diff options
| author | anton <anton@cvs.openbsd.org> | 2019-07-10 16:43:21 +0000 |
|---|---|---|
| committer | anton <anton@cvs.openbsd.org> | 2019-07-10 16:43:21 +0000 |
| commit | d8bf193ec09f26b570daa057ab9961744de1794d (patch) | |
| tree | fb42455d3d5d0bb3236d5a9551cade60758d5ad7 /sys/msdosfs | |
| parent | cfb2b7e76d2d97505ffb3e2ac6a43561e980f07a (diff) | |
Make read/write of the f_offset field belonging to struct file MP-safe;
as part of the effort to unlock the kernel. Instead of relying on the
vnode lock, introduce a dedicated lock per file. Exclusive write access
is granted using the new foffset_enter and foffset_leave API. A
convenience function foffset_get is also available for threads that only
need to read the current offset.
The lock acquisition order in vn_write has been changed to match the one
in vn_read in order to avoid a potential deadlock. This change also gets
rid of a documented race in vn_read().
Inspired by the FreeBSD implementation.
With help and ok mpi@ visa@
Diffstat (limited to 'sys/msdosfs')
| -rw-r--r-- | sys/msdosfs/msdosfs_vnops.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sys/msdosfs/msdosfs_vnops.c b/sys/msdosfs/msdosfs_vnops.c index a2e465cbb3a..d39361ce732 100644 --- a/sys/msdosfs/msdosfs_vnops.c +++ b/sys/msdosfs/msdosfs_vnops.c @@ -1,4 +1,4 @@ -/* $OpenBSD: msdosfs_vnops.c,v 1.122 2018/06/21 14:17:23 visa Exp $ */ +/* $OpenBSD: msdosfs_vnops.c,v 1.123 2019/07/10 16:43:19 anton Exp $ */ /* $NetBSD: msdosfs_vnops.c,v 1.63 1997/10/17 11:24:19 ws Exp $ */ /*- @@ -2017,7 +2017,7 @@ filt_msdosfsread(struct knote *kn, long hint) return (1); } - kn->kn_data = dep->de_FileSize - kn->kn_fp->f_offset; + kn->kn_data = dep->de_FileSize - foffset_get(kn->kn_fp); if (kn->kn_data == 0 && kn->kn_sfflags & NOTE_EOF) { kn->kn_fflags |= NOTE_EOF; return (1); |