Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs updates from Chris Mason:
 "This includes a fairly large change from Josef around data writeback
  completion.  Before, the writeback wasn't completed until the metadata
  insertions for the extent were done, and this made for fairly large
  latency spikes on the last page of each ordered extent.

  We already had a separate mechanism for tracking pending metadata
  insertions, so Josef just needed to tweak things a little to end
  writeback earlier on the page.  Overall it makes us much friendly to
  memory reclaim and lowers latencies quite a lot for synchronous IO.

  Jan Schmidt has finished some background work required to track btree
  blocks as they go through changes in ownership.  It's the missing
  piece he needed for both btrfs send/receive and subvolume quotas.
  Neither of those are ready yet, but the new tracking code is included
  here.  Most of the time, the new code is off.  It is only used by
  scrub and other backref walkers.

  Stefan Behrens has added io failure tracking.  This includes counters
  for which drives are causing the most trouble so the admin (or an
  automated tool) can choose to kick them out.  We're tracking IO
  errors, crc errors, and generation checks we do on each metadata
  block.

  RAID5/6 did miss the cut this time because I'm having trouble with
  corruptions.  I'll nail it down next week and post as a beta testing
  before 3.6"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (58 commits)
  Btrfs: fix tree mod log rewinded level and rewinding of moved keys
  Btrfs: fix tree mod log del_ptr
  Btrfs: add tree_mod_dont_log helper
  Btrfs: add missing spin_lock for insertion into tree mod log
  Btrfs: add inodes before dropping the extent lock in find_all_leafs
  Btrfs: use delayed ref sequence numbers for all fs-tree updates
  Btrfs: fix false positive in check-integrity on unmount
  Btrfs: fix runtime warning in check-integrity check data mode
  Btrfs: set ioprio of scrub readahead to idle
  Btrfs: fix return code in drop_objectid_items
  Btrfs: check to see if the inode is in the log before fsyncing
  Btrfs: return value of btrfs_read_buffer is checked correctly
  Btrfs: read device stats on mount, write modified ones during commit
  Btrfs: add ioctl to get and reset the device stats
  Btrfs: add device counters for detected IO and checksum errors
  btrfs: Drop unused function btrfs_abort_devices()
  Btrfs: fix the same inode id problem when doing auto defragment
  Btrfs: fall back to non-inline if we don't have enough space
  Btrfs: fix how we deal with the orphan block rsv
  Btrfs: convert the inode bit field to use the actual bit operations
  ...

1 files changed, 436 insertions, 148 deletions

diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index c053e90f2006..9cebb1fd6a3c 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -103,8 +103,6 @@
 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
 							 * excluding " [...]" */
-#define BTRFSIC_BLOCK_SIZE PAGE_SIZE
-
 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 
 /*
@@ -210,8 +208,9 @@ struct btrfsic_block_data_ctx {
 	u64 dev_bytenr;		/* physical bytenr on device */
 	u32 len;
 	struct btrfsic_dev_state *dev;
-	char *data;
-	struct buffer_head *bh;	/* do not use if set to NULL */
+	char **datav;
+	struct page **pagev;
+	void *mem_to_free;
 };
 
 /* This structure is used to implement recursion without occupying
@@ -243,6 +242,8 @@ struct btrfsic_state {
 	struct btrfs_root *root;
 	u64 max_superblock_generation;
 	struct btrfsic_block *latest_superblock;
+	u32 metablock_size;
+	u32 datablock_size;
 };
 
 static void btrfsic_block_init(struct btrfsic_block *b);
@@ -290,8 +291,10 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 static int btrfsic_process_metablock(struct btrfsic_state *state,
 				     struct btrfsic_block *block,
 				     struct btrfsic_block_data_ctx *block_ctx,
-				     struct btrfs_header *hdr,
 				     int limit_nesting, int force_iodone_flag);
+static void btrfsic_read_from_block_data(
+	struct btrfsic_block_data_ctx *block_ctx,
+	void *dst, u32 offset, size_t len);
 static int btrfsic_create_link_to_next_block(
 		struct btrfsic_state *state,
 		struct btrfsic_block *block,
@@ -318,12 +321,13 @@ static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 static int btrfsic_read_block(struct btrfsic_state *state,
 			      struct btrfsic_block_data_ctx *block_ctx);
 static void btrfsic_dump_database(struct btrfsic_state *state);
+static void btrfsic_complete_bio_end_io(struct bio *bio, int err);
 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
-				     const u8 *data, unsigned int size);
+				     char **datav, unsigned int num_pages);
 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
-					  u64 dev_bytenr, u8 *mapped_data,
-					  unsigned int len, struct bio *bio,
-					  int *bio_is_patched,
+					  u64 dev_bytenr, char **mapped_datav,
+					  unsigned int num_pages,
+					  struct bio *bio, int *bio_is_patched,
 					  struct buffer_head *bh,
 					  int submit_bio_bh_rw);
 static int btrfsic_process_written_superblock(
@@ -375,7 +379,7 @@ static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 					   u64 bytenr,
 					   struct btrfsic_dev_state *dev_state,
-					   u64 dev_bytenr, char *data);
+					   u64 dev_bytenr);
 
 static struct mutex btrfsic_mutex;
 static int btrfsic_is_initialized;
@@ -651,7 +655,7 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 	int pass;
 
