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2020-09-27Fix kernfs race condition.Dean Deng
Do not release dirMu between checking whether to create a child and actually inserting it. Also fixes a bug in fusefs which was causing it to deadlock under the new lock ordering. We do not need to call kernfs.Dentry.InsertChild from newEntry because it will always be called at the kernfs filesystem layer. Updates #1193. PiperOrigin-RevId: 334049264
2020-09-24[vfs] kernfs: Do not hold reference on the inode when opening FD.Ayush Ranjan
The FD should hold a reference on the dentry they were opened on which in turn holds a reference on the inode it points to. PiperOrigin-RevId: 333589223
2020-09-24[vfs] [2/2] kernfs: kernfs: Internally use kernfs.Dentry instead of vfs.Dentry.Ayush Ranjan
Update signatures for: - All methods in inodeDirectory - deferDecRef() and Filesystem.droppedDentries - newSyntheticDirectory() - `slot`s used in OrderedChildren and subsequent methods like replaceChildLocked() and checkExistingLocked() - stepExistingLocked(), walkParentDirLocked(), checkCreateLocked() Updates #1193 PiperOrigin-RevId: 333558866
2020-09-24Add basic stateify annotations.Adin Scannell
Updates #1663 PiperOrigin-RevId: 333539293
2020-09-23[vfs] kernfs: Enable leak checking consistently.Ayush Ranjan
There were some instances where we were not enabling leak checking. PiperOrigin-RevId: 333418571
2020-09-22[vfs] [1/2] kernfs: Internally use kernfs.Dentry instead of vfs.Dentry.Ayush Ranjan
Update signatures for: - walkExistingLocked - checkDeleteLocked - Inode.Open Updates #1193 PiperOrigin-RevId: 333163381
2020-09-21Use kernfs.Dentry for kernfs.Lookup.Dean Deng
Updates #1193. PiperOrigin-RevId: 332939026
2020-09-18Merge pull request #3972 from btw616:fix/commentsgVisor bot
PiperOrigin-RevId: 332486111
2020-09-17Fix kernfs unlinkat and rmdirat incorrect resolved path nameJinmou Li
2020-09-17fsimpl: improve the "implements" commentsTiwei Bie
As noticed by @ayushr2, the "implements" comments are not consistent, e.g. // IterDirents implements kernfs.inodeDynamicLookup. // Generate implements vfs.DynamicBytesSource.Generate. This patch improves this by making the comments like this consistently include the package name (when the interface and struct are not in the same package) and method name. Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
2020-09-16Implement FUSE_UNLINKBoyuan He
Fixes #3696
2020-09-16Implement FUSE_SETATTRCraig Chi
This commit implements FUSE_SETATTR command. When a system call modifies the metadata of a regular file or a folder by chown(2), chmod(2), truncate(2), utime(2), or utimes(2), they should be translated to corresponding FUSE_SETATTR command and sent to the FUSE server. Fixes #3332
2020-09-16fuse: Implement IterDirents for directory file descriptionRidwan Sharif
Fixes #3255. This change adds support for IterDirents. You can now use `ls` in the FUSE sandbox. Co-authored-by: Craig Chi <craigchi@google.com>
2020-09-16Implement FUSE_RMDIRRidwan Sharif
Fixes #3587 Co-authored-by: Craig Chi <craigchi@google.com>
2020-09-16Implement FUSE_READLINKBoyuan He
Fixes #3316
2020-09-16Implement FUSE_LOOKUPAndrei Vagin
Fixes #3231 Co-authored-by: Boyuan He <heboyuan@google.com>
2020-09-15Support setting STATX_SIZE for kernfs.InodeAttrs.Dean Deng
Make setting STATX_SIZE a no-op, if it is valid for the given permissions and file type. Also update proc tests, which were overfitted before. Fixes #3842. Updates #1193. PiperOrigin-RevId: 331861087
2020-09-08Implement synthetic mountpoints for kernfs.Jamie Liu
PiperOrigin-RevId: 330629897
2020-09-08Honor readonly flag for root mountFabricio Voznika
Updates #1487 PiperOrigin-RevId: 330580699
2020-09-08[vfs] Capitalize x in the {Get/Set/Remove/List}xattr functions.Ayush Ranjan
PiperOrigin-RevId: 330554450
2020-08-28Implement StatFS for various VFS2 filesystems.Rahat Mahmood
This mainly involved enabling kernfs' client filesystems to provide a StatFS implementation. Fixes #3411, #3515. PiperOrigin-RevId: 329009864
2020-08-25Use new reference count utility throughout gvisor.Dean Deng
