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-rw-r--r--pkg/sentry/fs/fsutil/host_mappable.go2
-rw-r--r--pkg/sentry/fs/fsutil/inode_cached.go22
-rw-r--r--pkg/sentry/fs/gofer/inode.go15
-rw-r--r--pkg/sentry/fs/host/inode.go4
4 files changed, 28 insertions, 15 deletions
diff --git a/pkg/sentry/fs/fsutil/host_mappable.go b/pkg/sentry/fs/fsutil/host_mappable.go
index d2495cb83..693625ddc 100644
--- a/pkg/sentry/fs/fsutil/host_mappable.go
+++ b/pkg/sentry/fs/fsutil/host_mappable.go
@@ -144,7 +144,7 @@ func (h *HostMappable) Truncate(ctx context.Context, newSize int64) error {
mask := fs.AttrMask{Size: true}
attr := fs.UnstableAttr{Size: newSize}
- if err := h.backingFile.SetMaskedAttributes(ctx, mask, attr); err != nil {
+ if err := h.backingFile.SetMaskedAttributes(ctx, mask, attr, false); err != nil {
return err
}
diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go
index d404a79d4..dd80757dc 100644
--- a/pkg/sentry/fs/fsutil/inode_cached.go
+++ b/pkg/sentry/fs/fsutil/inode_cached.go
@@ -140,12 +140,16 @@ type CachedFileObject interface {
// WriteFromBlocksAt may return a partial write without an error.
WriteFromBlocksAt(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)
- // SetMaskedAttributes sets the attributes in attr that are true in mask
- // on the backing file.
+ // SetMaskedAttributes sets the attributes in attr that are true in
+ // mask on the backing file. If the mask contains only ATime or MTime
+ // and the CachedFileObject has an FD to the file, then this operation
+ // is a noop unless forceSetTimestamps is true. This avoids an extra
+ // RPC to the gofer in the open-read/write-close case, when the
+ // timestamps on the file will be updated by the host kernel for us.
//
// SetMaskedAttributes may be called at any point, regardless of whether
// the file was opened.
- SetMaskedAttributes(ctx context.Context, mask fs.AttrMask, attr fs.UnstableAttr) error
+ SetMaskedAttributes(ctx context.Context, mask fs.AttrMask, attr fs.UnstableAttr, forceSetTimestamps bool) error
// Allocate allows the caller to reserve disk space for the inode.
// It's equivalent to fallocate(2) with 'mode=0'.
@@ -224,7 +228,7 @@ func (c *CachingInodeOperations) SetPermissions(ctx context.Context, inode *fs.I
now := ktime.NowFromContext(ctx)
masked := fs.AttrMask{Perms: true}
- if err := c.backingFile.SetMaskedAttributes(ctx, masked, fs.UnstableAttr{Perms: perms}); err != nil {
+ if err := c.backingFile.SetMaskedAttributes(ctx, masked, fs.UnstableAttr{Perms: perms}, false); err != nil {
return false
}
c.attr.Perms = perms
@@ -246,7 +250,7 @@ func (c *CachingInodeOperations) SetOwner(ctx context.Context, inode *fs.Inode,
UID: owner.UID.Ok(),
GID: owner.GID.Ok(),
}
- if err := c.backingFile.SetMaskedAttributes(ctx, masked, fs.UnstableAttr{Owner: owner}); err != nil {
+ if err := c.backingFile.SetMaskedAttributes(ctx, masked, fs.UnstableAttr{Owner: owner}, false); err != nil {
return err
}
if owner.UID.Ok() {
@@ -282,7 +286,9 @@ func (c *CachingInodeOperations) SetTimestamps(ctx context.Context, inode *fs.In
AccessTime: !ts.ATimeOmit,
ModificationTime: !ts.MTimeOmit,
}
- if err := c.backingFile.SetMaskedAttributes(ctx, masked, fs.UnstableAttr{AccessTime: ts.ATime, ModificationTime: ts.MTime}); err != nil {
+ // Call SetMaskedAttributes with forceSetTimestamps = true to make sure
+ // the timestamp is updated.
