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2020-08-12Fix race in vfs.FileDescription.statusFlagFabricio Voznika
PiperOrigin-RevId: 326270643
2020-08-07Support separate read/write handles in fsimpl/gofer.dentry.Jamie Liu
PiperOrigin-RevId: 325490674
2020-08-03Plumbing context.Context to DecRef() and Release().Nayana Bidari
context is passed to DecRef() and Release() which is needed for SO_LINGER implementation. PiperOrigin-RevId: 324672584
2020-07-31Clean up vfs2 fallocate.Dean Deng
Move to setstat.go and add a FileDescription wrapper method. PiperOrigin-RevId: 324165277
2020-07-29Force registration for EPOLLHUP, not EPOLLRDHUP, in vfs2's epoll.Jamie Liu
Compare Linux's fs/eventpoll.c:do_epoll_ctl(). I don't know where EPOLLRDHUP came from. PiperOrigin-RevId: 323874419
2020-07-23Add permission checks to vfs2 truncate.Dean Deng
- Check write permission on truncate(2). Unlike ftruncate(2), truncate(2) fails if the user does not have write permissions on the file. - For gofers under InteropModeShared, check file type before making a truncate request. We should fail early and avoid making an rpc when possible. Furthermore, depending on the remote host's failure may give us unexpected behavior--if the host converts the truncate request to an ftruncate syscall on an open fd, we will get EINVAL instead of EISDIR. Updates #2923. PiperOrigin-RevId: 322913569
2020-07-23Added stub FUSE filesystemRidwan Sharif
Allow FUSE filesystems to be mounted using libfuse. The appropriate flags and mount options are parsed and understood by fusefs.
2020-07-13Clean up inotify comments.Dean Deng
PiperOrigin-RevId: 321028238
2020-07-08Add shared mount hints to VFS2Fabricio Voznika
Container restart test is disabled for VFS2 for now. Updates #1487 PiperOrigin-RevId: 320296401
2020-07-01Port fallocate to VFS2.Zach Koopmans
PiperOrigin-RevId: 319283715
2020-06-30Allow O_DIRECT on vfs2 tmpfs files.Dean Deng
Updates #2923. PiperOrigin-RevId: 319153792
2020-06-27Port GETOWN, SETOWN fcntls to vfs2.Dean Deng
Also make some fixes to vfs1's F_SETOWN. The fcntl test now entirely passes on vfs2. Fixes #2920. PiperOrigin-RevId: 318669529
2020-06-27Support sticky bit in vfs2.Dean Deng
Updates #2923. PiperOrigin-RevId: 318648128
2020-06-27Add documentation for vfs2 inotify.Dean Deng
Updates #1479. PiperOrigin-RevId: 318631247
2020-06-26Support inotify IN_ONESHOT.Dean Deng
Also, while we're here, make sure that gofer inotify events are generated when files are created in remote revalidating mode. Updates #1479. PiperOrigin-RevId: 318536354
2020-06-24Fix procfs bugs in vfs2.Dean Deng
- Support writing on proc/[pid]/{uid,gid}map - Return EIO for writing to static files. Updates #2923. PiperOrigin-RevId: 318188503
2020-06-23Resolve remaining inotify TODOs.Dean Deng
Also refactor HandleDeletion(). Updates #1479. PiperOrigin-RevId: 317989000
2020-06-23Complete inotify IN_EXCL_UNLINK implementation in VFS2.Dean Deng
Events were only skipped on parent directories after their children were unlinked; events on the unlinked file itself need to be skipped as well. As a result, all Watches.Notify() calls need to know whether the dentry where the call came from was unlinked. Updates #1479. PiperOrigin-RevId: 317979476
2020-06-23Support inotify in vfs2 gofer fs.Dean Deng
