bitmap.c 42.4 KB
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/*
 * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
 *
 * bitmap_create  - sets up the bitmap structure
 * bitmap_destroy - destroys the bitmap structure
 *
 * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
 * - added disk storage for bitmap
 * - changes to allow various bitmap chunk sizes
 * - added bitmap daemon (to asynchronously clear bitmap bits from disk)
 */

/*
 * Still to do:
 *
 * flush after percent set rather than just time based. (maybe both).
 * wait if count gets too high, wake when it drops to half.
 * allow bitmap to be mirrored with superblock (before or after...)
 * allow hot-add to re-instate a current device.
 * allow hot-add of bitmap after quiessing device
 */

#include <linux/module.h>
#include <linux/version.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/config.h>
#include <linux/timer.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/buffer_head.h>
#include <linux/raid/md.h>
#include <linux/raid/bitmap.h>

/* debug macros */

#define DEBUG 0

#if DEBUG
/* these are for debugging purposes only! */

/* define one and only one of these */
#define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
#define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
#define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
#define INJECT_FAULTS_4 0 /* undef */
#define INJECT_FAULTS_5 0 /* undef */
#define INJECT_FAULTS_6 0

/* if these are defined, the driver will fail! debug only */
#define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
#define INJECT_FATAL_FAULT_2 0 /* undef */
#define INJECT_FATAL_FAULT_3 0 /* undef */
#endif

//#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
#define DPRINTK(x...) do { } while(0)

#ifndef PRINTK
#  if DEBUG > 0
#    define PRINTK(x...) printk(KERN_DEBUG x)
#  else
#    define PRINTK(x...)
#  endif
#endif

static inline char * bmname(struct bitmap *bitmap)
{
	return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
}


/*
 * test if the bitmap is active
 */
int bitmap_active(struct bitmap *bitmap)
{
	unsigned long flags;
	int res = 0;

	if (!bitmap)
		return res;
	spin_lock_irqsave(&bitmap->lock, flags);
	res = bitmap->flags & BITMAP_ACTIVE;
	spin_unlock_irqrestore(&bitmap->lock, flags);
	return res;
}

#define WRITE_POOL_SIZE 256
/* mempool for queueing pending writes on the bitmap file */
static void *write_pool_alloc(unsigned int gfp_flags, void *data)
{
	return kmalloc(sizeof(struct page_list), gfp_flags);
}

static void write_pool_free(void *ptr, void *data)
{
	kfree(ptr);
}

/*
 * just a placeholder - calls kmalloc for bitmap pages
 */
static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
{
	unsigned char *page;

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#ifdef INJECT_FAULTS_1
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	page = NULL;
#else
	page = kmalloc(PAGE_SIZE, GFP_NOIO);
#endif
	if (!page)
		printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
	else
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		PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
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			bmname(bitmap), page);
	return page;
}

/*
 * for now just a placeholder -- just calls kfree for bitmap pages
 */
static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
{
	PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
	kfree(page);
}

/*
 * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 *
 * 1) check to see if this page is allocated, if it's not then try to alloc
 * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 *    page pointer directly as a counter
 *
 * if we find our page, we increment the page's refcount so that it stays
 * allocated while we're using it
 */
static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
{
	unsigned char *mappage;

	if (page >= bitmap->pages) {
		printk(KERN_ALERT
			"%s: invalid bitmap page request: %lu (> %lu)\n",
			bmname(bitmap), page, bitmap->pages-1);
		return -EINVAL;
	}


	if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
		return 0;

	if (bitmap->bp[page].map) /* page is already allocated, just return */
		return 0;

	if (!create)
		return -ENOENT;

	spin_unlock_irq(&bitmap->lock);

	/* this page has not been allocated yet */

	if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
		PRINTK("%s: bitmap map page allocation failed, hijacking\n",
			bmname(bitmap));
		/* failed - set the hijacked flag so that we can use the
		 * pointer as a counter */
		spin_lock_irq(&bitmap->lock);
		if (!bitmap->bp[page].map)
			bitmap->bp[page].hijacked = 1;
		goto out;
	}

	/* got a page */

	spin_lock_irq(&bitmap->lock);

	/* recheck the page */

	if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
		/* somebody beat us to getting the page */
		bitmap_free_page(bitmap, mappage);
		return 0;
	}

	/* no page was in place and we have one, so install it */

	memset(mappage, 0, PAGE_SIZE);
	bitmap->bp[page].map = mappage;
	bitmap->missing_pages--;
out:
	return 0;
}


/* if page is completely empty, put it back on the free list, or dealloc it */
/* if page was hijacked, unmark the flag so it might get alloced next time */
/* Note: lock should be held when calling this */
static inline void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
{
	char *ptr;

	if (bitmap->bp[page].count) /* page is still busy */
		return;

	/* page is no longer in use, it can be released */

	if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
		bitmap->bp[page].hijacked = 0;
		bitmap->bp[page].map = NULL;
		return;
	}

	/* normal case, free the page */

#if 0
/* actually ... let's not.  We will probably need the page again exactly when
 * memory is tight and we are flusing to disk
 */
	return;
#else
	ptr = bitmap->bp[page].map;
	bitmap->bp[page].map = NULL;
	bitmap->missing_pages++;
	bitmap_free_page(bitmap, ptr);
	return;
#endif
}


/*
 * bitmap file handling - read and write the bitmap file and its superblock
 */

