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authorJakob Unterwurzacher2018-07-15 14:14:12 +0200
committerJakob Unterwurzacher2018-07-15 15:12:55 +0200
commitc70df522d2a78f3152fa61511bed9fafa7c495a3 (patch)
tree0ce081f2454a8e6da923355d11e5ed832ad7e302 /internal/fusefrontend/file.go
parent55bb22bad6c196f363ad27fbedad4f5360c4879f (diff)
fusefrontend: doWrite: delete file header if first write fails
xfstests generic/083 fills the filesystem almost completely while running fsstress in parallel. In fsck, these would show up: readFileID 2580: incomplete file, got 18 instead of 19 bytes This could happen when writing the file header works, but writing the actual data fails. Now we kill the header again by truncating the file to zero.
Diffstat (limited to 'internal/fusefrontend/file.go')
-rw-r--r--internal/fusefrontend/file.go94
1 files changed, 61 insertions, 33 deletions
diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go
index 1ae3386..ffc41c6 100644
--- a/internal/fusefrontend/file.go
+++ b/internal/fusefrontend/file.go
@@ -122,9 +122,9 @@ func (f *File) createHeader() (fileID []byte, err error) {
if !f.fs.args.NoPrealloc {
err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), 0, contentenc.HeaderLen)
if err != nil {
- // If the underlying filesystem is full, it is normal get ENOSPC here.
- // Log at Info level instead of Warning.
- tlog.Info.Printf("ino%d: createHeader: prealloc failed: %s\n", f.qIno.Ino, err.Error())
+ if !syscallcompat.IsENOSPC(err) {
+ tlog.Warn.Printf("ino%d: createHeader: prealloc failed: %s\n", f.qIno.Ino, err.Error())
+ }
return nil, err
}
}
@@ -144,33 +144,41 @@ func (f *File) createHeader() (fileID []byte, err error) {
// returns the requested part of the plaintext.
//
// Called by Read() for normal reading,
-// by Write() and Truncate() for Read-Modify-Write
-func (f *File) doRead(dst []byte, off uint64, length uint64) ([]byte, fuse.Status) {
- // Make sure we have the file ID.
- f.fileTableEntry.HeaderLock.RLock()
- if f.fileTableEntry.ID == nil {
- f.fileTableEntry.HeaderLock.RUnlock()
- // Yes, somebody else may take the lock before we can. This will get
- // the header read twice, but causes no harm otherwise.
- f.fileTableEntry.HeaderLock.Lock()
- tmpID, err := f.readFileID()
- if err == io.EOF {
- f.fileTableEntry.HeaderLock.Unlock()
- return nil, fuse.OK
- }
- if err != nil {
+// by Write() and Truncate() via doWrite() for Read-Modify-Write.
+//
+// doWrite() uses nolock=true because it makes sure the ID is in the cache and
+// HeaderLock is locked before calling doRead.
+func (f *File) doRead(dst []byte, off uint64, length uint64, nolock bool) ([]byte, fuse.Status) {
+ if !nolock {
+ // Make sure we have the file ID.
+ f.fileTableEntry.HeaderLock.RLock()
+ if f.fileTableEntry.ID == nil {
+ f.fileTableEntry.HeaderLock.RUnlock()
+ // Yes, somebody else may take the lock before we can. This will get
+ // the header read twice, but causes no harm otherwise.
+ f.fileTableEntry.HeaderLock.Lock()
+ tmpID, err := f.readFileID()
+ if err == io.EOF {
+ f.fileTableEntry.HeaderLock.Unlock()
+ return nil, fuse.OK
+ }
+ if err != nil {
+ f.fileTableEntry.HeaderLock.Unlock()
+ tlog.Warn.Printf("doRead %d: corrupt header: %v", f.qIno.Ino, err)
+ return nil, fuse.EIO
+ }
+ f.fileTableEntry.ID = tmpID
+ // Downgrade the lock.
f.fileTableEntry.HeaderLock.Unlock()
- tlog.Warn.Printf("doRead %d: corrupt header: %v", f.qIno.Ino, err)
- return nil, fuse.EIO
+ // The file ID may change in here. This does no harm because we
+ // re-read it after the RLock().
+ f.fileTableEntry.HeaderLock.RLock()
}
- f.fileTableEntry.ID = tmpID
- // Downgrade the lock.
