A FUSE filesystem daemon runs in userland and is allowed to do very slow stuff, like access the network, for any operation. Accordingly, any syscall that waits on a response from the daemon should be interruptible, so any unresponsive daemon won't cause a system hang. The FUSE protocol includes a mechanism for interrupting operations. It's described in detail in doc/kernel.txt within the libfuse sources. Our driver currently doesn't implement it, but it should.
+100
A commit references this bug: Author: asomers Date: Thu Mar 14 17:20:26 UTC 2019 New revision: 345140 URL: https://svnweb.freebsd.org/changeset/base/345140 Log: fuse(4): add tests for FUSE_INTERRUPT This required changing the way that all operations are mocked. Previously MockFS::process had one input argument and one output argument. Now, it returns a vector of zero or more responses. This allows tests to simulate conditions where the filesystem daemon has a queue depth > 1. PR: 236530 Sponsored by: The FreeBSD Foundation Changes: projects/fuse2/tests/sys/fs/fuse/Makefile projects/fuse2/tests/sys/fs/fuse/create.cc projects/fuse2/tests/sys/fs/fuse/fsync.cc projects/fuse2/tests/sys/fs/fuse/getattr.cc projects/fuse2/tests/sys/fs/fuse/interrupt.cc projects/fuse2/tests/sys/fs/fuse/link.cc projects/fuse2/tests/sys/fs/fuse/locks.cc projects/fuse2/tests/sys/fs/fuse/lookup.cc projects/fuse2/tests/sys/fs/fuse/mkdir.cc projects/fuse2/tests/sys/fs/fuse/mknod.cc projects/fuse2/tests/sys/fs/fuse/mockfs.cc projects/fuse2/tests/sys/fs/fuse/mockfs.hh projects/fuse2/tests/sys/fs/fuse/open.cc projects/fuse2/tests/sys/fs/fuse/opendir.cc projects/fuse2/tests/sys/fs/fuse/read.cc projects/fuse2/tests/sys/fs/fuse/readdir.cc projects/fuse2/tests/sys/fs/fuse/readlink.cc projects/fuse2/tests/sys/fs/fuse/releasedir.cc projects/fuse2/tests/sys/fs/fuse/rmdir.cc projects/fuse2/tests/sys/fs/fuse/setattr.cc projects/fuse2/tests/sys/fs/fuse/statfs.cc projects/fuse2/tests/sys/fs/fuse/symlink.cc projects/fuse2/tests/sys/fs/fuse/utils.cc projects/fuse2/tests/sys/fs/fuse/write.cc
A commit references this bug: Author: asomers Date: Wed Apr 17 23:32:40 UTC 2019 New revision: 346339 URL: https://svnweb.freebsd.org/changeset/base/346339 Log: fusefs: WIP making FUSE operations interruptible The fuse protocol includes a FUSE_INTERRUPT operation that the client can send to the server to indicate that it wants to abort an in-progress operation. It's required to interrupt any syscall that is blocking on a fuse operation. This commit adds basic FUSE_INTERRUPT support. If a process receives any signal while it's blocking on a FUSE operation, it will send a FUSE_INTERRUPT and wait for the original operation to complete. But there is still much to do: * The current code will leak memory if the server ignores FUSE_INTERRUPT, which many do. It will also leak memory if the server completes the original operation before it receives the FUSE_INTERRUPT. * An interrupted read(2) will incorrectly appear to be successful. * fusefs should return immediately for fatal signals. * Operations that haven't been sent to the server yet should be aborted without sending FUSE_INTERRUPT. * Test coverage should be better. * It would be great if write operations could be made restartable. That would require delaying uiomove until the last possible moment, which would be sometime during fuse_device_read. PR: 236530 Sponsored by: The FreeBSD Foundation Changes: projects/fuse2/sys/fs/fuse/fuse_device.c projects/fuse2/sys/fs/fuse/fuse_io.c projects/fuse2/sys/fs/fuse/fuse_ipc.c projects/fuse2/sys/fs/fuse/fuse_ipc.h projects/fuse2/tests/sys/fs/fusefs/interrupt.cc projects/fuse2/tests/sys/fs/fusefs/mockfs.cc
