diff --git a/fs/btrfs/compat.h b/fs/btrfs/compat.h
index cd6598b..dd1defd 100644
--- a/fs/btrfs/compat.h
+++ b/fs/btrfs/compat.h
@@ -21,4 +21,11 @@
 }
 #endif
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
+# define  __pagevec_lru_add_file __pagevec_lru_add
+# define open_bdev_exclusive open_bdev_excl
+# define close_bdev_exclusive(bdev, mode) close_bdev_excl(bdev)
+#endif
+
+
 #endif /* _COMPAT_H_ */
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index bfd1512..df05f51 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -419,7 +419,7 @@
 		/* open coding of lru_cache_add, also not exported */
 		page_cache_get(page);
 		if (!pagevec_add(&pvec, page))
-			__pagevec_lru_add(&pvec);
+			__pagevec_lru_add_file(&pvec);
 
 		end = last_offset + PAGE_CACHE_SIZE - 1;
 		/*
@@ -475,7 +475,7 @@
 		last_offset += PAGE_CACHE_SIZE;
 	}
 	if (pagevec_count(&pvec))
-		__pagevec_lru_add(&pvec);
+		__pagevec_lru_add_file(&pvec);
 	return 0;
 }
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index ee73efe..62d4970 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -28,6 +28,7 @@
 #include "volumes.h"
 #include "locking.h"
 #include "ref-cache.h"
+#include "compat.h"
 
 #define PENDING_EXTENT_INSERT 0
 #define PENDING_EXTENT_DELETE 1
@@ -899,6 +900,17 @@
 	return ret;
 }
 
+static void btrfs_issue_discard(struct block_device *bdev,
+				u64 start, u64 len)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28)
+	blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL);
+#else
+	blkdev_issue_discard(bdev, start >> 9, len >> 9);
+#endif
+}
+
+
 static int noinline free_extents(struct btrfs_trans_handle *trans,
 				 struct btrfs_root *extent_root,
 				 struct list_head *del_list)
@@ -1108,6 +1120,7 @@
 			BUG_ON(ret);
 
 #ifdef BIO_RW_DISCARD
+			map_length = tmp->num_bytes;
 			ret = btrfs_map_block(&info->mapping_tree, READ,
 					      tmp->bytenr, &map_length, &multi,
 					      0);
@@ -1115,16 +1128,16 @@
 				struct btrfs_bio_stripe *stripe;
 				int i;
 
-				stripe = multi->stripe;
+				stripe = multi->stripes;
 
 				if (map_length > tmp->num_bytes)
 					map_length = tmp->num_bytes;
 
 				for (i = 0; i < multi->num_stripes;
 				     i++, stripe++)
-					blkdev_issue_discard(stripe->dev->bdev,
-							stripe->physical >> 9,
-							map_length >> 9);
+					btrfs_issue_discard(stripe->dev->bdev,
+							    stripe->physical,
+							    map_length);
 				kfree(multi);
 			}
 #endif
@@ -2498,9 +2511,9 @@
 				map_length = num_bytes;
 
 			for (i = 0; i < multi->num_stripes; i++, stripe++) {
-				blkdev_issue_discard(stripe->dev->bdev,
-						     stripe->physical >> 9,
-						     map_length >> 9);
+				btrfs_issue_discard(stripe->dev->bdev,
+						    stripe->physical,
+						     map_length);
 			}
 			kfree(multi);
 		}
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a0f3804..3a65c10 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2639,14 +2639,14 @@
 			/* open coding of lru_cache_add, also not exported */
 			page_cache_get(page);
 			if (!pagevec_add(&pvec, page))
-				__pagevec_lru_add(&pvec);
+				__pagevec_lru_add_file(&pvec);
 			__extent_read_full_page(tree, page, get_extent,
 						&bio, 0, &bio_flags);
 		}
 		page_cache_release(page);
 	}
 	if (pagevec_count(&pvec))
-		__pagevec_lru_add(&pvec);
+		__pagevec_lru_add_file(&pvec);
 	BUG_ON(!list_empty(pages));
 	if (bio)
 		submit_one_bio(READ, bio, 0, bio_flags);
diff --git a/fs/btrfs/version.sh b/fs/btrfs/version.sh
index 0f57f24..1ca1952 100644
--- a/fs/btrfs/version.sh
+++ b/fs/btrfs/version.sh
@@ -8,24 +8,24 @@
  
 v="v0.16"
 
