diff options
Diffstat (limited to 'pkg/sentry')
| -rw-r--r-- | pkg/sentry/fs/g3doc/fuse.md | 9 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/tmpfs/filesystem.go | 4 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/tmpfs/tmpfs.go | 15 |
3 files changed, 16 insertions, 12 deletions
diff --git a/pkg/sentry/fs/g3doc/fuse.md b/pkg/sentry/fs/g3doc/fuse.md index cc08c14f5..b43c082a7 100644 --- a/pkg/sentry/fs/g3doc/fuse.md +++ b/pkg/sentry/fs/g3doc/fuse.md @@ -255,7 +255,8 @@ I/O syscalls like `read(2)`, `write(2)` and `mmap(2)`. # References -- [fuse(4) Linux manual page](https://www.man7.org/linux/man-pages/man4/fuse.4.html) -- [Linux kernel FUSE documentation](https://www.kernel.org/doc/html/latest/filesystems/fuse.html) -- [The reference implementation of the Linux FUSE (Filesystem in Userspace) interface](https://github.com/libfuse/libfuse) -- [The kernel interface of FUSE](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/fuse.h) +- [fuse(4) Linux manual page](https://www.man7.org/linux/man-pages/man4/fuse.4.html) +- [Linux kernel FUSE documentation](https://www.kernel.org/doc/html/latest/filesystems/fuse.html) +- [The reference implementation of the Linux FUSE (Filesystem in Userspace) + interface](https://github.com/libfuse/libfuse) +- [The kernel interface of FUSE](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/fuse.h) diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go index 80fa7b29d..7c04570f1 100644 --- a/pkg/sentry/fsimpl/tmpfs/filesystem.go +++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go @@ -603,8 +603,10 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error return err } parentDir.removeChildLocked(child) - parentDir.inode.decLinksLocked() // from child's ".." + // Remove links for child, child/., and child/.. child.inode.decLinksLocked() + child.inode.decLinksLocked() + parentDir.inode.decLinksLocked() vfsObj.CommitDeleteDentry(&child.vfsd) parentDir.inode.touchCMtime() return nil diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go index 1e781aecd..b739095b7 100644 --- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go +++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go @@ -209,11 +209,9 @@ type inode struct { // refs is a reference count. refs is accessed using atomic memory // operations. // - // A reference is held on all inodes that are reachable in the filesystem - // tree. For non-directories (which may have multiple hard links), this - // means that a reference is dropped when nlink reaches 0. For directories, - // nlink never reaches 0 due to the "." entry; instead, - // filesystem.RmdirAt() drops the reference. + // A reference is held on all inodes as long as they are reachable in the + // filesystem tree, i.e. nlink is nonzero. This reference is dropped when + // nlink reaches 0. refs int64 // xattrs implements extended attributes. @@ -276,14 +274,17 @@ func (i *inode) incLinksLocked() { atomic.AddUint32(&i.nlink, 1) } -// decLinksLocked decrements i's link count. +// decLinksLocked decrements i's link count. If the link count reaches 0, we +// remove a reference on i as well. // // Preconditions: filesystem.mu must be locked for writing. i.nlink != 0. func (i *inode) decLinksLocked() { if i.nlink == 0 { panic("tmpfs.inode.decLinksLocked() called with no existing links") } - atomic.AddUint32(&i.nlink, ^uint32(0)) + if atomic.AddUint32(&i.nlink, ^uint32(0)) == 0 { + i.decRef() + } } func (i *inode) incRef() { |