/* copy the pathname of a file to a buffer */
char *file_path(struct file *file, char *buf, int count)
{
	struct dentry *d;
	struct vfsmount *v;

	if (!buf)
		return NULL;

	d = file->f_dentry;
	v = file->f_vfsmnt;

	buf = d_path(d, v, buf, count);

	return IS_ERR(buf) ? NULL : buf;
}

/*
 * basic page I/O operations
 */

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/* IO operations when bitmap is stored near all superblocks */
static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
{
	/* choose a good rdev and read the page from there */

	mdk_rdev_t *rdev;
	struct list_head *tmp;
	struct page *page = alloc_page(GFP_KERNEL);
	sector_t target;

	if (!page)
		return ERR_PTR(-ENOMEM);
	do {
		ITERATE_RDEV(mddev, rdev, tmp)
			if (rdev->in_sync && !rdev->faulty)
				goto found;
		return ERR_PTR(-EIO);

	found:
		target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);

	} while (!sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ));

	page->index = index;
	return page;
}

static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
{
	mdk_rdev_t *rdev;
	struct list_head *tmp;

	ITERATE_RDEV(mddev, rdev, tmp)
		if (rdev->in_sync && !rdev->faulty)
			md_super_write(mddev, rdev,
				       (rdev->sb_offset<<1) + offset
				       + page->index * (PAGE_SIZE/512),
				       PAGE_SIZE,
				       page);

	if (wait)
		wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
	return 0;
}

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/*
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 * write out a page to a file
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 */
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static int write_page(struct bitmap *bitmap, struct page *page, int wait)
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{
	int ret = -ENOMEM;

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	if (bitmap->file == NULL)
		return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);

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	if (wait)
		lock_page(page);
	else {
		if (TestSetPageLocked(page))
			return -EAGAIN; /* already locked */
		if (PageWriteback(page)) {
			unlock_page(page);
			return -EAGAIN;
		}
	}
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	ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
	if (!ret)
		ret = page->mapping->a_ops->commit_write(NULL, page, 0,
			PAGE_SIZE);
	if (ret) {
		unlock_page(page);
		return ret;
	}

	set_page_dirty(page); /* force it to be written out */
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	if (!wait) {
		/* add to list to be waited for by daemon */
		struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
		item->page = page;
		page_cache_get(page);
		spin_lock(&bitmap->write_lock);
		list_add(&item->list, &bitmap->complete_pages);
		spin_unlock(&bitmap->write_lock);
		md_wakeup_thread(bitmap->writeback_daemon);
	}
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	return write_one_page(page, wait);
}

/* read a page from a file, pinning it into cache, and return bytes_read */
static struct page *read_page(struct file *file, unsigned long index,
					unsigned long *bytes_read)
{
	struct inode *inode = file->f_mapping->host;
	struct page *page = NULL;
	loff_t isize = i_size_read(inode);
	unsigned long end_index = isize >> PAGE_CACHE_SHIFT;

	PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_CACHE_SIZE,
			(unsigned long long)index << PAGE_CACHE_SHIFT);

	page = read_cache_page(inode->i_mapping, index,
			(filler_t *)inode->i_mapping->a_ops->readpage, file);
	if (IS_ERR(page))
		goto out;
	wait_on_page_locked(page);
	if (!PageUptodate(page) || PageError(page)) {
		page_cache_release(page);
		page = ERR_PTR(-EIO);
		goto out;
	}

	if (index > end_index) /* we have read beyond EOF */
		*bytes_read = 0;
	else if (index == end_index) /* possible short read */
		*bytes_read = isize & ~PAGE_CACHE_MASK;
	else
		*bytes_read = PAGE_CACHE_SIZE; /* got a full page */
out:
	if (IS_ERR(page))
		printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
			(int)PAGE_CACHE_SIZE,
			(unsigned long long)index << PAGE_CACHE_SHIFT,
			PTR_ERR(page));
	return page;
}

/*
 * bitmap file superblock operations
 */

/* update the event counter and sync the superblock to disk */
int bitmap_update_sb(struct bitmap *bitmap)
{
	bitmap_super_t *sb;
	unsigned long flags;

	if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
		return 0;
	spin_lock_irqsave(&bitmap->lock, flags);
	if (!bitmap->sb_page) { /* no superblock */
		spin_unlock_irqrestore(&bitmap->lock, flags);
		return 0;
	}
	spin_unlock_irqrestore(&bitmap->lock, flags);
	sb = (bitmap_super_t *)kmap(bitmap->sb_page);
	sb->events = cpu_to_le64(bitmap->mddev->events);
	if (!bitmap->mddev->degraded)
		sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
	kunmap(bitmap->sb_page);
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	return write_page(bitmap, bitmap->sb_page, 1);
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}

/* print out the bitmap file superblock */
void bitmap_print_sb(struct bitmap *bitmap)
{
	bitmap_super_t *sb;

	if (!bitmap || !bitmap->sb_page)
		return;
	sb = (bitmap_super_t *)kmap(bitmap->sb_page);
	printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
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	printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
	printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
	printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
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					*(__u32 *)(sb->uuid+0),
					*(__u32 *)(sb->uuid+4),
					*(__u32 *)(sb->uuid+8),
					*(__u32 *)(sb->uuid+12));
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	printk(KERN_DEBUG "        events: %llu\n",
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			(unsigned long long) le64_to_cpu(sb->events));
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	printk(KERN_DEBUG "events cleared: %llu\n",
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			(unsigned long long) le64_to_cpu(sb->events_cleared));
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	printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
	printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
	printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
	printk(KERN_DEBUG "     sync size: %llu KB\n",
			(unsigned long long)le64_to_cpu(sb->sync_size)/2);
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	printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
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	kunmap(bitmap->sb_page);
}

/* read the superblock from the bitmap file and initialize some bitmap fields */
static int bitmap_read_sb(struct bitmap *bitmap)
{
	char *reason = NULL;
	bitmap_super_t *sb;
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	unsigned long chunksize, daemon_sleep, write_behind;
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	unsigned long bytes_read;
	unsigned long long events;
	int err = -EINVAL;

