2 files changed, 84 insertions, 297 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index a5a260fab824..d45b2cdee6c4 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -94,75 +94,6 @@ xfs_buf_vmap_len(
 }
 
 /*
- *      Page Region interfaces.
- *
- *      For pages in filesystems where the blocksize is smaller than the
- *      pagesize, we use the page->private field (long) to hold a bitmap
- *      of uptodate regions within the page.
- *
- *      Each such region is "bytes per page / bits per long" bytes long.
- *
- *      NBPPR == number-of-bytes-per-page-region
- *      BTOPR == bytes-to-page-region (rounded up)
- *      BTOPRT == bytes-to-page-region-truncated (rounded down)
- */
-#if (BITS_PER_LONG == 32)
-#define PRSHIFT         (PAGE_CACHE_SHIFT - 5)  /* (32 == 1<<5) */
-#elif (BITS_PER_LONG == 64)
-#define PRSHIFT         (PAGE_CACHE_SHIFT - 6)  /* (64 == 1<<6) */
-#else
-#error BITS_PER_LONG must be 32 or 64
-#endif
-#define NBPPR           (PAGE_CACHE_SIZE/BITS_PER_LONG)
-#define BTOPR(b)        (((unsigned int)(b) + (NBPPR - 1)) >> PRSHIFT)
-#define BTOPRT(b)       (((unsigned int)(b) >> PRSHIFT))
-
-STATIC unsigned long
-page_region_mask(
-        size_t          offset,
-        size_t          length)
-{
-        unsigned long   mask;
-        int             first, final;
-
-        first = BTOPR(offset);
-        final = BTOPRT(offset + length - 1);
-        first = min(first, final);
-
-        mask = ~0UL;
-        mask <<= BITS_PER_LONG - (final - first);
-        mask >>= BITS_PER_LONG - (final);
-
-        ASSERT(offset + length <= PAGE_CACHE_SIZE);
-        ASSERT((final - first) < BITS_PER_LONG && (final - first) >= 0);
-
-        return mask;
-}
-
-STATIC void
-set_page_region(
-        struct page     *page,
-        size_t          offset,
-        size_t          length)
-{
-        set_page_private(page,
-                page_private(page) | page_region_mask(offset, length));
-        if (page_private(page) == ~0UL)
-                SetPageUptodate(page);
-}
-
-STATIC int
-test_page_region(
-        struct page     *page,
-        size_t          offset,
-        size_t          length)
-{
-        unsigned long   mask = page_region_mask(offset, length);
-
-        return (mask && (page_private(page) & mask) == mask);
-}
-
-/*
  * xfs_buf_lru_add - add a buffer to the LRU.
  *
  * The LRU takes a new reference to the buffer so that it will only be freed
@@ -332,7 +263,7 @@ xfs_buf_free(
 
         ASSERT(list_empty(&bp->b_lru));
 
-        if (bp->b_flags & (_XBF_PAGE_CACHE|_XBF_PAGES)) {
+        if (bp->b_flags & _XBF_PAGES) {
                 uint            i;
 
                 if (xfs_buf_is_vmapped(bp))
@@ -342,25 +273,22 @@ xfs_buf_free(
                 for (i = 0; i < bp->b_page_count; i++) {
                         struct page     *page = bp->b_pages[i];
 
-                        if (bp->b_flags & _XBF_PAGE_CACHE)
-                                ASSERT(!PagePrivate(page));
-                        page_cache_release(page);
+                        __free_page(page);
                 }
-        }
+        } else if (bp->b_flags & _XBF_KMEM)
+                kmem_free(bp->b_addr);
         _xfs_buf_free_pages(bp);
         xfs_buf_deallocate(bp);
 }
 
 /*
- *      Finds all pages for buffer in question and builds it's page list.
+ * Allocates all the pages for buffer in question and builds it's page list.
  */
 STATIC int
-_xfs_buf_lookup_pages(
+xfs_buf_allocate_memory(
         xfs_buf_t               *bp,
         uint                    flags)
 {
-        struct address_space    *mapping = bp->b_target->bt_mapping;
-        size_t                  blocksize = bp->b_target->bt_bsize;
         size_t                  size = bp->b_count_desired;
         size_t                  nbytes, offset;
         gfp_t                   gfp_mask = xb_to_gfp(flags);
@@ -369,29 +297,55 @@ _xfs_buf_lookup_pages(
         xfs_off_t               end;
         int                     error;
 
