From 351d17fca2cf8063f323a060cd3c4af62ef58d15 Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Tue, 13 May 2008 13:48:58 -0400
Subject: Verify parent generation number on btree reads

---
 btrfs-vol.c   |  5 ++++-
 convert.c     |  2 +-
 ctree.c       |  2 +-
 disk-io.c     | 47 +++++++++++++++++++++++++++++++++++++++--------
 disk-io.h     |  2 +-
 extent-tree.c |  4 ++--
 extent_io.c   |  8 ++++++++
 extent_io.h   |  2 ++
 8 files changed, 58 insertions(+), 14 deletions(-)

diff --git a/btrfs-vol.c b/btrfs-vol.c
index 9eddd782..80697783 100644
--- a/btrfs-vol.c
+++ b/btrfs-vol.c
@@ -105,7 +105,10 @@ int main(int ac, char **av)
 		print_usage();
 	mnt = av[optind];
 
-	if (device) {
+	if (device && strcmp(device, "missing") == 0 &&
+	    cmd == BTRFS_IOC_RM_DEV) {
+		fprintf(stderr, "removing missing devices from %s\n", mnt);
+	} else if (device) {
 		devfd = open(device, O_RDWR);
 		if (!devfd) {
 			fprintf(stderr, "Unable to open device %s\n", device);
diff --git a/convert.c b/convert.c
index 219f849b..3c00544c 100644
--- a/convert.c
+++ b/convert.c
@@ -1094,7 +1094,7 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
 	u32 blocksize = ext2_fs->blocksize;
 	u32 block = start_byte / blocksize;
 	u32 last_block = (end_byte + blocksize - 1) / blocksize;
-	int ret;
+	int ret = 0;
 	struct blk_iterate_data data = {
 		.trans		= trans,
 		.root		= root,
diff --git a/ctree.c b/ctree.c
index 87574d9e..881c115b 100644
--- a/ctree.c
+++ b/ctree.c
@@ -378,7 +378,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 
 		cur = btrfs_find_tree_block(root, blocknr, blocksize);
 		if (cur)
-			uptodate = btrfs_buffer_uptodate(cur);
+			uptodate = btrfs_buffer_uptodate(cur, gen);
 		else
 			uptodate = 0;
 		if (!cur || !uptodate) {
diff --git a/disk-io.c b/disk-io.c
index 687cc61e..f2cbd4af 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -106,7 +106,7 @@ int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 	struct btrfs_device *device;
 
 	eb = btrfs_find_tree_block(root, bytenr, blocksize);
-	if (eb && btrfs_buffer_uptodate(eb)) {
+	if (eb && btrfs_buffer_uptodate(eb, parent_transid)) {
 		free_extent_buffer(eb);
 		return 0;
 	}
@@ -124,6 +124,31 @@ int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 	return 0;
 }
 
+static int verify_parent_transid(struct extent_io_tree *io_tree,
+				 struct extent_buffer *eb, u64 parent_transid)
+{
+	int ret;
+
+	if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
+		return 0;
+
+	if (extent_buffer_uptodate(eb) &&
+	    btrfs_header_generation(eb) == parent_transid) {
+		ret = 0;
+		goto out;
+	}
+	printk("parent transid verify failed on %llu wanted %llu found %llu\n",
+	       (unsigned long long)eb->start,
+	       (unsigned long long)parent_transid,
+	       (unsigned long long)btrfs_header_generation(eb));
+	ret = 1;
+out:
+	clear_extent_buffer_uptodate(io_tree, eb);
+	return ret;
+
+}
+
+
 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 				     u32 blocksize, u64 parent_transid)
 {
@@ -140,7 +165,7 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 	if (!eb)
 		return NULL;
 
