Flush before Fsync()/Sync()

Summary: Calling Fsync()/Sync() on a file should give the guarantee that whatever you written to the file is now persisted. This is currently not the case, since we might have some data left in application cache as we do Fsync()/Sync(). For example, BuildTable() calls Fsync() without the flush, assuming all sst data is now persisted, but it's actually not. This may result in big inconsistencies.

Test Plan: no test

Reviewers: sdong, dhruba, haobo, ljin, yhchiang

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18159
This commit is contained in:
Igor Canadi 2014-04-21 17:45:04 -07:00
parent ba16c1f410
commit c2da9e5997

View File

@ -761,6 +761,10 @@ class PosixWritableFile : public WritableFile {
}
virtual Status Sync() {
Status s = Flush();
if (!s.ok()) {
return s;
}
TEST_KILL_RANDOM(rocksdb_kill_odds);
if (pending_sync_ && fdatasync(fd_) < 0) {
return IOError(filename_, errno);
@ -771,6 +775,10 @@ class PosixWritableFile : public WritableFile {
}
virtual Status Fsync() {
Status s = Flush();
if (!s.ok()) {
return s;
}
TEST_KILL_RANDOM(rocksdb_kill_odds);
if (pending_fsync_ && fsync(fd_) < 0) {
return IOError(filename_, errno);