1 files changed, 391 insertions, 469 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 286e36e21dae..5e68099db2a5 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -33,7 +33,6 @@
 #include <linux/migrate.h>
 #include <linux/backing-dev.h>
 #include <linux/freezer.h>
-#include <linux/list_sort.h>
 
 #include "xfs_sb.h"
 #include "xfs_inum.h"
@@ -44,12 +43,7 @@
 
 static kmem_zone_t *xfs_buf_zone;
 STATIC int xfsbufd(void *);
-STATIC int xfsbufd_wakeup(struct shrinker *, int, gfp_t);
 STATIC void xfs_buf_delwri_queue(xfs_buf_t *, int);
-static struct shrinker xfs_buf_shake = {
-        .shrink = xfsbufd_wakeup,
-        .seeks = DEFAULT_SEEKS,
-};
 
 static struct workqueue_struct *xfslogd_workqueue;
 struct workqueue_struct *xfsdatad_workqueue;
@@ -99,77 +93,79 @@ xfs_buf_vmap_len(
 }
 
 /*
- *      Page Region interfaces.
+ * xfs_buf_lru_add - add a buffer to the LRU.
  *
- *      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)
+ * The LRU takes a new reference to the buffer so that it will only be freed
+ * once the shrinker takes the buffer off the LRU.
  */
-#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)
+STATIC void
+xfs_buf_lru_add(
+        struct xfs_buf  *bp)
 {
-        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);
+        struct xfs_buftarg *btp = bp->b_target;
 
-        return mask;
+        spin_lock(&btp->bt_lru_lock);
+        if (list_empty(&bp->b_lru)) {
+                atomic_inc(&bp->b_hold);
+                list_add_tail(&bp->b_lru, &btp->bt_lru);
+                btp->bt_lru_nr++;
+        }
+        spin_unlock(&btp->bt_lru_lock);
 }
 
+/*
+ * xfs_buf_lru_del - remove a buffer from the LRU
+ *
+ * The unlocked check is safe here because it only occurs when there are not
+ * b_lru_ref counts left on the inode under the pag->pag_buf_lock. it is there
+ * to optimise the shrinker removing the buffer from the LRU and calling
+ * xfs_buf_free(). i.e. it removes an unnecessary round trip on the
+ * bt_lru_lock.
+ */
 STATIC void
-set_page_region(
-        struct page     *page,
-        size_t          offset,
-        size_t          length)
+xfs_buf_lru_del(
+        struct xfs_buf  *bp)
 {
-        set_page_private(page,
-                page_private(page) | page_region_mask(offset, length));
-        if (page_private(page) == ~0UL)
-                SetPageUptodate(page);
-}
+        struct xfs_buftarg *btp = bp->b_target;
 
-STATIC int
-test_page_region(
-        struct page     *page,
-        size_t          offset,
-        size_t          length)
-{
-        unsigned long   mask = page_region_mask(offset, length);
+        if (list_empty(&bp->b_lru))
+                return;
 
-        return (mask && (page_private(page) & mask) == mask);
+        spin_lock(&btp->bt_lru_lock);
+        if (!list_empty(&bp->b_lru)) {
+                list_del_init(&bp->b_lru);
+                btp->bt_lru_nr--;
+        }
+        spin_unlock(&btp->bt_lru_lock);
 }
 
 /*
- *      Internal xfs_buf_t object manipulation
+ * When we mark a buffer stale, we remove the buffer from the LRU and clear the
+ * b_lru_ref count so that the buffer is freed immediately when the buffer
+ * reference count falls to zero. If the buffer is already on the LRU, we need
+ * to remove the reference that LRU holds on the buffer.
+ *
+ * This prevents build-up of stale buffers on the LRU.
  */
+void
+xfs_buf_stale(
+        struct xfs_buf  *bp)
+{
+        bp->b_flags |= XBF_STALE;
+        atomic_set(&(bp)->b_lru_ref, 0);
+        if (!list_empty(&bp->b_lru)) {
+                struct xfs_buftarg *btp = bp->b_target;
+
+                spin_lock(&btp->bt_lru_lock);
+                if (!list_empty(&bp->b_lru)) {
+                        list_del_init(&bp->b_lru);
+                        btp->bt_lru_nr--;
+                        atomic_dec(&bp->b_hold);
+                }
+                spin_unlock(&btp->bt_lru_lock);
+        }
+        ASSERT(atomic_read(&bp->b_hold) >= 1);
+}
 