A commit references this bug: Author: asomers Date: Thu Apr 18 19:16:36 UTC 2019 New revision: 346357 URL: https://svnweb.freebsd.org/changeset/base/346357 Log: fusefs: improvements to interruptibility * If a process receives a fatal signal while blocked on a fuse operation, return ASAP without waiting for the operation to complete. But still send the FUSE_INTERRUPT op to the daemon. * Plug memory leaks from r346339 Interruptibility is now fully functional, but it could be better: * Operations that haven't been sent to the server yet should be aborted without sending FUSE_INTERRUPT. * It would be great if write operations could be made restartable. That would require delaying uiomove until the last possible moment, which would be sometime during fuse_device_read. * It would be nice if we didn't have to guess which EAGAIN responses were for FUSE_INTERRUPT operations. PR: 236530 Sponsored by: The FreeBSD Foundation Changes: projects/fuse2/sys/fs/fuse/fuse_device.c projects/fuse2/sys/fs/fuse/fuse_ipc.c projects/fuse2/sys/fs/fuse/fuse_ipc.h projects/fuse2/tests/sys/fs/fusefs/allow_other.cc projects/fuse2/tests/sys/fs/fusefs/interrupt.cc projects/fuse2/tests/sys/fs/fusefs/open.cc projects/fuse2/tests/sys/fs/fusefs/utils.cc projects/fuse2/tests/sys/fs/fusefs/utils.hh
A commit references this bug: Author: asomers Date: Fri Apr 19 20:31:13 UTC 2019 New revision: 346417 URL: https://svnweb.freebsd.org/changeset/base/346417 Log: fusefs: fix interrupting FUSE_SETXATTR fusefs's VOP_SETEXTATTR calls uiomove(9) before blocking, so it can't be restarted. It must be interrupted instead. PR: 236530 Sponsored by: The FreeBSD Foundation Changes: projects/fuse2/sys/fs/fuse/fuse_vnops.c projects/fuse2/tests/sys/fs/fusefs/interrupt.cc
A commit references this bug: Author: asomers Date: Fri Apr 19 21:50:24 UTC 2019 New revision: 346418 URL: https://svnweb.freebsd.org/changeset/base/346418 Log: fusefs: give priority to FUSE_INTERRUPT operations When interrupting a FUSE operation, send the FUSE_INTERRUPT op to the daemon ASAP, ahead of other unrelated operations. PR: 236530 Sponsored by: The FreeBSD Foundation Changes: projects/fuse2/sys/fs/fuse/fuse_internal.c projects/fuse2/sys/fs/fuse/fuse_ipc.c projects/fuse2/sys/fs/fuse/fuse_ipc.h projects/fuse2/sys/fs/fuse/fuse_vnops.c projects/fuse2/tests/sys/fs/fusefs/interrupt.cc
Ok, this should be done now. There are only two problems remaining, and they're mere annoyances, not bugs: * VOP_WRITE and VOP_SETEXTATTR aren't restartable * The daemon won't see any error if it responds EAGAIN to a nonexistent ticket.
A commit references this bug: Author: asomers Date: Wed Aug 7 00:38:30 UTC 2019 New revision: 350665 URL: https://svnweb.freebsd.org/changeset/base/350665 Log: fusefs: merge from projects/fuse2 This commit imports the new fusefs driver. It raises the protocol level from 7.8 to 7.23, fixes many bugs, adds a test suite for the driver, and adds many new features. New features include: * Optional kernel-side permissions checks (-o default_permissions) * Implement VOP_MKNOD, VOP_BMAP, and VOP_ADVLOCK * Allow interrupting FUSE operations * Support named pipes and unix-domain sockets in fusefs file systems * Forward UTIME_NOW during utimensat(2) to the daemon * kqueue support for /dev/fuse * Allow updating mounts with "mount -u" * Allow exporting fusefs file systems over NFS * Server-initiated invalidation of the name cache or data cache * Respect RLIMIT_FSIZE * Try to support servers as old as protocol 7.4 Performance enhancements include: * Implement FUSE's FOPEN_KEEP_CACHE and FUSE_ASYNC_READ flags * Cache file attributes * Cache lookup entries, both positive and negative * Server-selectable cache modes: writethrough, writeback, or uncached * Write clustering * Readahead * Use counter(9) for statistical reporting PR: 199934 216391 233783 234581 235773 235774 235775 PR: 236226 236231 236236 236291 236329 236381 236405 PR: 236327 236466 236472 236473 236474 236530 236557 PR: 236560 236844 237052 237181 237588 238565 Reviewed by: bcr (man pages) Reviewed by: cem, ngie, rpokala, glebius, kib, bde, emaste (post-commit review on