	/* page 0 is the superblock, read it... */
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	if (bitmap->file)
		bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
	else {
		bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
		bytes_read = PAGE_SIZE;
	}
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	if (IS_ERR(bitmap->sb_page)) {
		err = PTR_ERR(bitmap->sb_page);
		bitmap->sb_page = NULL;
		return err;
	}

	sb = (bitmap_super_t *)kmap(bitmap->sb_page);

	if (bytes_read < sizeof(*sb)) { /* short read */
		printk(KERN_INFO "%s: bitmap file superblock truncated\n",
			bmname(bitmap));
		err = -ENOSPC;
		goto out;
	}

	chunksize = le32_to_cpu(sb->chunksize);
	daemon_sleep = le32_to_cpu(sb->daemon_sleep);
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	write_behind = le32_to_cpu(sb->write_behind);
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	/* verify that the bitmap-specific fields are valid */
	if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
		reason = "bad magic";
	else if (sb->version != cpu_to_le32(BITMAP_MAJOR))
		reason = "unrecognized superblock version";
	else if (chunksize < 512 || chunksize > (1024 * 1024 * 4))
		reason = "bitmap chunksize out of range (512B - 4MB)";
	else if ((1 << ffz(~chunksize)) != chunksize)
		reason = "bitmap chunksize not a power of 2";
	else if (daemon_sleep < 1 || daemon_sleep > 15)
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		reason = "daemon sleep period out of range (1-15s)";
	else if (write_behind > COUNTER_MAX)
		reason = "write-behind limit out of range (0 - 16383)";
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	if (reason) {
		printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
			bmname(bitmap), reason);
		goto out;
	}

	/* keep the array size field of the bitmap superblock up to date */
	sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);

	if (!bitmap->mddev->persistent)
		goto success;

	/*
	 * if we have a persistent array superblock, compare the
	 * bitmap's UUID and event counter to the mddev's
	 */
	if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
		printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
			bmname(bitmap));
		goto out;
	}
	events = le64_to_cpu(sb->events);
	if (events < bitmap->mddev->events) {
		printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
			"-- forcing full recovery\n", bmname(bitmap), events,
			(unsigned long long) bitmap->mddev->events);
		sb->state |= BITMAP_STALE;
	}
success:
	/* assign fields using values from superblock */
	bitmap->chunksize = chunksize;
	bitmap->daemon_sleep = daemon_sleep;
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	bitmap->daemon_lastrun = jiffies;
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	bitmap->max_write_behind = write_behind;
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	bitmap->flags |= sb->state;
	bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
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	if (sb->state & BITMAP_STALE)
		bitmap->events_cleared = bitmap->mddev->events;
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	err = 0;
out:
	kunmap(bitmap->sb_page);
	if (err)
		bitmap_print_sb(bitmap);
	return err;
}

enum bitmap_mask_op {
	MASK_SET,
	MASK_UNSET
};

/* record the state of the bitmap in the superblock */
static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
				enum bitmap_mask_op op)
{
	bitmap_super_t *sb;
	unsigned long flags;

	spin_lock_irqsave(&bitmap->lock, flags);
	if (!bitmap || !bitmap->sb_page) { /* can't set the state */
		spin_unlock_irqrestore(&bitmap->lock, flags);
		return;
	}
	page_cache_get(bitmap->sb_page);
	spin_unlock_irqrestore(&bitmap->lock, flags);
	sb = (bitmap_super_t *)kmap(bitmap->sb_page);
	switch (op) {
		case MASK_SET: sb->state |= bits;
				break;
		case MASK_UNSET: sb->state &= ~bits;
				break;
		default: BUG();
	}
	kunmap(bitmap->sb_page);
	page_cache_release(bitmap->sb_page);
}

/*
 * general bitmap file operations
 */

/* calculate the index of the page that contains this bit */
static inline unsigned long file_page_index(unsigned long chunk)
{
	return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
}

/* calculate the (bit) offset of this bit within a page */
static inline unsigned long file_page_offset(unsigned long chunk)
{
	return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
}

/*
 * return a pointer to the page in the filemap that contains the given bit
 *
 * this lookup is complicated by the fact that the bitmap sb might be exactly
 * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 * 0 or page 1
 */
static inline struct page *filemap_get_page(struct bitmap *bitmap,
					unsigned long chunk)
{
	return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
}


static void bitmap_file_unmap(struct bitmap *bitmap)
{
	struct page **map, *sb_page;
	unsigned long *attr;
	int pages;
	unsigned long flags;

	spin_lock_irqsave(&bitmap->lock, flags);
	map = bitmap->filemap;
	bitmap->filemap = NULL;
	attr = bitmap->filemap_attr;
	bitmap->filemap_attr = NULL;
	pages = bitmap->file_pages;
	bitmap->file_pages = 0;
	sb_page = bitmap->sb_page;
	bitmap->sb_page = NULL;
	spin_unlock_irqrestore(&bitmap->lock, flags);

	while (pages--)
		if (map[pages]->index != 0) /* 0 is sb_page, release it below */
			page_cache_release(map[pages]);
	kfree(map);
	kfree(attr);

	if (sb_page)
		page_cache_release(sb_page);
}

static void bitmap_stop_daemons(struct bitmap *bitmap);

/* dequeue the next item in a page list -- don't call from irq context */
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static struct page_list *dequeue_page(struct bitmap *bitmap)
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{
	struct page_list *item = NULL;
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	struct list_head *head = &bitmap->complete_pages;
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	spin_lock(&bitmap->write_lock);
	if (list_empty(head))
		goto out;
	item = list_entry(head->prev, struct page_list, list);
	list_del(head->prev);
out:
	spin_unlock(&bitmap->write_lock);
	return item;
}

static void drain_write_queues(struct bitmap *bitmap)
{
	struct page_list *item;

