1 files changed, 120 insertions, 99 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index f3ccaec..ba53128 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -188,8 +188,8 @@ _xfs_buf_initialize(
 	atomic_set(&bp->b_hold, 1);
 	init_completion(&bp->b_iowait);
 	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;
@@ -262,8 +262,6 @@ xfs_buf_free(
 {
 	trace_xfs_buf_free(bp, _RET_IP_);
 
-	ASSERT(list_empty(&bp->b_hash_list));
-
 	if (bp->b_flags & (_XBF_PAGE_CACHE|_XBF_PAGES)) {
 		uint		i;
 
@@ -422,8 +420,10 @@ _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 +432,37 @@ _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;
 		}
@@ -449,17 +472,21 @@ _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
@@ -625,8 +652,7 @@ 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;
 
@@ -634,8 +660,42 @@ xfs_buf_readahead(
 	if (bdi_read_congested(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 *
@@ -707,9 +767,10 @@ xfs_buf_associate_memory(
 }
 
 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 +786,7 @@ 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;
 	}
@@ -740,7 +801,7 @@ xfs_buf_get_noaddr(
 
 	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 +835,30 @@ 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)) {
+	if (!pag) {
 		ASSERT(!bp->b_relse);
+		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 (atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_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);
+			spin_unlock(&pag->pag_buf_lock);
+			bp->b_relse(bp);
 		} else {
 			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);
 		}
 	}
@@ -859,7 +921,7 @@ 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);
+		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);
 	down(&bp->b_sema);
@@ -970,7 +1032,6 @@ xfs_bwrite(
 {
 	int			error;
 
-	bp->b_mount = mp;
 	bp->b_flags |= XBF_WRITE;
 	bp->b_flags &= ~(XBF_ASYNC | XBF_READ);
 
@@ -991,8 +1052,6 @@ 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);
 
@@ -1001,7 +1060,7 @@ 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
@@ -1018,21 +1077,21 @@ 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.
  */
@@ -1081,7 +1140,7 @@ 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
@@ -1387,62 +1446,24 @@ xfs_buf_iomove(
  */
 void
 xfs_wait_buftarg(
-	xfs_buftarg_t	*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;
-			}
-		}
-		spin_unlock(&hash->bh_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)
+	struct xfs_buftarg	*btp)
 {
-	unsigned int		i;
+	struct xfs_perag	*pag;
+	uint			i;
 
-	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);
+	for (i = 0; i < btp->bt_mount->m_sb.sb_agcount; i++) {
+		pag = xfs_perag_get(btp->bt_mount, i);
+		spin_lock(&pag->pag_buf_lock);
+		while (rb_first(&pag->pag_buf_tree)) {
+			spin_unlock(&pag->pag_buf_lock);
+			delay(100);
+			spin_lock(&pag->pag_buf_lock);
+		}
+		spin_unlock(&pag->pag_buf_lock);
+		xfs_perag_put(pag);
 	}
 }
 
-STATIC void
-xfs_free_bufhash(
-	xfs_buftarg_t		*btp)
-{
-	kmem_free_large(btp->bt_hash);
-	btp->bt_hash = NULL;
-}
-
 /*
  *	buftarg list for delwrite queue processing
  */
@@ -1475,7 +1496,6 @@ xfs_free_buftarg(
 	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
@@ -1597,6 +1617,7 @@ out_error:
 
 xfs_buftarg_t *
 xfs_alloc_buftarg(
+	struct xfs_mount	*mp,
 	struct block_device	*bdev,
 	int			external,
 	const char		*fsname)
@@ -1605,6 +1626,7 @@ 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))
@@ -1613,7 +1635,6 @@ xfs_alloc_buftarg(
 		goto error;
 	if (xfs_alloc_delwrite_queue(btp, fsname))
 		goto error;
-	xfs_alloc_bufhash(btp, external);
 	return btp;
 
 error:
@@ -1904,7 +1925,7 @@ xfs_flush_buftarg(
 			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);
 		}
 	}