 	BUG_ON(NULL == state);
-	selected_super = kmalloc(sizeof(*selected_super), GFP_NOFS);
+	selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 	if (NULL == selected_super) {
 		printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 		return -1;
@@ -718,7 +722,7 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 
 		num_copies =
 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
-				     next_bytenr, PAGE_SIZE);
+				     next_bytenr, state->metablock_size);
 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 			       (unsigned long long)next_bytenr, num_copies);
@@ -727,9 +731,9 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 			struct btrfsic_block *next_block;
 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
 			struct btrfsic_block_link *l;
-			struct btrfs_header *hdr;
 
-			ret = btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
+			ret = btrfsic_map_block(state, next_bytenr,
+						state->metablock_size,
 						&tmp_next_block_ctx,
 						mirror_num);
 			if (ret) {
@@ -758,7 +762,7 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 			BUG_ON(NULL == l);
 
 			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
-			if (ret < (int)BTRFSIC_BLOCK_SIZE) {
+			if (ret < (int)PAGE_CACHE_SIZE) {
 				printk(KERN_INFO
 				       "btrfsic: read @logical %llu failed!\n",
 				       (unsigned long long)
@@ -768,11 +772,9 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 				return -1;
 			}
 
-			hdr = (struct btrfs_header *)tmp_next_block_ctx.data;
 			ret = btrfsic_process_metablock(state,
 							next_block,
 							&tmp_next_block_ctx,
-							hdr,
 							BTRFS_MAX_LEVEL + 3, 1);
 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
 		}
@@ -799,7 +801,10 @@ static int btrfsic_process_superblock_dev_mirror(
 
 	/* super block bytenr is always the unmapped device bytenr */
 	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
-	bh = __bread(superblock_bdev, dev_bytenr / 4096, 4096);
+	if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
+		return -1;
+	bh = __bread(superblock_bdev, dev_bytenr / 4096,
+		     BTRFS_SUPER_INFO_SIZE);
 	if (NULL == bh)
 		return -1;
 	super_tmp = (struct btrfs_super_block *)
@@ -808,7 +813,10 @@ static int btrfsic_process_superblock_dev_mirror(
 	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 	    strncmp((char *)(&(super_tmp->magic)), BTRFS_MAGIC,
 		    sizeof(super_tmp->magic)) ||
-	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE)) {
+	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
+	    btrfs_super_nodesize(super_tmp) != state->metablock_size ||
+	    btrfs_super_leafsize(super_tmp) != state->metablock_size ||
+	    btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 		brelse(bh);
 		return 0;
 	}
@@ -893,7 +901,7 @@ static int btrfsic_process_superblock_dev_mirror(
 
 		num_copies =
 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
-				     next_bytenr, PAGE_SIZE);
+				     next_bytenr, state->metablock_size);
 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 			       (unsigned long long)next_bytenr, num_copies);
@@ -902,7 +910,8 @@ static int btrfsic_process_superblock_dev_mirror(
 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
 			struct btrfsic_block_link *l;
 
-			if (btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
+			if (btrfsic_map_block(state, next_bytenr,
+					      state->metablock_size,
 					      &tmp_next_block_ctx,
 					      mirror_num)) {
 				printk(KERN_INFO "btrfsic: btrfsic_map_block("
@@ -966,13 +975,15 @@ static int btrfsic_process_metablock(
 		struct btrfsic_state *state,
 		struct btrfsic_block *const first_block,
 		struct btrfsic_block_data_ctx *const first_block_ctx,
-		struct btrfs_header *const first_hdr,
 		int first_limit_nesting, int force_iodone_flag)
 {
 	struct btrfsic_stack_frame initial_stack_frame = { 0 };
 	struct btrfsic_stack_frame *sf;
 	struct btrfsic_stack_frame *next_stack;
+	struct btrfs_header *const first_hdr =
+		(struct btrfs_header *)first_block_ctx->datav[0];
 
+	BUG_ON(!first_hdr);
 	sf = &initial_stack_frame;
 	sf->error = 0;
 	sf->i = -1;
@@ -1012,21 +1023,47 @@ continue_with_current_leaf_stack_frame:
 		}
 
 		if (sf->i < sf->nr) {
-			struct btrfs_item *disk_item = leafhdr->items + sf->i;
-			struct btrfs_disk_key *disk_key = &disk_item->key;
+			struct btrfs_item disk_item;
+			u32 disk_item_offset =
+				(uintptr_t)(leafhdr->items + sf->i) -
+				(uintptr_t)leafhdr;
+			struct btrfs_disk_key *disk_key;
 			u8 type;
-			const u32 item_offset = le32_to_cpu(disk_item->offset);
+			u32 item_offset;
 