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	while ((item = dequeue_page(bitmap))) {
		/* don't bother to wait */
		page_cache_release(item->page);
		mempool_free(item, bitmap->write_pool);
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	}

	wake_up(&bitmap->write_wait);
}

static void bitmap_file_put(struct bitmap *bitmap)
{
	struct file *file;
	struct inode *inode;
	unsigned long flags;

	spin_lock_irqsave(&bitmap->lock, flags);
	file = bitmap->file;
	bitmap->file = NULL;
	spin_unlock_irqrestore(&bitmap->lock, flags);

	bitmap_stop_daemons(bitmap);

	drain_write_queues(bitmap);

	bitmap_file_unmap(bitmap);

	if (file) {
		inode = file->f_mapping->host;
		spin_lock(&inode->i_lock);
		atomic_set(&inode->i_writecount, 1); /* allow writes again */
		spin_unlock(&inode->i_lock);
		fput(file);
	}
}


/*
 * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 * then it is no longer reliable, so we stop using it and we mark the file
 * as failed in the superblock
 */
static void bitmap_file_kick(struct bitmap *bitmap)
{
	char *path, *ptr = NULL;

	bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
	bitmap_update_sb(bitmap);

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	if (bitmap->file) {
		path = kmalloc(PAGE_SIZE, GFP_KERNEL);
		if (path)
			ptr = file_path(bitmap->file, path, PAGE_SIZE);
702

703 704
		printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
		       bmname(bitmap), ptr ? ptr : "");
705

706 707
		kfree(path);
	}
708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750

	bitmap_file_put(bitmap);

	return;
}

enum bitmap_page_attr {
	BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
	BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
	BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
};

static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
				enum bitmap_page_attr attr)
{
	bitmap->filemap_attr[page->index] |= attr;
}

static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
				enum bitmap_page_attr attr)
{
	bitmap->filemap_attr[page->index] &= ~attr;
}

static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
{
	return bitmap->filemap_attr[page->index];
}

/*
 * bitmap_file_set_bit -- called before performing a write to the md device
 * to set (and eventually sync) a particular bit in the bitmap file
 *
 * we set the bit immediately, then we record the page number so that
 * when an unplug occurs, we can flush the dirty pages out to disk
 */
static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
{
	unsigned long bit;
	struct page *page;
	void *kaddr;
	unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);

751
	if (!bitmap->filemap) {
752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781
		return;
	}

	page = filemap_get_page(bitmap, chunk);
	bit = file_page_offset(chunk);


	/* make sure the page stays cached until it gets written out */
	if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
		page_cache_get(page);

 	/* set the bit */
	kaddr = kmap_atomic(page, KM_USER0);
	set_bit(bit, kaddr);
	kunmap_atomic(kaddr, KM_USER0);
	PRINTK("set file bit %lu page %lu\n", bit, page->index);

	/* record page number so it gets flushed to disk when unplug occurs */
	set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);

}

/* this gets called when the md device is ready to unplug its underlying
 * (slave) device queues -- before we let any writes go down, we need to
 * sync the dirty pages of the bitmap file to disk */
int bitmap_unplug(struct bitmap *bitmap)
{
	unsigned long i, attr, flags;
	struct page *page;
	int wait = 0;
782
	int err;
783 784 785 786 787 788 789 790

	if (!bitmap)
		return 0;

	/* look at each page to see if there are any set bits that need to be
	 * flushed out to disk */
	for (i = 0; i < bitmap->file_pages; i++) {
		spin_lock_irqsave(&bitmap->lock, flags);
791
		if (!bitmap->filemap) {
792 793 794 795 796 797 798 799 800 801 802
			spin_unlock_irqrestore(&bitmap->lock, flags);
			return 0;
		}
		page = bitmap->filemap[i];
		attr = get_page_attr(bitmap, page);
		clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
		clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
		if ((attr & BITMAP_PAGE_DIRTY))
			wait = 1;
		spin_unlock_irqrestore(&bitmap->lock, flags);

803 804 805 806 807 808 809 810 811
		if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE)) {
			err = write_page(bitmap, page, 0);
			if (err == -EAGAIN) {
				if (attr & BITMAP_PAGE_DIRTY)
					err = write_page(bitmap, page, 1);
				else
					err = 0;
			}
			if (err)
812
				return 1;
813
		}
814 815
	}
	if (wait) { /* if any writes were performed, we need to wait on them */
816 817 818 819 820 821 822 823 824
		if (bitmap->file) {
			spin_lock_irq(&bitmap->write_lock);
			wait_event_lock_irq(bitmap->write_wait,
					    list_empty(&bitmap->complete_pages), bitmap->write_lock,
					    wake_up_process(bitmap->writeback_daemon->tsk));
			spin_unlock_irq(&bitmap->write_lock);
		} else
			wait_event(bitmap->mddev->sb_wait,
				   atomic_read(&bitmap->mddev->pending_writes)==0);
825 826 827 828
	}
	return 0;
}

829
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
830 831 832 833 834 835 836
/* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 * memory mapping of the bitmap file
 * Special cases:
 *   if there's no bitmap file, or if the bitmap file had been
 *   previously kicked from the array, we mark all the bits as
 *   1's in order to cause a full resync.
837 838 839
 *
 * We ignore all bits for sectors that end earlier than 'start'.
 * This is used when reading an out-of-date bitmap...
840
 */
841
static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
842 843 844 845 846 847 848 849 850 851 852 853
{
	unsigned long i, chunks, index, oldindex, bit;
	struct page *page = NULL, *oldpage = NULL;
	unsigned long num_pages, bit_cnt = 0;
	struct file *file;
	unsigned long bytes, offset, dummy;
	int outofdate;
	int ret = -ENOSPC;

	chunks = bitmap->chunks;
	file = bitmap->file;

