Author: mjg
Date: Fri Sep 26 20:05:28 2014
New Revision: 272187
URL: http://svnweb.freebsd.org/changeset/base/272187
Log:
MFC r270993:
Fix up proc_realparent to always return correct process.
Prior to the change it would always return initproc for non-traced processes.
This fixes a regression in inferior().
Approved by: re (marius)
Modified:
stable/10/sys/kern/kern_descrip.c
stable/10/sys/kern/vfs_vnops.c
stable/10/sys/sys/file.h
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/kern/kern_descrip.c
==============================================================================
--- stable/10/sys/kern/kern_descrip.c Fri Sep 26 19:56:52 2014
(r272186)
+++ stable/10/sys/kern/kern_descrip.c Fri Sep 26 20:05:28 2014
(r272187)
@@ -477,7 +477,6 @@ kern_fcntl(struct thread *td, int fd, in
struct vnode *vp;
cap_rights_t rights;
int error, flg, tmp;
- u_int old, new;
uint64_t bsize;
off_t foffset;
@@ -761,26 +760,24 @@ kern_fcntl(struct thread *td, int fd, in
error = EBADF;
break;
}
+ vp = fp->f_vnode;
+ /*
+ * Exclusive lock synchronizes against f_seqcount reads and
+ * writes in sequential_heuristic().
+ */
+ error = vn_lock(vp, LK_EXCLUSIVE);
+ if (error != 0) {
+ fdrop(fp, td);
+ break;
+ }
if (arg >= 0) {
- vp = fp->f_vnode;
- error = vn_lock(vp, LK_SHARED);
- if (error != 0) {
- fdrop(fp, td);
- break;
- }
bsize = fp->f_vnode->v_mount->mnt_stat.f_iosize;
- VOP_UNLOCK(vp, 0);
fp->f_seqcount = (arg + bsize - 1) / bsize;
- do {
- new = old = fp->f_flag;
- new |= FRDAHEAD;
- } while (!atomic_cmpset_rel_int(&fp->f_flag, old, new));
+ atomic_set_int(&fp->f_flag, FRDAHEAD);
} else {
- do {
- new = old = fp->f_flag;
- new &= ~FRDAHEAD;
- } while (!atomic_cmpset_rel_int(&fp->f_flag, old, new));
+ atomic_clear_int(&fp->f_flag, FRDAHEAD);
}
+ VOP_UNLOCK(vp, 0);
fdrop(fp, td);
break;
Modified: stable/10/sys/kern/vfs_vnops.c
==============================================================================
--- stable/10/sys/kern/vfs_vnops.c Fri Sep 26 19:56:52 2014
(r272186)
+++ stable/10/sys/kern/vfs_vnops.c Fri Sep 26 20:05:28 2014
(r272187)
@@ -438,7 +438,8 @@ static int
sequential_heuristic(struct uio *uio, struct file *fp)
{
- if (atomic_load_acq_int(&(fp->f_flag)) & FRDAHEAD)
+ ASSERT_VOP_LOCKED(fp->f_vnode, __func__);
+ if (fp->f_flag & FRDAHEAD)
return (fp->f_seqcount << IO_SEQSHIFT);
/*
Modified: stable/10/sys/sys/file.h
==============================================================================
--- stable/10/sys/sys/file.h Fri Sep 26 19:56:52 2014 (r272186)
+++ stable/10/sys/sys/file.h Fri Sep 26 20:05:28 2014 (r272187)
@@ -139,6 +139,7 @@ struct fileops {
*
* Below is the list of locks that protects members in struct file.
*
+ * (a) f_vnode lock required (shared allows both reads and writes)
* (f) protected with mtx_lock(mtx_pool_find(fp))
* (d) cdevpriv_mtx
* none not locked
@@ -164,7 +165,7 @@ struct file {
/*
* DTYPE_VNODE specific fields.
*/
- int f_seqcount; /* Count of sequential accesses. */
+ int f_seqcount; /* (a) Count of sequential accesses. */
off_t f_nextoff; /* next expected read/write offset. */
union {
struct cdev_privdata *fvn_cdevpriv;
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