+			if (disk_item_offset + sizeof(struct btrfs_item) >
+			    sf->block_ctx->len) {
+leaf_item_out_of_bounce_error:
+				printk(KERN_INFO
+				       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
+				       sf->block_ctx->start,
+				       sf->block_ctx->dev->name);
+				goto one_stack_frame_backwards;
+			}
+			btrfsic_read_from_block_data(sf->block_ctx,
+						     &disk_item,
+						     disk_item_offset,
+						     sizeof(struct btrfs_item));
+			item_offset = le32_to_cpu(disk_item.offset);
+			disk_key = &disk_item.key;
 			type = disk_key->type;
 
 			if (BTRFS_ROOT_ITEM_KEY == type) {
-				const struct btrfs_root_item *const root_item =
-				    (struct btrfs_root_item *)
-				    (sf->block_ctx->data +
-				     offsetof(struct btrfs_leaf, items) +
-				     item_offset);
-				const u64 next_bytenr =
-				    le64_to_cpu(root_item->bytenr);
+				struct btrfs_root_item root_item;
+				u32 root_item_offset;
+				u64 next_bytenr;
+
+				root_item_offset = item_offset +
+					offsetof(struct btrfs_leaf, items);
+				if (root_item_offset +
+				    sizeof(struct btrfs_root_item) >
+				    sf->block_ctx->len)
+					goto leaf_item_out_of_bounce_error;
+				btrfsic_read_from_block_data(
+					sf->block_ctx, &root_item,
+					root_item_offset,
+					sizeof(struct btrfs_root_item));
+				next_bytenr = le64_to_cpu(root_item.bytenr);
 
 				sf->error =
 				    btrfsic_create_link_to_next_block(
@@ -1041,7 +1078,7 @@ continue_with_current_leaf_stack_frame:
 						&sf->num_copies,
 						&sf->mirror_num,
 						disk_key,
-						le64_to_cpu(root_item->
+						le64_to_cpu(root_item.
 						generation));
 				if (sf->error)
 					goto one_stack_frame_backwards;
@@ -1049,7 +1086,7 @@ continue_with_current_leaf_stack_frame:
 				if (NULL != sf->next_block) {
 					struct btrfs_header *const next_hdr =
 					    (struct btrfs_header *)
-					    sf->next_block_ctx.data;
+					    sf->next_block_ctx.datav[0];
 
 					next_stack =
 					    btrfsic_stack_frame_alloc();
@@ -1111,10 +1148,24 @@ continue_with_current_node_stack_frame:
 		}
 
 		if (sf->i < sf->nr) {
-			struct btrfs_key_ptr *disk_key_ptr =
-			    nodehdr->ptrs + sf->i;
-			const u64 next_bytenr =
-			    le64_to_cpu(disk_key_ptr->blockptr);
+			struct btrfs_key_ptr key_ptr;
+			u32 key_ptr_offset;
+			u64 next_bytenr;
+
+			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
+					  (uintptr_t)nodehdr;
+			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
+			    sf->block_ctx->len) {
+				printk(KERN_INFO
+				       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
+				       sf->block_ctx->start,
+				       sf->block_ctx->dev->name);
+				goto one_stack_frame_backwards;
+			}
+			btrfsic_read_from_block_data(
+				sf->block_ctx, &key_ptr, key_ptr_offset,
+				sizeof(struct btrfs_key_ptr));
+			next_bytenr = le64_to_cpu(key_ptr.blockptr);
 
 			sf->error = btrfsic_create_link_to_next_block(
 					state,
@@ -1127,15 +1178,15 @@ continue_with_current_node_stack_frame:
 					force_iodone_flag,
 					&sf->num_copies,
 					&sf->mirror_num,
-					&disk_key_ptr->key,
-					le64_to_cpu(disk_key_ptr->generation));
+					&key_ptr.key,
+					le64_to_cpu(key_ptr.generation));
 			if (sf->error)
 				goto one_stack_frame_backwards;
 
 			if (NULL != sf->next_block) {
 				struct btrfs_header *const next_hdr =
 				    (struct btrfs_header *)
-				    sf->next_block_ctx.data;
+				    sf->next_block_ctx.datav[0];
 
 				next_stack = btrfsic_stack_frame_alloc();
 				if (NULL == next_stack)
@@ -1181,6 +1232,35 @@ one_stack_frame_backwards:
 	return sf->error;
 }
 
+static void btrfsic_read_from_block_data(
+	struct btrfsic_block_data_ctx *block_ctx,
+	void *dstv, u32 offset, size_t len)
+{
+	size_t cur;
+	size_t offset_in_page;
+	char *kaddr;
+	char *dst = (char *)dstv;
+	size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
+	unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
+
+	WARN_ON(offset + len > block_ctx->len);
+	offset_in_page = (start_offset + offset) &
+			 ((unsigned long)PAGE_CACHE_SIZE - 1);
+
+	while (len > 0) {
+		cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
+		BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
+			    PAGE_CACHE_SHIFT);
+		kaddr = block_ctx->datav[i];
+		memcpy(dst, kaddr + offset_in_page, cur);
+
+		dst += cur;
+		len -= cur;
+		offset_in_page = 0;
+		i++;
+	}
+}
+
 static int btrfsic_create_link_to_next_block(
 		struct btrfsic_state *state,
 		struct btrfsic_block *block,
@@ -1204,7 +1284,7 @@ static int btrfsic_create_link_to_next_block(
 	if (0 == *num_copiesp) {
 		*num_copiesp =
 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
-				     next_bytenr, PAGE_SIZE);
+				     next_bytenr, state->metablock_size);
 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 			       (unsigned long long)next_bytenr, *num_copiesp);
@@ -1219,7 +1299,7 @@ static int btrfsic_create_link_to_next_block(
 		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
 		       *mirror_nump);
 	ret = btrfsic_map_block(state, next_bytenr,
-				BTRFSIC_BLOCK_SIZE,
+				state->metablock_size,
 				next_block_ctx, *mirror_nump);
 	if (ret) {
 		printk(KERN_INFO
@@ -1314,7 +1394,7 @@ static int btrfsic_create_link_to_next_block(
 
