bitmap.c 42.6 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/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 */
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static void *write_pool_alloc(gfp_t gfp_flags, void *data)
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{
	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);

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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) {
		/* add to list to be waited for by daemon */
		struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
		item->page = page;
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		get_page(page);
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		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);
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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);
	if (!bitmap || !bitmap->sb_page) { /* can't set the state */
		spin_unlock_irqrestore(&bitmap->lock, flags);
		return;
	}
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	get_page(bitmap->sb_page);
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	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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	put_page(bitmap->sb_page);
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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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}

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static void bitmap_stop_daemon(struct bitmap *bitmap);
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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 */
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		put_page(item->page);
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		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);

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	bitmap_stop_daemon(bitmap);
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	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);

704 705 706 707
	if (bitmap->file) {
		path = kmalloc(PAGE_SIZE, GFP_KERNEL);
		if (path)
			ptr = file_path(bitmap->file, path, PAGE_SIZE);
708

709 710
		printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
		       bmname(bitmap), ptr ? ptr : "");
711

712 713
		kfree(path);
	}
714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756

	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);

757
	if (!bitmap->filemap) {
758 759 760 761 762 763 764 765 766
		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))
767
		get_page(page);
768 769 770

 	/* set the bit */
	kaddr = kmap_atomic(page, KM_USER0);
771 772 773 774
	if (bitmap->flags & BITMAP_HOSTENDIAN)
		set_bit(bit, kaddr);
	else
		ext2_set_bit(bit, kaddr);
775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790
	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;
791
	int err;
792 793 794 795 796 797 798 799

	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);
800
		if (!bitmap->filemap) {
801 802 803 804 805 806 807 808 809 810 811
			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);

812 813 814 815 816 817 818 819 820
		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)
821
				return 1;
822
		}
823 824
	}
	if (wait) { /* if any writes were performed, we need to wait on them */
825 826 827 828 829 830 831
		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
832
			md_super_wait(bitmap->mddev);
833 834 835 836
	}
	return 0;
}

837
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
838 839 840 841 842 843 844
/* * 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.
845 846 847
 *
 * We ignore all bits for sectors that end earlier than 'start'.
 * This is used when reading an out-of-date bitmap...
848
 */
849
static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
850 851 852 853 854 855 856 857
{
	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;
858
	void *paddr;
859 860 861 862

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

863
	BUG_ON(!file && !bitmap->offset);
864

865
#ifdef INJECT_FAULTS_3
866 867 868 869 870 871 872 873 874
	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;
875

876
	num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
877

878
	if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
879 880 881 882 883 884
		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;
	}
885 886 887

	ret = -ENOMEM;

888
	bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
889
	if (!bitmap->filemap)
890 891
		goto out;

892
	bitmap->filemap_attr = kzalloc(sizeof(long) * num_pages, GFP_KERNEL);
893
	if (!bitmap->filemap_attr)
894 895 896 897 898
		goto out;

	oldindex = ~0L;

	for (i = 0; i < chunks; i++) {
899
		int b;
900 901 902 903 904 905 906 907 908 909 910 911
		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);
912
			} else if (file) {
913
				page = read_page(file, index, &dummy);
914 915 916
				offset = 0;
			} else {
				page = read_sb_page(bitmap->mddev, bitmap->offset, index);
917 918
				offset = 0;
			}
919 920 921 922 923
			if (IS_ERR(page)) { /* read error */
				ret = PTR_ERR(page);
				goto out;
			}

924 925 926 927 928 929 930 931
			oldindex = index;
			oldpage = page;

			if (outofdate) {
				/*
				 * if bitmap is out of date, dirty the
			 	 * whole page and write it out
				 */
932 933
				paddr = kmap_atomic(page, KM_USER0);
				memset(paddr + offset, 0xff,
934
				       PAGE_SIZE - offset);
935
				kunmap_atomic(paddr, KM_USER0);
936
				ret = write_page(bitmap, page, 1);
937 938
				if (ret) {
					/* release, page not in filemap yet */
939
					put_page(page);
940 941 942 943 944 945
					goto out;
				}
			}

			bitmap->filemap[bitmap->file_pages++] = page;
		}
946
		paddr = kmap_atomic(page, KM_USER0);
947
		if (bitmap->flags & BITMAP_HOSTENDIAN)
948
			b = test_bit(bit, paddr);
949
		else
950 951
			b = ext2_test_bit(bit, paddr);
		kunmap_atomic(paddr, KM_USER0);
952
		if (b) {
953
			/* if the disk bit is set, set the memory bit */
954 955 956
			bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
					       ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
				);
957
			bit_cnt++;
958
			set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978
		}
	}

