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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] 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 fallocate to VFS2.Zach Koopmans
PiperOrigin-RevId: 319283715
2020-06-30Allow O_DIRECT on vfs2 tmpfs files.Dean Deng
Updates #2923. PiperOrigin-RevId: 319153792
2020-06-27Support sticky bit in vfs2.Dean Deng
Updates #2923. PiperOrigin-RevId: 318648128
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
2020-06-19Fix bugs in vfs2 to make symlink tests pass.Dean Deng
- Return ENOENT if target path is empty. - Make sure open(2) with O_CREAT|O_EXCL returns EEXIST when necessary. - Correctly update atime in tmpfs using touchATime(). Updates #2923. PiperOrigin-RevId: 317382655
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
2020-06-18Fix vfs2 tmpfs link permission checks.Dean Deng
Updates #2923. PiperOrigin-RevId: 317246916
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
2020-06-09Implement 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
2020-06-08Implement VFS2 tmpfs mount options.Jamie Liu
As in VFS1, the mode, uid, and gid options are supported. Updates #1197 PiperOrigin-RevId: 315340510
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
2020-05-29Implement 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
2020-05-27Correctly update link and ref counts in rmdir.Dean Deng
Inotify sends events when a watch target is reaches a link count of 0 (see include/linux/fsnotify.h:fsnotify_inoderemove). Currently, we do not account for both dir/ and dir/.. in unlink, causing syscalls/linux/inotify.cc:WatchTargetDeletionGeneratesEvent to fail because the expected inotify events are not generated. Furthermore, we should DecRef() once the inode reaches zero links; otherwise, we will leak a reference. PiperOrigin-RevId: 313502091
2020-05-26Implement splice(2) and tee(2) for VFS2.Jamie Liu
Updates #138 PiperOrigin-RevId: 313326354
2020-05-14Port memfd_create to vfs2 and finish implementation of file seals.Nicolas Lacasse
Closes #2612. PiperOrigin-RevId: 311548074
2020-05-13Resolve remaining TODOs for tmpfs.Nicolas Lacasse
Closes #1197 PiperOrigin-RevId: 311438223
2020-05-07Allocate device numbers for VFS2 filesystems.Jamie Liu
Updates #1197, #1198, #1672 PiperOrigin-RevId: 310432006
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
2020-04-21Remove 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
2020-04-20Change lingering uses of "memfs" in fsimpl/tmpfs to "tmpfs".Jamie Liu
PiperOrigin-RevId: 307422746
2020-04-16Implement pipe(2) and pipe2(2) for VFS2.Jamie Liu
Updates #1035 PiperOrigin-RevId: 306968644
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
2020-04-08Fix all printf formatting errors.Adin Scannell
Updates #2243
2020-04-06Add socket files to tmpfs VFS2.Dean Deng
Updates #1476. PiperOrigin-RevId: 305024274
2020-04-02Add NAME_MAX checks and update file timesFabricio Voznika
NAME_MAX should be enforced per filesystem implementation because other file systems may not have the same restriction. Gofer filesystem now keeps a reference to the kernel clock to avoid lookup in the Context on file access to update atime. Update access, modification, and status change times in tmpfs. Updates #1197, #1198. PiperOrigin-RevId: 304527148
2020-04-02Fix typo in TODO comments.Dean Deng
PiperOrigin-RevId: 304508083
2020-04-01Pass configurable FilesystemType to tmpfs.Nicolas Lacasse
PiperOrigin-RevId: 304234086
2020-03-31Allow passing root file type to tmpfs.Nicolas Lacasse
PiperOrigin-RevId: 304053357
2020-03-27Add FilesystemType.Name method, and FilesystemType field to Filesystem struct.Nicolas Lacasse
Both have analogues in Linux: * struct file_system_type has a char *name field. * struct super_block keeps a pointer to the file_system_type. These fields are necessary to support the `filesystem type` field in /proc/[pid]/mountinfo. PiperOrigin-RevId: 303434063
2020-03-26Add BoundEndpointAt filesystem operation.Dean Deng
BoundEndpointAt() is needed to support Unix sockets bound at a file path, corresponding to BoundEndpoint() in VFS1. Updates #1476. PiperOrigin-RevId: 303258251
2020-03-26Combine file mode and isDir argumentsFabricio Voznika
Updates #1035 PiperOrigin-RevId: 303021328
2020-03-25Set file mode and type to attributeFabricio Voznika
Makes less error prone to find file type. Updates #1197 PiperOrigin-RevId: 302974244
2020-03-16Enforce file size rlimits in VFS2Fabricio Voznika
Updates #1035 PiperOrigin-RevId: 301255357
2020-03-16Add calls to vfs.CheckSetStat to fsimplsFabricio Voznika
Only gofer filesystem was calling vfs.CheckSetStat for vfs.FilesystemImpl.SetStatAt and vfs.FileDescriptionImpl.SetStat. Updates #1193, #1672, #1197 PiperOrigin-RevId: 301226522
2020-03-13Implement access/faccessat for VFS2.Dean Deng
Note that the raw faccessat system call does not actually take a flags argument; according to faccessat(2), the glibc wrapper implements the flags by using fstatat(2). Remove the flag argument that we try to extract from vfs1, which would just be a garbage value. Updates #1965 Fixes #2101 PiperOrigin-RevId: 300796067
2020-02-20VFS2: Support memory mapping in tmpfs.gVisor bot
tmpfs.fileDescription now implements ConfigureMMap. And tmpfs.regularFile implement memmap.Mappable. The methods are mostly unchanged from VFS1 tmpfs. PiperOrigin-RevId: 296234557
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
2020-02-04Remove 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 //pkg/sentry/fsimpl/devtmpfs.Jamie Liu
PiperOrigin-RevId: 292021389