 	if (limit_nesting > 0 && did_alloc_block_link) {
 		ret = btrfsic_read_block(state, next_block_ctx);
-		if (ret < (int)BTRFSIC_BLOCK_SIZE) {
+		if (ret < (int)next_block_ctx->len) {
 			printk(KERN_INFO
 			       "btrfsic: read block @logical %llu failed!\n",
 			       (unsigned long long)next_bytenr);
@@ -1339,43 +1419,74 @@ static int btrfsic_handle_extent_data(
 		u32 item_offset, int force_iodone_flag)
 {
 	int ret;
-	struct btrfs_file_extent_item *file_extent_item =
-	    (struct btrfs_file_extent_item *)(block_ctx->data +
-					      offsetof(struct btrfs_leaf,
-						       items) + item_offset);
-	u64 next_bytenr =
-	    le64_to_cpu(file_extent_item->disk_bytenr) +
-	    le64_to_cpu(file_extent_item->offset);
-	u64 num_bytes = le64_to_cpu(file_extent_item->num_bytes);
-	u64 generation = le64_to_cpu(file_extent_item->generation);
+	struct btrfs_file_extent_item file_extent_item;
+	u64 file_extent_item_offset;
+	u64 next_bytenr;
+	u64 num_bytes;
+	u64 generation;
 	struct btrfsic_block_link *l;
 
+	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
+				  item_offset;
+	if (file_extent_item_offset +
+	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
+	    block_ctx->len) {
+		printk(KERN_INFO
+		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
+		       block_ctx->start, block_ctx->dev->name);
+		return -1;
+	}
+
+	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
+		file_extent_item_offset,
+		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
+	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
+	    ((u64)0) == le64_to_cpu(file_extent_item.disk_bytenr)) {
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
+			printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
+			       file_extent_item.type,
+			       (unsigned long long)
+			       le64_to_cpu(file_extent_item.disk_bytenr));
+		return 0;
+	}
+
+	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
+	    block_ctx->len) {
+		printk(KERN_INFO
+		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
+		       block_ctx->start, block_ctx->dev->name);
+		return -1;
+	}
+	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
+				     file_extent_item_offset,
+				     sizeof(struct btrfs_file_extent_item));
+	next_bytenr = le64_to_cpu(file_extent_item.disk_bytenr) +
+		      le64_to_cpu(file_extent_item.offset);
+	generation = le64_to_cpu(file_extent_item.generation);
+	num_bytes = le64_to_cpu(file_extent_item.num_bytes);
+	generation = le64_to_cpu(file_extent_item.generation);
+
 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
 		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
 		       " offset = %llu, num_bytes = %llu\n",
-		       file_extent_item->type,
+		       file_extent_item.type,
 		       (unsigned long long)
-		       le64_to_cpu(file_extent_item->disk_bytenr),
-		       (unsigned long long)
-		       le64_to_cpu(file_extent_item->offset),
-		       (unsigned long long)
-		       le64_to_cpu(file_extent_item->num_bytes));
-	if (BTRFS_FILE_EXTENT_REG != file_extent_item->type ||
-	    ((u64)0) == le64_to_cpu(file_extent_item->disk_bytenr))
-		return 0;
+		       le64_to_cpu(file_extent_item.disk_bytenr),
+		       (unsigned long long)le64_to_cpu(file_extent_item.offset),
+		       (unsigned long long)num_bytes);
 	while (num_bytes > 0) {
 		u32 chunk_len;
 		int num_copies;
 		int mirror_num;
 
-		if (num_bytes > BTRFSIC_BLOCK_SIZE)
-			chunk_len = BTRFSIC_BLOCK_SIZE;
+		if (num_bytes > state->datablock_size)
+			chunk_len = state->datablock_size;
 		else
 			chunk_len = num_bytes;
 
 		num_copies =
 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
-				     next_bytenr, PAGE_SIZE);
+				     next_bytenr, state->datablock_size);
 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 			       (unsigned long long)next_bytenr, num_copies);
@@ -1475,8 +1586,9 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
 	block_ctx_out->start = bytenr;
 	block_ctx_out->len = len;
-	block_ctx_out->data = NULL;
-	block_ctx_out->bh = NULL;
+	block_ctx_out->datav = NULL;
+	block_ctx_out->pagev = NULL;
+	block_ctx_out->mem_to_free = NULL;
 
 	if (0 == ret)
 		kfree(multi);
@@ -1496,8 +1608,9 @@ static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
 	block_ctx_out->dev_bytenr = bytenr;
 	block_ctx_out->start = bytenr;
 	block_ctx_out->len = len;
-	block_ctx_out->data = NULL;
-	block_ctx_out->bh = NULL;
+	block_ctx_out->datav = NULL;
+	block_ctx_out->pagev = NULL;
+	block_ctx_out->mem_to_free = NULL;
 	if (NULL != block_ctx_out->dev) {
 		return 0;
 	} else {
@@ -1508,38 +1621,127 @@ static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
 
