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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
2020-07-27Move platform.File in memmapAndrei Vagin
The subsequent systrap changes will need to import memmap from the platform package. PiperOrigin-RevId: 323409486
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
2020-07-23[vfs2][gofer] Fix update attributes race condition.Ayush Ranjan
We were getting the file attributes before locking the metadataMu which was causing stale updates to the file attributes. Fixes OpenTest_AppendConcurrentWrite. Updates #2923 PiperOrigin-RevId: 322804438
2020-07-22Add O_APPEND support in vfs2 gofer.Ayush Ranjan
Helps in fixing open syscall tests: AppendConcurrentWrite and AppendOnly. We also now update the file size for seekable special files (regular files) which we were not doing earlier. Updates #2923 PiperOrigin-RevId: 322670843
2020-07-14Update special file option name in comment.Dean Deng
PiperOrigin-RevId: 321269281
2020-07-13[vfs2] Make gofer metadata atomics consistentAyush Ranjan
For accessing metadata fields: - If metadataMu is locked, we can access without atomics - If metadataMu is unlocked, we should use atomics For mutating metadata fields: - Always lock metadataMu and use atomics. There were some instances of inconsistencies which have been fixed. PiperOrigin-RevId: 321022895
2020-07-06Call fdnotifier.UpdateFD() from fsimpl/gofer.specialFileFD.Jamie Liu
The fdnotifier package provides an API to a thread that continually epolls arbitrary host FDs. The set of events polled for each host FD is (intended to be) all events for which a waiter.Entry has expressed interest, as returned by waiter.Queue.Events() for the waiter.Queue registered to the given host FD. When the set of events changes (due to a change in the set of registered waiter.Entries), the mutator must call fdnotifier.UpdateFD() to recalculate the new event set and propagate it to the epoll FD. PiperOrigin-RevId: 319924719
2020-07-06Ensure sync is called for readonly fileFabricio Voznika
Calling sync on a readonly file flushes metadata that may have been modified, like last access time. Updates #1198 PiperOrigin-RevId: 319888290
2020-07-06Add inode number to synthetic dentriesFabricio Voznika
Reserve the MSB from ino for synthetic dentries to prevent conflict with regular dentries. Log warning in case MSB is set for regular dentries. Updates #1487 PiperOrigin-RevId: 319869858
2020-07-01Update preadv2/pwritev2 flag handling in vfs2.Dean Deng
We do not support RWF_SYNC/RWF_DSYNC and probably shouldn't silently accept them, since the user may incorrectly believe that we are synchronizing I/O. Remove the pwritev2 test verifying that we support these flags. gvisor.dev/issue/2601 is the tracking bug for deciding which RWF_.* flags we need and supporting them. Updates #2923, #2601. PiperOrigin-RevId: 319351286
2020-07-01[vfs2][gofer] Fix mmap syscall test.Ayush Ranjan
We were not invalidating mappings when the file size changed in shared mode. Enabled the syscall test for vfs2. Updates #2923 PiperOrigin-RevId: 319346569
2020-07-01[vfs2][gofer] Update file size to 0 on O_TRUNCAyush Ranjan
Some Open:TruncateXxx syscall tests were failing because the file size was not being updated when the file was opened with O_TRUNC. Fixes Truncate tests in test/syscalls:open_test_runsc_ptrace_vfs2. Updates #2923 PiperOrigin-RevId: 319340127
2020-07-01Port vfs1 implementation of sync_file_range to vfs2.Dean Deng
Currently, we always perform a full-file sync which could be extremely expensive for some applications. Although vfs1 did not fully support sync_file_range, there were some optimizations that allowed us skip some unnecessary write-outs. Updates #2923, #1897. PiperOrigin-RevId: 319324213
2020-07-01Port fallocate to VFS2.Zach Koopmans
PiperOrigin-RevId: 319283715
2020-06-27Support sticky bit in vfs2.Dean Deng
Updates #2923. PiperOrigin-RevId: 318648128
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
2020-06-23Complete 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