+        /*
+         * for buffers that are contained within a single page, just allocate
+         * the memory from the heap - there's no need for the complexity of
+         * page arrays to keep allocation down to order 0.
+         */
+        if (bp->b_buffer_length < PAGE_SIZE) {
+                bp->b_addr = kmem_alloc(bp->b_buffer_length, xb_to_km(flags));
+                if (!bp->b_addr) {
+                        /* low memory - use alloc_page loop instead */
+                        goto use_alloc_page;
+                }
+
+                if (((unsigned long)(bp->b_addr + bp->b_buffer_length - 1) &
+                                                                PAGE_MASK) !=
+                    ((unsigned long)bp->b_addr & PAGE_MASK)) {
+                        /* b_addr spans two pages - use alloc_page instead */
+                        kmem_free(bp->b_addr);
+                        bp->b_addr = NULL;
+                        goto use_alloc_page;
+                }
+                bp->b_offset = offset_in_page(bp->b_addr);
+                bp->b_pages = bp->b_page_array;
+                bp->b_pages[0] = virt_to_page(bp->b_addr);
+                bp->b_page_count = 1;
+                bp->b_flags |= XBF_MAPPED | _XBF_KMEM;
+                return 0;
+        }
+
+use_alloc_page:
         end = bp->b_file_offset + bp->b_buffer_length;
         page_count = xfs_buf_btoc(end) - xfs_buf_btoct(bp->b_file_offset);
-
         error = _xfs_buf_get_pages(bp, page_count, flags);
         if (unlikely(error))
                 return error;
-        bp->b_flags |= _XBF_PAGE_CACHE;
 
         offset = bp->b_offset;
-        first = bp->b_file_offset >> PAGE_CACHE_SHIFT;
+        first = bp->b_file_offset >> PAGE_SHIFT;
+        bp->b_flags |= _XBF_PAGES;
 
         for (i = 0; i < bp->b_page_count; i++) {
                 struct page     *page;
                 uint            retries = 0;
-
-              retry:
-                page = find_or_create_page(mapping, first + i, gfp_mask);
+retry:
+                page = alloc_page(gfp_mask);
                 if (unlikely(page == NULL)) {
                         if (flags & XBF_READ_AHEAD) {
                                 bp->b_page_count = i;
-                                for (i = 0; i < bp->b_page_count; i++)
-                                        unlock_page(bp->b_pages[i]);
-                                return -ENOMEM;
+                                error = ENOMEM;
+                                goto out_free_pages;
                         }
 
                         /*
@@ -412,33 +366,16 @@ _xfs_buf_lookup_pages(
 
                 XFS_STATS_INC(xb_page_found);
 
-                nbytes = min_t(size_t, size, PAGE_CACHE_SIZE - offset);
+                nbytes = min_t(size_t, size, PAGE_SIZE - offset);
                 size -= nbytes;
-
-                ASSERT(!PagePrivate(page));
-                if (!PageUptodate(page)) {
-                        page_count--;
-                        if (blocksize >= PAGE_CACHE_SIZE) {
-                                if (flags & XBF_READ)
-                                        bp->b_flags |= _XBF_PAGE_LOCKED;
-                        } else if (!PagePrivate(page)) {
-                                if (test_page_region(page, offset, nbytes))
-                                        page_count++;
-                        }
-                }
-
                 bp->b_pages[i] = page;
                 offset = 0;
         }
+        return 0;
 
-        if (!(bp->b_flags & _XBF_PAGE_LOCKED)) {
-                for (i = 0; i < bp->b_page_count; i++)
-                        unlock_page(bp->b_pages[i]);
-        }
-
-        if (page_count == bp->b_page_count)
-                bp->b_flags |= XBF_DONE;
-
+out_free_pages:
+        for (i = 0; i < bp->b_page_count; i++)
+                __free_page(bp->b_pages[i]);
         return error;
 }
 
