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builder: fix rafv5 dir size for reproducible build
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Since different filesystems may calculate different directory sizes,
for RAFS v5, nydus needs to implement the directory size calculation
itself to achieve reproducible builds on different hosts or filesystems.

For RAFS v6, the directory size is calculated by actual entries.

Signed-off-by: Yan Song <[email protected]>
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@imeoer
imeoer committed Aug 5, 2022
1 parent 2ffacea commit f6a2ecc
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Showing 2 changed files with 128 additions and 61 deletions.
28 changes: 28 additions & 0 deletions src/bin/nydus-image/builder/directory.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,12 @@ use crate::core::context::{
};
use crate::core::node::{Node, Overlay};
use crate::core::tree::Tree;
use nydus_utils::try_round_up_4k;

// The RAFS v5 format does not have directory entries, so for ensuring
// that the directory size is independent of the host filesystem for
// reproducible builds, we define a virtual dummy value here.
const RAFS_V5_VIRTUAL_ENTRY_SIZE: u8 = 8;

const TAR_BLOB_NAME: &str = "image.blob";
const TAR_BOOTSTRAP_NAME: &str = "image.boot";
Expand Down Expand Up @@ -71,6 +77,7 @@ impl FilesystemTreeBuilder {

let mut child = Tree::new(child);
child.children = self.load_children(ctx, bootstrap_ctx, &mut child.node, layer_idx)?;
DirectoryBuilder::set_v5_dir_size(&ctx.fs_version, &mut child);
result.push(child);
}

Expand All @@ -85,6 +92,26 @@ impl DirectoryBuilder {
Self {}
}

// Since different filesystems may calculate different directory sizes,
// for RAFS v5, nydus needs to implement the directory size calculation
// itself to achieve reproducible builds on different hosts or filesystems.
// For RAFS v6, the directory size is calculated by actual entries later.
fn set_v5_dir_size(fs_version: &RafsVersion, tree: &mut Tree) {
if !tree.node.is_dir() || !fs_version.is_v5() {
return;
}
let mut d_size = 0u64;
for child in tree.children.iter() {
d_size += child.node.inode.name_size() as u64 + RAFS_V5_VIRTUAL_ENTRY_SIZE as u64;
}
if d_size == 0 {
tree.node.inode.set_size(4096);
} else {
tree.node.inode.set_size(try_round_up_4k(d_size).unwrap());
}
tree.node.set_v5_inode_blocks();
}

/// Build node tree from a filesystem directory
fn build_tree_from_fs(
&mut self,
Expand All @@ -108,6 +135,7 @@ impl DirectoryBuilder {
{ tree_builder.load_children(ctx, bootstrap_ctx, &mut tree.node, layer_idx) },
"load_from_directory"
)?;
Self::set_v5_dir_size(&ctx.fs_version, &mut tree);

Ok(tree)
}
Expand Down
161 changes: 100 additions & 61 deletions src/bin/nydus-image/core/node.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -244,7 +244,7 @@ impl Display for Node {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(
f,
"{} {:?}: index {} ino {} real_ino {} i_parent {} child_index {} child_count {} i_nlink {} i_size {} i_name_size {} i_symlink_size {} has_xattr {} link {:?}",
"{} {:?}: index {} ino {} real_ino {} i_parent {} child_index {} child_count {} i_nlink {} i_size {} i_blocks {} i_name_size {} i_symlink_size {} has_xattr {} link {:?} i_mtime {} i_mtime_nsec {}",
self.file_type(),
self.target(),
self.index,
Expand All @@ -255,10 +255,13 @@ impl Display for Node {
self.inode.child_count(),
self.inode.nlink(),
self.inode.size(),
self.inode.blocks(),
self.inode.name_size(),
self.inode.symlink_size(),
self.inode.has_xattr(),
self.symlink,
self.inode.mtime(),
self.inode.mtime_nsec(),
)
}
}
Expand Down Expand Up @@ -833,6 +836,23 @@ impl Node {
Ok(())
}