project branch) MFC after: 3 weeks Relnotes: yes Sponsored by: The FreeBSD Foundation Pull Request: https://reviews.freebsd.org/D21110 Changes: _U head/ head/MAINTAINERS head/UPDATING head/etc/mtree/BSD.tests.dist head/sbin/mount_fusefs/mount_fusefs.8 head/sbin/mount_fusefs/mount_fusefs.c head/share/man/man5/fusefs.5 head/sys/fs/fuse/fuse.h head/sys/fs/fuse/fuse_device.c head/sys/fs/fuse/fuse_file.c head/sys/fs/fuse/fuse_file.h head/sys/fs/fuse/fuse_internal.c head/sys/fs/fuse/fuse_internal.h head/sys/fs/fuse/fuse_io.c head/sys/fs/fuse/fuse_io.h head/sys/fs/fuse/fuse_ipc.c head/sys/fs/fuse/fuse_ipc.h head/sys/fs/fuse/fuse_kernel.h head/sys/fs/fuse/fuse_main.c head/sys/fs/fuse/fuse_node.c head/sys/fs/fuse/fuse_node.h head/sys/fs/fuse/fuse_param.h head/sys/fs/fuse/fuse_vfsops.c head/sys/fs/fuse/fuse_vnops.c head/sys/sys/param.h head/tests/sys/fs/Makefile head/tests/sys/fs/fusefs/
A commit references this bug: Author: asomers Date: Sun Sep 15 04:14:36 UTC 2019 New revision: 352351 URL: https://svnweb.freebsd.org/changeset/base/352351 Log: MFC the new fusefs driver MFC r350665, r350990, r350992, r351039, r351042, r351061, r351066, r351113, r351560, r351961, r351963, r352021, r352025, r352230 r350665: fusefs: merge from projects/fuse2 This commit imports the new fusefs driver. It raises the protocol level from 7.8 to 7.23, fixes many bugs, adds a test suite for the driver, and adds many new features. New features include: * Optional kernel-side permissions checks (-o default_permissions) * Implement VOP_MKNOD, VOP_BMAP, and VOP_ADVLOCK * Allow interrupting FUSE operations * Support named pipes and unix-domain sockets in fusefs file systems * Forward UTIME_NOW during utimensat(2) to the daemon * kqueue support for /dev/fuse * Allow updating mounts with "mount -u" * Allow exporting fusefs file systems over NFS * Server-initiated invalidation of the name cache or data cache * Respect RLIMIT_FSIZE * Try to support servers as old as protocol 7.4 Performance enhancements include: * Implement FUSE's FOPEN_KEEP_CACHE and FUSE_ASYNC_READ flags * Cache file attributes * Cache lookup entries, both positive and negative * Server-selectable cache modes: writethrough, writeback, or uncached * Write clustering * Readahead * Use counter(9) for statistical reporting PR: 199934 216391 233783 234581 235773 235774 235775 PR: 236226 236231 236236 236291 236329 236381 236405 PR: 236327 236466 236472 236473 236474 236530 236557 PR: 236560 236844 237052 237181 237588 238565 Reviewed by: bcr (man pages) Reviewed by: cem, ngie, rpokala, glebius, kib, bde, emaste (post-commit review on project branch) Relnotes: yes Sponsored by: The FreeBSD Foundation Pull Request: https://reviews.freebsd.org/D21110 r350990: fusefs: add SVN Keywords to the test files Reported by: SVN pre-commit hooks MFC-With: r350665 Sponsored by: The FreeBSD Foundation r350992: fusefs: skip some tests when unsafe aio is disabled MFC-With: r350665 Sponsored by: The FreeBSD Foundation r351039: fusefs: fix intermittency in the default_permissions.Unlink.ok test The test needs to expect a FUSE_FORGET operation. Most of the time the test would pass anyway, because by chance FUSE_FORGET would arrive after the unmount. MFC-With: 350665 Sponsored by: The FreeBSD Foundation r351042: fusefs: Fix the size of fuse_getattr_in In FUSE protocol 7.9, the size of the FUSE_GETATTR request has increased. However, the fusefs driver is currently not sending the additional fields. In our implementation, the additional fields are always zero, so I there haven't been any test failures until now. But fusefs-lkl requires the request's length to be correct. Fix this bug, and also enhance the test suite to catch similar bugs. PR: 239830 MFC-With: 350665 Sponsored by: The FreeBSD Foundation r351061: fusefs: fix the 32-bit build after 351042 Reported by: jhb MFC-With: 351042 Sponsored by: The FreeBSD Foundation