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2020-02-14Allow vfs.IterDirentsCallback.Handle() to return an error.gVisor bot
This is easier than storing errors from e.g. CopyOut in the callback. PiperOrigin-RevId: 295230021
2020-02-14Inline vfs.VirtualFilesystem in Kernel structgVisor bot
This saves one pointer dereference per VFS access. Updates #1623 PiperOrigin-RevId: 295216176
2020-02-14Plumb VFS2 inside the SentrygVisor bot
- Added fsbridge package with interface that can be used to open and read from VFS1 and VFS2 files. - Converted ELF loader to use fsbridge - Added VFS2 types to FSContext - Added vfs.MountNamespace to ThreadGroup Updates #1623 PiperOrigin-RevId: 295183950
2020-02-13Add FileExec flag to OpenOptionsgVisor bot
This allow callers to say whether the file is being opened to be executed, so that the proper checks can be done from FilesystemImpl.OpenAt() Updates #1623 PiperOrigin-RevId: 295042595
2020-02-11Ensure fsimpl/gofer.dentryPlatformFile.hostFileMapper is initialized.gVisor bot
Fixes #1812. (The more direct cause of the deadlock is panic unsafety because the historically high cost of defer means that we avoid it in hot paths, including much of MM; defer is much cheaper as of Go 1.14, but still a measurable overhead.) PiperOrigin-RevId: 294560316
2020-02-10Add contextual comment.Adin Scannell
PiperOrigin-RevId: 294289066
2020-02-10Add contextual note.Adin Scannell
PiperOrigin-RevId: 294285723
2020-02-10Redirect FIXME to gvisor.devFabricio Voznika
PiperOrigin-RevId: 294272755
2020-02-04Remove argument from vfs.MountNamespace.DecRef()Fabricio Voznika
Updates #1035 PiperOrigin-RevId: 293194631
2020-02-04VFS2 gofer clientJamie Liu
Updates #1198 Opening host pipes (by spinning in fdpipe) and host sockets is not yet complete, and will be done in a future CL. Major differences from VFS1 gofer client (sentry/fs/gofer), with varying levels of backportability: - "Cache policies" are replaced by InteropMode, which control the behavior of timestamps in addition to caching. Under InteropModeExclusive (analogous to cacheAll) and InteropModeWritethrough (analogous to cacheAllWritethrough), client timestamps are *not* written back to the server (it is not possible in 9P or Linux for clients to set ctime, so writing back client-authoritative timestamps results in incoherence between atime/mtime and ctime). Under InteropModeShared (analogous to cacheRemoteRevalidating), client timestamps are not used at all (remote filesystem clocks are authoritative). cacheNone is translated to InteropModeShared + new option filesystemOptions.specialRegularFiles. - Under InteropModeShared, "unstable attribute" reloading for permission checks, lookup, and revalidation are fused, which is feasible in VFS2 since gofer.filesystem controls path resolution. This results in a ~33% reduction in RPCs for filesystem operations compared to cacheRemoteRevalidating. For example, consider stat("/foo/bar/baz") where "/foo/bar/baz" fails revalidation, resulting in the instantiation of a new dentry: VFS1 RPCs: getattr("/") // fs.MountNamespace.FindLink() => fs.Inode.CheckPermission() => gofer.inodeOperations.check() => gofer.inodeOperations.UnstableAttr() walkgetattr("/", "foo") = fid1 // fs.Dirent.walk() => gofer.session.Revalidate() => gofer.cachePolicy.Revalidate() clunk(fid1) getattr("/foo") // CheckPermission walkgetattr("/foo", "bar") = fid2 // Revalidate clunk(fid2) getattr("/foo/bar") // CheckPermission walkgetattr("/foo/bar", "baz") = fid3 // Revalidate clunk(fid3) walkgetattr("/foo/bar", "baz") = fid4 // fs.Dirent.walk() => gofer.inodeOperations.Lookup getattr("/foo/bar/baz") // linux.stat() => gofer.inodeOperations.UnstableAttr() VFS2 RPCs: getattr("/") // gofer.filesystem.walkExistingLocked() walkgetattr("/", "foo") = fid1 // gofer.filesystem.stepExistingLocked() clunk(fid1) // No getattr: walkgetattr already updated metadata for permission check walkgetattr("/foo", "bar") = fid2 clunk(fid2) walkgetattr("/foo/bar", "baz") = fid3 // No clunk: fid3 used for new gofer.dentry // No getattr: walkgetattr already updated metadata for stat() - gofer.filesystem.unlinkAt() does not require instantiation of a dentry that represents the file to be deleted. Updates #898. - gofer.regularFileFD.OnClose() skips Tflushf for regular files under InteropModeExclusive, as it's nonsensical to request a remote file flush without flushing locally-buffered writes to that remote file first. - Symlink targets are cached when InteropModeShared is not in effect. - p9.QID.Path (which is already required to be unique for each file within a server, and is accordingly already synthesized from device/inode numbers in all known gofers) is used as-is for inode numbers, rather than being mapped along with attr.RDev in the client to yet another synthetic inode number. - Relevant parts of fsutil.CachingInodeOperations are inlined directly into gofer package code. This avoids having to duplicate part of its functionality in fsutil.HostMappable. PiperOrigin-RevId: 293190213
2020-01-31Implement file locks for regular tmpfs files in VFSv2.Dean Deng