 STATIC void
 _xfs_buf_initialize(
@@ -186,10 +182,12 @@ _xfs_buf_initialize(
 
         memset(bp, 0, sizeof(xfs_buf_t));
         atomic_set(&bp->b_hold, 1);
+        atomic_set(&bp->b_lru_ref, 1);
         init_completion(&bp->b_iowait);
+        INIT_LIST_HEAD(&bp->b_lru);
         INIT_LIST_HEAD(&bp->b_list);
-        INIT_LIST_HEAD(&bp->b_hash_list);
-        init_MUTEX_LOCKED(&bp->b_sema); /* held, no waiters */
+        RB_CLEAR_NODE(&bp->b_rbnode);
+        sema_init(&bp->b_sema, 0); /* held, no waiters */
         XB_SET_OWNER(bp);
         bp->b_target = target;
         bp->b_file_offset = range_base;
@@ -262,9 +260,9 @@ xfs_buf_free(
 {
         trace_xfs_buf_free(bp, _RET_IP_);
 
-        ASSERT(list_empty(&bp->b_hash_list));
+        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))
@@ -274,56 +272,77 @@ 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);
         unsigned short          page_count, i;
-        pgoff_t                 first;
         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;
+        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;
                         }
 
                         /*
@@ -333,65 +352,55 @@ _xfs_buf_lookup_pages(
                          * handle buffer allocation failures we can't do much.
                          */
                         if (!(++retries % 100))
-                                printk(KERN_ERR
-                                        "XFS: possible memory allocation "
-                                        "deadlock in %s (mode:0x%x)\n",
+                                xfs_err(NULL,
+                "possible memory allocation deadlock in %s (mode:0x%x)",
                                         __func__, gfp_mask);
 
                         XFS_STATS_INC(xb_page_retries);
-                        xfsbufd_wakeup(NULL, 0, gfp_mask);
                         congestion_wait(BLK_RW_ASYNC, HZ/50);
                         goto retry;
                 }
 
                 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;
 }
 
 /*
- *      Map buffer into kernel address-space if nessecary.
+ *      Map buffer into kernel address-space if necessary.
  */
 STATIC int
 _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) {
-                bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
-                                        -1, PAGE_KERNEL);
-                if (unlikely(bp->b_addr == NULL))
+                int retried = 0;
+
+                do {
+                        bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
+                                                -1, PAGE_KERNEL);
+                        if (bp->b_addr)
+                                break;
+                        vm_unmap_aliases();
+                } while (retried++ <= 1);
+
+                if (!bp->b_addr)
                         return -ENOMEM;
                 bp->b_addr += bp->b_offset;
                 bp->b_flags |= XBF_MAPPED;
@@ -422,8 +431,10 @@ _xfs_buf_find(
 {
         xfs_off_t               range_base;
         size_t                  range_length;
-        xfs_bufhash_t           *hash;
-        xfs_buf_t               *bp, *n;
+        struct xfs_perag        *pag;
+        struct rb_node          **rbp;
+        struct rb_node          *parent;
+        xfs_buf_t               *bp;
 
         range_base = (ioff << BBSHIFT);
         range_length = (isize << BBSHIFT);
@@ -432,14 +443,37 @@ _xfs_buf_find(
         ASSERT(!(range_length < (1 << btp->bt_sshift)));
         ASSERT(!(range_base & (xfs_off_t)btp->bt_smask));
 
-        hash = &btp->bt_hash[hash_long((unsigned long)ioff, btp->bt_hashshift)];
-
-        spin_lock(&hash->bh_lock);
-
-        list_for_each_entry_safe(bp, n, &hash->bh_list, b_hash_list) {
-                ASSERT(btp == bp->b_target);
-                if (bp->b_file_offset == range_base &&
-                    bp->b_buffer_length == range_length) {
+        /* get tree root */
+        pag = xfs_perag_get(btp->bt_mount,
+                                xfs_daddr_to_agno(btp->bt_mount, ioff));
+
+        /* walk tree */
+        spin_lock(&pag->pag_buf_lock);
+        rbp = &pag->pag_buf_tree.rb_node;
+        parent = NULL;
+        bp = NULL;
+        while (*rbp) {
+                parent = *rbp;
+                bp = rb_entry(parent, struct xfs_buf, b_rbnode);
+
+                if (range_base < bp->b_file_offset)
+                        rbp = &(*rbp)->rb_left;
+                else if (range_base > bp->b_file_offset)
+                        rbp = &(*rbp)->rb_right;
+                else {
+                        /*
+                         * found a block offset match. If the range doesn't
+                         * match, the only way this is allowed is if the buffer
+                         * in the cache is stale and the transaction that made
+                         * it stale has not yet committed. i.e. we are
+                         * reallocating a busy extent. Skip this buffer and
+                         * continue searching to the right for an exact match.
+                         */
+                        if (bp->b_buffer_length != range_length) {
+                                ASSERT(bp->b_flags & XBF_STALE);
+                                rbp = &(*rbp)->rb_right;
+                                continue;
+                        }
                         atomic_inc(&bp->b_hold);
                         goto found;
                 }
@@ -449,46 +483,42 @@ _xfs_buf_find(
         if (new_bp) {
                 _xfs_buf_initialize(new_bp, btp, range_base,
                                 range_length, flags);
-                new_bp->b_hash = hash;
-                list_add(&new_bp->b_hash_list, &hash->bh_list);
+                rb_link_node(&new_bp->b_rbnode, parent, rbp);
+                rb_insert_color(&new_bp->b_rbnode, &pag->pag_buf_tree);
+                /* the buffer keeps the perag reference until it is freed */
+                new_bp->b_pag = pag;
+                spin_unlock(&pag->pag_buf_lock);
         } else {
                 XFS_STATS_INC(xb_miss_locked);
+                spin_unlock(&pag->pag_buf_lock);
+                xfs_perag_put(pag);
         }
-
-        spin_unlock(&hash->bh_lock);
         return new_bp;
 
