- Add type parameter Filesystem to vfs/genericfstree, which is required to
provide `ancestryMu sync.RWMutex`, and add such a RWMutex to all FSImpls that
use genericfstree.
- Modify genericfstree.PrependPath() and genericfstree.IsDescendant() to use
ancestryMu to ensure atomicity. For callers of genericfstree.PrependPath(),
this means that (broader) FSImpl locks no longer need to be held during the
call. For callers of genericfstree.IsDescendant(), this means that we can
remove documentation warnings about its non-atomicity.
- Minor cleanup: Remove useless variable `start`, which is always 0, from
MM.ReadMaps/SmapsDataInto().
PiperOrigin-RevId: 696713993
IsDescendant gives the VFS layer an easy way to check if a dentry is a
descendant of another, which is important for some mounting procedures.
This method does not take any locks when accessing the parent, so parent
fields need to switch to be atomic to avoid data races.
PiperOrigin-RevId: 570454446
Inode number consistency checks are now skipped in save/restore tests for
reasons described in greatest detail in StatTest.StateDoesntChangeAfterRename.
They pass in VFS1 due to the bug described in new test case
SimpleStatTest.DifferentFilesHaveDifferentDeviceInodeNumberPairs.
Fixes#1663
PiperOrigin-RevId: 338776148
This is mostly syscall plumbing, VFS2 already implements the internals of
mounts. In addition to the syscall defintions, the following mount-related
mechanisms are updated:
- Implement MS_NOATIME for VFS2, but only for tmpfs and goferfs. The other VFS2
filesystems don't implement node-level timestamps yet.
- Implement the 'mode', 'uid' and 'gid' mount options for VFS2's tmpfs.
- Plumb mount namespace ownership, which is necessary for checking appropriate
capabilities during mount(2).
Updates #1035
PiperOrigin-RevId: 315035352
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