Add a file lock implementation that can be embedded into various filesystem implementations. Updates #1480 PiperOrigin-RevId: 292614758
2020-01-28Add support for WritableSource in DynamicBytesFileDescriptionImplFabricio Voznika
WritableSource is a convenience interface used for files that can be written to, e.g. /proc/net/ipv4/tpc_sack. It reads max of 4KB and only from offset 0 which should cover most cases. It can be extended as neeed. Updates #1195 PiperOrigin-RevId: 292056924
2020-01-28Add //pkg/sentry/fsimpl/devtmpfs.Jamie Liu
PiperOrigin-RevId: 292021389
2020-01-27Update package locations.Adin Scannell
Because the abi will depend on the core types for marshalling (usermem, context, safemem, safecopy), these need to be flattened from the sentry directory. These packages contain no sentry-specific details. PiperOrigin-RevId: 291811289
2020-01-27Standardize on tools directory.Adin Scannell
PiperOrigin-RevId: 291745021
2020-01-24Add support for device special files to VFS2 tmpfs.Jamie Liu
PiperOrigin-RevId: 291471892
2020-01-22De-duplicate common test functionality for VFS2 filesystems.Rahat Mahmood
PiperOrigin-RevId: 291041576
2020-01-22Move VFS2 handling of FD readability/writability to vfs.FileDescription.Jamie Liu
PiperOrigin-RevId: 291006713
2020-01-21Implement sysfs.Rahat Mahmood
PiperOrigin-RevId: 290822487
2020-01-21Add line break to /proc/net filesFabricio Voznika
Some files were missing the last line break. PiperOrigin-RevId: 290808898
2020-01-17Add /proc/[pid]/cgroups fileFabricio Voznika
Updates #1195 PiperOrigin-RevId: 290298266
2020-01-17Add /proc/net/* filesFabricio Voznika
Updates #1195 PiperOrigin-RevId: 290285420
2020-01-16Implement tmpfs.SetStat with a size argument.Nicolas Lacasse
This is similar to 'Truncate' in vfs1. Updates https://github.com/google/gvisor/issues/1197 PiperOrigin-RevId: 290139140
2020-01-16Add more files to /proc/[pid]/*Fabricio Voznika
Files not implemented require VFSv2 plumbing into the kernel. Also, cgroup is not implemented yet. Updates #1195 PiperOrigin-RevId: 290129176
2020-01-16Add remaining /proc/* and /proc/sys/* filesFabricio Voznika
Except for one under /proc/sys/net/ipv4/tcp_sack. /proc/pid/* is still incomplete. Updates #1195 PiperOrigin-RevId: 290120438
2020-01-15Add timestamps to VFS2 tmpfs, and implement some of SetStat.Nicolas Lacasse
PiperOrigin-RevId: 289962040
2020-01-09New sync package.Ian Gudger
* Rename syncutil to sync. * Add aliases to sync types. * Replace existing usage of standard library sync package. This will make it easier to swap out synchronization primitives. For example, this will allow us to use primitives from github.com/sasha-s/go-deadlock to check for lock ordering violations. Updates #1472 PiperOrigin-RevId: 289033387
2020-01-08Define sizes for extent headers and entries separately to improve clarity.Dean Deng
PiperOrigin-RevId: 288799694
2020-01-08Make /proc/[pid] offset start at TGID_OFFSETFabricio Voznika
Updates #1195 PiperOrigin-RevId: 288725745
2020-01-06Convert memfs into proto-tmpfs.Nicolas Lacasse
- Renamed memfs to tmpfs. - Copied fileRangeSet bits from fs/fsutil/ to fsimpl/tmpfs/ - Changed tmpfs to be backed by filemem instead of byte slice. - regularFileReadWriter uses a sync.Pool, similar to gofer client. PiperOrigin-RevId: 288356380
2019-12-30Add VFS2 support for device special files.Jamie Liu
- Add FileDescriptionOptions.UseDentryMetadata, which reduces the amount of boilerplate needed for device FDs and the like between filesystems. - Switch back to having FileDescription.Init() take references on the Mount and Dentry; otherwise managing refcounts around failed calls to OpenDeviceSpecialFile() / Device.Open() is tricky. PiperOrigin-RevId: 287575574
2019-12-27Add VFS2 support for /proc/filesystems.Jamie Liu
Updates #1195 PiperOrigin-RevId: 287269106
2019-12-26Initial procfs implementation in VFSv2Fabricio Voznika
Updates #1195 PiperOrigin-RevId: 287227722
2019-12-23Fix deadlock in kernfs.Filesystem.revalidateChildLockedFabricio Voznika
It was calling Dentry.InsertChild with the dentry's mutex already locked. Updates #1035 PiperOrigin-RevId: 286962742
2019-12-23Clean up vfs.FilesystemImpl methods that operate on parent directories.Jamie Liu
- 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
2019-12-20Move VFS2 file description status flags to vfs.FileDescription.Jamie Liu
PiperOrigin-RevId: 286616668
2019-12-18Add VFS2 plumbing for extended attributes.Jamie Liu
PiperOrigin-RevId: 286281274
2019-12-18Add Mems_allowed to /proc/PID/statusMichael Pratt
PiperOrigin-RevId: 286248378
2019-12-12Implement kernfs.Rahat Mahmood
PiperOrigin-RevId: 285231002
2019-12-11Add vfs.Pathname{WithDeleted,ForGetcwd}.Jamie Liu
The former is needed for vfs.FileDescription to implement memmap.MappingIdentity, and the latter is needed to implement getcwd(2). PiperOrigin-RevId: 285051855
2019-12-10Add most VFS methods for syscalls.Jamie Liu
PiperOrigin-RevId: 284892289
2019-12-03Point TODOs to gvisor.devFabricio Voznika
PiperOrigin-RevId: 283610781
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
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