with irq already disabled, |
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* so we need spin_lock_irqsave(). |
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* And we need the kmap_atomic. |
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*/ |
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struct drbd_bitmap { |
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struct page **bm_pages; |
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spinlock_t bm_lock; |
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/* exclusively to be used by __al_write_transaction(), |
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* drbd_bm_mark_for_writeout() and |
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* and drbd_bm_write_hinted() -> bm_rw() called from there. |
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*/ |
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unsigned int n_bitmap_hints; |
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unsigned int al_bitmap_hints[AL_UPDATES_PER_TRANSACTION]; |
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/* see LIMITATIONS: above */ |
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unsigned long bm_set; /* nr of set bits; THINK maybe atomic_t? */ |
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unsigned long bm_bits; |
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size_t bm_words; |
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size_t bm_number_of_pages; |
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sector_t bm_dev_capacity; |
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struct mutex bm_change; /* serializes resize operations */ |
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wait_queue_head_t bm_io_wait; /* used to serialize IO of single pages */ |
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enum bm_flag bm_flags; |
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/* debugging aid, in case we are still racy somewhere */ |
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char *bm_why; |
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struct task_struct *bm_task; |
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}; |
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#define bm_print_lock_info(m) __bm_print_lock_info(m, __func__) |
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static void __bm_print_lock_info(struct drbd_device *device, const char *func) |
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{ |
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struct drbd_bitmap *b = device->bitmap; |
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if (!__ratelimit(&drbd_ratelimit_state)) |
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return; |
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drbd_err(device, "FIXME %s[%d] in %s, bitmap locked for '%s' by %s[%d]\n", |
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current->comm, task_pid_nr(current), |
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func, b->bm_why ?: "?", |
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b->bm_task->comm, task_pid_nr(b->bm_task)); |
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} |
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void drbd_bm_lock(struct drbd_device *device, char *why, enum bm_flag flags) |
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{ |
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struct drbd_bitmap *b = device->bitmap; |
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int trylock_failed; |
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if (!b) { |
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drbd_err(device, "FIXME no bitmap in drbd_bm_lock!?\n"); |
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return; |
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} |
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trylock_failed = !mutex_trylock(&b->bm_change); |
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if (trylock_failed) { |
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drbd_warn(device, "%s[%d] going to '%s' but bitmap already locked for '%s' by %s[%d]\n", |
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current->comm, task_pid_nr(current), |
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why, b->bm_why ?: "?", |
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b->bm_task->comm, task_pid_nr(b->bm_task)); |
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mutex_lock(&b->bm_change); |
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} |
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if (BM_LOCKED_MASK & b->bm_flags) |
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drbd_err(device, "FIXME bitmap already locked in bm_lock\n"); |
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b->bm_flags |= flags & BM_LOCKED_MASK; |
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b->bm_why = why; |
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b->bm_task = current; |
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} |
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void drbd_bm_unlock(struct drbd_device *device) |
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{ |
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struct drbd_bitmap *b = device->bitmap; |
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if (!b) { |
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drbd_err(device, "FIXME no bitmap in drbd_bm_unlock!?\n"); |
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return; |
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} |
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if (!(BM_LOCKED_MASK & device->bitmap->bm_flags)) |
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drbd_err(device, "FIXME bitmap not locked in bm_unlock\n"); |
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b->bm_flags &= ~BM_LOCKED_MASK; |
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b->bm_why = NULL; |
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b->bm_task = NULL; |
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mutex_unlock(&b->bm_change); |
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} |
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/* we store some "meta" info about our pages in page->private */ |
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/* at a granularity of 4k storage per bitmap bit: |
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* one peta byte storage: 1<<50 byte, 1<<38 * 4k storage blocks |
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* 1<<38 bits, |
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* 1<<23 4k bitmap pages. |
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* Use 24 bits as page index, covers 2 peta byte storage |
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* at a granularity of 4k per bit. |
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* Used to report the failed page idx on io error from the endio handlers. |
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*/ |
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#define BM_PAGE_IDX_MASK ((1UL<<24)-1) |
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/* this page is currently read in, or written back */ |
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#define BM_PAGE_IO_LOCK 31 |
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/* if there has been an IO error for this page */ |
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#define BM_PAGE_IO_ERROR 30 |
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/* this is to be able to intelligently skip disk IO, |
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* set if bits have been set since last IO. */ |
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#define BM_PAGE_NEED_WRITEOUT 29 |
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/* to mark for lazy writeout once syncer cleared all clearable bits, |
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* we if bits have been cleared since last IO. */ |
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#define BM_PAGE_LAZY_WRITEOUT 28 |
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/* pages marked with this "HINT" will be considered for writeout |
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* on activity log transactions */ |
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#define BM_PAGE_HINT_WRITEOUT 27 |
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/* store_page_idx uses non-atomic assignment. It is only used directly after |
