--- /dev/null
+/*
+ * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
+ *
+ * bitmap_create - sets up the bitmap structure
+ * bitmap_destroy - destroys the bitmap structure
+ *
+ * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
+ * - added disk storage for bitmap
+ * - changes to allow various bitmap chunk sizes
+ * - added bitmap daemon (to asynchronously clear bitmap bits from disk)
+ */
+
+/*
+ * Still to do:
+ *
+ * flush after percent set rather than just time based. (maybe both).
+ * wait if count gets too high, wake when it drops to half.
+ * allow bitmap to be mirrored with superblock (before or after...)
+ * allow hot-add to re-instate a current device.
+ * allow hot-add of bitmap after quiessing device
+ */
+
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/config.h>
+#include <linux/timer.h>
+#include <linux/sched.h>
+#include <linux/list.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/buffer_head.h>
+#include <linux/raid/md.h>
+#include <linux/raid/bitmap.h>
+
+/* debug macros */
+
+#define DEBUG 0
+
+#if DEBUG
+/* these are for debugging purposes only! */
+
+/* define one and only one of these */
+#define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
+#define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
+#define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
+#define INJECT_FAULTS_4 0 /* undef */
+#define INJECT_FAULTS_5 0 /* undef */
+#define INJECT_FAULTS_6 0
+
+/* if these are defined, the driver will fail! debug only */
+#define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
+#define INJECT_FATAL_FAULT_2 0 /* undef */
+#define INJECT_FATAL_FAULT_3 0 /* undef */
+#endif
+
+//#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
+#define DPRINTK(x...) do { } while(0)
+
+#ifndef PRINTK
+# if DEBUG > 0
+# define PRINTK(x...) printk(KERN_DEBUG x)
+# else
+# define PRINTK(x...)
+# endif
+#endif
+
+static inline char * bmname(struct bitmap *bitmap)
+{
+ return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
+}
+
+
+/*
+ * test if the bitmap is active
+ */
+int bitmap_active(struct bitmap *bitmap)
+{
+ unsigned long flags;
+ int res = 0;
+
+ if (!bitmap)
+ return res;
+ spin_lock_irqsave(&bitmap->lock, flags);
+ res = bitmap->flags & BITMAP_ACTIVE;
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ return res;
+}
+
+#define WRITE_POOL_SIZE 256
+/* mempool for queueing pending writes on the bitmap file */
+static void *write_pool_alloc(unsigned int gfp_flags, void *data)
+{
+ return kmalloc(sizeof(struct page_list), gfp_flags);
+}
+
+static void write_pool_free(void *ptr, void *data)
+{
+ kfree(ptr);
+}
+
+/*
+ * just a placeholder - calls kmalloc for bitmap pages
+ */
+static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
+{
+ unsigned char *page;
+
+#if INJECT_FAULTS_1
+ page = NULL;
+#else
+ page = kmalloc(PAGE_SIZE, GFP_NOIO);
+#endif
+ if (!page)
+ printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
+ else
+ printk("%s: bitmap_alloc_page: allocated page at %p\n",
+ 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
+ */
+
+/*
+ * write out a page
+ */
+static int write_page(struct page *page, int wait)
+{
+ int ret = -ENOMEM;
+
+ lock_page(page);
+
+ if (page->mapping == NULL)
+ goto unlock_out;
+ else if (i_size_read(page->mapping->host) < page->index << PAGE_SHIFT) {
+ ret = -ENOENT;
+ goto unlock_out;
+ }
+
+ ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
+ if (!ret)
+ ret = page->mapping->a_ops->commit_write(NULL, page, 0,
+ PAGE_SIZE);
+ if (ret) {
+unlock_out:
+ unlock_page(page);
+ return ret;
+ }
+
+ set_page_dirty(page); /* force it to be written out */
+ return write_one_page(page, wait);
+}
+
+/* read a page from a file, pinning it into cache, and return bytes_read */
+static struct page *read_page(struct file *file, unsigned long index,
+ unsigned long *bytes_read)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct page *page = NULL;
+ loff_t isize = i_size_read(inode);
+ unsigned long end_index = isize >> PAGE_CACHE_SHIFT;
+
+ PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_CACHE_SIZE,
+ (unsigned long long)index << PAGE_CACHE_SHIFT);
+
+ page = read_cache_page(inode->i_mapping, index,
+ (filler_t *)inode->i_mapping->a_ops->readpage, file);
+ if (IS_ERR(page))
+ goto out;
+ wait_on_page_locked(page);
+ if (!PageUptodate(page) || PageError(page)) {
+ page_cache_release(page);
+ page = ERR_PTR(-EIO);
+ goto out;
+ }
+
+ if (index > end_index) /* we have read beyond EOF */
+ *bytes_read = 0;
+ else if (index == end_index) /* possible short read */
+ *bytes_read = isize & ~PAGE_CACHE_MASK;
+ else
+ *bytes_read = PAGE_CACHE_SIZE; /* got a full page */
+out:
+ if (IS_ERR(page))
+ printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
+ (int)PAGE_CACHE_SIZE,
+ (unsigned long long)index << PAGE_CACHE_SHIFT,
+ PTR_ERR(page));
+ return page;
+}
+
+/*
+ * bitmap file superblock operations
+ */
+
+/* update the event counter and sync the superblock to disk */
