The backing 9p server must allow named pipe creation, which the runsc
fsgofer currently does not.
There are small changes to the overlay here. GetFile may block when
opening a named pipe, which can cause a deadlock:
1. open(O_RDONLY) -> copyMu.Lock() -> GetFile()
2. open(O_WRONLY) -> copyMu.Lock() -> Deadlock
A named pipe usable for writing must already be on the upper filesystem,
but we are still taking copyMu for write when checking for upper. That
can be changed to a read lock to fix the common case.
However, a named pipe on the lower filesystem would still deadlock in
open(O_WRONLY) when it tries to actually perform copy up (which would
simply return EINVAL). Move the copy up type check before taking copyMu
for write to avoid this.
p9 must be modified, as it was incorrectly removing the file mode when
sending messages on the wire.
PiperOrigin-RevId: 249154033
Change-Id: Id6637130e567b03758130eb6c7cdbc976384b7d6
* Creation of files, directories (and other fs objects) in a directory
should always update ctime.
* Same for removal.
* atime should not be updated on lookup, only readdir.
I've also renamed some misleading functions that update mtime and ctime.
PiperOrigin-RevId: 249115063
Change-Id: I30fa275fa7db96d01aa759ed64628c18bb3a7dc7
There is a lot of redundancy that we can simplify in the stat_times
test. This will make it easier to add new tests. However, the
simplification reveals that cached uattrs on goferfs don't properly
update ctime on rename.
PiperOrigin-RevId: 248773425
Change-Id: I52662728e1e9920981555881f9a85f9ce04041cf
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
Maximum filename length is filesystem-dependent, and obtained via
statfs::f_namelen. This limit is usually 255 bytes (NAME_MAX), but not
always. For example, VFAT supports filenames of up to 255... UCS-2
characters, which Linux conservatively takes to mean UTF-8-encoded
bytes: fs/fat/inode.c:fat_statfs(), FAT_LFN_LEN * NLS_MAX_CHARSET_SIZE.
As a result, Linux's VFS does not enforce NAME_MAX:
$ rg --maxdepth=1 '\WNAME_MAX\W' fs/ include/linux/
fs/libfs.c
38: buf->f_namelen = NAME_MAX;
64: if (dentry->d_name.len > NAME_MAX)
include/linux/relay.h
74: char base_filename[NAME_MAX]; /* saved base filename */
include/linux/fscrypt.h
149: * filenames up to NAME_MAX bytes, since base64 encoding expands the length.
include/linux/exportfs.h
176: * understanding that it is already pointing to a a %NAME_MAX+1 sized
Remove this check from core VFS, and add it to ramfs (and by extension
tmpfs), where it is actually applicable:
mm/shmem.c:shmem_dir_inode_operations.lookup == simple_lookup *does*
enforce NAME_MAX.
PiperOrigin-RevId: 245324748
Change-Id: I17567c4324bfd60e31746a5270096e75db963fac
- Document fsutil.CachedFileObject.FD() requirements on access
permissions, and change gofer.inodeFileState.FD() to honor them.
Fixes#147.
- Combine gofer.inodeFileState.readonly and
gofer.inodeFileState.readthrough, and simplify handle caching logic.
- Inline gofer.cachePolicy.cacheHandles into
gofer.inodeFileState.setSharedHandles, because users with access to
gofer.inodeFileState don't necessarily have access to the fs.Inode
(predictably, this is a save/restore problem).
Before this CL:
$ docker run --runtime=runsc-d -v $(pwd)/gvisor/repro:/root/repro -it ubuntu bash
root@34d51017ed67:/# /root/repro/runsc-b147
mmap: 0x7f3c01e45000
Segmentation fault
After this CL:
$ docker run --runtime=runsc-d -v $(pwd)/gvisor/repro:/root/repro -it ubuntu bash
root@d3c3cb56bbf9:/# /root/repro/runsc-b147
mmap: 0x7f78987ec000
o
PiperOrigin-RevId: 240818413
Change-Id: I49e1d4a81a0cb9177832b0a9f31a10da722a896b
In the case of a rename replacing an existing destination inode, ramfs
Rename failed to first remove the replaced inode. This caused:
1. A leak of a reference to the inode (making it live indefinitely).
2. For directories, a leak of the replaced directory's .. link to the
parent. This would cause the parent's link count to incorrectly
increase.
