seaweedfs/weed/mount/weedfs_file_lseek.go

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package mount
import (
"syscall"
"github.com/hanwen/go-fuse/v2/fuse"
"github.com/seaweedfs/seaweedfs/weed/filer"
"github.com/seaweedfs/seaweedfs/weed/glog"
)
// These are non-POSIX extensions
const (
SEEK_DATA uint32 = 3 // seek to next data after the offset
SEEK_HOLE uint32 = 4 // seek to next hole after the offset
ENXIO = fuse.Status(syscall.ENXIO)
)
// Lseek finds next data or hole segments after the specified offset
// See https://man7.org/linux/man-pages/man2/lseek.2.html
func (wfs *WFS) Lseek(cancel <-chan struct{}, in *fuse.LseekIn, out *fuse.LseekOut) fuse.Status {
// not a documented feature
if in.Padding != 0 {
return fuse.EINVAL
}
if in.Whence != SEEK_DATA && in.Whence != SEEK_HOLE {
return fuse.EINVAL
}
// file must exist
fh := wfs.GetHandle(FileHandleId(in.Fh))
if fh == nil {
return fuse.EBADF
}
// lock the file until the proper offset was calculated
fh.RLock()
defer fh.RUnlock()
fh.entryLock.RLock()
defer fh.entryLock.RUnlock()
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fileSize := int64(filer.FileSize(fh.GetEntry()))
offset := max(int64(in.Offset), 0)
glog.V(4).Infof(
"Lseek %s fh %d in [%d,%d], whence %d",
fh.FullPath(), fh.fh, offset, fileSize, in.Whence,
)
// can neither seek beyond file nor seek to a hole at the end of the file with SEEK_DATA
if offset > fileSize {
return ENXIO
} else if in.Whence == SEEK_DATA && offset == fileSize {
return ENXIO
}
// search chunks for the offset
more solid weed mount (#4089) * compare chunks by timestamp * fix slab clearing error * fix test compilation * move oldest chunk to sealed, instead of by fullness * lock on fh.entryViewCache * remove verbose logs * revert slat clearing * less logs * less logs * track write and read by timestamp * remove useless logic * add entry lock on file handle release * use mem chunk only, swap file chunk has problems * comment out code that maybe used later * add debug mode to compare data read and write * more efficient readResolvedChunks with linked list * small optimization * fix test compilation * minor fix on writer * add SeparateGarbageChunks * group chunks into sections * turn off debug mode * fix tests * fix tests * tmp enable swap file chunk * Revert "tmp enable swap file chunk" This reverts commit 985137ec472924e4815f258189f6ca9f2168a0a7. * simple refactoring * simple refactoring * do not re-use swap file chunk. Sealed chunks should not be re-used. * comment out debugging facilities * either mem chunk or swap file chunk is fine now * remove orderedMutex as *semaphore.Weighted not found impactful * optimize size calculation for changing large files * optimize performance to avoid going through the long list of chunks * still problems with swap file chunk * rename * tiny optimization * swap file chunk save only successfully read data * fix * enable both mem and swap file chunk * resolve chunks with range * rename * fix chunk interval list * also change file handle chunk group when adding chunks * pick in-active chunk with time-decayed counter * fix compilation * avoid nil with empty fh.entry * refactoring * rename * rename * refactor visible intervals to *list.List * refactor chunkViews to *list.List * add IntervalList for generic interval list * change visible interval to use IntervalList in generics * cahnge chunkViews to *IntervalList[*ChunkView] * use NewFileChunkSection to create * rename variables * refactor * fix renaming leftover * renaming * renaming * add insert interval * interval list adds lock * incrementally add chunks to readers Fixes: 1. set start and stop offset for the value object 2. clone the value object 3. use pointer instead of copy-by-value when passing to interval.Value 4. use insert interval since adding chunk could be out of order * fix tests compilation * fix tests compilation
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found, offset := fh.entryChunkGroup.SearchChunks(offset, fileSize, in.Whence)
if found {
out.Offset = uint64(offset)
return fuse.OK
}
// in case we found no exact matches, we return the recommended fallbacks, that is:
// original offset for SEEK_DATA or end of file for an implicit hole
if in.Whence == SEEK_DATA {
out.Offset = in.Offset
} else {
out.Offset = uint64(fileSize)
}
return fuse.OK
}