b96e3ee271
A few places have called tlog.Warn.Print, which directly calls into log.Logger due to embedding, losing all features of tlog. Stop embedding log.Logger to make sure the internal functions cannot be called accidentially and fix (several!) instances that did.
230 lines
7.3 KiB
Go
230 lines
7.3 KiB
Go
package fusefrontend
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// FUSE operations Truncate and Allocate on file handles
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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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"github.com/hanwen/go-fuse/fuse"
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"github.com/rfjakob/gocryptfs/internal/syscallcompat"
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"github.com/rfjakob/gocryptfs/internal/tlog"
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)
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// FALLOC_DEFAULT is a "normal" fallocate operation
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const FALLOC_DEFAULT = 0x00
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// FALLOC_FL_KEEP_SIZE allocates disk space while not modifying the file size
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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 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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if mode != FALLOC_DEFAULT && mode != FALLOC_FL_KEEP_SIZE {
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f := func() {
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tlog.Warn.Printf("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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f.fileTableEntry.ContentLock.Lock()
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defer f.fileTableEntry.ContentLock.Unlock()
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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 := syscallcompat.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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func (f *file) Truncate(newSize uint64) fuse.Status {
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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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// The file descriptor has been closed concurrently.
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tlog.Warn.Printf("ino%d fh%d: Truncate on released file", f.qIno.Ino, f.intFd())
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return fuse.EBADF
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}
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f.fileTableEntry.ContentLock.Lock()
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defer f.fileTableEntry.ContentLock.Unlock()
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var err error
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// Common case first: Truncate to zero
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if newSize == 0 {
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err = syscall.Ftruncate(int(f.fd.Fd()), 0)
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if err != nil {
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tlog.Warn.Printf("ino%d fh%d: Ftruncate(fd, 0) returned error: %v", f.qIno.Ino, f.intFd(), err)
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return fuse.ToStatus(err)
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}
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// Truncate to zero kills the file header
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f.fileTableEntry.HeaderLock.Lock()
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f.fileTableEntry.ID = nil
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f.fileTableEntry.HeaderLock.Unlock()
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return fuse.OK
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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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oldSize, 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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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.qIno.Ino, oldB, newB, oldSize, newSize)
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// File size stays the same - nothing to do
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if newSize == oldSize {
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return fuse.OK
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}
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// File grows
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if newSize > oldSize {
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return f.truncateGrowFile(oldSize, newSize)
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}
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// File shrinks
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blockNo := f.contentEnc.PlainOffToBlockNo(newSize)
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cipherOff := f.contentEnc.BlockNoToCipherOff(blockNo)
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plainOff := f.contentEnc.BlockNoToPlainOff(blockNo)
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lastBlockLen := newSize - plainOff
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var data []byte
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if lastBlockLen > 0 {
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var status fuse.Status
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data, status = f.doRead(nil, plainOff, lastBlockLen)
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if status != fuse.OK {
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tlog.Warn.Printf("Truncate: shrink doRead returned error: %v", err)
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return status
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}
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}
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// Truncate down to the last complete block
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err = syscall.Ftruncate(int(f.fd.Fd()), int64(cipherOff))
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if err != nil {
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tlog.Warn.Printf("Truncate: shrink Ftruncate returned error: %v", err)
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return fuse.ToStatus(err)
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}
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// Append partial block
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if lastBlockLen > 0 {
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_, status := f.doWrite(data, int64(plainOff))
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return status
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}
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return fuse.OK
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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.qIno.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 necessary. 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 n1 uint64
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if oldPlainSz > 0 {
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n1 = f.contentEnc.PlainOffToBlockNo(oldPlainSz - 1)
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}
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newEOFOffset := newPlainSz - 1
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n2 := f.contentEnc.PlainOffToBlockNo(newEOFOffset)
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// The file is grown within one block, no need to pad anything.
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// Write a single zero to the last byte and let doWrite figure out the RMW.
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if n1 == n2 {
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buf := make([]byte, 1)
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_, status := f.doWrite(buf, int64(newEOFOffset))
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return status
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}
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// The truncate creates at least one new block.
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//
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// Make sure the old last block is padded to the block boundary. This call
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// is a no-op if it is already block-aligned.
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f.zeroPad(oldPlainSz)
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// The new size is block-aligned. In this case we can do everything ourselves
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// and avoid the call to doWrite.
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if newPlainSz%f.contentEnc.PlainBS() == 0 {
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// The file was empty, so it did not have a header. Create one.
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if oldPlainSz == 0 {
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f.fileTableEntry.HeaderLock.Lock()
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defer f.fileTableEntry.HeaderLock.Unlock()
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id, 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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f.fileTableEntry.ID = id
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}
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cSz := int64(f.contentEnc.PlainSizeToCipherSize(newPlainSz))
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err := syscall.Ftruncate(f.intFd(), cSz)
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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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// The new size is NOT aligned, so we need to write a partial block.
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// Write a single zero to the last byte and let doWrite figure it out.
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buf := make([]byte, 1)
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_, status := f.doWrite(buf, int64(newEOFOffset))
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return status
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}
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