diff options
| -rw-r--r-- | Documentation/MANPAGE.md | 18 | ||||
| -rw-r--r-- | cli_args.go | 6 | ||||
| -rw-r--r-- | internal/fusefrontend/args.go | 2 | ||||
| -rw-r--r-- | internal/fusefrontend/file.go | 30 | ||||
| -rw-r--r-- | internal/fusefrontend/fs.go | 4 | ||||
| -rw-r--r-- | mount.go | 1 |
6 files changed, 45 insertions, 16 deletions
diff --git a/Documentation/MANPAGE.md b/Documentation/MANPAGE.md index 9446f0b..aa40922 100644 --- a/Documentation/MANPAGE.md +++ b/Documentation/MANPAGE.md @@ -106,6 +106,22 @@ Options: : Allow mounting over non-empty directories. FUSE by default disallows this to prevent accidential shadowing of files. +**-noprealloc** +: Disable preallocation before writing. By default, gocryptfs + preallocates the space the next write will take using fallocate(2) + in mode FALLOC_FL_KEEP_SIZE. The preallocation makes sure it cannot + run out of space in the middle of the write, which would cause the + last 4kB block to be corrupt and unreadable. + + On ext4, preallocation is fast and does not cause a + noticeable performance hit. Unfortunately, on Btrfs, preallocation + is very slow, especially on rotational HDDs. The "-noprealloc" + option gives users the choice to trade robustness against + out-of-space errors for a massive speedup. + + For benchmarks and more details of the issue see + https://github.com/rfjakob/gocryptfs/issues/63 . + **-nosyslog** : Diagnostic messages are normally redirected to syslog once gocryptfs daemonizes. This option disables the redirection and messages will @@ -197,4 +213,4 @@ Mount an ecrypted view of joe's home directory using reverse mode: SEE ALSO ======== -fuse(8) +fuse(8) fallocate(2) diff --git a/cli_args.go b/cli_args.go index 5751f81..7301d9a 100644 --- a/cli_args.go +++ b/cli_args.go @@ -16,7 +16,8 @@ import ( type argContainer struct { debug, init, zerokey, fusedebug, openssl, passwd, fg, version, plaintextnames, quiet, nosyslog, wpanic, - longnames, allow_other, ro, reverse, aessiv, nonempty, raw64 bool + longnames, allow_other, ro, reverse, aessiv, nonempty, raw64, + noprealloc bool masterkey, mountpoint, cipherdir, cpuprofile, extpass, memprofile, ko, passfile, ctlsock string // Configuration file name override @@ -105,6 +106,7 @@ func parseCliOpts() (args argContainer) { flagSet.BoolVar(&args.aessiv, "aessiv", false, "AES-SIV encryption") flagSet.BoolVar(&args.nonempty, "nonempty", false, "Allow mounting over non-empty directories") flagSet.BoolVar(&args.raw64, "raw64", false, "Use unpadded base64 for file names") + flagSet.BoolVar(&args.noprealloc, "noprealloc", false, "Disable preallocation before writing") flagSet.StringVar(&args.masterkey, "masterkey", "", "Mount with explicit master key") flagSet.StringVar(&args.cpuprofile, "cpuprofile", "", "Write cpu profile to specified file") flagSet.StringVar(&args.memprofile, "memprofile", "", "Write memory profile to specified file") @@ -116,7 +118,7 @@ func parseCliOpts() (args argContainer) { flagSet.IntVar(&args.notifypid, "notifypid", 0, "Send USR1 to the specified process after "+ "successful mount - used internally for daemonization") flagSet.IntVar(&args.scryptn, "scryptn", configfile.ScryptDefaultLogN, "scrypt cost parameter logN. "+ - "Setting this to a lower value speeds up mounting but makes the password susceptible to brute-force attacks") + "A lower value speeds up mounting but makes the password susceptible to brute-force attacks") // Ignored otions var dummyBool bool ignoreText := "(ignored for compatibility)" diff --git a/internal/fusefrontend/args.go b/internal/fusefrontend/args.go index d8b0304..eb796cd 100644 --- a/internal/fusefrontend/args.go +++ b/internal/fusefrontend/args.go @@ -21,4 +21,6 @@ type Args struct { // Raw64 is true when RawURLEncoding (without padding) should be used for // file names Raw64 bool + // NoPrealloc disables automatic preallocation before writing + NoPrealloc bool } diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go index d637528..5fe866b 100644 --- a/internal/fusefrontend/file.go +++ b/internal/fusefrontend/file.go @@ -49,10 +49,12 @@ type file struct { // The opCount is used to judge whether "lastWrittenOffset" is still // guaranteed to be correct. lastOpCount uint64 + // Parent filesystem + fs *FS } // NewFile returns a new go-fuse File instance. -func NewFile(fd *os.File, writeOnly bool, contentEnc *contentenc.ContentEnc) (nodefs.File, fuse.Status) { +func NewFile(fd *os.File, writeOnly bool, fs *FS) (nodefs.File, fuse.Status) { var st syscall.Stat_t err := syscall.Fstat(int(fd.Fd()), &st) if err != nil { @@ -65,10 +67,11 @@ func NewFile(fd *os.File, writeOnly bool, contentEnc *contentenc.ContentEnc) (no return &file{ fd: fd, writeOnly: writeOnly, - contentEnc: contentEnc, + contentEnc: fs.contentEnc, devIno: di, fileTableEntry: t, loopbackFile: nodefs.NewLoopbackFile(fd), + fs: fs, }, fuse.OK } @@ -107,10 +110,12 @@ func (f *file) createHeader() (fileID []byte, err error) { h := contentenc.RandomHeader() buf := h.Pack() // Prevent partially written (=corrupt) header by preallocating the space beforehand - err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), 0, contentenc.HeaderLen) - if err != nil { - tlog.Warn.Printf("ino%d: createHeader: prealloc failed: %s\n", f.devIno.ino, err.Error()) - return nil, err + if !f.fs.args.NoPrealloc { + err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), 0, contentenc.HeaderLen) + if err != nil { + tlog.Warn.Printf("ino%d: createHeader: prealloc failed: %s\n", f.devIno.ino, err.Error()) + return nil, err + } } // Actually write header _, err = f.fd.WriteAt(buf, 0) @@ -285,7 +290,7 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) { writeChain[i] = blockData numOutBytes += len(blockData) } - // Concatenenate all elements in the writeChain into one contigous buffer + // Concatenenate all elements in the writeChain into one contiguous buffer tmp := make([]byte, numOutBytes) writeBuf := bytes.NewBuffer(tmp[:0]) for _, w := range writeChain { @@ -293,11 +298,14 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) { } // Preallocate so we cannot run out of space in the middle of the write. // This prevents partially written (=corrupt) blocks. + var err error cOff := blocks[0].BlockCipherOff() - err := syscallcompat.EnospcPrealloc(int(f.fd.Fd()), int64(cOff), int64(writeBuf.Len())) - if err != nil { - tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %s", f.devIno.ino, f.intFd(), err.Error()) - return 0, fuse.ToStatus(err) + if !f.fs.args.NoPrealloc { + err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), int64(cOff), int64(writeBuf.Len())) + if err != nil { + tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %s", f.devIno.ino, f.intFd(), err.Error()) + return 0, fuse.ToStatus(err) + } } // Write _, err = f.fd.WriteAt(writeBuf.Bytes(), int64(cOff)) diff --git a/internal/fusefrontend/fs.go b/internal/fusefrontend/fs.go index e9e6113..f41e9a7 100644 --- a/internal/fusefrontend/fs.go +++ b/internal/fusefrontend/fs.go @@ -106,7 +106,7 @@ func (fs *FS) Open(path string, flags uint32, context *fuse.Context) (fuseFile n return nil, fuse.ToStatus(err) } - return NewFile(f, writeOnly, fs.contentEnc) + return NewFile(f, writeOnly, fs) } // Create implements pathfs.Filesystem. @@ -160,7 +160,7 @@ func (fs *FS) Create(path string, flags uint32, mode uint32, context *fuse.Conte tlog.Warn.Printf("Create: Chown failed: %v", err) } } - return NewFile(fd, writeOnly, fs.contentEnc) + return NewFile(fd, writeOnly, fs) } // Chmod implements pathfs.Filesystem. @@ -145,6 +145,7 @@ func initFuseFrontend(key []byte, args *argContainer, confFile *configfile.ConfF CryptoBackend: cryptoBackend, ConfigCustom: args._configCustom, Raw64: args.raw64, + NoPrealloc: args.noprealloc, } // confFile is nil when "-zerokey" or "-masterkey" was used if confFile != nil { |