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2019-11-25Minor VFS2 interface changes.Jamie Liu
- 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
2019-11-25Implement basic umounting for vfs2.Jamie Liu
This is required to test filesystems with a non-trivial implementation of FilesystemImpl.Release(). Propagation isn't handled yet, and umount isn't yet plumbed out to VirtualFilesystem.UmountAt(), but otherwise the implementation of umount is believed to be correct. - Move entering mountTable.seq writer critical sections to callers of mountTable.{insert,remove}Seqed. This is required since umount(2) must ensure that no new references are taken on the candidate mount after checking that it isn't busy, which is only possible by entering a vfs.mountTable.seq writer critical section before the check and remaining in it until after VFS.umountRecursiveLocked() is complete. (Linux does the same thing: fs/namespace.c:do_umount() => lock_mount_hash(), fs/pnode.c:propagate_mount_busy(), umount_tree(), unlock_mount_hash().) - It's not possible for dentry deletion to umount while only holding VFS.mountMu for reading, but it's also very unappealing to hold VFS.mountMu exclusively around e.g. gofer unlink RPCs. Introduce dentry.mu to avoid these problems. This means that VFS.mountMu is never acquired for reading, so change it to a sync.Mutex. PiperOrigin-RevId: 282444343
2019-11-21Import and structure cleanup.Adin Scannell
PiperOrigin-RevId: 281795269
2019-10-19Add support for pipes in VFS2.Kevin Krakauer
PiperOrigin-RevId: 275650307
2019-10-16Reorder BUILD license and load functions in gvisor.Kevin Krakauer
PiperOrigin-RevId: 275139066
2019-10-15Minor vfs.FileDescriptionImpl fixes.Jamie Liu
- Pass context.Context to OnClose(). - Pass memmap.MMapOpts to ConfigureMMap() by pointer so that implementations can actually mutate it as required. PiperOrigin-RevId: 274934967
2019-10-04Change linux.FileMode from uint to uint16, and update VFS to use FileMode.Kevin Krakauer
In Linux (include/linux/types.h), mode_t is an unsigned short. PiperOrigin-RevId: 272956350
2019-09-20Change vfs.Dirent.Off to NextOff.Jamie Liu
"d_off is the distance from the start of the directory to the start of the next linux_dirent." - getdents(2). PiperOrigin-RevId: 270349685
2019-09-12Remove go_test from go_stateify and go_marshalMichael Pratt
They are no-ops, so the standard rule works fine. PiperOrigin-RevId: 268776264
2019-09-03Impose order on test scripts.Adin Scannell
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
2019-08-16procfs: Migrate seqfile implementations.Ayush Ranjan
Migrates all (except 3) seqfile implementations to the vfs.DynamicBytesSource interface. There should not be any change in functionality due to this migration itself. Please note that the following seqfile implementations have not been migrated: - /proc/filesystems in proc/filesystems.go - /proc/[pid]/mountinfo in proc/mounts.go - /proc/[pid]/mounts in proc/mounts.go This is because these depend on pending changes in /pkg/senty/vfs. PiperOrigin-RevId: 263880719
2019-08-16vfs: Remove vfs.DefaultDirectoryFD from embedding vfs.DefaultFD.Ayush Ranjan
This fixes the implementation ambiguity issues when a filesystem implementation embeds vfs.DefaultDirectoryFD to its directory FD along with an internal common fileDescription utility. For similar reasons also removes FileDescriptionDefaultImpl from DynamicBytesFileDescriptionImpl. PiperOrigin-RevId: 263795513
2019-08-09ext: Move to pkg/sentry/fsimpl.Ayush Ranjan
fsimpl is the keeper of all filesystem implementations in VFS2. PiperOrigin-RevId: 262617869
2019-08-08memfs fixes.Jamie Liu
- Unexport Filesystem/Dentry/Inode. - Support SEEK_CUR in directoryFD.Seek(). - Hold Filesystem.mu before touching directoryFD.off in directoryFD.Seek(). - Remove deleted Dentries from their parent directory.childLists. - Remove invalid FIXMEs. PiperOrigin-RevId: 262400633
2019-07-18Sentry virtual filesystem, v2Jamie Liu
Major differences from the current ("v1") sentry VFS: - Path resolution is Filesystem-driven (FilesystemImpl methods call vfs.ResolvingPath methods) rather than VFS-driven (fs package owns a Dirent tree and calls fs.InodeOperations methods to populate it). This drastically improves performance, primarily by reducing overhead from inefficient synchronization and indirection. It also makes it possible to implement remote filesystem protocols that translate FS system calls into single RPCs, rather than having to make (at least) one RPC per path component, significantly reducing the latency of remote filesystems (especially during cold starts and for uncacheable shared filesystems). - Mounts are correctly represented as a separate check based on contextual state (current mount) rather than direct replacement in a fs.Dirent tree. This makes it possible to support (non-recursive) bind mounts and mount namespaces. Included in this CL is fsimpl/memfs, an incomplete in-memory filesystem that exists primarily to demonstrate intended filesystem implementation patterns and for benchmarking: BenchmarkVFS1TmpfsStat/1-6 3000000 497 ns/op BenchmarkVFS1TmpfsStat/2-6 2000000 676 ns/op BenchmarkVFS1TmpfsStat/3-6 2000000 904 ns/op BenchmarkVFS1TmpfsStat/8-6 1000000 1944 ns/op BenchmarkVFS1TmpfsStat/64-6 100000 14067 ns/op BenchmarkVFS1TmpfsStat/100-6 50000 21700 ns/op BenchmarkVFS2MemfsStat/1-6 10000000 197 ns/op BenchmarkVFS2MemfsStat/2-6 5000000 233 ns/op BenchmarkVFS2MemfsStat/3-6 5000000 268 ns/op BenchmarkVFS2MemfsStat/8-6 3000000 477 ns/op BenchmarkVFS2MemfsStat/64-6 500000 2592 ns/op BenchmarkVFS2MemfsStat/100-6 300000 4045 ns/op BenchmarkVFS1TmpfsMountStat/1-6 2000000 679 ns/op BenchmarkVFS1TmpfsMountStat/2-6 2000000 912 ns/op BenchmarkVFS1TmpfsMountStat/3-6 1000000 1113 ns/op BenchmarkVFS1TmpfsMountStat/8-6 1000000 2118 ns/op BenchmarkVFS1TmpfsMountStat/64-6 100000 14251 ns/op BenchmarkVFS1TmpfsMountStat/100-6 100000 22397 ns/op BenchmarkVFS2MemfsMountStat/1-6 5000000 317 ns/op BenchmarkVFS2MemfsMountStat/2-6 5000000 361 ns/op BenchmarkVFS2MemfsMountStat/3-6 5000000 387 ns/op BenchmarkVFS2MemfsMountStat/8-6 3000000 582 ns/op BenchmarkVFS2MemfsMountStat/64-6 500000 2699 ns/op BenchmarkVFS2MemfsMountStat/100-6 300000 4133 ns/op From this we can infer that, on this machine: - Constant cost for tmpfs stat() is ~160ns in VFS2 and ~280ns in VFS1. - Per-path-component cost is ~35ns in VFS2 and ~215ns in VFS1, a difference of about 6x. - The cost of crossing a mount boundary is about 80ns in VFS2 (MemfsMountStat/1 does approximately the same amount of work as MemfsStat/2, except that it also crosses a mount boundary). This is an inescapable cost of the separate mount lookup needed to support bind mounts and mount namespaces. PiperOrigin-RevId: 258853946