@@ -450,8 +387,9 @@ _xfs_buf_map_pages(
         xfs_buf_t               *bp,
         uint                    flags)
 {
-        /* A single page buffer is always mappable */
+        ASSERT(bp->b_flags & _XBF_PAGES);
         if (bp->b_page_count == 1) {
+                /* A single page buffer is always mappable */
                 bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
                 bp->b_flags |= XBF_MAPPED;
         } else if (flags & XBF_MAPPED) {
@@ -576,9 +514,14 @@ found:
                 }
         }
 
+        /*
+         * if the buffer is stale, clear all the external state associated with
+         * it. We need to keep flags such as how we allocated the buffer memory
+         * intact here.
+         */
         if (bp->b_flags & XBF_STALE) {
                 ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
-                bp->b_flags &= XBF_MAPPED;
+                bp->b_flags &= XBF_MAPPED | _XBF_KMEM | _XBF_PAGES;
         }
 
         trace_xfs_buf_find(bp, flags, _RET_IP_);
@@ -599,7 +542,7 @@ xfs_buf_get(
         xfs_buf_flags_t         flags)
 {
         xfs_buf_t               *bp, *new_bp;
-        int                     error = 0, i;
+        int                     error = 0;
 
         new_bp = xfs_buf_allocate(flags);
         if (unlikely(!new_bp))
@@ -607,7 +550,7 @@ xfs_buf_get(
 
         bp = _xfs_buf_find(target, ioff, isize, flags, new_bp);
         if (bp == new_bp) {
-                error = _xfs_buf_lookup_pages(bp, flags);
+                error = xfs_buf_allocate_memory(bp, flags);
                 if (error)
                         goto no_buffer;
         } else {
@@ -616,9 +559,6 @@ xfs_buf_get(
                         return NULL;
         }
 
-        for (i = 0; i < bp->b_page_count; i++)
-                mark_page_accessed(bp->b_pages[i]);
-
         if (!(bp->b_flags & XBF_MAPPED)) {
                 error = _xfs_buf_map_pages(bp, flags);
                 if (unlikely(error)) {
@@ -719,8 +659,7 @@ xfs_buf_readahead(
 {
         struct backing_dev_info *bdi;
 
-        bdi = target->bt_mapping->backing_dev_info;
-        if (bdi_read_congested(bdi))
+        if (bdi_read_congested(target->bt_bdi))
                 return;
 
         xfs_buf_read(target, ioff, isize,
@@ -798,10 +737,10 @@ xfs_buf_associate_memory(
         size_t                  buflen;
         int                     page_count;
 
-        pageaddr = (unsigned long)mem & PAGE_CACHE_MASK;
+        pageaddr = (unsigned long)mem & PAGE_MASK;
         offset = (unsigned long)mem - pageaddr;
-        buflen = PAGE_CACHE_ALIGN(len + offset);
-        page_count = buflen >> PAGE_CACHE_SHIFT;
+        buflen = PAGE_ALIGN(len + offset);
+        page_count = buflen >> PAGE_SHIFT;
 
         /* Free any previous set of page pointers */
         if (bp->b_pages)
@@ -818,13 +757,12 @@ xfs_buf_associate_memory(
 
         for (i = 0; i < bp->b_page_count; i++) {
                 bp->b_pages[i] = mem_to_page((void *)pageaddr);
-                pageaddr += PAGE_CACHE_SIZE;
+                pageaddr += PAGE_SIZE;
         }
 
         bp->b_count_desired = len;
         bp->b_buffer_length = buflen;
         bp->b_flags |= XBF_MAPPED;
-        bp->b_flags &= ~_XBF_PAGE_LOCKED;
 