854
	BUG_ON(!file && !bitmap->offset);
855

856
#ifdef INJECT_FAULTS_3
857 858 859 860 861 862 863 864 865
	outofdate = 1;
#else
	outofdate = bitmap->flags & BITMAP_STALE;
#endif
	if (outofdate)
		printk(KERN_INFO "%s: bitmap file is out of date, doing full "
			"recovery\n", bmname(bitmap));

	bytes = (chunks + 7) / 8;
866

867
	num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
868

869
	if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
870 871 872 873 874 875
		printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
			bmname(bitmap),
			(unsigned long) i_size_read(file->f_mapping->host),
			bytes + sizeof(bitmap_super_t));
		goto out;
	}
876 877 878

	ret = -ENOMEM;

879
	bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
880
	if (!bitmap->filemap)
881 882 883
		goto out;

	bitmap->filemap_attr = kmalloc(sizeof(long) * num_pages, GFP_KERNEL);
884
	if (!bitmap->filemap_attr)
885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
		goto out;

	memset(bitmap->filemap_attr, 0, sizeof(long) * num_pages);

	oldindex = ~0L;

	for (i = 0; i < chunks; i++) {
		index = file_page_index(i);
		bit = file_page_offset(i);
		if (index != oldindex) { /* this is a new page, read it in */
			/* unmap the old page, we're done with it */
			if (oldpage != NULL)
				kunmap(oldpage);
			if (index == 0) {
				/*
				 * if we're here then the superblock page
				 * contains some bits (PAGE_SIZE != sizeof sb)
				 * we've already read it in, so just use it
				 */
				page = bitmap->sb_page;
				offset = sizeof(bitmap_super_t);
906
			} else if (file) {
907
				page = read_page(file, index, &dummy);
908 909 910
				offset = 0;
			} else {
				page = read_sb_page(bitmap->mddev, bitmap->offset, index);
911 912
				offset = 0;
			}
913 914 915 916 917
			if (IS_ERR(page)) { /* read error */
				ret = PTR_ERR(page);
				goto out;
			}

918 919 920 921 922 923 924 925 926 927
			oldindex = index;
			oldpage = page;
			kmap(page);

			if (outofdate) {
				/*
				 * if bitmap is out of date, dirty the
			 	 * whole page and write it out
				 */
				memset(page_address(page) + offset, 0xff,
928
				       PAGE_SIZE - offset);
929
				ret = write_page(bitmap, page, 1);
930 931 932 933 934 935 936 937 938 939 940 941
				if (ret) {
					kunmap(page);
					/* release, page not in filemap yet */
					page_cache_release(page);
					goto out;
				}
			}

			bitmap->filemap[bitmap->file_pages++] = page;
		}
		if (test_bit(bit, page_address(page))) {
			/* if the disk bit is set, set the memory bit */
942 943 944
			bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
					       ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
				);
945
			bit_cnt++;
946
			set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969
		}
	}

 	/* everything went OK */
	ret = 0;
	bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);

	if (page) /* unmap the last page */
		kunmap(page);

	if (bit_cnt) { /* Kick recovery if any bits were set */
		set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
		md_wakeup_thread(bitmap->mddev->thread);
	}

out:
	printk(KERN_INFO "%s: bitmap initialized from disk: "
		"read %lu/%lu pages, set %lu bits, status: %d\n",
		bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);

	return ret;
}

970 971 972 973 974 975 976 977 978 979 980 981 982
void bitmap_write_all(struct bitmap *bitmap)
{
	/* We don't actually write all bitmap blocks here,
	 * just flag them as needing to be written
	 */

	unsigned long chunks = bitmap->chunks;
	unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
	unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
	while (num_pages--)
		bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
}

983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005

static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
{
	sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
	unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
	bitmap->bp[page].count += inc;
/*
	if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
			      (unsigned long long)offset, inc, bitmap->bp[page].count);
*/
	bitmap_checkfree(bitmap, page);
}
static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
					    sector_t offset, int *blocks,
					    int create);

/*
 * bitmap daemon -- periodically wakes up to clean bits and flush pages
 *			out to disk
 */

int bitmap_daemon_work(struct bitmap *bitmap)
{
1006
	unsigned long j;
1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
	unsigned long flags;
	struct page *page = NULL, *lastpage = NULL;
	int err = 0;
	int blocks;
	int attr;

	if (bitmap == NULL)
		return 0;
	if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
		return 0;
	bitmap->daemon_lastrun = jiffies;

	for (j = 0; j < bitmap->chunks; j++) {
		bitmap_counter_t *bmc;
		spin_lock_irqsave(&bitmap->lock, flags);
1022
		if (!bitmap->filemap) {
1023 1024 1025 1026 1027 1028 1029 1030
			/* error or shutdown */
			spin_unlock_irqrestore(&bitmap->lock, flags);
			break;
		}

		page = filemap_get_page(bitmap, j);

		if (page != lastpage) {
1031 1032 1033 1034 1035 1036 1037 1038
			/* skip this page unless it's marked as needing cleaning */
			if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
				if (attr & BITMAP_PAGE_NEEDWRITE) {
					page_cache_get(page);
					clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
				}
				spin_unlock_irqrestore(&bitmap->lock, flags);
				if (attr & BITMAP_PAGE_NEEDWRITE) {
1039 1040 1041 1042 1043 1044 1045
					switch (write_page(bitmap, page, 0)) {
					case -EAGAIN:
						set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
						break;
					case 0:
						break;
					default:
1046
						bitmap_file_kick(bitmap);
1047
					}
1048 1049 1050 1051 1052
					page_cache_release(page);
				}
				continue;
			}

