These inodes can never be part of a filesystem tree. They are nameless and
never have a parent.
This allows us to avoid taking a lock in kernfs.InotifyWithParent for such
anonymous inodes.
PiperOrigin-RevId: 538823227
Some implementations handle more flags than others, so it doesn't
make sense to have one set of rules for all.
This change should functionally be a no-op.
PiperOrigin-RevId: 502712415
This is consistent with Linux. Some applications recursively add
files to inotify FD. They fail if they run into kernfs files
because inotify_add_watch(2) returns EPERM in that case.
PiperOrigin-RevId: 462642204
Update all instances of the above errors to the faster linuxerr implementation.
With the temporary linuxerr.Equals(), no logical changes are made.
PiperOrigin-RevId: 382306655
Split usermem package to help remove syserror dependency in go_marshal.
New hostarch package contains code not dependent on syserror.
PiperOrigin-RevId: 365651233
The default pipe size already matched linux, and is unchanged.
Furthermore `atomicIOBytes` is made a proper constant (as it is in Linux). We
were plumbing usermem.PageSize everywhere, so this is no functional change.
PiperOrigin-RevId: 340497006
Singleton filesystem like devpts and devtmpfs have a single filesystem shared
among all mounts, so they acquire a "self-reference" when initialized that
must be released when the entire virtual filesystem is released at sandbox
exit.
PiperOrigin-RevId: 336828852
This change aims to fix the memory leak issue reported in #3933.
Background:
VFS2 kernfs kept accumulating invalid dentries if those dentries were not
walked on. After substantial consideration of the problem by our team, we
decided to have an LRU cache solution. This change is the first part to that
solution, where we don't cache anything. The LRU cache can be added on top of
this.
What has changed:
- Introduced the concept of an inode tree in kernfs.OrderedChildren.
This is helpful is cases where the lifecycle of an inode is different from
that of a dentry.
- OrderedChildren now deals with initialized inodes instead of initialized
dentries. It now implements Lookup() where it constructs a new dentry
using the inode.
- OrderedChildren holds a ref on all its children inodes. With this change,
now an inode can "outlive" a dentry pointing to it. See comments in
kernfs.OrderedChildren.
- The kernfs dentry tree is solely maintained by kernfs only. Inode
implementations can not modify the dentry tree.
- Dentries that reach ref count 0 are removed from the dentry tree.
- revalidateChildLocked now defer-DecRefs the newly created dentry from
Inode.Lookup(), limiting its life to the current filesystem operation. If
refs are picked on the dentry during the FS op (via an FD or something),
then it will stick around and will be removed when the FD is closed. So there
is essentially _no caching_ for Look()ed up dentries.
- kernfs.DecRef does not have the precondition that fs.mu must be locked.
Fixes#3933
PiperOrigin-RevId: 336768576
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
- 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
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
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