// Xattr paris are located into bootstrap rather than blob, however, we should
// also reflect the size they consume like other file system. We don't
// directly use local file's metadata for `i_block` since we are purchasing
// "reproducible build" which means nydus image can be built from anywhere with
// the unique image built.
// TODO: The real size occupied within blob is compressed. Therefore, the
// sum of all chunks' size should be more accurate. But we don't know the size
// right now since compression is not acted yet. Try to make this accurate later.
pub fn set_v5_inode_blocks(&mut self) {
if let InodeWrapper::V5(_) = self.inode {
self.inode.set_blocks(div_round_up(
self.inode.size() + self.xattrs.aligned_size_v5() as u64,
512,
));
}
}

fn build_inode_stat(&mut self) -> Result<()> {
let meta = self.meta()?;

Expand All @@ -847,8 +867,28 @@ impl Node {
// (blob + bootstrap in one tar layer), which causes the layer hash to change and wastes
// registry storage space, so the mtime of the root directory is forced to be ignored here.
let ignore_mtime = self.is_root();
self.inode
.set_inode_info(&meta, &self.xattrs, self.explicit_uidgid, ignore_mtime);

self.inode.set_mode(meta.st_mode());
if self.explicit_uidgid {
self.inode.set_uid(meta.st_uid());
self.inode.set_gid(meta.st_gid());
}
if !ignore_mtime {
self.inode.set_mtime(meta.st_mtime() as u64);
self.inode.set_mtime_nsec(meta.st_mtime_nsec() as u32);
}
self.inode.set_projid(0);
self.inode.set_rdev(meta.st_rdev() as u32);
// Ignore actual nlink value and calculate from rootfs directory instead
self.inode.set_nlink(1);

// Since different filesystems may get different directory sizes/blocks,
// calculate these two values later.
if !self.is_dir() {
self.inode.set_size(meta.st_size());
// Set inode blocks for RAFS v5 dir, v6 dir's will be calculated by runtime.
self.set_v5_inode_blocks();
}

Ok(())
}
Expand Down Expand Up @@ -1291,6 +1331,13 @@ impl InodeWrapper {
}
}

pub fn set_mode(&mut self, mode: u32) {
match self {
InodeWrapper::V5(i) => i.i_mode = mode,
InodeWrapper::V6(i) => i.i_mode = mode,
}
}

pub fn is_dir(&self) -> bool {
match self {
InodeWrapper::V5(i) => i.is_dir(),
Expand Down Expand Up @@ -1426,34 +1473,83 @@ impl InodeWrapper {
}
}

pub fn set_uid(&mut self, uid: u32) {
match self {
InodeWrapper::V5(i) => i.i_uid = uid,
InodeWrapper::V6(i) => i.i_uid = uid,
}
}

pub fn gid(&self) -> u32 {
match self {
InodeWrapper::V5(i) => i.i_gid,
InodeWrapper::V6(i) => i.i_gid,
}
}

pub fn set_gid(&mut self, gid: u32) {
match self {
InodeWrapper::V5(i) => i.i_gid = gid,
InodeWrapper::V6(i) => i.i_gid = gid,
}
}

pub fn mtime(&self) -> u64 {
match self {
InodeWrapper::V5(i) => i.i_mtime,
InodeWrapper::V6(i) => i.i_mtime,
}
}

pub fn set_mtime(&mut self, mtime: u64) {
match self {
InodeWrapper::V5(i) => i.i_mtime = mtime,
InodeWrapper::V6(i) => i.i_mtime = mtime,
}
}

pub fn mtime_nsec(&self) -> u32 {
match self {
InodeWrapper::V5(i) => i.i_mtime_nsec,
InodeWrapper::V6(i) => i.i_mtime_nsec,
}
}

