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move fn crashsafe_overwrite to minimize diff

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This commit is contained in:
Christian Schwarz
2023-12-12 15:01:09 +00:00
parent 70c6838c9a
commit 65b56ae32f
1 changed files with 45 additions and 45 deletions
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90
pageserver/src/virtual_file.rs
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@@ -327,51 +327,6 @@ impl VirtualFile {
Self::open_with_options(path, options).await
}
/// Writes a file to the specified `final_path` in a crash safe fasion
///
/// The file is first written to the specified tmp_path, and in a second
/// step, the tmp path is renamed to the final path. As renames are
/// atomic, a crash during the write operation will never leave behind a
/// partially written file.
pub async fn crashsafe_overwrite(
final_path: &Utf8Path,
tmp_path: &Utf8Path,
content: &[u8],
) -> std::io::Result<()> {
let Some(final_path_parent) = final_path.parent() else {
return Err(std::io::Error::from_raw_os_error(
nix::errno::Errno::EINVAL as i32,
));
};
std::fs::remove_file(tmp_path).or_else(fs_ext::ignore_not_found)?;
let mut file = {
let mut options = tokio_epoll_uring::ops::open_at::OpenOptions::new();
options
.write(true)
// Use `create_new` so that, if we race with ourselves or something else,
// we bail out instead of causing damage.
.create_new(true);
Self::open_with_options(tmp_path, options).await?
};
file.write_all(content).await?;
file.sync_all().await?;
drop(file); // before the rename, that's important!
// renames are atomic
std::fs::rename(tmp_path, final_path)?;
// Only open final path parent dirfd now, so that this operation only
// ever holds one VirtualFile fd at a time. That's important because
// the current `find_victim_slot` impl might pick the same slot for both
// VirtualFile., and it eventually does a blocking write lock instead of
// try_lock.
let final_parent_dirfd = {
let mut options = tokio_epoll_uring::ops::open_at::OpenOptions::new();
options.read(true);
Self::open_with_options(final_path_parent, options).await?
};
final_parent_dirfd.sync_all().await?;
Ok(())
}
/// Open a file with given options.
///
/// Note: If any custom flags were set in 'open_options' through OpenOptionsExt,
@@ -430,6 +385,51 @@ impl VirtualFile {
Ok(vfile)
}
/// Writes a file to the specified `final_path` in a crash safe fasion
///
/// The file is first written to the specified tmp_path, and in a second
/// step, the tmp path is renamed to the final path. As renames are
/// atomic, a crash during the write operation will never leave behind a
/// partially written file.
pub async fn crashsafe_overwrite(
final_path: &Utf8Path,
tmp_path: &Utf8Path,
content: &[u8],
) -> std::io::Result<()> {
let Some(final_path_parent) = final_path.parent() else {
return Err(std::io::Error::from_raw_os_error(
nix::errno::Errno::EINVAL as i32,
));
};
std::fs::remove_file(tmp_path).or_else(fs_ext::ignore_not_found)?;
let mut file = {
let mut options = tokio_epoll_uring::ops::open_at::OpenOptions::new();
options
.write(true)
// Use `create_new` so that, if we race with ourselves or something else,
// we bail out instead of causing damage.
.create_new(true);
Self::open_with_options(tmp_path, options).await?
};
file.write_all(content).await?;
file.sync_all().await?;
drop(file); // before the rename, that's important!
// renames are atomic
std::fs::rename(tmp_path, final_path)?;
// Only open final path parent dirfd now, so that this operation only
// ever holds one VirtualFile fd at a time. That's important because
// the current `find_victim_slot` impl might pick the same slot for both
// VirtualFile., and it eventually does a blocking write lock instead of
// try_lock.
let final_parent_dirfd = {
let mut options = tokio_epoll_uring::ops::open_at::OpenOptions::new();
options.read(true);
Self::open_with_options(final_path_parent, options).await?
};
final_parent_dirfd.sync_all().await?;
Ok(())
}
/// Call File::sync_all() on the underlying File.
pub async fn sync_all(&self) -> Result<(), Error> {
with_file!(self, StorageIoOperation::Fsync, |file_guard| file_guard