 found:
-        spin_unlock(&hash->bh_lock);
+        spin_unlock(&pag->pag_buf_lock);
+        xfs_perag_put(pag);
 
-        /* Attempt to get the semaphore without sleeping,
-         * if this does not work then we need to drop the
-         * spinlock and do a hard attempt on the semaphore.
-         */
-        if (down_trylock(&bp->b_sema)) {
+        if (xfs_buf_cond_lock(bp)) {
+                /* failed, so wait for the lock if requested. */
                 if (!(flags & XBF_TRYLOCK)) {
-                        /* wait for buffer ownership */
                         xfs_buf_lock(bp);
                         XFS_STATS_INC(xb_get_locked_waited);
                 } else {
-                        /* We asked for a trylock and failed, no need
-                         * to look at file offset and length here, we
-                         * know that this buffer at least overlaps our
-                         * buffer and is locked, therefore our buffer
-                         * either does not exist, or is this buffer.
-                         */
                         xfs_buf_rele(bp);
                         XFS_STATS_INC(xb_busy_locked);
                         return NULL;
                 }
-        } else {
-                /* trylock worked */
-                XB_SET_OWNER(bp);
         }
 
+        /*
+         * 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_);
@@ -509,7 +539,7 @@ 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))
@@ -517,7 +547,7 @@ 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 {
@@ -526,14 +556,11 @@ 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)) {
-                        printk(KERN_WARNING "%s: failed to map pages\n",
-                                        __func__);
+                        xfs_warn(target->bt_mount,
+                                "%s: failed to map pages\n", __func__);
                         goto no_buffer;
                 }
         }
@@ -625,17 +652,47 @@ void
 xfs_buf_readahead(
         xfs_buftarg_t           *target,
         xfs_off_t               ioff,
-        size_t                  isize,
-        xfs_buf_flags_t         flags)
+        size_t                  isize)
 {
-        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;
 
-        flags |= (XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD);
-        xfs_buf_read(target, ioff, isize, flags);
+        xfs_buf_read(target, ioff, isize,
+                     XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD|XBF_DONT_BLOCK);
+}
+
+/*
+ * Read an uncached buffer from disk. Allocates and returns a locked
+ * buffer containing the disk contents or nothing.
+ */
+struct xfs_buf *
+xfs_buf_read_uncached(
+        struct xfs_mount        *mp,
+        struct xfs_buftarg      *target,
+        xfs_daddr_t             daddr,
+        size_t                  length,
+        int                     flags)
+{
+        xfs_buf_t               *bp;
+        int                     error;
+
+        bp = xfs_buf_get_uncached(target, length, flags);
+        if (!bp)
+                return NULL;
+
+        /* set up the buffer for a read IO */
+        xfs_buf_lock(bp);
+        XFS_BUF_SET_ADDR(bp, daddr);
+        XFS_BUF_READ(bp);
+        XFS_BUF_BUSY(bp);
+
+        xfsbdstrat(mp, bp);
+        error = xfs_buf_iowait(bp);
+        if (error || bp->b_error) {
+                xfs_buf_relse(bp);
+                return NULL;
+        }
+        return bp;
 }
 
 xfs_buf_t *
@@ -651,6 +708,27 @@ xfs_buf_get_empty(
         return bp;
 }
 
+/*
+ * Return a buffer allocated as an empty buffer and associated to external
+ * memory via xfs_buf_associate_memory() back to it's empty state.
+ */
+void
+xfs_buf_set_empty(
+        struct xfs_buf          *bp,
+        size_t                  len)
+{
+        if (bp->b_pages)
+                _xfs_buf_free_pages(bp);
+
+        bp->b_pages = NULL;
+        bp->b_page_count = 0;
+        bp->b_addr = NULL;
+        bp->b_file_offset = 0;
+        bp->b_buffer_length = bp->b_count_desired = len;
+        bp->b_bn = XFS_BUF_DADDR_NULL;
+        bp->b_flags &= ~XBF_MAPPED;
+}
+
 static inline struct page *
 mem_to_page(
         void                    *addr)
@@ -675,10 +753,10 @@ 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)
@@ -695,21 +773,21 @@ 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;
 }
 