pub fn set_mtime_nsec(&mut self, mtime_nsec: u32) {
match self {
InodeWrapper::V5(i) => i.i_mtime_nsec = mtime_nsec,
InodeWrapper::V6(i) => i.i_mtime_nsec = mtime_nsec,
}
}

pub fn blocks(&self) -> u64 {
match self {
InodeWrapper::V5(i) => i.i_blocks,
InodeWrapper::V6(i) => i.i_blocks,
}
}

pub fn set_blocks(&mut self, blocks: u64) {
match self {
InodeWrapper::V5(i) => i.i_blocks = blocks,
InodeWrapper::V6(i) => i.i_blocks = blocks,
}
}

pub fn set_rdev(&mut self, rdev: u32) {
match self {
InodeWrapper::V5(i) => i.i_rdev = rdev,
InodeWrapper::V6(i) => i.i_rdev = rdev,
}
}

pub fn set_projid(&mut self, projid: u32) {
match self {
InodeWrapper::V5(i) => i.i_projid = projid,
InodeWrapper::V6(i) => i.i_projid = projid,
}
}

pub fn nlink(&self) -> u32 {
match self {
InodeWrapper::V5(i) => i.i_nlink,
Expand Down Expand Up @@ -1489,7 +1585,7 @@ impl InodeWrapper {
}
}

fn set_name_size(&mut self, size: usize) {
pub fn set_name_size(&mut self, size: usize) {
debug_assert!(size < u16::MAX as usize);
match self {
InodeWrapper::V5(i) => i.i_name_size = size as u16,
Expand Down Expand Up @@ -1546,63 +1642,6 @@ impl InodeWrapper {
}
}

fn set_inode_info<T: MetadataExt>(
&mut self,
meta: &T,
xattrs: &RafsXAttrs,
explicit_uidgid: bool,
ignore_mtime: bool,
) {
match self {
InodeWrapper::V5(i) => {
i.i_mode = meta.st_mode();
if explicit_uidgid {
i.i_uid = meta.st_uid();
i.i_gid = meta.st_gid();
}
if !ignore_mtime {
i.i_mtime = meta.st_mtime() as u64;
i.i_mtime_nsec = meta.st_mtime_nsec() as u32;
}
i.i_projid = 0;
i.i_size = meta.st_size();
i.i_rdev = meta.st_rdev() as u32;
// Ignore actual nlink value and calculate from rootfs directory instead
i.i_nlink = 1;

// Xattr paris are located into bootstrap rather than blob, however, we should
// also reflect the size they consume like other file system. We don't
// directly use local file's metadata for `i_block` since we are purchasing
// "reproducible build" which means nydus image can be built from anywhere with
// the unique image built.
i.i_blocks = div_round_up(i.i_size + xattrs.aligned_size_v5() as u64, 512);
}
InodeWrapper::V6(i) => {
i.i_mode = meta.st_mode();
if explicit_uidgid {
i.i_uid = meta.st_uid();
i.i_gid = meta.st_gid();
}
if !ignore_mtime {
i.i_mtime = meta.st_mtime() as u64;
i.i_mtime_nsec = meta.st_mtime_nsec() as u32;
}
i.i_projid = 0;
i.i_size = meta.st_size();
i.i_rdev = meta.st_rdev() as u32;
// Ignore actual nlink value and calculate from rootfs directory instead
i.i_nlink = 1;

// Xattr paris are located into bootstrap rather than blob, however, we should
// also reflect the size they consume like other file system. We don't
// directly use local file's metadata for `i_block` since we are purchasing
// "reproducible build" which means nydus image can be built from anywhere with
// the unique image built.
i.i_blocks = div_round_up(i.i_size + xattrs.aligned_size_v5() as u64, 512);
}
}
}

fn create_chunk(&self) -> ChunkWrapper {
match self {
InodeWrapper::V5(_) => ChunkWrapper::V5(RafsV5ChunkInfo::new()),
Expand Down

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