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bitmap.c
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/*
* bitmap.c two-level bitmap (C) Peter T. Breuer ([email protected]) 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).
*/
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/init.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/seq_file.h>
#include "md.h"
#include "bitmap.h"
static inline char *bmname(struct bitmap *bitmap)
{
return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
}
/*
* 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_counts *bitmap,
unsigned long page, int create)
__releases(bitmap->lock)
__acquires(bitmap->lock)
{
unsigned char *mappage;
if (page >= bitmap->pages) {
/* This can happen if bitmap_start_sync goes beyond
* End-of-device while looking for a whole page.
* It is harmless.
*/
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;
/* this page has not been allocated yet */
spin_unlock_irq(&bitmap->lock);
mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
spin_lock_irq(&bitmap->lock);
if (mappage == NULL) {
pr_debug("md/bitmap: map page allocation failed, hijacking\n");
/* failed - set the hijacked flag so that we can use the
* pointer as a counter */
if (!bitmap->bp[page].map)
bitmap->bp[page].hijacked = 1;
} else if (bitmap->bp[page].map ||
bitmap->bp[page].hijacked) {
/* somebody beat us to getting the page */
kfree(mappage);
return 0;
} else {
/* no page was in place and we have one, so install it */
bitmap->bp[page].map = mappage;
bitmap->missing_pages--;
}
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 void bitmap_checkfree(struct bitmap_counts *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;
} else {
/* normal case, free the page */
ptr = bitmap->bp[page].map;
bitmap->bp[page].map = NULL;
bitmap->missing_pages++;
kfree(ptr);
}
}
/*
* bitmap file handling - read and write the bitmap file and its superblock
*/
/*
* basic page I/O operations
*/
/* IO operations when bitmap is stored near all superblocks */
static int read_sb_page(struct mddev *mddev, loff_t offset,
struct page *page,
unsigned long index, int size)
{
/* choose a good rdev and read the page from there */
struct md_rdev *rdev;
sector_t target;
rdev_for_each(rdev, mddev) {
if (! test_bit(In_sync, &rdev->flags)
|| test_bit(Faulty, &rdev->flags))
continue;
target = offset + index * (PAGE_SIZE/512);
if (sync_page_io(rdev, target,
roundup(size, bdev_logical_block_size(rdev->bdev)),
page, READ, true)) {
page->index = index;
return 0;
}
}
return -EIO;
}
static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
{
/* Iterate the disks of an mddev, using rcu to protect access to the
* linked list, and raising the refcount of devices we return to ensure
* they don't disappear while in use.
* As devices are only added or removed when raid_disk is < 0 and
* nr_pending is 0 and In_sync is clear, the entries we return will
* still be in the same position on the list when we re-enter
* list_for_each_continue_rcu.
*/
struct list_head *pos;
rcu_read_lock();
if (rdev == NULL)
/* start at the beginning */
pos = &mddev->disks;
else {
/* release the previous rdev and start from there. */
rdev_dec_pending(rdev, mddev);
pos = &rdev->same_set;
}
list_for_each_continue_rcu(pos, &mddev->disks) {
rdev = list_entry(pos, struct md_rdev, same_set);
if (rdev->raid_disk >= 0 &&
!test_bit(Faulty, &rdev->flags)) {
/* this is a usable devices */
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
return rdev;
}
}
rcu_read_unlock();
return NULL;
}
static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
{
struct md_rdev *rdev = NULL;
struct block_device *bdev;
struct mddev *mddev = bitmap->mddev;
struct bitmap_storage *store = &bitmap->storage;
while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
int size = PAGE_SIZE;
loff_t offset = mddev->bitmap_info.offset;
bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
if (page->index == store->file_pages-1) {
int last_page_size = store->bytes & (PAGE_SIZE-1);
if (last_page_size == 0)
last_page_size = PAGE_SIZE;
size = roundup(last_page_size,
bdev_logical_block_size(bdev));
}
/* Just make sure we aren't corrupting data or
* metadata
*/
if (mddev->external) {
/* Bitmap could be anywhere. */
if (rdev->sb_start + offset + (page->index
* (PAGE_SIZE/512))
> rdev->data_offset
&&
rdev->sb_start + offset
< (rdev->data_offset + mddev->dev_sectors
+ (PAGE_SIZE/512)))
goto bad_alignment;
} else if (offset < 0) {
/* DATA BITMAP METADATA */
if (offset
+ (long)(page->index * (PAGE_SIZE/512))
+ size/512 > 0)
/* bitmap runs in to metadata */
goto bad_alignment;
if (rdev->data_offset + mddev->dev_sectors
> rdev->sb_start + offset)
/* data runs in to bitmap */
goto bad_alignment;
} else if (rdev->sb_start < rdev->data_offset) {
/* METADATA BITMAP DATA */
if (rdev->sb_start
+ offset
+ page->index*(PAGE_SIZE/512) + size/512
> rdev->data_offset)
/* bitmap runs in to data */
goto bad_alignment;
} else {
/* DATA METADATA BITMAP - no problems */
}
md_super_write(mddev, rdev,
rdev->sb_start + offset
