SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/md/bitmap.c

   1 /*
   2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   3  *
   4  * bitmap_create  - sets up the bitmap structure
   5  * bitmap_destroy - destroys the bitmap structure
   6  *
   7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   8  * - added disk storage for bitmap
   9  * - changes to allow various bitmap chunk sizes
  10  */
  11
  12 /*
  13  * Still to do:
  14  *
  15  * flush after percent set rather than just time based. (maybe both).
  16  * wait if count gets too high, wake when it drops to half.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/errno.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/timer.h>
  25 #include <linux/sched.h>
  26 #include <linux/list.h>
  27 #include <linux/file.h>
  28 #include <linux/mount.h>
  29 #include <linux/buffer_head.h>
  30 #include "md.h"
  31 #include "bitmap.h"
  32
  33 /* debug macros */
  34
  35 #define DEBUG 0
  36
  37 #if DEBUG
  38 /* these are for debugging purposes only! */
  39
  40 /* define one and only one of these */
  41 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
  42 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
  43 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
  44 #define INJECT_FAULTS_4 0 /* undef */
  45 #define INJECT_FAULTS_5 0 /* undef */
  46 #define INJECT_FAULTS_6 0
  47
  48 /* if these are defined, the driver will fail! debug only */
  49 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
  50 #define INJECT_FATAL_FAULT_2 0 /* undef */
  51 #define INJECT_FATAL_FAULT_3 0 /* undef */
  52 #endif
  53
  54 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
  55 #define DPRINTK(x...) do { } while(0)
  56
  57 #ifndef PRINTK
  58 #  if DEBUG > 0
  59 #    define PRINTK(x...) printk(KERN_DEBUG x)
  60 #  else
  61 #    define PRINTK(x...)
  62 #  endif
  63 #endif
  64
  65 static inline char * bmname(struct bitmap *bitmap)
  66 {
  67         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  68 }
  69
  70
  71 /*
  72  * just a placeholder - calls kmalloc for bitmap pages
  73  */
  74 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
  75 {
  76         unsigned char *page;
  77
  78 #ifdef INJECT_FAULTS_1
  79         page = NULL;
  80 #else
  81         page = kmalloc(PAGE_SIZE, GFP_NOIO);
  82 #endif
  83         if (!page)
  84                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
  85         else
  86                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
  87                         bmname(bitmap), page);
  88         return page;
  89 }
  90
  91 /*
  92  * for now just a placeholder -- just calls kfree for bitmap pages
  93  */
  94 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
  95 {
  96         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
  97         kfree(page);
  98 }
  99
 100 /*
 101  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
 102  *
 103  * 1) check to see if this page is allocated, if it's not then try to alloc
 104  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
 105  *    page pointer directly as a counter
 106  *
 107  * if we find our page, we increment the page's refcount so that it stays
 108  * allocated while we're using it
 109  */
 110 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
 111 __releases(bitmap->lock)
 112 __acquires(bitmap->lock)
 113 {
 114         unsigned char *mappage;
 115
 116         if (page >= bitmap->pages) {
 117                 /* This can happen if bitmap_start_sync goes beyond
 118                  * End-of-device while looking for a whole page.
 119                  * It is harmless.
 120                  */
 121                 return -EINVAL;
 122         }
 123
 124
 125         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 126                 return 0;
 127
 128         if (bitmap->bp[page].map) /* page is already allocated, just return */
 129                 return 0;
 130
 131         if (!create)
 132                 return -ENOENT;
 133
 134         spin_unlock_irq(&bitmap->lock);
 135
 136         /* this page has not been allocated yet */
 137
 138         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
 139                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
 140                         bmname(bitmap));
 141                 /* failed - set the hijacked flag so that we can use the
 142                  * pointer as a counter */
 143                 spin_lock_irq(&bitmap->lock);
 144                 if (!bitmap->bp[page].map)
 145                         bitmap->bp[page].hijacked = 1;
 146                 goto out;
 147         }
 148
 149         /* got a page */
 150
 151         spin_lock_irq(&bitmap->lock);
 152
 153         /* recheck the page */
 154
 155         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
 156                 /* somebody beat us to getting the page */
 157                 bitmap_free_page(bitmap, mappage);
 158                 return 0;
 159         }
 160
 161         /* no page was in place and we have one, so install it */
 162
 163         memset(mappage, 0, PAGE_SIZE);
 164         bitmap->bp[page].map = mappage;
 165         bitmap->missing_pages--;
 166 out:
 167         return 0;
 168 }
 169
 170
 171 /* if page is completely empty, put it back on the free list, or dealloc it */
 172 /* if page was hijacked, unmark the flag so it might get alloced next time */
 173 /* Note: lock should be held when calling this */
 174 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
 175 {
 176         char *ptr;
 177
 178         if (bitmap->bp[page].count) /* page is still busy */
 179                 return;
 180
 181         /* page is no longer in use, it can be released */
 182
 183         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 184                 bitmap->bp[page].hijacked = 0;
 185                 bitmap->bp[page].map = NULL;
 186                 return;
 187         }
 188
 189         /* normal case, free the page */
 190
 191 #if 0
 192 /* actually ... let's not.  We will probably need the page again exactly when
 193  * memory is tight and we are flusing to disk
 194  */
 195         return;
 196 #else
 197         ptr = bitmap->bp[page].map;
 198         bitmap->bp[page].map = NULL;
 199         bitmap->missing_pages++;
 200         bitmap_free_page(bitmap, ptr);
 201         return;
 202 #endif
 203 }
 204
 205
 206 /*
 207  * bitmap file handling - read and write the bitmap file and its superblock
 208  */
 209
 210 /*
 211  * basic page I/O operations
 212  */
 213
 214 /* IO operations when bitmap is stored near all superblocks */
 215 static struct page *read_sb_page(mddev_t *mddev, loff_t offset,
 216                                  struct page *page,
 217                                  unsigned long index, int size)
 218 {
 219         /* choose a good rdev and read the page from there */
 220
 221         mdk_rdev_t *rdev;
 222         sector_t target;
 223
 224         if (!page)
 225                 page = alloc_page(GFP_KERNEL);
 226         if (!page)
 227                 return ERR_PTR(-ENOMEM);
 228
 229         list_for_each_entry(rdev, &mddev->disks, same_set) {
 230                 if (! test_bit(In_sync, &rdev->flags)
 231                     || test_bit(Faulty, &rdev->flags))
 232                         continue;
 233
 234                 target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 235
 236                 if (sync_page_io(rdev->bdev, target,
 237                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 238                                  page, READ)) {
 239                         page->index = index;
 240                         attach_page_buffers(page, NULL); /* so that free_buffer will
 241                                                           * quietly no-op */
 242                         return page;
 243                 }
 244         }
 245         return ERR_PTR(-EIO);
 246
 247 }
 248
 249 static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 250 {
 251         /* Iterate the disks of an mddev, using rcu to protect access to the
 252          * linked list, and raising the refcount of devices we return to ensure
 253          * they don't disappear while in use.