+int bitmap_update_sb(struct bitmap *bitmap)
+{
+ bitmap_super_t *sb;
+ unsigned long flags;
+
+ if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
+ return 0;
+ spin_lock_irqsave(&bitmap->lock, flags);
+ if (!bitmap->sb_page) { /* no superblock */
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ return 0;
+ }
+ page_cache_get(bitmap->sb_page);
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ sb = (bitmap_super_t *)kmap(bitmap->sb_page);
+ sb->events = cpu_to_le64(bitmap->mddev->events);
+ if (!bitmap->mddev->degraded)
+ sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+ kunmap(bitmap->sb_page);
+ write_page(bitmap->sb_page, 0);
+ return 0;
+}
+
+/* print out the bitmap file superblock */
+void bitmap_print_sb(struct bitmap *bitmap)
+{
+ bitmap_super_t *sb;
+
+ if (!bitmap || !bitmap->sb_page)
+ return;
+ sb = (bitmap_super_t *)kmap(bitmap->sb_page);
+ printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
+ 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_clred: %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", le64_to_cpu(sb->sync_size));
+ kunmap(bitmap->sb_page);
+}
+
+/* read the superblock from the bitmap file and initialize some bitmap fields */
+static int bitmap_read_sb(struct bitmap *bitmap)
+{
+ char *reason = NULL;
+ bitmap_super_t *sb;
+ unsigned long chunksize, daemon_sleep;
+ unsigned long bytes_read;
+ unsigned long long events;
+ int err = -EINVAL;
+
+ /* page 0 is the superblock, read it... */
+ bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
+ if (IS_ERR(bitmap->sb_page)) {
+ err = PTR_ERR(bitmap->sb_page);
+ bitmap->sb_page = NULL;
+ return err;
+ }
+
+ sb = (bitmap_super_t *)kmap(bitmap->sb_page);
+
+ if (bytes_read < sizeof(*sb)) { /* short read */
+ printk(KERN_INFO "%s: bitmap file superblock truncated\n",
+ bmname(bitmap));
+ err = -ENOSPC;
+ goto out;
+ }
+
+ chunksize = le32_to_cpu(sb->chunksize);
+ daemon_sleep = le32_to_cpu(sb->daemon_sleep);
+
+ /* verify that the bitmap-specific fields are valid */
+ if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
+ reason = "bad magic";
+ else if (sb->version != cpu_to_le32(BITMAP_MAJOR))
+ reason = "unrecognized superblock version";
+ else if (chunksize < 512 || chunksize > (1024 * 1024 * 4))
+ reason = "bitmap chunksize out of range (512B - 4MB)";
+ else if ((1 << ffz(~chunksize)) != chunksize)
+ reason = "bitmap chunksize not a power of 2";
+ else if (daemon_sleep < 1 || daemon_sleep > 15)
+ reason = "daemon sleep period out of range";
+ 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;
+ bitmap->flags |= sb->state;
+ bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
+ err = 0;
+out:
+ kunmap(bitmap->sb_page);
+ if (err)
+ bitmap_print_sb(bitmap);
+ return err;
+}
+
+enum bitmap_mask_op {
+ MASK_SET,
+ MASK_UNSET
+};
+
+/* record the state of the bitmap in the superblock */
+static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
+ enum bitmap_mask_op op)
+{
+ bitmap_super_t *sb;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bitmap->lock, flags);
+ if (!bitmap || !bitmap->sb_page) { /* can't set the state */
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ return;
+ }
+ page_cache_get(bitmap->sb_page);
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ sb = (bitmap_super_t *)kmap(bitmap->sb_page);
+ switch (op) {
+ case MASK_SET: sb->state |= bits;
+ break;
+ case MASK_UNSET: sb->state &= ~bits;
+ break;
+ default: BUG();
+ }
+ kunmap(bitmap->sb_page);
+ page_cache_release(bitmap->sb_page);
+}
+
+/*
+ * general bitmap file operations
+ */
+
+/* calculate the index of the page that contains this bit */
+static inline unsigned long file_page_index(unsigned long chunk)
+{
+ return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
+}
+
+/* calculate the (bit) offset of this bit within a page */
+static inline unsigned long file_page_offset(unsigned long chunk)
+{
+ return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
+}
+
+/*
+ * return a pointer to the page in the filemap that contains the given bit
+ *
+ * this lookup is complicated by the fact that the bitmap sb might be exactly
+ * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
+ * 0 or page 1
+ */
+static inline struct page *filemap_get_page(struct bitmap *bitmap,
+ unsigned long chunk)
+{
+ return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
+}
+
+
+static void bitmap_file_unmap(struct bitmap *bitmap)
+{
+ struct page **map, *sb_page;
+ unsigned long *attr;
+ int pages;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bitmap->lock, flags);
+ map = bitmap->filemap;
+ bitmap->filemap = NULL;
+ attr = bitmap->filemap_attr;
+ bitmap->filemap_attr = NULL;
+ pages = bitmap->file_pages;
+ bitmap->file_pages = 0;
+ sb_page = bitmap->sb_page;
+ bitmap->sb_page = NULL;
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+
+ while (pages--)
+ if (map[pages]->index != 0) /* 0 is sb_page, release it below */
+ page_cache_release(map[pages]);
+ kfree(map);
+ kfree(attr);
+
+ if (sb_page)