 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
 {
-	if (NULL != block_ctx->bh) {
-		brelse(block_ctx->bh);
-		block_ctx->bh = NULL;
+	if (block_ctx->mem_to_free) {
+		unsigned int num_pages;
+
+		BUG_ON(!block_ctx->datav);
+		BUG_ON(!block_ctx->pagev);
+		num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
+			    PAGE_CACHE_SHIFT;
+		while (num_pages > 0) {
+			num_pages--;
+			if (block_ctx->datav[num_pages]) {
+				kunmap(block_ctx->pagev[num_pages]);
+				block_ctx->datav[num_pages] = NULL;
+			}
+			if (block_ctx->pagev[num_pages]) {
+				__free_page(block_ctx->pagev[num_pages]);
+				block_ctx->pagev[num_pages] = NULL;
+			}
+		}
+
+		kfree(block_ctx->mem_to_free);
+		block_ctx->mem_to_free = NULL;
+		block_ctx->pagev = NULL;
+		block_ctx->datav = NULL;
 	}
 }
 
 static int btrfsic_read_block(struct btrfsic_state *state,
 			      struct btrfsic_block_data_ctx *block_ctx)
 {
-	block_ctx->bh = NULL;
-	if (block_ctx->dev_bytenr & 4095) {
+	unsigned int num_pages;
+	unsigned int i;
+	u64 dev_bytenr;
+	int ret;
+
+	BUG_ON(block_ctx->datav);
+	BUG_ON(block_ctx->pagev);
+	BUG_ON(block_ctx->mem_to_free);
+	if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
 		printk(KERN_INFO
 		       "btrfsic: read_block() with unaligned bytenr %llu\n",
 		       (unsigned long long)block_ctx->dev_bytenr);
 		return -1;
 	}
-	if (block_ctx->len > 4096) {
-		printk(KERN_INFO
-		       "btrfsic: read_block() with too huge size %d\n",
-		       block_ctx->len);
+
+	num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
+		    PAGE_CACHE_SHIFT;
+	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
+					  sizeof(*block_ctx->pagev)) *
+					 num_pages, GFP_NOFS);
+	if (!block_ctx->mem_to_free)
 		return -1;
+	block_ctx->datav = block_ctx->mem_to_free;
+	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
+	for (i = 0; i < num_pages; i++) {
+		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
+		if (!block_ctx->pagev[i])
+			return -1;
 	}
 
-	block_ctx->bh = __bread(block_ctx->dev->bdev,
-				block_ctx->dev_bytenr >> 12, 4096);
-	if (NULL == block_ctx->bh)
-		return -1;
-	block_ctx->data = block_ctx->bh->b_data;
+	dev_bytenr = block_ctx->dev_bytenr;
+	for (i = 0; i < num_pages;) {
+		struct bio *bio;
+		unsigned int j;
+		DECLARE_COMPLETION_ONSTACK(complete);
+
+		bio = bio_alloc(GFP_NOFS, num_pages - i);
+		if (!bio) {
+			printk(KERN_INFO
+			       "btrfsic: bio_alloc() for %u pages failed!\n",
+			       num_pages - i);
+			return -1;
+		}
+		bio->bi_bdev = block_ctx->dev->bdev;
+		bio->bi_sector = dev_bytenr >> 9;
+		bio->bi_end_io = btrfsic_complete_bio_end_io;
+		bio->bi_private = &complete;
+
+		for (j = i; j < num_pages; j++) {
+			ret = bio_add_page(bio, block_ctx->pagev[j],
+					   PAGE_CACHE_SIZE, 0);
+			if (PAGE_CACHE_SIZE != ret)
+				break;
+		}
+		if (j == i) {
+			printk(KERN_INFO
+			       "btrfsic: error, failed to add a single page!\n");
+			return -1;
+		}
+		submit_bio(READ, bio);
+
+		/* this will also unplug the queue */
+		wait_for_completion(&complete);
+
+		if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
+			printk(KERN_INFO
+			       "btrfsic: read error at logical %llu dev %s!\n",
+			       block_ctx->start, block_ctx->dev->name);
+			bio_put(bio);
+			return -1;
+		}
+		bio_put(bio);
+		dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
+		i = j;
+	}
+	for (i = 0; i < num_pages; i++) {
+		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
+		if (!block_ctx->datav[i]) {
+			printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
+			       block_ctx->dev->name);
+			return -1;
+		}
+	}
 
 	return block_ctx->len;
 }
 
+static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
+{
+	complete((struct completion *)bio->bi_private);
+}
+
 static void btrfsic_dump_database(struct btrfsic_state *state)
 {
 	struct list_head *elem_all;
@@ -1617,32 +1819,39 @@ static void btrfsic_dump_database(struct btrfsic_state *state)
  * (note that this test fails for the super block)
  */
 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
-				     const u8 *data, unsigned int size)
+				     char **datav, unsigned int num_pages)
 {
 	struct btrfs_header *h;
 	u8 csum[BTRFS_CSUM_SIZE];
 	u32 crc = ~(u32)0;
-	int fail = 0;
-	int crc_fail = 0;
+	unsigned int i;
 
-	h = (struct btrfs_header *)data;
+	if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
+		return 1; /* not metadata */
+	num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
+	h = (struct btrfs_header *)datav[0];
 
 	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
-		fail++;
+		return 1;
+
+	for (i = 0; i < num_pages; i++) {
+		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
+		size_t sublen = i ? PAGE_CACHE_SIZE :
+				    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
 
-	crc = crc32c(crc, data + BTRFS_CSUM_SIZE, PAGE_SIZE - BTRFS_CSUM_SIZE);
+		crc = crc32c(crc, data, sublen);
+	}
 	btrfs_csum_final(crc, csum);
 	if (memcmp(csum, h->csum, state->csum_size))
-		crc_fail++;
+		return 1;
 