Because there is no inode structure stored in the sandbox, inotify watches must be held on the dentry. This would be an issue in the presence of hard links, where multiple dentries would need to share the same set of watches, but in VFS2, we do not support the internal creation of hard links on gofer fs. As a result, we make the assumption that every dentry corresponds to a unique inode. Furthermore, dentries can be cached and then evicted, even if the underlying file has not be deleted. We must prevent this from occurring if there are any watches that would be lost. Note that if the dentry was deleted or invalidated (d.vfsd.IsDead()), we should still destroy it along with its watches. Additionally, when a dentry’s last watch is removed, we cache it if it also has zero references. This way, the dentry can eventually be evicted from memory if it is no longer needed. This is accomplished with a new dentry method, OnZeroWatches(), which is called by Inotify.RmWatch and Inotify.Release. Note that it must be called after all inotify locks are released to avoid violating lock order. Stress tests are added to make sure that inotify operations don't deadlock with gofer.OnZeroWatches. Updates #1479. PiperOrigin-RevId: 317958034
2020-06-18Fix vfs2 tmpfs link permission checks.Dean Deng
Updates #2923. PiperOrigin-RevId: 317246916
2020-06-18Remove various uses of 'whitelist'Michael Pratt
Updates #2972 PiperOrigin-RevId: 317113059
2020-06-17Implement POSIX locksFabricio Voznika
- Change FileDescriptionImpl Lock/UnlockPOSIX signature to take {start,length,whence}, so the correct offset can be calculated in the implementations. - Create PosixLocker interface to make it possible to share the same locking code from different implementations. Closes #1480 PiperOrigin-RevId: 316910286
2020-06-11Add //pkg/sentry/fsimpl/overlay.Jamie Liu
Major differences from existing overlay filesystems: - Linux allows lower layers in an overlay to require revalidation, but not the upper layer. VFS1 allows the upper layer in an overlay to require revalidation, but not the lower layer. VFS2 does not allow any layers to require revalidation. (Now that vfs.MkdirOptions.ForSyntheticMountpoint exists, no uses of overlay in VFS1 are believed to require upper layer revalidation; in particular, the requirement that the upper layer support the creation of "trusted." extended attributes for whiteouts effectively required the upper filesystem to be tmpfs in most cases.) - Like VFS1, but unlike Linux, VFS2 overlay does not attempt to make mutations of the upper layer atomic using a working directory and features like RENAME_WHITEOUT. (This may change in the future, since not having a working directory makes error recovery for some operations, e.g. rmdir, particularly painful.) - Like Linux, but unlike VFS1, VFS2 represents whiteouts using character devices with rdev == 0; the equivalent of the whiteout attribute on directories is xattr trusted.overlay.opaque = "y"; and there is no equivalent to the whiteout attribute on non-directories since non-directories are never merged with lower layers. - Device and inode numbers work as follows: - In Linux, modulo the xino feature and a special case for when all layers are the same filesystem: - Directories use the overlay filesystem's device number and an ephemeral inode number assigned by the overlay. - Non-directories that have been copied up use the device and inode number assigned by the upper filesystem. - Non-directories that have not been copied up use a per-(overlay, layer)-pair device number and the inode number assigned by the lower filesystem. - In VFS1, device and inode numbers always come from the lower layer unless "whited out"; this has the adverse effect of requiring interaction with the lower filesystem even for non-directory files that exist on the upper layer. - In VFS2, device and inode numbers are assigned as in Linux, except that xino and the samefs special case are not supported. - Like Linux, but unlike VFS1, VFS2 does not attempt to maintain memory mapping coherence across copy-up. (This may have to change in the future, as users may be dependent on this property.) - Like Linux, but unlike VFS1, VFS2 uses the overlayfs mounter's credentials when interacting with the overlay's layers, rather than the caller's. - Like Linux, but unlike VFS1, VFS2 permits multiple lower layers in an overlay. - Like Linux, but unlike VFS1, VFS2's overlay filesystem is application-mountable. Updates #1199 PiperOrigin-RevId: 316019067