-which hg > /dev/null
-if [ -d .hg ] && [ $? == 0 ]; then
-	last=$(hg tags | grep -m1 -o '^v[0-9.]\+')
-	 
-	# now check if the repo has commits since then...
-	if [[ $(hg id -t) == $last || \
-	    $(hg di -r "$last:." | awk '/^diff/{print $NF}' | sort -u) == .hgtags ]]
-	then
-	    # check if it's dirty
-	    if [[ $(hg id | cut -d' ' -f1) == *+ ]]; then
-		v=$last+
-	    else
-		v=$last
+which git &> /dev/null
+if [ $? == 0 ]; then
+    git branch >& /dev/null
+    if [ $? == 0 ]; then
+	    if head=`git rev-parse --verify HEAD 2>/dev/null`; then
+		if tag=`git describe --tags 2>/dev/null`; then
+		    v="$tag"
+		fi
+
+		# Are there uncommitted changes?
+		git update-index --refresh --unmerged > /dev/null
+		if git diff-index --name-only HEAD | \
+		    grep -v "^scripts/package" \
+		    | read dummy; then
+		    v="$v"-dirty
+		fi
 	    fi
-	else
-	    # includes dirty flag
-	    v=$last+$(hg id -i)
-	fi
+    fi
 fi
  
 echo "#ifndef __BUILD_VERSION" > .build-version.h
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ecf0633..c3ee63f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -85,7 +85,7 @@
 			dev = list_entry(fs_devices->devices.next,
 					 struct btrfs_device, dev_list);
 			if (dev->bdev) {
-				close_bdev_excl(dev->bdev);
+				close_bdev_exclusive(dev->bdev, dev->mode);
 				fs_devices->open_devices--;
 			}
 			fs_devices->num_devices--;
@@ -317,7 +317,7 @@
 			continue;
 
 		if (device->bdev) {
-			close_bdev_excl(device->bdev);
+			close_bdev_exclusive(device->bdev, device->mode);
 			device->bdev = NULL;
 			fs_devices->open_devices--;
 		}
@@ -356,7 +356,7 @@
 	list_for_each(cur, &fs_devices->devices) {
 		device = list_entry(cur, struct btrfs_device, dev_list);
 		if (device->bdev) {
-			close_bdev_excl(device->bdev);
+			close_bdev_exclusive(device->bdev, device->mode);
 			fs_devices->open_devices--;
 		}
 		if (device->writeable) {
@@ -391,7 +391,8 @@
 	return ret;
 }
 
-int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices, void *holder)
+int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
+			 int flags, void *holder)
 {
 	struct block_device *bdev;
 	struct list_head *head = &fs_devices->devices;
@@ -413,7 +414,7 @@
 		if (!device->name)
 			continue;
 
-		bdev = open_bdev_excl(device->name, MS_RDONLY, holder);
+		bdev = open_bdev_exclusive(device->name, flags, holder);
 		if (IS_ERR(bdev)) {
 			printk("open %s failed\n", device->name);
 			goto error;
@@ -453,6 +454,8 @@
 
 		device->bdev = bdev;
 		device->in_fs_metadata = 0;
+		device->mode = flags;
+
 		fs_devices->open_devices++;
 		if (device->writeable) {
 			fs_devices->rw_devices++;
@@ -464,7 +467,7 @@
 error_brelse:
 		brelse(bh);
 error_close:
-		close_bdev_excl(bdev);
+		close_bdev_exclusive(bdev, MS_RDONLY);
 error:
 		continue;
 	}
@@ -496,7 +499,7 @@
 			ret = 0;
 		}
 	} else {
-		ret = __btrfs_open_devices(fs_devices, holder);
+		ret = __btrfs_open_devices(fs_devices, flags, holder);
 	}
 	mutex_unlock(&uuid_mutex);
 	return ret;
@@ -514,7 +517,7 @@
 
 	mutex_lock(&uuid_mutex);
 