r351066: fusefs: fix conditional from r351061 The entirety of r351061 was a copy/paste error. I'm sorry I've been comitting so hastily. Reported by: rpokala Reviewed by: rpokala MFC-With: 351061 Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21265 r351113: fusefs: don't send the namespace during listextattr The FUSE_LISTXATTR operation always returns the full list of a file's extended attributes, in all namespaces. There's no way to filter the list server-side. However, currently FreeBSD's fusefs driver sends a namespace string with the FUSE_LISTXATTR request. That behavior was probably copied from fuse_vnop_getextattr, which has an attribute name argument. It's been there ever since extended attribute support was added in r324620. This commit removes it. Reviewed by: cem Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21280 r351560: fusefs: Fix some bugs regarding the size of the LISTXATTR list * A small error in r338152 let to the returned size always being exactly eight bytes too large. * The FUSE_LISTXATTR operation works like Linux's listxattr(2): if the caller does not provide enough space, then the server should return ERANGE rather than return a truncated list. That's true even though in FUSE's case the kernel doesn't provide space to the client at all; it simply requests a maximum size for the list. We previously weren't handling the case where the server returns ERANGE even though the kernel requested as much size as the server had told us it needs; that can happen due to a race. * We also need to ensure that a pathological server that always returns ERANGE no matter what size we request in FUSE_LISTXATTR won't cause an infinite loop in the kernel. As of this commit, it will instead cause an infinite loop that exits and enters the kernel on each iteration, allowing signals to be processed. Reviewed by: cem Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21287 r351961: Coverity fixes in fusefs(5) CID 1404532 fixes a signed vs unsigned comparison error in fuse_vnop_bmap. It could potentially have resulted in VOP_BMAP reporting too many consecutive blocks. CID 1404364 is much worse. It was an array access by an untrusted, user-provided variable. It could potentially have resulted in a malicious file system crashing the kernel or worse. Reported by: Coverity Reviewed by: emaste Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21466 r351963: fusefs: coverity cleanup in the tests Address the following defects reported by Coverity: * Structurally dead code (CID 1404366): set m_quit before FAIL, not after * Unchecked return value of sysctlbyname (CID 1404321) * Unchecked return value of stat(2) (CID 1404471) * Unchecked return value of open(2) (CID 1404402, 1404529) * Unchecked return value of dup(2) (CID 1404478) * Buffer overflows. These are all false positives caused by the fact that Coverity thinks I'm using a buffer to store strings, when in fact I'm really just using it to store a byte array that happens to be initialized with a string. I'm changing the type from char to uint8_t in the hopes that it will placate Coverity. (CID 1404338, 1404350, 1404367, 1404376, 1404379, 1404381, 1404388, 1404403, 1404425, 1404433, 1404434, 1404474, 1404480, 1404484, 1404503, 1404505) * False positive file descriptor leak. I'm going to try to fix this with Coverity modeling, but I'll also change an EXPECT to ASSERT so we don't perform meaningless assertions after the failure. (CID 1404320, 1404324, 1404440, 1404445). * Unannotated file descriptor leak. This will be followed up by a Coverity modeling change. (CID 1404326, 1404334, 1404336, 1404357, 1404361, 1404372, 1404391, 1404395, 1404409, 1404430, 1404448, 1404451, 1404455, 1404457, 1404458, 1404460) * Uninitialized variables in C++ constructors (CID 1404327, 1404346). In the case of m_maxphys, this actually led to part of the FUSE_INIT's response being set to