1053 1054 1055 1056 1057 1058
			/* grab the new page, sync and release the old */
			page_cache_get(page);
			if (lastpage != NULL) {
				if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
					clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
					spin_unlock_irqrestore(&bitmap->lock, flags);
1059
					err = write_page(bitmap, lastpage, 0);
1060 1061 1062 1063
					if (err == -EAGAIN) {
						err = 0;
						set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
					}
1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
				} else {
					set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
					spin_unlock_irqrestore(&bitmap->lock, flags);
				}
				kunmap(lastpage);
				page_cache_release(lastpage);
				if (err)
					bitmap_file_kick(bitmap);
			} else
				spin_unlock_irqrestore(&bitmap->lock, flags);
			lastpage = page;
			kmap(page);
/*
			printk("bitmap clean at page %lu\n", j);
*/
			spin_lock_irqsave(&bitmap->lock, flags);
			clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
		}
		bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
					&blocks, 0);
		if (bmc) {
/*
  if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
*/
			if (*bmc == 2) {
				*bmc=1; /* maybe clear the bit next time */
				set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
			} else if (*bmc == 1) {
				/* we can clear the bit */
				*bmc = 0;
				bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
						  -1);

				/* clear the bit */
1098
				clear_bit(file_page_offset(j), page_address(page));
1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110
			}
		}
		spin_unlock_irqrestore(&bitmap->lock, flags);
	}

	/* now sync the final page */
	if (lastpage != NULL) {
		kunmap(lastpage);
		spin_lock_irqsave(&bitmap->lock, flags);
		if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
			clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
			spin_unlock_irqrestore(&bitmap->lock, flags);
1111
			err = write_page(bitmap, lastpage, 0);
1112 1113 1114 1115
			if (err == -EAGAIN) {
				set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
				err = 0;
			}
1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150
		} else {
			set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
			spin_unlock_irqrestore(&bitmap->lock, flags);
		}

		page_cache_release(lastpage);
	}

	return err;
}

static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
{
	mdk_thread_t *dmn;
	unsigned long flags;

	/* if no one is waiting on us, we'll free the md thread struct
	 * and exit, otherwise we let the waiter clean things up */
	spin_lock_irqsave(&bitmap->lock, flags);
	if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
		*daemon = NULL;
		spin_unlock_irqrestore(&bitmap->lock, flags);
		kfree(dmn);
		complete_and_exit(NULL, 0); /* do_exit not exported */
	}
	spin_unlock_irqrestore(&bitmap->lock, flags);
}

static void bitmap_writeback_daemon(mddev_t *mddev)
{
	struct bitmap *bitmap = mddev->bitmap;
	struct page *page;
	struct page_list *item;
	int err = 0;

1151 1152 1153 1154 1155 1156 1157
	if (signal_pending(current)) {
		printk(KERN_INFO
		       "%s: bitmap writeback daemon got signal, exiting...\n",
		       bmname(bitmap));
		err = -EINTR;
		goto out;
	}
1158

1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175
	PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
	/* wait on bitmap page writebacks */
	while ((item = dequeue_page(bitmap))) {
		page = item->page;
		mempool_free(item, bitmap->write_pool);
		PRINTK("wait on page writeback: %p\n", page);
		wait_on_page_writeback(page);
		PRINTK("finished page writeback: %p\n", page);

		err = PageError(page);
		page_cache_release(page);
		if (err) {
			printk(KERN_WARNING "%s: bitmap file writeback "
			       "failed (page %lu): %d\n",
			       bmname(bitmap), page->index, err);
			bitmap_file_kick(bitmap);
			goto out;
1176 1177
		}
	}
1178 1179
 out:
	wake_up(&bitmap->write_wait);
1180 1181
	if (err) {
		printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
1182
		       bmname(bitmap), err);
1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195
		daemon_exit(bitmap, &bitmap->writeback_daemon);
	}
}

static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
				void (*func)(mddev_t *), char *name)
{
	mdk_thread_t *daemon;
	unsigned long flags;
	char namebuf[32];

	spin_lock_irqsave(&bitmap->lock, flags);
	*ptr = NULL;
1196

1197 1198 1199 1200 1201
	if (!bitmap->file) /* no need for daemon if there's no backing file */
		goto out_unlock;

	spin_unlock_irqrestore(&bitmap->lock, flags);

1202
#ifdef INJECT_FATAL_FAULT_2
1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219
	daemon = NULL;
#else
	sprintf(namebuf, "%%s_%s", name);
	daemon = md_register_thread(func, bitmap->mddev, namebuf);
#endif
	if (!daemon) {
		printk(KERN_ERR "%s: failed to start bitmap daemon\n",
			bmname(bitmap));
		return -ECHILD;
	}

	spin_lock_irqsave(&bitmap->lock, flags);
	*ptr = daemon;

	md_wakeup_thread(daemon); /* start it running */

	PRINTK("%s: %s daemon (pid %d) started...\n",
1220
		bmname(bitmap), name, daemon->tsk->pid);
1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290
out_unlock:
	spin_unlock_irqrestore(&bitmap->lock, flags);
	return 0;
}

static int bitmap_start_daemons(struct bitmap *bitmap)
{
	int err = bitmap_start_daemon(bitmap, &bitmap->writeback_daemon,
					bitmap_writeback_daemon, "bitmap_wb");
	return err;
}

static void bitmap_stop_daemon(struct bitmap *bitmap, mdk_thread_t **ptr)
{
	mdk_thread_t *daemon;
	unsigned long flags;

	spin_lock_irqsave(&bitmap->lock, flags);
	daemon = *ptr;
	*ptr = NULL;
	spin_unlock_irqrestore(&bitmap->lock, flags);
	if (daemon)
		md_unregister_thread(daemon); /* destroy the thread */
}