+ page_cache_release(sb_page);
+}
+
+static void bitmap_stop_daemons(struct bitmap *bitmap);
+
+/* dequeue the next item in a page list -- don't call from irq context */
+static struct page_list *dequeue_page(struct bitmap *bitmap,
+ struct list_head *head)
+{
+ struct page_list *item = NULL;
+
+ 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 list_head *queues[] = { &bitmap->complete_pages, NULL };
+ struct list_head *head;
+ struct page_list *item;
+ int i;
+
+ for (i = 0; queues[i]; i++) {
+ head = queues[i];
+ while ((item = dequeue_page(bitmap, head))) {
+ page_cache_release(item->page);
+ mempool_free(item, bitmap->write_pool);
+ }
+ }
+
+ spin_lock(&bitmap->write_lock);
+ bitmap->writes_pending = 0; /* make sure waiters continue */
+ wake_up(&bitmap->write_wait);
+ spin_unlock(&bitmap->write_lock);
+}
+
+static void bitmap_file_put(struct bitmap *bitmap)
+{
+ struct file *file;
+ struct inode *inode;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bitmap->lock, flags);
+ file = bitmap->file;
+ bitmap->file = NULL;
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+
+ bitmap_stop_daemons(bitmap);
+
+ drain_write_queues(bitmap);
+
+ bitmap_file_unmap(bitmap);
+
+ if (file) {
+ inode = file->f_mapping->host;
+ spin_lock(&inode->i_lock);
+ atomic_set(&inode->i_writecount, 1); /* allow writes again */
+ spin_unlock(&inode->i_lock);
+ fput(file);
+ }
+}
+
+
+/*
+ * bitmap_file_kick - if an error occurs while manipulating the bitmap file
+ * then it is no longer reliable, so we stop using it and we mark the file
+ * as failed in the superblock
+ */
+static void bitmap_file_kick(struct bitmap *bitmap)
+{
+ char *path, *ptr = NULL;
+
+ bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
+ bitmap_update_sb(bitmap);
+
+ path = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (path)
+ ptr = file_path(bitmap->file, path, PAGE_SIZE);
+
+ printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
+ bmname(bitmap), ptr ? ptr : "");
+
+ kfree(path);
+
+ 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);
+
+ if (!bitmap->file || !bitmap->filemap) {
+ return;
+ }
+
+ page = filemap_get_page(bitmap, chunk);
+ bit = file_page_offset(chunk);
+
+
+ /* make sure the page stays cached until it gets written out */
+ if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
+ page_cache_get(page);
+
+ /* set the bit */
+ kaddr = kmap_atomic(page, KM_USER0);
+ set_bit(bit, kaddr);
+ kunmap_atomic(kaddr, KM_USER0);
+ PRINTK("set file bit %lu page %lu\n", bit, page->index);
+
+ /* record page number so it gets flushed to disk when unplug occurs */
+ set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
+
+}
+
+/* this gets called when the md device is ready to unplug its underlying
+ * (slave) device queues -- before we let any writes go down, we need to
+ * sync the dirty pages of the bitmap file to disk */
+int bitmap_unplug(struct bitmap *bitmap)
+{
+ unsigned long i, attr, flags;
+ struct page *page;
+ int wait = 0;
+
+ 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);
+ if (!bitmap->file || !bitmap->filemap) {
+ 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);
+
+ if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE))
+ write_page(page, 0);
+ }
+ if (wait) { /* if any writes were performed, we need to wait on them */
+ spin_lock_irq(&bitmap->write_lock);
+ wait_event_lock_irq(bitmap->write_wait,
+ bitmap->writes_pending == 0, bitmap->write_lock,
+ wake_up_process(bitmap->writeback_daemon->tsk));
+ spin_unlock_irq(&bitmap->write_lock);
+ }
+ return 0;
+}
+
+static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
+ unsigned long sectors, int set);
+/* * 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.
+ */
+static int bitmap_init_from_disk(struct bitmap *bitmap)
+{
+ unsigned long i, chunks, index, oldindex, bit;
+ struct page *page = NULL, *oldpage = NULL;
+ unsigned long num_pages, bit_cnt = 0;
+ struct file *file;
+ unsigned long bytes, offset, dummy;
+ int outofdate;
+ int ret = -ENOSPC;
+
+ chunks = bitmap->chunks;
+ file = bitmap->file;
+
+ if (!file) { /* no file, dirty all the in-memory bits */
+ printk(KERN_INFO "%s: no bitmap file, doing full recovery\n",
+ bmname(bitmap));
+ bitmap_set_memory_bits(bitmap, 0,
+ chunks << CHUNK_BLOCK_SHIFT(bitmap), 1);
+ return 0;
+ }
+
+#if INJECT_FAULTS_3
+ 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;
+ num_pages = (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
+ if (i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
+ 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;
+ }
+ num_pages++;
+ bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
+ if (!bitmap->filemap) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ bitmap->filemap_attr = kmalloc(sizeof(long) * num_pages, GFP_KERNEL);
+ if (!bitmap->filemap_attr) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ memset(bitmap->filemap_attr, 0, sizeof(long) * num_pages);
+
+ oldindex = ~0L;
+
+ for (i = 0; i < chunks; i++) {
