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refactor(tvix/store/fs): move inode for store_path lookup to helper

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This makes it much harder to keep the read lock around for too long, and
the code a bit easier to understand.

Change-Id: I7d99c85cadd433cad444b8edd34e2c43d7eaf5a8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9977
Tested-by: BuildkiteCI
Reviewed-by: Connor Brewster <cbrewster@hey.com>
This commit is contained in:
Florian Klink 2023-11-07 10:28:49 +02:00 committed by flokli
parent a8e7f4eadb
commit f3a240bf86
1 changed files with 13 additions and 19 deletions
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32
tvix/store/src/fs/mod.rs
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@ -124,6 +124,13 @@ impl TvixStoreFs {
}
}
/// Retrieves the inode for a given StorePath, if present.
/// This obtains a read lock on self.store_paths.
fn get_inode_for_store_path(&self, store_path: &StorePath) -> Option<u64> {
let store_paths = self.store_paths.read();
store_paths.get(store_path).cloned()
}
/// This will turn a lookup request for [std::ffi::OsStr] in the root to
/// a ino and [InodeData].
/// It will peek in [self.store_paths], and then either look it up from
@ -151,14 +158,7 @@ impl TvixStoreFs {
return Ok(None);
};
let ino = {
// This extra scope makes sure we drop the read lock
// immediately after reading, to prevent deadlocks.
let store_paths = self.store_paths.read();
store_paths.get(&store_path).cloned()
};
if let Some(ino) = ino {
if let Some(ino) = self.get_inode_for_store_path(&store_path) {
// If we already have that store path, lookup the inode from
// self.store_paths and then get the data from [self.inode_tracker],
// which in the case of a [InodeData::Directory] will be fully
@ -396,22 +396,16 @@ impl FileSystem for TvixStoreFs {
let root_node = path_info.node.unwrap().node.unwrap();
let store_path = StorePath::from_bytes(root_node.get_name()).unwrap();
let ino = {
// This extra scope makes sure we drop the read lock
// immediately after reading, to prevent deadlocks.
let store_paths = self.store_paths.read();
store_paths.get(&store_path).cloned()
};
let ino = match ino {
Some(ino) => ino,
None => {
// obtain the inode, or allocate a new one.
let ino = self
.get_inode_for_store_path(&store_path)
.unwrap_or_else(|| {
// insert the (sparse) inode data and register in
// self.store_paths.
let ino = self.inode_tracker.write().put((&root_node).into());
self.store_paths.write().insert(store_path.clone(), ino);
ino
}
};
});
let ty = match root_node {
Node::Directory(_) => libc::S_IFDIR,