 254          * As devices are only added or removed when raid_disk is < 0 and
 255          * nr_pending is 0 and In_sync is clear, the entries we return will
 256          * still be in the same position on the list when we re-enter
 257          * list_for_each_continue_rcu.
 258          */
 259         struct list_head *pos;
 260         rcu_read_lock();
 261         if (rdev == NULL)
 262                 /* start at the beginning */
 263                 pos = &mddev->disks;
 264         else {
 265                 /* release the previous rdev and start from there. */
 266                 rdev_dec_pending(rdev, mddev);
 267                 pos = &rdev->same_set;
 268         }
 269         list_for_each_continue_rcu(pos, &mddev->disks) {
 270                 rdev = list_entry(pos, mdk_rdev_t, same_set);
 271                 if (rdev->raid_disk >= 0 &&
 272                     !test_bit(Faulty, &rdev->flags)) {
 273                         /* this is a usable devices */
 274                         atomic_inc(&rdev->nr_pending);
 275                         rcu_read_unlock();
 276                         return rdev;
 277                 }
 278         }
 279         rcu_read_unlock();
 280         return NULL;
 281 }
 282
 283 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 284 {
 285         mdk_rdev_t *rdev = NULL;
 286         mddev_t *mddev = bitmap->mddev;
 287
 288         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 289                         int size = PAGE_SIZE;
 290                         loff_t offset = mddev->bitmap_info.offset;
 291                         if (page->index == bitmap->file_pages-1)
 292                                 size = roundup(bitmap->last_page_size,
 293                                                bdev_logical_block_size(rdev->bdev));
 294                         /* Just make sure we aren't corrupting data or
 295                          * metadata
 296                          */
 297                         if (mddev->external) {
 298                                 /* Bitmap could be anywhere. */
 299                                 if (rdev->sb_start + offset + (page->index *(PAGE_SIZE/512)) >
 300                                     rdev->data_offset &&
 301                                     rdev->sb_start + offset <
 302                                     rdev->data_offset + mddev->dev_sectors +
 303                                     (PAGE_SIZE/512))
 304                                         goto bad_alignment;
 305                         } else if (offset < 0) {
 306                                 /* DATA  BITMAP METADATA  */
 307                                 if (offset
 308                                     + (long)(page->index * (PAGE_SIZE/512))
 309                                     + size/512 > 0)
 310                                         /* bitmap runs in to metadata */
 311                                         goto bad_alignment;
 312                                 if (rdev->data_offset + mddev->dev_sectors
 313                                     > rdev->sb_start + offset)
 314                                         /* data runs in to bitmap */
 315                                         goto bad_alignment;
 316                         } else if (rdev->sb_start < rdev->data_offset) {
 317                                 /* METADATA BITMAP DATA */
 318                                 if (rdev->sb_start
 319                                     + offset
 320                                     + page->index*(PAGE_SIZE/512) + size/512
 321                                     > rdev->data_offset)
 322                                         /* bitmap runs in to data */
 323                                         goto bad_alignment;
 324                         } else {
 325                                 /* DATA METADATA BITMAP - no problems */
 326                         }
 327                         md_super_write(mddev, rdev,
 328                                        rdev->sb_start + offset
 329                                        + page->index * (PAGE_SIZE/512),
 330                                        size,
 331                                        page);
 332         }
 333
 334         if (wait)
 335                 md_super_wait(mddev);
 336         return 0;
 337
 338  bad_alignment:
 339         return -EINVAL;
 340 }
 341
 342 static void bitmap_file_kick(struct bitmap *bitmap);
 343 /*
 344  * write out a page to a file
 345  */
 346 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 347 {
 348         struct buffer_head *bh;
 349
 350         if (bitmap->file == NULL) {
 351                 switch (write_sb_page(bitmap, page, wait)) {
 352                 case -EINVAL:
 353                         bitmap->flags |= BITMAP_WRITE_ERROR;
 354                 }
 355         } else {
 356
 357                 bh = page_buffers(page);
 358
 359                 while (bh && bh->b_blocknr) {
 360                         atomic_inc(&bitmap->pending_writes);
 361                         set_buffer_locked(bh);
 362                         set_buffer_mapped(bh);
 363                         submit_bh(WRITE, bh);
 364                         bh = bh->b_this_page;
 365                 }
 366
 367                 if (wait) {
 368                         wait_event(bitmap->write_wait,
 369                                    atomic_read(&bitmap->pending_writes)==0);
 370                 }
 371         }
 372         if (bitmap->flags & BITMAP_WRITE_ERROR)
 373                 bitmap_file_kick(bitmap);
 374 }
 375
 376 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 377 {
 378         struct bitmap *bitmap = bh->b_private;
 379         unsigned long flags;
 380
 381         if (!uptodate) {
 382                 spin_lock_irqsave(&bitmap->lock, flags);
 383                 bitmap->flags |= BITMAP_WRITE_ERROR;
 384                 spin_unlock_irqrestore(&bitmap->lock, flags);
 385         }
 386         if (atomic_dec_and_test(&bitmap->pending_writes))
 387                 wake_up(&bitmap->write_wait);
 388 }
 389
 390 /* copied from buffer.c */
 391 static void
 392 __clear_page_buffers(struct page *page)
 393 {
 394         ClearPagePrivate(page);
 395         set_page_private(page, 0);
 396         page_cache_release(page);
 397 }
 398 static void free_buffers(struct page *page)
 399 {
 400         struct buffer_head *bh = page_buffers(page);
 401
 402         while (bh) {
 403                 struct buffer_head *next = bh->b_this_page;
 404                 free_buffer_head(bh);
 405                 bh = next;
 406         }
 407         __clear_page_buffers(page);
 408         put_page(page);
 409 }
 410
 411 /* read a page from a file.
 412  * We both read the page, and attach buffers to the page to record the
 413  * address of each block (using bmap).  These addresses will be used
 414  * to write the block later, completely bypassing the filesystem.
 415  * This usage is similar to how swap files are handled, and allows us
 416  * to write to a file with no concerns of memory allocation failing.