2020-06-22Check for invalid trailing / when traversing path in gofer OpenAt.Dean Deng
Updates #2923. PiperOrigin-RevId: 317700049
2020-06-21Fix vfs2 extended attributes.Dean Deng
Correct behavior when given zero size arguments and trying to set user.* xattrs on files other than regular files or directories. Updates #2923. PiperOrigin-RevId: 317590409
2020-06-19Fix vfs2 handling of preadv2/pwritev2 flags.Dean Deng
Check for unsupported flags, and silently support RWF_HIPRI by doing nothing. From pkg/abi/linux/file.go: "gVisor does not implement the RWF_HIPRI feature, but the flag is accepted as a valid flag argument for preadv2/pwritev2." Updates #2923. PiperOrigin-RevId: 317330631
2020-06-19Don't adjust parent link count if we replace a child dir with another.Dean Deng
Updates #2923. PiperOrigin-RevId: 317314460
2020-06-19Support all seek options in gofer specialFileFD.Seek.Dean Deng
Updates #2923. PiperOrigin-RevId: 317298186
2020-06-19Fix synthetic file bugs in gofer fs.Dean Deng
Always check if a synthetic file already exists at a location before creating a file there, and do not try to delete synthetic gofer files from the remote fs. This fixes runsc_ptrace socket tests that create/unlink synthetic, named socket files. Updates #2923. PiperOrigin-RevId: 317293648
2020-06-17Implement Sync() to directoriesFabricio Voznika
Updates #1035, #1199 PiperOrigin-RevId: 317028108
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
2020-06-16Miscellaneous VFS2 fixes.Jamie Liu
PiperOrigin-RevId: 316627764
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
2020-06-01Fix VFS2 gofer open(O_CREAT) reference leak.Jamie Liu
gofer.filesystem.createAndOpenChildLocked() doesn't need to take a reference on the new dentry since vfs.FileDescription.Init() will do so. PiperOrigin-RevId: 314242127
2020-06-01Handle gofer blocking opens of host named pipes in VFS2.Jamie Liu
Using tee instead of read to detect when a O_RDONLY|O_NONBLOCK pipe FD has a writer circumvents the problem of what to do with the byte read from the pipe, avoiding much of the complexity of the fdpipe package. PiperOrigin-RevId: 314216146
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
2020-05-26Support dfltuid and dfltgid mount options in the VFS2 gofer client.Jamie Liu
PiperOrigin-RevId: 313332542
2020-05-19Implement mmap for host fs in vfs2.Dean Deng
In VFS1, both fs/host and fs/gofer used the same utils for host file mappings. Refactor parts of fsimpl/gofer to create similar utils to share with fsimpl/host (memory accounting code moved to fsutil, page rounding arithmetic moved to usermem). Updates #1476. PiperOrigin-RevId: 312345090
2020-05-14Make utimes_test pass on VFS2.Jamie Liu
PiperOrigin-RevId: 311657502
2020-05-13Enable overlayfs_stale_read by default for runsc.Jamie Liu
Linux 4.18 and later make reads and writes coherent between pre-copy-up and post-copy-up FDs representing the same file on an overlay filesystem. However, memory mappings remain incoherent: - Documentation/filesystems/overlayfs.rst, "Non-standard behavior": "If a file residing on a lower layer is opened for read-only and then memory mapped with MAP_SHARED, then subsequent changes to the file are not reflected in the memory mapping." - fs/overlay/file.c:ovl_mmap() passes through to the underlying FD without any management of coherence in the overlay. - Experimentally on Linux 5.2: ``` $ cat mmap_cat_page.c #include <err.h> #include <fcntl.h> #include <stdio.h> #include <string.h> #include <sys/mman.h> #include <unistd.h> int main(int argc, char **argv) { if (argc < 2) { errx(1, "syntax: %s [FILE]", argv[0]); } const int fd = open(argv[1], O_RDONLY); if (fd < 0) { err(1, "open(%s)", argv[1]); } const size_t page_size = sysconf(_SC_PAGE_SIZE); void* page = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0); if (page == MAP_FAILED) { err(1, "mmap"); } for (;;) { write(1, page, strnlen(page, page_size)); if (getc(stdin) == EOF) { break; } } return 0; } $ gcc -O2 -o mmap_cat_page mmap_cat_page.c $ mkdir lowerdir upperdir workdir overlaydir $ echo