bitmap.c 38.7 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
 */

/*
 * 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.
 */

#include <linux/module.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";
}

#define WRITE_POOL_SIZE 256

/*
 * 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 */
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static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
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{
	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);

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	ITERATE_RDEV(mddev, rdev, tmp) {
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		if (! test_bit(In_sync, &rdev->flags)
		    || test_bit(Faulty, &rdev->flags))
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			continue;

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

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		if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
			page->index = index;
			return page;
		}
	}
	return ERR_PTR(-EIO);
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}

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)
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		if (test_bit(In_sync, &rdev->flags)
		    && !test_bit(Faulty, &rdev->flags))
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			md_super_write(mddev, rdev,
				       (rdev->sb_offset<<1) + offset
				       + page->index * (PAGE_SIZE/512),
				       PAGE_SIZE,
				       page);

	if (wait)
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		md_super_wait(mddev);
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	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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	flush_dcache_page(page); /* make sure visible to anyone reading the file */

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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(bitmap->file, page, 0, PAGE_SIZE);
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	if (!ret)
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		ret = page->mapping->a_ops->commit_write(bitmap->file, page, 0,
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			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) {
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		/* add to list to be waited for */
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		struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
		item->page = page;
		spin_lock(&bitmap->write_lock);
		list_add(&item->list, &bitmap->complete_pages);
		spin_unlock(&bitmap->write_lock);
	}
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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);
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	unsigned long end_index = isize >> PAGE_SHIFT;
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	PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
			(unsigned long long)index << PAGE_SHIFT);
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	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)) {
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		put_page(page);
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		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 */
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		*bytes_read = isize & ~PAGE_MASK;
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	else
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		*bytes_read = PAGE_SIZE; /* got a full page */
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out:
	if (IS_ERR(page))
		printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
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			(int)PAGE_SIZE,
			(unsigned long long)index << PAGE_SHIFT,
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			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);
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	sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
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	sb->events = cpu_to_le64(bitmap->mddev->events);
	if (!bitmap->mddev->degraded)
		sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
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	kunmap_atomic(sb, KM_USER0);
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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;
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	sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
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	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_atomic(sb, KM_USER0);
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}

/* 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;
	}

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	sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
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	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";
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	else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
		 le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
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		reason = "unrecognized superblock version";
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	else if (chunksize < PAGE_SIZE)
		reason = "bitmap chunksize too small";
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	else if ((1 << ffz(~chunksize)) != chunksize)
		reason = "bitmap chunksize not a power of 2";
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	else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
		reason = "daemon sleep period out of range";
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	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;
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	if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
		bitmap->flags |= BITMAP_HOSTENDIAN;
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	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:
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	kunmap_atomic(sb, KM_USER0);
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	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);
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	if (!bitmap->sb_page) { /* can't set the state */
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		spin_unlock_irqrestore(&bitmap->lock, flags);
		return;
	}
	spin_unlock_irqrestore(&bitmap->lock, flags);
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	sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
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	switch (op) {
		case MASK_SET: sb->state |= bits;
				break;
		case MASK_UNSET: sb->state &= ~bits;
				break;
		default: BUG();
	}
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	kunmap_atomic(sb, KM_USER0);
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}

/*
 * 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 */
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			put_page(map[pages]);
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	kfree(map);
	kfree(attr);

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	safe_put_page(sb_page);
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}

/* 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 */
		mempool_free(item, bitmap->write_pool);
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	}
}

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

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

	drain_write_queues(bitmap);

	bitmap_file_unmap(bitmap);

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	if (file)
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		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);
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		printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
		       bmname(bitmap), ptr ? ptr : "");
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		kfree(path);
	}
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	bitmap_file_put(bitmap);

	return;
}

enum bitmap_page_attr {
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	BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
	BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
	BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
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};

static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
				enum bitmap_page_attr attr)
{
681
	__set_bit((page->index<<2) + attr, bitmap->filemap_attr);
682 683 684 685 686
}

static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
				enum bitmap_page_attr attr)
{
687
	__clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
688 689
}

690 691
static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
					   enum bitmap_page_attr attr)
692
{
693
	return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709
}

/*
 * 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);

