gvisor/pkg/sentry/fsimpl/gofer/BUILD

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VFS2 gofer client 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
2020-02-04 19:28:36 +00:00
load("//tools:defs.bzl", "go_library")
load("//tools/go_generics:defs.bzl", "go_template_instance")
licenses(["notice"])
go_template_instance(
name = "dentry_list",
out = "dentry_list.go",
package = "gofer",
prefix = "dentry",
template = "//pkg/ilist:generic_list",
types = {
"Element": "*dentry",
"Linker": "*dentry",
},
)
go_library(
name = "gofer",
srcs = [
"dentry_list.go",
"directory.go",
"filesystem.go",
"gofer.go",
"handle.go",
"handle_unsafe.go",
"p9file.go",
"pagemath.go",
"regular_file.go",
"special_file.go",
"symlink.go",
"time.go",
],
visibility = ["//pkg/sentry:internal"],
deps = [
"//pkg/abi/linux",
"//pkg/context",
"//pkg/fd",
"//pkg/fspath",
"//pkg/log",
"//pkg/p9",
"//pkg/safemem",
"//pkg/sentry/fs/fsutil",
"//pkg/sentry/kernel/auth",
"//pkg/sentry/kernel/time",
"//pkg/sentry/memmap",
"//pkg/sentry/pgalloc",
"//pkg/sentry/platform",
"//pkg/sentry/usage",
"//pkg/sentry/vfs",
"//pkg/syserror",
"//pkg/unet",
"//pkg/usermem",
],
)