(2) is much simpler to test than (1), so that's what I've done.
agentfs has a similar bug with link count only, so the Dirent layer
informs the Inode if this is a replacing rename.
Fixes#133
PiperOrigin-RevId: 239105698
Change-Id: I4450af2462d8ae3339def812287213d2cbeebde0
p9.Twalk.handle() with a non-empty path also stats the walked-to path
anyway, so the preceding GetAttr is completely wasted.
PiperOrigin-RevId: 238440645
Change-Id: I7fbc7536f46b8157639d0d1f491e6aaa9ab688a3
When file size changes outside the sandbox, page cache was not
refreshing file size which is required for cacheRemoteRevalidating.
In fact, cacheRemoteRevalidating should be skipping the cache
completely since it's not really benefiting from it. The cache is
cache is already bypassed for unstable attributes (see
cachePolicy.cacheUAttrs). And althought the cache is called to
map pages, they will always miss the cache and map directly from
the host.
Created a HostMappable struct that maps directly to the host and
use it for files with cacheRemoteRevalidating.
Closes#124
PiperOrigin-RevId: 230998440
Change-Id: Ic5f632eabe33b47241e05e98c95e9b2090ae08fc
The cache policy determines whether Lookup should return a negative dirent, or
just ENOENT. This CL fixes one spot where we returned a negative dirent without
first consulting the policy.
PiperOrigin-RevId: 208280230
Change-Id: I8f963bbdb45a95a74ad0ecc1eef47eff2092d3a4
Previously, processes which used file-system Unix Domain Sockets could not be
checkpoint-ed in runsc because the sockets were saved with their inode
numbers which do not necessarily remain the same upon restore. Now,
the sockets are also saved with their paths so that the new inodes
can be determined for the sockets based on these paths after restoring.
Tests for cases with UDS use are included. Test cleanup to come.
PiperOrigin-RevId: 208268781
Change-Id: Ieaa5d5d9a64914ca105cae199fd8492710b1d7ec
Dirent.FullName takes the global renameMu, but can be called during Create,
which itself takes dirent.mu and dirent.dirMu, which is a lock-order violation:
Dirent.Create
d.dirMu.Lock
d.mu.Lock
Inode.Create
gofer.inodeOperations.Create
gofer.NewFile
Dirent.FullName
d.renameMu.RLock
We only use the FullName here for logging, and in this case we can get by with
logging only the BaseName.
A `BaseName` method was added to Dirent, which simply returns the name, taking
d.parent.mu as required.
In the Create pathway, we can't call d.BaseName() because taking d.parent.mu
after d.mu violates the lock order. But we already know the base name of the
file we just created, so that's OK.
In the Open/GetFile pathway, we are free to call d.BaseName() because the other
dirent locks are not held.
PiperOrigin-RevId: 205112278
Change-Id: Ib45c734081aecc9b225249a65fa8093eb4995f10
The new policy is identical to FSCACHE (which caches everything in memory), but
it also flushes writes to the backing fs agent immediately.
All gofer cache policy decisions have been moved into the cachePolicy type.
Previously they were sprinkled around the codebase.
There are many different things that we cache (page cache, negative dirents,
dirent LRU, unstable attrs, readdir results....), and I don't think we should
have individual flags to control each of these. Instead, we should have a few
high-level cache policies that are consistent and useful to users. This
refactoring makes it easy to add more such policies.
PiperOrigin-RevId: 201206937
Change-Id: I6e225c382b2e5e1b0ad4ccf8ca229873f4cd389d
Michael Pratt
Andrei Vagin
Jamie Liu
Fabricio Voznika
Ian Gudger
Nicolas Lacasse
Brielle Broder
Googler