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path: root/pkg/p9/handlers.go
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2020-12-07Remove p9.fidRef.openedMuMichael Pratt
openedMu has lock ordering violations. Most locks go through OpenedFlag(), which is usually taken after renameMu and opMu. On the other hand, Tlopen takes openedMu before renameMu and opMu (via safelyRead). Resolving this violation is simple: just drop openedMu. The opened and openFlags fields are already protected by opMu in most cases, renameMu (for write) in one case (via safelyGlobal), and only in doWalk by neither. This is a bit ugly because opMu is supposed to be a "semantic" lock, but it works. I'm open to other suggestions. Note that doWalk has a race condition where a FID may open after the open check but before actually walking. This race existed before this change as well; it is not clear if it is problematic. PiperOrigin-RevId: 346108483
2020-09-01Implement setattr+clunk in 9PFabricio Voznika
This is to cover the common pattern: open->read/write->close, where SetAttr needs to be called to update atime/mtime before the file is closed. Benchmark results: BM_OpenReadClose/10240 CPU setattr+clunk: 63783 ns VFS2: 68109 ns VFS1: 72507 ns Updates #1198 PiperOrigin-RevId: 329628461
2020-04-09Handle os.LinkError in p9/handlers.go.Dean Deng
PiperOrigin-RevId: 305721329
2020-04-06Add concurrency guarantees to p9 extended attribute methods.Dean Deng
PiperOrigin-RevId: 305171772
2020-02-07Support listxattr and removexattr syscalls.Dean Deng
Note that these are only implemented for tmpfs, and other impls will still return EOPNOTSUPP. PiperOrigin-RevId: 293899385
2020-01-16Plumb getting/setting xattrs through InodeOperations and 9p gofer interfaces.Dean Deng
There was a very bare get/setxattr in the InodeOperations interface. Add context.Context to both, size to getxattr, and flags to setxattr. Note that extended attributes are passed around as strings in this implementation, so size is automatically encoded into the value. Size is added in getxattr so that implementations can return ERANGE if a value is larger than can fit in the user-allocated buffer. This prevents us from unnecessarily passing around an arbitrarily large xattr when the user buffer is actually too small. Don't use the existing xattrwalk and xattrcreate messages and define our own, mainly for the sake of simplicity. Extended attributes will be implemented in future commits. PiperOrigin-RevId: 290121300
2019-12-16Remove useless comments from p9/handlers.go.Nicolas Lacasse
These comments provided nothing, and have been copy-pasted into all implementations. The code is clear without them. I considered also removing the "handle implements handler.handle" comments, but will let those stay for now. PiperOrigin-RevId: 285876428
2019-11-20Pass OpenTruncate to gofer in Open call when opening file with O_TRUNC.Nicolas Lacasse
Note that the Sentry still calls Truncate() on the file before calling Open. A new p9 version check was added to ensure that the p9 server can handle the the OpenTruncate flag. If not, then the flag is stripped before sending. PiperOrigin-RevId: 281609112
2019-09-12Update p9 to support flipcall.Adin Scannell
PiperOrigin-RevId: 268845090
2019-06-21Remove O(n) lookup on unlink/renameMichael Pratt
Currently, the path tracking in the gofer involves an O(n) lookup of child fidRefs. This causes a significant overhead on unlinks in directories with lots of child fidRefs (<4k). In this transition, pathNode moves from sync.Map to normal synchronized maps. There is a small chance of contention in walk, but the lock is held for a very short time (and sync.Map also had a chance of requiring locking). OTOH, sync.Map makes it very difficult to add a fidRef reverse map. PiperOrigin-RevId: 254489952
2019-06-21Update pathNode documentation to reflect realityMichael Pratt
Neither fidRefs or children are (directly) synchronized by mu. Remove the preconditions that say so. That said, the surrounding does enforce some synchronization guarantees (e.g., fidRef.renameChildTo does not atomically replace the child in the maps). I've tried to note the need for callers to do this synchronization. I've also renamed the maps to what are (IMO) clearer names. As is, it is not obvious that pathNode.fidRefs is a map of *child* fidRefs rather than self fidRefs. PiperOrigin-RevId: 254446965
2019-06-13Update canonical repository.Adin Scannell
This can be merged after: https://github.com/google/gvisor-website/pull/77 or https://github.com/google/gvisor-website/pull/78 PiperOrigin-RevId: 253132620
2019-05-20Forward named pipe creation to the goferMichael Pratt
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
2019-05-09Implement fallocate(2)Fabricio Voznika
Closes #225 PiperOrigin-RevId: 247508791 Change-Id: I04f47cf2770b30043e5a272aba4ba6e11d0476cc
2019-04-29Change copyright notice to "The gVisor Authors"Michael Pratt
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
2019-02-28Fix typoMichael Pratt
PiperOrigin-RevId: 236239090 Change-Id: I92e63d6f4b52b78852626c87743fdd86175e09d3
2019-02-25Don't call WalkGetAttr for walk(names=[]).Jamie Liu
PiperOrigin-RevId: 235587729 Change-Id: I37074416b10a30ca3a00d11bcde338d8d979beaf
2019-02-15Internal change.Googler
PiperOrigin-RevId: 234169795 Change-Id: I3c576ae6ad460e2c0e3f142a2671dc18d34a07ef
2018-10-23Remove artificial name length check.Adin Scannell
This should be determined by the filesystem. PiperOrigin-RevId: 218376553 Change-Id: I55d176e2cdf8acdd6642789af057b98bb8ca25b8
2018-10-23Track paths and provide a rename hook.Adin Scannell
This change also adds extensive testing to the p9 package via mocks. The sanity checks and type checks are moved from the gofer into the core package, where they can be more easily validated. PiperOrigin-RevId: 218296768 Change-Id: I4fc3c326e7bf1e0e140a454cbacbcc6fd617ab55
2018-10-19Use correct company name in copyright headerIan Gudger
PiperOrigin-RevId: 217951017 Change-Id: Ie08bf6987f98467d07457bcf35b5f1ff6e43c035
2018-09-07Add additional sanity checks for walk.Adin Scannell
PiperOrigin-RevId: 212058684 Change-Id: I319709b9ffcfccb3231bac98df345d2a20eca24b
2018-08-13Add path sanity checks.Adin Scannell
PiperOrigin-RevId: 208527333 Change-Id: I55291bc6b8bc6b88fdd75baf899a71854c39c1a7
2018-04-28Check in gVisor.Googler
PiperOrigin-RevId: 194583126 Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463
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