         return 0;
 }
@@ -931,20 +869,7 @@ xfs_buf_rele(
 
 
 /*
- *      Mutual exclusion on buffers.  Locking model:
- *
- *      Buffers associated with inodes for which buffer locking
- *      is not enabled are not protected by semaphores, and are
- *      assumed to be exclusively owned by the caller.  There is a
- *      spinlock in the buffer, used by the caller when concurrent
- *      access is possible.
- */
-
-/*
- *      Locks a buffer object, if it is not already locked.  Note that this in
- *      no way locks the underlying pages, so it is only useful for
- *      synchronizing concurrent use of buffer objects, not for synchronizing
- *      independent access to the underlying pages.
+ *      Lock a buffer object, if it is not already locked.
  *
  *      If we come across a stale, pinned, locked buffer, we know that we are
  *      being asked to lock a buffer that has been reallocated. Because it is
@@ -978,10 +903,7 @@ xfs_buf_lock_value(
 }
 
 /*
- *      Locks a buffer object.
- *      Note that this in no way locks the underlying pages, so it is only
- *      useful for synchronizing concurrent use of buffer objects, not for
- *      synchronizing independent access to the underlying pages.
+ *      Lock a buffer object.
  *
  *      If we come across a stale, pinned, locked buffer, we know that we
  *      are being asked to lock a buffer that has been reallocated. Because
@@ -998,7 +920,7 @@ xfs_buf_lock(
         if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
                 xfs_log_force(bp->b_target->bt_mount, 0);
         if (atomic_read(&bp->b_io_remaining))
-                blk_run_address_space(bp->b_target->bt_mapping);
+                blk_run_backing_dev(bp->b_target->bt_bdi, NULL);
         down(&bp->b_sema);
         XB_SET_OWNER(bp);
 
@@ -1043,7 +965,7 @@ xfs_buf_wait_unpin(
                 if (atomic_read(&bp->b_pin_count) == 0)
                         break;
                 if (atomic_read(&bp->b_io_remaining))
-                        blk_run_address_space(bp->b_target->bt_mapping);
+                        blk_run_backing_dev(bp->b_target->bt_bdi, NULL);
                 schedule();
         }
         remove_wait_queue(&bp->b_waiters, &wait);
@@ -1256,10 +1178,8 @@ _xfs_buf_ioend(
         xfs_buf_t               *bp,
         int                     schedule)
 {
-        if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
-                bp->b_flags &= ~_XBF_PAGE_LOCKED;
+        if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
                 xfs_buf_ioend(bp, schedule);
-        }
 }
 
 STATIC void
@@ -1268,35 +1188,12 @@ xfs_buf_bio_end_io(
         int                     error)
 {
         xfs_buf_t               *bp = (xfs_buf_t *)bio->bi_private;
-        unsigned int            blocksize = bp->b_target->bt_bsize;
-        struct bio_vec          *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
 
         xfs_buf_ioerror(bp, -error);
 
         if (!error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ))
                 invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
 
-        do {
-                struct page     *page = bvec->bv_page;
-
-                ASSERT(!PagePrivate(page));
-                if (unlikely(bp->b_error)) {
-                        if (bp->b_flags & XBF_READ)
-                                ClearPageUptodate(page);
-                } else if (blocksize >= PAGE_CACHE_SIZE) {
-                        SetPageUptodate(page);
-                } else if (!PagePrivate(page) &&
-                                (bp->b_flags & _XBF_PAGE_CACHE)) {
-                        set_page_region(page, bvec->bv_offset, bvec->bv_len);
-                }
-
-                if (--bvec >= bio->bi_io_vec)
-                        prefetchw(&bvec->bv_page->flags);
-
-                if (bp->b_flags & _XBF_PAGE_LOCKED)
-                        unlock_page(page);
-        } while (bvec >= bio->bi_io_vec);
-
         _xfs_buf_ioend(bp, 1);
         bio_put(bio);
 }
@@ -1310,7 +1207,6 @@ _xfs_buf_ioapply(
         int                     offset = bp->b_offset;
         int                     size = bp->b_count_desired;
         sector_t                sector = bp->b_bn;
-        unsigned int            blocksize = bp->b_target->bt_bsize;
 
         total_nr_pages = bp->b_page_count;
         map_i = 0;
@@ -1331,29 +1227,6 @@ _xfs_buf_ioapply(
                      (bp->b_flags & XBF_READ_AHEAD) ? READA : READ;
         }
 