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* allocating the page. All other bm_set_page_* and bm_clear_page_* need to |
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* use atomic bit manipulation, as set_out_of_sync (and therefore bitmap |
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* changes) may happen from various contexts, and wait_on_bit/wake_up_bit |
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* requires it all to be atomic as well. */ |
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static void bm_store_page_idx(struct page *page, unsigned long idx) |
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{ |
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BUG_ON(0 != (idx & ~BM_PAGE_IDX_MASK)); |
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set_page_private(page, idx); |
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} |
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static unsigned long bm_page_to_idx(struct page *page) |
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{ |
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return page_private(page) & BM_PAGE_IDX_MASK; |
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} |
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/* As is very unlikely that the same page is under IO from more than one |
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* context, we can get away with a bit per page and one wait queue per bitmap. |
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*/ |
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static void bm_page_lock_io(struct drbd_device *device, int page_nr) |
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{ |
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struct drbd_bitmap *b = device->bitmap; |
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void *addr = &page_private(b->bm_pages[page_nr]); |
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wait_event(b->bm_io_wait, !test_and_set_bit(BM_PAGE_IO_LOCK, addr)); |
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} |
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static void bm_page_unlock_io(struct drbd_device *device, int page_nr) |
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{ |
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struct drbd_bitmap *b = device->bitmap; |
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void *addr = &page_private(b->bm_pages[page_nr]); |
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clear_bit_unlock(BM_PAGE_IO_LOCK, addr); |
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wake_up(&device->bitmap->bm_io_wait); |
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} |
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/* set _before_ submit_io, so it may be reset due to being changed |
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* while this page is in flight... will get submitted later again */ |
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static void bm_set_page_unchanged(struct page *page) |
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{ |
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/* use cmpxchg? */ |
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clear_bit(BM_PAGE_NEED_WRITEOUT, &page_private(page)); |
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clear_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page)); |
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} |
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static void bm_set_page_need_writeout(struct page *page) |
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{ |
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set_bit(BM_PAGE_NEED_WRITEOUT, &page_private(page)); |
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} |
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void drbd_bm_reset_al_hints(struct drbd_device *device) |
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{ |
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device->bitmap->n_bitmap_hints = 0; |
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} |
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/** |
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* drbd_bm_mark_for_writeout() - mark a page with a "hint" to be considered for writeout |
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* @device: DRBD device. |
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* @page_nr: the bitmap page to mark with the "hint" flag |
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* |
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* From within an activity log transaction, we mark a few pages with these |
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* hints, then call drbd_bm_write_hinted(), which will only write out changed |
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* pages which are flagged with this mark. |
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*/ |
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void drbd_bm_mark_for_writeout(struct drbd_device *device, int page_nr) |
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{ |
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struct drbd_bitmap *b = device->bitmap; |
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struct page *page; |
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if (page_nr >= device->bitmap->bm_number_of_pages) { |
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drbd_warn(device, "BAD: page_nr: %u, number_of_pages: %u\n", |
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page_nr, (int)device->bitmap->bm_number_of_pages); |
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return; |
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} |
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page = device->bitmap->bm_pages[page_nr]; |
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BUG_ON(b->n_bitmap_hints >= ARRAY_SIZE(b->al_bitmap_hints)); |
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if (!test_and_set_bit(BM_PAGE_HINT_WRITEOUT, &page_private(page))) |
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b->al_bitmap_hints[b->n_bitmap_hints++] = page_nr; |
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} |
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static int bm_test_page_unchanged(struct page *page) |
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{ |
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volatile const unsigned long *addr = &page_private(page); |
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return (*addr & ((1UL<<BM_PAGE_NEED_WRITEOUT)|(1UL<<BM_PAGE_LAZY_WRITEOUT))) == 0; |
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} |
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static void bm_set_page_io_err(struct page *page) |
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{ |
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set_bit(BM_PAGE_IO_ERROR, &page_private(page)); |
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} |
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static void bm_clear_page_io_err(struct page *page) |
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{ |
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clear_bit(BM_PAGE_IO_ERROR, &page_private(page)); |
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} |
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static void bm_set_page_lazy_writeout(struct page *page) |
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{ |
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set_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page)); |
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} |
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static int bm_test_page_lazy_writeout(struct page *page) |
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{ |
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return test_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page)); |
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} |
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/* on a 32bit box, this would allow for exactly (2<<38) bits. */ |
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static unsigned int bm_word_to_page_idx(struct drbd_bitmap *b, unsigned long long_nr) |
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{ |
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/* page_nr = (word*sizeof(long)) >> PAGE_SHIFT; */ |
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unsigned int page_nr = long_nr >> (PAGE_SHIFT - LN2_BPL + 3); |