+ index = file_page_index(i);
+ bit = file_page_offset(i);
+ if (index != oldindex) { /* this is a new page, read it in */
+ /* unmap the old page, we're done with it */
+ if (oldpage != NULL)
+ kunmap(oldpage);
+ if (index == 0) {
+ /*
+ * if we're here then the superblock page
+ * contains some bits (PAGE_SIZE != sizeof sb)
+ * we've already read it in, so just use it
+ */
+ page = bitmap->sb_page;
+ offset = sizeof(bitmap_super_t);
+ } else {
+ page = read_page(file, index, &dummy);
+ if (IS_ERR(page)) { /* read error */
+ ret = PTR_ERR(page);
+ goto out;
+ }
+ offset = 0;
+ }
+ oldindex = index;
+ oldpage = page;
+ kmap(page);
+
+ if (outofdate) {
+ /*
+ * if bitmap is out of date, dirty the
+ * whole page and write it out
+ */
+ memset(page_address(page) + offset, 0xff,
+ PAGE_SIZE - offset);
+ ret = write_page(page, 1);
+ if (ret) {
+ kunmap(page);
+ /* release, page not in filemap yet */
+ page_cache_release(page);
+ goto out;
+ }
+ }
+
+ bitmap->filemap[bitmap->file_pages++] = page;
+ }
+ if (test_bit(bit, page_address(page))) {
+ /* if the disk bit is set, set the memory bit */
+ bitmap_set_memory_bits(bitmap,
+ i << CHUNK_BLOCK_SHIFT(bitmap), 1, 1);
+ bit_cnt++;
+ }
+#if 0
+ else
+ bitmap_set_memory_bits(bitmap,
+ i << CHUNK_BLOCK_SHIFT(bitmap), 1, 0);
+#endif
+ }
+
+ /* everything went OK */
+ ret = 0;
+ bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
+
+ if (page) /* unmap the last page */
+ kunmap(page);
+
+ if (bit_cnt) { /* Kick recovery if any bits were set */
+ set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
+ md_wakeup_thread(bitmap->mddev->thread);
+ }
+
+out:
+ printk(KERN_INFO "%s: bitmap initialized from disk: "
+ "read %lu/%lu pages, set %lu bits, status: %d\n",
+ bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
+
+ return ret;
+}
+
+
+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)
+{
+ unsigned long bit, j;
+ unsigned long flags;
+ struct page *page = NULL, *lastpage = NULL;
+ int err = 0;
+ int blocks;
+ int attr;
+
+ if (bitmap == NULL)
+ return 0;
+ if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
+ return 0;
+ bitmap->daemon_lastrun = jiffies;
+
+ for (j = 0; j < bitmap->chunks; j++) {
+ bitmap_counter_t *bmc;
+ spin_lock_irqsave(&bitmap->lock, flags);
+ if (!bitmap->file || !bitmap->filemap) {
+ /* error or shutdown */
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ break;
+ }
+
+ page = filemap_get_page(bitmap, j);
+ /* skip this page unless it's marked as needing cleaning */
+ if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
+ if (attr & BITMAP_PAGE_NEEDWRITE) {
+ page_cache_get(page);
+ clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
+ }
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ if (attr & BITMAP_PAGE_NEEDWRITE) {
+ if (write_page(page, 0))
+ bitmap_file_kick(bitmap);
+ page_cache_release(page);
+ }
+ continue;
+ }
+
+ bit = file_page_offset(j);
+
+ if (page != lastpage) {
+ /* grab the new page, sync and release the old */
+ page_cache_get(page);
+ if (lastpage != NULL) {
+ if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
+ clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ write_page(lastpage, 0);
+ } else {
+ set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ }
+ kunmap(lastpage);
+ page_cache_release(lastpage);
+ if (err)
+ bitmap_file_kick(bitmap);
+ } else
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ lastpage = page;
+ kmap(page);
+/*
+ printk("bitmap clean at page %lu\n", j);
+*/
+ spin_lock_irqsave(&bitmap->lock, flags);
+ clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
+ }
+ bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
+ &blocks, 0);
+ if (bmc) {
+/*
+ if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
+*/
+ if (*bmc == 2) {
+ *bmc=1; /* maybe clear the bit next time */
+ set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
+ } else if (*bmc == 1) {
+ /* we can clear the bit */
+ *bmc = 0;
+ bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
+ -1);
+
+ /* clear the bit */
+ clear_bit(bit, page_address(page));
+ }
+ }
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ }
+
+ /* now sync the final page */
+ if (lastpage != NULL) {
+ kunmap(lastpage);
+ spin_lock_irqsave(&bitmap->lock, flags);
+ if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
+ clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ write_page(lastpage, 0);
+ } else {
+ set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ }
+
+ page_cache_release(lastpage);
+ }
+
+ return err;
+}
+
+static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
+{
+ mdk_thread_t *dmn;
+ unsigned long flags;
+
+ /* if no one is waiting on us, we'll free the md thread struct
+ * and exit, otherwise we let the waiter clean things up */
+ spin_lock_irqsave(&bitmap->lock, flags);
+ if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
+ *daemon = NULL;
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ kfree(dmn);
+ complete_and_exit(NULL, 0); /* do_exit not exported */
+ }