stack garbage during the WriteCluster::clustering test. * Uninitialized sun_len field in struct sockaddr_un (CID 1404330, 1404371, 1404429). Reported by: Coverity Reviewed by: emaste Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21457 r352021: fusefs: suppress some Coverity resource leak CIDs in the tests The fusefs tests deliberately leak file descriptors. To do otherwise would add extra complications to the tests' mock FUSE server. This annotation should hopefully convince Coverity to shut up about the leaks. Reviewed by: uqs Sponsored by: The FreeBSD Foundation r352025: mount_fusefs: fix a segfault on memory allocation failure Reported by: Coverity Coverity CID: 1354188 Sponsored by: The FreeBSD Foundation r352230: fusefs: Fix iosize for FUSE_WRITE in 7.8 compat mode When communicating with a FUSE server that implements version 7.8 (or older) of the FUSE protocol, the FUSE_WRITE request structure is 16 bytes shorter than normal. The protocol version check wasn't applied universally, leading to an extra 16 bytes being sent to such servers. The extra bytes were allocated and bzero()d, so there was no information disclosure. Reviewed by: emaste MFC-With: r350665 Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21557 Changes: _U stable/12/ stable/12/MAINTAINERS stable/12/UPDATING stable/12/etc/mtree/BSD.tests.dist stable/12/sbin/mount_fusefs/mount_fusefs.8 stable/12/sbin/mount_fusefs/mount_fusefs.c stable/12/share/man/man5/fusefs.5 stable/12/sys/fs/fuse/fuse.h stable/12/sys/fs/fuse/fuse_device.c stable/12/sys/fs/fuse/fuse_file.c stable/12/sys/fs/fuse/fuse_file.h stable/12/sys/fs/fuse/fuse_internal.c stable/12/sys/fs/fuse/fuse_internal.h stable/12/sys/fs/fuse/fuse_io.c stable/12/sys/fs/fuse/fuse_io.h stable/12/sys/fs/fuse/fuse_ipc.c stable/12/sys/fs/fuse/fuse_ipc.h stable/12/sys/fs/fuse/fuse_kernel.h stable/12/sys/fs/fuse/fuse_main.c stable/12/sys/fs/fuse/fuse_node.c stable/12/sys/fs/fuse/fuse_node.h stable/12/sys/fs/fuse/fuse_param.h stable/12/sys/fs/fuse/fuse_vfsops.c stable/12/sys/fs/fuse/fuse_vnops.c stable/12/sys/sys/param.h stable/12/tests/sys/fs/Makefile stable/12/tests/sys/fs/fusefs/ stable/12/tests/sys/fs/fusefs/access.cc stable/12/tests/sys/fs/fusefs/allow_other.cc stable/12/tests/sys/fs/fusefs/bmap.cc stable/12/tests/sys/fs/fusefs/create.cc stable/12/tests/sys/fs/fusefs/default_permissions.cc stable/12/tests/sys/fs/fusefs/default_permissions_privileged.cc stable/12/tests/sys/fs/fusefs/destroy.cc stable/12/tests/sys/fs/fusefs/dev_fuse_poll.cc stable/12/tests/sys/fs/fusefs/fifo.cc stable/12/tests/sys/fs/fusefs/flush.cc stable/12/tests/sys/fs/fusefs/forget.cc stable/12/tests/sys/fs/fusefs/fsync.cc stable/12/tests/sys/fs/fusefs/fsyncdir.cc stable/12/tests/sys/fs/fusefs/getattr.cc stable/12/tests/sys/fs/fusefs/interrupt.cc stable/12/tests/sys/fs/fusefs/io.cc stable/12/tests/sys/fs/fusefs/link.cc stable/12/tests/sys/fs/fusefs/locks.cc stable/12/tests/sys/fs/fusefs/lookup.cc stable/12/tests/sys/fs/fusefs/mkdir.cc stable/12/tests/sys/fs/fusefs/mknod.cc stable/12/tests/sys/fs/fusefs/mockfs.cc stable/12/tests/sys/fs/fusefs/mockfs.hh stable/12/tests/sys/fs/fusefs/mount.cc stable/12/tests/sys/fs/fusefs/nfs.cc stable/12/tests/sys/fs/fusefs/notify.cc stable/12/tests/sys/fs/fusefs/open.cc stable/12/tests/sys/fs/fusefs/opendir.cc stable/12/tests/sys/fs/fusefs/read.cc stable/12/tests/sys/fs/fusefs/readdir.cc stable/12/tests/sys/fs/fusefs/readlink.cc stable/12/tests/sys/fs/fusefs/release.cc stable/12/tests/sys/fs/fusefs/releasedir.cc stable/12/tests/sys/fs/fusefs/rename.cc stable/12/tests/sys/fs/fusefs/rmdir.cc stable/12/tests/sys/fs/fusefs/setattr.cc stable/12/tests/sys/fs/fusefs/statfs.cc stable/12/tests/sys/fs/fusefs/symlink.cc stable/12/tests/sys/fs/fusefs/unlink.cc stable/12/tests/sys/fs/fusefs/utils.cc stable/12/tests/sys/fs/fusefs/utils.hh stable/12/tests/sys/fs/fusefs/write.cc stable/12/tests/sys/fs/fusefs/xattr.cc