 417  */
 418 static struct page *read_page(struct file *file, unsigned long index,
 419                               struct bitmap *bitmap,
 420                               unsigned long count)
 421 {
 422         struct page *page = NULL;
 423         struct inode *inode = file->f_path.dentry->d_inode;
 424         struct buffer_head *bh;
 425         sector_t block;
 426
 427         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
 428                         (unsigned long long)index << PAGE_SHIFT);
 429
 430         page = alloc_page(GFP_KERNEL);
 431         if (!page)
 432                 page = ERR_PTR(-ENOMEM);
 433         if (IS_ERR(page))
 434                 goto out;
 435
 436         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 437         if (!bh) {
 438                 put_page(page);
 439                 page = ERR_PTR(-ENOMEM);
 440                 goto out;
 441         }
 442         attach_page_buffers(page, bh);
 443         block = index << (PAGE_SHIFT - inode->i_blkbits);
 444         while (bh) {
 445                 if (count == 0)
 446                         bh->b_blocknr = 0;
 447                 else {
 448                         bh->b_blocknr = bmap(inode, block);
 449                         if (bh->b_blocknr == 0) {
 450                                 /* Cannot use this file! */
 451                                 free_buffers(page);
 452                                 page = ERR_PTR(-EINVAL);
 453                                 goto out;
 454                         }
 455                         bh->b_bdev = inode->i_sb->s_bdev;
 456                         if (count < (1<<inode->i_blkbits))
 457                                 count = 0;
 458                         else
 459                                 count -= (1<<inode->i_blkbits);
 460
 461                         bh->b_end_io = end_bitmap_write;
 462                         bh->b_private = bitmap;
 463                         atomic_inc(&bitmap->pending_writes);
 464                         set_buffer_locked(bh);
 465                         set_buffer_mapped(bh);
 466                         submit_bh(READ, bh);
 467                 }
 468                 block++;
 469                 bh = bh->b_this_page;
 470         }
 471         page->index = index;
 472
 473         wait_event(bitmap->write_wait,
 474                    atomic_read(&bitmap->pending_writes)==0);
 475         if (bitmap->flags & BITMAP_WRITE_ERROR) {
 476                 free_buffers(page);
 477                 page = ERR_PTR(-EIO);
 478         }
 479 out:
 480         if (IS_ERR(page))
 481                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
 482                         (int)PAGE_SIZE,
 483                         (unsigned long long)index << PAGE_SHIFT,
 484                         PTR_ERR(page));
 485         return page;
 486 }
 487
 488 /*
 489  * bitmap file superblock operations
 490  */
 491
 492 /* update the event counter and sync the superblock to disk */
 493 void bitmap_update_sb(struct bitmap *bitmap)
 494 {
 495         bitmap_super_t *sb;
 496         unsigned long flags;
 497
 498         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 499                 return;
 500         spin_lock_irqsave(&bitmap->lock, flags);
 501         if (!bitmap->sb_page) { /* no superblock */
 502                 spin_unlock_irqrestore(&bitmap->lock, flags);
 503                 return;
 504         }
 505         spin_unlock_irqrestore(&bitmap->lock, flags);
 506         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 507         sb->events = cpu_to_le64(bitmap->mddev->events);
 508         if (bitmap->mddev->events < bitmap->events_cleared) {
 509                 /* rocking back to read-only */
 510                 bitmap->events_cleared = bitmap->mddev->events;
 511                 sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 512         }
 513         kunmap_atomic(sb, KM_USER0);
 514         write_page(bitmap, bitmap->sb_page, 1);
 515 }
 516
 517 /* print out the bitmap file superblock */
 518 void bitmap_print_sb(struct bitmap *bitmap)
 519 {
 520         bitmap_super_t *sb;
 521
 522         if (!bitmap || !bitmap->sb_page)
 523                 return;
 524         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 525         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 526         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 527         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 528         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 529                                         *(__u32 *)(sb->uuid+0),
 530                                         *(__u32 *)(sb->uuid+4),
 531                                         *(__u32 *)(sb->uuid+8),
 532                                         *(__u32 *)(sb->uuid+12));
 533         printk(KERN_DEBUG "        events: %llu\n",
 534                         (unsigned long long) le64_to_cpu(sb->events));
 535         printk(KERN_DEBUG "events cleared: %llu\n",
 536                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 537         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 538         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 539         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 540         printk(KERN_DEBUG "     sync size: %llu KB\n",
 541                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 542         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 543         kunmap_atomic(sb, KM_USER0);
 544 }
 545
 546 /* read the superblock from the bitmap file and initialize some bitmap fields */
 547 static int bitmap_read_sb(struct bitmap *bitmap)
 548 {
 549         char *reason = NULL;
 550         bitmap_super_t *sb;
 551         unsigned long chunksize, daemon_sleep, write_behind;
 552         unsigned long long events;
 553         int err = -EINVAL;
 554
 555         /* page 0 is the superblock, read it... */
 556         if (bitmap->file) {
 557                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
 558                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 559
 560                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
 561         } else {
 562                 bitmap->sb_page = read_sb_page(bitmap->mddev,
 563                                                bitmap->mddev->bitmap_info.offset,
 564                                                NULL,
 565                                                0, sizeof(bitmap_super_t));
 566         }
 567         if (IS_ERR(bitmap->sb_page)) {
 568                 err = PTR_ERR(bitmap->sb_page);
 569                 bitmap->sb_page = NULL;
 570                 return err;
 571         }
 572
 573         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 574
 575         chunksize = le32_to_cpu(sb->chunksize);
 576         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 577         write_behind = le32_to_cpu(sb->write_behind);
 578
 579         /* verify that the bitmap-specific fields are valid */
 580         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 581                 reason = "bad magic";
 582         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 583                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 584                 reason = "unrecognized superblock version";
 585         else if (chunksize < 512)
 586                 reason = "bitmap chunksize too small";
 587         else if ((1 << ffz(~chunksize)) != chunksize)
 588                 reason = "bitmap chunksize not a power of 2";
 589         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 590                 reason = "daemon sleep period out of range";
 591         else if (write_behind > COUNTER_MAX)
 592                 reason = "write-behind limit out of range (0 - 16383)";
 593         if (reason) {
 594                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 595                         bmname(bitmap), reason);
 596                 goto out;
 597         }
 598
 599         /* keep the array size field of the bitmap superblock up to date */
 600         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 601
 602         if (!bitmap->mddev->persistent)
 603                 goto success;
 604
 605         /*
 606          * if we have a persistent array superblock, compare the
 607          * bitmap's UUID and event counter to the mddev's
 608          */
 609         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 610                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
 611                         bmname(bitmap));
 612                 goto out;
 613         }
 614         events = le64_to_cpu(sb->events);
 615         if (events < bitmap->mddev->events) {
 616                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
 617                         "-- forcing full recovery\n", bmname(bitmap), events,
 618                         (unsigned long long) bitmap->mddev->events);
 619                 sb->state |= cpu_to_le32(BITMAP_STALE);
 620         }
 621 success:
 622         /* assign fields using values from superblock */
 623         bitmap->mddev->bitmap_info.chunksize = chunksize;
 624         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 625         bitmap->daemon_lastrun = jiffies;
 626         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 627         bitmap->flags |= le32_to_cpu(sb->state);
 628         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 629                 bitmap->flags |= BITMAP_HOSTENDIAN;
 630         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 631         if (sb->state & cpu_to_le32(BITMAP_STALE))
 632                 bitmap->events_cleared = bitmap->mddev->events;
 633         err = 0;
 634 out:
 635         kunmap_atomic(sb, KM_USER0);
