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authorJakob Unterwurzacher2017-03-18 16:01:50 +0100
committerJakob Unterwurzacher2017-03-18 16:18:00 +0100
commit00df0771e3dd9fba0992cbc9a7d347f25aff856a (patch)
tree62c7a234184413ffd8250579d0c7935aa2941553 /internal/fusefrontend/file.go
parent14038a1644f17f50b113a05d09a2a0a3b3e973b2 (diff)
serialize_reads: add read serialization logic
Due to kernel readahead, we usually get multiple read requests at the same time. These get submitted to the backing storage in random order, which is a problem if seeking is very expensive. Details: https://github.com/rfjakob/gocryptfs/issues/92
Diffstat (limited to 'internal/fusefrontend/file.go')
-rw-r--r--internal/fusefrontend/file.go11
1 files changed, 11 insertions, 0 deletions
diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go
index dac7510..b41f220 100644
--- a/internal/fusefrontend/file.go
+++ b/internal/fusefrontend/file.go
@@ -17,6 +17,7 @@ import (
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/rfjakob/gocryptfs/internal/contentenc"
+ "github.com/rfjakob/gocryptfs/internal/serialize_reads"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
@@ -176,6 +177,7 @@ func (f *file) doRead(off uint64, length uint64) ([]byte, fuse.Status) {
alignedOffset, alignedLength := blocks[0].JointCiphertextRange(blocks)
skip := blocks[0].Skip
tlog.Debug.Printf("JointCiphertextRange(%d, %d) -> %d, %d, %d", off, length, alignedOffset, alignedLength, skip)
+
ciphertext := make([]byte, int(alignedLength))
n, err := f.fd.ReadAt(ciphertext, int64(alignedOffset))
// We don't care if the file ID changes after we have read the data. Drop the lock.
@@ -224,8 +226,17 @@ func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus
return nil, fuse.EBADF
}
+ if f.fs.args.SerializeReads {
+ serialize_reads.Wait(off, len(buf))
+ }
+
+ fmt.Printf("%02d\n", off/131072)
out, status := f.doRead(uint64(off), uint64(len(buf)))
+ if f.fs.args.SerializeReads {
+ serialize_reads.Done()
+ }
+
if status == fuse.EIO {
tlog.Warn.Printf("ino%d: Read: returning EIO, offset=%d, length=%d", f.devIno.ino, len(buf), off)
}