-	return fail || crc_fail;
+	return 0; /* is metadata */
 }
 
 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
-					  u64 dev_bytenr,
-					  u8 *mapped_data, unsigned int len,
-					  struct bio *bio,
-					  int *bio_is_patched,
+					  u64 dev_bytenr, char **mapped_datav,
+					  unsigned int num_pages,
+					  struct bio *bio, int *bio_is_patched,
 					  struct buffer_head *bh,
 					  int submit_bio_bh_rw)
 {
@@ -1652,12 +1861,19 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 	int ret;
 	struct btrfsic_state *state = dev_state->state;
 	struct block_device *bdev = dev_state->bdev;
+	unsigned int processed_len;
 
-	WARN_ON(len > PAGE_SIZE);
-	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_data, len));
 	if (NULL != bio_is_patched)
 		*bio_is_patched = 0;
 
+again:
+	if (num_pages == 0)
+		return;
+
+	processed_len = 0;
+	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
+						      num_pages));
+
 	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
 					       &state->block_hashtable);
 	if (NULL != block) {
@@ -1667,8 +1883,16 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 
 		if (block->is_superblock) {
 			bytenr = le64_to_cpu(((struct btrfs_super_block *)
-					      mapped_data)->bytenr);
+					      mapped_datav[0])->bytenr);
+			if (num_pages * PAGE_CACHE_SIZE <
+			    BTRFS_SUPER_INFO_SIZE) {
+				printk(KERN_INFO
+				       "btrfsic: cannot work with too short bios!\n");
+				return;
+			}
 			is_metadata = 1;
+			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
+			processed_len = BTRFS_SUPER_INFO_SIZE;
 			if (state->print_mask &
 			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
 				printk(KERN_INFO
@@ -1678,12 +1902,18 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 		}
 		if (is_metadata) {
 			if (!block->is_superblock) {
+				if (num_pages * PAGE_CACHE_SIZE <
+				    state->metablock_size) {
+					printk(KERN_INFO
+					       "btrfsic: cannot work with too short bios!\n");
+					return;
+				}
+				processed_len = state->metablock_size;
 				bytenr = le64_to_cpu(((struct btrfs_header *)
-						      mapped_data)->bytenr);
+						      mapped_datav[0])->bytenr);
 				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
 							       dev_state,
-							       dev_bytenr,
-							       mapped_data);
+							       dev_bytenr);
 			}
 			if (block->logical_bytenr != bytenr) {
 				printk(KERN_INFO
@@ -1710,6 +1940,13 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 				       block->mirror_num,
 				       btrfsic_get_block_type(state, block));
 		} else {
+			if (num_pages * PAGE_CACHE_SIZE <
+			    state->datablock_size) {
+				printk(KERN_INFO
+				       "btrfsic: cannot work with too short bios!\n");
+				return;
+			}
+			processed_len = state->datablock_size;
 			bytenr = block->logical_bytenr;
 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 				printk(KERN_INFO
@@ -1747,7 +1984,7 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 			       le64_to_cpu(block->disk_key.offset),
 			       (unsigned long long)
 			       le64_to_cpu(((struct btrfs_header *)
-					    mapped_data)->generation),
+					    mapped_datav[0])->generation),
 			       (unsigned long long)
 			       state->max_superblock_generation);
 			btrfsic_dump_tree(state);
@@ -1765,10 +2002,10 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 			       (unsigned long long)block->generation,
 			       (unsigned long long)
 			       le64_to_cpu(((struct btrfs_header *)
-					    mapped_data)->generation));
+					    mapped_datav[0])->generation));
 			/* it would not be safe to go on */
 			btrfsic_dump_tree(state);
-			return;
+			goto continue_loop;
 		}
 
 		/*
@@ -1796,18 +2033,19 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 		}
 
 		if (block->is_superblock)
-			ret = btrfsic_map_superblock(state, bytenr, len,
+			ret = btrfsic_map_superblock(state, bytenr,
+						     processed_len,
 						     bdev, &block_ctx);
 		else
-			ret = btrfsic_map_block(state, bytenr, len,
+			ret = btrfsic_map_block(state, bytenr, processed_len,
 						&block_ctx, 0);
 		if (ret) {
 			printk(KERN_INFO
 			       "btrfsic: btrfsic_map_block(root @%llu)"
 			       " failed!\n", (unsigned long long)bytenr);
-			return;
+			goto continue_loop;
 		}
-		block_ctx.data = mapped_data;
+		block_ctx.datav = mapped_datav;
 		/* the following is required in case of writes to mirrors,
 		 * use the same that was used for the lookup */
 		block_ctx.dev = dev_state;
@@ -1863,11 +2101,13 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 			block->logical_bytenr = bytenr;
 			block->is_metadata = 1;
 			if (block->is_superblock) {
+				BUG_ON(PAGE_CACHE_SIZE !=
+				       BTRFS_SUPER_INFO_SIZE);
 				ret = btrfsic_process_written_superblock(
 						state,
 						block,
 						(struct btrfs_super_block *)
-						mapped_data);
+						mapped_datav[0]);
 				if (state->print_mask &
 				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
 					printk(KERN_INFO
@@ -1880,8 +2120,6 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 						state,
 						block,
 						&block_ctx,
-						(struct btrfs_header *)
-						block_ctx.data,
 						0, 0);
 			}
 			if (ret)
@@ -1912,26 +2150,30 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 		u64 bytenr;
 
 		if (!is_metadata) {
+			processed_len = state->datablock_size;
 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 				printk(KERN_INFO "Written block (%s/%llu/?)"
 				       " !found in hash table, D.\n",
 				       dev_state->name,
 				       (unsigned long long)dev_bytenr);
-			if (!state->include_extent_data)
-				return;	/* ignore that written D block */
+			if (!state->include_extent_data) {
+				/* ignore that written D block */
+				goto continue_loop;
+			}
 