 636         if (err)
 637                 bitmap_print_sb(bitmap);
 638         return err;
 639 }
 640
 641 enum bitmap_mask_op {
 642         MASK_SET,
 643         MASK_UNSET
 644 };
 645
 646 /* record the state of the bitmap in the superblock.  Return the old value */
 647 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
 648                              enum bitmap_mask_op op)
 649 {
 650         bitmap_super_t *sb;
 651         unsigned long flags;
 652         int old;
 653
 654         spin_lock_irqsave(&bitmap->lock, flags);
 655         if (!bitmap->sb_page) { /* can't set the state */
 656                 spin_unlock_irqrestore(&bitmap->lock, flags);
 657                 return 0;
 658         }
 659         spin_unlock_irqrestore(&bitmap->lock, flags);
 660         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 661         old = le32_to_cpu(sb->state) & bits;
 662         switch (op) {
 663                 case MASK_SET: sb->state |= cpu_to_le32(bits);
 664                                 break;
 665                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
 666                                 break;
 667                 default: BUG();
 668         }
 669         kunmap_atomic(sb, KM_USER0);
 670         return old;
 671 }
 672
 673 /*
 674  * general bitmap file operations
 675  */
 676
 677 /* calculate the index of the page that contains this bit */
 678 static inline unsigned long file_page_index(unsigned long chunk)
 679 {
 680         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
 681 }
 682
 683 /* calculate the (bit) offset of this bit within a page */
 684 static inline unsigned long file_page_offset(unsigned long chunk)
 685 {
 686         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
 687 }
 688
 689 /*
 690  * return a pointer to the page in the filemap that contains the given bit
 691  *
 692  * this lookup is complicated by the fact that the bitmap sb might be exactly
 693  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 694  * 0 or page 1
 695  */
 696 static inline struct page *filemap_get_page(struct bitmap *bitmap,
 697                                         unsigned long chunk)
 698 {
 699         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
 700         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
 701 }
 702
 703
 704 static void bitmap_file_unmap(struct bitmap *bitmap)
 705 {
 706         struct page **map, *sb_page;
 707         unsigned long *attr;
 708         int pages;
 709         unsigned long flags;
 710
 711         spin_lock_irqsave(&bitmap->lock, flags);
 712         map = bitmap->filemap;
 713         bitmap->filemap = NULL;
 714         attr = bitmap->filemap_attr;
 715         bitmap->filemap_attr = NULL;
 716         pages = bitmap->file_pages;
 717         bitmap->file_pages = 0;
 718         sb_page = bitmap->sb_page;
 719         bitmap->sb_page = NULL;
 720         spin_unlock_irqrestore(&bitmap->lock, flags);
 721
 722         while (pages--)
 723                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
 724                         free_buffers(map[pages]);
 725         kfree(map);
 726         kfree(attr);
 727
 728         if (sb_page)
 729                 free_buffers(sb_page);
 730 }
 731
 732 static void bitmap_file_put(struct bitmap *bitmap)
 733 {
 734         struct file *file;
 735         unsigned long flags;
 736
 737         spin_lock_irqsave(&bitmap->lock, flags);
 738         file = bitmap->file;
 739         bitmap->file = NULL;
 740         spin_unlock_irqrestore(&bitmap->lock, flags);
 741
 742         if (file)
 743                 wait_event(bitmap->write_wait,
 744                            atomic_read(&bitmap->pending_writes)==0);
 745         bitmap_file_unmap(bitmap);
 746
 747         if (file) {
 748                 struct inode *inode = file->f_path.dentry->d_inode;
 749                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 750                 fput(file);
 751         }
 752 }
 753
 754
 755 /*
 756  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 757  * then it is no longer reliable, so we stop using it and we mark the file
 758  * as failed in the superblock
 759  */
 760 static void bitmap_file_kick(struct bitmap *bitmap)
 761 {
 762         char *path, *ptr = NULL;
 763
 764         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
 765                 bitmap_update_sb(bitmap);
 766
 767                 if (bitmap->file) {
 768                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 769                         if (path)
 770                                 ptr = d_path(&bitmap->file->f_path, path,
 771                                              PAGE_SIZE);
 772
 773
 774                         printk(KERN_ALERT
 775                               "%s: kicking failed bitmap file %s from array!\n",
 776                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 777
 778                         kfree(path);
 779                 } else
 780                         printk(KERN_ALERT
 781                                "%s: disabling internal bitmap due to errors\n",
 782                                bmname(bitmap));
 783         }
 784
 785         bitmap_file_put(bitmap);
 786
 787         return;
 788 }
 789
 790 enum bitmap_page_attr {
 791         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
 792         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
 793         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
 794 };
 795
 796 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
 797                                 enum bitmap_page_attr attr)
 798 {
 799         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
 800 }
 801
 802 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
 803                                 enum bitmap_page_attr attr)
 804 {
 805         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
 806 }
 807
 808 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
 809                                            enum bitmap_page_attr attr)
 810 {
 811         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
 812 }
 813
 814 /*
 815  * bitmap_file_set_bit -- called before performing a write to the md device
 816  * to set (and eventually sync) a particular bit in the bitmap file
 817  *
 818  * we set the bit immediately, then we record the page number so that
 819  * when an unplug occurs, we can flush the dirty pages out to disk
 820  */
 821 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 822 {
 823         unsigned long bit;
 824         struct page *page;
 825         void *kaddr;
 826         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
 827
 828         if (!bitmap->filemap) {
 829                 return;
 830         }
 831
 832         page = filemap_get_page(bitmap, chunk);
 833         if (!page) return;
 834         bit = file_page_offset(chunk);
 835
 836         /* set the bit */
 837         kaddr = kmap_atomic(page, KM_USER0);
 838         if (bitmap->flags & BITMAP_HOSTENDIAN)
 839                 set_bit(bit, kaddr);
 840         else
 841                 ext2_set_bit(bit, kaddr);
 842         kunmap_atomic(kaddr, KM_USER0);
 843         PRINTK("set file bit %lu page %lu\n", bit, page->index);
 844
 845         /* record page number so it gets flushed to disk when unplug occurs */
 846         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 847
 848 }
 849
 850 /* this gets called when the md device is ready to unplug its underlying
 851  * (slave) device queues -- before we let any writes go down, we need to
 852  * sync the dirty pages of the bitmap file to disk */
 853 void bitmap_unplug(struct bitmap *bitmap)
 854 {
 855         unsigned long i, flags;
 856         int dirty, need_write;
 857         struct page *page;
 858         int wait = 0;
 859
 860         if (!bitmap)
 861                 return;
 862
 863         /* look at each page to see if there are any set bits that need to be
 864          * flushed out to disk */
 865         for (i = 0; i < bitmap->file_pages; i++) {
 866                 spin_lock_irqsave(&bitmap->lock, flags);
 867                 if (!bitmap->filemap) {
 868                         spin_unlock_irqrestore(&bitmap->lock, flags);
 869                         return;
 870                 }
 871                 page = bitmap->filemap[i];
 872                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 873                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 874                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
 875                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 876                 if (dirty)
 877                         wait = 1;
 878                 spin_unlock_irqrestore(&bitmap->lock, flags);
 879
 880                 if (dirty | need_write)
 881                         write_page(bitmap, page, 0);
 882         }
 883         if (wait) { /* if any writes were performed, we need to wait on them */
 884                 if (bitmap->file)
 885                         wait_event(bitmap->write_wait,
 886                                    atomic_read(&bitmap->pending_writes)==0);
 887                 else
 888                         md_super_wait(bitmap->mddev);
 889         }
 890         if (bitmap->flags & BITMAP_WRITE_ERROR)
 891                 bitmap_file_kick(bitmap);
 892 }
 893
 894 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 895 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 896  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 897  * memory mapping of the bitmap file
 898  * Special cases:
 899  *   if there's no bitmap file, or if the bitmap file had been
 900  *   previously kicked from the array, we mark all the bits as
 901  *   1's in order to cause a full resync.