2020-06-09Implement flock(2) in VFS2Fabricio Voznika
LockFD is the generic implementation that can be embedded in FileDescriptionImpl implementations. Unique lock ID is maintained in vfs.FileDescription and is created on demand. Updates #1480 PiperOrigin-RevId: 315604825
2020-06-05Implement mount(2) and umount2(2) for VFS2.Rahat Mahmood
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
2020-06-03Take Mount reference in VFS.connectLocked.Jamie Liu
Updates #179 PiperOrigin-RevId: 314563830
2020-05-29Update Go version build tagsMichael Pratt
None of the dependencies have changed in 1.15. It may be possible to simplify some of the wrappers in rawfile following 1.13, but that can come in a later change. PiperOrigin-RevId: 313863264
2020-05-29Implement IN_EXCL_UNLINK inotify option in vfs2.Dean Deng
Limited to tmpfs. Inotify support in other filesystem implementations to follow. Updates #1479 PiperOrigin-RevId: 313828648
2020-05-29Port inotify to vfs2, with support in tmpfs.Dean Deng
Support in other filesystem impls is still needed. Unlike in Linux and vfs1, we need to plumb inotify down to each filesystem implementation in order to keep track of links/inode structures properly. IN_EXCL_UNLINK still needs to be implemented, as well as a few inotify hooks that are not present in either vfs1 or vfs2. Those will be addressed in subsequent changes. Updates #1479. PiperOrigin-RevId: 313781995
2020-05-28Split VFS.MountAt into VFS.MountDisconnected and VFS.ConnectMountAt.Jamie Liu
This makes it straightforward to create bind mounts internally in VFS2: Given a bind mount root represented by vfs.VirtualDentry vd: - Create a new mount with VFS.NewDisconnectedMount(vd.Mount().Filesystem(), vd.Dentry()). - Connect the resulting mount in the appropriate namespace with VFS.ConnectMountAt(). Note that the resulting bind mount is non-recursive; recursive bind mounting requires explicitly duplicating all children of the original mount, which is best handled internally by VFS. Updates #179 PiperOrigin-RevId: 313703963
2020-05-26Implement splice(2) and tee(2) for VFS2.Jamie Liu
Updates #138 PiperOrigin-RevId: 313326354
2020-05-07Allocate device numbers for VFS2 filesystems.Jamie Liu
Updates #1197, #1198, #1672 PiperOrigin-RevId: 310432006
2020-05-07Move pkg/sentry/vfs/{eventfd,timerfd} to new packages in pkg/sentry/fsimpl.Nicolas Lacasse
They don't depend on anything in VFS2, so they should be their own packages. PiperOrigin-RevId: 310416807
2020-05-07Port signalfd to vfs2.Nicolas Lacasse
PiperOrigin-RevId: 310404113
2020-05-07Remove outdated TODO for VFS2 AccessAt.Dean Deng
Fixes #1965. PiperOrigin-RevId: 310380433
2020-05-06Remove vfs.FileDescriptionOptions.InvalidWrite.Jamie Liu
Compare: https://elixir.bootlin.com/linux/v5.6/source/fs/timerfd.c#L431 PiperOrigin-RevId: 310246908
2020-05-04Port eventfd to VFS2.Nicolas Lacasse
And move sys_timerfd.go to just timerfd.go for consistency. Updates #1475. PiperOrigin-RevId: 309835029
2020-05-04Add TTY support on VFS2 to runscFabricio Voznika
Updates #1623, #1487 PiperOrigin-RevId: 309777922
2020-04-28Fix Unix socket permissions.Dean Deng
Enforce write permission checks in BoundEndpointAt, which corresponds to the permission checks in Linux (net/unix/af_unix.c:unix_find_other). Also, create bound socket files with the correct permissions in VFS2. Fixes #2324. PiperOrigin-RevId: 308949084
2020-04-28Support pipes and sockets in VFS2 gofer fs.Dean Deng