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+}
+
+static void bitmap_writeback_daemon(mddev_t *mddev)
+{
+ struct bitmap *bitmap = mddev->bitmap;
+ struct page *page;
+ struct page_list *item;
+ int err = 0;
+
+ while (1) {
+ PRINTK("%s: bitmap writeback daemon waiting...\n", bmname(bitmap));
+ down_interruptible(&bitmap->write_done);
+ if (signal_pending(current)) {
+ printk(KERN_INFO
+ "%s: bitmap writeback daemon got signal, exiting...\n",
+ bmname(bitmap));
+ break;
+ }
+
+ PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
+ /* wait on bitmap page writebacks */
+ while ((item = dequeue_page(bitmap, &bitmap->complete_pages))) {
+ page = item->page;
+ mempool_free(item, bitmap->write_pool);
+ PRINTK("wait on page writeback: %p %lu\n", page, bitmap->writes_pending);
+ wait_on_page_writeback(page);
+ PRINTK("finished page writeback: %p %lu\n", page, bitmap->writes_pending);
+ spin_lock(&bitmap->write_lock);
+ if (!--bitmap->writes_pending)
+ wake_up(&bitmap->write_wait);
+ spin_unlock(&bitmap->write_lock);
+ err = PageError(page);
+ page_cache_release(page);
+ if (err) {
+ printk(KERN_WARNING "%s: bitmap file writeback "
+ "failed (page %lu): %d\n",
+ bmname(bitmap), page->index, err);
+ bitmap_file_kick(bitmap);
+ goto out;
+ }
+ }
+ }
+out:
+ if (err) {
+ printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
+ bmname(bitmap), err);
+ daemon_exit(bitmap, &bitmap->writeback_daemon);
+ }
+ return;
+}
+
+static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
+ void (*func)(mddev_t *), char *name)
+{
+ mdk_thread_t *daemon;
+ unsigned long flags;
+ char namebuf[32];
+
+ spin_lock_irqsave(&bitmap->lock, flags);
+ *ptr = NULL;
+ if (!bitmap->file) /* no need for daemon if there's no backing file */
+ goto out_unlock;
+
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+
+#if INJECT_FATAL_FAULT_2
+ daemon = NULL;
+#else
+ sprintf(namebuf, "%%s_%s", name);
+ daemon = md_register_thread(func, bitmap->mddev, namebuf);
+#endif
+ if (!daemon) {
+ printk(KERN_ERR "%s: failed to start bitmap daemon\n",
+ bmname(bitmap));
+ return -ECHILD;
+ }
+
+ spin_lock_irqsave(&bitmap->lock, flags);
+ *ptr = daemon;
+
+ md_wakeup_thread(daemon); /* start it running */
+
+ PRINTK("%s: %s daemon (pid %d) started...\n",
+ bmname(bitmap), name, bitmap->daemon->tsk->pid);
+out_unlock:
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ return 0;
+}
+
+static int bitmap_start_daemons(struct bitmap *bitmap)
+{
+ int err = bitmap_start_daemon(bitmap, &bitmap->writeback_daemon,
+ bitmap_writeback_daemon, "bitmap_wb");
+ return err;
+}
+
+static void bitmap_stop_daemon(struct bitmap *bitmap, mdk_thread_t **ptr)
+{
+ mdk_thread_t *daemon;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bitmap->lock, flags);
+ daemon = *ptr;
+ *ptr = NULL;
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ if (daemon)
+ md_unregister_thread(daemon); /* destroy the thread */
+}
+
+static void bitmap_stop_daemons(struct bitmap *bitmap)
+{
+ /* the daemons can't stop themselves... they'll just exit instead... */
+ if (bitmap->writeback_daemon &&
+ current->pid != bitmap->writeback_daemon->tsk->pid)
+ bitmap_stop_daemon(bitmap, &bitmap->writeback_daemon);
+}
+
+static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
+ sector_t offset, int *blocks,
+ int create)
+{
+ /* If 'create', we might release the lock and reclaim it.
+ * The lock must have been taken with interrupts enabled.
+ * If !create, we don't release the lock.
+ */
+ sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
+ unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
+ unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
+ sector_t csize;
+
+ if (bitmap_checkpage(bitmap, page, create) < 0) {
+ csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
+ *blocks = csize - (offset & (csize- 1));
+ return NULL;
+ }
+ /* now locked ... */
+
+ if (bitmap->bp[page].hijacked) { /* hijacked pointer */
+ /* should we use the first or second counter field
+ * of the hijacked pointer? */
+ int hi = (pageoff > PAGE_COUNTER_MASK);
+ csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
+ PAGE_COUNTER_SHIFT - 1);
+ *blocks = csize - (offset & (csize- 1));
+ return &((bitmap_counter_t *)
+ &bitmap->bp[page].map)[hi];
+ } else { /* page is allocated */
+ csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
+ *blocks = csize - (offset & (csize- 1));
+ return (bitmap_counter_t *)
+ &(bitmap->bp[page].map[pageoff]);
+ }
+}
+
+int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors)
+{
+ if (!bitmap) return 0;
+ 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,
+ int success)
+{
+ if (!bitmap) return;
+ 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;
+ }
+}
+
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks)
+{
+ 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;
+ *bmc |= RESYNC_MASK;
+ *bmc &= ~NEEDED_MASK;
+ }
+ }
+ 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;
+ }
+}
+
+static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