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BUG_ON(page_nr >= b->bm_number_of_pages); |
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return page_nr; |
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} |
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static unsigned int bm_bit_to_page_idx(struct drbd_bitmap *b, u64 bitnr) |
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{ |
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/* page_nr = (bitnr/8) >> PAGE_SHIFT; */ |
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unsigned int page_nr = bitnr >> (PAGE_SHIFT + 3); |
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BUG_ON(page_nr >= b->bm_number_of_pages); |
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return page_nr; |
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} |
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static unsigned long *__bm_map_pidx(struct drbd_bitmap *b, unsigned int idx) |
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{ |
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struct page *page = b->bm_pages[idx]; |
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return (unsigned long *) kmap_atomic(page); |
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} |
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static unsigned long *bm_map_pidx(struct drbd_bitmap *b, unsigned int idx) |
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{ |
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return __bm_map_pidx(b, idx); |
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} |
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static void __bm_unmap(unsigned long *p_addr) |
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{ |
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kunmap_atomic(p_addr); |
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}; |
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static void bm_unmap(unsigned long *p_addr) |
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{ |
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return __bm_unmap(p_addr); |
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} |
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/* long word offset of _bitmap_ sector */ |
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#define S2W(s) ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL)) |
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/* word offset from start of bitmap to word number _in_page_ |
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* modulo longs per page |
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#define MLPP(X) ((X) % (PAGE_SIZE/sizeof(long)) |
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hm, well, Philipp thinks gcc might not optimize the % into & (... - 1) |
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so do it explicitly: |
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*/ |
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#define MLPP(X) ((X) & ((PAGE_SIZE/sizeof(long))-1)) |
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/* Long words per page */ |
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#define LWPP (PAGE_SIZE/sizeof(long)) |
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/* |
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* actually most functions herein should take a struct drbd_bitmap*, not a |
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* struct drbd_device*, but for the debug macros I like to have the device around |
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* to be able to report device specific. |
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*/ |
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static void bm_free_pages(struct page **pages, unsigned long number) |
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{ |
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unsigned long i; |
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if (!pages) |
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return; |
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for (i = 0; i < number; i++) { |
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if (!pages[i]) { |
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pr_alert("bm_free_pages tried to free a NULL pointer; i=%lu n=%lu\n", |
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i, number); |
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continue; |
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} |
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__free_page(pages[i]); |
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pages[i] = NULL; |
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} |
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} |
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static inline void bm_vk_free(void *ptr) |
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{ |
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kvfree(ptr); |
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} |
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/* |
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* "have" and "want" are NUMBER OF PAGES. |
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*/ |
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static struct page **bm_realloc_pages(struct drbd_bitmap *b, unsigned long want) |
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{ |
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struct page **old_pages = b->bm_pages; |
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struct page **new_pages, *page; |
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unsigned int i, bytes; |
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unsigned long have = b->bm_number_of_pages; |
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BUG_ON(have == 0 && old_pages != NULL); |
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BUG_ON(have != 0 && old_pages == NULL); |
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if (have == want) |
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return old_pages; |
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/* Trying kmalloc first, falling back to vmalloc. |
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* GFP_NOIO, as this is called while drbd IO is "suspended", |
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* and during resize or attach on diskless Primary, |
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* we must not block on IO to ourselves. |
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* Context is receiver thread or dmsetup. */ |
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bytes = sizeof(struct page *)*want; |
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new_pages = kzalloc(bytes, GFP_NOIO | __GFP_NOWARN); |
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if (!new_pages) { |
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new_pages = __vmalloc(bytes, GFP_NOIO | __GFP_ZERO); |
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if (!new_pages) |
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return NULL; |
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} |
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if (want >= have) { |
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for (i = 0; i < have; i++) |
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new_pages[i] = old_pages[i]; |
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for (; i < want; i++) { |
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page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); |
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if (!page) { |
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bm_free_pages(new_pages + have, i - have); |
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bm_vk_free(new_pages); |
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return NULL; |
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} |
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/* we want to know which page it is |
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* from the endio handlers */ |
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bm_store_page_idx(page, i); |
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new_pages[i] = page; |
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} |
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} else { |
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for (i = 0; i < want; i++) |