- f.fileTableEntry.HeaderLock.Unlock()
- // The file ID may change in here. This does no harm because we
- // re-read it after the RLock().
- f.fileTableEntry.HeaderLock.RLock()
}
fileID := f.fileTableEntry.ID
+ if fileID == nil {
+ log.Panicf("filedID=%v, nolock=%v", fileID, nolock)
+ }
// Read the backing ciphertext in one go
blocks := f.contentEnc.ExplodePlainRange(off, length)
alignedOffset, alignedLength := blocks[0].JointCiphertextRange(blocks)
@@ -182,7 +190,9 @@ func (f *File) doRead(dst []byte, off uint64, length uint64) ([]byte, fuse.Statu
ciphertext = ciphertext[: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.
- f.fileTableEntry.HeaderLock.RUnlock()
+ if !nolock {
+ f.fileTableEntry.HeaderLock.RUnlock()
+ }
if err != nil && err != io.EOF {
tlog.Warn.Printf("read: ReadAt: %s", err.Error())
return nil, fuse.ToStatus(err)
@@ -245,7 +255,7 @@ func (f *File) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus
if f.fs.args.SerializeReads {
serialize_reads.Wait(off, len(buf))
}
- out, status := f.doRead(buf[:0], uint64(off), uint64(len(buf)))
+ out, status := f.doRead(buf[:0], uint64(off), uint64(len(buf)), false)
if f.fs.args.SerializeReads {
serialize_reads.Done()
}
@@ -266,6 +276,7 @@ func (f *File) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus
//
// Empty writes do nothing and are allowed.
func (f *File) doWrite(data []byte, off int64) (uint32, fuse.Status) {
+ fileWasEmpty := false
// If the file ID is not cached, read it from disk
if f.fileTableEntry.ID == nil {
// Block other readers while we mess with the file header. Other writers
@@ -275,13 +286,22 @@ func (f *File) doWrite(data []byte, off int64) (uint32, fuse.Status) {
// Write a new file header if the file is empty
if err == io.EOF {
tmpID, err = f.createHeader()
+ fileWasEmpty = true
}
if err != nil {
f.fileTableEntry.HeaderLock.Unlock()
return 0, fuse.ToStatus(err)
}
f.fileTableEntry.ID = tmpID
- f.fileTableEntry.HeaderLock.Unlock()
+ if fileWasEmpty {
+ // The file was empty and we wrote a new file header. Keep the lock
+ // as we might have to kill the file header again if the data write
+ // fails.
+ defer f.fileTableEntry.HeaderLock.Unlock()
+ } else {
+ // We won't touch the header again, drop the lock immediately.
+ f.fileTableEntry.HeaderLock.Unlock()
+ }
}
// Handle payload data
dataBuf := bytes.NewBuffer(data)
@@ -292,7 +312,7 @@ func (f *File) doWrite(data []byte, off int64) (uint32, fuse.Status) {
// Incomplete block -> Read-Modify-Write
if b.IsPartial() {
// Read
- oldData, status := f.doRead(nil, b.BlockPlainOff(), f.contentEnc.PlainBS())
+ oldData, status := f.doRead(nil, b.BlockPlainOff(), f.contentEnc.PlainBS(), true)
if status != fuse.OK {
tlog.Warn.Printf("ino%d fh%d: RMW read failed: %s", f.qIno.Ino, f.intFd(), status.String())
return 0, status
@@ -315,9 +335,17 @@ func (f *File) doWrite(data []byte, off int64) (uint32, fuse.Status) {
if !f.fs.args.NoPrealloc {
err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), cOff, int64(len(ciphertext)))
if err != nil {
- // If the underlying filesystem is full, it is normal get ENOSPC here.
- // Log at Info level instead of Warning.
- tlog.Info.Printf("ino%d fh%d: doWrite: prealloc failed: %s", f.qIno.Ino, f.intFd(), err.Error())
+ if !syscallcompat.IsENOSPC(err) {
+ tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %v", f.qIno.Ino, f.intFd(), err)
+ }
+ if fileWasEmpty {
+ // Kill the file header again
+ f.fileTableEntry.ID = nil
+ err2 := syscall.Ftruncate(int(f.fd.Fd()), 0)
+ if err2 != nil {
+ tlog.Warn.Printf("ino%d fh%d: doWrite: rollback failed: %v", f.qIno.Ino, f.intFd(), err2)
+ }
+ }
return 0, fuse.ToStatus(err)
}
}