static void bitmap_stop_daemons(struct bitmap *bitmap)
{
	/* the daemons can't stop themselves... they'll just exit instead... */
	if (bitmap->writeback_daemon &&
	    current->pid != bitmap->writeback_daemon->tsk->pid)
		bitmap_stop_daemon(bitmap, &bitmap->writeback_daemon);
}

static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
					    sector_t offset, int *blocks,
					    int create)
{
	/* If 'create', we might release the lock and reclaim it.
	 * The lock must have been taken with interrupts enabled.
	 * If !create, we don't release the lock.
	 */
	sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
	unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
	unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
	sector_t csize;

	if (bitmap_checkpage(bitmap, page, create) < 0) {
		csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
		*blocks = csize - (offset & (csize- 1));
		return NULL;
	}
	/* now locked ... */

	if (bitmap->bp[page].hijacked) { /* hijacked pointer */
		/* should we use the first or second counter field
		 * of the hijacked pointer? */
		int hi = (pageoff > PAGE_COUNTER_MASK);
		csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
					  PAGE_COUNTER_SHIFT - 1);
		*blocks = csize - (offset & (csize- 1));
		return  &((bitmap_counter_t *)
			  &bitmap->bp[page].map)[hi];
	} else { /* page is allocated */
		csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
		*blocks = csize - (offset & (csize- 1));
		return (bitmap_counter_t *)
			&(bitmap->bp[page].map[pageoff]);
	}
}

1291
int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1292 1293
{
	if (!bitmap) return 0;
1294 1295 1296 1297 1298 1299 1300

	if (behind) {
		atomic_inc(&bitmap->behind_writes);
		PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
		  atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
	}

1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334
	while (sectors) {
		int blocks;
		bitmap_counter_t *bmc;

		spin_lock_irq(&bitmap->lock);
		bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
		if (!bmc) {
			spin_unlock_irq(&bitmap->lock);
			return 0;
		}

		switch(*bmc) {
		case 0:
			bitmap_file_set_bit(bitmap, offset);
			bitmap_count_page(bitmap,offset, 1);
			blk_plug_device(bitmap->mddev->queue);
			/* fall through */
		case 1:
			*bmc = 2;
		}
		if ((*bmc & COUNTER_MAX) == COUNTER_MAX) BUG();
		(*bmc)++;

		spin_unlock_irq(&bitmap->lock);

		offset += blocks;
		if (sectors > blocks)
			sectors -= blocks;
		else sectors = 0;
	}
	return 0;
}

void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1335
		     int success, int behind)
1336 1337
{
	if (!bitmap) return;
1338 1339 1340 1341 1342 1343
	if (behind) {
		atomic_dec(&bitmap->behind_writes);
		PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
		  atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
	}

1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
	while (sectors) {
		int blocks;
		unsigned long flags;
		bitmap_counter_t *bmc;

		spin_lock_irqsave(&bitmap->lock, flags);
		bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
		if (!bmc) {
			spin_unlock_irqrestore(&bitmap->lock, flags);
			return;
		}

		if (!success && ! (*bmc & NEEDED_MASK))
			*bmc |= NEEDED_MASK;

		(*bmc)--;
		if (*bmc <= 2) {
			set_page_attr(bitmap,
				      filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
				      BITMAP_PAGE_CLEAN);
		}
		spin_unlock_irqrestore(&bitmap->lock, flags);
		offset += blocks;
		if (sectors > blocks)
			sectors -= blocks;
		else sectors = 0;
	}
}

1373 1374
int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
			int degraded)
1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390
{
	bitmap_counter_t *bmc;
	int rv;
	if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
		*blocks = 1024;
		return 1; /* always resync if no bitmap */
	}
	spin_lock_irq(&bitmap->lock);
	bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
	rv = 0;
	if (bmc) {
		/* locked */
		if (RESYNC(*bmc))
			rv = 1;
		else if (NEEDED(*bmc)) {
			rv = 1;
1391 1392 1393 1394
			if (!degraded) { /* don't set/clear bits if degraded */
				*bmc |= RESYNC_MASK;
				*bmc &= ~NEEDED_MASK;
			}
1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453
		}
	}
	spin_unlock_irq(&bitmap->lock);
	return rv;
}

void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
{
	bitmap_counter_t *bmc;
	unsigned long flags;
/*
	if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
*/	if (bitmap == NULL) {
		*blocks = 1024;
		return;
	}
	spin_lock_irqsave(&bitmap->lock, flags);
	bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
	if (bmc == NULL)
		goto unlock;
	/* locked */
/*
	if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
*/
	if (RESYNC(*bmc)) {
		*bmc &= ~RESYNC_MASK;

		if (!NEEDED(*bmc) && aborted)
			*bmc |= NEEDED_MASK;
		else {
			if (*bmc <= 2) {
				set_page_attr(bitmap,
					      filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
					      BITMAP_PAGE_CLEAN);
			}
		}
	}
 unlock:
	spin_unlock_irqrestore(&bitmap->lock, flags);
}

void bitmap_close_sync(struct bitmap *bitmap)
{
	/* Sync has finished, and any bitmap chunks that weren't synced
	 * properly have been aborted.  It remains to us to clear the
	 * RESYNC bit wherever it is still on
	 */
	sector_t sector = 0;
	int blocks;
	if (!bitmap) return;
	while (sector < bitmap->mddev->resync_max_sectors) {
		bitmap_end_sync(bitmap, sector, &blocks, 0);
/*
		if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
					 (unsigned long long)sector, blocks);
*/		sector += blocks;
	}
}

