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authorJakob Unterwurzacher2020-08-16 12:48:16 +0200
committerJakob Unterwurzacher2020-08-16 12:50:33 +0200
commitee5ab1cc29c6f5ff6061a88b742d5ff88de40802 (patch)
tree023406f3b09208a145d8cec8ebe81d9ebd62e09d /internal/fusefrontend/file2_allocate_truncate.go
parent94e8fc12ea5756a130e7ac9ed67ddd519b5f3a22 (diff)
v2api: rename "File2" to just "File"
Rename the symbols and the files.
Diffstat (limited to 'internal/fusefrontend/file2_allocate_truncate.go')
-rw-r--r--internal/fusefrontend/file2_allocate_truncate.go218
1 files changed, 0 insertions, 218 deletions
diff --git a/internal/fusefrontend/file2_allocate_truncate.go b/internal/fusefrontend/file2_allocate_truncate.go
deleted file mode 100644
index cdda974..0000000
--- a/internal/fusefrontend/file2_allocate_truncate.go
+++ /dev/null
@@ -1,218 +0,0 @@
-package fusefrontend
-
-// FUSE operations Truncate and Allocate on file handles
-// i.e. ftruncate and fallocate
-
-import (
- "context"
- "log"
- "sync"
- "syscall"
-
- "github.com/hanwen/go-fuse/v2/fs"
-
- "github.com/rfjakob/gocryptfs/internal/syscallcompat"
- "github.com/rfjakob/gocryptfs/internal/tlog"
-)
-
-// FALLOC_DEFAULT is a "normal" fallocate operation
-const FALLOC_DEFAULT = 0x00
-
-// FALLOC_FL_KEEP_SIZE allocates disk space while not modifying the file size
-const FALLOC_FL_KEEP_SIZE = 0x01
-
-// Only warn once
-var allocateWarnOnce sync.Once
-
-// Allocate - FUSE call for fallocate(2)
-//
-// mode=FALLOC_FL_KEEP_SIZE is implemented directly.
-//
-// mode=FALLOC_DEFAULT is implemented as a two-step process:
-//
-// (1) Allocate the space using FALLOC_FL_KEEP_SIZE
-// (2) Set the file size using ftruncate (via truncateGrowFile)
-//
-// This allows us to reuse the file grow mechanics from Truncate as they are
-// complicated and hard to get right.
-//
-// Other modes (hole punching, zeroing) are not supported.
-func (f *File2) Allocate(ctx context.Context, off uint64, sz uint64, mode uint32) syscall.Errno {
- if mode != FALLOC_DEFAULT && mode != FALLOC_FL_KEEP_SIZE {
- f := func() {
- tlog.Info.Printf("fallocate: only mode 0 (default) and 1 (keep size) are supported")
- }
- allocateWarnOnce.Do(f)
- return syscall.EOPNOTSUPP
- }
-
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
- if f.released {
- return syscall.EBADF
- }
- f.fileTableEntry.ContentLock.Lock()
- defer f.fileTableEntry.ContentLock.Unlock()
-
- blocks := f.contentEnc.ExplodePlainRange(off, sz)
- firstBlock := blocks[0]
- lastBlock := blocks[len(blocks)-1]
-
- // Step (1): Allocate the space the user wants using FALLOC_FL_KEEP_SIZE.
- // This will fill file holes and/or allocate additional space past the end of
- // the file.
- cipherOff := firstBlock.BlockCipherOff()
- cipherSz := lastBlock.BlockCipherOff() - cipherOff +
- f.contentEnc.BlockOverhead() + lastBlock.Skip + lastBlock.Length
- err := syscallcompat.Fallocate(f.intFd(), FALLOC_FL_KEEP_SIZE, int64(cipherOff), int64(cipherSz))
- tlog.Debug.Printf("Allocate off=%d sz=%d mode=%x cipherOff=%d cipherSz=%d\n",
- off, sz, mode, cipherOff, cipherSz)
- if err != nil {
- return fs.ToErrno(err)
- }
- if mode == FALLOC_FL_KEEP_SIZE {
- // The user did not want to change the apparent size. We are done.
- return 0
- }
- // Step (2): Grow the apparent file size
- // We need the old file size to determine if we are growing the file at all.
- newPlainSz := off + sz
- oldPlainSz, err := f.statPlainSize()
- if err != nil {
- return fs.ToErrno(err)
- }
- if newPlainSz <= oldPlainSz {
- // The new size is smaller (or equal). Fallocate with mode = 0 never
- // truncates a file, so we are done.
- return 0
- }
- // The file grows. The space has already been allocated in (1), so what is
- // left to do is to pad the first and last block and call truncate.
- // truncateGrowFile does just that.
- return f.truncateGrowFile(oldPlainSz, newPlainSz)
-}
-
-// truncate - called from Setattr.