 902  *
 903  * We ignore all bits for sectors that end earlier than 'start'.
 904  * This is used when reading an out-of-date bitmap...
 905  */
 906 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 907 {
 908         unsigned long i, chunks, index, oldindex, bit;
 909         struct page *page = NULL, *oldpage = NULL;
 910         unsigned long num_pages, bit_cnt = 0;
 911         struct file *file;
 912         unsigned long bytes, offset;
 913         int outofdate;
 914         int ret = -ENOSPC;
 915         void *paddr;
 916
 917         chunks = bitmap->chunks;
 918         file = bitmap->file;
 919
 920         BUG_ON(!file && !bitmap->mddev->bitmap_info.offset);
 921
 922 #ifdef INJECT_FAULTS_3
 923         outofdate = 1;
 924 #else
 925         outofdate = bitmap->flags & BITMAP_STALE;
 926 #endif
 927         if (outofdate)
 928                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 929                         "recovery\n", bmname(bitmap));
 930
 931         bytes = (chunks + 7) / 8;
 932
 933         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
 934
 935         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
 936                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 937                         bmname(bitmap),
 938                         (unsigned long) i_size_read(file->f_mapping->host),
 939                         bytes + sizeof(bitmap_super_t));
 940                 goto err;
 941         }
 942
 943         ret = -ENOMEM;
 944
 945         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
 946         if (!bitmap->filemap)
 947                 goto err;
 948
 949         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 950         bitmap->filemap_attr = kzalloc(
 951                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 952                 GFP_KERNEL);
 953         if (!bitmap->filemap_attr)
 954                 goto err;
 955
 956         oldindex = ~0L;
 957
 958         for (i = 0; i < chunks; i++) {
 959                 int b;
 960                 index = file_page_index(i);
 961                 bit = file_page_offset(i);
 962                 if (index != oldindex) { /* this is a new page, read it in */
 963                         int count;
 964                         /* unmap the old page, we're done with it */
 965                         if (index == num_pages-1)
 966                                 count = bytes + sizeof(bitmap_super_t)
 967                                         - index * PAGE_SIZE;
 968                         else
 969                                 count = PAGE_SIZE;
 970                         if (index == 0) {
 971                                 /*
 972                                  * if we're here then the superblock page
 973                                  * contains some bits (PAGE_SIZE != sizeof sb)
 974                                  * we've already read it in, so just use it
 975                                  */
 976                                 page = bitmap->sb_page;
 977                                 offset = sizeof(bitmap_super_t);
 978                                 if (!file)
 979                                         read_sb_page(bitmap->mddev,
 980                                                      bitmap->mddev->bitmap_info.offset,
 981                                                      page,
 982                                                      index, count);
 983                         } else if (file) {
 984                                 page = read_page(file, index, bitmap, count);
 985                                 offset = 0;
 986                         } else {
 987                                 page = read_sb_page(bitmap->mddev,
 988                                                     bitmap->mddev->bitmap_info.offset,
 989                                                     NULL,
 990                                                     index, count);
 991                                 offset = 0;
 992                         }
 993                         if (IS_ERR(page)) { /* read error */
 994                                 ret = PTR_ERR(page);
 995                                 goto err;
 996                         }
 997
 998                         oldindex = index;
 999                         oldpage = page;
1000
1001                         bitmap->filemap[bitmap->file_pages++] = page;
1002                         bitmap->last_page_size = count;
1003
1004                         if (outofdate) {
1005                                 /*
1006                                  * if bitmap is out of date, dirty the
1007                                  * whole page and write it out
1008                                  */
1009                                 paddr = kmap_atomic(page, KM_USER0);
1010                                 memset(paddr + offset, 0xff,
1011                                        PAGE_SIZE - offset);
1012                                 kunmap_atomic(paddr, KM_USER0);
1013                                 write_page(bitmap, page, 1);
1014
1015                                 ret = -EIO;
1016                                 if (bitmap->flags & BITMAP_WRITE_ERROR)
1017                                         goto err;
1018                         }
1019                 }
1020                 paddr = kmap_atomic(page, KM_USER0);
1021                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1022                         b = test_bit(bit, paddr);
1023                 else
1024                         b = ext2_test_bit(bit, paddr);
1025                 kunmap_atomic(paddr, KM_USER0);
1026                 if (b) {
1027                         /* if the disk bit is set, set the memory bit */
1028                         int needed = ((sector_t)(i+1) << (CHUNK_BLOCK_SHIFT(bitmap))
1029                                       >= start);
1030                         bitmap_set_memory_bits(bitmap,
1031                                                (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),
1032                                                needed);
1033                         bit_cnt++;
1034                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1035                 }
1036         }
1037
1038         /* everything went OK */
1039         ret = 0;
1040         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
1041
1042         if (bit_cnt) { /* Kick recovery if any bits were set */
1043                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1044                 md_wakeup_thread(bitmap->mddev->thread);
1045         }
1046
1047         printk(KERN_INFO "%s: bitmap initialized from disk: "
1048                 "read %lu/%lu pages, set %lu bits\n",
1049                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1050
1051         return 0;
1052
1053  err:
1054         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1055                bmname(bitmap), ret);
1056         return ret;
1057 }
1058
1059 void bitmap_write_all(struct bitmap *bitmap)
1060 {
1061         /* We don't actually write all bitmap blocks here,
1062          * just flag them as needing to be written
1063          */
1064         int i;
1065
1066         for (i=0; i < bitmap->file_pages; i++)
1067                 set_page_attr(bitmap, bitmap->filemap[i],
1068                               BITMAP_PAGE_NEEDWRITE);
1069 }
1070
1071
1072 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1073 {
1074         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1075         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1076         bitmap->bp[page].count += inc;
1077 /*
1078         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
1079                               (unsigned long long)offset, inc, bitmap->bp[page].count);
1080 */
1081         bitmap_checkfree(bitmap, page);
1082 }
1083 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1084                                             sector_t offset, int *blocks,
1085                                             int create);
1086
1087 /*
1088  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1089  *                      out to disk
1090  */
1091
1092 void bitmap_daemon_work(mddev_t *mddev)
1093 {
1094         struct bitmap *bitmap;
1095         unsigned long j;
1096         unsigned long flags;
1097         struct page *page = NULL, *lastpage = NULL;
1098         int blocks;
1099         void *paddr;
1100
1101         /* Use a mutex to guard daemon_work against
1102          * bitmap_destroy.