 xfs_buf_t *
-xfs_buf_get_noaddr(
+xfs_buf_get_uncached(
+        struct xfs_buftarg      *target,
         size_t                  len,
-        xfs_buftarg_t           *target)
+        int                     flags)
 {
         unsigned long           page_count = PAGE_ALIGN(len) >> PAGE_SHIFT;
         int                     error, i;
@@ -725,7 +803,7 @@ xfs_buf_get_noaddr(
                 goto fail_free_buf;
 
         for (i = 0; i < page_count; i++) {
-                bp->b_pages[i] = alloc_page(GFP_KERNEL);
+                bp->b_pages[i] = alloc_page(xb_to_gfp(flags));
                 if (!bp->b_pages[i])
                         goto fail_free_mem;
         }
@@ -733,14 +811,14 @@ xfs_buf_get_noaddr(
 
         error = _xfs_buf_map_pages(bp, XBF_MAPPED);
         if (unlikely(error)) {
-                printk(KERN_WARNING "%s: failed to map pages\n",
-                                __func__);
+                xfs_warn(target->bt_mount,
+                        "%s: failed to map pages\n", __func__);
                 goto fail_free_mem;
         }
 
         xfs_buf_unlock(bp);
 
-        trace_xfs_buf_get_noaddr(bp, _RET_IP_);
+        trace_xfs_buf_get_uncached(bp, _RET_IP_);
         return bp;
 
  fail_free_mem:
@@ -774,29 +852,32 @@ void
 xfs_buf_rele(
         xfs_buf_t               *bp)
 {
-        xfs_bufhash_t           *hash = bp->b_hash;
+        struct xfs_perag        *pag = bp->b_pag;
 
         trace_xfs_buf_rele(bp, _RET_IP_);
 
-        if (unlikely(!hash)) {
-                ASSERT(!bp->b_relse);
+        if (!pag) {
+                ASSERT(list_empty(&bp->b_lru));
+                ASSERT(RB_EMPTY_NODE(&bp->b_rbnode));
                 if (atomic_dec_and_test(&bp->b_hold))
                         xfs_buf_free(bp);
                 return;
         }
 
+        ASSERT(!RB_EMPTY_NODE(&bp->b_rbnode));
+
         ASSERT(atomic_read(&bp->b_hold) > 0);
-        if (atomic_dec_and_lock(&bp->b_hold, &hash->bh_lock)) {
-                if (bp->b_relse) {
-                        atomic_inc(&bp->b_hold);
-                        spin_unlock(&hash->bh_lock);
-                        (*(bp->b_relse)) (bp);
-                } else if (bp->b_flags & XBF_FS_MANAGED) {
-                        spin_unlock(&hash->bh_lock);
+        if (atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock)) {
+                if (!(bp->b_flags & XBF_STALE) &&
+                           atomic_read(&bp->b_lru_ref)) {
+                        xfs_buf_lru_add(bp);
+                        spin_unlock(&pag->pag_buf_lock);
                 } else {
+                        xfs_buf_lru_del(bp);
                         ASSERT(!(bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)));
-                        list_del_init(&bp->b_hash_list);
-                        spin_unlock(&hash->bh_lock);
+                        rb_erase(&bp->b_rbnode, &pag->pag_buf_tree);
+                        spin_unlock(&pag->pag_buf_lock);
+                        xfs_perag_put(pag);
                         xfs_buf_free(bp);
                 }
         }
@@ -804,20 +885,15 @@ xfs_buf_rele(
 
 
 /*
- *      Mutual exclusion on buffers.  Locking model:
+ *      Lock a buffer object, if it is not already locked.
  *
- *      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.
+ *      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
+ *      pinned, we know that the log has not been pushed to disk and hence it
+ *      will still be locked.  Rather than continuing to have trylock attempts
+ *      fail until someone else pushes the log, push it ourselves before
+ *      returning.  This means that the xfsaild will not get stuck trying
+ *      to push on stale inode buffers.
  */
 int
 xfs_buf_cond_lock(
@@ -828,6 +904,8 @@ xfs_buf_cond_lock(
         locked = down_trylock(&bp->b_sema) == 0;
         if (locked)
                 XB_SET_OWNER(bp);
+        else if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
+                xfs_log_force(bp->b_target->bt_mount, 0);
 
         trace_xfs_buf_cond_lock(bp, _RET_IP_);
         return locked ? 0 : -EBUSY;
@@ -841,10 +919,7 @@ 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
@@ -859,9 +934,7 @@ xfs_buf_lock(
         trace_xfs_buf_lock(bp, _RET_IP_);
 
         if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
-                xfs_log_force(bp->b_mount, 0);
-        if (atomic_read(&bp->b_io_remaining))
-                blk_run_address_space(bp->b_target->bt_mapping);
+                xfs_log_force(bp->b_target->bt_mount, 0);
         down(&bp->b_sema);
         XB_SET_OWNER(bp);
 