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new_pages[i] = old_pages[i]; |
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/* NOT HERE, we are outside the spinlock! |
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bm_free_pages(old_pages + want, have - want); |
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*/ |
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} |
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return new_pages; |
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} |
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/* |
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* allocates the drbd_bitmap and stores it in device->bitmap. |
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*/ |
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int drbd_bm_init(struct drbd_device *device) |
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{ |
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struct drbd_bitmap *b = device->bitmap; |
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WARN_ON(b != NULL); |
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b = kzalloc(sizeof(struct drbd_bitmap), GFP_KERNEL); |
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if (!b) |
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return -ENOMEM; |
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spin_lock_init(&b->bm_lock); |
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mutex_init(&b->bm_change); |
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init_waitqueue_head(&b->bm_io_wait); |
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device->bitmap = b; |
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return 0; |
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} |
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sector_t drbd_bm_capacity(struct drbd_device *device) |
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{ |
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if (!expect(device->bitmap)) |
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return 0; |
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return device->bitmap->bm_dev_capacity; |
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} |
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/* called on driver unload. TODO: call when a device is destroyed. |
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*/ |
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void drbd_bm_cleanup(struct drbd_device *device) |
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{ |
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if (!expect(device->bitmap)) |
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return; |
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bm_free_pages(device->bitmap->bm_pages, device->bitmap->bm_number_of_pages); |
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bm_vk_free(device->bitmap->bm_pages); |
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kfree(device->bitmap); |
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device->bitmap = NULL; |
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} |
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|
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/* |
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* since (b->bm_bits % BITS_PER_LONG) != 0, |
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* this masks out the remaining bits. |
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* Returns the number of bits cleared. |
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*/ |
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#ifndef BITS_PER_PAGE |
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#define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3)) |
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#define BITS_PER_PAGE_MASK (BITS_PER_PAGE - 1) |
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#else |
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# if BITS_PER_PAGE != (1UL << (PAGE_SHIFT + 3)) |
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# error "ambiguous BITS_PER_PAGE" |
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# endif |
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#endif |
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#define BITS_PER_LONG_MASK (BITS_PER_LONG - 1) |
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static int bm_clear_surplus(struct drbd_bitmap *b) |
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{ |
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unsigned long mask; |
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unsigned long *p_addr, *bm; |
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int tmp; |
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int cleared = 0; |
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|
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/* number of bits modulo bits per page */ |
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tmp = (b->bm_bits & BITS_PER_PAGE_MASK); |
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/* mask the used bits of the word containing the last bit */ |
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mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1; |
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/* bitmap is always stored little endian, |
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* on disk and in core memory alike */ |
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mask = cpu_to_lel(mask); |
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|
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p_addr = bm_map_pidx(b, b->bm_number_of_pages - 1); |
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bm = p_addr + (tmp/BITS_PER_LONG); |
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if (mask) { |
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/* If mask != 0, we are not exactly aligned, so bm now points |
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* to the long containing the last bit. |
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* If mask == 0, bm already points to the word immediately |
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* after the last (long word aligned) bit. */ |
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cleared = hweight_long(*bm & ~mask); |
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*bm &= mask; |
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bm++; |
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} |
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|
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if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) { |
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/* on a 32bit arch, we may need to zero out |
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* a padding long to align with a 64bit remote */ |
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cleared += hweight_long(*bm); |
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*bm = 0; |
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} |
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bm_unmap(p_addr); |
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return cleared; |
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} |
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|
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static void bm_set_surplus(struct drbd_bitmap *b) |
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{ |
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unsigned long mask; |
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unsigned long *p_addr, *bm; |
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int tmp; |
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|
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/* number of bits modulo bits per page */ |
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tmp = (b->bm_bits & BITS_PER_PAGE_MASK); |
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/* mask the used bits of the word containing the last bit */ |
|
mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1; |
|
/* bitmap is always stored little endian, |
|
* on disk and in core memory alike */ |
|
mask = cpu_to_lel(mask); |
|
|
|
p_addr = bm_map_pidx(b, b->bm_number_of_pages - 1); |
|
bm = p_addr + (tmp/BITS_PER_LONG); |
|
if (mask) { |
|
/* If mask != 0, we are not exactly aligned, so bm now points |
|
* to the long containing the last bit. |
|
* If mask == 0, bm already points to the word immediately |
|
