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more safety around adding/deleting dirs

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This commit is contained in:
Scott Lamb 2018-03-01 12:24:32 -08:00
parent f01f523c2c
commit 0f2e71ec4a
3 changed files with 65 additions and 25 deletions
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69
db/db.rs
View File

@ -280,6 +280,19 @@ impl SampleFileDir {
.ok_or_else(|| format_err!("sample file dir {} is closed", self.id))?
.clone())
}
/// Returns expected existing metadata when opening this directory.
fn meta(&self, db_uuid: &Uuid) -> schema::DirMeta {
let mut meta = schema::DirMeta::default();
meta.db_uuid.extend_from_slice(&db_uuid.as_bytes()[..]);
meta.dir_uuid.extend_from_slice(&self.uuid.as_bytes()[..]);
if let Some(o) = self.last_complete_open {
let open = meta.mut_last_complete_open();
open.id = o.id;
open.uuid.extend_from_slice(&o.uuid.as_bytes()[..]);
}
meta
}
}
/// In-memory state about a camera.
@ -920,7 +933,6 @@ impl LockedDatabase {
/// in practice.
pub fn open_sample_file_dirs(&mut self, ids: &[i32]) -> Result<(), Error> {
let mut in_progress = FnvHashMap::with_capacity_and_hasher(ids.len(), Default::default());
let o = self.open.as_ref();
for &id in ids {
let e = in_progress.entry(id);
use ::std::collections::hash_map::Entry;
@ -928,33 +940,25 @@ impl LockedDatabase {
Entry::Occupied(_) => continue, // suppress duplicate.
Entry::Vacant(e) => e,
};
let dir = self
.sample_file_dirs_by_id
let dir = self.sample_file_dirs_by_id
.get_mut(&id)
.ok_or_else(|| format_err!("no such dir {}", id))?;
if dir.dir.is_some() { continue }
let mut meta = schema::DirMeta::default();
meta.db_uuid.extend_from_slice(&self.uuid.as_bytes()[..]);
meta.dir_uuid.extend_from_slice(&dir.uuid.as_bytes()[..]);
if let Some(o) = dir.last_complete_open {
let open = meta.mut_last_complete_open();
open.id = o.id;
open.uuid.extend_from_slice(&o.uuid.as_bytes()[..]);
}
if let Some(o) = o {
let mut meta = dir.meta(&self.uuid);
if let Some(o) = self.open.as_ref() {
let open = meta.mut_in_progress_open();
open.id = o.id;
open.uuid.extend_from_slice(&o.uuid.as_bytes()[..]);
}
let d = dir::SampleFileDir::open(&dir.path, &meta)?;
if o.is_none() { // read-only mode; it's already fully opened.
if self.open.is_none() { // read-only mode; it's already fully opened.
dir.dir = Some(d);
} else { // read-write mode; there are more steps to do.
e.insert((meta, d));
}
}
let o = match o {
let o = match self.open.as_ref() {
None => return Ok(()), // read-only mode; all done.
Some(o) => o,
};
@ -1391,8 +1395,7 @@ impl LockedDatabase {
let mut meta = schema::DirMeta::default();
let uuid = Uuid::new_v4();
let uuid_bytes = &uuid.as_bytes()[..];
let o = self
.open
let o = self.open
.as_ref()
.ok_or_else(|| format_err!("database is read-only"))?;
@ -1406,8 +1409,6 @@ impl LockedDatabase {
}
let dir = dir::SampleFileDir::create(&path, &meta)?;
// TODO: ensure the dir is empty?
let uuid = Uuid::new_v4();
self.conn.execute(r#"
insert into sample_file_dir (path, uuid, last_complete_open_id)
values (?, ?, ?)
@ -1439,12 +1440,34 @@ impl LockedDatabase {
bail!("can't delete dir referenced by stream {}", id);
}
}
// TODO: remove/update metadata stored in the directory? at present this will have to
// be manually deleted before the dir can be reused.
if self.conn.execute("delete from sample_file_dir where id = ?", &[&dir_id])? != 1 {
bail!("no such dir {} to remove", dir_id);
let mut d = match self.sample_file_dirs_by_id.entry(dir_id) {
::std::collections::btree_map::Entry::Occupied(e) => e,
_ => bail!("no such dir {} to remove", dir_id),
};
if !d.get().garbage.is_empty() {
bail!("must collect garbage before deleting directory {}", d.get().path);
}
self.sample_file_dirs_by_id.remove(&dir_id).expect("sample file dir should exist!");
let dir = match d.get_mut().dir.take() {
None => dir::SampleFileDir::open(&d.get().path, &d.get().meta(&self.uuid))?,
Some(arc) => match Arc::strong_count(&arc) {
1 => {
d.get_mut().dir = Some(arc); // put it back.
bail!("can't delete in-use directory {}", dir_id);
},
_ => arc,
},
};
if !dir::SampleFileDir::is_empty(&d.get().path)? {
bail!("Can't delete sample file directory {} which still has files", &d.get().path);
}
let mut meta = d.get().meta(&self.uuid);
meta.in_progress_open = mem::replace(&mut meta.last_complete_open,
::protobuf::singular::SingularPtrField::none());
dir.write_meta(&meta)?;
if self.conn.execute("delete from sample_file_dir where id = ?", &[&dir_id])? != 1 {
bail!("missing database row for dir {}", dir_id);
}
d.remove_entry();
Ok(())
}

17
db/dir.rs
View File

@ -228,11 +228,26 @@ impl SampleFileDir {
if old_meta.last_complete_open.is_some() {
bail!("Can't create dir at path {}: is already in use:\n{:?}", path, old_meta);
}
if !SampleFileDir::is_empty(path)? {
bail!("Can't create dir at path {} with existing files", path);
}
s.write_meta(db_meta)?;
Ok(s)
}
/// Determines if the directory is empty, aside form metadata.
pub(crate) fn is_empty(path: &str) -> Result<bool, Error> {
for e in fs::read_dir(path)? {
let e = e?;
match e.file_name().as_bytes() {
b"." | b".." => continue,
b"meta" | b"meta-tmp" => continue, // existing metadata is fine.
_ => return Ok(false),
}
}
Ok(true)
}
fn open_self(path: &str, create: bool) -> Result<Arc<SampleFileDir>, Error> {
let fd = Fd::open(path, create)
.map_err(|e| format_err!("unable to open sample file dir {}: {}", path, e))?;

4
db/schema.proto
View File

@ -63,7 +63,9 @@ message DirMeta {
}
// The last open that was known to be recorded in the database as completed.
// Absent if this has never happened.
// Absent if this has never happened. Note this can backtrack in exactly one
// scenario: when deleting the directory, after all associated files have
// been deleted, last_complete_open can be moved to in_progress_open.
Open last_complete_open = 3;
// The last run which is in progress, if different from last_complete_open.