@@ -905,9 +978,7 @@ xfs_buf_wait_unpin(
                 set_current_state(TASK_UNINTERRUPTIBLE);
                 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);
-                schedule();
+                io_schedule();
         }
         remove_wait_queue(&bp->b_waiters, &wait);
         set_current_state(TASK_RUNNING);
@@ -924,19 +995,7 @@ xfs_buf_iodone_work(
         xfs_buf_t               *bp =
                 container_of(work, xfs_buf_t, b_iodone_work);
 
-        /*
-         * We can get an EOPNOTSUPP to ordered writes.  Here we clear the
-         * ordered flag and reissue them.  Because we can't tell the higher
-         * layers directly that they should not issue ordered I/O anymore, they
-         * need to check if the _XFS_BARRIER_FAILED flag was set during I/O completion.
-         */
-        if ((bp->b_error == EOPNOTSUPP) &&
-            (bp->b_flags & (XBF_ORDERED|XBF_ASYNC)) == (XBF_ORDERED|XBF_ASYNC)) {
-                trace_xfs_buf_ordered_retry(bp, _RET_IP_);
-                bp->b_flags &= ~XBF_ORDERED;
-                bp->b_flags |= _XFS_BARRIER_FAILED;
-                xfs_buf_iorequest(bp);
-        } else if (bp->b_iodone)
+        if (bp->b_iodone)
                 (*(bp->b_iodone))(bp);
         else if (bp->b_flags & XBF_ASYNC)
                 xfs_buf_relse(bp);
@@ -982,7 +1041,6 @@ xfs_bwrite(
 {
         int                     error;
 
-        bp->b_mount = mp;
         bp->b_flags |= XBF_WRITE;
         bp->b_flags &= ~(XBF_ASYNC | XBF_READ);
 
@@ -1003,8 +1061,6 @@ xfs_bdwrite(
 {
         trace_xfs_buf_bdwrite(bp, _RET_IP_);
 
-        bp->b_mount = mp;
-
         bp->b_flags &= ~XBF_READ;
         bp->b_flags |= (XBF_DELWRI | XBF_ASYNC);
 
@@ -1013,7 +1069,7 @@ xfs_bdwrite(
 
 /*
  * Called when we want to stop a buffer from getting written or read.
- * We attach the EIO error, muck with its flags, and call biodone
+ * We attach the EIO error, muck with its flags, and call xfs_buf_ioend
  * so that the proper iodone callbacks get called.
  */
 STATIC int
@@ -1030,21 +1086,21 @@ xfs_bioerror(
         XFS_BUF_ERROR(bp, EIO);
 
         /*
-         * We're calling biodone, so delete XBF_DONE flag.
+         * We're calling xfs_buf_ioend, so delete XBF_DONE flag.
          */
         XFS_BUF_UNREAD(bp);
         XFS_BUF_UNDELAYWRITE(bp);
         XFS_BUF_UNDONE(bp);
         XFS_BUF_STALE(bp);
 
-        xfs_biodone(bp);
+        xfs_buf_ioend(bp, 0);
 
         return EIO;
 }
 
 /*
  * Same as xfs_bioerror, except that we are releasing the buffer
- * here ourselves, and avoiding the biodone call.
+ * here ourselves, and avoiding the xfs_buf_ioend call.
  * This is meant for userdata errors; metadata bufs come with
  * iodone functions attached, so that we can track down errors.
  */
@@ -1093,7 +1149,7 @@ int
 xfs_bdstrat_cb(
         struct xfs_buf  *bp)
 {
-        if (XFS_FORCED_SHUTDOWN(bp->b_mount)) {
+        if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
                 trace_xfs_bdstrat_shut(bp, _RET_IP_);
                 /*
                  * Metadata write that didn't get logged but
@@ -1134,10 +1190,8 @@ _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
@@ -1146,35 +1200,12 @@ 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);
 }
@@ -1188,14 +1219,13 @@ _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;
 
         if (bp->b_flags & XBF_ORDERED) {
                 ASSERT(!(bp->b_flags & XBF_READ));
-                rw = WRITE_BARRIER;
+                rw = WRITE_FLUSH_FUA;
         } else if (bp->b_flags & XBF_LOG_BUFFER) {
                 ASSERT(!(bp->b_flags & XBF_READ_AHEAD));
                 bp->b_flags &= ~_XBF_RUN_QUEUES;
@@ -1209,29 +1239,6 @@ _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);
@@ -1245,8 +1252,9 @@ 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;
@@ -1261,7 +1269,6 @@ 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,
@@ -1271,18 +1278,7 @@ 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);
         }
 }
@@ -1327,8 +1323,6 @@ 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);
         wait_for_completion(&bp->b_iowait);
 
         trace_xfs_buf_iowait_done(bp, _RET_IP_);
@@ -1346,8 +1340,8 @@ 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));
 }
 