-        /* Special code path for reading a sub page size buffer in --
-         * we populate up the whole page, and hence the other metadata
-         * in the same page.  This optimization is only valid when the
-         * filesystem block size is not smaller than the page size.
-         */
-        if ((bp->b_buffer_length < PAGE_CACHE_SIZE) &&
-            ((bp->b_flags & (XBF_READ|_XBF_PAGE_LOCKED)) ==
-              (XBF_READ|_XBF_PAGE_LOCKED)) &&
-            (blocksize >= PAGE_CACHE_SIZE)) {
-                bio = bio_alloc(GFP_NOIO, 1);
-
-                bio->bi_bdev = bp->b_target->bt_bdev;
-                bio->bi_sector = sector - (offset >> BBSHIFT);
-                bio->bi_end_io = xfs_buf_bio_end_io;
-                bio->bi_private = bp;
-
-                bio_add_page(bio, bp->b_pages[0], PAGE_CACHE_SIZE, 0);
-                size = 0;
-
-                atomic_inc(&bp->b_io_remaining);
-
-                goto submit_io;
-        }
 
 next_chunk:
         atomic_inc(&bp->b_io_remaining);
@@ -1367,8 +1240,9 @@ next_chunk:
         bio->bi_end_io = xfs_buf_bio_end_io;
         bio->bi_private = bp;
 
+
         for (; size && nr_pages; nr_pages--, map_i++) {
-                int     rbytes, nbytes = PAGE_CACHE_SIZE - offset;
+                int     rbytes, nbytes = PAGE_SIZE - offset;
 
                 if (nbytes > size)
                         nbytes = size;
@@ -1383,7 +1257,6 @@ next_chunk:
                 total_nr_pages--;
         }
 
-submit_io:
         if (likely(bio->bi_size)) {
                 if (xfs_buf_is_vmapped(bp)) {
                         flush_kernel_vmap_range(bp->b_addr,
@@ -1393,18 +1266,7 @@ submit_io:
                 if (size)
                         goto next_chunk;
         } else {
-                /*
-                 * if we get here, no pages were added to the bio. However,
-                 * we can't just error out here - if the pages are locked then
-                 * we have to unlock them otherwise we can hang on a later
-                 * access to the page.
-                 */
                 xfs_buf_ioerror(bp, EIO);
-                if (bp->b_flags & _XBF_PAGE_LOCKED) {
-                        int i;
-                        for (i = 0; i < bp->b_page_count; i++)
-                                unlock_page(bp->b_pages[i]);
-                }
                 bio_put(bio);
         }
 }
@@ -1450,7 +1312,7 @@ xfs_buf_iowait(
         trace_xfs_buf_iowait(bp, _RET_IP_);
 
         if (atomic_read(&bp->b_io_remaining))
-                blk_run_address_space(bp->b_target->bt_mapping);
+                blk_run_backing_dev(bp->b_target->bt_bdi, NULL);
         wait_for_completion(&bp->b_iowait);
 
         trace_xfs_buf_iowait_done(bp, _RET_IP_);
@@ -1468,8 +1330,8 @@ xfs_buf_offset(
                 return XFS_BUF_PTR(bp) + offset;
 
         offset += bp->b_offset;
-        page = bp->b_pages[offset >> PAGE_CACHE_SHIFT];
-        return (xfs_caddr_t)page_address(page) + (offset & (PAGE_CACHE_SIZE-1));
+        page = bp->b_pages[offset >> PAGE_SHIFT];
+        return (xfs_caddr_t)page_address(page) + (offset & (PAGE_SIZE-1));
 }
 
 /*
@@ -1491,9 +1353,9 @@ xfs_buf_iomove(
                 page = bp->b_pages[xfs_buf_btoct(boff + bp->b_offset)];
                 cpoff = xfs_buf_poff(boff + bp->b_offset);
                 csize = min_t(size_t,
-                              PAGE_CACHE_SIZE-cpoff, bp->b_count_desired-boff);
+                              PAGE_SIZE-cpoff, bp->b_count_desired-boff);
 