710
	if (!bitmap->filemap) {
711 712 713 714 715 716 717 718
		return;
	}

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

 	/* set the bit */
	kaddr = kmap_atomic(page, KM_USER0);
719 720 721 722
	if (bitmap->flags & BITMAP_HOSTENDIAN)
		set_bit(bit, kaddr);
	else
		ext2_set_bit(bit, kaddr);
723 724 725 726 727 728 729 730
	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);

}

731 732
static void bitmap_writeback(struct bitmap *bitmap);

733 734 735 736 737
/* 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)
{
738 739
	unsigned long i, flags;
	int dirty, need_write;
740 741
	struct page *page;
	int wait = 0;
742
	int err;
743 744 745 746 747 748 749 750

	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);
751
		if (!bitmap->filemap) {
752 753 754 755
			spin_unlock_irqrestore(&bitmap->lock, flags);
			return 0;
		}
		page = bitmap->filemap[i];
756 757
		dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
		need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
758 759
		clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
		clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
760
		if (dirty)
761 762 763
			wait = 1;
		spin_unlock_irqrestore(&bitmap->lock, flags);

764
		if (dirty | need_write) {
765 766
			err = write_page(bitmap, page, 0);
			if (err == -EAGAIN) {
767
				if (dirty)
768 769 770 771 772
					err = write_page(bitmap, page, 1);
				else
					err = 0;
			}
			if (err)
773
				return 1;
774
		}
775 776
	}
	if (wait) { /* if any writes were performed, we need to wait on them */
777 778 779
		if (bitmap->file)
			bitmap_writeback(bitmap);
		else
780
			md_super_wait(bitmap->mddev);
781 782 783 784
	}
	return 0;
}

785
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
786 787 788 789 790 791 792
/* * 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.
793 794 795
 *
 * We ignore all bits for sectors that end earlier than 'start'.
 * This is used when reading an out-of-date bitmap...
796
 */
797
static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
798 799 800 801 802 803 804 805
{
	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;
806
	void *paddr;
807 808 809 810

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

811
	BUG_ON(!file && !bitmap->offset);
812

813
#ifdef INJECT_FAULTS_3
814 815 816 817 818 819 820 821 822
	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;
823

824
	num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
825

826
	if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
827 828 829 830 831 832
		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;
	}
833 834 835

	ret = -ENOMEM;

836
	bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
837
	if (!bitmap->filemap)
838 839
		goto out;

840 841 842 843 844 845
	/* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
	bitmap->filemap_attr = kzalloc(
		(((num_pages*4/8)+sizeof(unsigned long)-1)
		 /sizeof(unsigned long))
		*sizeof(unsigned long),
		GFP_KERNEL);
846
	if (!bitmap->filemap_attr)
847 848 849 850 851
		goto out;

	oldindex = ~0L;

	for (i = 0; i < chunks; i++) {
852
		int b;
853 854 855 856 857 858 859 860 861 862 863 864
		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 (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);
865
			} else if (file) {
866
				page = read_page(file, index, &dummy);
867 868 869
				offset = 0;
			} else {
				page = read_sb_page(bitmap->mddev, bitmap->offset, index);
870 871
				offset = 0;
			}
872 873 874 875 876
			if (IS_ERR(page)) { /* read error */
				ret = PTR_ERR(page);
				goto out;
			}

877 878 879 880 881 882 883 884
			oldindex = index;
			oldpage = page;

			if (outofdate) {
				/*
				 * if bitmap is out of date, dirty the
			 	 * whole page and write it out
				 */
885 886
				paddr = kmap_atomic(page, KM_USER0);
				memset(paddr + offset, 0xff,
887
				       PAGE_SIZE - offset);
888
				kunmap_atomic(paddr, KM_USER0);
889
				ret = write_page(bitmap, page, 1);
890 891
				if (ret) {
					/* release, page not in filemap yet */
892
					put_page(page);
893 894 895 896 897 898
					goto out;
				}
			}

			bitmap->filemap[bitmap->file_pages++] = page;
		}
899
		paddr = kmap_atomic(page, KM_USER0);
900
		if (bitmap->flags & BITMAP_HOSTENDIAN)
901
			b = test_bit(bit, paddr);
902
		else
903 904
			b = ext2_test_bit(bit, paddr);
		kunmap_atomic(paddr, KM_USER0);
905
		if (b) {
906
			/* if the disk bit is set, set the memory bit */
907 908 909
			bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
					       ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
				);
910
			bit_cnt++;
911
			set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931
		}
	}