+ unsigned long sectors, int set)
+{
+ /* For each chunk covered by any of these sectors, set the
+ * resync needed bit, and the counter to 1. They should all
+ * be 0 at this point
+ */
+ while (sectors) {
+ int secs;
+ bitmap_counter_t *bmc;
+ spin_lock_irq(&bitmap->lock);
+ bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
+ if (!bmc) {
+ spin_unlock_irq(&bitmap->lock);
+ return;
+ }
+ if (set && !NEEDED(*bmc)) {
+ BUG_ON(*bmc);
+ *bmc = NEEDED_MASK | 1;
+ bitmap_count_page(bitmap, offset, 1);
+ }
+ spin_unlock_irq(&bitmap->lock);
+ if (sectors > secs)
+ sectors -= secs;
+ else
+ sectors = 0;
+ }
+}
+
+/* dirty the entire bitmap */
+int bitmap_setallbits(struct bitmap *bitmap)
+{
+ unsigned long flags;
+ unsigned long j;
+
+ /* dirty the in-memory bitmap */
+ bitmap_set_memory_bits(bitmap, 0, bitmap->chunks << CHUNK_BLOCK_SHIFT(bitmap), 1);
+
+ /* dirty the bitmap file */
+ for (j = 0; j < bitmap->file_pages; j++) {
+ struct page *page = bitmap->filemap[j];
+
+ spin_lock_irqsave(&bitmap->lock, flags);
+ page_cache_get(page);
+ spin_unlock_irqrestore(&bitmap->lock, flags);
+ memset(kmap(page), 0xff, PAGE_SIZE);
+ kunmap(page);
+ write_page(page, 0);
+ }
+
+ return 0;
+}
+
+/*
+ * free memory that was allocated
+ */
+void bitmap_destroy(mddev_t *mddev)
+{
+ unsigned long k, pages;
+ struct bitmap_page *bp;
+ struct bitmap *bitmap = mddev->bitmap;
+
+ if (!bitmap) /* there was no bitmap */
+ return;
+
+ mddev->bitmap = NULL; /* disconnect from the md device */
+
+ /* release the bitmap file and kill the daemon */
+ bitmap_file_put(bitmap);
+
+ bp = bitmap->bp;
+ pages = bitmap->pages;
+
+ /* free all allocated memory */
+
+ mempool_destroy(bitmap->write_pool);
+
+ if (bp) /* deallocate the page memory */
+ for (k = 0; k < pages; k++)
+ if (bp[k].map && !bp[k].hijacked)
+ kfree(bp[k].map);
+ kfree(bp);
+ kfree(bitmap);
+}
+
+/*
+ * initialize the bitmap structure
+ * if this returns an error, bitmap_destroy must be called to do clean up
+ */
+int bitmap_create(mddev_t *mddev)
+{
+ struct bitmap *bitmap;
+ unsigned long blocks = mddev->resync_max_sectors;
+ unsigned long chunks;
+ unsigned long pages;
+ struct file *file = mddev->bitmap_file;
+ int err;
+
+ BUG_ON(sizeof(bitmap_super_t) != 256);
+
+ if (!file) /* bitmap disabled, nothing to do */
+ return 0;
+
+ bitmap = kmalloc(sizeof(*bitmap), GFP_KERNEL);
+ if (!bitmap)
+ return -ENOMEM;
+
+ memset(bitmap, 0, sizeof(*bitmap));
+
+ spin_lock_init(&bitmap->lock);
+ bitmap->mddev = mddev;
+ mddev->bitmap = bitmap;
+
+ spin_lock_init(&bitmap->write_lock);
+ init_MUTEX_LOCKED(&bitmap->write_done);
+ INIT_LIST_HEAD(&bitmap->complete_pages);
+ init_waitqueue_head(&bitmap->write_wait);
+ bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
+ write_pool_free, NULL);
+ if (!bitmap->write_pool)
+ return -ENOMEM;
+
+ bitmap->file = file;
+ get_file(file);
+ /* read superblock from bitmap file (this sets bitmap->chunksize) */
+ err = bitmap_read_sb(bitmap);
+ if (err)
+ return err;
+
+ bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
+ sizeof(bitmap->chunksize));
+
+ /* now that chunksize and chunkshift are set, we can use these macros */
+ chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
+ CHUNK_BLOCK_RATIO(bitmap);
+ pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
+
+ BUG_ON(!pages);
+
+ bitmap->chunks = chunks;
+ bitmap->pages = pages;
+ bitmap->missing_pages = pages;
+ bitmap->counter_bits = COUNTER_BITS;
+
+ bitmap->syncchunk = ~0UL;
+
+#if INJECT_FATAL_FAULT_1
+ bitmap->bp = NULL;
+#else
+ bitmap->bp = kmalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
+#endif
+ if (!bitmap->bp)
+ return -ENOMEM;
+ memset(bitmap->bp, 0, pages * sizeof(*bitmap->bp));
+
+ bitmap->flags |= BITMAP_ACTIVE;
+
+ /* now that we have some pages available, initialize the in-memory
+ * bitmap from the on-disk bitmap */
+ err = bitmap_init_from_disk(bitmap);
+ if (err)
+ return err;
+
+ printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
+ pages, bmname(bitmap));
+
+ /* kick off the bitmap daemons */
+ err = bitmap_start_daemons(bitmap);
+ if (err)
+ return err;
+ return bitmap_update_sb(bitmap);
+}
+
+/* the bitmap API -- for raid personalities */
+EXPORT_SYMBOL(bitmap_startwrite);
+EXPORT_SYMBOL(bitmap_endwrite);
+EXPORT_SYMBOL(bitmap_start_sync);
+EXPORT_SYMBOL(bitmap_end_sync);
+EXPORT_SYMBOL(bitmap_unplug);
+EXPORT_SYMBOL(bitmap_close_sync);
+EXPORT_SYMBOL(bitmap_daemon_work);
--- /dev/null
+/*
+ * bitmap.h: Copyright (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
+ *
+ * additions: Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
+ */
+#ifndef BITMAP_H
+#define BITMAP_H 1
+
+#define BITMAP_MAJOR 3
+#define BITMAP_MINOR 38
+
+/*
+ * in-memory bitmap:
+ *
+ * Use 16 bit block counters to track pending writes to each "chunk".
+ * The 2 high order bits are special-purpose, the first is a flag indicating
+ * whether a resync is needed. The second is a flag indicating whether a
+ * resync is active.