 	/* 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;
}

979 980 981 982 983 984 985 986 987 988 989 990 991
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;
}

992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014

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)
{
1015
	unsigned long j;
1016 1017 1018 1019 1020
	unsigned long flags;
	struct page *page = NULL, *lastpage = NULL;
	int err = 0;
	int blocks;
	int attr;
1021
	void *paddr;
1022 1023 1024 1025 1026 1027 1028 1029 1030 1031

	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);
1032
		if (!bitmap->filemap) {
1033 1034 1035 1036 1037 1038 1039 1040
			/* error or shutdown */
			spin_unlock_irqrestore(&bitmap->lock, flags);
			break;
		}

		page = filemap_get_page(bitmap, j);

		if (page != lastpage) {
1041 1042 1043
			/* 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) {
1044
					get_page(page);
1045 1046 1047 1048
					clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
				}
				spin_unlock_irqrestore(&bitmap->lock, flags);
				if (attr & BITMAP_PAGE_NEEDWRITE) {
1049 1050 1051 1052 1053 1054 1055
					switch (write_page(bitmap, page, 0)) {
					case -EAGAIN:
						set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
						break;
					case 0:
						break;
					default:
1056
						bitmap_file_kick(bitmap);
1057
					}
1058
					put_page(page);
1059 1060 1061 1062
				}
				continue;
			}

1063
			/* grab the new page, sync and release the old */
1064
			get_page(page);
1065 1066 1067 1068
			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);
1069
					err = write_page(bitmap, lastpage, 0);
1070 1071 1072 1073
					if (err == -EAGAIN) {
						err = 0;
						set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
					}
1074 1075 1076 1077
				} else {
					set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
					spin_unlock_irqrestore(&bitmap->lock, flags);
				}
1078
				put_page(lastpage);
1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105
				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 */
1106
				paddr = kmap_atomic(page, KM_USER0);
1107
				if (bitmap->flags & BITMAP_HOSTENDIAN)
1108
					clear_bit(file_page_offset(j), paddr);
1109
				else
1110 1111
					ext2_clear_bit(file_page_offset(j), paddr);
				kunmap_atomic(paddr, KM_USER0);
1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122
			}
		}
		spin_unlock_irqrestore(&bitmap->lock, flags);
	}

	/* now sync the final page */
	if (lastpage != NULL) {
		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);
1123
			err = write_page(bitmap, lastpage, 0);
1124 1125 1126 1127
			if (err == -EAGAIN) {
				set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
				err = 0;
			}
1128 1129 1130 1131 1132
		} else {
			set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
			spin_unlock_irqrestore(&bitmap->lock, flags);
		}

1133
		put_page(lastpage);
1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162
	}

	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;

1163 1164 1165 1166 1167 1168 1169
	if (signal_pending(current)) {
		printk(KERN_INFO
		       "%s: bitmap writeback daemon got signal, exiting...\n",
		       bmname(bitmap));
		err = -EINTR;
		goto out;
	}
1170 1171 1172
	if (bitmap == NULL)
		/* about to be stopped. */
		return;
1173

1174 1175 1176 1177 1178 1179 1180 1181 1182 1183
	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);
1184
		put_page(page);
1185 1186 1187 1188 1189 1190
		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;
1191 1192
		}
	}
1193 1194
 out:
	wake_up(&bitmap->write_wait);
1195 1196
	if (err) {
		printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
1197
		       bmname(bitmap), err);
1198 1199 1200 1201
		daemon_exit(bitmap, &bitmap->writeback_daemon);
	}
}

1202
static mdk_thread_t *bitmap_start_daemon(struct bitmap *bitmap,
1203 1204 1205 1206 1207
				void (*func)(mddev_t *), char *name)
{
	mdk_thread_t *daemon;
	char namebuf[32];

1208
#ifdef INJECT_FATAL_FAULT_2
1209 1210 1211 1212 1213 1214 1215 1216
	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));
1217
		return ERR_PTR(-ECHILD);
1218 1219 1220 1221 1222
	}

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

	PRINTK("%s: %s daemon (pid %d) started...\n",
1223
		bmname(bitmap), name, daemon->tsk->pid);
1224

1225
	return daemon;
1226 1227
}

1228
static void bitmap_stop_daemon(struct bitmap *bitmap)
1229
{
1230 1231 1232 1233 1234
	/* the daemon can't stop itself... it'll just exit instead... */
	if (bitmap->writeback_daemon && ! IS_ERR(bitmap->writeback_daemon) &&
	    current->pid != bitmap->writeback_daemon->tsk->pid) {
		mdk_thread_t *daemon;
		unsigned long flags;
1235