1454
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1455 1456
{
	/* For each chunk covered by any of these sectors, set the
1457
	 * counter to 1 and set resync_needed.  They should all
1458 1459
	 * be 0 at this point
	 */
1460 1461 1462 1463 1464 1465

	int secs;
	bitmap_counter_t *bmc;
	spin_lock_irq(&bitmap->lock);
	bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
	if (!bmc) {
1466
		spin_unlock_irq(&bitmap->lock);
1467
		return;
1468
	}
1469 1470
	if (! *bmc) {
		struct page *page;
1471
		*bmc = 1 | (needed?NEEDED_MASK:0);
1472 1473 1474 1475 1476 1477
		bitmap_count_page(bitmap, offset, 1);
		page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
		set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
	}
	spin_unlock_irq(&bitmap->lock);

1478 1479
}

1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502
/*
 * flush out any pending updates
 */
void bitmap_flush(mddev_t *mddev)
{
	struct bitmap *bitmap = mddev->bitmap;
	int sleep;

	if (!bitmap) /* there was no bitmap */
		return;

	/* run the daemon_work three time to ensure everything is flushed
	 * that can be
	 */
	sleep = bitmap->daemon_sleep;
	bitmap->daemon_sleep = 0;
	bitmap_daemon_work(bitmap);
	bitmap_daemon_work(bitmap);
	bitmap_daemon_work(bitmap);
	bitmap->daemon_sleep = sleep;
	bitmap_update_sb(bitmap);
}

1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546
/*
 * free memory that was allocated
 */
void bitmap_destroy(mddev_t *mddev)
{
	unsigned long k, pages;
	struct bitmap_page *bp;
	struct bitmap *bitmap = mddev->bitmap;

	if (!bitmap) /* there was no bitmap */
		return;

	mddev->bitmap = NULL; /* disconnect from the md device */

	/* release the bitmap file and kill the daemon */
	bitmap_file_put(bitmap);

	bp = bitmap->bp;
	pages = bitmap->pages;

	/* free all allocated memory */

	mempool_destroy(bitmap->write_pool);

	if (bp) /* deallocate the page memory */
		for (k = 0; k < pages; k++)
			if (bp[k].map && !bp[k].hijacked)
				kfree(bp[k].map);
	kfree(bp);
	kfree(bitmap);
}

/*
 * initialize the bitmap structure
 * if this returns an error, bitmap_destroy must be called to do clean up
 */
int bitmap_create(mddev_t *mddev)
{
	struct bitmap *bitmap;
	unsigned long blocks = mddev->resync_max_sectors;
	unsigned long chunks;
	unsigned long pages;
	struct file *file = mddev->bitmap_file;
	int err;
1547
	sector_t start;
1548 1549 1550

	BUG_ON(sizeof(bitmap_super_t) != 256);

1551
	if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1552 1553
		return 0;

1554 1555
	BUG_ON(file && mddev->bitmap_offset);

1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574
	bitmap = kmalloc(sizeof(*bitmap), GFP_KERNEL);
	if (!bitmap)
		return -ENOMEM;

	memset(bitmap, 0, sizeof(*bitmap));

	spin_lock_init(&bitmap->lock);
	bitmap->mddev = mddev;
	mddev->bitmap = bitmap;

	spin_lock_init(&bitmap->write_lock);
	INIT_LIST_HEAD(&bitmap->complete_pages);
	init_waitqueue_head(&bitmap->write_wait);
	bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
				write_pool_free, NULL);
	if (!bitmap->write_pool)
		return -ENOMEM;

	bitmap->file = file;
1575 1576
	bitmap->offset = mddev->bitmap_offset;
	if (file) get_file(file);
1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598
	/* read superblock from bitmap file (this sets bitmap->chunksize) */
	err = bitmap_read_sb(bitmap);
	if (err)
		return err;

	bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
					sizeof(bitmap->chunksize));

	/* now that chunksize and chunkshift are set, we can use these macros */
 	chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
			CHUNK_BLOCK_RATIO(bitmap);
 	pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;

	BUG_ON(!pages);

	bitmap->chunks = chunks;
	bitmap->pages = pages;
	bitmap->missing_pages = pages;
	bitmap->counter_bits = COUNTER_BITS;

	bitmap->syncchunk = ~0UL;

1599
#ifdef INJECT_FATAL_FAULT_1
1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611
	bitmap->bp = NULL;
#else
	bitmap->bp = kmalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
#endif
	if (!bitmap->bp)
		return -ENOMEM;
	memset(bitmap->bp, 0, pages * sizeof(*bitmap->bp));

	bitmap->flags |= BITMAP_ACTIVE;

	/* now that we have some pages available, initialize the in-memory
	 * bitmap from the on-disk bitmap */
1612 1613 1614 1615 1616 1617
	start = 0;
	if (mddev->degraded == 0
	    || bitmap->events_cleared == mddev->events)
		/* no need to keep dirty bits to optimise a re-add of a missing device */
		start = mddev->recovery_cp;
	err = bitmap_init_from_disk(bitmap, start);
1618

1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639
	if (err)
		return err;

	printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
		pages, bmname(bitmap));

	/* kick off the bitmap daemons */
	err = bitmap_start_daemons(bitmap);
	if (err)
		return err;
	return bitmap_update_sb(bitmap);
}

/* the bitmap API -- for raid personalities */
EXPORT_SYMBOL(bitmap_startwrite);
EXPORT_SYMBOL(bitmap_endwrite);
EXPORT_SYMBOL(bitmap_start_sync);
EXPORT_SYMBOL(bitmap_end_sync);
EXPORT_SYMBOL(bitmap_unplug);
EXPORT_SYMBOL(bitmap_close_sync);
EXPORT_SYMBOL(bitmap_daemon_work);