+ * This means that the counter is actually 14 bits:
+ *
+ * +--------+--------+------------------------------------------------+
+ * | resync | resync | counter |
+ * | needed | active | |
+ * | (0-1) | (0-1) | (0-16383) |
+ * +--------+--------+------------------------------------------------+
+ *
+ * The "resync needed" bit is set when:
+ * a '1' bit is read from storage at startup.
+ * a write request fails on some drives
+ * a resync is aborted on a chunk with 'resync active' set
+ * It is cleared (and resync-active set) when a resync starts across all drives
+ * of the chunk.
+ *
+ *
+ * The "resync active" bit is set when:
+ * a resync is started on all drives, and resync_needed is set.
+ * resync_needed will be cleared (as long as resync_active wasn't already set).
+ * It is cleared when a resync completes.
+ *
+ * The counter counts pending write requests, plus the on-disk bit.
+ * When the counter is '1' and the resync bits are clear, the on-disk
+ * bit can be cleared aswell, thus setting the counter to 0.
+ * When we set a bit, or in the counter (to start a write), if the fields is
+ * 0, we first set the disk bit and set the counter to 1.
+ *
+ * If the counter is 0, the on-disk bit is clear and the stipe is clean
+ * Anything that dirties the stipe pushes the counter to 2 (at least)
+ * and sets the on-disk bit (lazily).
+ * If a periodic sweep find the counter at 2, it is decremented to 1.
+ * If the sweep find the counter at 1, the on-disk bit is cleared and the
+ * counter goes to zero.
+ *
+ * Also, we'll hijack the "map" pointer itself and use it as two 16 bit block
+ * counters as a fallback when "page" memory cannot be allocated:
+ *
+ * Normal case (page memory allocated):
+ *
+ * page pointer (32-bit)
+ *
+ * [ ] ------+
+ * |
+ * +-------> [ ][ ]..[ ] (4096 byte page == 2048 counters)
+ * c1 c2 c2048
+ *
+ * Hijacked case (page memory allocation failed):
+ *
+ * hijacked page pointer (32-bit)
+ *
+ * [ ][ ] (no page memory allocated)
+ * counter #1 (16-bit) counter #2 (16-bit)
+ *
+ */
+
+#ifdef __KERNEL__
+
+#define PAGE_BITS (PAGE_SIZE << 3)
+#define PAGE_BIT_SHIFT (PAGE_SHIFT + 3)
+
+typedef __u16 bitmap_counter_t;
+#define COUNTER_BITS 16
+#define COUNTER_BIT_SHIFT 4
+#define COUNTER_BYTE_RATIO (COUNTER_BITS / 8)
+#define COUNTER_BYTE_SHIFT (COUNTER_BIT_SHIFT - 3)
+
+#define NEEDED_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 1)))
+#define RESYNC_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 2)))
+#define COUNTER_MAX ((bitmap_counter_t) RESYNC_MASK - 1)
+#define NEEDED(x) (((bitmap_counter_t) x) & NEEDED_MASK)
+#define RESYNC(x) (((bitmap_counter_t) x) & RESYNC_MASK)
+#define COUNTER(x) (((bitmap_counter_t) x) & COUNTER_MAX)
+
+/* how many counters per page? */
+#define PAGE_COUNTER_RATIO (PAGE_BITS / COUNTER_BITS)
+/* same, except a shift value for more efficient bitops */
+#define PAGE_COUNTER_SHIFT (PAGE_BIT_SHIFT - COUNTER_BIT_SHIFT)
+/* same, except a mask value for more efficient bitops */
+#define PAGE_COUNTER_MASK (PAGE_COUNTER_RATIO - 1)
+
+#define BITMAP_BLOCK_SIZE 512
+#define BITMAP_BLOCK_SHIFT 9
+
+/* how many blocks per chunk? (this is variable) */
+#define CHUNK_BLOCK_RATIO(bitmap) ((bitmap)->chunksize >> BITMAP_BLOCK_SHIFT)
+#define CHUNK_BLOCK_SHIFT(bitmap) ((bitmap)->chunkshift - BITMAP_BLOCK_SHIFT)
+#define CHUNK_BLOCK_MASK(bitmap) (CHUNK_BLOCK_RATIO(bitmap) - 1)
+
+/* when hijacked, the counters and bits represent even larger "chunks" */
+/* there will be 1024 chunks represented by each counter in the page pointers */
+#define PAGEPTR_BLOCK_RATIO(bitmap) \
+ (CHUNK_BLOCK_RATIO(bitmap) << PAGE_COUNTER_SHIFT >> 1)
+#define PAGEPTR_BLOCK_SHIFT(bitmap) \
+ (CHUNK_BLOCK_SHIFT(bitmap) + PAGE_COUNTER_SHIFT - 1)
+#define PAGEPTR_BLOCK_MASK(bitmap) (PAGEPTR_BLOCK_RATIO(bitmap) - 1)
+
+/*
+ * 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.