+ page->index * (PAGE_SIZE/512),
size,
page);
}
if (wait)
md_super_wait(mddev);
return 0;
bad_alignment:
return -EINVAL;
}
static void bitmap_file_kick(struct bitmap *bitmap);
/*
* write out a page to a file
*/
static void write_page(struct bitmap *bitmap, struct page *page, int wait)
{
struct buffer_head *bh;
if (bitmap->storage.file == NULL) {
switch (write_sb_page(bitmap, page, wait)) {
case -EINVAL:
set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
}
} else {
bh = page_buffers(page);
while (bh && bh->b_blocknr) {
atomic_inc(&bitmap->pending_writes);
set_buffer_locked(bh);
set_buffer_mapped(bh);
submit_bh(WRITE | REQ_SYNC, bh);
bh = bh->b_this_page;
}
if (wait)
wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes)==0);
}
if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
bitmap_file_kick(bitmap);
}
static void end_bitmap_write(struct buffer_head *bh, int uptodate)
{
struct bitmap *bitmap = bh->b_private;
if (!uptodate)
set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
if (atomic_dec_and_test(&bitmap->pending_writes))
wake_up(&bitmap->write_wait);
}
/* copied from buffer.c */
static void
__clear_page_buffers(struct page *page)
{
ClearPagePrivate(page);
set_page_private(page, 0);
page_cache_release(page);
}
static void free_buffers(struct page *page)
{
struct buffer_head *bh;
if (!PagePrivate(page))
return;
bh = page_buffers(page);
while (bh) {
struct buffer_head *next = bh->b_this_page;
free_buffer_head(bh);
bh = next;
}
__clear_page_buffers(page);
put_page(page);
}
/* read a page from a file.
* We both read the page, and attach buffers to the page to record the
* address of each block (using bmap). These addresses will be used
* to write the block later, completely bypassing the filesystem.
* This usage is similar to how swap files are handled, and allows us
* to write to a file with no concerns of memory allocation failing.
*/
static int read_page(struct file *file, unsigned long index,
struct bitmap *bitmap,
unsigned long count,
struct page *page)
{
int ret = 0;
struct inode *inode = file->f_path.dentry->d_inode;
struct buffer_head *bh;
sector_t block;
pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT);
bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
if (!bh) {
ret = -ENOMEM;
goto out;
}
attach_page_buffers(page, bh);
block = index << (PAGE_SHIFT - inode->i_blkbits);
while (bh) {
if (count == 0)
bh->b_blocknr = 0;
else {
bh->b_blocknr = bmap(inode, block);
if (bh->b_blocknr == 0) {
/* Cannot use this file! */
ret = -EINVAL;
goto out;
}
bh->b_bdev = inode->i_sb->s_bdev;
if (count < (1<<inode->i_blkbits))
count = 0;
else
count -= (1<<inode->i_blkbits);
bh->b_end_io = end_bitmap_write;
bh->b_private = bitmap;
atomic_inc(&bitmap->pending_writes);
set_buffer_locked(bh);
set_buffer_mapped(bh);
submit_bh(READ, bh);
}
block++;
bh = bh->b_this_page;
}
page->index = index;
wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes)==0);
if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
ret = -EIO;
out:
if (ret)
printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %d\n",
(int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT,
ret);
return ret;
}
/*
* bitmap file superblock operations
*/
/* update the event counter and sync the superblock to disk */
void bitmap_update_sb(struct bitmap *bitmap)
{
bitmap_super_t *sb;
if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
return;
if (bitmap->mddev->bitmap_info.external)
return;
if (!bitmap->storage.sb_page) /* no superblock */
return;
sb = kmap_atomic(bitmap->storage.sb_page);
sb->events = cpu_to_le64(bitmap->mddev->events);
if (bitmap->mddev->events < bitmap->events_cleared)
/* rocking back to read-only */
bitmap->events_cleared = bitmap->mddev->events;
sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
sb->state = cpu_to_le32(bitmap->flags);
/* Just in case these have been changed via sysfs: */
sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
/* This might have been changed by a reshape */
sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
bitmap_info.space);
kunmap_atomic(sb);
write_page(bitmap, bitmap->storage.sb_page, 1);
}
/* print out the bitmap file superblock */
void bitmap_print_sb(struct bitmap *bitmap)
{
bitmap_super_t *sb;
if (!bitmap || !bitmap->storage.sb_page)
return;
sb = kmap_atomic(bitmap->storage.sb_page);
printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
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",
*(__u32 *)(sb->uuid+0),
*(__u32 *)(sb->uuid+4),
*(__u32 *)(sb->uuid+8),
*(__u32 *)(sb->uuid+12));
printk(KERN_DEBUG " events: %llu\n",
(unsigned long long) le64_to_cpu(sb->events));
printk(KERN_DEBUG "events cleared: %llu\n",
(unsigned long long) le64_to_cpu(sb->events_cleared));
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);
printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
kunmap_atomic(sb);
}
/*
* bitmap_new_disk_sb
* @bitmap
*
* This function is somewhat the reverse of bitmap_read_sb. bitmap_read_sb
* reads and verifies the on-disk bitmap superblock and populates bitmap_info.