-                ASSERT(((csize + cpoff) <= PAGE_CACHE_SIZE));
+                ASSERT(((csize + cpoff) <= PAGE_SIZE));
 
                 switch (mode) {
                 case XBRW_ZERO:
@@ -1606,7 +1468,6 @@ xfs_free_buftarg(
         xfs_flush_buftarg(btp, 1);
         if (mp->m_flags & XFS_MOUNT_BARRIER)
                 xfs_blkdev_issue_flush(btp);
-        iput(btp->bt_mapping->host);
 
         kthread_stop(btp->bt_task);
         kmem_free(btp);
@@ -1630,15 +1491,6 @@ xfs_setsize_buftarg_flags(
                 return EINVAL;
         }
 
-        if (verbose &&
-            (PAGE_CACHE_SIZE / BITS_PER_LONG) > sectorsize) {
-                printk(KERN_WARNING
-                        "XFS: %u byte sectors in use on device %s.  "
-                        "This is suboptimal; %u or greater is ideal.\n",
-                        sectorsize, XFS_BUFTARG_NAME(btp),
-                        (unsigned int)PAGE_CACHE_SIZE / BITS_PER_LONG);
-        }
-
         return 0;
 }
 
@@ -1653,7 +1505,7 @@ xfs_setsize_buftarg_early(
         struct block_device     *bdev)
 {
         return xfs_setsize_buftarg_flags(btp,
-                        PAGE_CACHE_SIZE, bdev_logical_block_size(bdev), 0);
+                        PAGE_SIZE, bdev_logical_block_size(bdev), 0);
 }
 
 int
@@ -1666,41 +1518,6 @@ xfs_setsize_buftarg(
 }
 
 STATIC int
-xfs_mapping_buftarg(
-        xfs_buftarg_t           *btp,
-        struct block_device     *bdev)
-{
-        struct backing_dev_info *bdi;
-        struct inode            *inode;
-        struct address_space    *mapping;
-        static const struct address_space_operations mapping_aops = {
-                .sync_page = block_sync_page,
-                .migratepage = fail_migrate_page,
-        };
-
-        inode = new_inode(bdev->bd_inode->i_sb);
-        if (!inode) {
-                printk(KERN_WARNING
-                        "XFS: Cannot allocate mapping inode for device %s\n",
-                        XFS_BUFTARG_NAME(btp));
-                return ENOMEM;
-        }
-        inode->i_ino = get_next_ino();
-        inode->i_mode = S_IFBLK;
-        inode->i_bdev = bdev;
-        inode->i_rdev = bdev->bd_dev;
-        bdi = blk_get_backing_dev_info(bdev);
-        if (!bdi)
-                bdi = &default_backing_dev_info;
-        mapping = &inode->i_data;
-        mapping->a_ops = &mapping_aops;
-        mapping->backing_dev_info = bdi;
-        mapping_set_gfp_mask(mapping, GFP_NOFS);
-        btp->bt_mapping = mapping;
-        return 0;
-}
-
-STATIC int
 xfs_alloc_delwrite_queue(
         xfs_buftarg_t           *btp,
         const char              *fsname)
@@ -1728,12 +1545,14 @@ xfs_alloc_buftarg(
         btp->bt_mount = mp;
         btp->bt_dev =  bdev->bd_dev;
         btp->bt_bdev = bdev;
+        btp->bt_bdi = blk_get_backing_dev_info(bdev);
+        if (!btp->bt_bdi)
+                goto error;
+
         INIT_LIST_HEAD(&btp->bt_lru);
         spin_lock_init(&btp->bt_lru_lock);
         if (xfs_setsize_buftarg_early(btp, bdev))
                 goto error;
-        if (xfs_mapping_buftarg(btp, bdev))
-                goto error;
         if (xfs_alloc_delwrite_queue(btp, fsname))
                 goto error;
         btp->bt_shrinker.shrink = xfs_buftarg_shrink;
@@ -1955,7 +1774,7 @@ xfsbufd(
                         count++;
                 }
                 if (count)
-                        blk_run_address_space(target->bt_mapping);
+                        blk_run_backing_dev(target->bt_bdi, NULL);
 