* after the last (long word aligned) bit. */ |
|
*bm |= ~mask; |
|
bm++; |
|
} |
|
|
|
if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) { |
|
/* on a 32bit arch, we may need to zero out |
|
* a padding long to align with a 64bit remote */ |
|
*bm = ~0UL; |
|
} |
|
bm_unmap(p_addr); |
|
} |
|
|
|
/* you better not modify the bitmap while this is running, |
|
* or its results will be stale */ |
|
static unsigned long bm_count_bits(struct drbd_bitmap *b) |
|
{ |
|
unsigned long *p_addr; |
|
unsigned long bits = 0; |
|
unsigned long mask = (1UL << (b->bm_bits & BITS_PER_LONG_MASK)) -1; |
|
int idx, last_word; |
|
|
|
/* all but last page */ |
|
for (idx = 0; idx < b->bm_number_of_pages - 1; idx++) { |
|
p_addr = __bm_map_pidx(b, idx); |
|
bits += bitmap_weight(p_addr, BITS_PER_PAGE); |
|
__bm_unmap(p_addr); |
|
cond_resched(); |
|
} |
|
/* last (or only) page */ |
|
last_word = ((b->bm_bits - 1) & BITS_PER_PAGE_MASK) >> LN2_BPL; |
|
p_addr = __bm_map_pidx(b, idx); |
|
bits += bitmap_weight(p_addr, last_word * BITS_PER_LONG); |
|
p_addr[last_word] &= cpu_to_lel(mask); |
|
bits += hweight_long(p_addr[last_word]); |
|
/* 32bit arch, may have an unused padding long */ |
|
if (BITS_PER_LONG == 32 && (last_word & 1) == 0) |
|
p_addr[last_word+1] = 0; |
|
__bm_unmap(p_addr); |
|
return bits; |
|
} |
|
|
|
/* offset and len in long words.*/ |
|
static void bm_memset(struct drbd_bitmap *b, size_t offset, int c, size_t len) |
|
{ |
|
unsigned long *p_addr, *bm; |
|
unsigned int idx; |
|
size_t do_now, end; |
|
|
|
end = offset + len; |
|
|
|
if (end > b->bm_words) { |
|
pr_alert("bm_memset end > bm_words\n"); |
|
return; |
|
} |
|
|
|
while (offset < end) { |
|
do_now = min_t(size_t, ALIGN(offset + 1, LWPP), end) - offset; |
|
idx = bm_word_to_page_idx(b, offset); |
|
p_addr = bm_map_pidx(b, idx); |
|
bm = p_addr + MLPP(offset); |
|
if (bm+do_now > p_addr + LWPP) { |
|
pr_alert("BUG BUG BUG! p_addr:%p bm:%p do_now:%d\n", |
|
p_addr, bm, (int)do_now); |
|
} else |
|
memset(bm, c, do_now * sizeof(long)); |
|
bm_unmap(p_addr); |
|
bm_set_page_need_writeout(b->bm_pages[idx]); |
|
offset += do_now; |
|
} |
|
} |
|
|
|
/* For the layout, see comment above drbd_md_set_sector_offsets(). */ |
|
static u64 drbd_md_on_disk_bits(struct drbd_backing_dev *ldev) |
|
{ |
|
u64 bitmap_sectors; |
|
if (ldev->md.al_offset == 8) |
|
bitmap_sectors = ldev->md.md_size_sect - ldev->md.bm_offset; |
|
else |
|
bitmap_sectors = ldev->md.al_offset - ldev->md.bm_offset; |
|
return bitmap_sectors << (9 + 3); |
|
} |
|
|
|
/* |
|
* make sure the bitmap has enough room for the attached storage, |
|
* if necessary, resize. |
|
* called whenever we may have changed the device size. |
|
* returns -ENOMEM if we could not allocate enough memory, 0 on success. |
|
* In case this is actually a resize, we copy the old bitmap into the new one. |
|
* Otherwise, the bitmap is initialized to all bits set. |
|
*/ |
|
int drbd_bm_resize(struct drbd_device *device, sector_t capacity, int set_new_bits) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long bits, words, owords, obits; |
|
unsigned long want, have, onpages; /* number of pages */ |
|
struct page **npages, **opages = NULL; |
|
int err = 0; |
|
bool growing; |
|
|
|
if (!expect(b)) |
|
return -ENOMEM; |
|
|
|
drbd_bm_lock(device, "resize", BM_LOCKED_MASK); |
|
|
|
drbd_info(device, "drbd_bm_resize called with capacity == %llu\n", |
|
(unsigned long long)capacity); |
|
|
|
if (capacity == b->bm_dev_capacity) |
|
goto out; |
|
|
|
if (capacity == 0) { |
|
spin_lock_irq(&b->bm_lock); |
|
opages = b->bm_pages; |
|
onpages = b->bm_number_of_pages; |
|
owords = b->bm_words; |
|
b->bm_pages = NULL; |
|
b->bm_number_of_pages = |
|
b->bm_set = |
|
b->bm_bits = |
|
b->bm_words = |
|
b->bm_dev_capacity = 0; |
|
spin_unlock_irq(&b->bm_lock); |
|
bm_free_pages(opages, onpages); |
|
bm_vk_free(opages); |
|
goto out; |
|
} |
|
bits = BM_SECT_TO_BIT(ALIGN(capacity, BM_SECT_PER_BIT)); |
|
|
|
/* if we would use |
|
words = ALIGN(bits,BITS_PER_LONG) >> LN2_BPL; |
|
a 32bit host could present the wrong number of words |
|
to a 64bit host. |
|
*/ |
|
words = ALIGN(bits, 64) >> LN2_BPL; |
|
|
|
if (get_ldev(device)) { |
|
u64 bits_on_disk = drbd_md_on_disk_bits(device->ldev); |
|
put_ldev(device); |
|
if (bits > bits_on_disk) { |
|
drbd_info(device, "bits = %lu\n", bits); |
|
drbd_info(device, "bits_on_disk = %llu\n", bits_on_disk); |
|
err = -ENOSPC; |
|
goto out; |
|
} |
|
} |
|
|
|
want = ALIGN(words*sizeof(long), PAGE_SIZE) >> PAGE_SHIFT; |
|
have = b->bm_number_of_pages; |
|
if (want == have) { |
|
D_ASSERT(device, b->bm_pages != NULL); |
|
npages = b->bm_pages; |
|
} else { |
|
if (drbd_insert_fault(device, DRBD_FAULT_BM_ALLOC)) |
|
npages = NULL; |
|
else |
|
npages = bm_realloc_pages(b, want); |
|
} |
|
|
|
if (!npages) { |
|
err = -ENOMEM; |
|
goto out; |
|
} |
|
|
|
spin_lock_irq(&b->bm_lock); |
|
opages = b->bm_pages; |
|
owords = b->bm_words; |
|
obits = b->bm_bits; |
|
|
|
growing = bits > obits; |
|
if (opages && growing && set_new_bits) |
|
bm_set_surplus(b); |
|
|
|
b->bm_pages = npages; |
|
b->bm_number_of_pages = want; |
|
b->bm_bits = bits; |
|
b->bm_words = words; |
|
b->bm_dev_capacity = capacity; |
|
|
|
if (growing) { |
|
if (set_new_bits) { |
|
bm_memset(b, owords, 0xff, words-owords); |
|
b->bm_set += bits - obits; |
|
} else |
|
bm_memset(b, owords, 0x00, words-owords); |
|
|
|
} |
|
|
|
if (want < have) { |
|
/* implicit: (opages != NULL) && (opages != npages) */ |
|
bm_free_pages(opages + want, have - want); |
|
} |
|
|
|
(void)bm_clear_surplus(b); |
|
|
|
spin_unlock_irq(&b->bm_lock); |
|
if (opages != npages) |
|
bm_vk_free(opages); |
|
if (!growing) |
|
b->bm_set = bm_count_bits(b); |
|
drbd_info(device, "resync bitmap: bits=%lu words=%lu pages=%lu\n", bits, words, want); |
|
|
|
out: |
|
drbd_bm_unlock(device); |
|
return err; |
|
} |
|
|
|
/* inherently racy: |
|
* if not protected by other means, return value may be out of date when |
|
* leaving this function... |
|
* we still need to lock it, since it is important that this returns |
|
* bm_set == 0 precisely. |
|
* |
|
* maybe bm_set should be atomic_t ? |
|
*/ |
|
unsigned long _drbd_bm_total_weight(struct drbd_device *device) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long s; |
|
unsigned long flags; |
|
|
|
if (!expect(b)) |
|
return 0; |
|
if (!expect(b->bm_pages)) |
|
return 0; |
|
|
|
spin_lock_irqsave(&b->bm_lock, flags); |
|
s = b->bm_set; |
|
spin_unlock_irqrestore(&b->bm_lock, flags); |
|
|
|
return s; |
|
} |
|
|
|
unsigned long drbd_bm_total_weight(struct drbd_device *device) |
|
{ |
|
unsigned long s; |
|
/* if I don't have a disk, I don't know about out-of-sync status */ |
|
if (!get_ldev_if_state(device, D_NEGOTIATING)) |
|
return 0; |
|
s = _drbd_bm_total_weight(device); |
|
put_ldev(device); |
|
return s; |
|
} |
|
|
|
size_t drbd_bm_words(struct drbd_device *device) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
if (!expect(b)) |
|
return 0; |
|
if (!expect(b->bm_pages)) |
|
return 0; |
|
|
|
return b->bm_words; |
|
} |
|
|
|
unsigned long drbd_bm_bits(struct drbd_device *device) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
if (!expect(b)) |
|
return 0; |
|
|
|
return b->bm_bits; |
|
} |
|
|
|
/* merge number words from buffer into the bitmap starting at offset. |
|
* buffer[i] is expected to be little endian unsigned long. |
|
* bitmap must be locked by drbd_bm_lock. |
|
* currently only used from receive_bitmap. |
|
*/ |
|
void drbd_bm_merge_lel(struct drbd_device *device, size_t offset, size_t number, |
|
unsigned long *buffer) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long *p_addr, *bm; |
|
unsigned long word, bits; |
|
unsigned int idx; |
|
size_t end, do_now; |
|
|
|
end = offset + number; |
|
|
|
if (!expect(b)) |
|
return; |
|
if (!expect(b->bm_pages)) |
|
return; |
|
if (number == 0) |
|
return; |
|
WARN_ON(offset >= b->bm_words); |
|
WARN_ON(end > b->bm_words); |
|
|
|
spin_lock_irq(&b->bm_lock); |
|
while (offset < end) { |
|
do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset; |
|
idx = bm_word_to_page_idx(b, offset); |
|
p_addr = bm_map_pidx(b, idx); |
|
bm = p_addr + MLPP(offset); |
|
offset += do_now; |
|
while (do_now--) { |
|
bits = hweight_long(*bm); |
|
word = *bm | *buffer++; |
|
*bm++ = word; |
|
b->bm_set += hweight_long(word) - bits; |
|
} |
|
bm_unmap(p_addr); |
|
bm_set_page_need_writeout(b->bm_pages[idx]); |
|
} |
|
/* with 32bit <-> 64bit cross-platform connect |
|
* this is only correct for current usage, |
|
* where we _know_ that we are 64 bit aligned, |
|
* and know that this function is used in this way, too... |
|
*/ |
|
if (end == b->bm_words) |
|