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

	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;
}

932 933 934 935 936
void bitmap_write_all(struct bitmap *bitmap)
{
	/* We don't actually write all bitmap blocks here,
	 * just flag them as needing to be written
	 */
937
	int i;
938

939 940 941
	for (i=0; i < bitmap->file_pages; i++)
		set_page_attr(bitmap, bitmap->filemap[i],
			      BITMAP_PAGE_NEEDWRITE);
942 943
}

944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966

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)
{
967
	unsigned long j;
968 969 970 971
	unsigned long flags;
	struct page *page = NULL, *lastpage = NULL;
	int err = 0;
	int blocks;
972
	void *paddr;
973 974 975 976 977 978 979 980 981 982

	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);
983
		if (!bitmap->filemap) {
984 985 986 987 988 989 990 991
			/* error or shutdown */
			spin_unlock_irqrestore(&bitmap->lock, flags);
			break;
		}

		page = filemap_get_page(bitmap, j);

		if (page != lastpage) {
992
			/* skip this page unless it's marked as needing cleaning */
993 994 995
			if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
				int need_write = test_page_attr(bitmap, page,
								BITMAP_PAGE_NEEDWRITE);
996
				if (need_write)
997
					clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
998

999
				spin_unlock_irqrestore(&bitmap->lock, flags);
1000
				if (need_write) {
1001 1002 1003 1004 1005 1006 1007
					switch (write_page(bitmap, page, 0)) {
					case -EAGAIN:
						set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
						break;
					case 0:
						break;
					default:
1008
						bitmap_file_kick(bitmap);
1009
					}
1010 1011 1012 1013
				}
				continue;
			}

1014 1015
			/* grab the new page, sync and release the old */
			if (lastpage != NULL) {
1016
				if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1017 1018
					clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
					spin_unlock_irqrestore(&bitmap->lock, flags);
1019
					err = write_page(bitmap, lastpage, 0);
1020 1021 1022 1023
					if (err == -EAGAIN) {
						err = 0;
						set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
					}
1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054
				} else {
					set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
					spin_unlock_irqrestore(&bitmap->lock, flags);
				}
				if (err)
					bitmap_file_kick(bitmap);
			} else
				spin_unlock_irqrestore(&bitmap->lock, flags);
			lastpage = 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 */
1055
				paddr = kmap_atomic(page, KM_USER0);
1056
				if (bitmap->flags & BITMAP_HOSTENDIAN)
1057
					clear_bit(file_page_offset(j), paddr);
1058
				else
1059 1060
					ext2_clear_bit(file_page_offset(j), paddr);
				kunmap_atomic(paddr, KM_USER0);
1061 1062 1063 1064 1065 1066 1067 1068
			}
		}
		spin_unlock_irqrestore(&bitmap->lock, flags);
	}

	/* now sync the final page */
	if (lastpage != NULL) {
		spin_lock_irqsave(&bitmap->lock, flags);
1069
		if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1070 1071
			clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
			spin_unlock_irqrestore(&bitmap->lock, flags);
1072
			err = write_page(bitmap, lastpage, 0);
1073 1074 1075 1076
			if (err == -EAGAIN) {
				set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
				err = 0;
			}
1077 1078 1079 1080 1081 1082 1083 1084 1085
		} else {
			set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
			spin_unlock_irqrestore(&bitmap->lock, flags);
		}
	}

	return err;
}

1086
static void bitmap_writeback(struct bitmap *bitmap)
1087 1088 1089 1090 1091
{
	struct page *page;
	struct page_list *item;
	int err = 0;

1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
	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);
		if (err) {
			printk(KERN_WARNING "%s: bitmap file writeback "
			       "failed (page %lu): %d\n",
			       bmname(bitmap), page->index, err);
			bitmap_file_kick(bitmap);
1107
			break;
1108 1109 1110 1111 1112 1113 1114 1115 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
		}
	}
}

