Commit Graph

7 Commits

Author SHA1 Message Date
Jamie Liu 796f53c0be Add VFS2 support for /proc/filesystems.
Updates #1195

PiperOrigin-RevId: 287269106
2019-12-27 00:13:54 -08:00
Jamie Liu f45df7505b Clean up vfs.FilesystemImpl methods that operate on parent directories.
- Make FilesystemImpl methods that operate on parent directories require
  !rp.Done() (i.e. there is at least one path component to resolve) as
  precondition and postcondition (in cases where they do not finish path
  resolution due to mount boundary / absolute symlink), and require that they
  do not need to follow the last path component (the file being created /
  deleted) as a symlink. Check for these in VFS.

- Add FilesystemImpl.GetParentDentryAt(), which is required to obtain the old
  parent directory for VFS.RenameAt(). (Passing the Dentry to be renamed
  instead has the wrong semantics if the file named by the old path is a mount
  point since the Dentry will be on the wrong Mount.)

- Update memfs to implement these methods correctly (?), including RenameAt.

- Change fspath.Parse() to allow empty paths (to simplify implementation of
  AT_EMPTY_PATH).

- Change vfs.PathOperation to take a fspath.Path instead of a raw pathname;
  non-test callers will need to fspath.Parse() pathnames themselves anyway in
  order to detect absolute paths and select PathOperation.Start accordingly.

PiperOrigin-RevId: 286934941
2019-12-23 13:18:39 -08:00
Jamie Liu 46651a7d26 Add most VFS methods for syscalls.
PiperOrigin-RevId: 284892289
2019-12-10 18:21:07 -08:00
Jamie Liu b72e1b3c08 Minor VFS2 interface changes.
- Remove the Filesystem argument from DentryImpl.*Ref(); in general DentryImpls
  that need the Filesystem for reference counting will probably also need it
  for other interface methods that don't plumb Filesystem, so it's easier to
  just store a pointer to the filesystem in the DentryImpl.

- Add a pointer to the VirtualFilesystem to Filesystem, which is needed by the
  gofer client to disown dentries for cache eviction triggered by dentry
  reference count changes.

- Rename FilesystemType.NewFilesystem to GetFilesystem; in some cases (e.g.
  sysfs, cgroupfs) it's much cleaner for there to be only one Filesystem that
  is used by all mounts, and in at least one case (devtmpfs) it's visibly
  incorrect not to do so, so NewFilesystem doesn't always actually create and
  return a *new* Filesystem.

- Require callers of FileDescription.Init() to increment Mount/Dentry
  references. This is because the gofer client may, in the OpenAt() path, take
  a reference on a dentry with 0 references, which is safe due to
  synchronization that is outside the scope of this CL, and it would be safer
  to still have its implementation of DentryImpl.IncRef() check for an
  increment for 0 references in other cases.

- Add FileDescription.TryIncRef. This is used by the gofer client to take
  references on "special file descriptions" (FDs for files such as pipes,
  sockets, and devices), which use per-FD handles (fids) instead of
  dentry-shared handles, for sync() and syncfs().

PiperOrigin-RevId: 282473364
2019-11-25 18:10:31 -08:00
Jamie Liu fb55c2bd0d Change vfs.Dirent.Off to NextOff.
"d_off is the distance from the start of the directory to the start of the next
linux_dirent." - getdents(2).

PiperOrigin-RevId: 270349685
2019-09-20 14:24:29 -07:00
Adin Scannell 67a2ab1438 Impose order on test scripts.
The simple test script has gotten out of control. Shard this script into
different pieces and attempt to impose order on overall test structure. This
change helps lay some of the foundations for future improvements.

 * The runsc/test directories are moved into just test/.
 * The runsc/test/testutil package is split into logical pieces.
 * The scripts/ directory contains new top-level targets.
 * Each test is now responsible for building targets it requires.
 * The install functionality is moved into `runsc` itself for simplicity.
 * The existing kokoro run_tests.sh file now just calls all (can be split).

After this change is merged,  I will create multiple distinct workflows for
Kokoro, one for each of the scripts currently targeted by `run_tests.sh` today,
which should dramatically reduce the time-to-run for the Kokoro tests, and
provides a better foundation for further improvements to the infrastructure.

PiperOrigin-RevId: 267081397
2019-09-03 22:02:43 -07:00
Ayush Ranjan c8961a6cbd ext: Move to pkg/sentry/fsimpl.
fsimpl is the keeper of all filesystem implementations in VFS2.

PiperOrigin-RevId: 262617869
2019-08-09 13:08:28 -07:00