fusefrontend: add fallocate support
Mode=0 (default) and mode=1 (keep size) are supported. The patch includes test cases and the whole thing passed xfstests. Fixes https://github.com/rfjakob/gocryptfs/issues/1 .
This commit is contained in:
Jakob Unterwurzacher
parent
04ad063515
commit
54470baa23
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@ -208,8 +208,6 @@ func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus
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return fuse.ReadResultData(out), status
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}
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const FALLOC_FL_KEEP_SIZE = 0x01
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// doWrite - encrypt "data" and write it to plaintext offset "off"
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//
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// Arguments do not have to be block-aligned, read-modify-write is
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@ -4,6 +4,7 @@ package fusefrontend
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// i.e. ftruncate and fallocate
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import (
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"log"
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"sync"
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"syscall"
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@ -12,17 +13,78 @@ import (
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"github.com/rfjakob/gocryptfs/internal/tlog"
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)
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const FALLOC_DEFAULT = 0x00
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const FALLOC_FL_KEEP_SIZE = 0x01
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// Only warn once
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var allocateWarnOnce sync.Once
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// Allocate - FUSE call, fallocate(2)
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// This is not implemented yet in gocryptfs, but it is neither in EncFS. This
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// suggests that the user demand is low.
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// Allocate - FUSE call for fallocate(2)
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//
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// mode=FALLOC_FL_KEEP_SIZE is implemented directly.
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//
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// mode=FALLOC_DEFAULT is implemented as a two-step process:
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//
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// (1) Allocate the space using FALLOC_FL_KEEP_SIZE
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// (2) Set the file size using ftruncate (via truncateGrowFile)
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//
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// This allows us to reuse the file grow mechanics from Truncate as they are
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// complicated and hard to get right.
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//
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// Other modes (hole punching, zeroing) are not supported.
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func (f *file) Allocate(off uint64, sz uint64, mode uint32) fuse.Status {
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allocateWarnOnce.Do(func() {
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tlog.Warn.Printf("fallocate(2) is not supported, returning ENOSYS - see https://github.com/rfjakob/gocryptfs/issues/1")
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})
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return fuse.ENOSYS
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if mode != FALLOC_DEFAULT && mode != FALLOC_FL_KEEP_SIZE {
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f := func() {
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tlog.Warn.Print("fallocate: only mode 0 (default) and 1 (keep size) are supported")
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}
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allocateWarnOnce.Do(f)
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return fuse.Status(syscall.EOPNOTSUPP)
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}
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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if f.released {
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return fuse.EBADF
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}
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wlock.lock(f.ino)
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defer wlock.unlock(f.ino)
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blocks := f.contentEnc.ExplodePlainRange(off, sz)
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firstBlock := blocks[0]
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lastBlock := blocks[len(blocks)-1]
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// Step (1): Allocate the space the user wants using FALLOC_FL_KEEP_SIZE.
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// This will fill file holes and/or allocate additional space past the end of
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// the file.
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cipherOff := firstBlock.BlockCipherOff()
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cipherSz := lastBlock.BlockCipherOff() - cipherOff +
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f.contentEnc.PlainSizeToCipherSize(lastBlock.Skip+lastBlock.Length)
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err := syscall.Fallocate(f.intFd(), FALLOC_FL_KEEP_SIZE, int64(cipherOff), int64(cipherSz))
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tlog.Debug.Printf("Allocate off=%d sz=%d mode=%x cipherOff=%d cipherSz=%d\n",
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off, sz, mode, cipherOff, cipherSz)
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if err != nil {
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return fuse.ToStatus(err)
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}
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if mode == FALLOC_FL_KEEP_SIZE {
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// The user did not want to change the apparent size. We are done.
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return fuse.OK
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}
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// Step (2): Grow the apparent file size
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// We need the old file size to determine if we are growing the file at all.
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newPlainSz := off + sz
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oldPlainSz, err := f.statPlainSize()
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if err != nil {
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return fuse.ToStatus(err)
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}
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if newPlainSz <= oldPlainSz {
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// The new size is smaller (or equal). Fallocate with mode = 0 never
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// truncates a file, so we are done.
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return fuse.OK
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}
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// The file grows. The space has already been allocated in (1), so what is
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// left to do is to pad the first and last block and call truncate.
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// truncateGrowFile does just that.