-	if (btrfs_buffer_uptodate(eb))
+	if (btrfs_buffer_uptodate(eb, parent_transid))
 		return eb;
 
 	dev_nr = 0;
@@ -156,19 +181,18 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 		kfree(multi);
 		ret = read_extent_from_disk(eb);
 		if (ret == 0 && check_tree_block(root, eb) == 0 &&
-		    csum_tree_block(root, eb, 1) == 0) {
+		    csum_tree_block(root, eb, 1) == 0 &&
+		    verify_parent_transid(eb->tree, eb, parent_transid) == 0) {
 			btrfs_set_buffer_uptodate(eb);
 			return eb;
 		}
 		num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 					      eb->start, eb->len);
 		if (num_copies == 1) {
-printk("reading %Lu failed only one copy\n", eb->start);
 			break;
 		}
 		mirror_num++;
 		if (mirror_num > num_copies) {
-printk("bailing at mirror %d of %d\n", mirror_num, num_copies);
 			break;
 		}
 	}
@@ -186,7 +210,7 @@ int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 
 	if (check_tree_block(root, eb))
 		BUG();
-	if (!btrfs_buffer_uptodate(eb))
+	if (!btrfs_buffer_uptodate(eb, trans->transid))
 		BUG();
 
 	btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
@@ -773,9 +797,16 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *eb)
 	set_extent_buffer_dirty(eb);
 }
 
-int btrfs_buffer_uptodate(struct extent_buffer *eb)
+int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
 {
-	return extent_buffer_uptodate(eb);
+	int ret;
+
+	ret = extent_buffer_uptodate(buf);
+	if (!ret)
+		return ret;
+
+	ret = verify_parent_transid(buf->tree, buf, parent_transid);
+	return !ret;
 }
 
 int btrfs_set_buffer_uptodate(struct extent_buffer *eb)
diff --git a/disk-io.h b/disk-io.h
index ffb4114b..098f9e33 100644
--- a/disk-io.h
+++ b/disk-io.h
@@ -46,7 +46,7 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 				      struct btrfs_key *location);
 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root);
 void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
-int btrfs_buffer_uptodate(struct extent_buffer *buf);
+int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid);
 int btrfs_set_buffer_uptodate(struct extent_buffer *buf);
 int wait_on_tree_block_writeback(struct btrfs_root *root,
 				 struct extent_buffer *buf);
diff --git a/extent-tree.c b/extent-tree.c
index 545884a9..767867f9 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -1253,7 +1253,7 @@ static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
 	if (!pending) {
 		buf = btrfs_find_tree_block(root, bytenr, num_bytes);
 		if (buf) {
-			if (btrfs_buffer_uptodate(buf)) {
+			if (btrfs_buffer_uptodate(buf, 0)) {
 				u64 transid =
 				    root->fs_info->running_transaction->transid;
 				if (btrfs_header_generation(buf) ==
@@ -1967,7 +1967,7 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
 			continue;
 		}
 		next = btrfs_find_tree_block(root, bytenr, blocksize);
-		if (!next || !btrfs_buffer_uptodate(next)) {
+		if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
 			free_extent_buffer(next);
 			reada_walk_down(root, cur, path->slots[*level]);
 			mutex_unlock(&root->fs_info->fs_mutex);
diff --git a/extent_io.c b/extent_io.c
index ef888d91..4920b291 100644
--- a/extent_io.c
+++ b/extent_io.c
@@ -1,3 +1,4 @@
+
 /*
  * Copyright (C) 2007 Oracle.  All rights reserved.
  *
@@ -688,6 +689,13 @@ int set_extent_buffer_uptodate(struct extent_buffer *eb)
 	return 0;
 }
 
+int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
+				struct extent_buffer *eb)
+{
+	eb->flags &= ~EXTENT_UPTODATE;
+	return 0;
+}
+
 int extent_buffer_uptodate(struct extent_buffer *eb)
 {
 	if (eb->flags & EXTENT_UPTODATE)
diff --git a/extent_io.h b/extent_io.h
index 2bd4179e..a5d6bf0e 100644
--- a/extent_io.h
+++ b/extent_io.h
@@ -84,6 +84,8 @@ int clear_extent_dirty(struct extent_io_tree *tree, u64 start,
 		       u64 end, gfp_t mask);
 int extent_buffer_uptodate(struct extent_buffer *eb);
 int set_extent_buffer_uptodate(struct extent_buffer *eb);
+int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
+				struct extent_buffer *eb);
 int set_state_private(struct extent_io_tree *tree, u64 start, u64 private);
 int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private);
 struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
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