1103          */
1104         mutex_lock(&mddev->bitmap_info.mutex);
1105         bitmap = mddev->bitmap;
1106         if (bitmap == NULL) {
1107                 mutex_unlock(&mddev->bitmap_info.mutex);
1108                 return;
1109         }
1110         if (time_before(jiffies, bitmap->daemon_lastrun
1111                         + bitmap->mddev->bitmap_info.daemon_sleep))
1112                 goto done;
1113
1114         bitmap->daemon_lastrun = jiffies;
1115         if (bitmap->allclean) {
1116                 bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1117                 goto done;
1118         }
1119         bitmap->allclean = 1;
1120
1121         spin_lock_irqsave(&bitmap->lock, flags);
1122         for (j = 0; j < bitmap->chunks; j++) {
1123                 bitmap_counter_t *bmc;
1124                 if (!bitmap->filemap)
1125                         /* error or shutdown */
1126                         break;
1127
1128                 page = filemap_get_page(bitmap, j);
1129
1130                 if (page != lastpage) {
1131                         /* skip this page unless it's marked as needing cleaning */
1132                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1133                                 int need_write = test_page_attr(bitmap, page,
1134                                                                 BITMAP_PAGE_NEEDWRITE);
1135                                 if (need_write)
1136                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1137
1138                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1139                                 if (need_write) {
1140                                         write_page(bitmap, page, 0);
1141                                         bitmap->allclean = 0;
1142                                 }
1143                                 spin_lock_irqsave(&bitmap->lock, flags);
1144                                 j |= (PAGE_BITS - 1);
1145                                 continue;
1146                         }
1147
1148                         /* grab the new page, sync and release the old */
1149                         if (lastpage != NULL) {
1150                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1151                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1152                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1153                                         write_page(bitmap, lastpage, 0);
1154                                 } else {
1155                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1156                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1157                                 }
1158                         } else
1159                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1160                         lastpage = page;
1161
1162                         /* We are possibly going to clear some bits, so make
1163                          * sure that events_cleared is up-to-date.
1164                          */
1165                         if (bitmap->need_sync) {
1166                                 bitmap_super_t *sb;
1167                                 bitmap->need_sync = 0;
1168                                 sb = kmap_atomic(bitmap->sb_page, KM_USER0);
1169                                 sb->events_cleared =
1170                                         cpu_to_le64(bitmap->events_cleared);
1171                                 kunmap_atomic(sb, KM_USER0);
1172                                 write_page(bitmap, bitmap->sb_page, 1);
1173                         }
1174                         spin_lock_irqsave(&bitmap->lock, flags);
1175                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1176                 }
1177                 bmc = bitmap_get_counter(bitmap,
1178                                          (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1179                                          &blocks, 0);
1180                 if (bmc) {
1181 /*
1182   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1183 */
1184                         if (*bmc)
1185                                 bitmap->allclean = 0;
1186
1187                         if (*bmc == 2) {
1188                                 *bmc=1; /* maybe clear the bit next time */
1189                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1190                         } else if (*bmc == 1) {
1191                                 /* we can clear the bit */
1192                                 *bmc = 0;
1193                                 bitmap_count_page(bitmap,
1194                                                   (sector_t)j << CHUNK_BLOCK_SHIFT(bitmap),
1195                                                   -1);
1196
1197                                 /* clear the bit */
1198                                 paddr = kmap_atomic(page, KM_USER0);
1199                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1200                                         clear_bit(file_page_offset(j), paddr);
1201                                 else
1202                                         ext2_clear_bit(file_page_offset(j), paddr);
1203                                 kunmap_atomic(paddr, KM_USER0);
1204                         }
1205                 } else
1206                         j |= PAGE_COUNTER_MASK;
1207         }
1208         spin_unlock_irqrestore(&bitmap->lock, flags);
1209
1210         /* now sync the final page */
1211         if (lastpage != NULL) {
1212                 spin_lock_irqsave(&bitmap->lock, flags);
1213                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1214                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1215                         spin_unlock_irqrestore(&bitmap->lock, flags);
1216                         write_page(bitmap, lastpage, 0);
1217                 } else {
1218                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1219                         spin_unlock_irqrestore(&bitmap->lock, flags);
1220                 }
1221         }
1222
1223  done:
1224         if (bitmap->allclean == 0)
1225                 bitmap->mddev->thread->timeout =
1226                         bitmap->mddev->bitmap_info.daemon_sleep;
1227         mutex_unlock(&mddev->bitmap_info.mutex);
1228 }
1229
1230 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1231                                             sector_t offset, int *blocks,
1232                                             int create)
1233 __releases(bitmap->lock)
1234 __acquires(bitmap->lock)
1235 {
1236         /* If 'create', we might release the lock and reclaim it.
1237          * The lock must have been taken with interrupts enabled.
1238          * If !create, we don't release the lock.
1239          */
1240         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1241         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1242         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1243         sector_t csize;
1244
1245         if (bitmap_checkpage(bitmap, page, create) < 0) {
1246                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1247                 *blocks = csize - (offset & (csize- 1));
1248                 return NULL;
1249         }
1250         /* now locked ... */
1251
1252         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1253                 /* should we use the first or second counter field
1254                  * of the hijacked pointer? */
1255                 int hi = (pageoff > PAGE_COUNTER_MASK);
1256                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1257                                           PAGE_COUNTER_SHIFT - 1);
1258                 *blocks = csize - (offset & (csize- 1));
1259                 return  &((bitmap_counter_t *)
1260                           &bitmap->bp[page].map)[hi];
1261         } else { /* page is allocated */
1262                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1263                 *blocks = csize - (offset & (csize- 1));
1264                 return (bitmap_counter_t *)
1265                         &(bitmap->bp[page].map[pageoff]);
1266         }
1267 }
1268
1269 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1270 {
1271         if (!bitmap) return 0;
1272
1273         if (behind) {
1274                 atomic_inc(&bitmap->behind_writes);
1275                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1276                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1277         }
1278
1279         while (sectors) {
1280                 int blocks;
1281                 bitmap_counter_t *bmc;
1282
1283                 spin_lock_irq(&bitmap->lock);
1284                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1285                 if (!bmc) {
1286                         spin_unlock_irq(&bitmap->lock);
1287                         return 0;
1288                 }
1289
1290                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1291                         DEFINE_WAIT(__wait);
1292                         /* note that it is safe to do the prepare_to_wait
1293                          * after the test as long as we do it before dropping
1294                          * the spinlock.