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return f.truncateGrowFile(oldPlainSz, newPlainSz)
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}
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// Truncate - FUSE call
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@ -50,13 +112,10 @@ func (f *file) Truncate(newSize uint64) fuse.Status {
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}
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// We need the old file size to determine if we are growing or shrinking
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// the file
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fi, err := f.fd.Stat()
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oldSize, err := f.statPlainSize()
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if err != nil {
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tlog.Warn.Printf("ino%d fh%d: Truncate: Fstat failed: %v", f.ino, f.intFd(), err)
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return fuse.ToStatus(err)
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}
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oldSize := f.contentEnc.CipherSizeToPlainSize(uint64(fi.Size()))
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{
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} else {
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oldB := float32(oldSize) / float32(f.contentEnc.PlainBS())
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newB := float32(newSize) / float32(f.contentEnc.PlainBS())
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tlog.Debug.Printf("ino%d: FUSE Truncate from %.2f to %.2f blocks (%d to %d bytes)", f.ino, oldB, newB, oldSize, newSize)
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@ -67,31 +126,7 @@ func (f *file) Truncate(newSize uint64) fuse.Status {
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}
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// File grows
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if newSize > oldSize {
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// File was empty, create new header
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if oldSize == 0 {
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err = f.createHeader()
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if err != nil {
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return fuse.ToStatus(err)
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}
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}
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// New blocks to add
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addBlocks := f.contentEnc.ExplodePlainRange(oldSize, newSize-oldSize)
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if len(addBlocks) >= 2 {
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f.zeroPad(oldSize)
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}
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lastBlock := addBlocks[len(addBlocks)-1]
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if lastBlock.IsPartial() {
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off := lastBlock.BlockPlainOff()
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_, status := f.doWrite(make([]byte, lastBlock.Length), int64(off+lastBlock.Skip))
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return status
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} else {
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off := lastBlock.BlockCipherOff()
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err = syscall.Ftruncate(f.intFd(), int64(off+f.contentEnc.CipherBS()))
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if err != nil {
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tlog.Warn.Printf("Truncate: grow Ftruncate returned error: %v", err)
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}
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return fuse.ToStatus(err)
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}
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return f.truncateGrowFile(oldSize, newSize)
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} else {
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// File shrinks
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blockNo := f.contentEnc.PlainOffToBlockNo(newSize)
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@ -121,3 +156,53 @@ func (f *file) Truncate(newSize uint64) fuse.Status {
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return fuse.OK
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}
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}
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// statPlainSize stats the file and returns the plaintext size
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func (f *file) statPlainSize() (uint64, error) {
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fi, err := f.fd.Stat()
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if err != nil {
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tlog.Warn.Printf("ino%d fh%d: statPlainSize: %v", f.ino, f.intFd(), err)
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return 0, err
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}
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cipherSz := uint64(fi.Size())
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plainSz := uint64(f.contentEnc.CipherSizeToPlainSize(cipherSz))
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return plainSz, nil
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}
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// truncateGrowFile extends a file using seeking or ftruncate performing RMW on
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// the first and last block as neccessary. New blocks in the middle become
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// file holes unless they have been fallocate()'d beforehand.
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func (f *file) truncateGrowFile(oldPlainSz uint64, newPlainSz uint64) fuse.Status {
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if newPlainSz <= oldPlainSz {
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log.Panicf("BUG: newSize=%d <= oldSize=%d", newPlainSz, oldPlainSz)
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}
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var err error
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// File was empty, create new header
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if oldPlainSz == 0 {
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err = f.createHeader()
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if err != nil {
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return fuse.ToStatus(err)
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}
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}
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// New blocks to add
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addBlocks := f.contentEnc.ExplodePlainRange(oldPlainSz, newPlainSz-oldPlainSz)
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if oldPlainSz > 0 && len(addBlocks) >= 2 {
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// Zero-pad the first block (unless the first block is also the last block)
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f.zeroPad(oldPlainSz)
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}
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lastBlock := addBlocks[len(addBlocks)-1]
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if lastBlock.IsPartial() {
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// Write at the new end of the file. The seek implicitly grows the file
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// (creates a file hole) and doWrite() takes care of RMW.