 /*
@@ -1369,9 +1363,9 @@ 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:
@@ -1394,89 +1388,84 @@ xfs_buf_iomove(
  */
 
 /*
- *      Wait for any bufs with callbacks that have been submitted but
- *      have not yet returned... walk the hash list for the target.
+ * Wait for any bufs with callbacks that have been submitted but have not yet
+ * returned. These buffers will have an elevated hold count, so wait on those
+ * while freeing all the buffers only held by the LRU.
  */
 void
 xfs_wait_buftarg(
-        xfs_buftarg_t   *btp)
+        struct xfs_buftarg      *btp)
 {
-        xfs_buf_t       *bp, *n;
-        xfs_bufhash_t   *hash;
-        uint            i;
-
-        for (i = 0; i < (1 << btp->bt_hashshift); i++) {
-                hash = &btp->bt_hash[i];
-again:
-                spin_lock(&hash->bh_lock);
-                list_for_each_entry_safe(bp, n, &hash->bh_list, b_hash_list) {
-                        ASSERT(btp == bp->b_target);
-                        if (!(bp->b_flags & XBF_FS_MANAGED)) {
-                                spin_unlock(&hash->bh_lock);
-                                /*
-                                 * Catch superblock reference count leaks
-                                 * immediately
-                                 */
-                                BUG_ON(bp->b_bn == 0);
-                                delay(100);
-                                goto again;
-                        }
+        struct xfs_buf          *bp;
+
+restart:
+        spin_lock(&btp->bt_lru_lock);
+        while (!list_empty(&btp->bt_lru)) {
+                bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru);
+                if (atomic_read(&bp->b_hold) > 1) {
+                        spin_unlock(&btp->bt_lru_lock);
+                        delay(100);
+                        goto restart;
                 }
-                spin_unlock(&hash->bh_lock);
+                /*
+                 * clear the LRU reference count so the bufer doesn't get
+                 * ignored in xfs_buf_rele().
+                 */
+                atomic_set(&bp->b_lru_ref, 0);
+                spin_unlock(&btp->bt_lru_lock);
+                xfs_buf_rele(bp);
+                spin_lock(&btp->bt_lru_lock);
         }
+        spin_unlock(&btp->bt_lru_lock);
 }
 
-/*
- *      Allocate buffer hash table for a given target.
- *      For devices containing metadata (i.e. not the log/realtime devices)
- *      we need to allocate a much larger hash table.
- */
-STATIC void
-xfs_alloc_bufhash(
-        xfs_buftarg_t           *btp,
-        int                     external)
+int
+xfs_buftarg_shrink(
+        struct shrinker         *shrink,
+        struct shrink_control   *sc)
 {
-        unsigned int            i;
+        struct xfs_buftarg      *btp = container_of(shrink,
+                                        struct xfs_buftarg, bt_shrinker);
+        struct xfs_buf          *bp;
+        int nr_to_scan = sc->nr_to_scan;
+        LIST_HEAD(dispose);
 
-        btp->bt_hashshift = external ? 3 : 12;  /* 8 or 4096 buckets */
-        btp->bt_hash = kmem_zalloc_large((1 << btp->bt_hashshift) *
-                                         sizeof(xfs_bufhash_t));
-        for (i = 0; i < (1 << btp->bt_hashshift); i++) {
-                spin_lock_init(&btp->bt_hash[i].bh_lock);
-                INIT_LIST_HEAD(&btp->bt_hash[i].bh_list);
-        }
-}
+        if (!nr_to_scan)
+                return btp->bt_lru_nr;
 
-STATIC void
-xfs_free_bufhash(
-        xfs_buftarg_t           *btp)
-{
-        kmem_free_large(btp->bt_hash);
-        btp->bt_hash = NULL;
-}
+        spin_lock(&btp->bt_lru_lock);
+        while (!list_empty(&btp->bt_lru)) {
+                if (nr_to_scan-- <= 0)
+                        break;
 
-/*
- *      buftarg list for delwrite queue processing
- */
-static LIST_HEAD(xfs_buftarg_list);
-static DEFINE_SPINLOCK(xfs_buftarg_lock);
+                bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru);
 
-STATIC void
-xfs_register_buftarg(
-        xfs_buftarg_t           *btp)
-{
-        spin_lock(&xfs_buftarg_lock);
-        list_add(&btp->bt_list, &xfs_buftarg_list);
-        spin_unlock(&xfs_buftarg_lock);
-}
+                /*
+                 * Decrement the b_lru_ref count unless the value is already
+                 * zero. If the value is already zero, we need to reclaim the
+                 * buffer, otherwise it gets another trip through the LRU.
+                 */
+                if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) {
+                        list_move_tail(&bp->b_lru, &btp->bt_lru);
+                        continue;
+                }
 
