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This commit is contained in:
Eelco Dolstra 2008-03-08 20:52:00 +00:00
parent 10c6e2a629
commit a7154c5b14
1 changed files with 26 additions and 15 deletions
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41
src/libstore/local-store.cc
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@ -201,12 +201,15 @@ static Path tmpFileForAtomicUpdate(const Path & path)
} }
static void appendReferrer(const Path & from, const Path & to) static void appendReferrer(const Path & from, const Path & to, bool lock)
{ {
Path referrersFile = referrersFileFor(from); Path referrersFile = referrersFileFor(from);
PathLocks referrersLock(singleton<PathSet, Path>(referrersFile)); PathLocks referrersLock;
referrersLock.setDeletion(true); if (lock) {
referrersLock.lockPaths(singleton<PathSet, Path>(referrersFile));
referrersLock.setDeletion(true);
}
AutoCloseFD fd = open(referrersFile.c_str(), O_WRONLY | O_APPEND | O_CREAT, 0666); AutoCloseFD fd = open(referrersFile.c_str(), O_WRONLY | O_APPEND | O_CREAT, 0666);
if (fd == -1) throw SysError(format("opening file `%1%'") % referrersFile); if (fd == -1) throw SysError(format("opening file `%1%'") % referrersFile);
@ -279,20 +282,24 @@ void LocalStore::registerValidPath(const ValidPathInfo & info)
ValidPathInfo oldInfo; ValidPathInfo oldInfo;
if (pathExists(infoFile)) oldInfo = queryPathInfo(info.path); if (pathExists(infoFile)) oldInfo = queryPathInfo(info.path);
/* Note that it's possible for infoFile to already exist. !!! /* Note that it's possible for infoFile to already exist. */
check what happens in case of repeated registrations */
// !!! acquire PathLock on infoFile here?
/* Acquire a lock on each referrer file. This prevents those
paths from being invalidated. (It would be a violation of the
store invariants if we registered info.path as valid while some
of its references are invalid.) NB: there can be no deadlock
here since we're acquiring the locks in sorted order. */
PathSet lockNames;
foreach (PathSet::const_iterator, i, info.references)
if (*i != info.path) lockNames.insert(referrersFileFor(*i));
PathLocks referrerLocks(lockNames);
referrerLocks.setDeletion(true);
string refs; string refs;
for (PathSet::const_iterator i = info.references.begin(); foreach (PathSet::const_iterator, i, info.references) {
i != info.references.end(); ++i)
{
if (!refs.empty()) refs += " "; if (!refs.empty()) refs += " ";
refs += *i; refs += *i;
/* !!! locking: what if *i becomes invalid between here and
`path' becoming valid? */
if (*i != info.path && !isValidPath(*i)) if (*i != info.path && !isValidPath(*i))
throw Error(format("cannot register `%1%' as valid, because its reference `%2%' isn't valid") throw Error(format("cannot register `%1%' as valid, because its reference `%2%' isn't valid")
% info.path % *i); % info.path % *i);
@ -304,7 +311,7 @@ void LocalStore::registerValidPath(const ValidPathInfo & info)
to separate it from the previous entry. It's not suffixed to separate it from the previous entry. It's not suffixed
to deal with interrupted partial writes to this file. */ to deal with interrupted partial writes to this file. */
if (oldInfo.references.find(*i) == oldInfo.references.end()) if (oldInfo.references.find(*i) == oldInfo.references.end())
appendReferrer(*i, info.path); appendReferrer(*i, info.path, false);
} }
string s = (format( string s = (format(
@ -844,9 +851,13 @@ void LocalStore::deleteFromStore(const Path & path, unsigned long long & bytesFr
assertStorePath(path); assertStorePath(path);
if (isValidPath(path)) { if (isValidPath(path)) {
/* Acquire a lock on the referrers file to prevent new
referrers to this path from appearing while we're deleting
it. */
PathLocks referrersLock(singleton<PathSet, Path>(referrersFileFor(path)));
referrersLock.setDeletion(true);
PathSet referrers; queryReferrers(path, referrers); PathSet referrers; queryReferrers(path, referrers);
referrers.erase(path); /* ignore self-references */ referrers.erase(path); /* ignore self-references */
/* !!! check: can a new referrer appear now? */
if (!referrers.empty()) if (!referrers.empty())
throw PathInUse(format("cannot delete path `%1%' because it is in use by `%2%'") throw PathInUse(format("cannot delete path `%1%' because it is in use by `%2%'")
% path % showPaths(referrers)); % path % showPaths(referrers));
@ -896,7 +907,7 @@ void LocalStore::verifyStore(bool checkContents)
if (referrersCache[*j].find(*i) == referrersCache[*j].end()) { if (referrersCache[*j].find(*i) == referrersCache[*j].end()) {
printMsg(lvlError, format("adding missing referrer mapping from `%1%' to `%2%'") printMsg(lvlError, format("adding missing referrer mapping from `%1%' to `%2%'")
% *j % *i); % *j % *i);
appendReferrer(*j, *i); appendReferrer(*j, *i, true);
} }
if (validPaths.find(*j) == validPaths.end()) { if (validPaths.find(*j) == validPaths.end()) {
printMsg(lvlError, format("incomplete closure: `%1%' needs missing `%2%'") printMsg(lvlError, format("incomplete closure: `%1%' needs missing `%2%'")