make it work with zfs 0.8

The parent of this commit was based on ZoL 0.8-rcX some time in Feb-April 2019.

Since then, some changes happend to the zfs send code that broke the parent commit.

Changes made in this commit:

- Handle FREEOBJECTS(firstobj=X, numobjs=u64max-X)
  Apparently, this wasn't a thing in April 19, cannot remember exactly.

- fixup from_ivset_guid field when squashing
  => f00ab3f22cc2c7f62cfd56be842945667b1d558f (from_ivset_guid was added to stream format)

- 'show' subcommand to dump LSM's internal state

- cargo fmt

bindings/build.rs

@@ -8,7 +8,12 @@ fn main() {
     let helpers = Path::new(&dir).join("./helpers");
 
     // compile helpers lib
-    cc::Build::new().file(helpers.join("helpers.c")).flag("-Werror").flag("-Wall").flag("-Wpedantic").compile("helpers");
+    cc::Build::new()
+        .file(helpers.join("helpers.c"))
+        .flag("-Werror")
+        .flag("-Wall")
+        .flag("-Wpedantic")
+        .compile("helpers");
 
     let clang_args = [format!("-I{}", helpers.display())];
     let bindings = bindgen::Builder::default()

bindings/src/lib.rs

@@ -1,5 +1,3 @@
-
-
 mod generated;
 pub use generated::*;
 

zquash/src/dmu_stream.rs

@@ -47,7 +47,6 @@ impl ReplayRecordExt for dmu_replay_record {
     }
 }
 
-
 #[derive(Clone)]
 pub struct RecordWithPayload {
     pub drr: dmu_replay_record,
@@ -64,6 +63,79 @@ impl fmt::Debug for RecordWithPayload {
     }
 }
 
+#[derive(Debug)]
+pub enum DrrBeginMutateNvlistError<E: std::fmt::Debug> {
+    DecodeOuterNvlist,
+    LookupCryptKeydata,
+    MutationCallbackError(E),
+    PackingFailedMutationNotCommitted,
+}
+
+impl RecordWithPayload {
+    pub unsafe fn drr_begin_mutate_crypt_keydata<O, E: std::fmt::Debug, F>(
+        &mut self,
+        cb: F,
+    ) -> Result<O, DrrBeginMutateNvlistError<E>>
+    where
+        F: FnOnce(*mut nvpair_sys::nvlist_t) -> Result<O, E>,
+    {
+        assert_eq!(self.drr.drr_type, dmu_replay_record_DRR_BEGIN);
+
+        use const_cstr::const_cstr;
+        let buf = self.payload.as_mut_ptr();
+        let mut deser: *mut nvpair_sys::nvlist_t = std::ptr::null_mut();
+        if nvpair_sys::nvlist_unpack(buf as *mut i8, self.payload.len(), &mut deser, 0) != 0 {
+            return Err(DrrBeginMutateNvlistError::DecodeOuterNvlist);
+        }
+
+        let mut crypt_keydata: *mut nvpair_sys::nvlist_t = std::ptr::null_mut();
+        if nvpair_sys::nvlist_lookup_nvlist(
+            deser,
+            const_cstr!("crypt_keydata").as_ptr(),
+            &mut crypt_keydata,
+        ) != 0
+        {
+            nvpair_sys::nvlist_free(deser);
+            return Err(DrrBeginMutateNvlistError::LookupCryptKeydata);
+        }
+
+        let cbres = cb(crypt_keydata);
+
+        if cbres.is_ok() {
+            // commit mutations by replacing self.payload with updated one
+            let mut packed_allocated_buf: *mut i8 = std::ptr::null_mut();
+            let mut packed_allocated_buf_size: usize = 0;
+            if nvpair_sys::nvlist_pack(
+                deser,
+                &mut packed_allocated_buf,
+                &mut packed_allocated_buf_size,
+                nvpair_sys::NV_ENCODE_NATIVE,
+                0,
+            ) != 0
+            {
+                nvpair_sys::nvlist_free(deser);
+                return Err(DrrBeginMutateNvlistError::PackingFailedMutationNotCommitted);
+            }
+            let buf_as_slice = std::slice::from_raw_parts(
+                packed_allocated_buf as *const u8,
+                packed_allocated_buf_size,
+            );
+            assert_eq!(self.payload.len(), self.drr.drr_payloadlen as usize);
+            self.payload = Vec::from(buf_as_slice); // copy
+            use std::convert::TryInto;
+            self.drr.drr_payloadlen = packed_allocated_buf_size.try_into().unwrap();
+            libc::free(packed_allocated_buf as *mut std::ffi::c_void);
+        }
+
+        nvpair_sys::nvlist_free(deser);
+
+        match cbres {
+            Ok(o) => Ok(o),
+            Err(e) => Err(DrrBeginMutateNvlistError::MutationCallbackError(e)),
+        }
+    }
+}
+
 pub struct Record<'r> {
     pub header: dmu_replay_record,
     pub payload_len: u64,

zquash/src/fletcher4.rs

@@ -63,5 +63,4 @@ impl Fletcher4 {
     pub fn checksum(&self) -> [u64; 4] {
         [self.a, self.b, self.c, self.d]
     }
-
 }

zquash/src/lib.rs

@@ -4,4 +4,4 @@ extern crate derive_more;
 pub mod dmu_stream;
 pub mod fletcher4;
 pub mod lsm;
-pub mod split_tree;
+pub mod split_tree;

zquash/src/lsm/lsm.rs

@@ -1,5 +1,3 @@
-
-
 extern crate bincode;
 extern crate serde;
 
@@ -231,9 +229,7 @@ pub struct SortedLSMWriter<K: Ord, V> {
 }
 
 impl<K: Ord + Serialize + DeserializeOwned, V: Serialize + DeserializeOwned> SortedLSMWriter<K, V> {
-    pub fn new(
-        path: &std::path::Path
-    ) -> SortedLSMWriter<K, V> {
+    pub fn new(path: &std::path::Path) -> SortedLSMWriter<K, V> {
         SortedLSMWriter {
             file: std::io::BufWriter::new(std::fs::File::create(path).unwrap()),
             last_entry: None,
@@ -280,5 +276,3 @@ mod tests {
         std::fs::remove_file(&pathout);
     }
 }
-
-