This uses the refs_vfs2 template in vfs2 as well as objects common to vfs1 and vfs2. Note that vfs1-only refcounts are not replaced, since vfs1 will be deleted soon anyway. The following structs now use the new tool, with leak check enabled: devpts:rootInode fuse:inode kernfs:Dentry kernfs:dir kernfs:readonlyDir kernfs:StaticDirectory proc:fdDirInode proc:fdInfoDirInode proc:subtasksInode proc:taskInode proc:tasksInode vfs:FileDescription vfs:MountNamespace vfs:Filesystem sys:dir kernel:FSContext kernel:ProcessGroup kernel:Session shm:Shm mm:aioMappable mm:SpecialMappable transport:queue And the following use the template, but because they currently are not leak checked, a TODO is left instead of enabling leak check in this patch: kernel:FDTable tun:tunEndpoint Updates #1486. PiperOrigin-RevId: 328460377
2020-08-21Clarify seek behaviour for kernfs.GenericDirectoryFD.Rahat Mahmood
- Remove comment about GenericDirectoryFD not being compatible with dynamic directories. It is currently being used to implement dynamic directories. - Try to handle SEEK_END better than setting the offset to infinity. SEEK_END is poorly defined for dynamic directories anyways, so at least try make it work correctly for the static entries. Updates #1193. PiperOrigin-RevId: 327890128
2020-08-20Consistent precondition formattingMichael Pratt
Our "Preconditions:" blocks are very useful to determine the input invariants, but they are bit inconsistent throughout the codebase, which makes them harder to read (particularly cases with 5+ conditions in a single paragraph). I've reformatted all of the cases to fit in simple rules: 1. Cases with a single condition are placed on a single line. 2. Cases with multiple conditions are placed in a bulleted list. This format has been added to the style guide. I've also mentioned "Postconditions:", though those are much less frequently used, and all uses already match this style. PiperOrigin-RevId: 327687465
2020-08-18Get rid of kernfs.Inode.Destroy.Dean Deng
This interface method is unneeded. PiperOrigin-RevId: 327370325
2020-08-18Avoid holding locks when opening files in VFS2.Jamie Liu
Fixes #3243, #3521 PiperOrigin-RevId: 327308890
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
2020-07-23Add 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
2020-07-23FileDescription is hard to spell.Dean Deng
Fix typos. PiperOrigin-RevId: 322913282
2020-07-14Include context in kernfs.Inode.Stat methodCraig Chi
To implement stat(2) in FUSE, we have to embed credentials and pid in request header. The information should be extracted from the context passed to VFS layer. Therefore `Stat()` signature in `kernfs.Inode` interface should include context as first argument. Some other fs implementations need to be modified as well, such as devpts, host, pipefs, and proc. Fixes #3235
2020-07-13Merge pull request #2672 from amscanne:shim-integratedgVisor bot
PiperOrigin-RevId: 321053634
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
2020-06-24Fix 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
2020-06-23Support 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 vfs2 proc/self/fd dirent iteration.Dean Deng
Make proc/self/fd iteration work properly. Also, the comment on kernfs.Inode.IterDirents did not accurately reflect how parameters should be used/were used in kernfs.Inode impls other than fdDir. Updates #2923. PiperOrigin-RevId: 317370325
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
2020-05-29Implement 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
2020-05-29Fix the smallest of typos.Dean Deng
PiperOrigin-RevId: 313817646
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
2020-05-07Allocate device numbers for VFS2 filesystems.Jamie Liu
Updates #1197, #1198, #1672 PiperOrigin-RevId: 310432006
2020-05-05Return correct name for imported host filesFabricio Voznika
Implement PrependPath() in host.filesystem to correctly format name for host files. Updates #1672 PiperOrigin-RevId: 309959135
2020-05-04Remove kernfs.Filesystem cast from GenericDirectoryFDFabricio Voznika
This allows for kerfs.Filesystem to be overridden by different implementations. Updates #1672 PiperOrigin-RevId: 309809321
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
2020-04-24Plumb context.Context into kernfs.Inode.Open().Dean Deng
PiperOrigin-RevId: 308304793
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