b->bm_set -= bm_clear_surplus(b); |
|
spin_unlock_irq(&b->bm_lock); |
|
} |
|
|
|
/* copy number words from the bitmap starting at offset into the buffer. |
|
* buffer[i] will be little endian unsigned long. |
|
*/ |
|
void drbd_bm_get_lel(struct drbd_device *device, size_t offset, size_t number, |
|
unsigned long *buffer) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long *p_addr, *bm; |
|
size_t end, do_now; |
|
|
|
end = offset + number; |
|
|
|
if (!expect(b)) |
|
return; |
|
if (!expect(b->bm_pages)) |
|
return; |
|
|
|
spin_lock_irq(&b->bm_lock); |
|
if ((offset >= b->bm_words) || |
|
(end > b->bm_words) || |
|
(number <= 0)) |
|
drbd_err(device, "offset=%lu number=%lu bm_words=%lu\n", |
|
(unsigned long) offset, |
|
(unsigned long) number, |
|
(unsigned long) b->bm_words); |
|
else { |
|
while (offset < end) { |
|
do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset; |
|
p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, offset)); |
|
bm = p_addr + MLPP(offset); |
|
offset += do_now; |
|
while (do_now--) |
|
*buffer++ = *bm++; |
|
bm_unmap(p_addr); |
|
} |
|
} |
|
spin_unlock_irq(&b->bm_lock); |
|
} |
|
|
|
/* set all bits in the bitmap */ |
|
void drbd_bm_set_all(struct drbd_device *device) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
if (!expect(b)) |
|
return; |
|
if (!expect(b->bm_pages)) |
|
return; |
|
|
|
spin_lock_irq(&b->bm_lock); |
|
bm_memset(b, 0, 0xff, b->bm_words); |
|
(void)bm_clear_surplus(b); |
|
b->bm_set = b->bm_bits; |
|
spin_unlock_irq(&b->bm_lock); |
|
} |
|
|
|
/* clear all bits in the bitmap */ |
|
void drbd_bm_clear_all(struct drbd_device *device) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
if (!expect(b)) |
|
return; |
|
if (!expect(b->bm_pages)) |
|
return; |
|
|
|
spin_lock_irq(&b->bm_lock); |
|
bm_memset(b, 0, 0, b->bm_words); |
|
b->bm_set = 0; |
|
spin_unlock_irq(&b->bm_lock); |
|
} |
|
|
|
static void drbd_bm_aio_ctx_destroy(struct kref *kref) |
|
{ |
|
struct drbd_bm_aio_ctx *ctx = container_of(kref, struct drbd_bm_aio_ctx, kref); |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&ctx->device->resource->req_lock, flags); |
|
list_del(&ctx->list); |
|
spin_unlock_irqrestore(&ctx->device->resource->req_lock, flags); |
|
put_ldev(ctx->device); |
|
kfree(ctx); |
|
} |
|
|
|
/* bv_page may be a copy, or may be the original */ |
|
static void drbd_bm_endio(struct bio *bio) |
|
{ |
|
struct drbd_bm_aio_ctx *ctx = bio->bi_private; |
|
struct drbd_device *device = ctx->device; |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned int idx = bm_page_to_idx(bio_first_page_all(bio)); |
|
|
|
if ((ctx->flags & BM_AIO_COPY_PAGES) == 0 && |
|
!bm_test_page_unchanged(b->bm_pages[idx])) |
|
drbd_warn(device, "bitmap page idx %u changed during IO!\n", idx); |
|
|
|
if (bio->bi_status) { |
|
/* ctx error will hold the completed-last non-zero error code, |
|
* in case error codes differ. */ |
|
ctx->error = blk_status_to_errno(bio->bi_status); |
|
bm_set_page_io_err(b->bm_pages[idx]); |
|
/* Not identical to on disk version of it. |
|
* Is BM_PAGE_IO_ERROR enough? */ |
|
if (__ratelimit(&drbd_ratelimit_state)) |
|
drbd_err(device, "IO ERROR %d on bitmap page idx %u\n", |
|
bio->bi_status, idx); |
|
} else { |
|
bm_clear_page_io_err(b->bm_pages[idx]); |
|
dynamic_drbd_dbg(device, "bitmap page idx %u completed\n", idx); |
|
} |
|
|
|
bm_page_unlock_io(device, idx); |
|
|
|
if (ctx->flags & BM_AIO_COPY_PAGES) |
|
mempool_free(bio->bi_io_vec[0].bv_page, &drbd_md_io_page_pool); |
|
|
|
bio_put(bio); |
|
|
|
if (atomic_dec_and_test(&ctx->in_flight)) { |
|
ctx->done = 1; |
|
wake_up(&device->misc_wait); |
|
kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy); |
|
} |
|
} |
|
|
|
static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_hold(local) |
|
{ |
|
struct bio *bio = bio_alloc_bioset(GFP_NOIO, 1, &drbd_md_io_bio_set); |
|
struct drbd_device *device = ctx->device; |
|
struct drbd_bitmap *b = device->bitmap; |
|
struct page *page; |
|
unsigned int len; |
|
unsigned int op = (ctx->flags & BM_AIO_READ) ? REQ_OP_READ : REQ_OP_WRITE; |
|
|
|
sector_t on_disk_sector = |
|
device->ldev->md.md_offset + device->ldev->md.bm_offset; |
|
on_disk_sector += ((sector_t)page_nr) << (PAGE_SHIFT-9); |
|
|
|
/* this might happen with very small |
|
* flexible external meta data device, |
|
* or with PAGE_SIZE > 4k */ |
|
len = min_t(unsigned int, PAGE_SIZE, |
|
(drbd_md_last_sector(device->ldev) - on_disk_sector + 1)<<9); |
|
|
|
/* serialize IO on this page */ |
|
bm_page_lock_io(device, page_nr); |
|
/* before memcpy and submit, |
|
* so it can be redirtied any time */ |
|
bm_set_page_unchanged(b->bm_pages[page_nr]); |
|
|
|
if (ctx->flags & BM_AIO_COPY_PAGES) { |
|
page = mempool_alloc(&drbd_md_io_page_pool, |
|
GFP_NOIO | __GFP_HIGHMEM); |
|
copy_highpage(page, b->bm_pages[page_nr]); |
|
bm_store_page_idx(page, page_nr); |
|
} else |
|
page = b->bm_pages[page_nr]; |
|
bio_set_dev(bio, device->ldev->md_bdev); |
|
bio->bi_iter.bi_sector = on_disk_sector; |
|
/* bio_add_page of a single page to an empty bio will always succeed, |
|
* according to api. Do we want to assert that? */ |
|
bio_add_page(bio, page, len, 0); |
|
bio->bi_private = ctx; |
|
bio->bi_end_io = drbd_bm_endio; |
|
bio_set_op_attrs(bio, op, 0); |
|
|
|
if (drbd_insert_fault(device, (op == REQ_OP_WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) { |
|
bio_io_error(bio); |
|
} else { |
|
submit_bio(bio); |
|
/* this should not count as user activity and cause the |
|
* resync to throttle -- see drbd_rs_should_slow_down(). */ |
|
atomic_add(len >> 9, &device->rs_sect_ev); |
|
} |
|
} |
|
|
|
/* |
|
* bm_rw: read/write the whole bitmap from/to its on disk location. |
|
*/ |
|
static int bm_rw(struct drbd_device *device, const unsigned int flags, unsigned lazy_writeout_upper_idx) __must_hold(local) |
|
{ |
|
struct drbd_bm_aio_ctx *ctx; |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned int num_pages, i, count = 0; |
|
unsigned long now; |
|
char ppb[10]; |
|
int err = 0; |
|
|
|
/* |
|
* We are protected against bitmap disappearing/resizing by holding an |
|
* ldev reference (caller must have called get_ldev()). |
|
* For read/write, we are protected against changes to the bitmap by |
|
* the bitmap lock (see drbd_bitmap_io). |
|
* For lazy writeout, we don't care for ongoing changes to the bitmap, |
|
* as we submit copies of pages anyways. |
|
*/ |
|
|
|
ctx = kmalloc(sizeof(struct drbd_bm_aio_ctx), GFP_NOIO); |
|
if (!ctx) |
|
return -ENOMEM; |
|
|
|
*ctx = (struct drbd_bm_aio_ctx) { |
|
.device = device, |
|
.start_jif = jiffies, |
|
.in_flight = ATOMIC_INIT(1), |
|
.done = 0, |
|
.flags = flags, |
|
.error = 0, |
|
.kref = KREF_INIT(2), |
|
}; |
|
|
|
if (!get_ldev_if_state(device, D_ATTACHING)) { /* put is in drbd_bm_aio_ctx_destroy() */ |
|
drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in bm_rw()\n"); |
|
kfree(ctx); |
|
return -ENODEV; |
|
} |
|
/* Here D_ATTACHING is sufficient since drbd_bm_read() is called only from |
|
drbd_adm_attach(), after device->ldev was assigned. */ |
|
|
|
if (0 == (ctx->flags & ~BM_AIO_READ)) |
|
WARN_ON(!(BM_LOCKED_MASK & b->bm_flags)); |
|
|
|
spin_lock_irq(&device->resource->req_lock); |
|
list_add_tail(&ctx->list, &device->pending_bitmap_io); |
|
spin_unlock_irq(&device->resource->req_lock); |
|
|
|
num_pages = b->bm_number_of_pages; |
|
|
|
now = jiffies; |
|
|
|
/* let the layers below us try to merge these bios... */ |
|
|
|
if (flags & BM_AIO_READ) { |
|
for (i = 0; i < num_pages; i++) { |
|
atomic_inc(&ctx->in_flight); |
|
bm_page_io_async(ctx, i); |
|
++count; |
|
cond_resched(); |
|
} |
|
} else if (flags & BM_AIO_WRITE_HINTED) { |
|
/* ASSERT: BM_AIO_WRITE_ALL_PAGES is not set. */ |
|
unsigned int hint; |
|
for (hint = 0; hint < b->n_bitmap_hints; hint++) { |
|
i = b->al_bitmap_hints[hint]; |
|
if (i >= num_pages) /* == -1U: no hint here. */ |
|
continue; |
|
/* Several AL-extents may point to the same page. */ |
|
if (!test_and_clear_bit(BM_PAGE_HINT_WRITEOUT, |
|
&page_private(b->bm_pages[i]))) |
|
continue; |
|
/* Has it even changed? */ |
|
if (bm_test_page_unchanged(b->bm_pages[i])) |
|
continue; |
|
atomic_inc(&ctx->in_flight); |
|
bm_page_io_async(ctx, i); |
|
++count; |
|
} |
|
} else { |
|
for (i = 0; i < num_pages; i++) { |
|
/* ignore completely unchanged pages */ |
|
if (lazy_writeout_upper_idx && i == lazy_writeout_upper_idx) |
|
break; |
|
if (!(flags & BM_AIO_WRITE_ALL_PAGES) && |
|
bm_test_page_unchanged(b->bm_pages[i])) { |
|
dynamic_drbd_dbg(device, "skipped bm write for idx %u\n", i); |
|
continue; |
|
} |
|
/* during lazy writeout, |
|
* ignore those pages not marked for lazy writeout. */ |
|
if (lazy_writeout_upper_idx && |