 			/* this is getting ugly for the
 			 * include_extent_data case... */
 			bytenr = 0;	/* unknown */
 			block_ctx.start = bytenr;
-			block_ctx.len = len;
-			block_ctx.bh = NULL;
+			block_ctx.len = processed_len;
+			block_ctx.mem_to_free = NULL;
+			block_ctx.pagev = NULL;
 		} else {
+			processed_len = state->metablock_size;
 			bytenr = le64_to_cpu(((struct btrfs_header *)
-					      mapped_data)->bytenr);
+					      mapped_datav[0])->bytenr);
 			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
-						       dev_bytenr,
-						       mapped_data);
+						       dev_bytenr);
 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 				printk(KERN_INFO
 				       "Written block @%llu (%s/%llu/?)"
@@ -1940,17 +2182,17 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 				       dev_state->name,
 				       (unsigned long long)dev_bytenr);
 
-			ret = btrfsic_map_block(state, bytenr, len, &block_ctx,
-						0);
+			ret = btrfsic_map_block(state, bytenr, processed_len,
+						&block_ctx, 0);
 			if (ret) {
 				printk(KERN_INFO
 				       "btrfsic: btrfsic_map_block(root @%llu)"
 				       " failed!\n",
 				       (unsigned long long)dev_bytenr);
-				return;
+				goto continue_loop;
 			}
 		}
-		block_ctx.data = mapped_data;
+		block_ctx.datav = mapped_datav;
 		/* the following is required in case of writes to mirrors,
 		 * use the same that was used for the lookup */
 		block_ctx.dev = dev_state;
@@ -1960,7 +2202,7 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 		if (NULL == block) {
 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 			btrfsic_release_block_ctx(&block_ctx);
-			return;
+			goto continue_loop;
 		}
 		block->dev_state = dev_state;
 		block->dev_bytenr = dev_bytenr;
@@ -2020,9 +2262,7 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 
 		if (is_metadata) {
 			ret = btrfsic_process_metablock(state, block,
-							&block_ctx,
-							(struct btrfs_header *)
-							block_ctx.data, 0, 0);
+							&block_ctx, 0, 0);
 			if (ret)
 				printk(KERN_INFO
 				       "btrfsic: process_metablock(root @%llu)"
@@ -2031,6 +2271,13 @@ static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 		}
 		btrfsic_release_block_ctx(&block_ctx);
 	}
+
+continue_loop:
+	BUG_ON(!processed_len);
+	dev_bytenr += processed_len;
+	mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
+	num_pages -= processed_len >> PAGE_CACHE_SHIFT;
+	goto again;
 }
 
 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
@@ -2213,7 +2460,7 @@ static int btrfsic_process_written_superblock(
 
 		num_copies =
 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
-				     next_bytenr, PAGE_SIZE);
+				     next_bytenr, BTRFS_SUPER_INFO_SIZE);
 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 			       (unsigned long long)next_bytenr, num_copies);
@@ -2224,7 +2471,8 @@ static int btrfsic_process_written_superblock(
 				printk(KERN_INFO
 				       "btrfsic_process_written_superblock("
 				       "mirror_num=%d)\n", mirror_num);
-			ret = btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
+			ret = btrfsic_map_block(state, next_bytenr,
+						BTRFS_SUPER_INFO_SIZE,
 						&tmp_next_block_ctx,
 						mirror_num);
 			if (ret) {
@@ -2689,7 +2937,7 @@ static struct btrfsic_block *btrfsic_block_lookup_or_add(
 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 					   u64 bytenr,
 					   struct btrfsic_dev_state *dev_state,
-					   u64 dev_bytenr, char *data)
+					   u64 dev_bytenr)
 {
 	int num_copies;
 	int mirror_num;
@@ -2698,10 +2946,10 @@ static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 	int match = 0;
 
 	num_copies = btrfs_num_copies(&state->root->fs_info->mapping_tree,
-				      bytenr, PAGE_SIZE);
+				      bytenr, state->metablock_size);
 