-	bdev = open_bdev_excl(path, flags, holder);
+	bdev = open_bdev_exclusive(path, flags, holder);
 
 	if (IS_ERR(bdev)) {
 		ret = PTR_ERR(bdev);
@@ -551,7 +554,7 @@
 error_brelse:
 	brelse(bh);
 error_close:
-	close_bdev_excl(bdev);
+	close_bdev_exclusive(bdev, flags);
 error:
 	mutex_unlock(&uuid_mutex);
 	return ret;
@@ -1003,7 +1006,7 @@
 			goto out;
 		}
 	} else {
-		bdev = open_bdev_excl(device_path, MS_RDONLY,
+		bdev = open_bdev_exclusive(device_path, MS_RDONLY,
 				      root->fs_info->bdev_holder);
 		if (IS_ERR(bdev)) {
 			ret = PTR_ERR(bdev);
@@ -1073,10 +1076,10 @@
 		BUG_ON(device->writeable);
 		brelse(bh);
 		if (bdev)
-			close_bdev_excl(bdev);
+			close_bdev_exclusive(bdev, MS_RDONLY);
 
 		if (device->bdev) {
-			close_bdev_excl(device->bdev);
+			close_bdev_exclusive(device->bdev, device->mode);
 			device->bdev = NULL;
 			device->fs_devices->open_devices--;
 		}
@@ -1112,11 +1115,11 @@
 
 	if (device->bdev) {
 		/* one close for the device struct or super_block */
-		close_bdev_excl(device->bdev);
+		close_bdev_exclusive(device->bdev, device->mode);
 	}
 	if (bdev) {
 		/* one close for us */
-		close_bdev_excl(bdev);
+		close_bdev_exclusive(bdev, MS_RDONLY);
 	}
 	kfree(device->name);
 	kfree(device);
@@ -1127,7 +1130,7 @@
 	brelse(bh);
 error_close:
 	if (bdev)
-		close_bdev_excl(bdev);
+		close_bdev_exclusive(bdev, MS_RDONLY);
 out:
 	mutex_unlock(&root->fs_info->volume_mutex);
 	mutex_unlock(&uuid_mutex);
@@ -1272,7 +1275,7 @@
 	if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
 		return -EINVAL;
 
-	bdev = open_bdev_excl(device_path, 0, root->fs_info->bdev_holder);
+	bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
 	if (!bdev) {
 		return -EIO;
 	}
@@ -1331,6 +1334,7 @@
 	device->dev_root = root->fs_info->dev_root;
 	device->bdev = bdev;
 	device->in_fs_metadata = 1;
+	device->mode = 0;
 	set_blocksize(device->bdev, 4096);
 
 	if (seeding_dev) {
@@ -1379,7 +1383,7 @@
 	mutex_unlock(&root->fs_info->volume_mutex);
 	return ret;
 error:
-	close_bdev_excl(bdev);
+	close_bdev_exclusive(bdev, 0);
 	if (seeding_dev) {
 		mutex_unlock(&uuid_mutex);
 		up_write(&sb->s_umount);
@@ -2907,7 +2911,8 @@
 		goto out;
 	}
 
-	ret = __btrfs_open_devices(fs_devices, root->fs_info->bdev_holder);
+	ret = __btrfs_open_devices(fs_devices, MS_RDONLY,
+				   root->fs_info->bdev_holder);
 	if (ret)
 		goto out;
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 1f6f25a..9b41e4d 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -42,6 +42,9 @@
 
 	struct block_device *bdev;
 
+	/* the mode sent to open_bdev_exclusive */
+	fmode_t mode;
+
 	char *name;
 
 	/* the internal btrfs device id */