Named pipes and sockets can be represented in two ways in gofer fs: 1. As a file on the remote filesystem. In this case, all file operations are passed through 9p. 2. As a synthetic file that is internal to the sandbox. In this case, the dentry stores an endpoint or VFSPipe for sockets and pipes respectively, which replaces interactions with the remote fs through the gofer. In gofer.filesystem.MknodAt, we attempt to call mknod(2) through 9p, and if it fails, fall back to the synthetic version. Updates #1200. PiperOrigin-RevId: 308828161
2020-04-24Fixes for procfsFabricio Voznika
- Return ENOENT for /proc/[pid]/task if task is zoombied or terminated - Allow directory to be Seek() to the end - Construct synthetic files for /proc/[pid]/ns/* - Changed GenericDirectoryFD.Init to not register with FileDescription, otherwise other implementation cannot change behavior. Updates #1195,1193 PiperOrigin-RevId: 308294649
2020-04-23Add vfs.MkdirOptions.ForSyntheticMountpoint.Jamie Liu
PiperOrigin-RevId: 308143529
2020-04-21Misc VFS2 fixesFabricio Voznika
- Fix defer operation ordering in kernfs.Filesystem.AccessAt() - Add AT_NULL entry in proc/pid/auvx - Fix line padding in /proc/pid/maps - Fix linux_dirent serialization for getdents(2) - Remove file creation flags from vfs.FileDescription.statusFlags() Updates #1193, #1035 PiperOrigin-RevId: 307704159
2020-04-21Remove filesystem structure from vfs.Dentry.Jamie Liu
This change: - Drastically simplifies the synchronization model: filesystem structure is both implementation-defined and implementation-synchronized. - Allows implementations of vfs.DentryImpl to use implementation-specific dentry types, reducing casts during path traversal. - Doesn't require dentries representing non-directory files to waste space on a map of children. - Allows dentry revalidation and mount lookup to be correctly ordered (fixed FIXME in fsimpl/gofer/filesystem.go). - Removes the need to have two separate maps in gofer.dentry (dentry.vfsd.children and dentry.negativeChildren) for positive and negative lookups respectively. //pkg/sentry/fsimpl/tmpfs/benchmark_test.go: name old time/op new time/op delta VFS2TmpfsStat/1-112 172ns ± 4% 165ns ± 3% -4.08% (p=0.002 n=9+9) VFS2TmpfsStat/2-112 199ns ± 3% 195ns ±10% ~ (p=0.132 n=8+9) VFS2TmpfsStat/3-112 230ns ± 2% 216ns ± 2% -6.15% (p=0.000 n=8+8) VFS2TmpfsStat/8-112 390ns ± 2% 358ns ± 4% -8.33% (p=0.000 n=9+8) VFS2TmpfsStat/64-112 2.20µs ± 3% 2.01µs ± 3% -8.48% (p=0.000 n=10+8) VFS2TmpfsStat/100-112 3.42µs ± 9% 3.08µs ± 2% -9.82% (p=0.000 n=9+8) VFS2TmpfsMountStat/1-112 278ns ± 1% 286ns ±15% ~ (p=0.712 n=8+10) VFS2TmpfsMountStat/2-112 311ns ± 4% 298ns ± 2% -4.27% (p=0.000 n=9+8) VFS2TmpfsMountStat/3-112 339ns ± 3% 330ns ± 9% ~ (p=0.070 n=8+9) VFS2TmpfsMountStat/8-112 503ns ± 3% 466ns ± 3% -7.38% (p=0.000 n=8+8) VFS2TmpfsMountStat/64-112 2.53µs ±16% 2.17µs ± 7% -14.19% (p=0.000 n=10+9) VFS2TmpfsMountStat/100-112 3.60µs ± 4% 3.30µs ± 8% -8.33% (p=0.001 n=8+9) Updates #1035 PiperOrigin-RevId: 307655892
2020-04-16Implement pipe(2) and pipe2(2) for VFS2.Jamie Liu
Updates #1035 PiperOrigin-RevId: 306968644
2020-04-14Pass O_LARGEFILE in syscalls/linux/vfs2.openat.Jamie Liu
Needed for PipeTest_Flags: files opened by open() and openat() get O_LARGEFILE (on architectures with 64-bit off_t), but not FDs created by other syscalls such as pipe(). Updates #1035 PiperOrigin-RevId: 306504788
2020-04-10Port extended attributes to VFS2.Dean Deng
As in VFS1, we only support the user.* namespace. Plumbing is added to tmpfs and goferfs. Note that because of the slightly different order of checks between VFS2 and Linux, one of the xattr tests needs to be relaxed slightly. Fixes #2363. PiperOrigin-RevId: 305985121
2020-04-08Clean up TODOsFabricio Voznika
PiperOrigin-RevId: 305592245
2020-04-06Port timerfd to VFS2.Nicolas Lacasse
PiperOrigin-RevId: 305067208
2020-04-04Record VFS2 sockets in global socket map.Dean Deng
Updates #1476, #1478, #1484, #1485. PiperOrigin-RevId: 304845354