+ if err := c.backingFile.SetMaskedAttributes(ctx, masked, fs.UnstableAttr{AccessTime: ts.ATime, ModificationTime: ts.MTime}, true); err != nil {
return err
}
if !ts.ATimeOmit {
@@ -305,7 +311,7 @@ func (c *CachingInodeOperations) Truncate(ctx context.Context, inode *fs.Inode,
now := ktime.NowFromContext(ctx)
masked := fs.AttrMask{Size: true}
attr := fs.UnstableAttr{Size: size}
- if err := c.backingFile.SetMaskedAttributes(ctx, masked, attr); err != nil {
+ if err := c.backingFile.SetMaskedAttributes(ctx, masked, attr, false); err != nil {
c.dataMu.Unlock()
return err
}
@@ -394,7 +400,7 @@ func (c *CachingInodeOperations) WriteOut(ctx context.Context, inode *fs.Inode)
c.dirtyAttr.Size = false
// Write out cached attributes.
- if err := c.backingFile.SetMaskedAttributes(ctx, c.dirtyAttr, c.attr); err != nil {
+ if err := c.backingFile.SetMaskedAttributes(ctx, c.dirtyAttr, c.attr, false); err != nil {
c.attrMu.Unlock()
return err
}
diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go
index 95b064aea..d918d6620 100644
--- a/pkg/sentry/fs/gofer/inode.go
+++ b/pkg/sentry/fs/gofer/inode.go
@@ -215,8 +215,8 @@ func (i *inodeFileState) WriteFromBlocksAt(ctx context.Context, srcs safemem.Blo
}
// SetMaskedAttributes implements fsutil.CachedFileObject.SetMaskedAttributes.
-func (i *inodeFileState) SetMaskedAttributes(ctx context.Context, mask fs.AttrMask, attr fs.UnstableAttr) error {
- if i.skipSetAttr(mask) {
+func (i *inodeFileState) SetMaskedAttributes(ctx context.Context, mask fs.AttrMask, attr fs.UnstableAttr, forceSetTimestamps bool) error {
+ if i.skipSetAttr(mask, forceSetTimestamps) {
return nil
}
as, ans := attr.AccessTime.Unix()
@@ -251,13 +251,14 @@ func (i *inodeFileState) SetMaskedAttributes(ctx context.Context, mask fs.AttrMa
// when:
// - Mask is empty
// - Mask contains only attributes that cannot be set in the gofer
-// - Mask contains only atime and/or mtime, and host FD exists
+// - forceSetTimestamps is false and mask contains only atime and/or mtime
+// and host FD exists
//
// Updates to atime and mtime can be skipped because cached value will be
// "close enough" to host value, given that operation went directly to host FD.
// Skipping atime updates is particularly important to reduce the number of
// operations sent to the Gofer for readonly files.
-func (i *inodeFileState) skipSetAttr(mask fs.AttrMask) bool {
+func (i *inodeFileState) skipSetAttr(mask fs.AttrMask, forceSetTimestamps bool) bool {
// First remove attributes that cannot be updated.
cpy := mask
cpy.Type = false
@@ -277,6 +278,12 @@ func (i *inodeFileState) skipSetAttr(mask fs.AttrMask) bool {
return false
}
+ // If forceSetTimestamps was passed, then we cannot skip.
+ if forceSetTimestamps {
+ return false
+ }
+
+ // Skip if we have a host FD.
i.handlesMu.RLock()
defer i.handlesMu.RUnlock()
return (i.readHandles != nil && i.readHandles.Host != nil) ||
diff --git a/pkg/sentry/fs/host/inode.go b/pkg/sentry/fs/host/inode.go
index 894ab01f0..a6e4a09e3 100644
--- a/pkg/sentry/fs/host/inode.go
+++ b/pkg/sentry/fs/host/inode.go
@@ -114,7 +114,7 @@ func (i *inodeFileState) WriteFromBlocksAt(ctx context.Context, srcs safemem.Blo
}
// SetMaskedAttributes implements fsutil.CachedFileObject.SetMaskedAttributes.
-func (i *inodeFileState) SetMaskedAttributes(ctx context.Context, mask fs.AttrMask, attr fs.UnstableAttr) error {
+func (i *inodeFileState) SetMaskedAttributes(ctx context.Context, mask fs.AttrMask, attr fs.UnstableAttr, _ bool) error {
if mask.Empty() {
return nil
}
@@ -163,7 +163,7 @@ func (i *inodeFileState) unstableAttr(ctx context.Context) (fs.UnstableAttr, err
return unstableAttr(i.mops, &s), nil
}
-// SetMaskedAttributes implements fsutil.CachedFileObject.SetMaskedAttributes.
+// Allocate implements fsutil.CachedFileObject.Allocate.
func (i *inodeFileState) Allocate(_ context.Context, offset, length int64) error {
return syscall.Fallocate(i.FD(), 0, offset, length)
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 07:43:27 +0000