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authorLuke Shumaker <lukeshu@lukeshu.com>2022-08-30 19:33:01 -0600
committerLuke Shumaker <lukeshu@lukeshu.com>2022-08-30 21:29:53 -0600
commita2c5901f30d3e0a86aed320e0ed0a360ac5e4dc4 (patch)
treec5bc3b866867c5826091dfdb6139959b92711b5f /lib/btrfs
parent78f4848d38b9d5127c4f3a8d49a9c4f16b3049be (diff)
btrfstree: Don't let (most) validation errors prevent parsing
Diffstat (limited to 'lib/btrfs')
-rw-r--r--lib/btrfs/btrfstree/types_node.go25
1 files changed, 18 insertions, 7 deletions
diff --git a/lib/btrfs/btrfstree/types_node.go b/lib/btrfs/btrfstree/types_node.go
index 48a065d..58dc8e5 100644
--- a/lib/btrfs/btrfstree/types_node.go
+++ b/lib/btrfs/btrfstree/types_node.go
@@ -408,7 +408,7 @@ func ReadNode[Addr ~int64](fs diskio.File[Addr], sb Superblock, addr Addr, exp N
return nodeRef, fmt.Errorf("btrfs.ReadNode: node@%v: %w", addr, err)
}
- // sanity checking
+ // sanity checking (that prevents the main parse)
if nodeRef.Data.Head.MetadataUUID != sb.EffectiveMetadataUUID() {
return nodeRef, fmt.Errorf("btrfs.ReadNode: node@%v: %w", addr, ErrNotANode)
@@ -424,6 +424,23 @@ func ReadNode[Addr ~int64](fs diskio.File[Addr], sb Superblock, addr Addr, exp N
addr, stored, calced)
}
+ // parse (main)
+ //
+ // If the above sanity checks passed, then this is at least
+ // node data *that got written by the filesystem*. If it's
+ // invalid (the remaining sanity checks don't pass), it's
+ // because of something the running filesystem code did; the
+ // bits are probably useful to poke at, so parse them.
+ // Whereas if the above check didn't pass, then this is just
+ // garbage data that is was never a valid node, so parsing it
+ // isn't useful.
+
+ if _, err := binstruct.Unmarshal(nodeBuf, &nodeRef.Data); err != nil {
+ return nodeRef, fmt.Errorf("btrfs.ReadNode: node@%v: %w", addr, err)
+ }
+
+ // sanity checking (that doesn't prevent parsing)
+
if exp.LAddr.OK && nodeRef.Data.Head.Addr != exp.LAddr.Val {
return nodeRef, fmt.Errorf("btrfs.ReadNode: node@%v: read from laddr=%v but claims to be at laddr=%v",
addr, exp.LAddr.Val, nodeRef.Data.Head.Addr)
@@ -442,12 +459,6 @@ func ReadNode[Addr ~int64](fs diskio.File[Addr], sb Superblock, addr Addr, exp N
}
}
- // parse (main)
-
- if _, err := binstruct.Unmarshal(nodeBuf, &nodeRef.Data); err != nil {
- return nodeRef, fmt.Errorf("btrfs.ReadNode: node@%v: %w", addr, err)
- }
-
// return
return nodeRef, nil