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]);
	}
}

1149
int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1150 1151
{
	if (!bitmap) return 0;
1152 1153 1154 1155 1156 1157 1158

	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);
	}

1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178
	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;
		}
1179
		BUG_ON((*bmc & COUNTER_MAX) == COUNTER_MAX);
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192
		(*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,
1193
		     int success, int behind)
1194 1195
{
	if (!bitmap) return;
1196 1197 1198 1199 1200 1201
	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);
	}

1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230
	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;
	}
}

1231 1232
int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
			int degraded)
1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
{
	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;
1249 1250 1251 1252
			if (!degraded) { /* don't set/clear bits if degraded */
				*bmc |= RESYNC_MASK;
				*bmc &= ~NEEDED_MASK;
			}
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 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311
		}
	}
	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;
	}
}

1312
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1313 1314
{
	/* For each chunk covered by any of these sectors, set the
1315
	 * counter to 1 and set resync_needed.  They should all
1316 1317
	 * be 0 at this point
	 */
1318 1319 1320 1321 1322 1323

	int secs;
	bitmap_counter_t *bmc;
	spin_lock_irq(&bitmap->lock);
	bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
	if (!bmc) {
1324
		spin_unlock_irq(&bitmap->lock);
1325
		return;
1326
	}
1327 1328
	if (! *bmc) {
		struct page *page;
1329
		*bmc = 1 | (needed?NEEDED_MASK:0);
1330 1331 1332 1333 1334 1335
		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);

1336 1337
}

1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360
/*
 * 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);
}

1361 1362 1363
/*
 * free memory that was allocated
 */
1364
static void bitmap_free(struct bitmap *bitmap)
1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388
{
	unsigned long k, pages;
	struct bitmap_page *bp;

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

	/* 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);
}
1389 1390 1391 1392 1393 1394 1395 1396
void bitmap_destroy(mddev_t *mddev)
{
	struct bitmap *bitmap = mddev->bitmap;

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

	mddev->bitmap = NULL; /* disconnect from the md device */
1397 1398
	if (mddev->thread)
		mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1399 1400 1401

	bitmap_free(bitmap);
}
1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414

/*
 * 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;
1415
	sector_t start;
1416 1417 1418

	BUG_ON(sizeof(bitmap_super_t) != 256);

1419
	if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1420 1421
		return 0;

1422 1423
	BUG_ON(file && mddev->bitmap_offset);

1424
	bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1425 1426 1427 1428 1429 1430 1431 1432
	if (!bitmap)
		return -ENOMEM;

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

	spin_lock_init(&bitmap->write_lock);
	INIT_LIST_HEAD(&bitmap->complete_pages);
1433 1434
	bitmap->write_pool = mempool_create_kmalloc_pool(WRITE_POOL_SIZE,
						sizeof(struct page_list));
1435
	err = -ENOMEM;
1436
	if (!bitmap->write_pool)
1437
		goto error;
1438 1439

	bitmap->file = file;
1440 1441
	bitmap->offset = mddev->bitmap_offset;
	if (file) get_file(file);
1442 1443 1444
	/* read superblock from bitmap file (this sets bitmap->chunksize) */
	err = bitmap_read_sb(bitmap);
	if (err)
1445
		goto error;
1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463

	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;

1464
#ifdef INJECT_FATAL_FAULT_1
1465 1466
	bitmap->bp = NULL;
#else
1467
	bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1468
#endif
1469
	err = -ENOMEM;
1470
	if (!bitmap->bp)
1471
		goto error;
1472 1473 1474

	/* now that we have some pages available, initialize the in-memory
	 * bitmap from the on-disk bitmap */
1475 1476 1477 1478 1479 1480
	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);
1481

1482
	if (err)
1483
		goto error;
1484 1485 1486 1487

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

1488 1489
	mddev->bitmap = bitmap;

1490 1491
	mddev->thread->timeout = bitmap->daemon_sleep * HZ;

1492
	return bitmap_update_sb(bitmap);
1493 1494 1495 1496

 error:
	bitmap_free(bitmap);
	return err;
1497 1498 1499 1500 1501 1502 1503 1504 1505 1506
}

/* 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);