-func (f *File2) truncate(newSize uint64) (errno syscall.Errno) {
- var err error
- // Common case first: Truncate to zero
- if newSize == 0 {
- err = syscall.Ftruncate(int(f.fd.Fd()), 0)
- if err != nil {
- tlog.Warn.Printf("ino%d fh%d: Ftruncate(fd, 0) returned error: %v", f.qIno.Ino, f.intFd(), err)
- return fs.ToErrno(err)
- }
- // Truncate to zero kills the file header
- f.fileTableEntry.ID = nil
- return 0
- }
- // We need the old file size to determine if we are growing or shrinking
- // the file
- oldSize, err := f.statPlainSize()
- if err != nil {
- return fs.ToErrno(err)
- }
-
- oldB := float32(oldSize) / float32(f.contentEnc.PlainBS())
- newB := float32(newSize) / float32(f.contentEnc.PlainBS())
- tlog.Debug.Printf("ino%d: FUSE Truncate from %.2f to %.2f blocks (%d to %d bytes)", f.qIno.Ino, oldB, newB, oldSize, newSize)
-
- // File size stays the same - nothing to do
- if newSize == oldSize {
- return 0
- }
- // File grows
- if newSize > oldSize {
- return f.truncateGrowFile(oldSize, newSize)
- }
-
- // File shrinks
- blockNo := f.contentEnc.PlainOffToBlockNo(newSize)
- cipherOff := f.contentEnc.BlockNoToCipherOff(blockNo)
- plainOff := f.contentEnc.BlockNoToPlainOff(blockNo)
- lastBlockLen := newSize - plainOff
- var data []byte
- if lastBlockLen > 0 {
- data, errno = f.doRead(nil, plainOff, lastBlockLen)
- if errno != 0 {
- tlog.Warn.Printf("Truncate: shrink doRead returned error: %v", err)
- return errno
- }
- }
- // Truncate down to the last complete block
- err = syscall.Ftruncate(int(f.fd.Fd()), int64(cipherOff))
- if err != nil {
- tlog.Warn.Printf("Truncate: shrink Ftruncate returned error: %v", err)
- return fs.ToErrno(err)
- }
- // Append partial block
- if lastBlockLen > 0 {
- _, status := f.doWrite(data, int64(plainOff))
- return status
- }
- return 0
-}
-
-// statPlainSize stats the file and returns the plaintext size
-func (f *File2) statPlainSize() (uint64, error) {
- fi, err := f.fd.Stat()
- if err != nil {
- tlog.Warn.Printf("ino%d fh%d: statPlainSize: %v", f.qIno.Ino, f.intFd(), err)
- return 0, err
- }
- cipherSz := uint64(fi.Size())
- plainSz := uint64(f.contentEnc.CipherSizeToPlainSize(cipherSz))
- return plainSz, nil
-}
-
-// truncateGrowFile extends a file using seeking or ftruncate performing RMW on
-// the first and last block as necessary. New blocks in the middle become
-// file holes unless they have been fallocate()'d beforehand.
-func (f *File2) truncateGrowFile(oldPlainSz uint64, newPlainSz uint64) syscall.Errno {
- if newPlainSz <= oldPlainSz {
- log.Panicf("BUG: newSize=%d <= oldSize=%d", newPlainSz, oldPlainSz)
- }
- newEOFOffset := newPlainSz - 1
- if oldPlainSz > 0 {
- n1 := f.contentEnc.PlainOffToBlockNo(oldPlainSz - 1)
- n2 := f.contentEnc.PlainOffToBlockNo(newEOFOffset)
- // The file is grown within one block, no need to pad anything.
- // Write a single zero to the last byte and let doWrite figure out the RMW.
- if n1 == n2 {
- buf := make([]byte, 1)
- _, errno := f.doWrite(buf, int64(newEOFOffset))
- return errno
- }
- }
- // The truncate creates at least one new block.
- //
- // Make sure the old last block is padded to the block boundary. This call
- // is a no-op if it is already block-aligned.
- errno := f.zeroPad(oldPlainSz)
- if errno != 0 {
- return errno
- }
- // The new size is block-aligned. In this case we can do everything ourselves
- // and avoid the call to doWrite.
- if newPlainSz%f.contentEnc.PlainBS() == 0 {
- // The file was empty, so it did not have a header. Create one.
- if oldPlainSz == 0 {
- id, err := f.createHeader()
- if err != nil {
- return fs.ToErrno(err)
- }
- f.fileTableEntry.ID = id
- }
- cSz := int64(f.contentEnc.PlainSizeToCipherSize(newPlainSz))
- err := syscall.Ftruncate(f.intFd(), cSz)
- if err != nil {
- tlog.Warn.Printf("Truncate: grow Ftruncate returned error: %v", err)
- }
- return fs.ToErrno(err)
- }
- // The new size is NOT aligned, so we need to write a partial block.
- // Write a single zero to the last byte and let doWrite figure it out.
- buf := make([]byte, 1)
- _, errno = f.doWrite(buf, int64(newEOFOffset))
- return errno
-}