* This function verifies 'bitmap_info' and populates the on-disk bitmap
* structure, which is to be written to disk.
*
* Returns: 0 on success, -Exxx on error
*/
static int bitmap_new_disk_sb(struct bitmap *bitmap)
{
bitmap_super_t *sb;
unsigned long chunksize, daemon_sleep, write_behind;
int err = -EINVAL;
bitmap->storage.sb_page = alloc_page(GFP_KERNEL);
if (IS_ERR(bitmap->storage.sb_page)) {
err = PTR_ERR(bitmap->storage.sb_page);
bitmap->storage.sb_page = NULL;
return err;
}
bitmap->storage.sb_page->index = 0;
sb = kmap_atomic(bitmap->storage.sb_page);
sb->magic = cpu_to_le32(BITMAP_MAGIC);
sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
chunksize = bitmap->mddev->bitmap_info.chunksize;
BUG_ON(!chunksize);
if (!is_power_of_2(chunksize)) {
kunmap_atomic(sb);
printk(KERN_ERR "bitmap chunksize not a power of 2\n");
return -EINVAL;
}
sb->chunksize = cpu_to_le32(chunksize);
daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
if (!daemon_sleep ||
(daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
daemon_sleep = 5 * HZ;
}
sb->daemon_sleep = cpu_to_le32(daemon_sleep);
bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
/*
* FIXME: write_behind for RAID1. If not specified, what
* is a good choice? We choose COUNTER_MAX / 2 arbitrarily.
*/
write_behind = bitmap->mddev->bitmap_info.max_write_behind;
if (write_behind > COUNTER_MAX)
write_behind = COUNTER_MAX / 2;
sb->write_behind = cpu_to_le32(write_behind);
bitmap->mddev->bitmap_info.max_write_behind = write_behind;
/* keep the array size field of the bitmap superblock up to date */
sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
memcpy(sb->uuid, bitmap->mddev->uuid, 16);
set_bit(BITMAP_STALE, &bitmap->flags);
sb->state = cpu_to_le32(bitmap->flags);
bitmap->events_cleared = bitmap->mddev->events;
sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
kunmap_atomic(sb);
return 0;
}
/* 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;
unsigned long chunksize, daemon_sleep, write_behind;
unsigned long long events;
unsigned long sectors_reserved = 0;
int err = -EINVAL;
struct page *sb_page;
if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
chunksize = 128 * 1024 * 1024;
daemon_sleep = 5 * HZ;
write_behind = 0;
set_bit(BITMAP_STALE, &bitmap->flags);
err = 0;
goto out_no_sb;
}
/* page 0 is the superblock, read it... */
sb_page = alloc_page(GFP_KERNEL);
if (!sb_page)
return -ENOMEM;
bitmap->storage.sb_page = sb_page;
if (bitmap->storage.file) {
loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
err = read_page(bitmap->storage.file, 0,
bitmap, bytes, sb_page);
} else {
err = read_sb_page(bitmap->mddev,
bitmap->mddev->bitmap_info.offset,
sb_page,
0, sizeof(bitmap_super_t));
}
if (err)
return err;
sb = kmap_atomic(sb_page);
chunksize = le32_to_cpu(sb->chunksize);
daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
write_behind = le32_to_cpu(sb->write_behind);
sectors_reserved = le32_to_cpu(sb->sectors_reserved);
/* verify that the bitmap-specific fields are valid */
if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
reason = "bad magic";
else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
reason = "unrecognized superblock version";
else if (chunksize < 512)
reason = "bitmap chunksize too small";
else if (!is_power_of_2(chunksize))
reason = "bitmap chunksize not a power of 2";
else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
reason = "daemon sleep period out of range";
else if (write_behind > COUNTER_MAX)
reason = "write-behind limit out of range (0 - 16383)";
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) {
/*
* We have a persistent array superblock, so 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);
set_bit(BITMAP_STALE, &bitmap->flags);
}
}
/* assign fields using values from superblock */
bitmap->flags |= le32_to_cpu(sb->state);
if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
err = 0;
out:
kunmap_atomic(sb);
out_no_sb:
if (test_bit(BITMAP_STALE, &bitmap->flags))
bitmap->events_cleared = bitmap->mddev->events;
bitmap->mddev->bitmap_info.chunksize = chunksize;
bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
bitmap->mddev->bitmap_info.max_write_behind = write_behind;
if (bitmap->mddev->bitmap_info.space == 0 ||
bitmap->mddev->bitmap_info.space > sectors_reserved)
bitmap->mddev->bitmap_info.space = sectors_reserved;
if (err)
bitmap_print_sb(bitmap);
return err;
}
/*
* general bitmap file operations
*/
/*
* on-disk bitmap:
*
* Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
* file a page at a time. There's a superblock at the start of the file.
