VFS2 is adding more functionality than VFS1. In order to test
new functionality, it's required to skip some tests with VFS1.
To skip tests, use:
SKIP_IF(IsRunningWithVFS1());
The test will run in Linux and gVisor with VFS2 enabled.
Updates #1035
PiperOrigin-RevId: 312698616
This change was derived from a change by:
Reapor-Yurnero <reapor.yurnero@gmail.com>
And has been modified by:
Adin Scannell <ascannell@google.com>
(The original change author is preserved for the commit.)
This change implements gap tracking in the segment set by adding additional
information in each node, and using that information to speed up gap finding
from a linear scan to a O(log(n)) walk of the tree.
This gap tracking is optional, and will default to off except for segment
instances that set gapTracking equal to 1 in their const lists.
PiperOrigin-RevId: 312621607
These packages don't actually use go_stateify or go_marshal, but end
up implicitly dependent on the respective packages due to our build
rules.
These unnecessary dependencies make them unusuable in certain contexts
due to circular dependency.
PiperOrigin-RevId: 312595738
If there is a Timestamps option in the arriving segment and SEG.TSval
< TS.Recent and if TS.Recent is valid, then treat the arriving segment
as not acceptable: Send an acknowledgement in reply as specified in
RFC-793 page 69 and drop the segment.
https://tools.ietf.org/html/rfc1323#page-19
PiperOrigin-RevId: 312590678
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
With additional logging, the issue described by the new comment looks like:
D0518 21:28:08.416810 6777 task_signals.go:459] [ 8] Notified of signal 27
D0518 21:28:08.416852 6777 task_block.go:223] [ 8] Interrupt queued
D0518 21:28:08.417013 6777 task_run.go:250] [ 8] Switching to sentry
D0518 21:28:08.417033 6777 task_signals.go:220] [ 8] Signal 27: delivering to handler
D0518 21:28:08.417127 6777 task_run.go:248] [ 8] Switching to app
D0518 21:28:08.443765 6777 task_signals.go:519] [ 8] Refusing masked signal 27 // ED: note the ~26ms elapsed since TID 8 "switched to app"
D0518 21:28:08.443814 6777 task_signals.go:465] [ 6] Notified of group signal 27
D0518 21:28:08.443832 6777 task_block.go:223] [ 6] Interrupt queued
D0518 21:28:08.443914 6777 task_block.go:223] [ 6] Interrupt queued
D0518 21:28:08.443859 6777 task_run.go:250] [ 8] Switching to sentry
I0518 21:28:08.443936 6777 strace.go:576] [ 8] exe E rt_sigreturn()
Slow context switches on ptrace are probably due to kernel scheduling delays.
Slow context switches on KVM are less clear, so leave that bug and TODO open.
PiperOrigin-RevId: 312322782
On native Linux, calling recv/read right after send/write sometimes returns
EWOULDBLOCK, if the data has not made it to the receiving socket (even though
the endpoints are on the same host). Poll before reading to avoid this.
Making this change also uncovered a hostinet bug (gvisor.dev/issue/2726),
which is noted in this CL.
PiperOrigin-RevId: 312320587
* Aggregate architecture Overview in "What is gVisor?" as it makes more sense
in one place.
* Drop "user-space kernel" and use "application kernel". The term "user-space
kernel" is confusing when some platform implementation do not run in
user-space (instead running in guest ring zero).
* Clear up the relationship between the Platform page in the user guide and the
Platform page in the architecture guide, and ensure they are cross-linked.
* Restore the call-to-action quick start link in the main page, and drop the
GitHub link (which also appears in the top-right).
* Improve image formatting by centering all doc and blog images, and move the
image captions to the alt text.
PiperOrigin-RevId: 311845158
As per RFC 1122 and Linux retransmit timeout handling:
- The segment retransmit timeout needs to exponentially increase and
cap at a predefined value.
- TCP connection needs to timeout after a predefined number of
segment retransmissions.
- TCP connection should not timeout when the retranmission timeout
exceeds MaxRTO, predefined upper bound.
Fixes#2673
PiperOrigin-RevId: 311463961
This change adds support for TCP_SYNCNT and TCP_WINDOW_CLAMP options
in GetSockOpt/SetSockOpt. This change does not really change any
behaviour in Netstack and only stores/returns the stored value.
Actual honoring of these options will be added as required.
Fixes#2626, #2625
PiperOrigin-RevId: 311453777
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
gVisor bot
Mikael Mello
Geethanjali Eswaran
Dean Deng
Jamie Liu
Fabricio Voznika
Reapor-Yurnero
Jay Zhuang
Rahat Mahmood
Zeling Feng
Ian Lewis
Nicolas Lacasse
Adin Scannell
Bhasker Hariharan
Mithun Iyer
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