|
!bm_test_page_lazy_writeout(b->bm_pages[i])) { |
|
dynamic_drbd_dbg(device, "skipped bm lazy write for idx %u\n", i); |
|
continue; |
|
} |
|
atomic_inc(&ctx->in_flight); |
|
bm_page_io_async(ctx, i); |
|
++count; |
|
cond_resched(); |
|
} |
|
} |
|
|
|
/* |
|
* We initialize ctx->in_flight to one to make sure drbd_bm_endio |
|
* will not set ctx->done early, and decrement / test it here. If there |
|
* are still some bios in flight, we need to wait for them here. |
|
* If all IO is done already (or nothing had been submitted), there is |
|
* no need to wait. Still, we need to put the kref associated with the |
|
* "in_flight reached zero, all done" event. |
|
*/ |
|
if (!atomic_dec_and_test(&ctx->in_flight)) |
|
wait_until_done_or_force_detached(device, device->ldev, &ctx->done); |
|
else |
|
kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy); |
|
|
|
/* summary for global bitmap IO */ |
|
if (flags == 0) { |
|
unsigned int ms = jiffies_to_msecs(jiffies - now); |
|
if (ms > 5) { |
|
drbd_info(device, "bitmap %s of %u pages took %u ms\n", |
|
(flags & BM_AIO_READ) ? "READ" : "WRITE", |
|
count, ms); |
|
} |
|
} |
|
|
|
if (ctx->error) { |
|
drbd_alert(device, "we had at least one MD IO ERROR during bitmap IO\n"); |
|
drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR); |
|
err = -EIO; /* ctx->error ? */ |
|
} |
|
|
|
if (atomic_read(&ctx->in_flight)) |
|
err = -EIO; /* Disk timeout/force-detach during IO... */ |
|
|
|
now = jiffies; |
|
if (flags & BM_AIO_READ) { |
|
b->bm_set = bm_count_bits(b); |
|
drbd_info(device, "recounting of set bits took additional %lu jiffies\n", |
|
jiffies - now); |
|
} |
|
now = b->bm_set; |
|
|
|
if ((flags & ~BM_AIO_READ) == 0) |
|
drbd_info(device, "%s (%lu bits) marked out-of-sync by on disk bit-map.\n", |
|
ppsize(ppb, now << (BM_BLOCK_SHIFT-10)), now); |
|
|
|
kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy); |
|
return err; |
|
} |
|
|
|
/** |
|
* drbd_bm_read() - Read the whole bitmap from its on disk location. |
|
* @device: DRBD device. |
|
*/ |
|
int drbd_bm_read(struct drbd_device *device) __must_hold(local) |
|
{ |
|
return bm_rw(device, BM_AIO_READ, 0); |
|
} |
|
|
|
/** |
|
* drbd_bm_write() - Write the whole bitmap to its on disk location. |
|
* @device: DRBD device. |
|
* |
|
* Will only write pages that have changed since last IO. |
|
*/ |
|
int drbd_bm_write(struct drbd_device *device) __must_hold(local) |
|
{ |
|
return bm_rw(device, 0, 0); |
|
} |
|
|
|
/** |
|
* drbd_bm_write_all() - Write the whole bitmap to its on disk location. |
|
* @device: DRBD device. |
|
* |
|
* Will write all pages. |
|
*/ |
|
int drbd_bm_write_all(struct drbd_device *device) __must_hold(local) |
|
{ |
|
return bm_rw(device, BM_AIO_WRITE_ALL_PAGES, 0); |
|
} |
|
|
|
/** |
|
* drbd_bm_write_lazy() - Write bitmap pages 0 to @upper_idx-1, if they have changed. |
|
* @device: DRBD device. |
|
* @upper_idx: 0: write all changed pages; +ve: page index to stop scanning for changed pages |
|
*/ |
|
int drbd_bm_write_lazy(struct drbd_device *device, unsigned upper_idx) __must_hold(local) |
|
{ |
|
return bm_rw(device, BM_AIO_COPY_PAGES, upper_idx); |
|
} |
|
|
|
/** |
|
* drbd_bm_write_copy_pages() - Write the whole bitmap to its on disk location. |
|
* @device: DRBD device. |
|
* |
|
* Will only write pages that have changed since last IO. |
|
* In contrast to drbd_bm_write(), this will copy the bitmap pages |
|
* to temporary writeout pages. It is intended to trigger a full write-out |
|
* while still allowing the bitmap to change, for example if a resync or online |
|
* verify is aborted due to a failed peer disk, while local IO continues, or |
|
* pending resync acks are still being processed. |
|
*/ |
|
int drbd_bm_write_copy_pages(struct drbd_device *device) __must_hold(local) |
|
{ |
|
return bm_rw(device, BM_AIO_COPY_PAGES, 0); |
|
} |
|
|
|
/** |
|
* drbd_bm_write_hinted() - Write bitmap pages with "hint" marks, if they have changed. |
|
* @device: DRBD device. |
|
*/ |
|
int drbd_bm_write_hinted(struct drbd_device *device) __must_hold(local) |
|
{ |
|
return bm_rw(device, BM_AIO_WRITE_HINTED | BM_AIO_COPY_PAGES, 0); |
|
} |
|
|
|
/* NOTE |
|
* find_first_bit returns int, we return unsigned long. |
|
* For this to work on 32bit arch with bitnumbers > (1<<32), |
|
* we'd need to return u64, and get a whole lot of other places |
|
* fixed where we still use unsigned long. |
|
* |
|
* this returns a bit number, NOT a sector! |
|
*/ |
|
static unsigned long __bm_find_next(struct drbd_device *device, unsigned long bm_fo, |
|
const int find_zero_bit) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long *p_addr; |
|
unsigned long bit_offset; |
|
unsigned i; |
|
|
|
|
|
if (bm_fo > b->bm_bits) { |
|
drbd_err(device, "bm_fo=%lu bm_bits=%lu\n", bm_fo, b->bm_bits); |
|
bm_fo = DRBD_END_OF_BITMAP; |
|
} else { |
|
while (bm_fo < b->bm_bits) { |
|
/* bit offset of the first bit in the page */ |
|
bit_offset = bm_fo & ~BITS_PER_PAGE_MASK; |
|
p_addr = __bm_map_pidx(b, bm_bit_to_page_idx(b, bm_fo)); |
|
|
|
if (find_zero_bit) |
|
i = find_next_zero_bit_le(p_addr, |
|
PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK); |
|
else |
|
i = find_next_bit_le(p_addr, |
|
PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK); |
|
|
|
__bm_unmap(p_addr); |
|
if (i < PAGE_SIZE*8) { |
|
bm_fo = bit_offset + i; |
|
if (bm_fo >= b->bm_bits) |
|
break; |
|
goto found; |
|
} |
|
bm_fo = bit_offset + PAGE_SIZE*8; |
|
} |
|
bm_fo = DRBD_END_OF_BITMAP; |
|
} |
|
found: |
|
return bm_fo; |
|
} |
|
|
|
static unsigned long bm_find_next(struct drbd_device *device, |
|
unsigned long bm_fo, const int find_zero_bit) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long i = DRBD_END_OF_BITMAP; |
|
|
|
if (!expect(b)) |
|
return i; |
|
if (!expect(b->bm_pages)) |
|
return i; |
|
|
|
spin_lock_irq(&b->bm_lock); |
|
if (BM_DONT_TEST & b->bm_flags) |
|
bm_print_lock_info(device); |
|
|
|
i = __bm_find_next(device, bm_fo, find_zero_bit); |
|
|
|
spin_unlock_irq(&b->bm_lock); |
|
return i; |
|
} |
|
|
|
unsigned long drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo) |
|
{ |
|
return bm_find_next(device, bm_fo, 0); |
|
} |
|
|
|
#if 0 |
|
/* not yet needed for anything. */ |
|
unsigned long drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo) |
|
{ |
|
return bm_find_next(device, bm_fo, 1); |
|
} |
|
#endif |
|
|
|
/* does not spin_lock_irqsave. |
|
* you must take drbd_bm_lock() first */ |
|
unsigned long _drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo) |
|
{ |
|
/* WARN_ON(!(BM_DONT_SET & device->b->bm_flags)); */ |
|
return __bm_find_next(device, bm_fo, 0); |
|
} |
|
|
|
unsigned long _drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo) |
|
{ |
|
/* WARN_ON(!(BM_DONT_SET & device->b->bm_flags)); */ |
|
return __bm_find_next(device, bm_fo, 1); |
|
} |
|
|
|
/* returns number of bits actually changed. |
|
* for val != 0, we change 0 -> 1, return code positive |
|
* for val == 0, we change 1 -> 0, return code negative |
|
* wants bitnr, not sector. |
|
* expected to be called for only a few bits (e - s about BITS_PER_LONG). |
|
* Must hold bitmap lock already. */ |
|
static int __bm_change_bits_to(struct drbd_device *device, const unsigned long s, |
|
unsigned long e, int val) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long *p_addr = NULL; |
|
unsigned long bitnr; |
|
unsigned int last_page_nr = -1U; |
|
int c = 0; |
|
int changed_total = 0; |
|
|
|
if (e >= b->bm_bits) { |
|
drbd_err(device, "ASSERT FAILED: bit_s=%lu bit_e=%lu bm_bits=%lu\n", |
|
s, e, b->bm_bits); |
|
e = b->bm_bits ? b->bm_bits -1 : 0; |
|
} |
|
for (bitnr = s; bitnr <= e; bitnr++) { |
|
unsigned int page_nr = bm_bit_to_page_idx(b, bitnr); |
|
if (page_nr != last_page_nr) { |
|
if (p_addr) |
|
__bm_unmap(p_addr); |
|
if (c < 0) |
|
bm_set_page_lazy_writeout(b->bm_pages[last_page_nr]); |
|
else if (c > 0) |
|
bm_set_page_need_writeout(b->bm_pages[last_page_nr]); |
|
changed_total += c; |
|
c = 0; |
|
p_addr = __bm_map_pidx(b, page_nr); |
|
last_page_nr = page_nr; |
|
} |
|
if (val) |
|
c += (0 == __test_and_set_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr)); |
|
else |
|
c -= (0 != __test_and_clear_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr)); |
|
} |
|
if (p_addr) |
|
__bm_unmap(p_addr); |
|
if (c < 0) |
|
bm_set_page_lazy_writeout(b->bm_pages[last_page_nr]); |
|
else if (c > 0) |
|
bm_set_page_need_writeout(b->bm_pages[last_page_nr]); |
|
changed_total += c; |
|
b->bm_set += changed_total; |
|
return changed_total; |
|
} |
|
|
|
/* returns number of bits actually changed. |
|
* for val != 0, we change 0 -> 1, return code positive |
|