*/
/* calculate the index of the page that contains this bit */
static inline unsigned long file_page_index(struct bitmap_storage *store,
unsigned long chunk)
{
if (store->sb_page)
chunk += sizeof(bitmap_super_t) << 3;
return chunk >> PAGE_BIT_SHIFT;
}
/* calculate the (bit) offset of this bit within a page */
static inline unsigned long file_page_offset(struct bitmap_storage *store,
unsigned long chunk)
{
if (store->sb_page)
chunk += sizeof(bitmap_super_t) << 3;
return 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_storage *store,
unsigned long chunk)
{
if (file_page_index(store, chunk) >= store->file_pages)
return NULL;
return store->filemap[file_page_index(store, chunk)
- file_page_index(store, 0)];
}
static int bitmap_storage_alloc(struct bitmap_storage *store,
unsigned long chunks, int with_super)
{
int pnum;
unsigned long num_pages;
unsigned long bytes;
bytes = DIV_ROUND_UP(chunks, 8);
if (with_super)
bytes += sizeof(bitmap_super_t);
num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
store->filemap = kmalloc(sizeof(struct page *)
* num_pages, GFP_KERNEL);
if (!store->filemap)
return -ENOMEM;
if (with_super && !store->sb_page) {
store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
if (store->sb_page == NULL)
return -ENOMEM;
store->sb_page->index = 0;
}
pnum = 0;
if (store->sb_page) {
store->filemap[0] = store->sb_page;
pnum = 1;
}
for ( ; pnum < num_pages; pnum++) {
store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
if (!store->filemap[pnum]) {
store->file_pages = pnum;
return -ENOMEM;
}
store->filemap[pnum]->index = pnum;
}
store->file_pages = pnum;
/* We need 4 bits per page, rounded up to a multiple
* of sizeof(unsigned long) */
store->filemap_attr = kzalloc(
roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
GFP_KERNEL);
if (!store->filemap_attr)
return -ENOMEM;
store->bytes = bytes;
return 0;
}
static void bitmap_file_unmap(struct bitmap_storage *store)
{
struct page **map, *sb_page;
int pages;
struct file *file;
file = store->file;
map = store->filemap;
pages = store->file_pages;
sb_page = store->sb_page;
while (pages--)
if (map[pages] != sb_page) /* 0 is sb_page, release it below */
free_buffers(map[pages]);
kfree(map);
kfree(store->filemap_attr);
if (sb_page)
free_buffers(sb_page);
if (file) {
struct inode *inode = file->f_path.dentry->d_inode;
invalidate_mapping_pages(inode->i_mapping, 0, -1);
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;
if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
bitmap_update_sb(bitmap);
if (bitmap->storage.file) {
path = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (path)
ptr = d_path(&bitmap->storage.file->f_path,
path, PAGE_SIZE);
printk(KERN_ALERT
"%s: kicking failed bitmap file %s from array!\n",
bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
kfree(path);
} else
printk(KERN_ALERT
"%s: disabling internal bitmap due to errors\n",
bmname(bitmap));
}
}
enum bitmap_page_attr {
BITMAP_PAGE_DIRTY = 0, /* there are set bits that need to be synced */
BITMAP_PAGE_PENDING = 1, /* there are bits that are being cleaned.
