Bug 266886
| Summary: | [FUSEFS] Handling of l_whence with fcntl(F_GETLK) | ||
|---|---|---|---|
| Product: | Base System | Reporter: | John Millikin <jmillikin> |
| Component: | kern | Assignee: | Alan Somers <asomers> |
| Status: | Closed FIXED | ||
| Severity: | Affects Some People | CC: | asomers, emaste, grahamperrin |
| Priority: | --- | Flags: | asomers:
mfc-stable13+
asomers: mfc-stable12+ |
| Version: | CURRENT | ||
| Hardware: | Any | ||
| OS: | Any | ||
| URL: | https://reviews.freebsd.org/D37014 | ||
|
Description
John Millikin
2022-10-07 10:49:07 UTC
I can't reproduce this problem. If I do the following: ASSERT_NE(-1, lseek(fd, 500, SEEK_SET)); fl.l_start = 0; fl.l_len = 10; fl.l_pid = 42; fl.l_type = F_RDLCK; fl.l_whence = SEEK_CUR; fl.l_sysid = 42; ASSERT_NE(-1, fcntl(fd, F_GETLK, &fl)) << strerror(errno); Then the server gets a FUSE_GETLK operation with start set to 500 and end set to 509, as it ought to. I can't reproduce it with FUSE_SETLK either. Could you help provide some more complete reproduction steps? I think my initial message was partially incorrect -- the offsets are being calculated correctly, it's just that `l_whence` doesn't get set to `SEEK_SET` when the call is complete.
/* &fl populated per your example */
fcntl(fd, F_GETLK, &fl));
/* fuse server request and response
RECV fuse_lk_in { lk: fuse_file_lock { start: 500, end: 509, .. }, .. }
SEND fuse_lk_out { lk: fuse_file_lock { start: 500, end: 509, .. } }
*/
ASSERT_EQ(fl.l_start, 500);
ASSERT_EQ(fl.l_len, 10);
ASSERT_EQ(fl.l_whence, SEEK_SET); /* fails */
In other words, I would expect one of the following to be true after fcntl returns:
1. l_start is an absolute location within the file, and l_whence is SEEK_SET.
2. l_start is relative to the file position, and l_whence is SEEK_CUR.
(In reply to John Millikin from comment #2) Ok, I agree. As the man page says, l_whence should be set to SEEK_SET on return from a successful F_GETLK operation. After all, it's describing some other lock, not the one you queried about. However, I don't see any reason why l_whence should be set to SEEK_SET on return from F_SETLK or F_SETLKW. (There's a separate problem with SEEK_END and F_SETLK, which I'll fix. fusefs doesn't correct the offset passed to the daemon.) A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=3c3b906b54236841d813fd9a01b1e090f39558ea commit 3c3b906b54236841d813fd9a01b1e090f39558ea Author: Alan Somers <asomers@FreeBSD.org> AuthorDate: 2022-10-11 23:00:07 +0000 Commit: Alan Somers <asomers@FreeBSD.org> CommitDate: 2022-10-17 13:09:50 +0000 fusefs: After successful F_GETLK, l_whence should be SEEK_SET PR: 266886 Reported by: John Millikin <jmillikin@gmail.com> MFC after: 2 weeks Reviewed by: emaste Differential Revision: https://reviews.freebsd.org/D37014 sys/fs/fuse/fuse_vnops.c | 1 + tests/sys/fs/fusefs/locks.cc | 69 ++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 68 insertions(+), 2 deletions(-) A commit in branch stable/12 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=311f68079ff29aabd594c6fbdc97c2bff5d91ba5 commit 311f68079ff29aabd594c6fbdc97c2bff5d91ba5 Author: Alan Somers <asomers@FreeBSD.org> AuthorDate: 2022-10-11 23:00:07 +0000 Commit: Alan Somers <asomers@FreeBSD.org> CommitDate: 2022-10-20 16:24:19 +0000 fusefs: After successful F_GETLK, l_whence should be SEEK_SET PR: 266886 Reported by: John Millikin <jmillikin@gmail.com> Reviewed by: emaste Differential Revision: https://reviews.freebsd.org/D37014 (cherry picked from commit 3c3b906b54236841d813fd9a01b1e090f39558ea) fusefs: fix VOP_ADVLOCK with SEEK_END When the user specifies SEEK_END, unlike SEEK_CUR, VOP_ADVLOCK must adjust lock offsets itself. Sort-of related to bug 266886. Reviewed by: emaste Differential Revision: https://reviews.freebsd.org/D37040 (cherry picked from commit f6e5319550f60170840f1a07a9cbdd45b5014a21) Approved by: kib (re) sys/fs/fuse/fuse_vnops.c | 34 +++++++- tests/sys/fs/fusefs/locks.cc | 191 +++++++++++++++++++++++++++++++++++++++++- tests/sys/fs/fusefs/mockfs.cc | 14 +++- 3 files changed, 234 insertions(+), 5 deletions(-) Triage: * assign to committer resolving * asomers@, attention to flags? A commit in branch stable/13 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=faea785d30533566fa03807cdbd8a49d5fd16254 commit faea785d30533566fa03807cdbd8a49d5fd16254 Author: Alan Somers <asomers@FreeBSD.org> AuthorDate: 2022-10-11 23:00:07 +0000 Commit: Alan Somers <asomers@FreeBSD.org> CommitDate: 2022-10-31 00:51:33 +0000 fusefs: After successful F_GETLK, l_whence should be SEEK_SET PR: 266886 Reported by: John Millikin <jmillikin@gmail.com> Reviewed by: emaste Differential Revision: https://reviews.freebsd.org/D37014 (cherry picked from commit 3c3b906b54236841d813fd9a01b1e090f39558ea) sys/fs/fuse/fuse_vnops.c | 1 + tests/sys/fs/fusefs/locks.cc | 69 ++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 68 insertions(+), 2 deletions(-) |