-STATIC void
-xfs_unregister_buftarg(
-        xfs_buftarg_t           *btp)
-{
-        spin_lock(&xfs_buftarg_lock);
-        list_del(&btp->bt_list);
-        spin_unlock(&xfs_buftarg_lock);
+                /*
+                 * remove the buffer from the LRU now to avoid needing another
+                 * lock round trip inside xfs_buf_rele().
+                 */
+                list_move(&bp->b_lru, &dispose);
+                btp->bt_lru_nr--;
+        }
+        spin_unlock(&btp->bt_lru_lock);
+
+        while (!list_empty(&dispose)) {
+                bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
+                list_del_init(&bp->b_lru);
+                xfs_buf_rele(bp);
+        }
+
+        return btp->bt_lru_nr;
 }
 
 void
@@ -1484,18 +1473,13 @@ xfs_free_buftarg(
         struct xfs_mount        *mp,
         struct xfs_buftarg      *btp)
 {
+        unregister_shrinker(&btp->bt_shrinker);
+
         xfs_flush_buftarg(btp, 1);
         if (mp->m_flags & XFS_MOUNT_BARRIER)
                 xfs_blkdev_issue_flush(btp);
-        xfs_free_bufhash(btp);
-        iput(btp->bt_mapping->host);
 
-        /* Unregister the buftarg first so that we don't get a
-         * wakeup finding a non-existent task
-         */
-        xfs_unregister_buftarg(btp);
         kthread_stop(btp->bt_task);
-
         kmem_free(btp);
 }
 
@@ -1511,21 +1495,12 @@ xfs_setsize_buftarg_flags(
         btp->bt_smask = sectorsize - 1;
 
         if (set_blocksize(btp->bt_bdev, sectorsize)) {
-                printk(KERN_WARNING
-                        "XFS: Cannot set_blocksize to %u on device %s\n",
+                xfs_warn(btp->bt_mount,
+                        "Cannot set_blocksize to %u on device %s\n",
                         sectorsize, XFS_BUFTARG_NAME(btp));
                 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;
 }
 
@@ -1540,7 +1515,7 @@ 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
@@ -1553,62 +1528,22 @@ 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_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)
 {
-        int     error = 0;
-
-        INIT_LIST_HEAD(&btp->bt_list);
         INIT_LIST_HEAD(&btp->bt_delwrite_queue);
         spin_lock_init(&btp->bt_delwrite_lock);
         btp->bt_flags = 0;
         btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd/%s", fsname);
-        if (IS_ERR(btp->bt_task)) {
-                error = PTR_ERR(btp->bt_task);
-                goto out_error;
-        }
-        xfs_register_buftarg(btp);
-out_error:
-        return error;
+        if (IS_ERR(btp->bt_task))
+                return PTR_ERR(btp->bt_task);
+        return 0;
 }
 
 xfs_buftarg_t *
 xfs_alloc_buftarg(
+        struct xfs_mount        *mp,
         struct block_device     *bdev,
         int                     external,
         const char              *fsname)
@@ -1617,15 +1552,22 @@ xfs_alloc_buftarg(
 
         btp = kmem_zalloc(sizeof(*btp), KM_SLEEP);
 
+        btp->bt_mount = mp;
         btp->bt_dev =  bdev->bd_dev;
         btp->bt_bdev = bdev;
-        if (xfs_setsize_buftarg_early(btp, bdev))
+        btp->bt_bdi = blk_get_backing_dev_info(bdev);
+        if (!btp->bt_bdi)
                 goto error;
-        if (xfs_mapping_buftarg(btp, bdev))
+
+        INIT_LIST_HEAD(&btp->bt_lru);
+        spin_lock_init(&btp->bt_lru_lock);
+        if (xfs_setsize_buftarg_early(btp, bdev))
                 goto error;
         if (xfs_alloc_delwrite_queue(btp, fsname))
                 goto error;
-        xfs_alloc_bufhash(btp, external);
+        btp->bt_shrinker.shrink = xfs_buftarg_shrink;
+        btp->bt_shrinker.seeks = DEFAULT_SEEKS;
+        register_shrinker(&btp->bt_shrinker);
         return btp;
 
 error:
@@ -1730,27 +1672,6 @@ xfs_buf_runall_queues(
         flush_workqueue(queue);
 }
 