* for val == 0, we change 1 -> 0, return code negative |
|
* wants bitnr, not sector */ |
|
static int bm_change_bits_to(struct drbd_device *device, const unsigned long s, |
|
const unsigned long e, int val) |
|
{ |
|
unsigned long flags; |
|
struct drbd_bitmap *b = device->bitmap; |
|
int c = 0; |
|
|
|
if (!expect(b)) |
|
return 1; |
|
if (!expect(b->bm_pages)) |
|
return 0; |
|
|
|
spin_lock_irqsave(&b->bm_lock, flags); |
|
if ((val ? BM_DONT_SET : BM_DONT_CLEAR) & b->bm_flags) |
|
bm_print_lock_info(device); |
|
|
|
c = __bm_change_bits_to(device, s, e, val); |
|
|
|
spin_unlock_irqrestore(&b->bm_lock, flags); |
|
return c; |
|
} |
|
|
|
/* returns number of bits changed 0 -> 1 */ |
|
int drbd_bm_set_bits(struct drbd_device *device, const unsigned long s, const unsigned long e) |
|
{ |
|
return bm_change_bits_to(device, s, e, 1); |
|
} |
|
|
|
/* returns number of bits changed 1 -> 0 */ |
|
int drbd_bm_clear_bits(struct drbd_device *device, const unsigned long s, const unsigned long e) |
|
{ |
|
return -bm_change_bits_to(device, s, e, 0); |
|
} |
|
|
|
/* sets all bits in full words, |
|
* from first_word up to, but not including, last_word */ |
|
static inline void bm_set_full_words_within_one_page(struct drbd_bitmap *b, |
|
int page_nr, int first_word, int last_word) |
|
{ |
|
int i; |
|
int bits; |
|
int changed = 0; |
|
unsigned long *paddr = kmap_atomic(b->bm_pages[page_nr]); |
|
|
|
/* I think it is more cache line friendly to hweight_long then set to ~0UL, |
|
* than to first bitmap_weight() all words, then bitmap_fill() all words */ |
|
for (i = first_word; i < last_word; i++) { |
|
bits = hweight_long(paddr[i]); |
|
paddr[i] = ~0UL; |
|
changed += BITS_PER_LONG - bits; |
|
} |
|
kunmap_atomic(paddr); |
|
if (changed) { |
|
/* We only need lazy writeout, the information is still in the |
|
* remote bitmap as well, and is reconstructed during the next |
|
* bitmap exchange, if lost locally due to a crash. */ |
|
bm_set_page_lazy_writeout(b->bm_pages[page_nr]); |
|
b->bm_set += changed; |
|
} |
|
} |
|
|
|
/* Same thing as drbd_bm_set_bits, |
|
* but more efficient for a large bit range. |
|
* You must first drbd_bm_lock(). |
|
* Can be called to set the whole bitmap in one go. |
|
* Sets bits from s to e _inclusive_. */ |
|
void _drbd_bm_set_bits(struct drbd_device *device, const unsigned long s, const unsigned long e) |
|
{ |
|
/* First set_bit from the first bit (s) |
|
* up to the next long boundary (sl), |
|
* then assign full words up to the last long boundary (el), |
|
* then set_bit up to and including the last bit (e). |
|
* |
|
* Do not use memset, because we must account for changes, |
|
* so we need to loop over the words with hweight() anyways. |
|
*/ |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long sl = ALIGN(s,BITS_PER_LONG); |
|
unsigned long el = (e+1) & ~((unsigned long)BITS_PER_LONG-1); |
|
int first_page; |
|
int last_page; |
|
int page_nr; |
|
int first_word; |
|
int last_word; |
|
|
|
if (e - s <= 3*BITS_PER_LONG) { |
|
/* don't bother; el and sl may even be wrong. */ |
|
spin_lock_irq(&b->bm_lock); |
|
__bm_change_bits_to(device, s, e, 1); |
|
spin_unlock_irq(&b->bm_lock); |
|
return; |
|
} |
|
|
|
/* difference is large enough that we can trust sl and el */ |
|
|
|
spin_lock_irq(&b->bm_lock); |
|
|
|
/* bits filling the current long */ |
|
if (sl) |
|
__bm_change_bits_to(device, s, sl-1, 1); |
|
|
|
first_page = sl >> (3 + PAGE_SHIFT); |
|
last_page = el >> (3 + PAGE_SHIFT); |
|
|
|
/* MLPP: modulo longs per page */ |
|
/* LWPP: long words per page */ |
|
first_word = MLPP(sl >> LN2_BPL); |
|
last_word = LWPP; |
|
|
|
/* first and full pages, unless first page == last page */ |
|
for (page_nr = first_page; page_nr < last_page; page_nr++) { |
|
bm_set_full_words_within_one_page(device->bitmap, page_nr, first_word, last_word); |
|
spin_unlock_irq(&b->bm_lock); |
|
cond_resched(); |
|
first_word = 0; |
|
spin_lock_irq(&b->bm_lock); |
|
} |
|
/* last page (respectively only page, for first page == last page) */ |
|
last_word = MLPP(el >> LN2_BPL); |
|
|
|
/* consider bitmap->bm_bits = 32768, bitmap->bm_number_of_pages = 1. (or multiples). |
|
* ==> e = 32767, el = 32768, last_page = 2, |
|
* and now last_word = 0. |
|
* We do not want to touch last_page in this case, |
|
* as we did not allocate it, it is not present in bitmap->bm_pages. |
|
*/ |
|
if (last_word) |
|
bm_set_full_words_within_one_page(device->bitmap, last_page, first_word, last_word); |
|
|
|
/* possibly trailing bits. |
|
* example: (e & 63) == 63, el will be e+1. |
|
* if that even was the very last bit, |
|
* it would trigger an assert in __bm_change_bits_to() |
|
*/ |
|
if (el <= e) |
|
__bm_change_bits_to(device, el, e, 1); |
|
spin_unlock_irq(&b->bm_lock); |
|
} |
|
|
|
/* returns bit state |
|
* wants bitnr, NOT sector. |
|
* inherently racy... area needs to be locked by means of {al,rs}_lru |
|
* 1 ... bit set |
|
* 0 ... bit not set |
|
* -1 ... first out of bounds access, stop testing for bits! |
|
*/ |
|
int drbd_bm_test_bit(struct drbd_device *device, const unsigned long bitnr) |
|
{ |
|
unsigned long flags; |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long *p_addr; |
|
int i; |
|
|
|
if (!expect(b)) |
|
return 0; |
|
if (!expect(b->bm_pages)) |
|
return 0; |
|
|
|
spin_lock_irqsave(&b->bm_lock, flags); |
|
if (BM_DONT_TEST & b->bm_flags) |
|
bm_print_lock_info(device); |
|
if (bitnr < b->bm_bits) { |
|
p_addr = bm_map_pidx(b, bm_bit_to_page_idx(b, bitnr)); |
|
i = test_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr) ? 1 : 0; |
|
bm_unmap(p_addr); |
|
} else if (bitnr == b->bm_bits) { |
|
i = -1; |
|
} else { /* (bitnr > b->bm_bits) */ |
|
drbd_err(device, "bitnr=%lu > bm_bits=%lu\n", bitnr, b->bm_bits); |
|
i = 0; |
|
} |
|
|
|
spin_unlock_irqrestore(&b->bm_lock, flags); |
|
return i; |
|
} |
|
|
|
/* returns number of bits set in the range [s, e] */ |
|
int drbd_bm_count_bits(struct drbd_device *device, const unsigned long s, const unsigned long e) |
|
{ |
|
unsigned long flags; |
|
struct drbd_bitmap *b = device->bitmap; |
|
unsigned long *p_addr = NULL; |
|
unsigned long bitnr; |
|
unsigned int page_nr = -1U; |
|
int c = 0; |
|
|
|
/* If this is called without a bitmap, that is a bug. But just to be |
|
* robust in case we screwed up elsewhere, in that case pretend there |
|
* was one dirty bit in the requested area, so we won't try to do a |
|
* local read there (no bitmap probably implies no disk) */ |
|
if (!expect(b)) |
|
return 1; |
|
if (!expect(b->bm_pages)) |
|
return 1; |
|
|
|
spin_lock_irqsave(&b->bm_lock, flags); |
|
if (BM_DONT_TEST & b->bm_flags) |
|
bm_print_lock_info(device); |
|
for (bitnr = s; bitnr <= e; bitnr++) { |
|
unsigned int idx = bm_bit_to_page_idx(b, bitnr); |
|
if (page_nr != idx) { |
|
page_nr = idx; |
|
if (p_addr) |
|
bm_unmap(p_addr); |
|
p_addr = bm_map_pidx(b, idx); |
|
} |
|
if (expect(bitnr < b->bm_bits)) |
|
c += (0 != test_bit_le(bitnr - (page_nr << (PAGE_SHIFT+3)), p_addr)); |
|
else |
|
drbd_err(device, "bitnr=%lu bm_bits=%lu\n", bitnr, b->bm_bits); |
|
} |
|
if (p_addr) |
|
bm_unmap(p_addr); |
|
spin_unlock_irqrestore(&b->bm_lock, flags); |
|
return c; |
|
} |
|
|
|
|
|
/* inherently racy... |
|
* return value may be already out-of-date when this function returns. |
|
* but the general usage is that this is only use during a cstate when bits are |
|
* only cleared, not set, and typically only care for the case when the return |
|
* value is zero, or we already "locked" this "bitmap extent" by other means. |
|
* |
|
* enr is bm-extent number, since we chose to name one sector (512 bytes) |
|
* worth of the bitmap a "bitmap extent". |
|
* |
|
* TODO |
|
* I think since we use it like a reference count, we should use the real |
|
* reference count of some bitmap extent element from some lru instead... |
|
* |
|
*/ |
|
int drbd_bm_e_weight(struct drbd_device *device, unsigned long enr) |
|
{ |
|
struct drbd_bitmap *b = device->bitmap; |
|
int count, s, e; |
|
unsigned long flags; |
|
unsigned long *p_addr, *bm; |
|
|
|
if (!expect(b)) |
|
return 0; |
|
if (!expect(b->bm_pages)) |
|
return 0; |
|
|
|
spin_lock_irqsave(&b->bm_lock, flags); |
|
if (BM_DONT_TEST & b->bm_flags) |
|
bm_print_lock_info(device); |
|
|
|
s = S2W(enr); |
|
e = min((size_t)S2W(enr+1), b->bm_words); |
|
count = 0; |
|
if (s < b->bm_words) { |
|
int n = e-s; |
|
p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, s)); |
|
bm = p_addr + MLPP(s); |
|
count += bitmap_weight(bm, n * BITS_PER_LONG); |
|
bm_unmap(p_addr); |
|
} else { |
|
drbd_err(device, "start offset (%d) too large in drbd_bm_e_weight\n", s); |
|
} |
|
spin_unlock_irqrestore(&b->bm_lock, flags); |
|
return count; |
|
}
|
|
|