+ */
+
+/* map chunks (bits) to file pages - offset by the size of the superblock */
+#define CHUNK_BIT_OFFSET(chunk) ((chunk) + (sizeof(bitmap_super_t) << 3))
+
+#endif
+
+/*
+ * bitmap structures:
+ */
+
+#define BITMAP_MAGIC 0x6d746962
+
+/* use these for bitmap->flags and bitmap->sb->state bit-fields */
+enum bitmap_state {
+ BITMAP_ACTIVE = 0x001, /* the bitmap is in use */
+ BITMAP_STALE = 0x002 /* the bitmap file is out of date or had -EIO */
+};
+
+/* the superblock at the front of the bitmap file -- little endian */
+typedef struct bitmap_super_s {
+ __u32 magic; /* 0 BITMAP_MAGIC */
+ __u32 version; /* 4 the bitmap major for now, could change... */
+ __u8 uuid[16]; /* 8 128 bit uuid - must match md device uuid */
+ __u64 events; /* 24 event counter for the bitmap (1)*/
+ __u64 events_cleared;/*32 event counter when last bit cleared (2) */
+ __u64 sync_size; /* 40 the size of the md device's sync range(3) */
+ __u32 state; /* 48 bitmap state information */
+ __u32 chunksize; /* 52 the bitmap chunk size in bytes */
+ __u32 daemon_sleep; /* 56 seconds between disk flushes */
+
+ __u8 pad[256 - 60]; /* set to zero */
+} bitmap_super_t;
+
+/* notes:
+ * (1) This event counter is updated before the eventcounter in the md superblock
+ * When a bitmap is loaded, it is only accepted if this event counter is equal
+ * to, or one greater than, the event counter in the superblock.
+ * (2) This event counter is updated when the other one is *if*and*only*if* the
+ * array is not degraded. As bits are not cleared when the array is degraded,
+ * this represents the last time that any bits were cleared.
+ * If a device is being added that has an event count with this value or
+ * higher, it is accepted as conforming to the bitmap.
+ * (3)This is the number of sectors represented by the bitmap, and is the range that
+ * resync happens across. For raid1 and raid5/6 it is the size of individual
+ * devices. For raid10 it is the size of the array.
+ */
+
+#ifdef __KERNEL__
+
+/* the in-memory bitmap is represented by bitmap_pages */
+struct bitmap_page {
+ /*
+ * map points to the actual memory page
+ */
+ char *map;
+ /*
+ * in emergencies (when map cannot be alloced), hijack the map
+ * pointer and use it as two counters itself
+ */
+ unsigned int hijacked:1;
+ /*
+ * count of dirty bits on the page
+ */
+ unsigned int count:31;
+};
+
+/* keep track of bitmap file pages that have pending writes on them */
+struct page_list {
+ struct list_head list;
+ struct page *page;
+};
+
+/* the main bitmap structure - one per mddev */
+struct bitmap {
+ struct bitmap_page *bp;
+ unsigned long pages; /* total number of pages in the bitmap */
+ unsigned long missing_pages; /* number of pages not yet allocated */
+
+ mddev_t *mddev; /* the md device that the bitmap is for */
+
+ int counter_bits; /* how many bits per block counter */
+
+ /* bitmap chunksize -- how much data does each bit represent? */
+ unsigned long chunksize;
+ unsigned long chunkshift; /* chunksize = 2^chunkshift (for bitops) */
+ unsigned long chunks; /* total number of data chunks for the array */
+
+ /* We hold a count on the chunk currently being synced, and drop
+ * it when the last block is started. If the resync is aborted
+ * midway, we need to be able to drop that count, so we remember
+ * the counted chunk..
+ */
+ unsigned long syncchunk;
+
+ __u64 events_cleared;
+
+ /* bitmap spinlock */
+ spinlock_t lock;
+
+ struct file *file; /* backing disk file */
+ struct page *sb_page; /* cached copy of the bitmap file superblock */
+ struct page **filemap; /* list of cache pages for the file */
+ unsigned long *filemap_attr; /* attributes associated w/ filemap pages */
+ unsigned long file_pages; /* number of pages in the file */
+
+ unsigned long flags;
+
+ /*
+ * the bitmap daemon - periodically wakes up and sweeps the bitmap
+ * file, cleaning up bits and flushing out pages to disk as necessary
+ */
+ unsigned long daemon_lastrun; /* jiffies of last run */
+ unsigned long daemon_sleep; /* how many seconds between updates? */
+
+ /*
+ * bitmap write daemon - this daemon performs writes to the bitmap file
+ * this thread is only needed because of a limitation in ext3 (jbd)
+ * that does not allow a task to have two journal transactions ongoing
+ * simultaneously (even if the transactions are for two different
+ * filesystems) -- in the case of bitmap, that would be the filesystem
+ * that the bitmap file resides on and the filesystem that is mounted
+ * on the md device -- see current->journal_info in jbd/transaction.c
+ */
+ mdk_thread_t *writeback_daemon;
+ spinlock_t write_lock;
+ struct semaphore write_ready;
+ struct semaphore write_done;
+ unsigned long writes_pending;
+ wait_queue_head_t write_wait;
+ struct list_head write_pages;
+ struct list_head complete_pages;
+ mempool_t *write_pool;
+};
+
+/* the bitmap API */
+
+/* these are used only by md/bitmap */
+int bitmap_create(mddev_t *mddev);
+void bitmap_destroy(mddev_t *mddev);
+int bitmap_active(struct bitmap *bitmap);
+
+char *file_path(struct file *file, char *buf, int count);
+void bitmap_print_sb(struct bitmap *bitmap);
+int bitmap_update_sb(struct bitmap *bitmap);
+
+int bitmap_setallbits(struct bitmap *bitmap);
+
+/* these are exported */
+int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors);
+void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
+ int success);
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks);
+void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted);
+void bitmap_close_sync(struct bitmap *bitmap);
+
+int bitmap_unplug(struct bitmap *bitmap);
+int bitmap_daemon_work(struct bitmap *bitmap);
+#endif
+
+#endif
projects / linux-2.6 / commitdiff