1236 1237 1238 1239 1240 1241 1242
		spin_lock_irqsave(&bitmap->lock, flags);
		daemon = bitmap->writeback_daemon;
		bitmap->writeback_daemon = NULL;
		spin_unlock_irqrestore(&bitmap->lock, flags);
		if (daemon && ! IS_ERR(daemon))
			md_unregister_thread(daemon); /* destroy the thread */
	}
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
}

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]);
	}
}

1282
int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1283 1284
{
	if (!bitmap) return 0;
1285 1286 1287 1288 1289 1290 1291

	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);
	}

1292 1293 1294 1295 1296 1297 1298 1299 1300 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
	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,
1326
		     int success, int behind)
1327 1328
{
	if (!bitmap) return;
1329 1330 1331 1332 1333 1334
	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);
	}

1335 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 1361 1362 1363
	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;
	}
}

1364 1365
int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
			int degraded)
1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
{
	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;
1382 1383 1384 1385
			if (!degraded) { /* don't set/clear bits if degraded */
				*bmc |= RESYNC_MASK;
				*bmc &= ~NEEDED_MASK;
			}
1386 1387 1388 1389 1390 1391 1392 1393 1394 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
		}
	}
	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;
	}
}

1445
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1446 1447
{
	/* For each chunk covered by any of these sectors, set the
1448
	 * counter to 1 and set resync_needed.  They should all
1449 1450
	 * be 0 at this point
	 */
1451 1452 1453 1454 1455 1456

	int secs;
	bitmap_counter_t *bmc;
	spin_lock_irq(&bitmap->lock);
	bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
	if (!bmc) {
1457
		spin_unlock_irq(&bitmap->lock);
1458
		return;
1459
	}
1460 1461
	if (! *bmc) {
		struct page *page;
1462
		*bmc = 1 | (needed?NEEDED_MASK:0);
1463 1464 1465 1466 1467 1468
		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);

1469 1470
}

1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493
/*
 * 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);
}

1494 1495 1496
/*
 * free memory that was allocated
 */
1497
static void bitmap_free(struct bitmap *bitmap)
1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521
{
	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);
}
1522 1523 1524 1525 1526 1527 1528 1529
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 */
1530 1531
	if (mddev->thread)
		mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1532 1533 1534

	bitmap_free(bitmap);
}
1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547

/*
 * 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;
1548
	sector_t start;
1549 1550 1551

	BUG_ON(sizeof(bitmap_super_t) != 256);

1552
	if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1553 1554
		return 0;

1555 1556
	BUG_ON(file && mddev->bitmap_offset);

1557
	bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568
	if (!bitmap)
		return -ENOMEM;

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

	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);
1569
	err = -ENOMEM;
1570
	if (!bitmap->write_pool)
1571
		goto error;
1572 1573

	bitmap->file = file;
1574 1575
	bitmap->offset = mddev->bitmap_offset;
	if (file) get_file(file);
1576 1577 1578
	/* read superblock from bitmap file (this sets bitmap->chunksize) */
	err = bitmap_read_sb(bitmap);
	if (err)
1579
		goto error;
1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597

	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;

1598
#ifdef INJECT_FATAL_FAULT_1
1599 1600
	bitmap->bp = NULL;
#else
1601
	bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1602
#endif
1603
	err = -ENOMEM;
1604
	if (!bitmap->bp)
1605
		goto error;
1606 1607 1608 1609 1610

	bitmap->flags |= BITMAP_ACTIVE;

	/* now that we have some pages available, initialize the in-memory
	 * bitmap from the on-disk bitmap */
1611 1612 1613 1614 1615 1616
	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);
1617

1618
	if (err)
1619
		goto error;
1620 1621 1622 1623

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

1624 1625
	mddev->bitmap = bitmap;

1626 1627 1628 1629 1630 1631 1632 1633 1634
	if (file)
		/* kick off the bitmap writeback daemon */
		bitmap->writeback_daemon =
			bitmap_start_daemon(bitmap,
					    bitmap_writeback_daemon,
					    "bitmap_wb");

	if (IS_ERR(bitmap->writeback_daemon))
		return PTR_ERR(bitmap->writeback_daemon);
1635 1636
	mddev->thread->timeout = bitmap->daemon_sleep * HZ;

1637
	return bitmap_update_sb(bitmap);
1638 1639 1640 1641

 error:
	bitmap_free(bitmap);
	return err;
1642 1643 1644 1645 1646 1647 1648 1649 1650 1651
}

/* 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);