 	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
-		ret = btrfsic_map_block(state, bytenr, PAGE_SIZE,
+		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
 					&block_ctx, mirror_num);
 		if (ret) {
 			printk(KERN_INFO "btrfsic:"
@@ -2727,7 +2975,8 @@ static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 		       (unsigned long long)bytenr, dev_state->name,
 		       (unsigned long long)dev_bytenr);
 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
-			ret = btrfsic_map_block(state, bytenr, PAGE_SIZE,
+			ret = btrfsic_map_block(state, bytenr,
+						state->metablock_size,
 						&block_ctx, mirror_num);
 			if (ret)
 				continue;
@@ -2781,13 +3030,13 @@ int btrfsic_submit_bh(int rw, struct buffer_head *bh)
 			       (unsigned long)bh->b_size, bh->b_data,
 			       bh->b_bdev);
 		btrfsic_process_written_block(dev_state, dev_bytenr,
-					      bh->b_data, bh->b_size, NULL,
+					      &bh->b_data, 1, NULL,
 					      NULL, bh, rw);
 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
 		if (dev_state->state->print_mask &
 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
 			printk(KERN_INFO
-			       "submit_bh(rw=0x%x) FLUSH, bdev=%p)\n",
+			       "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
 			       rw, bh->b_bdev);
 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
 			if ((dev_state->state->print_mask &
@@ -2836,6 +3085,7 @@ void btrfsic_submit_bio(int rw, struct bio *bio)
 		unsigned int i;
 		u64 dev_bytenr;
 		int bio_is_patched;
+		char **mapped_datav;
 
 		dev_bytenr = 512 * bio->bi_sector;
 		bio_is_patched = 0;
@@ -2848,35 +3098,46 @@ void btrfsic_submit_bio(int rw, struct bio *bio)
 			       (unsigned long long)dev_bytenr,
 			       bio->bi_bdev);
 
+		mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
+				       GFP_NOFS);
+		if (!mapped_datav)
+			goto leave;
 		for (i = 0; i < bio->bi_vcnt; i++) {
-			u8 *mapped_data;
-
-			mapped_data = kmap(bio->bi_io_vec[i].bv_page);
+			BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
+			mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
+			if (!mapped_datav[i]) {
+				while (i > 0) {
+					i--;
+					kunmap(bio->bi_io_vec[i].bv_page);
+				}
+				kfree(mapped_datav);
+				goto leave;
+			}
 			if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
 			     BTRFSIC_PRINT_MASK_VERBOSE) ==
 			    (dev_state->state->print_mask &
 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
 			      BTRFSIC_PRINT_MASK_VERBOSE)))
 				printk(KERN_INFO
-				       "#%u: page=%p, mapped=%p, len=%u,"
-				       " offset=%u\n",
+				       "#%u: page=%p, len=%u, offset=%u\n",
 				       i, bio->bi_io_vec[i].bv_page,
-				       mapped_data,
 				       bio->bi_io_vec[i].bv_len,
 				       bio->bi_io_vec[i].bv_offset);
-			btrfsic_process_written_block(dev_state, dev_bytenr,
-						      mapped_data,
-						      bio->bi_io_vec[i].bv_len,
-						      bio, &bio_is_patched,
-						      NULL, rw);
+		}
+		btrfsic_process_written_block(dev_state, dev_bytenr,
+					      mapped_datav, bio->bi_vcnt,
+					      bio, &bio_is_patched,
+					      NULL, rw);
+		while (i > 0) {
+			i--;
 			kunmap(bio->bi_io_vec[i].bv_page);
-			dev_bytenr += bio->bi_io_vec[i].bv_len;
 		}
+		kfree(mapped_datav);
 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
 		if (dev_state->state->print_mask &
 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
 			printk(KERN_INFO
-			       "submit_bio(rw=0x%x) FLUSH, bdev=%p)\n",
+			       "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
 			       rw, bio->bi_bdev);
 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
 			if ((dev_state->state->print_mask &
@@ -2903,6 +3164,7 @@ void btrfsic_submit_bio(int rw, struct bio *bio)
 			bio->bi_end_io = btrfsic_bio_end_io;
 		}
 	}
+leave:
 	mutex_unlock(&btrfsic_mutex);
 
 	submit_bio(rw, bio);
@@ -2917,6 +3179,30 @@ int btrfsic_mount(struct btrfs_root *root,
 	struct list_head *dev_head = &fs_devices->devices;
 	struct btrfs_device *device;
 
+	if (root->nodesize != root->leafsize) {
+		printk(KERN_INFO
+		       "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
+		       root->nodesize, root->leafsize);
+		return -1;
+	}
+	if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
+		printk(KERN_INFO
+		       "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
+		       root->nodesize, (unsigned long)PAGE_CACHE_SIZE);
+		return -1;
+	}
+	if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
+		printk(KERN_INFO
+		       "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
+		       root->leafsize, (unsigned long)PAGE_CACHE_SIZE);
+		return -1;
+	}
+	if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
+		printk(KERN_INFO
+		       "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
+		       root->sectorsize, (unsigned long)PAGE_CACHE_SIZE);
+		return -1;
+	}
 	state = kzalloc(sizeof(*state), GFP_NOFS);
 	if (NULL == state) {
 		printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
@@ -2933,6 +3219,8 @@ int btrfsic_mount(struct btrfs_root *root,
 	state->print_mask = print_mask;
 	state->include_extent_data = including_extent_data;
 	state->csum_size = 0;
+	state->metablock_size = root->nodesize;
+	state->datablock_size = root->sectorsize;
 	INIT_LIST_HEAD(&state->all_blocks_list);
 	btrfsic_block_hashtable_init(&state->block_hashtable);
 	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
@@ -3049,7 +3337,7 @@ void btrfsic_unmount(struct btrfs_root *root,
 				btrfsic_block_link_free(l);
 		}
 
-		if (b_all->is_iodone)
+		if (b_all->is_iodone || b_all->never_written)
 			btrfsic_block_free(b_all);
 		else
 			printk(KERN_INFO "btrfs: attempt to free %c-block"