old > lowerdir/file $ sudo mount -t overlay -o "lowerdir=lowerdir,upperdir=upperdir,workdir=workdir" none overlaydir $ ./mmap_cat_page overlaydir/file old ^Z [1]+ Stopped ./mmap_cat_page overlaydir/file $ echo new > overlaydir/file $ cat overlaydir/file new $ fg ./mmap_cat_page overlaydir/file old ``` Therefore, while the VFS1 gofer client's behavior of reopening read FDs is only necessary pre-4.18, replacing existing memory mappings (in both sentry and application address spaces) with mappings of the new FD is required regardless of kernel version, and this latter behavior is common to both VFS1 and VFS2. Re-document accordingly, and change the runsc flag to enabled by default. New test: - Before this CL: https://source.cloud.google.com/results/invocations/5b222d2c-e918-4bae-afc4-407f5bac509b - After this CL: https://source.cloud.google.com/results/invocations/f28c747e-d89c-4d8c-a461-602b33e71aab PiperOrigin-RevId: 311361267
2020-05-11Internal change.Jamie Liu
PiperOrigin-RevId: 311046755
2020-05-11Add fsimpl/gofer.InternalFilesystemOptions.OpenSocketsByConnecting.Jamie Liu
PiperOrigin-RevId: 311014995
2020-05-07Allocate device numbers for VFS2 filesystems.Jamie Liu
Updates #1197, #1198, #1672 PiperOrigin-RevId: 310432006
2020-05-05Update comments for synthetic gofer files in vfs2.Dean Deng
PiperOrigin-RevId: 309966538
2020-05-05Translate p9.NoUID/GID to OverflowUID/GID.Jamie Liu
p9.NoUID/GID (== uint32(-1) == auth.NoID) is not a valid auth.KUID/KGID; in particular, using it for file ownership causes capabilities to be ineffective since file capabilities require that the file's KUID and KGID are mapped into the capability holder's user namespace [1], and auth.NoID is not mapped into any user namespace. Map p9.NoUID/GID to a different, valid KUID/KGID; in the unlikely case that an application actually using the overflow KUID/KGID attempts an operation that is consequently permitted by client permission checks, the remote operation will still fail with EPERM. Since this changes the VFS2 gofer client to no longer ignore the invalid IDs entirely, this CL both permits and requires that we change synthetic mount point creation to use root credentials. [1] See fs.Inode.CheckCapability or vfs.GenericCheckPermissions. PiperOrigin-RevId: 309856455
2020-05-01Port netstack, hostinet, and netlink sockets to VFS2.Dean Deng
All three follow the same pattern: 1. Refactor VFS1 sockets into socketOpsCommon, so that most of the methods can be shared with VFS2. 2. Create a FileDescriptionImpl with the corresponding socket operations, rewriting the few that cannot be shared with VFS1. 3. Set up a VFS2 socket provider that creates a socket by setting up a dentry in the global Kernel.socketMount and connecting it with a new FileDescription. This mostly completes the work for porting sockets to VFS2, and many syscall tests can be enabled as a result. There are several networking-related syscall tests that are still not passing: 1. net gofer tests 2. socketpair gofer tests 2. sendfile tests (splice is not implemented in VFS2 yet) Updates #1478, #1484, #1485 PiperOrigin-RevId: 309457331
2020-04-30Add gofer.InternalFilesystemOptions.LeakConnection.Jamie Liu
PiperOrigin-RevId: 309317605
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
2020-04-24VFS2: Get HelloWorld image tests to pass with VFS2Zach Koopmans
This change includes: - Modifications to loader_test.go to get TestCreateMountNamespace to pass with VFS2. - Changes necessary to get TestHelloWorld in image tests to pass with VFS2. This means runsc can run the hello-world container with docker on VSF2. Note: Containers that use sockets will not run with these changes. See "//test/image/...". Any tests here with sockets currently fail (which is all of them but HelloWorld). PiperOrigin-RevId: 308363072
2020-04-23Add vfs.MkdirOptions.ForSyntheticMountpoint.Jamie Liu
PiperOrigin-RevId: 308143529
2020-04-23Factor fsimpl/gofer.host{Preadv,Pwritev} out of fsimpl/gofer.Jamie Liu
Also fix returning EOF when 0 bytes are read. PiperOrigin-RevId: 308089875