1295                          */
1296                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1297                                         TASK_UNINTERRUPTIBLE);
1298                         spin_unlock_irq(&bitmap->lock);
1299                         blk_unplug(bitmap->mddev->queue);
1300                         schedule();
1301                         finish_wait(&bitmap->overflow_wait, &__wait);
1302                         continue;
1303                 }
1304
1305                 switch(*bmc) {
1306                 case 0:
1307                         bitmap_file_set_bit(bitmap, offset);
1308                         bitmap_count_page(bitmap,offset, 1);
1309                         blk_plug_device_unlocked(bitmap->mddev->queue);
1310                         /* fall through */
1311                 case 1:
1312                         *bmc = 2;
1313                 }
1314
1315                 (*bmc)++;
1316
1317                 spin_unlock_irq(&bitmap->lock);
1318
1319                 offset += blocks;
1320                 if (sectors > blocks)
1321                         sectors -= blocks;
1322                 else sectors = 0;
1323         }
1324         bitmap->allclean = 0;
1325         return 0;
1326 }
1327
1328 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1329                      int success, int behind)
1330 {
1331         if (!bitmap) return;
1332         if (behind) {
1333                 atomic_dec(&bitmap->behind_writes);
1334                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1335                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1336         }
1337         if (bitmap->mddev->degraded)
1338                 /* Never clear bits or update events_cleared when degraded */
1339                 success = 0;
1340
1341         while (sectors) {
1342                 int blocks;
1343                 unsigned long flags;
1344                 bitmap_counter_t *bmc;
1345
1346                 spin_lock_irqsave(&bitmap->lock, flags);
1347                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1348                 if (!bmc) {
1349                         spin_unlock_irqrestore(&bitmap->lock, flags);
1350                         return;
1351                 }
1352
1353                 if (success &&
1354                     bitmap->events_cleared < bitmap->mddev->events) {
1355                         bitmap->events_cleared = bitmap->mddev->events;
1356                         bitmap->need_sync = 1;
1357                 }
1358
1359                 if (!success && ! (*bmc & NEEDED_MASK))
1360                         *bmc |= NEEDED_MASK;
1361
1362                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1363                         wake_up(&bitmap->overflow_wait);
1364
1365                 (*bmc)--;
1366                 if (*bmc <= 2) {
1367                         set_page_attr(bitmap,
1368                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1369                                       BITMAP_PAGE_CLEAN);
1370                 }
1371                 spin_unlock_irqrestore(&bitmap->lock, flags);
1372                 offset += blocks;
1373                 if (sectors > blocks)
1374                         sectors -= blocks;
1375                 else sectors = 0;
1376         }
1377 }
1378
1379 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1380                                int degraded)
1381 {
1382         bitmap_counter_t *bmc;
1383         int rv;
1384         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1385                 *blocks = 1024;
1386                 return 1; /* always resync if no bitmap */
1387         }
1388         spin_lock_irq(&bitmap->lock);
1389         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1390         rv = 0;
1391         if (bmc) {
1392                 /* locked */
1393                 if (RESYNC(*bmc))
1394                         rv = 1;
1395                 else if (NEEDED(*bmc)) {
1396                         rv = 1;
1397                         if (!degraded) { /* don't set/clear bits if degraded */
1398                                 *bmc |= RESYNC_MASK;
1399                                 *bmc &= ~NEEDED_MASK;
1400                         }
1401                 }
1402         }
1403         spin_unlock_irq(&bitmap->lock);
1404         bitmap->allclean = 0;
1405         return rv;
1406 }
1407
1408 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1409                       int degraded)
1410 {
1411         /* bitmap_start_sync must always report on multiples of whole
1412          * pages, otherwise resync (which is very PAGE_SIZE based) will
1413          * get confused.
1414          * So call __bitmap_start_sync repeatedly (if needed) until
1415          * At least PAGE_SIZE>>9 blocks are covered.
1416          * Return the 'or' of the result.
1417          */
1418         int rv = 0;
1419         int blocks1;
1420
1421         *blocks = 0;
1422         while (*blocks < (PAGE_SIZE>>9)) {
1423                 rv |= __bitmap_start_sync(bitmap, offset,
1424                                           &blocks1, degraded);
1425                 offset += blocks1;
1426                 *blocks += blocks1;
1427         }
1428         return rv;
1429 }
1430
1431 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1432 {
1433         bitmap_counter_t *bmc;
1434         unsigned long flags;
1435 /*
1436         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1437 */      if (bitmap == NULL) {
1438                 *blocks = 1024;
1439                 return;
1440         }
1441         spin_lock_irqsave(&bitmap->lock, flags);
1442         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1443         if (bmc == NULL)
1444                 goto unlock;
1445         /* locked */
1446 /*
1447         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1448 */
1449         if (RESYNC(*bmc)) {
1450                 *bmc &= ~RESYNC_MASK;
1451
1452                 if (!NEEDED(*bmc) && aborted)
1453                         *bmc |= NEEDED_MASK;
1454                 else {
1455                         if (*bmc <= 2) {
1456                                 set_page_attr(bitmap,
1457                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1458                                               BITMAP_PAGE_CLEAN);
1459                         }
1460                 }
1461         }
1462  unlock:
1463         spin_unlock_irqrestore(&bitmap->lock, flags);
1464         bitmap->allclean = 0;
1465 }
1466
1467 void bitmap_close_sync(struct bitmap *bitmap)
1468 {
1469         /* Sync has finished, and any bitmap chunks that weren't synced
1470          * properly have been aborted.  It remains to us to clear the
1471          * RESYNC bit wherever it is still on
1472          */
1473         sector_t sector = 0;
1474         int blocks;
1475         if (!bitmap)
1476                 return;
1477         while (sector < bitmap->mddev->resync_max_sectors) {
1478                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1479                 sector += blocks;
1480         }
1481 }
1482
1483 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1484 {
1485         sector_t s = 0;
1486         int blocks;
1487
1488         if (!bitmap)
1489                 return;
1490         if (sector == 0) {
1491                 bitmap->last_end_sync = jiffies;
1492                 return;
1493         }
1494         if (time_before(jiffies, (bitmap->last_end_sync
1495                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1496                 return;
1497         wait_event(bitmap->mddev->recovery_wait,
1498                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1499
