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Clean up logic for when a VFS2 gofer regular file close causes a flushf.

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PiperOrigin-RevId: 386577891
This commit is contained in:
Jamie Liu
2021-07-23 19:53:54 -07:00
committed by gVisor bot
parent d247938363
commit 9ba8c40a3a
1 changed files with 19 additions and 20 deletions
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pkg/sentry/fsimpl/gofer/regular_file.go
+19 -20
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@@ -79,17 +79,22 @@ func (fd *regularFileFD) OnClose(ctx context.Context) error {
if !fd.vfsfd.IsWritable() {
return nil
}
// Skip flushing if there are client-buffered writes, since (as with the
// VFS1 client) we don't flush buffered writes on close anyway.
d := fd.dentry()
if d.fs.opts.interop != InteropModeExclusive {
return nil
}
d.dataMu.RLock()
haveDirtyPages := !d.dirty.IsEmpty()
d.dataMu.RUnlock()
if haveDirtyPages {
return nil
if d.fs.opts.interop == InteropModeExclusive {
// d may have dirty pages that we won't write back now (and wouldn't
// have in VFS1), making a flushf RPC ineffective. If this is the case,
// skip the flushf.
//
// Note that it's also possible to have dirty pages under other interop
// modes if forcePageCache is in effect; we conservatively assume that
// applications have some way of tolerating this and still want the
// flushf.
d.dataMu.RLock()
haveDirtyPages := !d.dirty.IsEmpty()
d.dataMu.RUnlock()
if haveDirtyPages {
return nil
}
}
d.handleMu.RLock()
defer d.handleMu.RUnlock()
@@ -707,14 +712,8 @@ func (fd *regularFileFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpt
return vfs.GenericConfigureMMap(&fd.vfsfd, d, opts)
}
func (d *dentry) mayCachePages() bool {
if d.fs.opts.forcePageCache {
return true
}
if d.fs.opts.interop == InteropModeShared {
return false
}
return atomic.LoadInt32(&d.mmapFD) >= 0
func (fs *filesystem) mayCachePagesInMemoryFile() bool {
return fs.opts.forcePageCache || fs.opts.interop != InteropModeShared
}
// AddMapping implements memmap.Mappable.AddMapping.
@@ -726,7 +725,7 @@ func (d *dentry) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar host
for _, r := range mapped {
d.pf.hostFileMapper.IncRefOn(r)
}
if d.mayCachePages() {
if d.fs.mayCachePagesInMemoryFile() {
// d.Evict() will refuse to evict memory-mapped pages, so tell the
// MemoryFile to not bother trying.
mf := d.fs.mfp.MemoryFile()
@@ -745,7 +744,7 @@ func (d *dentry) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar h
for _, r := range unmapped {
d.pf.hostFileMapper.DecRefOn(r)
}
if d.mayCachePages() {
if d.fs.mayCachePagesInMemoryFile() {
// Pages that are no longer referenced by any application memory
// mappings are now considered unused; allow MemoryFile to evict them
// when necessary.