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off := lastBlock.BlockPlainOff()
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_, status := f.doWrite(make([]byte, lastBlock.Length), int64(off+lastBlock.Skip))
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return status
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} else {
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off := lastBlock.BlockCipherOff()
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err = syscall.Ftruncate(f.intFd(), int64(off+f.contentEnc.CipherBS()))
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if err != nil {
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tlog.Warn.Printf("Truncate: grow Ftruncate returned error: %v", err)
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}
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return fuse.ToStatus(err)
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}
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}
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@ -124,26 +124,26 @@ func TestTruncate(t *testing.T) {
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// Grow to two blocks
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file.Truncate(7000)
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test_helpers.VerifySize(t, fn, 7000)
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if test_helpers.Md5fn(fn) != "95d4ec7038e3e4fdbd5f15c34c3f0b34" {
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t.Errorf("wrong content")
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if md5 := test_helpers.Md5fn(fn); md5 != "95d4ec7038e3e4fdbd5f15c34c3f0b34" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Shrink - needs RMW
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file.Truncate(6999)
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test_helpers.VerifySize(t, fn, 6999)
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if test_helpers.Md5fn(fn) != "35fd15873ec6c35380064a41b9b9683b" {
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t.Errorf("wrong content")
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if md5 := test_helpers.Md5fn(fn); md5 != "35fd15873ec6c35380064a41b9b9683b" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Shrink to one partial block
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file.Truncate(465)
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test_helpers.VerifySize(t, fn, 465)
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if test_helpers.Md5fn(fn) != "a1534d6e98a6b21386456a8f66c55260" {
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t.Errorf("wrong content")
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if md5 := test_helpers.Md5fn(fn); md5 != "a1534d6e98a6b21386456a8f66c55260" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Grow to exactly one block
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file.Truncate(4096)
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test_helpers.VerifySize(t, fn, 4096)
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if test_helpers.Md5fn(fn) != "620f0b67a91f7f74151bc5be745b7110" {
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t.Errorf("wrong content")
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if md5 := test_helpers.Md5fn(fn); md5 != "620f0b67a91f7f74151bc5be745b7110" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Truncate to zero
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file.Truncate(0)
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@ -153,25 +153,133 @@ func TestTruncate(t *testing.T) {
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sz = 10 * 1024 * 1024
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file.Truncate(int64(sz))
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test_helpers.VerifySize(t, fn, sz)
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if test_helpers.Md5fn(fn) != "f1c9645dbc14efddc7d8a322685f26eb" {
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t.Errorf("wrong content")
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if md5 := test_helpers.Md5fn(fn); md5 != "f1c9645dbc14efddc7d8a322685f26eb" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Grow to 10MB + 100B (partial block on the end)
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sz = 10*1024*1024 + 100
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file.Truncate(int64(sz))
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test_helpers.VerifySize(t, fn, sz)
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if test_helpers.Md5fn(fn) != "c23ea79b857b91a7ff07c6ecf185f1ca" {
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t.Errorf("wrong content")
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if md5 := test_helpers.Md5fn(fn); md5 != "c23ea79b857b91a7ff07c6ecf185f1ca" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Grow to 20MB (creates file holes, partial block on the front)
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sz = 20 * 1024 * 1024
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file.Truncate(int64(sz))
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test_helpers.VerifySize(t, fn, sz)
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if test_helpers.Md5fn(fn) != "8f4e33f3dc3e414ff94e5fb6905cba8c" {
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t.Errorf("wrong content")
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if md5 := test_helpers.Md5fn(fn); md5 != "8f4e33f3dc3e414ff94e5fb6905cba8c" {
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t.Errorf("Wrong md5 %s", md5)
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}
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}
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const FALLOC_DEFAULT = 0x00
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const FALLOC_FL_KEEP_SIZE = 0x01
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func TestFallocate(t *testing.T) {
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fn := test_helpers.DefaultPlainDir + "/fallocate"
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file, err := os.Create(fn)
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if err != nil {
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t.FailNow()
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}
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var nBlocks int64
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fd := int(file.Fd())
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_, nBlocks = test_helpers.Du(t, fd)
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if nBlocks != 0 {
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t.Fatalf("Empty file has %d blocks", nBlocks)
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}
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// Allocate 30 bytes, keep size
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// gocryptfs || (0 blocks)
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// ext4 | d | (1 block)
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err = syscall.Fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 30)
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if err != nil {
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t.Error(err)
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}
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_, nBlocks = test_helpers.Du(t, fd)
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if want := 1; nBlocks/8 != int64(want) {
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t.Errorf("Expected %d 4k block(s), got %d", want, nBlocks/8)
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}
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test_helpers.VerifySize(t, fn, 0)
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// Three ciphertext blocks. The middle one should be a file hole.