-STATIC int
-xfsbufd_wakeup(
-        struct shrinker         *shrink,
-        int                     priority,
-        gfp_t                   mask)
-{
-        xfs_buftarg_t           *btp;
-
-        spin_lock(&xfs_buftarg_lock);
-        list_for_each_entry(btp, &xfs_buftarg_list, bt_list) {
-                if (test_bit(XBT_FORCE_SLEEP, &btp->bt_flags))
-                        continue;
-                if (list_empty(&btp->bt_delwrite_queue))
-                        continue;
-                set_bit(XBT_FORCE_FLUSH, &btp->bt_flags);
-                wake_up_process(btp->bt_task);
-        }
-        spin_unlock(&xfs_buftarg_lock);
-        return 0;
-}
-
 /*
  * Move as many buffers as specified to the supplied list
  * idicating if we skipped any buffers to prevent deadlocks.
@@ -1771,7 +1692,6 @@ xfs_buf_delwri_split(
         INIT_LIST_HEAD(list);
         spin_lock(dwlk);
         list_for_each_entry_safe(bp, n, dwq, b_list) {
-                trace_xfs_buf_delwri_split(bp, _RET_IP_);
                 ASSERT(bp->b_flags & XBF_DELWRI);
 
                 if (!XFS_BUF_ISPINNED(bp) && !xfs_buf_cond_lock(bp)) {
@@ -1785,6 +1705,7 @@ xfs_buf_delwri_split(
                                          _XBF_RUN_QUEUES);
                         bp->b_flags |= XBF_WRITE;
                         list_move_tail(&bp->b_list, list);
+                        trace_xfs_buf_delwri_split(bp, _RET_IP_);
                 } else
                         skipped++;
         }
@@ -1838,8 +1759,8 @@ xfsbufd(
         do {
                 long    age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
                 long    tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
-                int     count = 0;
                 struct list_head tmp;
+                struct blk_plug plug;
 
                 if (unlikely(freezing(current))) {
                         set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
@@ -1855,16 +1776,15 @@ xfsbufd(
 
                 xfs_buf_delwri_split(target, &tmp, age);
                 list_sort(NULL, &tmp, xfs_buf_cmp);
+
+                blk_start_plug(&plug);
                 while (!list_empty(&tmp)) {
                         struct xfs_buf *bp;
                         bp = list_first_entry(&tmp, struct xfs_buf, b_list);
                         list_del_init(&bp->b_list);
                         xfs_bdstrat_cb(bp);
-                        count++;
                 }
-                if (count)
-                        blk_run_address_space(target->bt_mapping);
-
+                blk_finish_plug(&plug);
         } while (!kthread_should_stop());
 
         return 0;
@@ -1884,6 +1804,7 @@ xfs_flush_buftarg(
         int             pincount = 0;
         LIST_HEAD(tmp_list);
         LIST_HEAD(wait_list);
+        struct blk_plug plug;
 
         xfs_buf_runall_queues(xfsconvertd_workqueue);
         xfs_buf_runall_queues(xfsdatad_workqueue);
@@ -1898,6 +1819,8 @@ xfs_flush_buftarg(
          * we do that after issuing all the IO.
          */
         list_sort(NULL, &tmp_list, xfs_buf_cmp);
+
+        blk_start_plug(&plug);
         while (!list_empty(&tmp_list)) {
                 bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
                 ASSERT(target == bp->b_target);
@@ -1908,15 +1831,15 @@ xfs_flush_buftarg(
                 }
                 xfs_bdstrat_cb(bp);
         }
+        blk_finish_plug(&plug);
 
         if (wait) {
-                /* Expedite and wait for IO to complete. */
-                blk_run_address_space(target->bt_mapping);
+                /* Wait for IO to complete. */
                 while (!list_empty(&wait_list)) {
                         bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
 
                         list_del_init(&bp->b_list);
-                        xfs_iowait(bp);
+                        xfs_buf_iowait(bp);
                         xfs_buf_relse(bp);
                 }
         }
@@ -1933,19 +1856,19 @@ xfs_buf_init(void)
                 goto out;
 
         xfslogd_workqueue = alloc_workqueue("xfslogd",
-                                        WQ_RESCUER | WQ_HIGHPRI, 1);
+                                        WQ_MEM_RECLAIM | WQ_HIGHPRI, 1);
         if (!xfslogd_workqueue)
                 goto out_free_buf_zone;
 
-        xfsdatad_workqueue = create_workqueue("xfsdatad");
+        xfsdatad_workqueue = alloc_workqueue("xfsdatad", WQ_MEM_RECLAIM, 1);
         if (!xfsdatad_workqueue)
                 goto out_destroy_xfslogd_workqueue;
 
-        xfsconvertd_workqueue = create_workqueue("xfsconvertd");
+        xfsconvertd_workqueue = alloc_workqueue("xfsconvertd",
+                                                WQ_MEM_RECLAIM, 1);
         if (!xfsconvertd_workqueue)
                 goto out_destroy_xfsdatad_workqueue;
 
-        register_shrinker(&xfs_buf_shake);
         return 0;
 
  out_destroy_xfsdatad_workqueue:
@@ -1961,7 +1884,6 @@ xfs_buf_init(void)
 void
 xfs_buf_terminate(void)
 {
-        unregister_shrinker(&xfs_buf_shake);
         destroy_workqueue(xfsconvertd_workqueue);
         destroy_workqueue(xfsdatad_workqueue);
         destroy_workqueue(xfslogd_workqueue);