1500         bitmap->mddev->curr_resync_completed = bitmap->mddev->curr_resync;
1501         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1502         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1503         s = 0;
1504         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1505                 bitmap_end_sync(bitmap, s, &blocks, 0);
1506                 s += blocks;
1507         }
1508         bitmap->last_end_sync = jiffies;
1509         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1510 }
1511
1512 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1513 {
1514         /* For each chunk covered by any of these sectors, set the
1515          * counter to 1 and set resync_needed.  They should all
1516          * be 0 at this point
1517          */
1518
1519         int secs;
1520         bitmap_counter_t *bmc;
1521         spin_lock_irq(&bitmap->lock);
1522         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1523         if (!bmc) {
1524                 spin_unlock_irq(&bitmap->lock);
1525                 return;
1526         }
1527         if (! *bmc) {
1528                 struct page *page;
1529                 *bmc = 1 | (needed?NEEDED_MASK:0);
1530                 bitmap_count_page(bitmap, offset, 1);
1531                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1532                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1533         }
1534         spin_unlock_irq(&bitmap->lock);
1535         bitmap->allclean = 0;
1536 }
1537
1538 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1539 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1540 {
1541         unsigned long chunk;
1542
1543         for (chunk = s; chunk <= e; chunk++) {
1544                 sector_t sec = (sector_t)chunk << CHUNK_BLOCK_SHIFT(bitmap);
1545                 bitmap_set_memory_bits(bitmap, sec, 1);
1546                 bitmap_file_set_bit(bitmap, sec);
1547         }
1548 }
1549
1550 /*
1551  * flush out any pending updates
1552  */
1553 void bitmap_flush(mddev_t *mddev)
1554 {
1555         struct bitmap *bitmap = mddev->bitmap;
1556         long sleep;
1557
1558         if (!bitmap) /* there was no bitmap */
1559                 return;
1560
1561         /* run the daemon_work three time to ensure everything is flushed
1562          * that can be
1563          */
1564         sleep = mddev->bitmap_info.daemon_sleep * 2;
1565         bitmap->daemon_lastrun -= sleep;
1566         bitmap_daemon_work(mddev);
1567         bitmap->daemon_lastrun -= sleep;
1568         bitmap_daemon_work(mddev);
1569         bitmap->daemon_lastrun -= sleep;
1570         bitmap_daemon_work(mddev);
1571         bitmap_update_sb(bitmap);
1572 }
1573
1574 /*
1575  * free memory that was allocated
1576  */
1577 static void bitmap_free(struct bitmap *bitmap)
1578 {
1579         unsigned long k, pages;
1580         struct bitmap_page *bp;
1581
1582         if (!bitmap) /* there was no bitmap */
1583                 return;
1584
1585         /* release the bitmap file and kill the daemon */
1586         bitmap_file_put(bitmap);
1587
1588         bp = bitmap->bp;
1589         pages = bitmap->pages;
1590
1591         /* free all allocated memory */
1592
1593         if (bp) /* deallocate the page memory */
1594                 for (k = 0; k < pages; k++)
1595                         if (bp[k].map && !bp[k].hijacked)
1596                                 kfree(bp[k].map);
1597         kfree(bp);
1598         kfree(bitmap);
1599 }
1600
1601 void bitmap_destroy(mddev_t *mddev)
1602 {
1603         struct bitmap *bitmap = mddev->bitmap;
1604
1605         if (!bitmap) /* there was no bitmap */
1606                 return;
1607
1608         mutex_lock(&mddev->bitmap_info.mutex);
1609         mddev->bitmap = NULL; /* disconnect from the md device */
1610         mutex_unlock(&mddev->bitmap_info.mutex);
1611         if (mddev->thread)
1612                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1613
1614         bitmap_free(bitmap);
1615 }
1616
1617 /*
1618  * initialize the bitmap structure
1619  * if this returns an error, bitmap_destroy must be called to do clean up
1620  */
1621 int bitmap_create(mddev_t *mddev)
1622 {
1623         struct bitmap *bitmap;
1624         sector_t blocks = mddev->resync_max_sectors;
1625         unsigned long chunks;
1626         unsigned long pages;
1627         struct file *file = mddev->bitmap_info.file;
1628         int err;
1629         sector_t start;
1630
1631         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1632
1633         if (!file && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */
1634                 return 0;
1635
1636         BUG_ON(file && mddev->bitmap_info.offset);
1637
1638         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1639         if (!bitmap)
1640                 return -ENOMEM;
1641
1642         spin_lock_init(&bitmap->lock);
1643         atomic_set(&bitmap->pending_writes, 0);
1644         init_waitqueue_head(&bitmap->write_wait);
1645         init_waitqueue_head(&bitmap->overflow_wait);
1646
1647         bitmap->mddev = mddev;
1648
1649         bitmap->file = file;
1650         if (file) {
1651                 get_file(file);
1652                 /* As future accesses to this file will use bmap,
1653                  * and bypass the page cache, we must sync the file
1654                  * first.
1655                  */
1656                 vfs_fsync(file, file->f_dentry, 1);
1657         }
1658         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1659         err = bitmap_read_sb(bitmap);
1660         if (err)
1661                 goto error;
1662
1663         bitmap->chunkshift = ffz(~mddev->bitmap_info.chunksize);
1664
1665         /* now that chunksize and chunkshift are set, we can use these macros */
1666         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) >>
1667                         CHUNK_BLOCK_SHIFT(bitmap);
1668         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1669
1670         BUG_ON(!pages);
1671
1672         bitmap->chunks = chunks;
1673         bitmap->pages = pages;
1674         bitmap->missing_pages = pages;
1675         bitmap->counter_bits = COUNTER_BITS;
1676
1677         bitmap->syncchunk = ~0UL;
1678
1679 #ifdef INJECT_FATAL_FAULT_1
1680         bitmap->bp = NULL;
1681 #else
1682         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1683 #endif
1684         err = -ENOMEM;
1685         if (!bitmap->bp)
1686                 goto error;
1687
1688         /* now that we have some pages available, initialize the in-memory
1689          * bitmap from the on-disk bitmap */
1690         start = 0;
1691         if (mddev->degraded == 0
1692             || bitmap->events_cleared == mddev->events)
1693                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1694                 start = mddev->recovery_cp;
1695         err = bitmap_init_from_disk(bitmap, start);
1696
1697         if (err)
1698                 goto error;
1699
1700         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1701                 pages, bmname(bitmap));
1702
1703         mddev->bitmap = bitmap;
1704
1705         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1706         md_wakeup_thread(mddev->thread);
1707
1708         bitmap_update_sb(bitmap);
1709
1710         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1711
1712  error:
1713         bitmap_free(bitmap);
1714         return err;
1715 }
1716
1717 /* the bitmap API -- for raid personalities */
1718 EXPORT_SYMBOL(bitmap_startwrite);
1719 EXPORT_SYMBOL(bitmap_endwrite);
1720 EXPORT_SYMBOL(bitmap_start_sync);
1721 EXPORT_SYMBOL(bitmap_end_sync);
1722 EXPORT_SYMBOL(bitmap_unplug);
1723 EXPORT_SYMBOL(bitmap_close_sync);
1724 EXPORT_SYMBOL(bitmap_cond_end_sync);