         } while (!kthread_should_stop());
 
@@ -2003,7 +1822,7 @@ xfs_flush_buftarg(
 
         if (wait) {
                 /* Expedite and wait for IO to complete. */
-                blk_run_address_space(target->bt_mapping);
+                blk_run_backing_dev(target->bt_bdi, NULL);
                 while (!list_empty(&wait_list)) {
                         bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
 
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index cbe65950e524..a9a1c4512645 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -61,30 +61,11 @@ typedef enum {
 #define XBF_DONT_BLOCK  (1 << 16)/* do not block in current thread */
 
 /* flags used only internally */
-#define _XBF_PAGE_CACHE (1 << 17)/* backed by pagecache */
 #define _XBF_PAGES      (1 << 18)/* backed by refcounted pages */
 #define _XBF_RUN_QUEUES (1 << 19)/* run block device task queue */
+#define _XBF_KMEM       (1 << 20)/* backed by heap memory */
 #define _XBF_DELWRI_Q   (1 << 21)/* buffer on delwri queue */
 
-/*
- * Special flag for supporting metadata blocks smaller than a FSB.
- *
- * In this case we can have multiple xfs_buf_t on a single page and
- * need to lock out concurrent xfs_buf_t readers as they only
- * serialise access to the buffer.
- *
- * If the FSB size >= PAGE_CACHE_SIZE case, we have no serialisation
- * between reads of the page. Hence we can have one thread read the
- * page and modify it, but then race with another thread that thinks
- * the page is not up-to-date and hence reads it again.
- *
- * The result is that the first modifcation to the page is lost.
- * This sort of AGF/AGI reading race can happen when unlinking inodes
- * that require truncation and results in the AGI unlinked list
- * modifications being lost.
- */
-#define _XBF_PAGE_LOCKED        (1 << 22)
-
 typedef unsigned int xfs_buf_flags_t;
 
 #define XFS_BUF_FLAGS \
@@ -100,12 +81,10 @@ typedef unsigned int xfs_buf_flags_t;
         { XBF_LOCK,             "LOCK" },       /* should never be set */\
         { XBF_TRYLOCK,          "TRYLOCK" },    /* ditto */\
         { XBF_DONT_BLOCK,       "DONT_BLOCK" }, /* ditto */\
-        { _XBF_PAGE_CACHE,      "PAGE_CACHE" }, \
         { _XBF_PAGES,           "PAGES" }, \
         { _XBF_RUN_QUEUES,      "RUN_QUEUES" }, \
-        { _XBF_DELWRI_Q,        "DELWRI_Q" }, \
-        { _XBF_PAGE_LOCKED,     "PAGE_LOCKED" }
-
+        { _XBF_KMEM,            "KMEM" }, \
+        { _XBF_DELWRI_Q,        "DELWRI_Q" }
 
 typedef enum {
         XBT_FORCE_SLEEP = 0,
@@ -120,7 +99,7 @@ typedef struct xfs_bufhash {
 typedef struct xfs_buftarg {
         dev_t                   bt_dev;
         struct block_device     *bt_bdev;
-        struct address_space    *bt_mapping;
+        struct backing_dev_info *bt_bdi;
         struct xfs_mount        *bt_mount;
         unsigned int            bt_bsize;
         unsigned int            bt_sshift;
@@ -139,17 +118,6 @@ typedef struct xfs_buftarg {
         unsigned int            bt_lru_nr;
 } xfs_buftarg_t;
 
-/*
- *      xfs_buf_t:  Buffer structure for pagecache-based buffers
- *
- * This buffer structure is used by the pagecache buffer management routines
- * to refer to an assembly of pages forming a logical buffer.
- *
- * The buffer structure is used on a temporary basis only, and discarded when
- * released.  The real data storage is recorded in the pagecache. Buffers are
- * hashed to the block device on which the file system resides.
- */
-
 struct xfs_buf;
 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);