* i.e. counter is 1 or 2. */
BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
};
static inline void set_page_attr(struct bitmap *bitmap, int pnum,
enum bitmap_page_attr attr)
{
set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
}
static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
enum bitmap_page_attr attr)
{
clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
}
static inline int test_page_attr(struct bitmap *bitmap, int pnum,
enum bitmap_page_attr attr)
{
return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
}
static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
enum bitmap_page_attr attr)
{
return test_and_clear_bit((pnum<<2) + attr,
bitmap->storage.filemap_attr);
}
/*
* 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 >> bitmap->counts.chunkshift;
page = filemap_get_page(&bitmap->storage, chunk);
if (!page)
return;
bit = file_page_offset(&bitmap->storage, chunk);
/* set the bit */
kaddr = kmap_atomic(page);
if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
set_bit(bit, kaddr);
else
test_and_set_bit_le(bit, kaddr);
kunmap_atomic(kaddr);
pr_debug("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->index, BITMAP_PAGE_DIRTY);
}
static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
{
unsigned long bit;
struct page *page;
void *paddr;
unsigned long chunk = block >> bitmap->counts.chunkshift;
page = filemap_get_page(&bitmap->storage, chunk);
if (!page)
return;
bit = file_page_offset(&bitmap->storage, chunk);
paddr = kmap_atomic(page);
if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
clear_bit(bit, paddr);
else
test_and_clear_bit_le(bit, paddr);
kunmap_atomic(paddr);
if (!test_page_attr(bitmap, page->index, BITMAP_PAGE_NEEDWRITE)) {
set_page_attr(bitmap, page->index, BITMAP_PAGE_PENDING);
bitmap->allclean = 0;
}
}
/* 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 */
void bitmap_unplug(struct bitmap *bitmap)
{
unsigned long i;
int dirty, need_write;
int wait = 0;
if (!bitmap || !bitmap->storage.filemap ||
test_bit(BITMAP_STALE, &bitmap->flags))
return;
/* 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->storage.file_pages; i++) {
if (!bitmap->storage.filemap)
return;
dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
need_write = test_and_clear_page_attr(bitmap, i,
BITMAP_PAGE_NEEDWRITE);
if (dirty || need_write) {
clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
write_page(bitmap, bitmap->storage.filemap[i], 0);
}
if (dirty)
wait = 1;
}
if (wait) { /* if any writes were performed, we need to wait on them */
if (bitmap->storage.file)
wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes)==0);
else
md_super_wait(bitmap->mddev);
}
if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
bitmap_file_kick(bitmap);
}
EXPORT_SYMBOL(bitmap_unplug);
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
/* * 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.
*
* We ignore all bits for sectors that end earlier than 'start'.
* This is used when reading an out-of-date bitmap...
*/
static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
{
unsigned long i, chunks, index, oldindex, bit;
struct page *page = NULL;
unsigned long bit_cnt = 0;
struct file *file;
unsigned long offset;
int outofdate;
int ret = -ENOSPC;
void *paddr;
struct bitmap_storage *store = &bitmap->storage;
chunks = bitmap->counts.chunks;
file = store->file;
if (!file && !bitmap->mddev->bitmap_info.offset) {
/* No permanent bitmap - fill with '1s'. */
store->filemap = NULL;
store->file_pages = 0;
for (i = 0; i < chunks ; i++) {
/* if the disk bit is set, set the memory bit */
int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
>= start);
bitmap_set_memory_bits(bitmap,
(sector_t)i << bitmap->counts.chunkshift,
needed);
}
return 0;
}
outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
if (outofdate)
printk(KERN_INFO "%s: bitmap file is out of date, doing full "
"recovery\n", bmname(bitmap));
if (file && i_size_read(file->f_mapping->host) < store->bytes) {
printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
bmname(bitmap),
(unsigned long) i_size_read(file->f_mapping->host),
store->bytes);
goto err;
}
oldindex = ~0L;
offset = 0;
if (!bitmap->mddev->bitmap_info.external)
offset = sizeof(bitmap_super_t);
for (i = 0; i < chunks; i++) {
int b;
index = file_page_index(&bitmap->storage, i);
bit = file_page_offset(&bitmap->storage, i);
if (index != oldindex) { /* this is a new page, read it in */
int count;
/* unmap the old page, we're done with it */
if (index == store->file_pages-1)
count = store->bytes - index * PAGE_SIZE;
else
count = PAGE_SIZE;
page = store->filemap[index];
if (file)
ret = read_page(file, index, bitmap,
count, page);