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// gocryptfs | h | h | d| (1 block)
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// ext4 | d | h | d | (2 blocks)
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// (Note that gocryptfs blocks are slightly bigger than the ext4 blocks,
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// but the last one is partial)
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err = file.Truncate(9000)
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if err != nil {
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t.Fatal(err)
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}
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_, nBlocks = test_helpers.Du(t, fd)
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if want := 2; nBlocks/8 != int64(want) {
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t.Errorf("Expected %d 4k block(s), got %d", want, nBlocks/8)
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}
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if md5 := test_helpers.Md5fn(fn); md5 != "5420afa22f6423a9f59e669540656bb4" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Allocate the whole file space
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// gocryptfs | h | h | d| (1 block)
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// ext4 | d | d | d | (3 blocks
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err = syscall.Fallocate(fd, FALLOC_DEFAULT, 0, 9000)
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if err != nil {
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t.Fatal(err)
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}
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_, nBlocks = test_helpers.Du(t, fd)
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if want := 3; nBlocks/8 != int64(want) {
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t.Errorf("Expected %d 4k block(s), got %d", want, nBlocks/8)
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}
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// Neither apparent size nor content should have changed
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test_helpers.VerifySize(t, fn, 9000)
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if md5 := test_helpers.Md5fn(fn); md5 != "5420afa22f6423a9f59e669540656bb4" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Partial block on the end. The first ext4 block is dirtied by the header.
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// gocryptfs | h | h | d| (1 block)
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// ext4 | d | h | d | (2 blocks)
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file.Truncate(0)
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file.Truncate(9000)
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_, nBlocks = test_helpers.Du(t, fd)
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if want := 2; nBlocks/8 != int64(want) {
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t.Errorf("Expected %d 4k block(s), got %d", want, nBlocks/8)
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}
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// Allocate 10 bytes in the second block
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// gocryptfs | h | h | d| (1 block)
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// ext4 | d | d | d | (2 blocks)
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syscall.Fallocate(fd, FALLOC_DEFAULT, 5000, 10)
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_, nBlocks = test_helpers.Du(t, fd)
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if want := 3; nBlocks/8 != int64(want) {
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t.Errorf("Expected %d 4k block(s), got %d", want, nBlocks/8)
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}
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// Neither apparent size nor content should have changed
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test_helpers.VerifySize(t, fn, 9000)
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if md5 := test_helpers.Md5fn(fn); md5 != "5420afa22f6423a9f59e669540656bb4" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Grow the file to 4 blocks
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// gocryptfs | h | h | d |d| (2 blocks)
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// ext4 | d | d | d | d | (3 blocks)
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syscall.Fallocate(fd, FALLOC_DEFAULT, 15000, 10)
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_, nBlocks = test_helpers.Du(t, fd)
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if want := 4; nBlocks/8 != int64(want) {
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t.Errorf("Expected %d 4k block(s), got %d", want, nBlocks/8)
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}
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test_helpers.VerifySize(t, fn, 15010)
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if md5 := test_helpers.Md5fn(fn); md5 != "c4c44c7a41ab7798a79d093eb44f99fc" {
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t.Errorf("Wrong md5 %s", md5)
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}
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// Shrinking a file using fallocate should have no effect
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for _, off := range []int64{0, 10, 2000, 5000} {
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for _, sz := range []int64{0, 1, 42, 6000} {
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syscall.Fallocate(fd, FALLOC_DEFAULT, off, sz)
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test_helpers.VerifySize(t, fn, 15010)
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if md5 := test_helpers.Md5fn(fn); md5 != "c4c44c7a41ab7798a79d093eb44f99fc" {
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t.Errorf("Wrong md5 %s", md5)
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}
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}
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}
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// Cleanup
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syscall.Unlink(fn)
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}
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func TestAppend(t *testing.T) {
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fn := test_helpers.DefaultPlainDir + "/append"
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file, err := os.Create(fn)
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@ -283,3 +283,14 @@ func VerifyExistence(path string) bool {
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}
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return false
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}
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||||
|
||||
// Du returns the disk usage of the file "fd" points to, in bytes.
|
||||
// Same as "du --block-size=1".
|
||||
func Du(t *testing.T, fd int) (nBytes int64, nBlocks int64) {
|
||||
var st syscall.Stat_t
|
||||
err := syscall.Fstat(fd, &st)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
return st.Blocks * st.Blksize, st.Blocks
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue